Appendix K. Preliminary Engineering Report Critical design and implementation issues need to be resolved early in the planning phase of a UV disinfection facility. The purpose of a preliminary engineering report is 1) to provide conceptual level layouts and preliminary cost estimates for implementation of UV disinfection at the water treatment plant ( WTP), and 2) to recommend an implementation plan for UV installation design and construction. Specific components of the preliminary engineering analysis are listed below:

  Identification of UV reactor design criteria and implementation issues   Evaluation of UV reactor alternatives and potential locations for the proposed installations in the plant treatment train   Determination of the hydraulic characteristics of the UV reactor and incorporate it into the hydraulic model of the plant   Development of estimates for capital, operational, and life cycle costs for each alternative   Comparison of feasible alternatives and development of implementation recommendations This appendix presents an example of a preliminary engineering report ( PER) for retrofitting a UV disinfection facility into an existing WTP. The basic elements involved in the planning phase of the UV installation are discussed in this report. The format and content of a site specific PER should be coordinated with the State. This example report is based largely on a predesign report prepared for North Shore Water Commission, Wisconsin ( Carollo Engineers 2001).

Chapter 3 of the Guidance Manual presents a detailed discussion of UV installation planning and design principles. A flowchart depicting the planning and design process is included in Figure 3.1. Table K. 1 presents a correlation between the flowchart elements discussed in Chapter 3 and respective sections in this appendix.

Table K. 1 Elements of the Planning and Design Process ( Ref. Figure 3.1)

Element Chapter 3 Section Appendix K Section( s) Define UV disinfection goals 3.1.1 K. 1, K. 2 Identify potential retrofit locations 3.1.2 K. 5 Determine design parameters 3.1.3 K. 2.2 Evaluate potential UV reactors 3.1.4 K. 3 Evaluate operational and control strategies 3.1.5 K. 4 Evaluate hydraulic profile and site layouts 3.1.6 K. 5 Compare retrofit options and costs; select retrofit locations 3.1.7 K. 6, K. 7, K. 8 UV Disinfection Guidance Manual K 1 June 2003 Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 2 June 2003 K. 1 Background of Example WTP A 20 million gallon per day ( mgd) surface WTP is used as an example in this appendix. The water treatment processes employed are coagulation and sedimentation pretreatment, granular media ( anthracite and sand) filtration followed by chlorine disinfection. Since the plant was put into service in the 1960s, water quality regulations have become more stringent. In addition, there are growing concerns over chlorine resistant pathogens ( e. g., Cryptosporidium) and production of chlorinated disinfection byproducts ( e. g., trihalomethanes, haloacetic acids). In order to upgrade the facility to meet current and future regulations and health concerns, several research studies have been performed involving the use of ozone, membranes, and UV disinfection. From the results of those studies, it was concluded that the most feasible and cost effective solution to achieve disinfection of chlorine resistant pathogens was to add UV disinfection to the current treatment train.

The following are the general performance goals of the UV installation for the example WTP:

  Provide 2 log Cryptosporidium inactivation.

  Provide an additional disinfection barrier for other chlorine resistant pathogens.

K. 2 UV Disinfection Criteria This section includes general information regarding the optimal application point for UV disinfection at the WTP and design considerations for implementation.

K. 2.1 Application Point and UV Transmittance One of the important parameters controlling UV installation design is the UV transmittance ( UVT) of the water to be treated ( section <IP_ADDRESS>). The lower the UVT, the greater the UV intensity is needed to provide a given UV dose at a given flowrate. UVT typically varies with source water, seasonally, and through the treatment processes. Consequently, a thorough UVT analysis was completed during development of design criteria.

K. 2.1.1 Point of Application for UV Disinfection In keeping with the content of this guidance manual, the UV disinfection alternatives assessed for the WTP were limited to applications after filtration. Based on statistical results of the filtered water ultraviolet absorbance at 254 nanometers ( A254) data, the UV reactors are sized based on a 0.032/ cm A254 ( 93 percent UVT; 10 mm path length; light at 254 nm), which is the 99th percentile minimum of the available A254 data.

Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 3 June 2003 K. 2.1.2 Treatment Chemical Impact on Absorbance Some chemicals used in water treatment absorb UV light and hence, can influence the design absorbance value, as discussed in Chapter 3.1.2 of the manual. Ferric iron and permanganate are two of these, and are used at the example WTP. Ferric iron strongly absorbs UV light; however, post filtration iron levels are generally low. Permanganate absorbs UV light, but at permanganate levels of less than 1 mg/ L, which is typically the case post filtration, the impact is not significant. Therefore, for the PER, chemical A254 is not considered to influence the UV design criteria.

K. 2.1.3 Power Quality Impact on Absorbance As stated in section <IP_ADDRESS>, the sensitivity of UV reactors to power fluctuations make electrical power supply a critical component of the UV installation planning and design. Preliminary pilot testing of UV reactors over the course of a year at this site did not indicate any problems with existing water utility power quality for the UV reactor's operational continuity. Therefore, for this PER, power quality is not considered to negatively impact the UV installation design.

K. 2.2 Inactivation Goals and UV Dose The goal of UV disinfection at the example WTP is to provide inactivation of chlorineresistant pathogens. By using UV disinfection, the general goal of improving public health protection will be met and compliance with the Long Term 2 Enhanced Surface Water Treatment Rule ( LT2ESWTR) Cryptosporidium inactivation requirements may be achieved, if needed ( 40 CFR 141.702). ( Source water sampling for " Bin" determination has not yet been completed at this example WTP, so the level of additional credit needed in the future is unknown.) UV disinfection credit will also be available for Giardia and virus inactivation. This additional UV disinfection credit will most likely reduce chlorine disinfection requirements, and hence, reduce disinfection by product formation.

The desired UV dose ( or validated reduction equivalent dose [ RED]) depends on the disinfection strategy of the individual UV installation. The State, utility, and designer must decide the log inactivation requirements for a target pathogen. Once this information is known, the UV dose can be established ( section 3.1.1). For this PER example, a UV dose of 40 mJ/ cm2 is recommended to achieve 2 log Cryptosporidium inactivation and is used for UV disinfection pre design purposes.

A 12 month pilot study was conducted to assess the long term disinfection efficiency and operation and maintenance ( O& M) issues. The study results indicated that lamp fouling and power quality issues should not be a concern for the facility ( Mackey et al. 2001).

Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 4 June 2003 K. 3 UV Installation Equipment General information on UV reactors and the types of reactor configurations used for water treatment is provided in this section.

K. 3.1 UV Lamp Types For the flowrates associated with the WTP applications in this example, the number of lamps needed for a low pressure ( LP) reactor would be excessive, so consideration is limited to low pressure high output ( LPHO) and medium pressure ( MP) lamps. The general relative characteristics of each of these lamp types are listed in Table K. 2. The ratio of number of lamps needed to achieve equivalent RED for LPHO lamps as compared to MP lamps is on the order of 6: 1.

Table K. 2 Relative Characteristics of LPHO and MP Lamps LPHO MP Lamp Power Output Low High Power Efficiency High Low Number of Lamps Needed High Low Operating Temperature ( ° C) 130   200 600  900 Typical Lamp Life ( hours) 8,000  12,000 3,000  8,000 K. 3.2 UV Reactor Configuration UV installations can be designed around open channel or closed vessel configurations. In keeping with the content of this guidance manual and the general trend of the drinking water industry, the conceptual designs developed herein are limited to MP and LPHO closed vessel reactors.

K. 4 UV Reactor Description This section contains information on the UV reactor design criteria for disinfection at the WTP.

K. 4.1 General UV Reactor Description Each UV reactor for the WTP should include appropriate control and electrical cabinets and an off line chemical cleaning ( OCC) system or an on line mechanical cleaning ( OMC) system for the lamps. The cleaning systems should allow for the removal of organic and inorganic foulants that have accumulated on the surfaces of the lamp sleeves.

Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 5 June 2003 K. 4.2 Process Control For disinfection of drinking water, the ability of the UV reactor to deliver the design RED of 40 mJ/ cm2 depends on the flowrate, feed water UVT, and UV intensity. UV intensity is subject to lamp aging, lamp sleeve cleanliness, and water quality ( mainly water UVT). The UV reactor should be designed to deliver the appropriate dose of UV light to the process flow based on predetermined maximum flowrate and minimum water quality parameter setpoints with an appropriate factor of safety ( see Chapter 3).

UV intensity sensors in each UV reactor should provide continuous performance verification of the reactor during operation. In case of lamp failure, the UV reactor programmable logic controller ( PLC) should be programmed to either replace one row of lamps with another row that was off, or turn the reactor off after replacing it with a stand by reactor. ( Note that Alternative 1, described in section K. 5.1, involves placing a UV reactor on each filter effluent pipe, therefore stand by reactors for individual filter installations are not provided). The failed lamp can then be replaced with minimal interruption of UV reactor operation.

In case of incorrect operation of lamps or low level of UV intensity, the PLC should display a warning to indicate to the operator that cleaning of the reactor should be performed. The operator initiates the cleaning of any reactor through the local human machine interface ( HMI). After selection, the UV reactor PLC turns on the stand by reactor. Then, the PLC closes the inlet and outlet valves and isolates the reactor to be cleaned.

K. 4.3 Expected UV Reactor Maintenance Although maintenance methods are installation and site specific, some general maintenance tasks have been developed and are briefly described in this section. As the UV reactor represents a critical disinfection process, preventative maintenance should be carried out on a routine basis to ensure that UV reactors reliably provide the specified dose ( 40 mJ/ cm2). Inadequate cleaning is a common cause of underdosing in UV reactors. The lamp sleeves should be cleaned regularly by OMC or periodic OCC, and manually cleaned periodically to supplement automatic cleaning. The cleaning frequency is dependent on the water quality. Chemical cleaning is most commonly done with dilute citric or phosphoric acid.

The effective life of the UV lamps depends on the minimum UV dose. The UV lamps should be replaced either at the end of their expected lifetime or following failure. Generally, UV lamps are replaced when the intensity has dropped to 70 percent of the original new lamp intensity ( following cleaning of the chamber). This typically occurs after about 8,000 to 12,000 hours ( approximately 300 to 500 days) of operation for LPHO lamps and about 3,000 to 8,000 hours ( approximately 100 to 300 days) for MP lamps. The front panel of the enclosures indicates the cumulative hours each lamp has operated. The lamp run time display will facilitate monitoring of lamp replacement needs.

Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 6 June 2003 K. 4.4 Power Needs UV reactor power needs to vary depending on the type of equipment that is installed and UVT of the water being disinfected. The LPHO reactors used for this pre design have power requirements of approximately 20 kW for treating 20 mgd. The MP UV reactors require about 130 kW for treating 20 mgd. As indicated in Table K. 3 through K. 5, additional power would be necessary to allow for future expansion of the UV facilities.

K. 5 Site Plans and Facility Layouts The preferred process location for a UV installation at a WTP is downstream of the filters and upstream of the high service pumps ( section 3.1.2). At the example WTP, there are three viable alternatives for the UV installation downstream of the filters:

  Alternative 1   Filter Gallery   Alternative 2   Existing Chemical Room   Alternative 3   New Building There are eight granular media filters at the WTP. Alternative 1 involves placing one UV reactor on the effluent pipe of each filter in the filter gallery between the filters and clearwell. Alternative 2 is to construct the UV installation in a chemical room in the WTP between the low service pumps and the reservoir. Alternative 3 involves constructing a new building between the low service pumps and the reservoir to house the UV reactors. Figure K. 1 presents a portion of the plants hydraulic profile and indicates the vertical locations of the three viable alternatives.

The construction requirements and preliminary drawings for each alternative are illustrated and described in the following section, along with preliminary design criteria. Costs for the three alternatives are also compared. The preliminary site specific design criteria are provided for example purposes only. Application specific design criteria should be provided by the UV manufacturer for each individual UV disinfection implementation project on a case bycase basis.

K. 5.1 Alternative 1  Filter Gallery In Alternative 1, one 3 mgd UV reactor is installed on the discharge pipe of each of the eight filters, as shown in Figure K. 2. The UV reactors would be installed below the hydraulic grade line ( HGL) of the existing clearwell to ensure constant submergence ( section <IP_ADDRESS>). Flow through the UV reactors is by gravity from the filters into the clearwell. During filter backwashing and filter to waste cycles, valves located at the influent of each UV reactor can be closed to keep the reactor flooded while it is taken off line.

Compared to the other alternatives, construction of Alternative 1 is the simplest. Construction would include lowering the level in the clearwell to below the filter discharge Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 7 June 2003 pipes, then taking each filter off line individually to install the new piping, valves, and UV reactor. This would preclude significant disruption of plant operation during construction.

Figure K. 1 Portion of the WTP Hydraulic Profile and Alternative Locations for UV Implementation ( Carollo Engineers 2001)

Low Service Pump Filters Reservoir Clearwell Elev. 72.0'

Elev. 56.5'

Elev. 69.0' Alternative 2 Alternative 3 Alternative 1 Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 8 June 2003 Figure K. 2 Alternative 1  Filter Gallery ( Carollo Engineers 2001)

Note: UV reactor is installed on discharge pipe of each filter. Valve on UV reactor influent is closed to maintain water in the UV reactor during filter backwashing.

Some concerns associated with installing UV reactors in the filter gallery are space constraints, climate control, and impact on filtration. In the design, care would need to be taken to allow enough space for maintenance and construction of the UV installation. Although the UV installation in this example will fit into the existing filter gallery of the WTP, generally there is little room to work in these locations. In addition, depending on the location of the WTP, humidity and pipe sweating in this space might be a concern. However, there are protective climate controlled enclosures available for these conditions, though they add to cost and maintenance needs. A detailed hydraulic analysis of the filters would need to be completed prior to designing a UV installation on the filter effluent piping. There must be adequate head available from the filters to the clearwell to allow for the addition of a UV reactor that will not Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 9 June 2003 adversely affect the filter performance. Furthermore, in the event of a UV reactor shutdown, the filter associated with that UV reactor shutdown would also need to be removed from service.

The preliminary design criteria for Alternative 1 are provided in Table K. 3. Due to the large size of the LPHO reactors, they will not fit into the filter gallery. Therefore, only the MP reactors are considered for Alternative 1.

Table K. 3 Preliminary Design Criteria   Alternative 1   MP UV Reactors Description Unit Criteria Current Future Treatment plant capacities Flowrate mgd 20 40 Water quality UVT In a 10mm quartz cell @ 254 nm % UVT 93 93 Ultraviolet reactors Type of reactors: medium pressure Number of reactors No 8 16 Number of banks per reactor No. 2 2 Number of lamps per bank No. 4 4 Total number of lamps per reactor No. 8 8 Input power per lamp W 2000 2000 Total operating electric load kW 128 256 Total installed electric load kW 128 256 Headloss through reactor ( at current and future flowrates) Inches 12 36 Approximate dimensions of each UV reactor Length Inches 22 50 Width Inches 36 36 Height Inches 26 26 Flanges diameter Inches 12 12 As stated previously, the eight UV reactors listed in Table K. 3 are designed for a maximum capacity of 3 mgd each. This design is based on the assumption that one UV reactor would be taken off line periodically during a filter backwash cycle. The WTP must be able to treat 20 mgd with one filter out of service, so the remaining seven UV reactors would need to be able to disinfect the maximum plant flow. This arrangement also provides reactor redundancy. If one UV reactor were taken out of service, the associated filter would also be taken out of service.

In this example, future plant expansions needed to be taken into account. For the present analysis, provisions are made so that future expansion of the UV installation to an ultimate flow of 40 mgd will be possible. If the filter capacities can be expanded to 40 mgd, the UV installation expansion will necessitate placing two UV reactors ( 16 total) in series along each filter effluent pipe. During the construction of the initial design for 20 mgd, adequate space and Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 10 June 2003 mechanical layouts would be provided for the addition of a second UV reactor. For example, a section of pipe located at the outlet of the UV reactor for the 20 mgd design could be designed for easy removal and installation of a second UV reactor.

K. 5.2 Alternative 2  Existing Chemical Room Alternative 2 consists of installing three 10 mgd reactors ( 2 operational + 1 stand by) in an existing chemical room in the WTP, as shown in Figure K. 3. This alternative necessitates placing the UV reactors above the existing HGL of the plant. The low lift clearwell pumps provide the head through the UV reactors. ( It is generally more advantageous to place the UV reactors below the HGL. However, due to the space constraints at the example WTP, and to provide an example of issues that may arise during design, this option is discussed.)

Figure K. 3 Alternative 2  Existing Chemical Room with UV Reactors ( Carollo Engineers 2001)

In theory, an outlet weir structure would be a viable option to raise the HGL of the plant to ensure constant submergence of the UV reactors ( section <IP_ADDRESS>). In this case, there is not enough space for such a structure. To ensure constant submergence of the UV reactors, a vertical pipe at the outlet header would maintain the water level at an elevation above the top of Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 11 June 2003 the UV reactors. Air vacuum valves would be installed on the inlet and the effluent vertical pipe to counteract siphon effects on the UV reactors. The discharge from the effluent header would then flow by gravity to the reservoirs. The hydraulic design of the inlet and outlet channels provides a continuous equal flow split between the reactors ( section <IP_ADDRESS>).

The construction needs of Alternative 2 are more difficult than Alternative 1. A 36 inch finished water pipe from the low head pumps would need to be taken out of service long enough to cut the pipe and tie in a new section with fittings and valves for connection of the new UV reactors. The existing equipment would need to be moved to alternate locations to accommodate the new large piping and UV reactors, and the floor would need to be cut to provide clearance for the piping to and from the lower floor.

Other issues with Alternative 2 are that space constraints in the chemical room, possible structural upgrades of the building, and raising the HGL of the plant. To allow for adequate space for maintenance, piping, and instrumentation, the existing chemical equipment in the room would need to be removed and reinstalled elsewhere in the plant. Since this is a second level room, a detailed structural analysis would need to be completed to ensure the floor is able to withstand the load of the UV installation. If structural upgrades are needed, they could prove to be expensive and difficult to design and construct. Installing the UV reactors in the second level room above the HGL would significantly increase the total dynamic head ( TDH) placed on the low lift clearwell pumps. Therefore, pump upgrades would be necessary to overcome the additional headloss of the UV installation.

K. 5.3 Alternative 3  New Building Alternative 3 includes constructing a new building to house three 10 mgd UV reactors ( 2 operational for 20 mgd + 1 standby) and related equipment. The building layout and UV design for Alternative 3 is presented in Figures K. 4 and K. 5. The 36 inch finished water line from the low service clearwell pumps would be modified to provide flow to the UV reactors in the new building. The new facility would include a two level structure to house mechanical and electrical equipment and large diameter piping to convey the filtered water through the UV reactors. The UV reactors would be installed in the basement of the new building below the HGL of the plant to ensure constant submergence. The hydraulic design of the inlet and outlet channels would provide an equal flow split between the reactors, and the discharge would flow under pressure to the reservoirs.

The UV building design and mechanical piping shown in Figures K. 4 and K. 5 are for preliminary design and cost estimates only. If this option were selected, the building size and configuration for this alternative would need to be evaluated in more detail during the design phase and adjusted as necessary, depending on the final UV reactors selected to be used.

Construction for Alternative 3 would be the most involved of the three options because it would include excavation and construction of a new building. Besides the building construction, the project would involve tying into the existing 36 inch finished water pipe in two locations below grade, and modifying site amenities such as pavement and landscaping. In addition, the new building would also need new power, control, and security systems as well as plumbing, HVAC, etc.

Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 12 June 2003 Figure K. 4 Alternative 3  New Building with UV Reactors   Plan View ( Carollo Engineers 2001)

Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 13 June 2003 Figure K. 5 Alternative 3  New Building with UV Reactors   Section View ( Carollo Engineers 2001)

The preliminary design criteria for Alternatives 2 and 3 using the MP UV reactors are presented in Table K. 4.

Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 14 June 2003 Table K. 4 Preliminary Design Criteria   Alternatives 2 and 3   MP UV Reactors Description Unit Criteria Current Future Treatment plant capacities Flowrate mgd 20 40 Water quality UVT in a 10mm quartz cell at 254 nm % UVT 93 93 Ultraviolet reactors Type of reactors: medium pressure Number of reactors No. ( Duty + Standby) 2+ 1 2 + 1 Number of banks per reactor No. 2 2 Number of lamps per bank No. 8 8 Total number of lamps per reactor No. 16 16 Input power per lamp W 4000 4500 Total operating electric load kW 128 144 Total installed electric load kW 192 216 Headloss through reactor ( at current & future flows) Inches 10 48 Approximate dimensions of each UV reactor Length Inches 48 48 Width Inches 49 49 Height Inches 41 41 Flanges diameter Inches 30 30 The three MP UV reactors selected have design capacities of 10 mgd each. Three 10 mgd UV reactors for the 20 mgd design provide one stand by reactor in the event of a malfunction, cleaning, or maintenance of one UV reactor.

Note that for expansion of the UV installation using the MP reactors given in Table K. 4, the size and number of UV reactors remains constant. In order to provide extra lamp intensity to meet dose requirements at the ultimate flow, 4000 W lamps would replaced with 4500 W lamps. ( Note that re validation of the reactors with the 4500 W lamps would be required ( 40 CFR141.729 ( d)).

The preliminary design criteria using the LPHO reactors for Alternatives 2 and 3 is provided in Table K. 5.

Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 15 June 2003 Table K. 5 Preliminary Design Criteria   Alternatives 2 and 3   LPHO UV Reactors Criteria Description Unit C urrent Future Treatment plant design capacities Plant flowrate mgd 20 40 Water quality UVT in a 10mm quartz cell at 254 nm % UVT 93 93 Ultraviolet reactors Type of reactors: Low Pressure High Output Number of reactors No ( Duty + Standby) 2+ 1 2+ 1 Number of rows per reactor( 1) No. 5 9 Number of rows with lamps installed No. 4 8 Number of lamps per row No. 12 12 Total number of lamps per reactor No. 48 96 Input power per lamp W 200 200 Total operating electric load kW 19.2 38.4 Total installed electric load kW 28.8 57.6 Headloss through reactor ( at current & future flows) Inches 24 35 Approximate dimensions of each UV reactor Length( 2) Inches 110 144 Width Inches 51 51 Height Inches 100 100 Flanges diameter Inches 32 32 1 Preliminary design assumes one spare row in addition to current flow demand requirements for installation of lamps in the future. 2 Length varies depending on the number of rows installed.

The expansion from 20 mgd to 40 mgd using the LPHO UV reactors would be accomplished by adding additional rows of lamps to the reactor. The UV manufacturers would oversize the reactor and additional rows of lamps could be inserted as needed for increasing flow capacities. However, UV reactor validation would need to be done both with and without the additional rows for the maximum and ultimate flow conditions.

Alternatively, the UV installation could be sized to allow additional UV reactors to be installed for expansion. Initially, three 10 mgd reactors would be installed for a capacity of 20 mgd ( 2 operational and 1 standby). Space would be provided to install two additional reactors in the future for a capacity of 40 mgd ( 4 operational and 1 standby).

These examples of UV installation expansion alternatives provide various options to the designer. To confidently design for future UV installation expansions, it will be critical to have an accurate flow projection and adequate space for the UV installation expansion. In addition to the UV reactors needed for an expansion, mechanical piping, controls, instrumentation, and wiring would need to be considered during the preliminary engineering phase. Furthermore, the designer should work closely with the UV manufacturer to decide on an expansion plan that has been proven to work effectively and efficiently for the specific UV installation design.

Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 16 June 2003 K. 6 Preliminary Capital and O& M Cost Estimates The preliminary capital, operational, and maintenance costs for each alternative are summarized in this section. Estimated costs presented for Alternative 1 are based solely on the MP design. The LPHO UV reactors used for comparison here would not fit into the filter gallery and so was not considered for that alternative.

K. 6.1 Capital Cost Estimate Summary The estimated capital improvement costs for each alternative are summarized in Table K. 6. Total project cost includes UV reactors, construction cost, engineering services, and a 20 percent estimating contingency.

The cost estimates presented for Alternative 1 in Table K. 6 are based on using eight MP UV reactors. The costs presented for Alternatives 2 and 3 were developed around using three MP and LPHO UV reactors. The equipment cost for installing the MP UV reactors for all three Alternatives is higher than installing LPHO UV reactors for Alternatives 2 and 3. However, due to the relatively simple construction details associated with Alternative 1, the total project cost is considerably lower than Alternatives 2 and 3, which require significant construction provisions. A comparison of these alternatives is provided in section K. 7.

Table K. 6 Preliminary Capital Cost Estimates UV Reactor Cost Total Project Cost Annualized Capital Cost1 Alternative 1 Filter Gallery ( MP) $ 531,000 $ 1,900,000 $ 166,000 Alternative 2 Chemical Room ( MP) $ 556,000 $ 2,400,000 $ 209,000 Alternative 2 Chemical Room ( LPHO) $ 450,000 $ 2,300,000 $ 201,000 Alternative 3 New Building ( MP) $ 556,000 $ 2,800,000 $ 244,000 Alternative 3 New Building ( LPHO) $ 450,000 $ 2,700,000 $ 235,000 1 Annualized costs calculated at 6 percent interest for 20 years.

K. 6.2 Preliminary Operating and Maintenance Costs Table K. 7 presents a summary of the estimated O& M costs and total annualized costs for each alternative ( four MP reactors in service for Alternative 1, two MP and LPHO UV reactors are in service for Alternatives 2 and 3). Detailed O& M costs for an average flow of 10 mgd are provided for each alternative and UV reactors in Tables K. 8 and K. 9.

Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 17 June 2003 Table K. 7 Estimated UV Disinfection Costs Annul O& M Cost1 Annualized Capital Cost2 Total Annual Cost Annual Difference3 Alternative 1 $ 72,000 $ 166,000 $ 238,000 $ 1,000 Alternative 2 ( MP) $ 111,000 $ 209,000 $ 320,000 $ 83,000 Alternative 2 ( LPHO) $ 36,000 $ 201,000 $ 237,000  0 Alternative 3 ( MP) 111,000 $ 244,000 $ 355,000 $ 118,000 Alternative 3 ( LPHO) $ 36,000 $ 235,000 $ 271,000 $ 34,000 1. Costs for UV intensity sensor calibrations, lamp sleeve, ballast and sensor replacement are not included. 2. Annualized costs calculated at 6 percent interest for 20 years. 3. Relative to the least expensive alternative ( Alternative 2 LPHO).

Table K. 8 MP UV Installation O& M Cost Estimates for Alternatives 1, 2 and 3 O& M Costs Alt. 1 Alts. 2 & 3 Average Plant Flow 10 mgd 1  Power Consumption Annual power consumption of lamps in kWh 530,155 883,5921 Price of electricity ($/ kWh) 0.10 0.10 Annual Expenses ($) 53,015 88,359 2  Consumables Lamp replacement # operating 32 $/ Lamp 500 (# 1) 600(# 2& 3) 17,500 21,000 # replaced / yr 35 Annual Expenses ($) 17,500 21,000 3  Labor Lamps # replaced / yr 35 Time ( hr) 8.8 15 min / lamp Cleaning 1 clngs / yr / reactor 3 Time ( hr) 9.0 3 hrs / cleaning Total Time ( hr) 17.8 $/ hr 65 65 Annual Expenses ($) 1,153 1,153 TOTAL COSTS 1  Power Consumption 53,015 88,359 2  Consumables 17,500 21,000 3  Labor 1,153 1,153 4  Chemicals 100 100 Total Annual Costs 71,770 110,610 COSTS PER MG TREATED Costs per MG Treated $/ MG 20.00 30.00 1 Alternative 1 utilizes eight smaller UV reactors while Alternatives 2 and 3 utilize 2 large reactors. At an average flow of 10 mgd, the large UV reactors operate at the lowest possible setting, which is higher than required at 10mgd.

Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 18 June 2003 Table K. 9 LPHO UV Installation O& M Cost Estimates for Alternatives 2 and 3 O& M Costs Average Plant Flow 10 mgd 1  Power Consumption Annual power consumption of lamps in kWh 168,303 Price of electricity ($/ kWh) 0.10 Annual Expenses ($) 16,830 2  Consumables Lamp replacement # operating 96 $/ Lamp 150 12,600 # replaced / yr 84 Annual Expenses ($) 12,600 3  Labor Lamps # replaced / yr 84 Time ( hr) 21.0 15 min / lamp Cleaning 1 clngs / yr / reactor 24 Time ( hr) 72.0 3 hrs / cleaning Total Time ( hr) 93.0 $/ hr 65 Annual Expenses ($) 6,045 TOTAL COSTS 1  Power Consumption 16,830 2  Consumables 12,600 3  Labor 6,045 4  Chemicals 600 Total Annual Costs 36,070 COSTS PER MG TREATED $/ MG 10.00 Power consumption represents the majority of the operational cost. The power cost used for calculation of the annual O& M costs was $ 0.10/ kWh. As expected, the MP reactors have considerably higher power costs associated with their operation than the LPHO reactors ( Tables K. 8 and K. 9).

Lamp replacement costs are also significant. Cost of lamp replacement is based on an estimated lamp life of 10,000 hours and $ 150/ lamp equipment cost for the LPHO reactors. The MP estimated lamp life is 8,000 hours with a lamp replacement cost of $ 500/ lamp for Alternative 1 and a lamp cost of $ 600/ lamp for Alternatives 2 and 3.

Estimated labor needs range from 18 hours for the MP UV installation to 93 hours per year for the LPHO UV installation. Labor estimates are based on lamp replacement at four lamps per hour and three hours per cleaning.

Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 19 June 2003 K. 7 Summary of Alternatives and their Advantages and Disadvantages A comparison of the three alternatives is presented in this section. The alternative comparisons are based on cost, feasibility of construction, and ease of maintenance. The advantages and disadvantages of each alternative are summarized in Table K. 10.

Table K. 10 Advantages and Disadvantages of Each Alternative Alternative 1   Filter Gallery   New building not necessary   Damp during periods of the year   Below existing hydraulic grade line ( HGL)   Needs protective cabinet for each UV reactor   Relatively simple construction   Tight quarters for construction and maintenance   Likely no plant down time for construction   Less manufacturer flexibility   Lowest capital cost   Must take a filter off line for UV reactor maintenance   Does not accommodate expansion easily   No redundancy at maximum flow Alternative 2   Chemical Building   New building not necessary   UV reactors above the plant HGL   Main floor access   Difficult construction constraints   Uncertainty associated with structural upgrades   Very limited space for relocation of existing   Chemical equipment to other parts of the plant   Low lift pump upgrades necessary Alternative 3   New Building   Ample space for UV reactors and controls   Highest capital and total project cost   UV reactors placed below the plant HGL   Necessitates a new building   Room for future expansion   Longer construction schedule   Flexibility in UV installation design options   Custom designed space for UV reactors K. 8 Conclusions and Recommendations Alternative 1, which involves the installation of the UV reactors in the filter gallery, is the least expensive option. However, there are concerns about the moisture associated with the location that may adversely affect the performance of the UV reactors and cause maintenance problems. Servicing and maintaining the UV reactors in the filter gallery and installing the necessary control panels might be problematic based on space constraints. In addition, to expand the capacity of the UV installation to accommodate the ultimate flow ( 40 mgd), the size of the pipes connecting the UV reactors to the filter effluent pipes would have to be increased and an additional UV reactor would have to be installed. Furthermore, Alternative 1 does not provide adequate redundancy at the ultimate flow.

Alternative 2, retrofitting the existing chemical feed room has the advantage of not requiring a new building. However the disadvantages of this option include the space limitations, associated pump upgrade needs and the need to find a new location for the chemical feed equipment currently housed in that room.

Proposal Draft Appendix K. Preliminary Engineering Report UV Disinfection Guidance Manual K 20 June 2003 Alternative 3, constructing a building addition to the WTP, is the most expensive alternative, but this option has some important advantages over Alternatives 1 and 2. The new building would offer flexibility in design options. The design would not be limited to using the MP or LPHO reactors; any UV reactors could be accommodated. There would be room for future expansion of the UV installation, if necessary, and ample space would be provided for mechanical and instrument layouts. The UV reactors would be installed below the existing hydraulic grade line of the plant to ensure submergence of the reactors.

Although Alternative 3 has some distinct advantages over Alternatives 1 and 2, the capital cost is significantly higher, due to the cost of the new building and appurtenances. Alternative 1 is the most economical alternative, but does not accommodate expansion easily and provides no redundancy at maximum flow. The disadvantages of Alternative 2, including lack of space for the existing chemical equipment, make this alternative the least desirable.

Given the above discussion, and based on both economical and non economical criteria for comparison in this example, including anticipated future expansion needs, the ranking of the alternatives from most desirable to least desirable is as follows:

  Most desirable   Alternative 3, New Building   Next best option   Alternative 1, Filter Gallery   Least desirable   Alternative 2, Existing Chemical Room K. 9 References Carollo Engineers. 2001. Weber basin water treatment plant No. 3 expansion. Layton, Utah.

Mackey, E. D., R. S. Cushing, and G. F. Crozes. 2001. Practical Aspects of UV Disinfection. Denver, Colo.: AWWA Research Foundation.

Proposal Draft Appendix L. Regulatory Timeline The purpose of this appendix is to provide utilities with a timeline ( Figure L. 1) to assist in planning and implementation of tasks to achieve compliance with the Long Term 2 Enhanced Surface Water Treatment Rule ( LT2ESWTR). The timelines present the important tasks that utilities are likely to complete; however, the tasks and their duration will change based on utilityspecific priorities and constraints.

Tasks have been divided into two general categories: regulatory and engineering. Compliance dates and resulting planning activities are based on utility size ( i. e., systems serving fewer than 10,000 persons or systems serving 10,000 or more persons).

L. 1 Regulatory Tasks Regulatory tasks and milestones include key dates in the regulatory schedule such as monitoring requirements and compliance dates.

L. 1.1 Cryptosporidium Monitoring One of the key provisions of the LT2ESWTR is the requirement to conduct monitoring to determine Cryptosporidium removal/ inactivation requirements ( 40 CFR 141.702). Monitoring results will be used to determine a " bin classification," which prescribes the Cryptosporidium inactivation/ removal required. More information regarding the monitoring requirements is available in the Source Water Monitoring Guidance Manual for Public Water Systems for the LT2ESWTR.

L. 1.2 Compliance Deadlines for Cryptosporidium Treatment For utilities required to provide additional treatment for Cryptosporidium, the compliance deadline is the date when a utility must have implemented the selected treatment techniques ( 40 CFR 141.701). Table L. 1 summarizes the Cryptosporidium treatment compliance deadlines for the LT2ESWTR.

Table L. 1 LT2ESWTR Compliance Schedule Summary1 System Size Compliance Deadline for Systems Making No Capital Improvements for Compliance2 Serving 10,000 or more people 6 years after LT2ESWTR promulgation Serving fewer than 10,000 people 8 ½ years after LT2ESWTR promulgation 1 ( 40 CFR 141.701) 2 State may grant an additional two years for systems making capital improvements.

UV Disinfection Guidance Manual L 1 June 2003 Proposal Draft Appendix L. Regulatory Timeline UV Disinfection Guidance Manual L 2 June 2003 L. 2 Engineering Tasks and Milestones Engineering tasks and milestones include tasks that should be completed by a utility to develop and implement an LT2ESWTR compliance strategy.

L. 2.1 Process Evaluation and Planning Compliance with the LT2ESWTR Cryptosporidium treatment requirements will necessitate varied levels of process evaluation and planning. After compliance strategy options have been reviewed ( see section 3.1.5) and a decision has been made to implement UV disinfection, planning may include one or more of the following activities:

  Engaging the State during planning to ensure the installation of UV disinfection is approved   Conducting disinfection benchmarking and profiling if distribution system total trihalomethane ( TTHM) and five haloacetic acids ( HAA5) concentrations are at least 80 percent of the Stage 1 DBPR maximum contaminant levels for TTHM and HAA5 ( 40 CFR 141.711 713)

  Developing a capital improvement program that includes the necessary modifications for LT2ESWTR compliance ( i. e., UV disinfection)

  Evaluating and implementing funding alternatives Utilities are encouraged to seek approval of their LT2ESWTR compliance plan from the State before implementation of a compliance strategy. This may take several months and can have a significant impact on the implementation schedule, particularly when the State requires modifications. Because UV disinfection is a relatively new technology, the State may take longer to approve UV disinfection or require more significant involvement in the compliance strategy development.

L. 2.2 UV Installation Design The duration of the facility design phase will be contingent on a number of utility specific factors, including scope of design ( i. e., new facility or retrofit), scale of design ( size of facility), available in house resources, procurement methods, and validation testing requirements ( discussed in detail in chapters 3 and 4). The design will likely include one or more of the following tasks:

  Evaluation of equipment and contractor procurement methods   UV reactor procurement   UV installation design Proposal Draft Appendix L. Regulatory Timeline UV Disinfection Guidance Manual L 3 June 2003   UV reactor validation strategy determination Many States require final approval of process improvements. As such, utilities should review the UV installation design and validation strategy with the State. If the State is not consulted during these phases, additional time may be necessary to receive final approval.

L. 2.3 Construction and Startup The timeline in Figure L. 1 reflects a construction period of two years for both large and small utilities. However, the actual duration of construction and startup can vary significantly, depending on the scope of the project, the significance of the changes to the existing treatment plant, and other utility specific factors. Utilities should consider these factors during planning phases and adjust accordingly to ensure regulatory milestones are achieved by the necessary dates.

L. 3 Example Timeline Figure L. 1 presents example timelines that encompass the regulatory and engineering tasks discussed in the previous sections. Utilities may have site specific constraints that may shorten or extend the duration of the engineering tasks listed; however, regulatory milestones are not flexible.

Proposal Draft Appendix L. Regulatory Timeline Figure L. 1 Example LT2ESWTR Compliance Timeline 2003 2004 2 005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Task Description LT2ESWTR Proposal LT2ESWTR Promulgation Systems serving 10,000 or more persons Cryptosporidium monitoring Initial Bin Classification Process Evaluation and Planning Facility Design Construction and Startup*

Compliance Deadline Systems serving less than 10,000 persons Cryptosporidium monitoring Initial bin classification Process Evaluation and Planning Facility Design Construction and Startup*

Compliance Deadline * State may grant an additional 2 years for system making capital improvements Regulatory Tasks/ Milestones Engineering Tasks/ Milestones UV Disinfection Guidance Manual L 4 June 2003 Proposal Draft Appendix M. Compliance Forms This appendix is intended to supplement the monitoring information provided in section 5.4 with examples of monthly compliance report and monitoring log forms that utilities might use for reporting to the State. ( Note, these are only examples; the States may develop their own compliance forms and require additional monitoring.) The specific monitoring and reporting requirements for each utility should be confirmed with the State, and the forms should be modified accordingly. For those utilities with advanced control systems ( e. g., Supervisory Control and Data Acquisition ( SCADA)), it may be possible to automatically generate these reports and compliance forms.

To receive disinfection credit, the Long Term 2 Enhanced Surface Water Treatment Rule ( LT2ESWTR) requires validation testing of UV reactors to demonstrate a set of operating conditions where the UV reactor will deliver the required dose ( 40 CFR 141.729 ( d)). These operating conditions must include flowrate, UV intensity, and UV lamp status, and the utility must monitor these parameters during routine operation to ensure dose delivery. ( 40 CFR 141.729 ( d)). States may specify additional monitoring or reporting requirements. The example forms presented in this appendix list both required and recommended monitoring parameters ( required parameters are identified with the applicable rule citation).

Table M. 1 summarizes the recommended minimum level of monitoring and record keeping for utilities utilizing UV disinfection. For many of the UV reactor components, the required or recommended performance level is based on the measurement uncertainty of the specific equipment that was used when the UV reactor was validated. This uncertainty is used to determine the validation safety factor and recommended reduction equivalent dose ( i. e., operational UV dose), as described in section 4.2.

UV Disinfection Guidance Manual M 1 June 2003 Proposal Draft Appendix M. Compliance Forms UV Disinfection Guidance Manual M 2 June 2003 Table M. 1. Summary of Compliance Monitoring and Reporting Activities1, 2 Item Description Measured Parameter Recommended Monitoring Frequency Reporting Frequency Offspecification Validated Parameters for UV Dose Monitor reactor to ensure operation within conditions validated for required UV dose ( 40 CFR 141, Subpart W, Appendix D). Flowrate, UV intensity, lamp status, and other parameters ( e. g., UVT) used to monitor dose. Continuously. Record at least once every four hours ( daily for very small systems). Required monthly report of offspecification operation as a percent of distributed flow or operating time ( 40 CFR 141.730). 3 Calibration of UV Intensity Sensors Calibration checks compare the duty sensor to the reference sensor and are recommended at the power setting utilized during normal operation. Percent difference between duty and reference sensors relative to the level of uncertainty used in determining the RED. ( see section C. 4.7) Monthly. If a sensor fails for three consecutive months, then the sensor should be checked weekly and the manufacturer contacted. Requirements in a State approved protocol.

Calibration of UV Transmittance ( UVT) Monitor It is recommended that grab samples be collected to confirm performance. Percent difference relative to the manufacturer's guaranteed uncertainty. Weekly initially. Reduced frequency following oneyear of supporting data. NR.

1 Section 5.4.2 presents all recommended monitoring activities, including the compliance monitoring shown in this table. 2 Unless noted in the table with an LT2ESWTR citation, the monitoring is recommended and not required. 3 The reported off specification value is the percentage of water entering the distribution that was not treated with UV reactors operating within validated conditions. This is required by the LT2ESWTR ( 40 CFR 141.730). NR   No requirement The LT2ESWTR requires utilities to submit monthly reports to the State ( 40 CFR 141.730). At a minimum, the reports must detail operating performance during the reporting period and, specifically, the percent of total distributed volume treated during periods when the UV reactor( s) was off specification. An example monthly monitoring form is shown in Table M. 2. Tables M. 3 through M. 6 present a format that the utility can use to log operating data for development of the monthly reports. With minor modification, the example forms are applicable for any of the three control strategies discussed in section <IP_ADDRESS>: UV intensity setpoint, UV intensity and UV transmittance ( UVT) setpoint, and calculated dose.

For those utilities utilizing multiple reactors, the operation of each reactor must be monitored, recorded, and reported. Requirements for compliance monitoring beyond those established by the LT2ESWTR and the specific content of the monthly report will be established by the State and coordinated with all other reporting requirements. Additional information on UV reactor monitoring and maintenance is provided in Chapter 5.

Proposal Draft Appendix M. Compliance Forms UV Disinfection Guidance Manual M 3 June 2003 Greater detail on each of the example forms is provided below:

  Form M. 2 is an example of a summary report that would be completed by the utility and submitted to the State on a monthly basis.

  Forms M. 3A, M. 3B, and M. 3C are example reference forms for each of the three control strategies discussed in section <IP_ADDRESS>. These forms would be completed by the utility based on validation results and then referenced throughout the operation of the UV installation to confirm compliance.

  Form M. 4 is an example operating log that would be completed on a daily basis. The form would be used to record the operating status of the UV installation and to estimate the volume of water that was discharged during off specification operation.

  Form M. 5 is an example sensor calibration log. This log would be completed whenever sensor calibration checks are performed. The log would be used to record the results of the calibration testing as well to track any sensor recalibration or repair work that was completed.

  Form M. 6 is an example on line UVT monitor calibration log. This log would only be completed by those utilities that have included on line UVT monitors as part of their design. The log would be completed whenever UVT monitor calibration checks are performed. The log would be used to record the results of the calibration testing as well to track any recalibration or repair work that was completed.

Proposal Draft Appendix M. Compliance Forms Table M. 2 Example Monthly Report to State Reporting Period:

System/ Treatment Plant:

PWSID:

Monthly Reactor Operating Report Operating Data Off Specification1 Unit No. Operating Time ( Hours) Volume Treated ( Gallons) No. of Events Volume ( Gallons) Time ( Hours) Percent of Volume Treated % % % % % % % % %

TOTALS:

Compliance Certification:

By volume the total percent of off specification operation during the reporting period = %

Of the _____ sensors within those reactors that operated during this reporting period, _____ have been checked for calibration and were within the acceptable range of tolerance.

Signature of Principal Executive Officer or Authorized Agent: Date:

1 From Table M. 4 UV Disinfection Guidance Manual M 4 June 2003 Proposal Draft Appendix M. Compliance Forms Table M. 3A UV Intensity Setpoint Control Strategy1 Validated Operating Requirements to Achieve Disinfection Credit for ( Target Pathogen)

( Reference Document  See Instructions Below)

Validated Operating Conditions Flow Rate UV Intensity Log Inactivation2 1 This form is for use with a UV Intensity setpoint operating strategy. If a different operating strategy is employed by the utility, then one of the other sample reference forms should be used or a form summarizing the specific validation criteria necessary to confirm compliance using the selected operating strategy should be developed.

2 For those utilities that do not employ variable power settings or that have a single target log inactivation, this column may not be necessary.

Instructions:

This form should be completed based on the validation testing results and used as a reference document.

This form should be referenced to determine if the UV system is operating within its validated conditions and meeting the performance requirements for inactivation credit for the target pathogen.

UV Disinfection Guidance Manual M 5 June 2003 Proposal Draft Appendix M. Compliance Forms Table M. 3B UV Intensity and UVT Setpoint Control Strategy1 Validated Operating Requirements to Achieve Disinfection Credit for ( Target Pathogen)

( Reference Document  See Instructions Below)

Validated Operating Conditions Flow Rate UV Intensity UVT Log Inactivation2 1 This form is for use with a UV Intensity/ UVT setpoint operating strategy. If a different operating strategy is employed by the utility, then one of the other sample reference forms should be used or a form summarizing the specific validation criteria necessary to confirm compliance using the selected operating strategy should be developed.

2 For those utilities that do not employ variable power settings or that have a single target log inactivation, this column may not be necessary.

Instructions:

This form should be completed based on the validation testing results and used as a reference document.

This form should be referenced to determine if the UV system is operating within its validated conditions and meeting the performance requirements for inactivation credit for the target pathogen.

UV Disinfection Guidance Manual M 6 June 2003 Proposal Draft Appendix M. Compliance Forms Table M. 3C Calculated Dose Control Strategy1 Validated Operating Requirements to Achieve Disinfection Credit for ( Target Pathogen)

( Reference Document  See Instructions Below)

Validated Operating Conditions Flow Rate UV Intensity UVT Calculated Dose Log Inactivation2 1 This form is for use with a calculated dose operating strategy. If a different operating strategy is employed by the utility, then one of the other sample reference forms should be used or a form summarizing the specific validation criteria necessary to confirm compliance using the selected operating strategy should be developed.

2 For those utilities that do not employ variable power settings or that have a single target log inactivation, this column may not be necessary.

Instructions:

This form should be completed based on the validation testing results and used as a reference document.

This form should be referenced to determine if the UV system is operating within its validated conditions and meeting the performance requirements for inactivation credit for the target pathogen.

UV Disinfection Guidance Manual M 7 June 2003 Proposal Draft Appendix M. Compliance Forms Table M. 4 Daily UV Intensity Sensor and UVT Monitoring and Compliance Log1 UVT Monitor b Reading Reading Date: _______________________________________________ Unit Did Not Operate During This Monitoring Interval:

System/ Treatment Plant: _______________________________

PWSID: _____________________________________________ Operator Signature:

Unit Number: _______________________________

UV Transmittance Monitor: Grab Sample Collected: Y/ N If yes, complete Calibration Log Sheet.

Calibration Check Performed: Y/ N UV Intensity Sensors: Calibration Check Performed: Y/ N If yes, complete Calibration Log Sheet.

Cumulative UV Intensity Sensors Flow Rate Volume No. Time ( gpd) ( gals) Reading Reading Reading Reading Reading Reading Reading Reading 123456 Time Flow Rate UVT Acceptable ( Y/ N) UV Intensity Acceptable ( Y/ N) 2 Calculated Dose 2 Volume 3 Operating Time Off Spec ( Y/ N) Volume Off

Spec 4 Reading No. 1 Reading No. 2 Reading No. 3 Reading No. 4 Reading No. 5 Reading No. 6 Daily Total: A B Percent Off Specification by Volume: % > 5% ( Y/ N) 5 ( B/ A x 100)

Notes:

1 As presented, this form is most applicable to a calculated dose control strategy, but can be modified to suit all control strategies.

2 Only if applicable to selected control strategy.

3 Volume treated since last reading.

4 For systems that rely solely on manual readings, the volume off specification shall be calculated as the total volume discharged since the last recording interval during which operation within validated conditions was observed. If continuous monitoring is provided, then the volume off specification shall be only that portion of the volume distributed during the recording interval that was outside of the validated conditions.

5 LT2ESWTR requires that off specification be less than 5 percent by volume on a monthly basis for unfiltered systems ( § 141.721). For filtered systems, it is that off specification operation be less than 5 percent by volume on a monthly basis. The specific requirements for allowable off specification for filtered systems will be established by the state.

Instructions:

This form should be completed daily for each operating unit. If a unit did not operate during the 24 hour monitoring interval, please note as such in the box at the top of the log.

This form is intended for periodic manual monitoring of system operating conditions at the recommended interval of once every four hours. If automated or more frequent monitoring is performed,

then this form should be modified by the utility.

UV Disinfection Guidance Manual M 8 June 2003 Proposal Draft Appendix M. Compliance Forms Table M. 5 Daily UV Intensity Sensor and UVT Monitoring and Compliance Log1 where, is measured intensity is measurement uncertainty Duty Sensor Reading ( A) Reference Sensor Reading ( B) Error [( A B)/ Bx100] Acceptable ( Y/ N)

alibration.

ange of tolerance.

ented below. Total Uncertainty Criteria = ( ) 2 1 2 Duty 2 Ref Ref uty D 100 *

1 I I   +

  I Reporting Period:

System/ Treatment Plant:

PWSID: Duty UV Intensity Sensor Uncertainty (%): where,

Reference Intensity Sensor Uncertainty (%): is measured intensity Total Uncertainty Criteria (%): is measurement uncertainty UVT Intensity Sensor Calibration Report ( Make Additional Copies of Form as Necessary)

Reactor/ Duty Sensor No. Reference Sensor ID Duty Sensor ID Date Time Duty Sensor Reading ( A) Reference Sensor Reading ( B) Error [( A B)/ Bx100]

Certification:

Of the ______ sensors within those reactors that operated during this reporting period, ______ have been checked for calibration.

One or more of the sensors within those reactors that operated during this reporting period were outside the acceptable range of tolerance.

UV Intensity Sensor( s) sent to manufacturer to be recalibrated as documented below.

UV intensity sensors sent to manufacturer for calibration:

Sensor ID Unit No. Date Sent Date Received Operator Signature: Date: Total Uncertainty Criteria = ( 2 Ref Ref uty D 100 *

1 I I

  I UV Disinfection Guidance Manual M 9 June 2003 Proposal Draft Appendix N. UV Lamp Breakage Issues Lamps used in UV reactors typically contain mercury or an amalgam composed of mercury and another element, such as indium or gallium. Other elements, such as xenon, cadmium, zinc, and magnesium, are also capable of generating UV light; however, the temperatures required to volatilize these elements are much higher than to volatilize mercury. In contrast, mercury has a sufficient vapor pressure at ambient temperatures to provide the optimum pressure for efficient production of resonance radiation. Moreover, mercury has a low ionization energy to facilitate starting a lamp ( Phillips 1983). In order to provide a cost efficient lamp while addressing perceived risks and disposal issues associated with mercury, lamp manufacturers are continuing to develop ways to reduce the mercury content of lamps without impacting their efficiency ( USEPA 1997b; Walitsky 2001).

The mercury contained within a UV lamp is isolated from exposure to water by a lamp envelope and surrounding lamp sleeve. In order for mercury to be released into the water, both the lamp and lamp sleeve must break. For the purposes of this appendix, lamp breakage is defined as fracture of the lamp sleeve and the lamp envelope. This is further divided into off line and on line breaks. Off line breaks occur during handling or maintenance functions when the lamps are not installed in the reactor. On line lamp breaks occur while UV reactors are in operation.

Due to the general public health concern with mercury, this appendix discusses the issues associated with UV lamps used for drinking water disinfection by addressing potential causes of lamp breakage, preventive measures, disposal issues, the fate of mercury after release, and regulatory issues.

N. 1 Off Line Lamp Breaks Off line breaks occur when a lamp breaks during shipping, handling, or storage. These releases do not pose a hazard to the water consumer but are a concern for operators or employees in the vicinity of the break.

N. 1.1 Potential Causes of Off Line Lamp Breaks and Corresponding Prevention Measures Mercury is sealed in a UV lamp within the lamp envelope; therefore, there is no risk of mercury exposure from handling an unbroken UV lamp. The UV manufacturer should train operators in proper handling and maintenance of UV lamps to avoid mishandling and potential off line breaks. In addition, proper storage procedures will also reduce the potential for lamp breakage. Lamps should be stored horizontally in individual packaging. Lamps should not be stacked unpackaged on one another or vertically propped in corners ( Dinkloh 2001a).

UV Disinfection Guidance Manual N 1 June 2003 Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 2 June 2003 N. 1.2 Off Line Mercury Release Cleanup Procedures Off line lamp breaks resulting in a release of mercury can occur; therefore, Standard Operating Procedures ( SOPs) should be developed that describe the procedures for containing and cleaning the off line spills. The local poison control center, fire department, or public health board can assist in the development of SOPs.

Small spills, defined as less than about 0.6 to 2.25 grams ( USEPA 1992) or the amount in a broken thermometer ( USEPA 1997a), can be contained and collected with commercially available mercury spill kits. Mercury and materials used during the cleanup procedure are regulated as hazardous wastes and should be disposed of properly as described in section N. 3.3. The USEPA Office of Emergency and Remedial Response recommends that "[ i] n the event of a large mercury spill ( more than a broken thermometer's worth), immediately evacuate everyone from the area, seal off the area as well as possible, and call your local authorities for assistance" ( USEPA 1997a). Local authorities can help determine the appropriate response for various spill sizes to be included in SOPs. Given that the mercury content in a single UV lamp typically ranges from 0.005 to 0.4 grams ( as discussed in section N. 4.3), large mercury spill actions would not be warranted for a single lamp break or multiple lamp breaks that result in release of less than roughly two grams.

Superfund Amendments and Reauthorization Act ( SARA) Title III regulations address emergency release, inventory, and release reporting requirements for hazardous materials. The reportable quantity for mercury spills is one pound ( 454 grams) as mercury. Based on typical mercury levels in UV lamps ( discussed in section N. 4.3), this would necessitate the breakage of approximately 1,100 medium pressure ( MP) lamps and up to 90,000 low pressure ( LP) lamps; as such, spilling more than one pound of mercury is highly unlikely.

N. 2 On Line Lamp Breaks A recent survey of domestic water and wastewater municipalities, UV lamp manufacturers, and UV reactor manufacturers identified relatively few instances of on line lamp breaks and mercury release ( Malley 2001). This section discusses potential causes of lamp breakage and corresponding prevention measures, followed by a summary of documented incidents of on line lamp breaks.

N. 2.1 Potential Causes of On Line Lamp Breaks and Corresponding Prevention Measures Lamp breaks can potentially be caused by debris in the water, temperature variations, exceeding positive or negative pressure limits ( water hammer), electrical surges, or improper maintenance. Lamps may also break as a result of inherent mechanical or physical limitations of the lamp and improper material selection.

Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 3 June 2003 N. 2.1.1 Debris Debris in the water can potentially break the lamp sleeves and lamps. Although the majority of UV reactors will be installed after the filters in the treatment train, it is possible that equipment failure upstream may release parts or fragments, such as nuts or bolts. In addition, if UV disinfection is applied prior to the filters the probability of having debris in the water might be higher compared to post filter UV installation. Ground water systems have reported stones or gravel from wells entering UV reactors and breaking lamps ( Malley 2001; Roberts 2000).

Placement of screens, baffles, or low velocity collection areas upstream of UV reactors or vertical installation of UV reactors ( when applicable) may reduce the risk of debris in the water from entering the reactor ( Cairns 2000; Malley 2001, McClean 2001b). The extent of containment provided by these safety measures is unknown. Utilities and designers should determine the applicability of these isolation techniques on a site specific basis.

N. 2.1.2 Loss of Water Flow and Temperature Considerations UV lamps are designed to operate within a specific temperature range to maximize the UV light output of the lamp. Without flowing water to cool the lamp, the lamp temperature can rise to dangerous levels and may break ( Dinkloh 2001a; Malley 2001; Srikanth 2001a; Srikanth 2001b). This overheating is more likely to occur with MP than LP lamps ( due to lamp operating temperatures) and occurs much faster in air than stagnant water. Even if upper temperature levels are not exceeded, after restoration of water flow, the lower temperature water entering the reactor may cause the lamp sleeve and the lamp to break due to temperature differentials ( Dinkloh 2001a; Malley 2001). In order to prevent lamp breaks, operating procedures should ensure that the following conditions are met:

  Water is flowing through the UV reactor if the UV lamps are energized.

  The lamps are not energized while the reactor is not flowing full ( i. e., no air in the reactor).

Temperature sensors should be, and typically are, incorporated into the reactor design and will shut down the reactor before critical temperatures are exceeded ( Cairns 2000; Dinkloh 2001a; Malley 2001; Srikanth 2001b). Proper hydraulic design is also necessary to ensure that lamps are submerged at all times during reactor operation. Reactor designs should incorporate low flow alarms, air relief valves, or other devices to ensure that lamps are operating only when the reactor is completely flooded and water is flowing. These sensors should be linked to an alarm and automatic shutoff system ( Cairns 2000; Dinkloh 2001a; Srikanth 2001b). Lamp overheating and temperature differentials could break all the lamps within the affected reactor.

N. 2.1.3 Pressure Related Issues Hydraulic pressures within the reactor that are not within UV installation operating limits may also break the lamp sleeve. Although breaking the lamp sleeve does not automatically break the lamp envelope, the lamp is more vulnerable when its lamp sleeve has been Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 4 June 2003 compromised, potentially allowing the lamp envelope to come into direct contact with the surrounding water.

Most lamp sleeves are designed to withstand continuous positive pressures of at least 120 pounds per square inch gauge ( psig) ( Roberts 2000; Aquafine 2001; Dinkloh 2001c; Srikanth 2001a; Srikanth 2001b). However, negative gauge pressures below  1.5 psig have been shown to adversely affect lamp sleeve integrity ( Dinkloh 2001c). The tolerance level of the lamp sleeve depends on the quality of the quartz and the thickness and length of the lamp sleeve; therefore, pressure thresholds vary between lamp sleeves. Positive and negative pressures, such as those associated with water hammer, that exceed these levels may compromise the integrity of the lamp sleeve. Manufacturers should provide lamp sleeves with the appropriate material, thickness, geometry, and seals for the specified pressure and flow ranges of a given UV installation. Water hammer can affect all UV reactors and break all lamps; therefore, utilities should perform a surge analysis to determine if water hammer is a potential problem.

N. 2.1.4 Procedural Errors Operation and maintenance training can help prevent lamp breaks during on line operations because a lamp damaged by off line handling or improper maintenance operations may potentially break under on line pressure or temperature stresses. For example, a common procedural error that can occur during lamp replacement is over tightening compression nuts when securing the lamp sleeve ( Aquafine 2001; Dinkloh 2001a; Srikanth 2001a; Srikanth 2001b; Swaim 2002). Over tightening can cause a fracture of the lamp sleeve or a leak around the sleeve or compression nut cavity that may not become apparent until after start up and operation of the UV reactor.

N. 2.1.5 UV Reactor Design The UV reactor manufacturer should design the UV reactor to reduce the possibility of lamp sleeve and lamp breaks. This subsection describes design problems that may cause lamp sleeve and/ or lamp breakage if not properly addressed.

Electrical Considerations If the UV installation electrical support system is improperly designed ( e. g., inadequate circuit breakers and ground fault indicator circuits), electrical surges can cause short circuiting and lamp socket damage ( Srikanth 2001a; Srikanth 2001b). In addition, system electronics that can provide voltages that exceed lamp ratings ( overdriving lamps) may also result in breaking the lamp ( Malley 2001).

Cleaning Mechanism Considerations The cleaning mechanism may break the lamp sleeve and lamp envelope if it is not aligned properly. Although the cleaning mechanism closely surrounds the lamp sleeve for cleaning, manufacturers should ensure that the mechanism is flexible and able to adjust to minor misalignment of the lamp sleeves.

Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 5 June 2003 At high lamp temperatures, the cleaning mechanism in some UV reactors may fuse to the lamp sleeve when not in use. As a result, during the next cleaning event, the lamp sleeve may crack when the cleaning mechanism is activated or when the cleaning mechanism passes back over the residual left on the lamp sleeve ( Dinkloh 2001a). Routine inspection according to manufacturers' recommendations will help detect problems with the cleaning mechanism before damage occurs. In some UV reactors, wipers rest away from the lamp sleeve when not in use and an alarm sounds when the wiper stops along the lamp sleeve.

Thermal Expansion and Contraction Other potential causes of lamp breaks include improper matching of lamp materials with respect to thermal expansion characteristics. Compatible materials within the lamp should be used by the manufacturer to avoid stress and damage that can be caused by thermal expansion and contraction differences between materials under various operating, shipping, or handling conditions ( Cairns 2000). In addition, improper seal design or lamp envelope swelling may cause water leaks around the seals that may result in electrical shorts and cracking of lamps ( Cairns 2000).

N. 2.1.6 Summary of Potential Causes and Methods of Prevention of On Line UV Lamp Breaks Table N. 1 summarizes the potential causes of on line lamp breaks and provides a brief description of the preventive measures that UV installation designers and operators can implement to reduce each risk. There are few documented cases where lamps have been broken during on line operations, which are discussed in section N. 2.2.

Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 6 June 2003 Table N. 1 Summary of Potential Causes and Methods of Prevention of On Line UV Lamp Breaks Potential Cause Description Preventive Measure Debris   Physical impact of debris on lamp sleeves may cause lamp breaks.   Installation of screens, baffles, or low velocity collection areas upstream of UV reactors or vertical installation of UV reactors will help prevent debris from entering the reactor. Loss of Water Flow and Temperature Considerations   Lamps may overheat and break.   The temperature differential between stagnant water or air and flowing water may cause lamp breaks.   Reactors should always be completely flooded. Temperature and flow sensors that are linked to an alarm and automatic shutoff system can be used to indicate irregular temperature or flow conditions. Pressure Related Considerations   Excessive positive or negative pressures may exceed lamp sleeve tolerances and break the lamp sleeve.   A surge analysis should be completed to determine the occurrence of water hammer.   Pressure relief valves or other measures can be used to reduce pressure surges.   Applicable pressure ranges should be specified for lamp sleeves. Procedural Errors   Improper handling or maintenance may compromise the integrity of the lamp sleeve and/ or lamp.   Operators and maintenance staff should be trained by the manufacturer.

UV Reactor Design   Electrical surges can cause short circuiting and lamp socket damage.   Applying power that exceeds design rating of lamps can cause lamps to burst from within.   Adequate circuit breakers/ ground fault indicators should be specified to prevent damage to the reactor.   Replacement lamps should be electrically compatible with reactor design.

  Misaligned or heat fused cleaning mechanism may break or damage the lamp sleeve and lamp envelope.   Operators and maintenance staff should perform routine inspection and maintenance according to manufacturers' recommendations.

  Thermally incompatible materials do not allow for expansion and contraction of lamp components under required temperature range.   Designers should specify temperature ranges likely to be encountered during shipping, storage, and operation of lamps to aid the manufacturer in the selection of thermally compatible materials.

N. 2.2 Frequency of On Line Lamp Breaks There have been relatively few documented incidents of on line lamp breaks. As part of a survey of domestic water and wastewater municipalities, UV lamp manufacturers, and UV reactor manufacturers, Malley ( 2001) identified nine cases of on line lamp breaks. Both the lamp sleeve and lamp envelope were damaged in all nine cases, resulting in mercury release ( Table N. 2). No cases of on line failures using LP or low pressure high output ( LPHO) lamps were identified. However, LPHO lamps are relatively new to the UV disinfection market and all LPHO lamp installations have been operating for 5 years or fewer ( Malley 2001). All nine cases involved MP lamps. Four of the nine lamp breaks were caused by impacts from stones on lamps Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 7 June 2003 oriented perpendicular to flow. In one of the nine lamp breaks, the applied power exceeded design rating of lamp ( 30kW) causing the lamp to burst from within. Differential sleeve heating resulted in two of the nine documented lamp breaks. The lamps were mounted vertically in the UV reactor allowing heat to accumulate at the top of the lamp, eventually cracking the sleeve. In two of the nine instances, operating lamps reached extremely high temperatures (> 600 ° C) in air because the reactors lost water flow. When water flow resumed, the cooler water ( 20 ° C) broke the lamps. Most of these documented cases of lamp failure were the result of design issues that have been addressed in modern reactor designs. As mentioned previously, temperature and flow alarms should shut the UV reactor down when the potential for overheating or differential heating exist.

Another documented instance of MP lamp breakage occurred in a UV peroxide reactor designed for well head treatment of tetrachloroethene contaminated ground water ( Moss 2002a). The UV reactor was positioned between the ground water extraction pump and distribution system booster pumps. The 7 foot long MP lamp sleeve sagged and came into contact with the lamp envelope. The lamp envelope and lamp sleeve broke, releasing mercury to the water in the reactor. The lamp failure triggered an alarm, shutting down both the ground water extraction and distribution system booster pumps. Mercury liquid was found settled in the bottom of the reactor. Water sampling at a nearby fire hydrant detected mercury concentrations below the maximum contaminant level ( MCL) of 2 micrograms per liter ( µ g/ L) ( Moss 2002a; Moss 2002b).

European drinking water utilities have an extensive history with UV technologies. Unfortunately, no written documentation of lamp failures was identified; however, two instances of lamp breakage during UV disinfection of drinking water were noted by European manufacturers ( Roberts 2000; Table N. 2). In one instance, a ground water well pump discharged gravel or stones into the reactor, resulting in a lamp break. A strainer was placed in line prior to the reactor to prevent any future instances. The other documented case of a lamp breaking was due to operator error. A forklift was driven into an operating reactor and physically damaged the UV reactor. The event activated an alarm and pneumatic valve closure, which contained the contamination ( Roberts 2000). In addition, there was an incident in which equipment debris ( a bolt from the filter underdrain) impacted a lamp sleeve. Although the lamp sleeve was broken, the lamp envelope remained intact and mercury was not released because of the immediate UV installation shutdown and prompt operator response ( McClean 2001a). Table N. 2 summarizes the documented lamp breakages discussed in this section.

Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 8 June 2003 Table N. 2 Mercury Release Incidents Involving UV Lamp Breaks Identified Cause Number of Incidents Description of Incident Debris 5 ( 4) 1 Stones entered the reactors and impacted and broke the lamps.

( 1) 2 Gravel entered reactor through the booster pump and impacted and broke the lamp.

Loss of Water Flow and Temperature Considerations 2 ( 2) 1 Lamps were left on and allowed to reach high temperatures ( 600 oC) in empty non operating reactors. Restoration of flow resulted in cooler water ( 20 oC) breaking the lamps.

Operator Error 1 ( 1) 3 Forklift collided with on line reactor resulting in lamp breakage.

Manufacturer Design 4 ( 1) 1 Applied power exceeded design rating of lamp ( 30kW) causing the lamp to burst from within. ( 2) 1 Vertical orientation of lamps resulted in differential heating and eventual cracking of lamp sleeve as surrounding water cooled the submerged portion of lamp and the exposed portion of the lamp accumulated heat. ( 1) 4 High operating temperatures resulted in deformation of the lamp sleeve. The lamp sleeve sagged and on contact with the lamp envelope, both envelope and lamp sleeve broke. 1 Survey of domestic water, wastewater, and hazardous waste treatment utilities ( Malley 2001) 2 European drinking water facilities ( Roberts 2000) 3 European brewery ( Roberts 2000) 4 UV peroxide ground water remediation reactor ( Moss 2002a)

N. 2.3 On Line Mercury Release Response Plan On line lamp breaks are rare occurrences that are preventable with appropriate design and operation of UV reactors. However, utilities may consider developing a mercury release response plan for an on line UV lamp break. The plan may include the following components:

  Site specific containment measures   Mercury sampling and compliance monitoring guidelines   Clean up procedures   Reporting requirements In the event of an on line lamp failure alarm, the UV reactor should be immediately shut down and operators should attempt to determine the cause of the alarm. Unfortunately, lamp failure alarms or sensors cannot typically determine the cause of the alarm, whether it is partial or complete breakage of the lamp sleeve or lamp envelope ( Kolch 2001) or another problem unrelated to the lamps. Thus, it is recommended that the reactor be taken off line when investigating the cause of a lamp failure alarm ( Kolch 2001).

Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 9 June 2003 In the event of an on line lamp break and mercury release, operators should attempt to isolate the mercury in the reactor or downstream. Utilities may install spring return actuated valves with a short closure time on the reactor inlet and outlet piping ( McClean 2001b) to isolate the mercury. Given the short residence time of many MP reactors, the outlet side valve may need to be located quite a distance downstream so that the valve has time to close and isolate the mercury upstream. UV installation designers should evaluate valve closure times with respect to creating water hammer.

Condensed mercury may collect in areas of low water velocity such as the bottom of a shutdown reactor, sump areas, or a clearwell. In addition, a strainer positioned on the reactor outlet piping may prevent lamp fragments from entering the water supply system ( McClean 2001b; Srikanth 2001a; Srikanth 2001b). The headloss associated with such measures should be considered in the hydraulic profile. Designers may also consider installation of drains, vacuum relief valves, and piping to allow disposal of potentially contaminated water in the reactor to a waste container or truck.

The extent of containment provided by these safety measures is unknown. Utilities and designers should determine the applicability of these isolation techniques on a site specific basis.

Utilities should coordinate with their State primacy agency when developing the following action items:

  Mercury sampling plan   Sampling procedures may outline sample locations, sampling frequencies, and analysis methods. Sample locations should be chosen with consideration of where mercury may settle and to assess the mercury concentrations potentially reaching the consumer. Sampling frequencies should consider flowrate, detention time, and travel time to the first potential consumer.

  Site specific cleanup procedures   Site specific cleanup procedures should be incorporated into a utility process hazard analysis ( PHA). Issues to consider are detection and disposal of isolated or condensed mercury, potential disposal or treatment of contaminated water, and cleanup responsibilities ( by utility staff or contracted hazardous materials team).

  Reporting to State   Reporting may include a description of the release, estimated quantity of release, shutdown or containment procedures, cleanup or disposal methods, sampling procedures ( including sampling locations, frequencies, and results).

  Public notification requirements, if applicable   Revised public notification requirements ( 40 CFR 141.203) outline three tiers of public notification, depending on the severity of the violation or situation. Exceeding the mercury MCL of 2 µ g/ L is classified as a Tier 2 notice, where public notification is required within 30 days, unless extended to 90 days by the State primacy agency. Public notification requirements do not specifically address mercury releases due to UV lamp breakage where the MCL is not exceeded.

Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 10 June 2003 N. 3 Regulatory Review This section presents a review of regulations that may apply to the use or breakage of UV lamps containing mercury in water treatment plants ( WTPs).

N. 3.1 Safe Drinking Water Act The Safe Drinking Water Act ( SDWA) established a primary MCL of 2 µ g/ L for inorganic mercury ( 40 CFR 141.62( b)). The required monitoring frequency depends on the water source and the frequency of detections. Utilities using ground water sources are required to sample once every 3 years. WTPs using surface water sources are required to sample annually. If mercury is detected above the MCL in any ground water or surface water utility, the utility must sample quarterly.

These regulations are independent of the use of UV disinfection at a facility. As discussed in section N. 2.3, utilities should consult with their primacy agencies when developing a sampling plan for responding to an on line UV lamp break.

N. 3.2 Operator Health and Safety  Exposure Limits The Mercury Study Report to Congress ( USEPA 1997c) provides detailed information on health effects associated with exposure to elemental mercury and mercury compounds. Mercury exposure to employees in WTPs falls under the regulatory authority of the Occupational Safety and Health Administration ( OSHA). The exposure limits set by OSHA focus on exposure by inhalation.

OSHA regulations have established permissible exposure limits ( PELs) for mercury compounds and organo alkyls containing mercury. A PEL is a time weighted average concentration for an 8 hour workday during a 40 hour work week that is not to be exceeded. When a PEL is designated as a ceiling level ( cPEL), the concentration cannot be exceeded during any part of the workday. PELs and cPELs are enforceable standards. The National Institute for Occupational Safety and Health ( NIOSH) also publishes Immediately Dangerous to Life or Health ( IDLH) concentrations for a variety of compounds. IDLH concentrations represent the maximum concentrations that one could escape within 30 minutes without symptoms of impairment or irreversible health effects. These values are not enforceable, but can be used as guidance for safety procedures. Table N. 3 outlines the PELs, cPELs, and IDLHs for mercury compounds and organo alkyls containing mercury.

Table N. 3 Health and Safety Standards for Mercury Compounds in Air Compound PEL ( mg Hg/ m3) cPEL ( mg Hg/ m3) IDLH ( mg Hg/ m3)

Mercury compounds NR 0.1 10 Organo alkyls containing mercury 0.01 0.04 2 NR  not reported.

Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 11 June 2003 In the event of a spill, the volatilization and the resultant concentration of mercury in air depends on the vapor pressure ( 0.002 mm Hg; Table N. 4), air currents, temperature, surface area/ dispersion of mercury droplets, and time. Calculations using the ideal gas law ( PV= nRT) indicate that these levels may be exceeded if cleanup of the mercury spills does not occur; however, prompt response and proper cleanup procedures should prevent exposure levels over these standards.

N. 3.3 UV Lamp Disposal Regulations Lamp manufacturers are required to determine whether their products exhibit the toxicity characteristic for mercury using a test called the Toxic Characteristic Leaching Procedure ( TCLP, 40 CFR 261). If the TCLP level of a lamp is above the regulatory limit of 0.2 mg/ L, the lamp is regulated as a universal hazardous waste ( Universal Waste Rule, 40 CFR 273) under Subtitle C of the Resource Conservation and Recovery Act ( RCRA). As such, these lamps should be sent to a mercury recycling facility where the mercury is recovered and lamp components are recycled. Although some mercury lamps do not exceed the TCLP regulatory level, utilities are encouraged to recycle these lamps to reduce mercury loading to the environment. Some UV reactor and lamp manufacturers will accept spent or broken lamps for recycling or proper disposal ( Dinkloh 2001a; Lienberger 2002; Gump 2002). Alternatively, utilities should contact their primacy agency for a list of local recycling facilities.

N. 4 Additional Factors Affecting Risk This section provides further information that may be helpful in evaluating risk associated with on line lamp breakage. The ultimate fate of mercury after a lamp is broken is currently unknown but is expected to depend on the following conditions:

  Physical and chemical properties of mercury species in air and water   Mercury behavior in operating UV lamps   Quantity of mercury released ( type, age, and number of broken lamps)

  Potential mercury reactions in water treatment plants and the distribution system N. 4.1 Physical and Chemical Properties of Mercury Mercury can exist in three oxidation states: elemental ( Hg0), mercurous ( Hg+ 1), and mercuric ( Hg+ 2). Mercury cycles between oxidation states as a function of the redox conditions of the surrounding environment and the availability of other reactive compounds.

Elemental mercury is a liquid at ambient temperature and pressure; however, given its high vapor pressure ( Table N. 4), elemental mercury is easily vaporized at ambient temperatures. Other physical and chemical properties of elemental mercury that affect its fate and transport are outlined in Table N. 4.

Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 12 June 2003 Table N. 4 Physical and Chemical Properties of Elemental Mercury ( Merck & Co., Inc. 1983)

Property Value Melting point ( oC)  38.87 Boiling point ( oC) 356.72 Density ( g/ mL at 25 oC) 13.534 Solubility ( g/ L at 25 oC) 0.061 Vapor pressure ( mm Hg at 25 oC) 0.002 1 Further information regarding mercury solubility in water can be found in Glew et al. 1971 N. 4.2 Mercury Behavior in UV Lamps It is important to characterize the quantity and form of mercury in an operating lamp because they represent the starting point for mercury dispersion, speciation, and reaction chemistry in the water system following a lamp break. However, the quantity and form of mercury placed in UV lamps typically is considered proprietary information by manufacturers because these parameters affect the efficiency, operation, and life of the lamp. In general, the form of mercury contained in a UV lamp is elemental mercury ( LP and MP) or a mercury amalgam ( LPHO). An amalgam is an alloy of elemental mercury with another metal ( typically indium in lamp applications) that can be either solid or liquid at room temperature, depending on the relative proportions of the two metals. In operating lamps, elemental mercury ( from pure or amalgamated mercury) is vaporized in the presence of an inert gas. Vapor phase mercury is excited and then ionized by the energy transfer from the excited inert gas and the supply of electrons generated from the applied voltage ( Phillips 1983). It is the transition of mercury electrons from excited state back to ground state that releases energy in the wavelength range of the UV spectrum.

The concentration of mercury in the vapor phase in LP and LPHO lamps is controlled predominantly by temperature. Manufacturers of these lamps use different methods to control or maintain the temperature of the liquid mercury or mercury amalgam to establish the desired vapor phase mercury concentrations. Methods of controlling the temperature of mercury and, consequently, the vapor pressure in LP and LPHO include using either a mercury amalgam attached to the lamp envelope ( LPHO only), a cold spot on the lamp wall, or a mercury condensation chamber located behind each electrode. At typical LP and LPHO lamp operating temperatures, mercury remains predominantly in the liquid or solid amalgam phase with a small proportion in the vapor phase.

MP lamps are dosed with elemental mercury liquid. In operating MP lamps, mercury is primarily present in the vapor phase due to high operating temperatures ( 600 to 900 oC; Table 2.1) that cause all liquid elemental mercury to volatilize ( Phillips 1983). In order to control the concentration of vapor phase mercury, manufacturers strictly control the amount of mercury dosed or added to the lamp during production. This is different from the LP and LPHO lamps where an excess of mercury is placed in the lamp and only a portion of the elemental mercury enters the vapor phase. Once elemental mercury enters the vapor phase, mercury ionization in a MP lamp occurs the same way as in LP or LPHO lamps.

Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 13 June 2003 The relative proportion of mercury in the liquid/ amalgam phase and the vapor phase becomes important when an operating lamp breaks in water. Vapor phase elemental or ionized mercury may be released as very fine particles. These particles may more readily dissolve in water as opposed to condensed liquid or amalgamated mercury that settles in low velocity areas.

In addition to these functional mercury interactions, Altena ( 2001) reported reactions of vapor phase mercury with fluorescent lamp components, such as the glass bulb, glass stems, coatings, and the emission material ( electrodes). This process results in the embedding of mercury in lamp components and the accumulation of mercury containing deposits, such as mercury oxide, on the internal lamp envelope surface. Altena ( 2001) theorized that mercury reactions with UV lamp components would be comparable to fluorescent lamps. These deposits represent approximately 2 to 15 percent of the total mercury present in a lamp as calculated from Altena ( 2001). After breakage, these deposits are available to dissolve in water; however, mercury oxide has a low solubility in water ( Merck & Co. 1983).

Figure N. 1 outlines the expected forms of mercury in an operating lamp. Note that all liquid elemental mercury will volatilize in an operating MP lamp, leaving no mercury in the liquid phase. Also, amalgams are only used in LPHO lamps.

Figure N. 1 Mercury Speciation In Operating UV Lamps N. 4.3 Quantity of Mercury in Lamps The amount of mercury in a UV reactor is a function of the type of lamp, the number of lamps in a reactor, and the number of reactors. Mercury content within lamps depends on type ( LP, LPHO, or MP), length, and power rating. Although mercury content data are specific to manufacturer and lamp, lamps with higher pressures, power ratings, and lengths typically contain more mercury. Table N. 5 summarizes the quantities of elemental mercury dosed into lamps during manufacturing according to a confidential manufacturer survey and published literature values.

Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 14 June 2003 Table N. 5 Elemental Mercury Content in UV Lamps Mercury Content ( mg per lamp) Lamp Type Electrical Power Rating ( W) Phillips ( 1983) Clear et al. ( 1994) Manufacturer Survey LP 15 70 " a single drop" 1 202 5 50 120 260 NR 263, 364 150 LPHO 400 NR 75.5 NR 1000 NR 250 NR MP 1 25 kW 1.4  14.5 mg/ cm5 NR 200 400, 0.3  7 mg/ cm length, 7.9 mg/ cm length 1 Phillips 1983 2 75 W mercury vapor lamp 3 175 W mercury vapor lamp 4 250 W mercury vapor lamp 5 mg per cm of lamp length, reported lamp lengths are 6 300 cm ( Primarc Limited 2001) NR  Not Reported N. 4.4 Quantification of Mercury in Example UV Installations This section illustrates example calculations of the amount of mercury contained in hypothetical UV installations. Two UV reactor manufacturers established design parameters for three treatment flowrates ( 0.18, 3.5, and 210 million gallons per day ( mgd)) with a specified water quality and design dose ( Table N. 6). Design parameters included the number of lamps needed to obtain a dose of 40 mJ/ cm2 and the total number of reactors for each of the three design flows. Calculations assume 50, 150, and 400 mg of mercury per LP, LPHO, and MP lamp, respectively. Utilities should use site specific UV installation information to determine quantities because mercury content varies with lamp type and manufacturer.

Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 15 June 2003 Table N. 6 Mercury Quantity in Example UV Installations1,2 Design Flow ( mgd) Average Flow ( mgd) Lamp Type Average Number of Reactors Average Number of Lamps ( per reactor) Total Hg in UV Installation3 ( g)

LP 1 2 0.1 LPHO 1 1 0.2 0.18 0.054 MP 1 1 0.4 LPHO 1 30 4.5 3.5 1.4 MP 1 4 1.6 LPHO 6 72 64.8 210 120 MP 6 7 16.8 1 UV Dose = 40 mJ/ cm2 2 Water quality criteria: UVT = 89% ( A254 = 0.05 cm 1), Turbidity = 0.1 NTU, Alkalinity = 60 mg/ L as CaCO3, Hardness = 100 mg/ L as CaCO3 3 Values given represent the amount of elemental mercury dosed in lamps during manufacturing.

N. 4.5 Fate of Mercury After Release The previous sections define the quantity and form of mercury in an operating lamp and thus define the starting point for the investigation of the fate of mercury in the water system. Unfortunately, little documentation exists on the fate of mercury in WTPs or distribution systems. The few case studies that do exist are mainly in the wastewater industry and focus primarily on removal of influent mercury by the following wastewater treatment processes:

  Primary sedimentation ( Lester 1983; Firk 1986; Balogh and Liang 1995; Goldstone et al. 1990; Oliver and Cosgrove 1974)

  Activated sludge ( Gilmour and Bloom 1995; Lester 1983; Chen et al. 1974; and Wu and Hilger 1985)

  Conventional treatment process ( Mugan 1996; Balogh and Liang 1995; Bodaly et al. 1998)

Much of the knowledge about mercury and its potential fate in water systems is derived from studies performed in natural environments. It is expected that this knowledge of mercury cycling within the natural environment can be applied to mercury dynamics within a WTP and distribution system where environmental conditions are largely controlled and remain fairly stable. However, WTPs employ a number of chemicals that are not typically found in natural environments. No studies were identified on influence and reaction of mercury with coagulants, polymers, corrosion inhibitors, ammonia, strong oxidants, and other disinfectants ( e. g., chlorine and ozone). This subsection projects mercury reactions within a WTP and distribution system based on documented mercury reactions in the natural environment.

Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 16 June 2003 N. 4.5.1 Potential Mercury Reactions in Water Treatment Plants and Distribution System Liquid phase elemental mercury is considerably denser than water ( specific gravity = 13.6; Table N. 4) and does not readily dissolve in water. Therefore, liquid elemental mercury and mercury amalgams may settle in areas of low water velocity, thereby providing an option for early containment and removal. For example, in cases where mercury was released from other water treatment equipment ( such as manometers, flow instrumentation, or pump seals), mercury was found to have condensed and settled in the clearwell. However, the amount of mercury recovered relative to the amount of mercury released is unknown ( Cotton 2002). Kolch ( 2001) monitored the mercury concentrations in a 50 liter batch reactor following the destruction of one LPHO lamp ( approximately 150 mg Hg). Mercury concentrations reached approximately 2.5 µ g/ L in water. Amalgamated mercury was found settled on the bottom at the reactor ( Dinkloh 2001b). However, it was not reported whether all the 150 mg of mercury present in the operating lamp was recovered with the amalgam or accounted for in the aqueous phase.

Also, Kolch ( 2001) did not determine whether the source of aqueous phase mercury was dissolved mercury from the amalgam or vapor phase mercury present in the lamp prior to when it was broken. This issue may become important when considering the aqueous behavior of mercury following a MP lamp break. Mercury in a MP lamp is predominantly in the vapor phase during operation. It is unknown how the vapor phase mercury will react with the water. Vapor phase elemental and ionized mercury may become very fine particles when contacting the water as opposed to liquid or amalgamated mercury that settles in low velocity areas.

Depending on the age of the lamp, mercury containing deposits, such as mercury oxide, may accumulate on the inner surface of the lamp envelope in all lamp types. Dissolution of the deposits would result in additional ionized mercury entering the water. Prompt response to a lamp break would include removal of lamp fragments; therefore, the compounds on the lamp fragments should not have the opportunity to enter the WTP.

Once in the water, aqueous ( dissolved) elemental and ionized mercury are expected to cycle between phases and oxidation states as determined by temperature, pH, organic carbon concentration, minerals and inorganic species, and dissolved oxygen level. The mercurous ion ( Hg2 + 2) is formed by the oxidation of elemental mercury or the reduction of the mercuric ion ( Hg+ 2). The mercurous ion is capable of bonding with inorganic constituents; however, it does not bind with organic compounds. Hg2 + 2 is rarely stable under typical environmental conditions and is readily reduced to Hg0 or oxidized to Hg+ 2.

Inorganic reactions involving the mercuric ion ( Hg+ 2) include binding with inorganic ligands such as chloride, hydroxide, and sulfide. Considering sulfide is present in anoxic environments, mercury sulfide ( HgS) is not expected to form in a water treatment environment. Reactions of Hg+ 2 with chloride and hydroxide resulting in mercuric chloride and mercuric hydroxide compounds depend on the pH and chloride concentrations ( Beckvar et al. 1996).

Additional discrepancies arise in the comparison of mercury reactions and fate in a drinking water environment versus the natural environment when organic carbon concentrations and existing microbial populations are considered. The mercuric ion ( Hg+ 2) is the only oxidation state of mercury capable of association with organic compounds such as phenyl and methyl Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 17 June 2003 groups. The resultant organic compounds, commonly known as methylated mercury, have different chemical, physical, and toxicological properties than inorganic mercury and offer more cause for concern due to toxicity and bioaccumulation properties ( Beckvar et al. 1996). Methylation of mercury to form methyl and dimethyl mercury is primarily a biological process involving sulfate reducing bacteria although it can also occur abiotically. The extent to which methylation occurs depends on the availability of Hg+ 2 and the presence of an appropriate microbial population. Methylation rates are higher under anoxic conditions, low pH, elevated temperatures, and high organic matter concentrations ( USEPA 1997c). Therefore, even though Hg+ 2 may be present in the water column, all of the above factors oppose the occurrence of methylation in a drinking water environment.

Another divergence of a water treatment environment from the natural environment is the presence of treatment chemicals such as coagulants, strong oxidants, polymers, corrosion inhibitors, and ammonia. Seigneur ( 1994) researched the reaction chemistry of mercury with inorganic species and strong oxidants such as chlorine and ozone in the aqueous and gas phases that are present in the atmosphere. Ionized mercury can form inorganic compounds with chloride and hydroxide ions. Depending on reactant concentrations, these compounds may be present in the aqueous phase and as solid precipitate. Also, based on reduction oxidation potentials, it is possible that the oxidation of elemental mercury would occur in the presence of chlorine and ozone, forming mercury ions and thereby increasing the solubility of elemental mercury.

Further research and investigation is necessary to determine the mechanisms of any potential mercury reactions. Figure N. 2 outlines this preliminary assessment of mercury speciation and reaction in a drinking water environment.

Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 18 June 2003 Figure N. 2 Potential Reactions of Mercury in a Drinking Water Environment ( Compounds released from a broken lamp are in boldface type.)

Mercury ( methylated and ionic) sorption to dissolved and particulate organic matter is commonly found in natural environments ( Beckvar et al. 1996; USEPA 1997c). This observation was also made in water and wastewater treatment plant studies, where mercury became incorporated into coagulant flocs and activated sludge waste, respectively ( Logsdon 1973; Gilmour and Bloom 1995; Lester 1983; Chen et al. 1974; Wu and Hilger 1985).

If UV disinfection of raw water is used and a UV lamp breaks, the mercury could potentially be removed within the WTP. Logsdon ( 1973) investigated the efficiency of mercury removal in conventional WTPs. Bench scale laboratory tests indicated that inorganic mercury was removed via coagulation, softening, adsorption on turbidity, powdered activated carbon ( PAC) adsorption, and granular activated carbon ( GAC) column adsorption.

N. 5 Summary and Conclusions The risk associated with a mercury release to the water system depends on many factors. More research is needed to close the knowledge gap that exists regarding the fate of mercury in a drinking water environment following a UV lamp break. The influence of treatment chemicals such as oxidants, disinfectants, and coagulants is largely unstudied. Likewise, dispersion and transport of mercury through a WTP and distribution system has yet to be evaluated. Although Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 19 June 2003 these issues are, at present time, largely unknown, there are procedures and actions that can be taken to reduce or mitigate mercury release caused by UV lamp breakage.

For the purposes of this appendix, lamp breakage was defined as fracture of the lamp sleeve and the lamp envelope. This was further divided into off line and on line breaks. Off line lamp breaks typically occur during storage or handling and cause small spills (< 2g). Small spills should be contained, cleaned up, and disposed of properly.

On line lamp breaks occur while the UV reactor is in operation. There have been reported incidents of on line UV lamp breaks associated with impact from debris, loss of water flow, temperature differentials, faulty electrical equipment and design, and procedural errors. However, on line lamp breaks are a rare occurrence and are largely preventable with appropriate design, operation, maintenance, and operator care. The following engineering and administrative methods have been proposed that may help prevent UV lamp breakage:

  Screens, baffles, or low velocity collection areas prior to the reactor influent to prevent entrance of debris   Temperature and flow sensors and alarms to detect critical conditions and shut the UV reactors down   Surge analysis to determine if water hammer may be a potential problem   Comprehensive training and maintenance program In the event of a mercury release, the following engineering controls are additional precautions that may aid in the containment and collection of mercury:

  Strainers and low velocity collection areas downstream of the reactor   Isolation valves activated by an alarm to attempt to isolate potentially contaminated water The extent of containment and prevention provided by these measures is unknown. Utilities and designers should consider the applicability of these isolation techniques on a sitespecific basis. Utilities should consult with their State primacy agency in the development of standard operating procedures, clean up procedures, and reporting requirements in preparation for a potential UV lamp break and mercury release. It is recommended that a utility prepare a mercury release response plan to address these issues. This plan should address compliance with the SDWA, OSHA health and safety standards, and RCRA universal waste rules. Utilities are encouraged to recycle or return all mercury containing lamps to mercury re generating facilities or the lamp manufacturer.

Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 20 June 2003 N. 6 References Aquafine Corporation. 2001. CSL Series: Installation, Maintenance, and Operation Manual Part No. 115 1.

Altena, F. W., J. B. J. van Overveld, and H. Giller. 2001. Technological advances in disinfection lamps leading to more compact UV sources. Presented at the First International Congress on Ultraviolet Technologies, Washington, DC, June 14 16.

Balogh, S. and L. Liang. 1995. Mercury pathways in municipal wastewater treatment plants. Water, Air, and Soil Pollution 80: 1181 1190.

Beckvar, N., J. Field, S. Salazar, and R. Hoff. 1996. Contaminants in aquatic habitats at hazardous waste site: mercury. Hazardous Materials Response and Assessment Division of the National Oceanic and Atmospheric Administration Technical Memorandum NOS ORCA 100. Seattle, WA.

Bodaly, R. A., J. W. M. Rudd, and R. J. Flett. 1998. Effect of urban sewage treatment on total and methyl mercury concentrations in effluents. Biogeochemistry 40: 279 291.

Cairns, B. 2000. Comments on USEPA questions about the risk of using UV disinfection technologies in the potable water industry. Trojan Technologies Inc., London, Ontario, Canada, May 24.

Chen, K. Y., C. S. Young and N. Rohatgi. 1974. Trace metals in wastewater effluents. J. Water Poll. Control Fed. 46: 2663.

Clear, R., and S. Berman. 1994. Environmental and health aspects of lighting: mercury. Journal of the Illuminating Engineering Society 138 156.

Cotton, C. 2002. Confidential communication with major water municipality. June.

Dinkloh, L. 2001a. Wedeco Ideal Horizons. Personal communication with Jennifer Hafer, Malcolm Pirnie, regarding UV reactors. Tucson AZ, May 10.

Dinkloh, L. 2001b. Wedeco Ideal Horizons. Personal communication with Jennifer Hafer, Malcolm Pirnie, regarding UV reactors. Tucson AZ, August 10.

Dinkloh, L. 2001c. Wedeco Ideal Horizons. Email to Christine Cotton regarding UV negative pressure. Tucson AZ, August 15.

Firk, W. 1986. Heavy metals in sewage and occurring sludges   the balance of three sewage treatment plants, edited by J. N. Lester, R. Perry and R. M Sterritt. Lisbon: International Conference Chemicals in the Environment.

Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 21 June 2003 Gilmour, C. C. and N. S. Bloom. 1995. A case study of mercury and methylmercury dynamics in a Hg contaminated municipal wastewater treatment plant. Water Air and Soil Pollution 80: 799 803.

Glew, D. N. and D. A. Hames. 1971. Aqueous nonelectrolyte solution: mercury solubility in water. Canadian Journal of Chemistry 49: 3114 3118.

Goldstone, M. E., C. Atkinson, P. W. W. Kirk, and J. N. Lester. 1990. The behavior of heavy metals during wastewater treatment III: mercury and arsenic. The Science of the Total Environment 95: 271 294.

Gump, D. 2002. Severn Trent. Personal communication with Jennifer Hafer, Malcolm Pirnie, Inc., regarding UV reactors. Tucson AZ, November 6.

Kolch, A. 2001. Assessing the risk of mercury release from ultraviolet discharge lamps in drinking water. Wedeco AG Water Technology.

Lester, J. N. 1983. Significance and behaviour of heavy metals in waste water treatment processes. I. sewage treatment and effluent discharge. Science of the Total Environment 30: 1 44.

Lienberger, J. 2002. Trojan Technologies. Personal communication with Jennifer Hafer, Malcolm Pirnie, Inc, regarding UV reactors. November 5.

Logsdon, G. and J. Symons. 1973. Mercury removal by conventional water treatment techniques. Journal American Water Works Association 554 562.

Malley, J. 2001. Addressing concerns over mercury releases from UV lamps. IUVA News 3, no 3: 28 29.

McClean, J. 2001a. Hanovia Corporation. Personal communication with Doug Owen and Christine Cotton, Malcolm Pirnie, Inc., regarding UV reactors. Slough, England, April 9.

McClean, J. 2001b. Hanovia Corporation. Response to memo by Christine Cotton, Malcolm Pirnie, Inc., regarding UV reactors. Tucson AZ, May 4.

Merck & Co., Inc. 1983. The Merck Index 10th Edition, edited by M. Windholz. Rahway, NJ.

Moss, L. 2002a. Personal communication with Jennifer Hafer, Malcolm Pirnie, Inc., regarding UV reactors. Tucson AZ, April 29.

Moss, L. 2002b. Personal communication with Jennifer Hafer, Malcolm Pirnie, Inc., regarding UV reactors. Tucson AZ, November 18.

Mugan, T. J. 1996. Quantification of total mercury discharges from publicly owned treatment works to Wisconsin surface waters. Water Environment Research 68: 2, 229 234.

Proposal Draft Appendix N. UV Lamp Breakage Issues UV Disinfection Guidance Manual N 22 June 2003 Oliver, B. G., and E. G. Cosgrove. 1974. Efficiency of heavy metal removal by a conventional activated sludge treatment plant. Water Research 8, no 11: 869 874.

Phillips, R. 1983. Sources and Applications of Ultraviolet Radiation. Academic Press Inc., New York, New York.

Primarc Limited. 2001. September 5,. www. primarc. com.

Roberts, A. 2000. Hanovia Corporation. Letter to Dan Schmelling, EPA. April 10.

Seigneur, C., J. Wrobel, and E. Constantinou. 1994. A chemical kinetic mechanism for atmospheric inorganic mercury. Environmental Science and Technology 28: 1589 1597.

Srikanth, B. 2001a. Aquafine Corporation. Letter to James Malley, UNH, regarding accidental UV lamp breakage and potential scenarios and prevention strategies. June 13.

Srikanth, B. 2001b. Aquafine Corporation. Personal communication with Jennifer Hafer, Malcolm Pirnie, Inc., regarding UV reactors. Tucson, AZ, June 21.

Swaim, P. D., M. A. Morine, R. G. Brauer, M. A. Neher, J. L. Gebhart, and W. D. Bellamy. 2002. Operating data from Henderson's full scale UV disinfection facility. Proceedings from the Water Quality Technology Conference, November 10 14, Seattle, WA.

U. S. Environmental Protection Agency. 1992. Characterization of Products Containing Mercury in Municipal Solid Waste in the United States, 1970 2000. Office of Solid Waste, Washington, D. C.

U. S. Environmental Protection Agency. 1997a. Mercury  Emergency Spill & Release Facts. EPA 540 K 97 004, OSWER 9378.0 10FS, PB97 963405. Office of Emergency and Remedial Response, Washington, D. C.

U. S. Environmental Protection Agency. 1997b. Mercury emissions from the disposal of fluorescent lamps. Office of Solid Waste, Washington, D. C. June 30.

U. S. Environmental Protection Agency. 1997c. Mercury Study Report to Congress. EPA 425/ R 97 004: 2 14. Office of Air Quality Planning and Standards and Office of Research and Development, Washington, D. C.

Walitsky, P. Philips Lighting. 2001. Personal communication with Jennifer Hafer, Malcolm Pirnie, Inc., regarding UV reactors. Tucson AZ, May 14.

Wu, J. S. and H. Hilger. 1985. Chemodynamic behavior of mercury in activated sludge process. Am. Inst. Chem. Eng. 81: 109.

Proposal Draft Appendix O. Case Studies This appendix will be included in the final draft when more information is available.

UV Disinfection Guidance Manual O 1 June 2003 Proposal Draft Appendix P. Validation Protocol Calculator Tool The validation protocol described in Chapter 4 and Appendix C of this guidance manual involves several calculations to determine the log inactivation credit achieved during validation of a UV reactor. For this protocol, a safety factor calculated from uncertainties and known variability associated with UV reactors, monitoring, and validation methods is used to relate the reduction equivalent dose ( RED) demonstrated during validation to the UV dose required to achieve a specified log inactivation credit ( Table 1.4). EPA developed a spreadsheet that enables a user to input information associated with the uncertainty of validation and monitoring and calculate the safety factor and resulting target RED. The calculator was used to develop Tier 1 RED targets and can be used to apply the Tier 2 approach. ( See section C. 4.10.2 for a description of the Tier 2 approach, including the safety factor calculation.)

The Microsoft Excel ® spreadsheet contains the following five worksheets:

  Instructions   provides step by step instructions for entering data into the " RED Bias", " Polychromatic Bias", and " Safety Factor" worksheets and executing macros to calculate safety factor and resulting target RED.

  RED Bias   calculates RED bias from input of Chapter 1 UV dose requirements and inactivation and RED measured during validation.

  Polychromatic Bias   calculates the polychromatic bias for medium pressure UV systems using spectral data on the lamp output, sleeve UV transmittance, water UV transmittance, and sensor response.

  Safety Factor   calculates safety factor from RED bias, polychromatic bias, and expanded uncertainty associated with reactor validation and monitoring.

  Default Data   contains assumed data for calculating the polychromatic bias; alternatively, the user can provide validation testing data as specified in the instruction worksheet.

UV Disinfection Guidance Manual P 1 June 2003 Proposal Draft