Ladies and gentlemen, welcome to the Private Property Podcast. I am your guest host this evening. My name is Hethi the Entrepreneur and I am super, super excited for this particular episode. And I must admit it's something that I am super interested in. We are talking about home improvements and DIY. So this is going to be absolutely fantastic. And I am joined this evening by Graham Steen, who is the COO of Candua.com. So I am really in good company this evening. And as a person who's currently undergoing some home renovations myself, I cannot wait to pick his brain. So very warm welcome to you. Let's sign the register, shall we? Let me know your name and where you are joining from. Let me know your name and where you're joining from within the comment section. This is the Private Property Podcast. And if you are already enjoying the show, then you're going to love some of our other shows that we host here on the Private Property page. We've got the Home Shoppers Show by Chad. We've got the First Time Home Buyer Show with Estee, as well as the Farming Podcast with Mbali Norku. So we have a show every single weekday evening at 8pm. And this is all for your viewing pleasure. So a very, very warm welcome to you this evening. I'm very, very excited for this evening's show. I see we've got Olavine who is joining us from Durban Case it in. Menzi, I see you. Good evening. And a very, very warm welcome to you. Glad to surrender. Familiar face. Lovely to see you. And thank you for joining us this evening. Good evening, Ayetu. Thank you for signing the register. And Hoso Shumelo. Good evening to you too. This is going to be a fantastic jam packed show. And I cannot wait to pick Graham's brain. So without much further ado, a very warm welcome to you, Graham. And which part of the country are you joining us from this evening? Hi, Esi. Great to meet you. Thanks for having me and hi to all your viewers. Yeah, I'm actually currently sitting in pretty warm jogging at the moment. So great to be here. That is absolutely fantastic. We've been having some warm weather and a cool down with some rain and thundershowers, which was very, very much welcomed. So this evening, we are talking about home improvements and DIY. Now I would imagine that the trend within this particular industry has seen some changes over the last 18 months, given the fact that we are spending more time at home. What is the current home improvements based looking like in South Africa? Sure. Yeah, we've actually seen amazing, amazing things happening. And just to kind of put myself in context and why I can talk about this. So CEO of Kandura, and basically what we do is we connect contractors or what we call service providers to homeowners or customers. So people who really want to get work done in their home come to us and come to our marketplace to find good quality contractors. And what we've found since the beginning of unfortunately the beginning of the pandemic, now two years ago, I can't believe it, but really since the lockdowns opened, we saw about a 700% growth in the number of jobs coming through our platform. I know it's a very big number. And a lot of those are coming from renovations, big renovations but also small renovations. And when we speak to our customers as you said, when you're sitting around, you're sitting in your home all day, you start to find the things that you want to make changes to and you're also not spending your money on other things. So we've seen huge growth in this area. Wow, that is absolutely fantastic. I see we've got quite a number of people that are joining us all across the country this evening. We've got Pooza who's joining us from Emondi. We have got Celani Pillay who is a regular, always fantastic to see you Celani. We have got Menzi who's here and Abeda who is here as well. Now one of the things that comes to renovations and home improvements is that we often rely on doing these things ourselves. And the danger of course with that is that we're subject to all kinds of myths when it comes to home improvement. First and foremost, let me just put you on the line here Graham and ask you, should we be doing our home renovations ourselves? Definitely not. So DIY can be do it yourself but it can also be damaged yourself. So we've seen numerous times where people have gone in to try and DIY a renovation. And unfortunately if you haven't done it before, if you're not trained, you can cause a lot more damage than you initially planned or budgeted for. So you end up spending twice. So we always recommend that if you're doing a renovation or doing some work at home, rather bring in a professional and let them do the job properly and do it once. That sounds like some sound advice to me. And speaking of budgets, when a person is budgeting, is it better to kind of overspend thereby appreciating the value of your property or should one actually be a little bit more cautious about not spending too much with their renovation projects? That's a great question. So another of what we kind of miss that we see is that really the money you put into your property is the money you get directly out. And unfortunately that's not always the answer.  It's really about spending wisely. So when you're looking to go into your property and you start to do renovations, your best bang for buck is always going to be kind of your kitchen or your bathroom, right? If you're really looking to sell a house, that's where you're going to get your money back. And even then to be honest, you should still budget to only be getting about 70 to 80 percent of the value that you spend back in the increased value in your home. So it's really important not just to overspend and think that that's going to increase the value of your home. The other part that is really important that people don't always think about is kind of over capitalizing your home. And what this means is that when you are spending money on your home, there's generally a feeling that gets hit based on the area that you're in and the current value of your home. So if you are going to be spending, our rule of thumb is you shouldn't be 10 to 25 percent. If you're spending any more than that, you really should be rethinking how much you're spending. And even then, you should be looking at the homes around you and say, okay, what is the average selling price of the property? And where do I think my home is going to be after this? Because unfortunately what we've often seen is people throwing a lot of money at a house, but ultimately, because of the area they're in, not being able to recoup that when they try and sell it later on. Very, very valuable advice that you're giving us there, Graeme. And I see that Vanessa Nell within the comment section is in very, very firm agreement with you. Now, I know most people are probably like me. When we're looking at home improvements, we go on to Google, we go on to Pinterest, and we see all of these fabulous trends. Should we really be renovating based on trends? What are the pros and cons of that? Yeah, again, it's a very interesting one. And just like you said, I'm also going through, through a renovation. So I'm experiencing that.  And what we see with trends is it's something you just have to be very wary of. Obviously, we all want beautiful homes, and there's certain things that we want. But again, when you start thinking, am I going to recoup this value, there are already two different things that can hit you. So the first one is, if you step into a home that was built in the 80s, you know it was built in the 80s. Well, if it was on trend. So understanding that what is trendy today won't necessarily be trendy in 10 years or even five years with the rates we're going. So that extra money that you spend might not be recouped is super, super important. And secondly, things that are on trend today generally have a premium for that trend. So black taps at the moment are very, very trendy. You're going to be paying about a 30% premium on that. And really, when you look at a Chrome tap versus a black tap, and I know it's getting to detail, but do you really want to spend 30% more because it can add up if you're doing a whole home. So thinking about those trends and really being very wary of what the implications can be further down the line. Absolutely, that is so true. What is cool today is not necessarily cool in five years time. And when you're in a home and having to look at a bad decision every single day, you can certainly regret your decision. Private property spam. We really wish to thank you for your loyalty to this beautiful community that we built because of your constant engagement. We have reached 1 million followers. Now that is no small feat and certainly wouldn't have been obtainable without your loyal support. So we really do thank you. If you head over to our Facebook page, you'll see that the very first post at the top is pinned at the very, very top. Go ahead, share it and let us make our Circle Pro so much bigger. We really do appreciate you. Now Graham, when we are looking at home renovations and we are also looking at the types of areas that we want to renovate, are things like swimming pools really adding that much more value to our properties? Or is that a myth? Yeah, that's a big one. It's a big one in Alaska as well. And it's a very heartbreaking one, right? Because we all, well, a lot of us love swimming pools and it's generally quite a big expense. So naturally what we think as well, if I put in a pool, I mean, that's definitely going to increase the value of my home. And unfortunately, that isn't that not true. Often what we actually see is that a swimming pool can decrease the value of a home. Why is that? Because sometimes it decreases your pool of buyers, because some people look at a pool and the first thing is they think liability, right? Or I have very small kids, I don't want to go there. And we actually see people sometimes buying a home and spending a lot of money filling in that pool. So again, I'm not saying don't don't build a pool. But I am saying that if you're building a pool just to try increase the value of your home, you're unlikely going to be able to recruit that. Fantastic. I see Menzee is asking within the comment section, what should the average spend a person should be looking at when it comes to installing burglar bars? They've been given quite a high quote. And I would imagine that this is something that can do it.com would be able to assist Menzee with. Am I right? Yeah, you definitely are right. So yeah, it can do it. We have 100 different services across the whole country. So we do everything from flammers, electricians, builders, architects, all the way through to mobile beauty, if that's something that you're interested in. And burglar bars, again, it might not be the ideal answer, but it's kind of like how long is the length of the string. So when you are installing burglar bars, you really can go for the top of the range where it's clear burglar bars, or you can go for something a little bit cheaper. My advice on that is, again, thinking about your home value. Ultimately, you're likely to, if you're looking to increase the value of your home, if you go top of the range, you probably won't always recoup that value back. So the average spend could be anything, but really look at the value of home and think about how many winners I'm going to do, and what am I going to be recouping back from that spend? Fantastic. I think that is a great answer to Menzee's question. Private property fam. Now, you know that our grand prize and competition is standing at 1,500 grand. That is nothing to sneeze at. Let me know in the comment section what you would do with 1,500 grand. Let me know within the comment section what you would do with 1,500 grand. Now, Graham, when it comes to home renovations, we've all been there before, going out there trying to look for a service provider. You don't have a way of vetting them. You don't know if they're actually going to do the job satisfactorily. But what Candua has done is actually set up a marketplace that allows service providers and people looking for services to actually be able to meet together. Can you tell us a little bit more about this process? Of course. And I guess, really, just to think of what the founding vision of Candua, why does Candua exist? Why did we make it exist? What we saw is that you had homeowners on one side who are going through what generally is, if you're doing a renovation, but any kind of work is a relatively stressful process. And it's been really, really hard for them to easily find quality service providers. It's often through word of mouth, or you might have used someone before who did your tiling, so you're like, oh, well, maybe I can bring them in and they can do my carpentry, which is not really how it works. You have specialists in each area. And then what we saw on the other side, which is also a little bit disheartening when we started, was you see these amazing service providers who do amazing work, but they weren't able to find the work or the homeowners. So you had qualified electricians, qualified plumbers, amazing carpenters who just didn't know where to find these homeowners. They potentially weren't in those word of mouth groups. So what we said is, why can't we just bring those two together? And ultimately, what brings those two together is trust. So we can do a sit in the middle to make sure that there's trust in this marketplace. So how do we do that is, on the service provider side, every service provider that comes into our platform, and we now have 30,000 service providers across the country, goes through a vetting process. So from criminal record checks all the way through, which is probably the most important, to customer reviews. So service providers provide us with reviews from previous customers, we phone them, we speak to them, we say, okay, what is the work that was done? Were you happy with the work? Not only on quality, but on timeliness, on pricing and all of that. And then each service provider gets a page on kandua.com. So you can go and read the 100 reviews on a service provider that there is a person for me. Because there is sometimes a balance between someone who might be a little bit more expensive, but has a five out of five stars, or someone who's cheaper and has four out of five stars. A little bit like all the other marketplaces, and one of the ones that drives you around, there's a certain level where if you get too low, then the service writers are removed from our market. So that really solves the, do we have quality contractors? The answer is yes. And then the other side is contractors spend a lot of time and money finding homeowners. So what we've done is, if you go on to kandua.com, we have a process that you go through to really understand the work that you need to be done. So we will, for example, if you need a Sir Legiza installed, we will ask a number of questions that we've set up to really understand what that work is. So a service provider can look at that and say, you know what, this is a job for me, I'm going to get in touch with this person, because again, and I'm sorry, this was a very long speech, but again, there's a service writers who specialize in different areas. So we need to help them find those jobs so you get the right person for you. Ah, fantastic. Sounds like a win-win situation and definitely provides peace of mind, especially by way of the bidding process, which is absolutely fantastic. I see Nkateko is saying that Nkateko would buy two buckets of paint with 1500 rand. Nkateko, it sounds like you're looking to do some home renovations. You might want to head over to kandua.com. So Graham, when it comes to identifying a service provider, now you've spotted them, you've been onto their page, you've read the reviews, and you've decided to make use of their services. What are some of the relationship must-haves and do's that one should establish with a service provider to ensure that both sides' expectations are managed? Yeah, it's a very, very important question. Thank you for asking about Hedgie. And I think the setting back a little bit, and the most important, and it's almost the myth that we have, is work is unfortunately not ever easy. It's not quick and easy. So just understanding that especially a renovation is the start of a process that's going to take time is important in the first step. And then really you're going to be establishing a relationship, a very close relationship with this person for potentially the next, if they're doing a big renovation, the next six months. So what you need to do is first, when you obviously read through all the reviews of the service provider and understand that they can do the work that you want them to do. But then what we always advise is meet with a few service providers, right? Don't just go with one. So what Candua does is we put you in touch with up to five different contractors, and you can speak to each one of them and understand whether they understand your vision. Because ultimately it's their job to realize your vision. So you should have a conversation with them, talk them through what work you want done. And ultimately, they will come to you with different ideas. Because they will have done this, you will probably be doing it for the first time. They will have done it 50 times and say, I know you and I know you wanted to do this, but how do you sort of it this way? And generally you'll feel that kind of that click. So that, so if you feel comfortable with that person and they're able to do the work, that's super, super important. Then obviously, when we get into different areas such as electricians or plumbers, you should always ask them for their qualifications or their certifications. So you need to, or gas, of course, if you need someone coming in, they need to have the right certifications, just because you need to be comfortable that they can do that work. And one final thing on this, and I think I've mentioned it three times, but it's always good to keep saying it, is that a contractor generally they specialize in different things. And we don't always understand this because we don't work in the business, but someone who is good at doing carpentry isn't necessarily good at doing tiling. So you need to say, if you want a tiling job done, you should make sure that they have pictures and they have reviews of tiling. They might have 100 great reviews of doing carpentry, but that's a completely different service. So just because it's with your hands doesn't mean it's the same thing. Wow, goodness. This has really been quite highly informative. Thank you so much for that, Graham.  Thank you so much for giving 200 stars to private property. Remember, private property family, you can support us by giving us some stars within the comment section. Now we've reached that time of the night and I know you know what time that is. It is time to find out this evening's winner. Now the amount is rolled over to 1,500 rand. Could it be going to you? Let's find out by rolling the random selector. And our winner this evening is Nombu Melelongovou. Nombu Melelongovou, a very, very big congratulations to you. As you can see, it pays to be part of the private property family. Now Nombu Melelongovou, all you need to do to claim your prize is simply to leave a comment in the comment section for us to know that you are live with us this evening. Let me know in the comment section, Pam. Do you think Nombu Melelongovou is here with us? Let us call her out. Call her if you know her. Let's ensure that she claims her prize this evening. 1,500 rand is not bad. I see some people want to buy buckets of paint and others want to go on holiday. So let's find out and see if Nombu Melelongovou is here. All you have to do is leave a comment within the comment section in order to claim your prize. All right, Graham. So talking and going back to renovations and DIY. You know, there's some problems within a house that I sometimes wonder if it really can actually be fixed or if it's probably worthwhile to just start all over again. What is your view on that? In terms of, I think there's always going to be a time where again, we just not professionals, right? So what I would say is that often there are things that you don't realize that can be fixed that could be fixed if you just get in the right professional. So always kind of beating on the same drum, but always bringing someone who really knows what they're doing. And if you have this problem or if you have an electrical fault, bring an electrician and tell them kind of also your difficulties in the budget that you have, because often there are different fixes that can be done depending on ultimately what you want to get. So and a good example of this is we also have appliance repair pros on our platform. And I happen to have my dishwasher and my washing machine break at the same time, which is always great. And the service provider came in and he looked at me and said, well, you know, to be honest, there is a lot that's broken in here. I can fix it for you, but it will probably only last you another year, right? So they're having an honest conversation with him. They said, otherwise you can replace it. And I said, well, another year buys me good time, fixes for me, I completely understand. And then when we get that year, hopefully I'll have saved enough money to replace that appliance. So it's really, you can be a little bit either or just having that honest conversation with a professional and saying, well, what can be done with this? Absolutely. Just getting that professional advice and review really does actually go a long way or lets you know how much more shelf life the actual appliance or home renovation has that can actually buy you some time. So as a way to recap Graham, please just refresh us in terms of the range of services that are provided by contractors on can do it.com. Of course. Well, as I said, there are 100 different services that will be here for a while for when through all of them. But really, what it is anything that can be done in the home. And starting from all of your anything that's connected to kind of renovations or so painting, builders, electricians, plumbers, carpenters, and all the way through. So you can also find architects, literally anything that centers around the home, you can find that can do it. And I would be surprised if you if you looked for it and you wouldn't be able to find it. Wow, that's absolutely fantastic. I just love the concept so much, especially when it comes to just alleviating one's stress and anxiety around renovating their home. I'm interested to find out Ray and when it comes to like major home renovations, perhaps in the kitchen or the bathroom. And what are some of the things that one can do to ensure that the process and the length of time to do the renovation isn't unnecessarily lengthened, you hear these horror stories of someone who says, Oh, I'm just doing some minor renovations. And then 16 months later, they're pulling their hair out. How do we avoid situations like that? Yeah, that's very important. There are a number of ways that we can do it. I know it's something that scares everyone before the beginning of a renovation. So really, there are a few things that you need to do just to make sure that you have the right quality. So ultimately, whenever you're doing a larger innovation, it is tempting to try and make trade-offs in terms of saving the odd ran here and there. And what I would say is always make sure you're getting quality material and quality service providers. Why that saves you is because if you have any problems that can really delay the work that gets done. And I can do actually what we found an interesting data point is generally, even when you have the quality service providers through our platform, they do come in about 30% less. And then also what's really important is budgeting. And I don't think I went on enough in the first myth is that your budget needs to have some wiggle room in it. If you have 100,000 round to spend and you plan for 100,000 round kitchen, you're going to be in trouble. You really need to have about 10% leeway for any unforeseen costs or breakages. And again, if you don't do that, that can really lengthen the time of your renovation because you just can't afford to ultimately pay for that kitchen. And then finally, it's what I mentioned, just find the right contractor and align on your vision because if you and align upfront, because what increases budget and increases time is any changes that get made during the build. So you really need to say, this is what I'm going to do. Once you put the pen down, that is what's going to be built. And if you have a good contractor and someone that sees your vision, they'll be honest with you and say, well, this is going to be best case, a three-month job, worst case, a six-month job, but you know it's not going to be a nine-month job. Fantastic. This has been such a highly informative session. And I see Boucher in the comment section agrees with us. Thank you so much, Boucher.  Thank you for imparting knowledge with us. It's been really fascinating to hear about the myths and debunking some of them that comes to home renovations and DIY. Very informative indeed. Thank you, Graham Steen, COOofcandua.com. All right, private property fan, it seems that Nonpo Melelo has not claimed her prize this evening. That means that we are going to have a roll over. Now that is sad for Nonpo Melelo, but it could be good news for you. Perhaps you will be the next winner. Now this brings us to the end of the show. I have had an absolutely fantastic time. And if this has been interesting, then you certainly want to stick around for 8 p.m., where we have the farming podcast with Mbali Norku. Now on that note, private property family, my name is Hetty, the entrepreneur, and I am signing out.


All we could say about the rail riders is, wow, rail riders and what they did today. Tie-breaking game against the Syracuse Mets. They were down six to one. They bring in Davey Garcia for three shutout innings of relief, and the bottom of the seventh, Kyle Higashioka, leads off the frame. 19th homer of his minor league season, first of a five-run inning for Scranton. But then the Mets answer with a six-run frame, so Higgy gets after it again. He's going to spark another rally against Nagosik. He sends the first pitch to the bottom of the eighth, the straightaway center. His second homer, Bob, they're still down 13 to seven at this point. I'm going to change that. They battle back single, sack flies, and then in the eighth, Eric Kratz doubling to the warning track in the left center. Two runs, scored a cap and eight-run inning. Jack, suddenly it's 14-13. They just have to close it out. And one of the guys who scored was pinch runner extraordinaire Terence Gore. It's Ben Heller coming in. He works a clean ninth, gets Alcantara to ground out a second, and the rail riders defeat Syracuse 14 to three in the International League North tiebreaker game. What a comeback.


We've known about painful apthas ulcers, canker sores. For thousands of years, the most common lesion of the lining of our mouths, named perhaps by Hippocrates himself. Well, what did he prescribe for it?  Though, beat to the punch by a few millennia by the ancient Egyptians on that score, also known by the ancient Chinese, the oldest wound dressing known to humankind. Well, how about a few thousand-year update? Evidently, honey has been successfully used as a treatment of a number of types of wounds, including chronic ulcers. The evidence is apparently strongest for burns. Yeah, but okay, compared to what? Compared to a boiled potato peel? I'm not making that up. Apparently, honey works twice as good as boiled potato peel dressings, perhaps because of an antibacterial effect, whereas the potato peels only seem to kind of cover things up, like slapping on cadaver skin. Ew, maybe y'all stick to the potatoes. But what else are you going to do in a resource-poor country? Here we have antibiotics to fight infection, so quality of healing is often more defined as the aesthetic look of the resulting scar. So plastic surgery patients had half of their surgical scar covered with conventional dressings, and the other half of the same scar covered in a honey dressing. And the halves of the scars covered in honey healed about a third narrower than those covered conventionally, suggesting an improvement in the healing process. Okay, but what about canker sores? Here they report 19 cases. It started out with severe pain, but evidently one day after rubbing honey on the sore, the pain was reduced drastically. In fact, gone in 92% of patients, and in most cases the ulcer was gone completely by day 3 or 4. Okay, but there was no control group. Maybe they would have gotten better anyway. Maybe there was a placebo effect. Yeah, modern medicine has neglected honey as a therapeutic agent because the science was poor, essentially a series of published anecdotes. But look, one could argue that there's never been any significant side effects associated with the topical application of honey, so lots to lose. I sympathize with that logic, but would really like to see it put to the test. But there hasn't been any good studies until this one, a randomized controlled trial honey tested head-to-head against a steroid gel against canker sores. There's all sorts of things doctors can prescribe for canker sores, topical agents like steroids and antibiotics, systemic medications, even laser therapy. But look, why not seek out the least toxic agent first? May not be the most profitable, but why not start with the safest? So they randomized folks with canker sores into one of three groups where they applied, with a Q-tip three times a day after meals, either an over-the-counter soothing pain-relieving paste or a prescription steroid cream or just plain commercial honey directly onto the canker sore. Here's what happened. Here are the pain scores. On the over-the-counter stuff, the pain was cut in half by day 4 and gone by day 8. On the prescription steroids, half by just two days and gone by 4. What about the honey group? Remember the series of cases that claimed a total pain relief in one day? Well, it was put to the test and total pain relief within one day. That's crazy. Pain for a week or just pain for a day. And honey is like 500 times cheaper. What about ulcer size? Mostly gone by 8 days, 7 days, or 3 days, and cut in half in just one day as opposed to 3 or 4 days. Here's a before and after. Day 1, massive canker sore, but dab a little honey on three times a day, and day 1, 2, and gone day 3. So a significant acceleration of healing and resolution of pain all without systemic side effects, or local side effects, for that matter, whereas the topical antibiotics that are sometimes used can have a variety of side effects. And the nice thing about honey is that it doesn't lead to the development of antibiotic resistance. Now, this was a single blind study, meaning the person evaluating the lesions didn't know which group someone was in, but the patient surely knew, as honey would have had a very different taste and texture. And evidently, the prophet Muhammad was a big fan of honey, and this study was done in Saudi Arabia, and so it's possible there was some bias, but given the extraordinary results, one might want to give it a try. Now, the benefits of honey may be due in part to the phytonutrients from the flowers the bee is making the honey from, so why not try the flowers directly? A chamomile extract appeared to cut pain in half within 10 minutes of application, but they didn't fall them out in terms of healing. But a 2% lavender oil and glycerin solution, two drops three times a day, also had an immediate effect on pain and, more importantly, seemed to accelerate healing, wiping out the ulcers by day 4 with pain diminishing in a day or two compared to over a week in the placebo group. However, you choose to treat your canker source if you keep getting them. You should see a medical professional to make sure it's not some sign of an underlying disease. There are a number of conditions that can manifest with chronic canker-sore-type lesions, like inflammatory bowel diseases or acute necrotizing ulcerative gingivitis. I think I'd rather have something like sweet syndrome or even better, magic syndrome. Who wouldn't want to have magic syndrome? Anyone, I guess, who doesn't want genital ulcers? I think I'll stay a muggle.


In a moment, he'll be bleeding. Tonight, he'll be in hospital. And next month, he'll still be struggling to walk. Five minutes ago, they could have done something to stop it. Oi! It's your choice.


This paper presents an optimized method for scheduling big data in social networks, which takes into account conflicting target data in the same data node and each tasks amount of data communication during transmission to construct a big data scheduling model. The model uses a periodic task distribution function and schedules tasks based on minimizing resource level and execution time, resulting in efficient scheduling that quickly optimizes social network data and resolves strong data collision issues. This article was authored by Weina Fu, Shuai Lu and Gautam Srivastava.


In the last few classes, we have been looking at optoelectronic devices. We first looked at devices where we have an input electrical current and convert that into light. So, we looked at two of those devices, LEDs and lasers. In both cases, we have electrons and holes that are injected into your semiconductor device. A typical example would be a P and junction and we found that these electrons and holes can recombine in order to give you light. So, now we are going to look at a different class of devices where we shine light on to the device and then measure the electric current. So, we are still looking at optoelectronic devices, but we are looking at devices where we convert light into an electrical signal. We are going to look at two such devices. The first one is a photo detector and then later we are going to look at a solar cell. So, today we will start by looking at the photo detector and as the name implies, it basically detects incident photons or radiation and then tomorrow we will look at the solar cell. So, there are three steps involved when we think about shining light on to your device and then converting it into electrical current. So, in the first case your incident light generates carriers in the device. So, when we talk about carriers, these are your electron hole pairs. Once these carriers are generated, they need to be transported to the respective electrodes. Sometimes some sort of carrier multiplication is also possible. So, you have both carrier transport and multiplication. Multiplication is usually called the gain. We will see gain in a minute and then finally, these carriers are then extracted out of the device in the form of a current. When we look at a photo detector, there are normally two classes of photo detectors. So, the first class are thermal detectors. In this particular case, you shine light on to the device or you shine light on to the material which leads to a temperature rise which is measured and the temperature rise is directly proportional to the amount of light that is shining in. So, you sense a temperature rise when light is absorbed. This is mainly used for detecting IR radiation or infrared radiation. The other case is your photons. This is the traditional sense in that your photons generate electron hole pairs. Now, we will be mainly dealing with the second type of photo detectors where your photons generate electron hole pairs. So, consider incident light on your material of wavelength lambda. The energy of this radiation of course, you have seen before is nothing but h c over lambda. So, this light can be detected if this lambda corresponds to some sort of transition within your material. So, as long as lambda is less than equal to h c over delta e where delta e is a transition within the material, then your light is said to be detected. So, what are these different transitions that delta e can correspond to? So, delta e which represents the transition in your device or transition in your material, it could be an interband transition. So, it could be from the valence band to the conduction band. That is the simplest and most common form of transition So, for example, if your material is gallium arsenide, then you will absorb light of energy greater than the band gap. So, that an electron gets excited from the valence band to the conduction band. You could also have an interband transition, but instead of going from the valence band to the conduction band, you could have impurity levels within your band gap. So, your transition is from either the valence band or the conduction band to some impurity level. So, typically if you dope a material so that it generates impurity levels in the band gap, then these kind of transitions are possible. If you have junctions, then you have barriers at the junction so that your transition could be across a barrier. So, this could correspond to a barrier height across a junction. For example, later we will look at some short key diode based photo detectors in which case your electrons or your light can have sufficient energy in order to excite the electrons from the metal to the semiconductor in which case they will have to overcome the short key barrier. So, this delta E depends on a variety of transitions and this defines the wavelength range of your photo detector. More specifically delta E determines the long wavelength range that is possible or the minimum or the maximum wavelength that is possible. Another way of saying this is that depending upon the wavelength range you are interested in you will choose the appropriate type of photo detector or the photo detector material range. So, depending on lambda you can choose the appropriate detector. So, the difference between a photo detector here and in the case of a solar cell is that in a solar cell the wavelength range is sort of fixed because it depends upon the solar spectrum that has a specific wavelength range. So, later when we look at the solar cell you will see the solar spectrum and what is the wavelength spread. So, solar cell the wavelength range is fixed. So, we want to choose materials which absorb in that range. The other hand in the case of a photo detector depending upon the wavelength range we will choose what material we want to use. So, the maximum wavelength is determined by delta E. So, any wavelength that is larger than that determined by delta E will not be able to absorb or will not be able to produce your electron hole pairs and will not get absorbed. There is also a lower wavelength regime and that depends upon the absorption coefficient of your material. So, the lower wavelength. So, we have a maximum wavelength which determined by delta E and the lower wavelength is determined by alpha. So, we have looked at the concept of absorption coefficient before. We find that if alpha is the absorption coefficient then the intensity at a distance x within the material was just I naught exponential minus alpha x. So, I naught is the intensity at the surface I of x is the intensity at some depth x and alpha is your absorption coefficient. You have seen earlier that as the wavelength reduces alpha increases which means the material gets absorbed at a lower depth. So, this absorption coefficient determines the lower wavelength regime. If alpha is very large then all of the light gets absorbed in a layer very close to the surface and would not have sufficient electron and hole pairs in order to be able to detect it. So, the higher wavelength regime is determined by the band gap of the transition or the energy of the transition and the lower wavelength regime is determined by alpha. Another important factor in the case of a photo detector is the response time. So, this determines the speed of the device. So, if you think of light arriving in the form of pulses the response time determines how close these pulses are. So, that they can be individually detected. So, if you have light in the form of pulses the response time determines the frequency of these pulses. Remains the speed or the frequency of the pulse. So, the response time depends on the fact that you have electrons and holes that are generated and these must diffuse through the device in order to reach the electrodes and then form your current. So, it depends upon the diffusion coefficient or the mobility of the electrons and holes in the device. If you have a photo detector that is based upon a p-n junction with a wide depletion region then the distance the electrons and holes have to travel is longer which means correspondingly the response time is short. On the other hand if you have a thin depletion region the response time is I am sorry if you have a p-n junction with a wide depletion region then the distance the electrons and holes have to travel is large. So, that the response time is also large. On the other hand if you have a p-n junction with a very short depletion region then the distance the electrons and holes have to travel is small. So, that the response time is fast, but the drawback is the number of electrons and holes generated are small. So, that you need a large amount of signal in order to form or in order to be able to detect the radiation. So, there are different tradeoffs depending upon the design of the device and the response time that is required. The basic metric of a photo detector is called the quantum efficiency. So, the quantum efficiency is defined as the number of carriers that are generated per photon. So, this in turn is related to the photo current divided by the flux of the photons. So, I p h is the photo current this term phi is the photon flux. Another way of writing this is that it is I p h over e and the flux of the photons is depends upon the power of the incident radiation and the energy. So, h mu is the energy of the radiation and p o t is the optical power. In the case of a photo detector they could also be an internal gain mechanism. So, that even though we have a certain number of photons that are incident on your device the number of electron hole pairs are larger. So, we have both a gain and a response time that basically characterizes your photo detector. Now, there are different kinds of these detectors all having different values for gain and response time. So, let me just tabulate some of these types of photo detectors. So, we look at some of the types of photo detectors and then we will look at a comparison of their gain and the response time. Response time is given in seconds. So, a simplest photo detector is just a photo conductor depending upon the applied electric field and we will talk about it in a minute. We have different gain values and the response time is usually of the order of milliseconds. Could also have photo diodes these could be a simple p n junction a p i n stands for a p an intrinsic and an n or it could be a metal semiconductor. So, in all of these cases your gain is typically 1 which means all the light that comes in just gets converted into electron hole pairs. Response time of these devices are typically much better or much shorter. This is around 10 to the minus 11. You could also have charged couple devices this has a wide range of response times. These are all photo diodes you could also have a photo transistor. One of the advantages of a transistor is that it is always possible to have some gain and your response time is of the order of microseconds. Another type of a photo detector is based on an avalanche photo diode. It also has a gain that is larger than unity because it is based on an avalanche process and also very fast response time. So, we have a wide variety of photo detectors. These depend upon the type of materials is used you use and also on the junctions that are formed. We will not look at all of these, but we look at some examples of these photo detectors in order to better understand the mechanism. So, the first thing we look at is a photo conductor. So, consider a simple slab of silicon. We are looking at a photo conductor. So, consider a simple slab of silicon with two electrodes on either ends. So, these can be typically metals. So, they form an ohmic contact with silicon. We want to choose the materials in such a way that you have an ohmic contact. So, this is your central slab with two ohmic contacts. So, let L be the length of your slab. So, we can have incident light fall on to your slab. So, you have incident light of some energy which depends upon the wavelength. So, it is H mu or H c over lambda and if this energy is sufficient it will generate electron hole pairs. If we now apply an electric field across the silicon by using your ohmic contacts, we can basically extract the electrons in holes and then form a current which is your photo current. So, one of the terminals is connected to a positive side, the other is connected to a negative. In this case there is an electric field. So, the electrons in holes move in the opposite direction. So, the current in this device is directly proportional to the number of electron hole pairs that are generated which in turn depends upon the intensity of the light that falls on the material. In this case of a device the gain is given by tau divided by the time for your holes or for the electrons and one over time for the holes. So, tau refers to the life time of the carriers because once your electrons in holes are generated they will like to recombine. So, the recombination is determined by the carrier life time t r n and t r p they are the transit time for these carriers to the electrodes. This in turn depends upon the length of the device. So, t r n is depending upon the length, it depends upon the mobility of your electrons or holes. So, mu n and the applied electric field. Similarly, t r p is just l over mu h times the electric field. So, higher the mobilities or higher the electric field shorter is the transit time and similarly smaller the device. So, smaller l shorter will be your transit times. Usually in the case of a simple photo conductor they will always be some thermal noise because you will always have some thermally generated electrons in holes. So, these devices are usually operated at low temperatures. So, typically they are operated at liquid nitrogen temperatures in order to minimize the thermal noise. So, to reduce. So, the next device we are going to look is a photo diode. So, here you are going to put two different materials over p and n in order to form a junction. So, in the case of a simple photo conductor all we had was a slab of a semiconductor material. So, it could be silicon it could be gallium arsenide and then that just generated electron hole pairs. In the case of a photo diode we use a p and n material. So, that you form a junction. So, this can be a simple p n junction or a modification of that which is your p n junction. So, electron hole pairs are generated either in the depletion region of the p n junction or they generated in the intrinsic region. These electron and hole pairs are then separated by applying a reverse bias to the junction. So, that the electrons go towards the n side holes go towards the p side and then you have a current. So, consider a simple p i n kind of device. So, the intrinsic region is typically wide and the p and n regions are short. These devices are usually operated under reverse bias. So, that a negative charge is applied to the p side. This particular example the n side is just grounded. We have some incident light shining on this p i n device that is just your optical radiation. So, we want to make the p and the n regions short. So, that the light can shine through and then most of the electron hole pairs are generated in the intrinsic region. So, p and n are typically thin. So, if you were to draw the energy band diagram for this under reverse bias have my p have intrinsic I have n. This refers to your conduction band. This refers to the valence band. This is E f p. This is E f n. So, in this particular case there is a reverse bias. The reverse bias voltage depends upon the difference in the Fermi levels. So, now we have incident light that falls on your material. So, that generates electrons in the conduction band and holes in the valence band. Because of a reverse bias these electrons and holes are separated and they contribute to the current. In the absence of any light there will be a small current which is your reverse saturation current. It is similar to any p and junction under reverse bias. When we shine light this current is enhanced because we now have an additional photo current due to the electrons and holes that are generated. So, in the case of these devices p and n are really short. So, that most of the absorption takes place within the intrinsic region. If alpha is the absorption coefficient and w d is the width of the intrinsic region. Ideally we want alpha times w d to be much greater than 1. So, this is for high quantum efficiency. Another way of saying that is that 1 over alpha is your penetration depth. So, that we want the width of the region to be much larger than the penetration depth of the wavelength of interest. So, these cases whether you have a simple p n junction or a p i n you could have them of the same material. Another way to do that is to have a hetero structure based device. So, that you can have a hetero junction photo diode. So, let me draw a simple schematic of such a structure presents the contact. It is my p region that is the intrinsic region then I have the n region. So, my n region is made of indium phosphide and my p and the intrinsic regions are made of indium gallium arsenide. So, indium phosphide has a higher band gap 1.27 e v and indium gallium arsenide has a band gap of 0.73 e v. The advantage of the hetero junction device is that in the case of a regular p i n the p and the n region should be really short in order to not to absorb the light. But here since indium phosphide has a higher band gap wavelength whose energy is less than this will have a very little absorption in the indium phosphide. So, that the thickness of the n layer does not have to depend upon the wavelength of the light. You can have a thicker n layer than what you normally have in a regular p i n device. So, in this case light shines from below. So, that you can have a thicker n layer. So, that all the wavelength whose energy is below 1.27 will get absorbed. Another advantage of the hetero junction photodiode is that you can cut off certain portions of the wavelength that you would not want. For example, if you do not want to look at wavelength above 1.27 by having a thick n region those wavelengths or those energies can be absorbed. So, that only wavelength of a certain range can be detected by the photo detector. So, the hetero junction photodiode it works on the same principle as a regular p n or a p i n, but offers added functionality because of the difference in the band gaps. The one caveat is we have to grow different materials. So, growing these materials with a good epitaxial contact is very important. We can also have a photodiode based on metal semiconductor junctions. We have seen earlier that there are essentially 2 kinds of metal semiconductor junctions. One is your short key junction, the other is the omic junction. So, in the case of a photodiode we want a depletion region. So, that we can generate electron hole pairs. Now, the short key junction is the one that has a depletion region. So, we use a short key junction to form your photo diode. So, there are 2 modes of operation of a metal semiconductor diode and the reason we have 2 modes is because we now have a barrier between the metal and the semiconductor. This is your short key barrier. So, in the first case if the energy of the photon is more than the band gap E g, then it behaves like your regular photodiode. Electron hole pairs are created. These are created in your semiconductor and they contribute to its current. So, you have electron hole pairs in the semiconductor that lead to current. On the other hand, if you have light of energy less than the band gap, but more than the barrier height. In this case it is your short key barrier. So, the energy is more than the barrier height. So, you can excite an electron from the metal and take it above the short key barrier. In this case it is called internal photo emission and this electron can contribute to the current. So, you can have a photo excited electron from the metal crossing over the short key barrier into the semiconductor. This process is called an internal photo emission. So, consider the example of a short key junction in equilibrium. So, this is my metal side E f. You have seen earlier that a short key junction is formed when the work function of the metal is greater than the work function of the semiconductor. I have a depletion region. So, my semiconductor is n type that is my Fermi energy. I have my conduction band E c and then I have my valence band. So, that you have a depletion region on the semiconductor side. There is a built in potential which is E v naught and there is a short key barrier height phi b. The short key barrier height depends upon the difference between the work function of the metal and the electron affinity of the semiconductor. So, when we apply a reverse bias to this junction your semiconductor potential shifts. The metal is still the same semiconductor shifts you see E v E f E f n for reverse bias. So, if you have light of energy greater than the band gap. So, h mu is greater than E g.  The other hand if you have light energy greater than the short key barrier but less than the band gap. Then you can take an electron from the Fermi level of the metal and then take it above the short key barrier and that can also give you current. So, by using a metal short key junction you can increase the wavelength range that you want to interrogate with your photo detector. You are no longer limited by the band gap of the material, but you can extend it further depending upon the short key barrier. So, if you were to draw the quantum efficiency of this device versus the energy. So, eta is your quantum efficiency Q E versus energy E of the light. So, that is just h mu. You have one term that corresponds to E g. Then there is phi b which is the barrier. So, anything below the barrier will not get absorbed. Above the barrier you have some gain because of the internal photo emission process and above E g your gain is higher because you now have the transition within the semiconductor. So, this is conductor valence band to conduction band. Usually instead of using metals you can also use silicites. For example, if you have platinum you could have platinum silicite forming a junction with silicon that can be used as a photo detector. So, in the case of a metal semiconductor photo detector the caveat is the metal layer should be really thin because metals usually have very high absorption coefficients. So, the metal layer should be thin because alpha is very large. For example, if you have platinum silicite and silicon. So, platinum has a work function of 4.97 E v. Silicon has an electron affinity of 4.05. So, the short key barrier phi b is just the difference between these two. So, it is 0.92 E v. The band gap of silicon E g is 1.12 electron volts. This corresponds to a wavelength of approximately 1100 nanometers. So, as long as your wavelength is below 1100 or energy is above E g then the light will be absorbed by the silicon. But if your energy is between 1.12 and the short key barrier in the light will be absorbed by the platinum silicite layer in the internal photo emission process. So, we have looked at 3 examples of photo diodes. So, you have a simple p-n junction or a p-i-n or a metal semiconductor. You could also have a photo transistor. In this case you have a regular bipolar junction transistor which we have seen before it has an emitter base and a collector. So, in this particular case you modify your simple bipolar junction transistor to have a larger base. So, that electron hole pairs are generated within that and this in turn gets separated and forms your current. You could also have a hetero junction base device from your transistor in order to improve the gain. So, we have looked at different examples of photo detectors. In all of these cases the wavelength range that can be scanned depends upon the type of material that you have. In the next class we are going to look at a solar cell which works in a similar way to a photo detector. But the wavelength range is fixed it depends upon the solar spectrum that is incoming onto the sample. So, we will look at the working of a solar cell and also some of the different materials and efficiencies when we use them in the solar cell.


Good afternoon. I'd like to call the meeting of the Board of Public Utilities for the City of Santa Rosa to order. May we have a roll call, please? Yes, Chair Galvin. Here. Vice Chair Arnone. Here. Board Member Badanford. Here. Board Member Gravel. Here. Board Member Walsh. Here. Board Member Watts. Board Member Wright. Jerry. Here. Thank you. Good afternoon, everyone. A reminder to please mute your phones and microphones when they're not being used and to put away your cell phones and personal computers. Item number two is statements of abstention by any board members. Do we have any? Mary Nunn. We have no study session. The minutes from the October 7th meeting are we're sent to us. So at this point I will open it up for public comments and the approval of the minutes. If you wish to make a comment via zoom, please raise your hand. If you're dialing in via telephone, please dial star 9 to raise your hand. Do we have anyone? We have no public comments. And we have no one in the city council chambers. So we're okay there. So the minutes will be approved and entered. We'll now move to the staff briefings. Item 5.1, Director Burke. Thank you, Chair Galvin and members of the board. Our first staff briefing is our virtual water reuse tour and Elise Howard, our communications coordinator, will be making the presentation. All right. Good afternoon, Chair Galvin and members of the board. It's my pleasure to be here today to debut Santa Rosa waters virtual water reuse tour video. Next slide, please. Santa Rosa water has a long history of water reuse. In fact, a few years ago we celebrated the 50th anniversary of the Laguna treatment plan since coming online in 1968. The plant has become a hub of the city's water reuse program reducing billions of gallons of recycled water and thousands of tons of biosolids each year that are beneficially reused and each year pre COVID the plant welcomed visitors from around the world, students and interested individuals of all ages but due to the pandemic we currently have our in-person tour on hold but plan to restart soon with all staff scheduled to return to campus on the 1st of November. In the meantime, the team has been working on a virtual tour video to provide an online learning opportunity and to enhance the in-person tour experience once we resume. Next slide, please. As you can imagine, creating a 10-minute video requires a bit of planning and coordination to impactfully tell our story. This required building and editing scripts in numerous days of filming at various locations with a variety of staff. We used high-quality video and drone footage to capture the magnitude of service that we provide to show the people that work around the clock to operate the system and to showcase the value of water and the importance of water reuse. A lot of hands touched this project and I want to thank all of the water reuse and Spanish speaking staff that participated in making these videos. I also want to thank our consultants, data instincts, and Ron Thing Media for making our vision a reality. Next slide, please. We are approaching the finish line with this project and I anticipate launching this new outreach tool to the community in November. This video has been produced in both English and in Spanish and we are currently finalizing the Spanish version. Once both of these videos are completed, we will share these with the community using the city's webpage and promote it through the city connections e-newsletter which reaches over 100,000 subscribers, our YouTube channel, and the city's social media accounts. Next slide, please. All right, here we are at the main event. I believe you all have been waiting for it. I'm going to ask Easter to tee this up for me and I'd like to show you just a couple minutes of this 10-minute video and following the meeting, I'd be happy to send you a link of the full version. So, Easter, whenever you're ready, you can press play. So how do we do what we do? Let's have our environmental specialist, Denise, guide us through the process of how we clean that wastewater. All sewage coming into the treatment plant goes through four steps of treatment, primary treatment, a biological treatment, filtration, and disinfection. This clean recycled water is used for parks, grapes, crops, and more. The plant produces a remarkable 7 billion gallons of recycled water per year and most years, nearly all that water is beneficially reused, offsetting the demand for valuable drinking water. The majority of our recycled water is pumped 41 miles to a geothermal energy production facility called the Geysers, high in the Mayakamis Mountains. There, it's pumped underground to recharge steam fields, which are used to generate electricity for nearly 100,000 homes in the North Bay. By recharging and replenishing the underground steam fields, our recycled water helps to support the generation of clean renewable electricity. Approximately one-third of our recycled water is used for agricultural or urban irrigation. In years that the plant produces more water than can be reused, the extra recycled water is released to the Laguna de Santa Rosa and returned to the Russian River. The solid component of sewage is processed and turned into nutrient-rich biosolids. Each year, over 30,000 tons are used as fertilizer and soil amendment for the city of Santa Rosa's farms and other agricultural lands. Right, so I hope you enjoyed that sneak peek and maybe you learned something and now you're very interested in watching the full video. So, at this time, I'm happy to take any questions from the board. Thank you very much. Board member questions or comments? Very nice work so far. I look forward to seeing it get released both in English and in Spanish. And at this point, I guess then we will open it up for public comments on item 5.1. If you wish to make a comment via Zoom, please raise your hand. If you're dialing in via telephone, please dial star 9 to raise your hand. And there's still no one here in the council chambers. Do we have anyone, Secretary Atha? We have no public comments. That will take care of item 5.1. We'll move now to item 5.2. Director Burke. Thank you, Chair Galvin and members of the board. Item 5.2 is a staff briefing on our LEET and Carly Preeter Springs Groundwater Wells and our interim deputy director for Capital Projects Engineering, Andy Allen, we'll be making the presentation. Good afternoon, Chairman Galvin, members of the board. Yes, my name is Andy Allen, Interim Deputy Director of Transportation Capital Projects Engineering. I'm excited to be able to talk about a couple of projects that we were working on for our, as part of the groundwater program. Next slide please. This is, we're going to talk about two well rehab replacement projects. One is for our LEET well and the other is for the pair of wells, which is Carly and Peter Springs, and they're located right next to us, next to each other on adjoining lots. Next slide please. First, we'll talk about the LEET well rehabilitation. That's the site of the LEET well. It's on a long driveway off Elite Avenue, parallel with Aaron Drive. Next slide please. The LEET well was originally installed in 1953, 10-inch diameter, 323 feet deep, and has a rated capacity of 240 gallons per minute. The biggest issue that we have on this is a separation in the casing, and it's not currently in use. We stopped using that when we discovered the separation in the casing. Next slide please. So we have, the current task is to actually assess the well itself. We're going to have to spot clean the well screen and do a video survey, aquifer testing, water quality sampling of course, dynamic steady state profiling, and also condition assessment of the well house. So we need to determine if we can rehab that existing well, or if we're going to have to decide to drill a new well adjacent to that, and then is that existing well house satisfactory for our needs in the future? So that's the current task, and then the future task of course will be to design the project based on that current study. We have funding started on this project, originally in fiscal year 1920, and also this last current year one, 21-22, and we have programmed in about half a million dollars a year for the next several years into the CIP. We may need to accelerate that the funding going to this project, depending upon how quickly we move through and with an estimated current need of three million dollars. Hopefully we'll be completing this work in fiscal year 23-24. Next slide please. Here are the pair of wells, Carly and Peter Springs. Peter Springs is located on Peter Springs Park, and Carly is on a single piece of property adjacent to that, and the pumping infrastructure is on the Carly property. Next slide please. So we'll start with the Carly well, originally installed in 1954, 8-inch diameter, 208 feet deep, rated capacity of 700 gallons per minute, which is a pretty good number. What we have as issues are the age of the well itself, the presence of a liner, and we do have some ground displacement issues at the site, which need to be evaluated completely. And then the current use for this well, we actually use it for irrigation. Next slide please. Again, adjacent property, Peter Springs well, which originally installed in 1923, 10-inch diameter, 160 feet deep. It has a rated capacity of 500 gallons per minute, but an operational capacity currently of 150 to 200 gallons per minute. The issues here are an open borehole below a shallow casing, and the top of the casing is actually in a vault below ground, which is something that will need to be corrected. And it too is currently used for irrigation. Next slide. Also, I'm talking about Carly Peter Springs. There was a previous evaluation on LEET that evaluation is going on currently for Carly Peter Springs. We did this evaluation a few years ago. That evaluation came up with the recommendation to replace the Carly well. That has a lot to do with the ground displacement and being able to rehab the building and actually replace the building. So the plan is to drill a new well and to put a whole new pump house and pumping system on the Carly site. And that pumping system will continue to support Peter Springs. And we're going to rehab the Peter Springs well, bring it into conformance of current standards, bring the casing through the entire well, and bring the top of the well up above ground, which is how it should be done. And again, we'll replace the pump house and all the occurrences necessary for this project. Next slide, please. So current task, because we've already done an evaluation, is pre-design and design, which will include a geotechnical investigation, a site design, which will be a well and building layout, and then preparation of well construction and destruction design, including plans and specifications. We had funding started on this project in 2019-20 and added some in 2021. And right at the moment, we have about $2.5 million in that fund. And so we will be coming back for future funding as we evaluate the rest of the project. Current estimate about $3.2 million. And hopefully we'll be about the same completion date on this project, 23-24. Next slide. Brings me to the end of the presentation. I'm happy to answer any questions. Thank you, Mr. Allen. I'll open it up for any board member questions or comments. I had just one question on the Carly and Peter Springs. You said irrigation. Is it just irrigating that nearby park and possibly the junior high, or is it going somewhere else? That's the primary use of the water. We also use that water to top off Lake Ralfine. I believe there's a pump. We pump it up to that lake when it starts to evaporate during the summer. Thank you. Any other board member questions or comments? All right. I will open it up then for public comments on item 5.2. If you wish to make a comment via Zoom, please raise your hand. If you're dialing in via telephone, please dial star nine to raise your hand. Secretary Etha. We have no public comments. And there's no one here in the chambers. So that will take care of item 5.2. We'll now move to item 5.3. Thank you, Mr. Allen. Most welcome. Director Burke. Thank you, Chair Galvin and members of the board. Our last staff briefing is our water supply update. And our Deputy Director of Water Resources, Peter Martin, will be making the presentation. Sorry, I have trouble getting off mute there. Good afternoon, Chair Galvin and members of the board. Very pleased to give you this water supply update on a rainy October afternoon. Just to give you a sort of a few quick points about the rainfall we're experiencing, it's very likely that we'll have received two to three inches by a Sunday rainfall. As of last night, we received about 1.4 inches since beginning of October. So that would put us sort of above the average that we'd see in the month of October already. So usually that's less than an inch. So definitely a welcome change. And then multiple weather models are suggesting that the region could receive six to eight inches of rain in total through this series of storms that could carry into the next two weeks. So we've been told that we need a minimum of seven to 10 inches of rain to begin the runoff process where the soil in the region is damp enough to produce runoff into our regional reservoirs. And further, the region needs at least 25 inches or more of rainfall this winter to be able to remove ourselves from potential water supply shortages next year. So hopefully a lot more to come. I guess we can go ahead and start the presentation next slide. So in terms of Lake Minnesino storage, Simo Water has had some issues with their reservoir data collection at Lake Minnesino. But as of Monday, they were able to take some manual reads and based on those manual measurements on Monday, the reservoir is about 13,400 acre feet or about 22 percent of their target storage for this time of year. Reservoir outflow has been consistently around 52 to 55 CFS. That's down from last month of the 65 to 70 CFS or cubic feet per second, which was, as you remember, being driven by channel losses and channel losses in the upper Russian River, which are now lessening. Next slide. So as of today in Lake Sonoma, reservoir storage is about 105,584 acre feet and releases have remained steady at 85 cubic feet per second. So with the early returns on rainfall, we did hear from Simo Water that they are now rejecting that the reservoir will not fall below that 100,000 acre foot threshold until at least mid-January, hopefully not at all. But this is a sort of a departure from the last update and the projection of that milestone by the end of November, which is some positive news. So go into the next slide, please. So as a reminder, Simo Water is under a temporary change order issued by the state and that order includes their requirement to reduce their diversions by 20 percent over 2020 levels. Through this timeframe, they have exceeded that target, so they are well in compliance with that requirement of their order. Simo Water is still, I should step back, just to note that order does carry through December 10th, so Simo Water is still anticipating filing another temporary change petition by the end of this month to allow them to continue to reduce their releases from both reservoirs and preserved storage over winter. It's likely that they're going to ask to seek some relief from the existing 20 percent reduction that is in the current order as natural stream flows start to return and the Russian River and contractors' customers stop outdoor irrigation and are limited in terms of what they can cut back over the winter. But nonetheless, it is still incredibly important that our region continues to conserve water for the foreseeable future because we have a long way to go before the next spring and we don't know what the winter will continue to produce in terms of rainfall for the region. So we'll be working together in the region to reinforce that message over the next coming months despite, as you can tell, that it's raining. So next slide. So through this graphic, you can see we didn't achieve our water savings target at 20 percent in the month of September compared to last year. We also sort of fell short, unfortunately, achieving our water allocations for Simo Water for that month as well. However, the good news, as you can tell, is that we still remain in line with our cumulative allocations from Simo Water for the months of July through September. And we're hopeful that the additional wet weather that we're experiencing and significant outreach efforts surrounding folks turning off the irrigation over the last month will be able to achieve the savings in the month of October through the month of December. We have still a long way to go to get through December in meeting our individual targets. Next slide. So, you know, just looking ahead to fall and winter campaign, you know, over the summer, we were definitely hitting very hard on getting folks to be very judicious with their water use outdoors and will continue to move forward with a different message over the fall and winter. You know, obviously, we've begun over the last month asking folks to turn off the irrigation. It's all that more important now that rain is falling. And then, of course, within the fall and winter months, when the irrigation season has ended, the only way to achieve water savings since indoors. So, you know, while we're still continuing to help folks prioritize protecting trees and shrubs during the drought, we are asking the turn off the irrigation and then we'll be finding other ways to help people with irrigation going forward, including promoting rainwater capture and greywater systems this month. And then, as we move into winter, we'll be focusing on helping folks save water and doors and fixing leaks. Next slide. We still have some community events planned. I do want to kind of just first start off with, you know, just going over our recent drop by event is the last planned drop by event of the year. We did deliver 600, 1,600 drought kits here in Santa Rosa at our locations at Youth Community Park and Colbin Creek Park. So that was a successful event. And then looking forward, we'll be participating and trying to continue to hand out as many kits as possible and other educational opportunities, including Halloween at Howard Park and in the Halloween event and the Rosalind, hosted by the Rosalind Community Building Initiative on October 29th. And then we'll be looking to see folks out at the Santa Rosa Farmers Markets as well through the remainder of the year. Next slide. I do want to highlight that we continue to, between the Save and Water Partnership and Santa Rosa, with our partnership with Daily Acts, continue to host several workshops over the next few months that may be adventurous to the public. These are well attended so far. So we're seeing this virtual format is working. There was a Greywater Basics presentation and there's a link to that video from the Greywater Basics Workshop on October 14th. That will follow up with the Laundry and Landscapes Workshop and then, you know, we're moving into some other workshops as well. Folks can go to srcity.org slash workshops to register for those. I do want to point out that the Rain Barrel Systems Workshop will be giving away a free rain barrel to folks that attend, well at least one, as a giveaway in hopes that we can get more people to attend that as well. So next slide. So that kind of concludes my brief presentation today. I'm happy to answer any questions from the board at this point. Thank you Deputy Director Martin. Questions from the board for the Deputy Director Vice Chair Arnone. Thank you. I was pleased and glad to hear that Lake Sonoma is projected now to stay above 100,000 acre feet until mid-January. Could you remind us of the consequences of what happens if Lake Sonoma falls below 100,000 acre feet? Yeah, so we've heard in several conversations from Sonoma Water Vice Chair Arnone about their plans looking ahead. There are terms in their water rights and of course Decision 1610 by the State Water Board that says that once they reservoir falls below 100,000 acre feet before June, I think it's June 15th or maybe July 15th, they're required to reduce diversions to by 30%. However, there is a secondary sort of threshold of 70,000 acre feet that they're held to in that as well. So when Sonoma Water is going forward with their proposal to the State Board on a new change order or request in the terms of a temporary sea change petition, they will be providing to the State A plan to ensure that they don't fall below that 70,000 acre foot threshold over the next year. So there's some flexibility in the way that's worded. There are alternatives that can be proposed to that additional cutback in their diversions. Okay, thank you. Other board member questions or comments? All right. If not, we will take public comments on item 5.3. If you wish to make a comment via Zoom, please raise your hand. If you are dialing in via telephone, please dial star 9 to raise your hand. Secretary Aitha? We have no public comments. And no one here in the chambers. That'll take care of item 5.3. We have one item on the consent calendar, item 6.1. There are no questions about the item. We can have a motion, please. I'll move. We adopt the consent calendar. Second. Thank you. We have a motion by board member Wright and a second by board member Badanfort. At this time, we'll take public comments on item 6.1. If you wish to make a comment via Zoom, please raise your hand. If you're dialing in via telephone, please dial star 9 to raise your hand. Secretary Aitha? We have no public comments. No public comments and no members of the public in the chambers. We'll now have a roll call vote, please. Chair Galvin? I. Vice Chair Arnone? I. Board member Badanfort? I. Board member Grable? I. Board member Walsh? I. Board member Wright? I. Thank you. We'll now move to report items. Item 7.1. Director Burke? Thank you, Chair Galvin and members of the board. Item 7.1 is a request for a change of scope, change order for our pump station, for our emergency well located at a place to play. And Eric Robber, our supervising engineer with our capital projects team, will be making the presentation. I'm having a little difficulty promoting Mr. Robert to panelists. Hold on just a moment, please. Mr. Robert, I can't promote you to a panelist for some reason, but I have given you permission to speak if you can unmute. Can you hear me now? Yes, thank you. Great. Thank you, Chairman Galvin, fellow board members. Good afternoon. My name's Eric Robber, supervising engineer with the Transportation and Public Works Department. I'm pleased to be here today to present our request for a scope of work change order and additional contingency in connection with the emergency pump station at a place to play park in Santa Rosa. Next slide, please. In today's presentation, I'll briefly describe the project and its purpose, some project background information that brings us to where we are today and close with our analysis of the issues and a recommended path forward. Next slide, please. Project is located in the north side of West Third Street, just east of Fulton Road, at the intersection of Third Street and the most westerly entrance to a place to play park. The purpose of the project is to convert an existing test well into an emergency well and connect it to the city's water distribution system so that it's available in the event of an emergency. Next slide, please. Work associated with the project consists of site grading, constructing a pump station facility, rehabilitating the existing well, connecting the system to sewer and storm drain facilities, bringing existing power and telephone to the project site, constructing a perimeter fence with aesthetic enhancements and restoring disturbed areas. Next slide, please. In 2006, a test well was installed at the corner of Third Street and the westerly most entrance to a place to play park. In 2016, the test well was inspected, reconditioned, and a pumping test performed. Pumping test results indicated a sustainable yield on the order of 500 gallons per minute with no primary water quality thresholds being exceeded. Between 2017 and 2020, we prepared a design to convert the test well to an emergency groundwater well and install the previously described infrastructure. In May 2020, the city awarded a contract to Team Jalati, Inc., and work on the project began shortly thereafter. However, in November 2020, the city suspended the construction contract due to the discovery of arsenic in groundwater from the test wells at levels exceeding drinking water standards. Since then, feasibility studies were performed to evaluate alternatives to addressing these elevated arsenic levels. On the basis of these feasibility studies and subsequent bench-scale testing, the design was revised to reduce arsenic levels in groundwater below drinking water standards. Next slide, please. The design was revised to include measures to increase iron in groundwater to facilitate formation of iron arsenate solids and remove those solids via cartridge filters. To accomplish this, the building size was increased. A chemical feed system added, instrumentation and controls revised, and a large diameter pipe loop to facilitate arsenic arsenate formation was added. The estimated cost to implement these revisions is $870,369. Next slide, please. It's thus recommended by the water and transportation and public works departments that the Board of Public Utilities by Motion approve a change of scope contract change order to include constructing an arsenic removal treatment process for construction contract number C01965 with Team Gelati, Inc. of Pettiluma, California. Increase the original bid amount plus contingency by $957,405.90, which includes a 10% contingency and authorize a total contract amount of $3,035,618.94. Next slide, please. That concludes my presentation, and I'm happy to answer any questions. Thank you, Mr. Robert. Any Board member questions or comments? Board member Wright? Just once again, I support this item. Just curious, what was the status of the project when work was halted? Most of the grading had been completed. Power was brought to the facility from a remote location. Some of the plumbing work was done tie-ins to the system, and that was about it. No building construction had occurred, so in some ways the timing was fortuitous in that we don't have to undo anything that this revised design would have required. Thank you. Any other board member questions or comments? All right, we'll open up item 7.1 for public comments. If you wish to make a comment via Zoom, please raise your hand. If you're dialing in via telephone, please dial star 9 to raise your hand. Secretary Aitha? We have no public comments. And no one in the chambers. May we have a roll call vote, please? I'll offer the motion. I'm sorry. I guess we do need a motion. I'd like to make a motion that we, by motion, approve a change of scope contract change order to include an arsenic removal treatment process for construction contract number CO1965 of Team Jalati, Inc., at Luma, California, by $170,369 and authorize a total contract amount, including a 10% contingency of $3,035,618.94. We have a motion. I second that motion. Seconded by Board Member Walsh. Just to be on the safe side, I'll open it up again for public comments on item 7.1. Secretary Aitha? We have no public comments. All right, now we can have a roll call vote, please. Chair Galvin? Aye. Vice Chair Arononi? Aye. Board Member Badenford? Aye. Board Member Grable? Aye. Board Member Walsh? Aye. Board Member Wright? Aye. Thank you, everyone. Item number 8 is public comments on non-agenda items. We'll now take any public comments on item 8. If you wish to make a comment via Zoom, please raise your hand. If you're dialing in via telephone, please dial star 9 to raise your hand. Secretary Aitha? We have no public comments. And no one in the chambers. That'll take care of item 8. We have no referrals. We have no written communications. Do we have any subcommittee reports? I don't think we've had any subcommittee meetings. Any Board Member reports? Okay, we'll move to the director's report. Item 13. Thank you, Chair Galvin and members of the board. I did have a couple items to update the board on. First, I wanted to provide an update on our testing for purr and polyfloral alcohol substances or PFOS. On July 9th of last year, the state water board issued an order requiring all publicly owned treatment works to investigate wastewater and biosolids for the presence of PFOS, otherwise known as forever chemicals, and to submit a final report. The water department started developing our sampling methods, which are very prescriptive because many personal care products and clothing contain PFOS chemicals, and the analysis to detect these chemicals is calibrated down to parts per trillion. So these samples can only be analyzed on very specific instruments in clean rooms free of contaminants. The Laguna Environmental Lab coordinated with an outside lab to analyze these samples. Happy to report that the sampling was done well by the team, so all of our blanks came back blank, which is a great thing. The city has completed the sampling, written the final report, and submitted the results and the report to the State Water Resources Control Board, actually just earlier this week. And those results will be combined with results gathered from other sampling done by other treatment plants across the state to determine the presence of PFOS in wastewater and biosolids. We do anticipate that this will result in some type of regulatory rulemaking at some point in the future. At this point, the data is still too early to determine really to make much analysis of what we found, but we did find PFOS present in influent effluent and biosolid samples. The next item I wanted to let the board know that engineering staff from both the water department in the transportation and public works department, as well as Caltrans and local consulting firms attended a workshop just yesterday, I think, sponsored by the Engineering Contractors Association. And the goal of the workshop was to identify if there's a problem with backlog projects for roads and utility projects in the city of Santa Rosa and also to explore and collaborate on how to improve getting projects out on the streets. We did receive valuable feedback during that meeting and staff will be following up with the Engineering Contractors Association on specific topics in the future to continue gathering feedback in ways that we can improve putting projects out. And last, I wanted to let the board know that today is Imagine a Day Without Water. And we are taking part in Imagine a Day Without Water. It's a national day of action meant to raise awareness about the value of water and the infrastructure that provides this valuable resource. As a participant, we are asking the community to take action by learning more about the water systems that deliver water to our homes and businesses each day and the importance of investing in our water future. And community members as well as our customers are encouraged to visit srcity.org slash value of water to learn more about this and imagine what it would be like to have a day without water. And that is my report and I'm happy to answer any questions that the board may have. Thank you, Director Burke. Any board member questions or comments? Very good. Then we will open it up for public comments on item 13. If you wish to make a comment via Zoom, please raise your hand. If you're dialing in via telephone, please dial star 9 to raise your hand. Secretary Aitha. We have no public comments. And no one here in the council chambers. That concludes our agenda. So I'll adjourn the meeting. Wish you all a happy Halloween. Enjoy a trick or treating. Hopefully you get wet and hopefully we have a nice wet two weeks until we meet again. So we are adjourned. Thanks.


Wow Look at it. It's all in the bottom of the creek bed Now look at it, but they burned all the chemicals off of there, right? That's what I heard. Yeah Residents in East Palestine Ohio were told that the water in their town was safe after a train derailment poisoned them Now they're not buying it and I think for good reason the video that we just watched demonstrates that it very clearly is is Not normal at a minimum, right? But the governor is trying to do everything in his power to convince them That it is safe and everything is copacetic when in actuality when he made this declaration He didn't have the full picture and we'll get to that But first as Chris D'Angelo of HuffPost explains the testing that Ohio authorities relied on to declare the municipal water in East Palestine safe to drink after a disastrous train derailment was funded by the railroad operator itself and did not initially comply with federal standards HuffPost has learned Although the drinking water in East Palestine may indeed be safe as officials have repeatedly stressed in recent days Independent experts argue the initial batch of samples that a consulting firm hired by the rail company collected and submitted to the lab Should not have been used to make such a determination The lab report on the railroad funded sampling indicates the samples were not handled in accordance with federal environmental protection agency standards Sam Bickley an aquatic ecologist at Virginia scientist community interface an Advocacy-focused coalition of scientists and engineers alerted HuffPost to the sampling errors and called the report extremely concerning There results that claim there were no contaminants is not a reliable finding He said via email I find this extremely concerning because these results would not be used in most scientific applications Because the samples were not preserved properly and this is the same data They are now relying on to say that the drinking water is not contaminated David Erickson a hydro geologist and the founder of water environmental technologies an environmental consulting firm in Montana called the sampling sloppy and amateur now experts are saying that the reason Why these results aren't trustworthy is because in one of the samples there was an air bubble now The reason why that's bad is because additional contaminants can get trapped within that air bubble And if they are well, then they will go undetected which means that that is a massive sampling error But Norfolk Southern is saying well, it's just a recording error. No It's not just a recording error. That is a sampling error that throws the results into question now Citizens in East Palestine aren't buying it and I think rightfully so in this close to the the train derailment I don't trust it. I am frustrated here. I am.  There is no way we are safe being here Deb Blair a cashier at the sparkle market in east Palestine says bottled water has been flying off the shelves Water is the big thing here right now. Everybody is wanting water. They don't want to drink the water They don't want to give it to their animals, you know, this is worse than what everybody thought it was And the people in town are afraid and they're scared for good reason Now republican governor Mike DeWine rushed to declare the state's water safe Before they even had the states results back in so he was satisfied with The samples from norfolk southern and immediately as quick as he could Said yep, everything is fine now When that was wrong because when the state's results came in It confirmed the suspicion of residents as common dreams explains The biden administration said in a press call friday that norfolk southern has not been solely behind the testing That's been conducted so far with the spokesperson telling reporters It's been with the colombiana county health department collecting samples along with norfolk southern and sending those as split samples to two different labs for verification The state EPA however did not receive the health department's results until after de wine declared the water safe Based on a comms flawed testing The lab report shows low levels of the chemical dibutal phthalate Which is not linked to cancer in humans, but can cause headaches nausea dizziness irritation of the eyes and throat and seizures Some of the residents who were told days after the derailment that they could safely return to east palestine have reported symptoms Including headaches nausea dizziness and shortness of breath. So do you understand the issue here? Residents are being told that the water is safe but The water contains contaminants at least in the short term That's making them sick as former state representative rob whip were put it the loss of credibility by public health agencies has and will continue to have disastrous real-world consequences And he is exactly correct about that. Remember how corporations pressured the cdc to loosen testing requirements In order to ease the labor shortage during the second year of the pandemic. Well, they did that they complied with big business Americans remember these things They remember how time after time the government sides with corporations and their profit motives over the people And it's sickening. This is just another example of that now transportation secretary peep buddha judge Is pretending to be powerless, but don't you worry because as abc news reports He wrote a strongly worded letter to norfolk southern And i'm sure that they are shaking in their boots after reading that now to be fair The lever reports that the department of transportation is expanding rules that seemingly require more transparency From these types of companies, but transparency alone is insufficient These companies need to know that it will cost them greatly If they cut costs at the expense of the communities that they're supposed to be serving They need to fear nationalization They need to fear so many fines That they will be put out of business if they do not do what is necessary to maintain safe standards but They know that the worst that they have to fear oftentimes is a little slap on the risk and a pure disaster that can be cleaned up with time Americans will forget with time They know that the government doesn't represent the people and the government is squarely in the camp of these large multinational corporations Just last year congress voted to break a strike at the behest of these railroad companies who refused to give their workers a single Day of paid sick time So we all know Who the government represents it's not Us it's it's these large Multi-billion dollar companies who put profits over people and that is sickening and this is just another example that proves that This is the way that it is