Chemical Metering Pumps: Choosing Appropriate Ones

Posted on: 9 February 2018


As a municipal employee at the local wastewater treatment plant, you might have to inspect and reorder chemical metering pumps. These pumps control the flow of the various chemicals used to treat the water that comes into the facility. If you've just encountered a broken pump that must be replaced, you'll also need to think critically about the new one you'll order. While searching, consider these pump necessities.


Many older pumps release the same amount of chemicals no matter what. However, that can lead to over-treatment which must be corrected later and a waste of money, as your pumps might be releasing more than is necessary. Seek out self-regulating pumps that have the ability to adjust chemical release according to the volume of liquid in the system at any given time.

Corrosion-Resistant Materials

Of course, some of the chemical solutions used in the facility are acidic and corrosive. Pumps can fail early if they're not suitably matched to the chemicals they encounter each day. For that reason, you need to search for corrosion-resistant pumps. These can be somewhat costly depending on the degree of corrosion they protect against, but they are worth it over time.

Safety Features

Modern pumps have safety features in place that your town's older pumps may not have. It's wise to explore the features offered by each new pump you're considering. Optical signaling and safety diaphragms that prevent leaking of chemicals into the facility are two examples of features to seek. Dual alarm systems that alert users to a leak are also useful, as are relief valves that prevent overloading.

Adjustments for Viscosity Changes

Some of the chemical solutions used to treat wastewater may vary in viscosity depending on the temperature of the entire system. If you're using such chemicals, choose pumps that will automatically adjust for viscosity changes.

Recalibration Needs

Every metering pump will need to be re-calibrated periodically to ensure that the pump is still releasing adequate amounts of the chemicals it controls. Ideally, this happens manually whenever the pump is inspected for damage. However, in a busy facility, calibration may not happen unless a problem is suspected. Look for pumps that have very clear guidelines about how often they'll need to be re-evaluated for effectiveness.

With these details, ordering a new chemical metering pump is easier. You'll also have a plan in place for even more new pumps when the need arises. Check with other facility professionals and pump retailers for advice and information.