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Chemicals Used During Wastewater Treatment

Various Chemicals are used throughout the wastewater treatment process. These wide range of chemicals include substances high in alkalinity as well as, substances with high acidity. Due to the dangerous nature of these chemicals it is important to move them with a pump that will keep employees safe. Shanley pump offers our GemmeCotti magnetically driven plastic pump series to get the job done safely. The GemmeCotti mag-drive pump is constructed from PP and PVDF thermoplastics reinforced with fiber glass and carbon fibers, allowing them to continuously handle highly acidic or alkaline mediums. Most importantly the pump is seal less, meaning there is no shaft seal, this prevents leaking and costly repairs promoting both cost savings and safety. The most common chemical classes our pumps are used for in the wastewater treatment industry are coagulants, flocculants, neutralizing agents, disinfectants, and corrosion inhibitors.

Coagulants and Flocculants

Flocculation and coagulation treatment chemicals are used in processes for solid removal, water clarification, and sludge thickening. They are typically used successively, with the coagulant leading the way. The coagulant serves the purpose of neutralizing the charge of micro-suspended solids in water. Prior to the coagulant being added, these micro-solids share the same positive charge, and since similarly magnetically charged particles repel, the solids remain suspended within the water. Once the charge has been neutralized, the flocculant is added. Flocculants serve the purpose of causing the neutralized particles to lump together. The larger masses then either float to the top of the water or sink to the bottom due to gravity allowing for their easy removal. Commonly used coagulants are aluminum sulfate, sodium aluminate, polyaluminum chloride, and polyferric sulfate. Commonly used flocculants include cationic starch, chitosan, and polyacrylamides. Many people in the industry commonly generalize all chemicals used for coagulation and flocculation as “polymer”. Figure 1 shows the effect of coagulation and flocculation causing the suspended particles to clump and settle out.

Figure 1.

Flocculation and coagulation treatment chemicals

Neutralizing Agents

Neutralizing agents serve the purpose of adjusting the PH of wastewater. Federal and state regulations require specific PH ranges for wastewater discharge. PH regulation within the waste water treatment facility prior to discharge is also important as it enables other chemicals to work more efficiently. Popular chemicals used to raise the PH include calcium oxide, magnesium hydroxide, calcium hydroxide. Popular chemicals used to lower the PH include sulfuric acid and hydrochloric acid.


Disinfectants are used to kill disease-causing microorganisms. The most commonly used disinfectant in waste water treatment facilities is sodium hypochlorite (bleach); however, newer technologies are emerging to replace chemicals for the disinfection step of water treatment. Ozonation, or Ozone-sterilization, which is achieved through dissolved air flotation, also known as DAF. The small microbubbles produced in DAF act as a sterilizing agent that kills bacteria on contact. Shanley Pump offers our Edur DAF pump for water treatment plants that have taken a more environmentally friendly approach to disinfection.

Corrosion Inhibitors

Corrosion inhibitors are chemical products which when added to a fluid, slow down the rate of corrosion. This is done by forming a protective coating inside pipes in the distribution systems. This will ultimately prevent lead from leaching into drinking water. The most common inhibitor used in drinking water supplies is orthophosphate.

Shanley Pump

Shanley Pump keeps a large supply pumps for the wastewater treatment industry, allowing us to serve urgent water treatment pumping needs for nearly 50 years. Specifically our GemmeCotti magnetically driven pumps are great for chemicals such as polymer, while our SEP progressive cavity pumps, as well as our sister company Liberty Process’s Millennium Series Pumps are ideal for pumping high viscosity fluids frequently found in wastewater treatment plants. Call or email us below today to see how we can assist your wastewater treatment facility.

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*Shanley Pump Group is not affiliated with nor distributor for Seepex®, Allweiler®, Moyno®, Tarby®, Netzsch®, or Continental Inc.® all referenced product names, brands, models, or part numbers is solely for identification purposes. Seepex® is a registered trademark of Seepex®. Moyno® and Tarby® are registered trademarks of Robins and Myers® and NOV®, Netzsch® Incorporated is a registered trademark of the Netzsch® Group, Allweiler® is a registered trademark of Colfax® Corporations Continental® Pumps is a Trademark of Continental® Ultra Pumps.