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Struvite is a mineral compound made up of magnesium, ammonia and phosphorus, aka "MAP." The ingredients for Struvite crystal are found in the water of WWTPs because of the makeup of the human waste. Our drinking water contains a small minute amount of magnesium, but it gets a bit concentrated in the anaerobic digester. Urea from human waste breaks down into ammonia and carbon dioxide (CO2) in the anaerobic digester. Phosphorus comes into the plant as a phosphate from our dishwasher and laundry detergents. The anaerobic digester in combination with the pipes and pumps makes a terrific growth site for Struvite. When magnesium, ammonia and phosphorus come together in a one mole to one mole to one mole relationship in the WWTP or CAFO digester, Struvite precipitates. To prevent struvite formation, one has to keep the MAP components from developing into crystals.


Gii Scale Control

Wastewater treatment plant managers have found struvite crystal rock formations in many of the following plant areas:

  • Anaerobic digesters

  • Places where there is high kinetic energy (high turbulence)

  • Pipe connections – especially elbows

  • Pumps are a prime location

  • Valves

  • Aeration assembly

  • Internal pumping components

  • Plant overflow box of the anaerobic digester

  • Wastewater Sludge transfer line

  • Plant Centrifuges

  • Rollers of the Belt Press

Rough surface areas are one of the first areas to look for Struvite formation, when Struvite crystal rock is not 100% removed from the different surfaces, the remaining rough edges will form struvite more quickly.

Struvite Formation Tale Tell Signs

• High pH is a warning for the potential struvite formation
• High conductivity increases the potential for struvite formation
• Low temperatures foster the environment for struvite formation
• Higher concentrations of ammonium, phosphate and magnesium enable struvite precipitation

Waste Water Treatment Plants Use Gii Scale Control

Zero Chemicals

Eliminate Pressure Washing

Environmentally Friendly


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Reference Sites Are Available

Calcite: The No. 1 Culprit


Based on field studies and lysimeter tests, calcium was determined to be the dominant element responsible for the precipitate clogging. Carbonates, sulfates, iron, and phosphorous were also found to cause precipitate formation. These findings are consistent with other reported landfill clogging investigations. By assessing both leachate from existing landfills and leachate created under laboratory conditions, the team determined that clogging occurs when the equilibrium among calcium species is disrupted by microbial activity, the presence of additional minerals, and a change in oxidation conditions. At this stage of research, the rate of clog formation, the likelihood that the phenomenon will peak, and the extent of the formation over the life of the landfill are still unknown. Anaerobic bacterial activities in landfills will be present as long as the source of carbon and substrates exists. The team is hopeful that these questions will be answered through additional analysis and modeling efforts.


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