Originally designed for a 0.75 MGD capacity, the Grantsville Wastewater Treatment Plant receives residential wastewater from almost 10,000 residents in Grantsville, Utah, just west of Salt Lake City. In 2009, the plant was having significant trouble meeting the city’s discharge requirements for ammonia, TSS, and BOD. According to Ron Griffin, the plant’s operator, treated wastewater would violate discharge requirements so regularly that he had to store it six months out of the year to limit violations. “Something within every six months was a problem — either our ammonia or our BOD,” Griffin said. “So, I was only discharging six months out of the year. I would discharge for three months, hold for three months, discharge for three and then hold for three.”
Upon further evaluation, Environmental Dynamics International (EDI) proposed using an Intermittently Decanted Extended Aeration Lagoon, or IDEAL™. IDEAL is a lagoon-based extended aeration system that treats raw wastewater using a batch reactor process. The IDEAL process allows continuous inflow of raw wastewater, which then undergoes a sequenced aeration reaction/mixing phase, followed by a settling phase. Finally, the water is decanted and discharged to polishing ponds.
After removing the existing surface aerator from the primary pond, construction workers installed the IDEAL. Equipment required for the upgrade included EDI’s floating lateral aeration system with FlexAir 88S assemblies paired with Magnum fine bubble diffusers, a BioReef™ BioCurtain, and four 24-inch diameter decant pipes with electric actuated valves, system control panel, and three 220 HP turbo blowers. During construction, workers were met with a significant challenge: A 4-ft sludge blanket in the bottom of the cells. Griffin said, “We had to pull about 30 different blocks that held the old surface aerators in place, and they had to be eliminated so we could put in these deep, fine bubble diffusers.”
Project Type: Municipal
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