Study villa

Study villa

The City of Villa Rica, Georgia, located in Carroll County, has two wastewater treatment plants. The West WWTP is a new 2.15 MGD facility designed for future expansions. Key features of the plant design include a new influent raw sewerage pump station; an oxidation ditch with a multi-stage selector ahead of the ditch for biological phosphorus and total nitrogen removal; clarification. Tertiary treatment, including tertiary clarification and a deep bed sand filter; an auto-thermal thermophilic aerobic digestion system (SNDR secondary by Thermal Process Systems, Inc.).

And a plant drain pump station. This facility operated well until the early morning of June 1, 2016, when potential disaster struck. A pipe broke in the basement of the SNDR System and drained 235,000 gallons of highly concentrated sludge onto the floor, which was then pumped back to the headworks via the drain pumps. The exact concentration of this sludge was not known; however, it had been treated for an extended period of time to process a Class A sludge.

Study Material

The biological ditch was severely damaged, resulting in phosphorus levels jumping up to 75 mg/L (typically < 1 mg/L), alkalinity and pH dropping severely and ammonia reaching extremely high levels. Although the personnel at the plant had aluminum chloride (ACS) on site, they knew it would not handle this loading. Pete Zorbanos, Villa Rica Public Works Director, contacted Nuclear Inc. (NCI), and NCI's team made a site visit at 11:00 a.m. the same day and performed jar testing to determine the basin chemistry and devise an emergency treatment plan. 

The NCI team quickly mobilized and began feeding NCLEAR™ crystals into the clarifier influent (oxidation ditch effluent @ splitter box) at 7:00 pm that evening.  Plant personnel collected samples frequently and increased the lime feed and aeration at the head of the oxidation ditch to help with the pH, alkalinity, and ammonia problems. The NCLEAR™ crystals quickly reduced the phosphorus in the clarifiers, filters, and effluent discharge. The Return Activated Sludge (RAS) from the clarifiers, containing NCLEAR™, returned to the head of the plant where the crystals began increasing the pH and alkalinity, helping to reduce the ammonia and reducing the phosphorus by approximately half every day. Within six days the Villa Rica West WWTP was back operating normally.