A 3 mgd oxidation ditch in Eastern Pennsylvania experienced a harsh winter with temperatures below 50°F. As a result settling was poor, around 900 mg/L, BOD, TSS, pH all were normal for the plant. An augmentation program was started with Toler-X 4100 adding 10 lbs per day for 2 days, 5 lbs per day for 3 days then maintaining 3 lbs per day.
After 2 weeks settling was reduced to 700 mg/L. As temperatures warmed up and augmentation continued after 6 weeks settling was reduced to 350 mg/L. This healthy dose of carbaneous bacteria was essential to efficient BOD removal and setting the stage for nitrification. High ammonia had been a problem as well, but with temperatures below 50°F augmenting with Nitrifiers was not recommended. In April as treatment continued to improve and temperatures increased the high Ammonia was addressed. As of April 16th, NH3 was 13.1 mg/L with a permit of 6 mg/L. BioRemove 5805 blend of Nitrosomonas and Nitrobacter was added to the aeration tank at 10 lbs per day for 4 days. The ammonia dropped within 6 days to 6.20 mg/L. By the end of the month NH3 was 0.22 mg/L with the monthly average being 6.69 mg/L, just slightly above the permit. In May the ammonia permit dropped to 2 mg/L. Even though the plant was nitrifying within permit the operator decided to add 1 more 10 lb jug of BioRemove 5805 to give the plant one final boost to assure the monthly average of 2 mg/L would be met.
Eastern PA WWTP