ABC Wastewater Treatment Class II case studies
ABC Wastewater Treatment Class II · Put your knowledge to work in context.
The ABC Wastewater Treatment Class II credential is a mid-level operator certification for people who run conventional wastewater treatment plants and are ready to take on more process responsibility than a Class I role. It is typically pursued by operators who already have hands-on plant experience and want formal recognition of their ability to run primary and secondary treatment, manage solids, and keep equipment and reporting in line. The ABC Wastewater Treatment Class II case studies are 5 cases and about 2,419 words.
1Rising Sludge Blanket After Aeration Basin Flow Shift
A conventional activated sludge plant treats 1.8 MGD average flow. Aeration basin volume is 1.0 MG, so the design hydraulic retention time is about 13 hours.
527 words, about 3 min2Chlorine Demand Spike Before Discharge Permit Limit
A 2.5 MGD secondary plant disinfects with sodium hypochlorite in a contact chamber designed for 30 minutes at peak flow. The discharge permit requires fecal coliform below 200 CFU/100 mL (geometric mean) and total residual chlorine below 0.1 mg/L at the outfall.
498 words, about 2 min3Digester Foaming and Gas Production Drop
A mesophilic anaerobic digester receives primary and waste activated sludge at about 4 percent solids. For two weeks the gas production has fallen from 9,000 to 6,500 cubic feet per day, and the digester has developed a thick foam layer that is entering the gas line.
483 words, about 2 min4Pump Cavitation and Seal Failure on Sludge Transfer
A centrifugal sludge transfer pump moves thickened sludge from a gravity thickener to a digester. The pump has recently started making a rattling noise, and the discharge pressure gauge fluctuates.
474 words, about 2 min5Sampling and Reporting Pressure After an Inconsistent DMR
A small plant submits a discharge monitoring report monthly. The permit requires weekly fecal coliform samples and daily pH and flow.
437 words, about 2 min