CVEN 5534

Final Assignment

Spring 2005

The Louisville Wastewater Treatment Plant (WWTP) currently receives residuals from the town’s drinking water treatment plants: filter backwash water containing alum floc and entrained particulates removed from source water during treatment. Data on the alum sludge wasting to the plant is attached and on the class website.

Currently, the total suspended solids concentration in the water treatment plant (WTP) flow ranges between 300 and 800 mg/l (ppm). Note that the conversion between pounds of solids/day, flow rate (MGD), and concentration is:

Assume the alum concentration in the WTP flow is 20 mg/L as Al.

Alter your BioWin configuration of the Louisville WWTP to take in the WTP residual flow. Both the flow and TSS in the WTP stream should be added to the current flow rate and influent constituent data.

  1. Show the plant schematic with the WTP residuals flow and compare with your earlier process configuration for the WWTP with no residuals flow.
  1. Discuss the impact of the current WTP residuals addition on process performance (effluent BOD, nitrogen species, phosphorus, and suspended solids). (Comparing with the no-residuals case you simulated previously.)
  1. Discuss the impact of the WTP residuals at current loading rates on waste solids generated at the WWTP in the aerobic digester and the dewatered sludge. (Comparing with the no-residuals case you simulated previously.)
  1. Discuss the impact of the WTP residuals at current loading rates on the activated sludge biomass (in the anoxic and aeration basins), including MLSS, MLVSS:MLSS, , total and specific oxygen uptake rates, and nitrate uptake rate. (Comparing with the no-residuals case you simulated previously.)
  1. What is the aluminum concentration in the effluent, in the MLSS, and in the biosolids?

Part II

  1. The maximum permitted plant capacity for the WTP residuals is 4,200 lb-TSS/day.
  1. Assuming that the concentration of TSS and aluminum in the WTP residuals flow do not change, calculate the WTP residuals flow rate that would accompany an increase in TSS to 4,200 lb/day. Assume that the anoxic/aeration basin MLSS concentration cannot exceed 4,000 mg/L.
  1. Show the BioWin configuration and report for the maximum WTP residuals flow.
  1. Discuss the impacts of the increased residuals discharge on the effluent water quality, biosolids production rate and characteristics, and aeration/anoxic basin operating characteristics, compared with the current influent sewage and WTP residuals flows.
  1. Discuss what changes to process operations (if any) would have to be made to receive the maximum permitted WTP residuals and stay within permitted WWTP operation.