Q- ASP is used to treat a waste water flow of 2MLD having BOD5 of 250 mg/lit. The biomass concentration in the aeration tank is 2500 mg/lit and the concentration of biomass leaving the system is 80 mg/lit, the aeration tank has a volume of 200m³. Find the hydraulic retention time HRT.

A complete mix activated sludge process is to be used for biological treatment. This plant receives 10,000 m³ of wastewater per day with BOD loading of 250 mg/L. The primary treatment efficiency is 25%. Assume the followings: ● ● -4- Plant effluent BOD5 = 12 mg/L Biomass yield = 0.54 kg biomass / kg BOD Endogenous decay rate=0.05 day-¹ Solids Retention Time = 8 days MLVSS concentration in the aeration tank = 2,700 mg/L Waste and recycle solids concentration = 12,000 mg/L Determine the followings: (i). The hydraulic detention time in hours. (ii). The aeration tank volume in cubic meters. ...4/- SULIT EAP582

Wastewater is treated with an activated sludge plug flow reactor, similar to one seen at the Norman Water Reclamation Facility. The BOD5 after primary treatment is 100mg/L and the effluent limit is 5 mg/L BOD5. Use 1.00 h-1 as the maximum specific growth rate constant and typical values for the other biokinetic constants. The biomass concentration in the reactor is 2,500 mg/L MLSS based on a recycle ratio of 1. Calculate the mean cell residence time, in hours for this system

An activated sludge wastewater treatment system was designed and operated in a steadystate under the following conditions:• Reactor volume of 10,000 m3in total;• Sludge concentration (MLSS) of 3200 mg/L in the reactor;• Return sludge concentration at 8000 mg/L (the underflow of the secondary clarifier)• Each day, 400 m3 of underflow sludge (return sludge) was wasted as excesssludge;What is the average Sludge Residence Time (SRT)?