Question 1 The town of Lawrence has been directed to upgrade its primary WWTP to a...
2. [20] A small town has been directed to upgrade its primary wastewater treatment plant to a secondary plant that can meet an effluent standard of 25.0 mg/L BODs and 30.0 mg/L suspended solids. They have selected a completely mixed activated sludge system. The following data are available from the existing primary plant. Existing plant effluent characteristics Flow = 0.2000 m 3/s soluble BODs-80 mg/L Assume that the BOD5 of the suspended solids may be estimated as equal to 50%...
(30 points) A completely mixed activated sludge system comprised of an aerated reactor and a secondary clarifier with sludge return is going to treat 15,000 m/d of industrial wastewater. The primary effluent going to the reactor has a BODs of 1,100 mg/L that must be reduced to 150 mg/L prior to discharge to a municipal sewer. The pilot study was conducted and generated the following results: 3. Mean cell residence time- 5 day, MLSS concentration in the reactor 7.200 mg/L...
A wastewater treatment plant that treats wastewater to secondary treatment standards uses a primary sedimentation process followed by conventional activated sludge process composed of covered aeration tanks and secondary clarifiers. You are asked to calculate the different operation parameters to make sure that the system is operated within normal process ranges listed in the reference tables below. Table 5-20 Typical design information for primary sedimentation tanks U.S. customary units Item Unit Range Typical Primary sedimentation tanks followed by secondary treatment...
A flow of 2.6 med leaves a primary clarifier with a BOD of 131 mg/L. Determine the sludge age of the facility given the following data: aeration tank volume is 2300 m, MLSS concentration is 2100 mg/L, efluent suspended solids are equal to 20 mg/L, and the mass rate of wasted solids is equal to 44 percent of the BOD load. A flow of 2.6 med leaves a primary clarifier with a BOD of 131 mg/L. Determine the sludge age...
2. A completely mixed activated sludge process is designed to treat 20,000 m/d of domestic wastewater having a BODs concentration of 250 mg/L following primary treatment. The NPDES permit requirement for effluent BODs and TSS is 20 mg/L for each. The biokinetic parameters have beern established as: yield 0.6, k 5/d, K-60 mg/L, and kd 0.06/d. The MLVSS concentration in the aeration tank is to be maintained at 3000 mg/L and the ratio of VSS/TSS is 0.75. Assume that the...
A completely mixed activated sludge plant is designed to treat 10,000 m3/d of an industrial wastewater. The wastewater has a BOD5 of 1200 mg/L. Pilot plant data indicates that a reactor volume of 6090 m3 with an MLSS concentration of 5000 mg/L should produce 83% BOD5 removal. The value for Y is determined to be 0.7 kg/kg and the value of kd is found to be 0.03 d–1. Under ow solids concentra- tion is 12,000 mg/L. The ow diagram is...
A complete-mix activated sludge system is used to treat municipal wastewater after primary sedimentation at 20 °C with MLVSS concentration of 2000 g/m3. The discharge standard for soluble BOD, concentration in the effluent is 0.5 g/m. The characteristics of the primary influent are: flow Q -2000 m'/d, soluble BOD -200 g/m3, Using these data and the kinetic coefficients in following, determine 1. Theoretical solids retention time (SRT) in unit of days 2. Pk vss in unit of kg VSS/d 3....
For the completely mixed activated sludge process shown below, the system boundary is shown by the dash line. Qis the wastewater flow rate into the aeration tank; Q, is the flow rate of liquid containing microorganisms to be wasted: X is the microorganism concentration (VSS) entering the aeration tank: X is the microorganism concentration (MLVSS) in the aeration tank; X is the microorganism concentration (VSS) in the effluent from secondary settling tank X, is the microorganism (VSS) in sludge being...
1. A circular secondary clarifier (a.k.a. a final clarifier) is to be designed for an activated sludge treatment plant serving a municipality. The state regulatory agency criteria for final clarifiers used for activated sludge are: Peak SOR = 1,200 gal/day-ft2 Average SOR = 500 gal/day-ft2 Peak solids loading 50 lb/day-ft Peak weir loading-30,000 gal/day.ft The average flow to the aeration basin prior to junction with the recycle line is 3.5 MGD ·The recycled sludge flow is 30 percent of the...
Situation (note: Problem 2 is not linked with Problem 1): Assuming the design flow rate of raw wastewater to be treated is 20 MGD in the design year, the dissolved BODs is 380 mg/L, and SS is 360 mg/L. The wastewater generated by the sludge treatment process is about 4 MGD with the dissolved BODs being 1800 mg/L, and SS being 1200 mg/L, and will be returned to the wet well in the pumping station at the beginning of the...