The waste flow 18000m³/day is treated by activated sludge process to reduce 97.5% of influent BOD5 concentration of 250mg/L .the ratio of formed cell mass and substrate utilized mass are 0.4 and 0.8 respectively, MLVSS=3500mg/L, return sludge (X,)=8000mg/L, decay growth rate=0.05 and 0-10 days, Find the following: 1.Reactor volume and hydraulic retention time. 3. The daily amount of wasted sludge. 2.The volumetric organic loading

A wastewater treatment uses an activated sludge process for secondary treatment of 0.3 m^3/s of primary effluent. The activated sludge has a biomass concentration of 2,100 mg VSS/L, and the return activated sludge line (also known as RAS) concentration is 10,000 mg VSS/L. The substrate concentration in the primary effluent is 220 mg BOD5/L. The F/M ratio for the activated sludge tank is 0.52 mg BOD5 × mg VSS^-1 × d^-1 , and the cell residence time is 9.0 d. (a) What is the volume of the activated sludge tank?(b) What is the waste line (also known as WAS) flow rate?(c) What is the flow rate of the effluent from the entire system?(d) What is the hydraulic residence time for the activated sludge tank? Hint: You will need to also write a mass balance for biomass X around the secondary clarifier, and a flow balance around the secondary clarifier, as part of the solution.

A reservoir of liquid waste has a mass of 1200 kg and volume of 0.952 m3. Find its : i. Weight ; ii. Density ; iii. Specific weight and; iv. Specific gravity

For an industrial activated sludge treatment process, the biomass concentration (X) is 2,200 mg VSS/L and the substrate concentration (S) is 50 mg BOD5/L. Using the following values, find the net microbial growth rate (rg').Max substrate utilization rate (k) = 5 mg BOD5/mg VSS-dHalf saturation constant (Ks) = 60 mg BOD5/LMicrobial yield coefficient (Y) = 0.6 mg VSS/mg BOD5Endogenous decay (death) rate constant (kd) = 0.06 /d

A wastewater treatment plant discharges 0.1 m3/s of treated wastewater to a river having a mean flow rate of 25 m3/s. The biological components of the wastewater have a concentration of 15 mg/l in the waste stream and are consumed by bacteria in the river with a rate constant of k = −0.3 d-1. 1. Ignoring the biological reaction, what is the pure physical dilution downstream in the river after the waste discharge is fully mixed across the cross-section of the river?

You are the lead engineer on a wastewater treatment plant with a biological reactor. You are required todetermine how much biomass will be produced in kg per day in your plant. A junior engineer determines theultimate BOD of the incoming waste as 600 mg/l, with a decay constant of 0.1/d. The incoming substrateconcentration used should be the five-day BOD. The incoming flow is 75 m3/d however there are lossesupstream of the plant accounting for 15 m3/d of the flow. The target BOD discharged from the plant is 25mg/l. the kinetic constants for the system are Ks = 90 mg/L BOD5, kd = 0.2 d-1, μm = 1.5 d-1, and Y = 0.6 mg VSS/mgBOD5. Include a sketch to illustrate the biological reactor and its incoming flows.

A stream containing no biochemical O2 demand (obviously a hypothetical situation) has a DO of 5.00 mg/L and a flow rate of 8.70 m3/s.  The temperature of the stream is 15 degrees Celsius.  The average velocity in the stream is 0.174 m/s.  The average depth is 5 m.  Determine the reaeration coefficient and the rate of reaeration.

If the BOD of a municipal wastewater at the end of 7 days is 60 mg/L and the ultimate BOD is 85.0 mg/L, what is the first order reaction constant?

A river has ultimate BOD of 60 mg/L, a width of 20 m, a depth of 5 m and a flow rate of 9 m3/s. A waste at 20°C having ultimate BOD of 250 mg/L, a decay rate constant of 0.1/day, and flow rate of 1 m% is discharged into the river. The river and the waste are at the same temperature of 20°C and contain the same pollutant (same decay rate constant). If there is instantaneous mixing of the waste in the river, determine:a. Ultimate BOD in the river immediately after mixing of the waste mixed with the river. b. The value of BOD in the river five days after mixing of the waste with the river. c. BOD concentration in the river at 50 km downstream from the point of discharge.d. BOD removed at 95 km downstream from the point of discharge

Dissolved oxygen (D0) is influenced by which factors? Explain. How can you determine chloride content in a waste water sample?             Subject: Enviromental Engineering 2 lab