. Design and activated sludge process to treat 10MGD of domestic sewage having a BODs of 210 mg/liter, produce an effluent containing less than 15 mg/liter BODs. Assume a complete mix reactor. Use the following data in design. X, 10,000mg/liter, MLVSS=3,000mg/liter, 0,= 8 days, Y=0.60, kg 0.05, Efflunet SS-10 mg/liter Determine: (a) Biological treatment efficiency, (b) Reactor volume, (c) sludge production rate, (d) Recirculation ratio, (e) Hydraulic retention time, (f) Food to microorganism ration. (30 points)

. Design and activated sludge process to treat 10MGD of domestic sewage having a BODs of 210 mg/liter, produce an effluent containing less than 15 mg/liter BODs. Assume a complete mix reactor. Use the following data in design. X, 10,000mg/liter, MLVSS=3,000mg/liter, 0,= 8 days, Y=0.60, kg 0.05, Efflunet SS-10 mg/liter Determine: (a) Biological treatment efficiency, (b) Reactor volume, (c) sludge production rate, (d) Recirculation ratio, (e) Hydraulic retention time, (f) Food to microorganism ration. (30 points)

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

See similar textbooks

Similar questions

It is desired to design an activated sludge process to treat 20,000 m3/d of settled wastewater with a BOD of 250 mg/L and nbVSS concentration of 10 mg/L. If the effluent BOD is not to exceed 20 mg/L, calculate the volume of the aeration tank required, sludge wastage rate, sludge return rate, oxygen requirements, F/M ratio, specific utilization rate, specific growth rate, and maximum specific growth rate. The following data and coefficients are applicable. i. Mean cell residence time = 5 daysii. Y = 0.5 gVSS/g BODiii. Kd = 0.10 /div. K = 5 /dv. Return sludge concentration = 8,000 mg/L VSSvi. Mixed liquor volatile suspended solids concentration = 2500 mg/Lvii. Effluent contains 20 mg/L suspended solids of which 65% are biodegradable.viii. Fraction of biomass remaining as cell debris = 0.15ix. BOD5/BODu = 0.68
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 BOD5 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 m3 /s soluble BOD5 = 80 mg/L Assume that the BOD5 of the suspended solids may be estimated as equal to 50% of the suspended solids concentration, the microorganism concentration in the aeration tank (MLVSS) is 2000 mg/L, and the net activated sludge produced is 400.0 kg/d; also assume the following values for the growth constants: bacterial decay rate = 0.10 day-1 , yield coefficient = 0.60 mgVSS ∙ mg-1 BOD5 removed, maximum specific growth rate constant = 2.50 day-1 , and half saturation constant = 100 mg/L. (1) Estimate the volume of the aeration tank; (2) Compute the F/M ratio; (3) If the BOD5 is 60% of the ultimate…
An activated sludge plant with recycle is evaluating its secondary clarification system. Settling column tests are conducted and analyzed for settling velocities at different initial solids concentrations. The data are provided below. The plant flow rate is 10,000 m3/d, with a recirculation ratio of 0.5. The MLSS in the reactor is 4000 mg/L. The desired underflow concentration is 17,000 mg/L. Solids concentration mg/L Settling velocity m/h 1500 6.5 3000 5.1 4500 4 6000 2.95 7500 2 9000 1.4 12,000 0.5 15,000 0.27 17,000 0.2 a. Calculate the required surface area if one clarifier is used. b. Calculate underflow rate, underflow velocity, and overflow rate for single clarifier design. Clearly state your assumptions. c. Calculate the required surface area if two clarifiers are used
Solid removal efficiency in a primary settling tank has been measured as %30 which is very low value. Jar tests showed that if 120 mg/L FeCl 3 is added into the wastewater, the solid removal efficiency will be around 75%. Using the data presented below, compute the total amount of sludge produced daily in the primary settling tank in terms of mass and volume. Wastewater flow rate: 8.000 m3 /dayTotal solid concentration: 300 mg/LSolid content of sludge: 4 %Specific gravity of sludge: 1,02 Molecular Weights (g/mole);Ca:40 – C:12 – O:16 – H:1 – S:32– Al:27 – Fe:56 - Cl:35,5 – P:31
A wastewater treatment plant processes its mixed sludge by employing the gravity thickening followed by anaerobic digestion. The thickened sludge has a flowrate of 4,000 m³/d at a solids content of 5% and must be conveyed over a 100m-long pipeline (Hazen-William coefficient C = 100) between the gravity thickeners and anaerobic digesters. Size the diameter of the pipe and estimate the friction headloss using both simple multiplication factor method and rheological method, respectively.
The shrimp processing plant generates 0.012 m3/s of wastewater each day. The wastewater is treated in an activated sludge plant. The average BOD5 of the raw wastewater before primary settling is 1400 mg/L. The aeration tank has effective liquid dimensions of 8.0 m wide by 8.0 m long by 5.0 m deep. The plant operating parameters are as follows: Soluble BOD5 after primary settling = 966 mg/L MLVSS = 2000 mg/L MLSS = 1.25 (MLVS) Settled sludge volume after 30 min = 225 mL/L Aeration tank liquid temperature = 15°C Determine the following: Return Activated Sludge (RAS) flow rate and Wasting Activated Sludge (WAS) flow rate.
A water contains a suspended solids concentration of 6.5 mg/L. Coagulation/flocculation and sedimentation reduce the solids concentration to 1.5 mg/L. Ferric chloride (FeCl3•7H2O) is used as the coagulant at a dose of 50 mg/L. a. How many kg of sludge are produced per day for a 12 MGD treatment plant? b. How much alkalinity is consumed in mg/L as CaCO3?FeCl3•7H2O + 3HCO3- = Fe(OH)3(s) + 3CO2 + 3Cl- + H2O
A wastewater treatment plant will receive a flow of 30,000 m3/day. The plant has a 3.6 m deep circular primary clarifier with a surface overflow rate of 60.0 m3/m2-day.a. Calculate the surface area (m2), diameter (m), volume (m3), and hydraulic retention time of the primary clarifier.b. How long will it take a 1.0 mm particle with a density of 1500 kg/m3to settle in the primary clarifier? show all work
Given:Flow rate of water = 500 L/minSuspended solids concentration in influent water = 100 mg/LRequired effluent suspended solids concentration = 10 mg/LFiltration rate = 10 m^3/m^2/hrFiltration tank dimensions: Length = 5 m, Width = 3 m, Depth = 4 mCalculate:o Calculate the total suspended solids (TSS) load in the influent water:o Calculate the filtration tank surface area:o Calculate the required filtration tank capacity:o Calculate the required detention time in the filtration tank: Q2) DisinfectionGiven:Flow rate of water = 2000 m^3/hChlorine residual required in effluent = 0.5 mg/LInitial chlorine concentration in influent water = 2 mg/LChlorine decay rate in disinfection tank = 0.05 per hourDisinfection tank volume = 300 m^3Calculate:o Calculate the chlorine demand in the influent water:o Calculate the chlorine dosage required:o Calculate the chlorine dosage rate:o Calculate the actual chlorine dosage rate considering chlorine decay:
a) An activated sludge plant with recycle is evaluating its secondary clarification system. Settling column tests are conducted and analyzed for settling velocities at different initial solids concentrations. The data are provided below. The plant flow rate is 10,000 m3/d, with a recirculation ratio of 0.5. The MLSS in the reactor is 4000 mg/L. The desired underflow concentration is 17,000 mg/L. Solids concentration mg/L Settling velocity m/h 1500 6.5 3000 5.1 4500 4 6000 2.95 7500 2 9000 1.4 12,000 0.5 15,000 0.27 17,000 0.2 b) Design secondary clarifiers for the activated sludge plant of problem a), with a recycle ratio of 0.6. Calculate the required surface area if two clarifiers are used. Also calculate underflow rate, underflow velocity, and overflow rates. Clearly state your assumptions.
The aeration tank for a completely mixed aeration process is being sized for a design wastewater flow of 4500 m³/d. The influent COD is 150 mg/L. The design effluent COD is 7 mg/L. Recommended design parameters are a sludge age of 10 days and MLVSS of 1400 mg/L. The expected Sludge Volume Index is 100 ml/g. The selection of these values takes into account the anticipated variations in wastewater flows and strengths. The kinetic constants from a bench-scale treatability study are Y = 0.60 mg VSS/mg COD and ke = 0.06 per day. Calculate: a. the hydraulic residence time and volume of the aeration tank b. the food/microorganism ratio c. the sludge production rate d. the sludge recycle ratio e. the oxygen requirement
A wastewater with a BOD of 25mg/L is discharged through an outfall to a freshwater stream of mean velocity 0.1m/s. The DO downstream of the outfall is 8.5mg/L. Assume the deoxygenation rate is 0.25/d, the reaeration rate is 0.4 /d and the temperature of 20 degree C (DOs = 9.09mg/L). Compute for the ff: a) Critical distance b) minimum DO c) Oxygen deficit d) Critical time