Direction: An activated sludge system (sketched below) is operating at equilibrium with the following information. Waste water related data: flow rate = 500 m³/hour, influent BOD = 150 mg/l, effluent BOD = 10 mg/l. Aeration tank related data: hydraulic retention time = 8 hours, mean-cell-residence time=240 hours, volume = 4000 m³, mixed liquor suspended solids = 2000 mg/l. Influent, Aeration tank Secondary Effluent clarifier Sludge recycle Solids wasted 2. The mass (in kg/day) of solids wasted from the system is

Direction: An activated sludge system (sketched below) is operating at equilibrium with the following information. Waste water related data: flow rate = 500 m³/hour, influent BOD = 150 mg/l, effluent BOD = 10 mg/l. Aeration tank related data: hydraulic retention time = 8 hours, mean-cell-residence time=240 hours, volume = 4000 m³, mixed liquor suspended solids = 2000 mg/l. Influent, Aeration tank Secondary Effluent clarifier Sludge recycle Solids wasted 2. The mass (in kg/day) of solids wasted from the system is

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

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How to determine the needed surface area of the secondary clarifier tank given that the flow is 40,000 m3 per day and the recycling ratio is 0.5 . The necessary solids concentration in the underflow is 13,000 mg/L, while the Mixed liquor suspended solids concentration in the activated sludge is 4,500 mg/L. Hint: Plot SFg= CiVi then Use SFL equation to get the area The table below shows the settling properties of sludge: Mixed liquor suspended solids Mg/l Settling velocity m/hr 2000 6 4000 3 6000 1 8000 0.2 10000 0.1 13000 0.1
How to determine the needed surface area of the secondary clarifier tank given that the flow is 40,000 m3 per day and the recycling ratio is 0.5 . The necessary solids concentration in the underflow is 13,000 mg/L, while the Mixed liquor suspended solids concentration in the activated sludge is 4,500 mg/L. The table below shows the settling properties of sludge: Mixed liquor suspended solids Mg/l Settling velocity m/hr 2000 6 4000 3 6000 1 8000 0.2 10000 0.1 13000 0.1
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:
After conventional filtration, the filtered water with turbidity less than 0.5 NTU, pH =7 and T=5 C on a day when the peak hourly flow is 4.0 mgd (million gallon per day). After filtration, the water is chlorinated in a contact with hydraulic characteristics shown in Figure 11.20 b. What is the applied chlorine dose if free chlorine is used for disinfection?
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
The influent suspended solids concentration to a primary settling (clarifier) tank is 300 mg/L. The average flow rate is 0.037 m3/s. If the suspended solids removal efficiency is 65 percent, how many kilograms of suspended solids are removed in the primary settling tank each day?
Assume that DLSUD lake is 100m2 and its average height is 5ft. Wastewater that flows into the lake are the following: Food square kitchen waste 7 m3/sec; Total Dissolved Solids (TDS) is 25,000 mg/L which operates 8hrs per day CIH 5m3 /hr kitchen waste; TDS is 20mg/L which operates 4hrs per day PCH 20m3 /day diluted laboratory waste ; TDS = 40mg/L (1)Determine the volumetric flow rate of the lake water can still accommodate prior to rainfall.
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an accumulation test is used to determine: a) evaporation rate b) furnace volume c) how much money you have accumulated d) safety valve capacity
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
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
Calculate the minimum fluidization velocity for an anthracite bed having following characteristics; d90 = 2.9 mm, ?anthracite = 1600 kg/m3, ?water = 998 kg/m3 at 20°C; µ = 1.002x 10-3 kg/m.sec