Estimate the reduction in bacteria during the passage of wastewater that initially contains 106 organisms per milliliter through three stabilization ponds that are arranged in series. The volumes of the three ponds are 10,000, 20,000, and 6000 m³, respectively. The flow rate is 1000 m³/d. Assume that steady-state conditions apply, that the ponds are mixed completely because of wind action, that first- order decay kinetics apply, and that the value of the reaction rate coefficient k is 1.0 d ¹. Would the efficiency improve if all of the ponds were equal in volume (12,000 m³/pond)?

Estimate the reduction in bacteria during the passage of wastewater that initially contains 106 organisms per milliliter through three stabilization ponds that are arranged in series. The volumes of the three ponds are 10,000, 20,000, and 6000 m³, respectively. The flow rate is 1000 m³/d. Assume that steady-state conditions apply, that the ponds are mixed completely because of wind action, that first- order decay kinetics apply, and that the value of the reaction rate coefficient k is 1.0 d ¹. Would the efficiency improve if all of the ponds were equal in volume (12,000 m³/pond)?

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

In an activated sludge treatment system, the BOD concentration decays according to first order kinetics, with a decay constant k BOD= 1.5 h-1. The flowrate is 1.010 3m3/d, and the volume of the activated sludge system is 100 m3. If the BOD concentration entering the system is 100 mg/L, what is the BOD concentration in the effluent (in mg/L)? Report using the correct number of SIGNIFICANT FIGURES. You can model the treatment system as a plug flow reactor.
1) Design a UASB reactor to treat wastewater at 30°C from a food processing plant. The wastewater fow rate is 500 m3/d with a solubleCOD concentration of 6000 mg/L. The design parameters are asfollows:Reactor effectiveness factor (E) = 0.85Upfow velocity = 1.2 m/hOrganic loading rate = 12 kg sCOD/m3 ·dY = 0.08 kg VSS/kg CODkd = 0.03 d–1μmax = 0.25 d–1Ks = 360 mg/LHeight for gas collection = 3 mUsing the given information, determine the following:a. The reactor area and diameterb. The reactor liquid volumec. Liquid depth and total height of the reactord. The average SRT (assuming 97% degradation of sCOD)
1) Design a UASB reactor to treat wastewater at 30°C from a food processing plant. The wastewater fow rate is 500 m3/d with a solubleCOD concentration of 6000 mg/L. The design parameters are asfollows:Reactor effectiveness factor (E) = 0.85Upfow velocity = 1.2 m/hOrganic loading rate = 12 kg sCOD/m3 ·dY = 0.08 kg VSS/kg CODkd = 0.03 d–1μmax = 0.25 d–1Ks = 360 mg/LHeight for gas collection = 3 mUsing the given information, determine the following:a. The reactor area and diameterb. The reactor liquid volumec. Liquid depth and total height of the reactord. The average SRT (assuming 97% degradation of sCOD) 2) Determine the methane gas production rate (m3/d) for the reactorfrom problem 1) Assume COD equivalent of VSS equals 1.42 kgCOD/kg VSS.
2 A groundwater (Q1 = 5.0 L/s) reaches a point of convergence (mixing) in a river (Q = 1.0 m3/s) where an industrial wastewater discharge (Q2 = 10 L/s) also converges. /s). If the groundwater has ferrous iron with concentration [Fe2+] = 10.0 mg/L, the industrial wastewater has organic matter with concentration TOC = 50 mg/L, determine the COD of the river downstream of the mixing point.
X=0 C = 6 mg/L at X=? A wastewater treatment plant discharges to a stream at X-0 as shown above. At the mixing point, the dissolved oxygen in the stream is 2.0 mg/L, which is too low for fish. They want a minimum of 6 mg/L. If the gas transfer coefficient is 0.4/day and the stream velocity is 3.6 mi/d, at what point downstream (X) will the DO be 6 mg/L? Assume the saturation concentration is 11 mg/L. (Hint: This is a plug flow reactor. In lab you did your measurements on a batch reactor, but remember that PFRS and batch reactors act the same mathematically.) Answer to one decimal place.
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
A storage tank of a treatment water has a holding capacity of 750 m' up to an overflow point. The treatment water having silica content of 0.003 mg /L is flowing in to a tank at a rate of 30 L/sec. the out flow from the tank to the high pressure boilers is 30 L/sec. With time the quality of treatment water increased to 0.025 mg/L. Assuming that the inflow in to and out flow from the tank remains constant at 30 L/sec, calculate the time required for the silica content in the storage tank to increase to 0.01 mg/L.
Q.5. The design flow for a water treatment plant (WTP) is 1 MGD. The rapid mixing tank will have a mechanical mixer and the average alum dosage will be 35 mg/L. the theoretical mean hydraulic detention time of the tank will be 60 seconds. Determine the following: 1-The quantity of alum needed on a daily basis in kg/d, 2-The dimensions of the tank in meters for a tank with equal length, width and depth, 3- The power input required for aggo Go of 900 seê' forawa te Tempreature of lóc (M=1•307*15°N• s/mz express The a $is wer in kw
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.
3. Consider the design of a wastewater treatment plant (WWTP) for a community with the following design data: TABLE 1: Design Data Design data Flow-0.150m³. s-¹ Influent suspended solids-280mg L-¹ Influent BODs = 500mg L-¹ -1 Sludge concentration= 6.0% Efficiency= 60% Effective length= 40.0 m Width = 10.0 m Liquid depth = 2.0 m Weir length= 75.0 m Table 2: Acceptability Criteria Parameter Detention time (hours) Overflow rate (m- day) Weir loading (m³-day m¹') Acceptable range 1.5-2.5 80-120 <250 (c) Assume that the primary sedimentation process in this treatment facility removes 60% of the suspended solids (SS) and 40% of the BODs of the raw sewage. Determine the SS and BOD5 concentrations in the primary sedimentation effluent flow.
Two wastewater streams A and B, having an identical ultimate BOD are getting mixed to form the stream C. The temperature of the stream A is 20 °C and the temperature of the stream C is 10 °C. It is given that The 5-day BOD of the stream A measured at 20 °C-50 mg/l BOD rate constant (base 10) at 20 °C=0.115 per day Temperature coefficient = 1.135 The 5-day BOD (in mg/l, up to one decimal place) of the stream C, calculated at 10 °C, is X EE
Problem 4. A water treatment plant has six settling tanks that operate in parallel (the flow gets split into six equal flow streams), and each tank has a volume of 40 m³. a) If the flow to the plant is 10 million gallons per day, what is the residence time in each of the settling tanks? b) If instead, the tanks operated in series (the entire flow goes first through one tank, then the second, and so on), what would be the retention time in each tank? c) The suspended solids concentration is 100 mg/L at the inlet of the plant. Assuming a first-order removal rate for suspended solids in the settling tanks with a rate constant k = 0.1 min-'. What would be the suspended solids concentration at the outlet of the plant when the settling tanks are operated in parallel? d) What would be the suspended solids concentration at the outlet of the plant when the settling tanks are operated in series?