A vegetable processing plant discharges its wastewater to a treatment pond with an area of 10,000 m³ and a depth of 3 m. The wastewater has an organic content of 350 mg/L and a flow of 1.8 m³/min. Laboratory studies show that the waste decays according to first order kinetics with a rate constant of 0.031/h at 20 °C. (a) What is the hydraulic detention time (0)? (b) If the pond is assumed to be completely mixed, what is the steady state effluent concentration in winter when water temperature is 10°C? The temperature correction coefficient (0) is 1.072

A vegetable processing plant discharges its wastewater to a treatment pond with an area of 10,000 m³ and a depth of 3 m. The wastewater has an organic content of 350 mg/L and a flow of 1.8 m³/min. Laboratory studies show that the waste decays according to first order kinetics with a rate constant of 0.031/h at 20 °C. (a) What is the hydraulic detention time (0)? (b) If the pond is assumed to be completely mixed, what is the steady state effluent concentration in winter when water temperature is 10°C? The temperature correction coefficient (0) is 1.072

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

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 settling tank having a depth of 3.5 m and surface area of 1000 m2 is used to remove particles of size 0.01 mm and specific gravity of 2.7. Calculate the removal percentage of the tank for a discharge of 7000 m3/d. Take viscosity of water as 10-3 kg/m.s.
A settling tank (32 m long, 2.1 m across and 1.6 m deep) is used to clarify water containing particles with a diameter of 120 µm. The density of the particles is 2.5 g/cm3 and the dynamic viscosity of water is 1.3 x 10-2 g/cm.sec. What is the maximum flow rate that can be allowed to make sure all the particles settle in the tank?
A reactor with predominantly longitudinal dimension has reaction volume of 3,000 m3.The influent has flow rate of 600 m3/day and concentration of Na+200 g/m3 and BOD 200 g/m3. Please answer the following:a. What is the hydraulic retention time? b. What would be concentration decay model along the relative length x=L/L0? c. If it is an ideal plug flow reactor, please calculate the concentration profile along the length of the reactor, e.g., x=0.2, 0.4, 0.6, 0.8, and 1 of the total length if Na+ is a conservative species while BOD is degradable specie with reaction rate constant k = 0.4/day. d. Please plot the concentration profile vs. relative length x for Na+and BOD, respectively.
A lake has an inflow and outflow of 20x10^6 m^3/yr, a mean depth of 10 m and a surface area of 10x10^6 m^2. Waste is discharge to the surface layer at a rate of 10^5 gm/day. The upper 3 m of the lake form a well-mixed epilimnion while the remainder is mixed more slowly at a vertical dispersion rate of 1 m^2/day. What is the well-mixed concentration in the epilimnion and predict the concentration at the bottom of the lake as a function of time. How long can you use this model?
It takes 30 hours for water to flow from Point A to point B in a river. The flow rate and BOD5 in the river are 10 m^3/hr and 2 mg/L, respectively. A wastewater of flow rate 2 m^3/hr containing BOD5 of 30 mg/L is discharged into the river at point A. Calculate the BOD5 concentration at downstream point B by treating the river as 20 CMFRs in series with equal hydraulic detention times. The first order decay coefficient k of the BOD5 is assumed to be 0.065/hr.
A treatment plant has a horizontal flow sedimentation basin with a depth of 4 m, width of 6 m, and length of 36 m. It has a process flow rate of 400 m3/h. Assuming all the particles have a diameter of 0.0029 cm and a particle density of 2650 kg/m3 and they are in water at a temperature of 10°C, would the process remove all of them?
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.
An underground storage tank leaks tetrachloroethylene (PCE) at a rate of 100 mL/d (about the volume of a small lemon per day). This continues for one year before the leak is discovered and stopped. The tank lies at the water table, so all of the PCE released enters the sand aquifer (but isnot necessarily immediately dissolved in the groundwater). The aquifer is 4.0 m deep and composed of sand. The actual groundwater velocity (average linear velocity) is 0.09 m/d, and the hydraulic gradient is 0.0005. The retardation factor for PCE is 6.(a) What is the hydraulic conductivity of the aquifer?(b) How far would you expect the PCE to have traveled down gradient during the one-year period?
A chemical tanker truck crashes into a flooded, abandoned quarry (no soil or sediment on the bottom). It was carrying 1000 kg of benzene which is all released into the quarry and quickly becomes a completely mixed system. The quarry is 10 m deep and has a surface area of 10,000 m2. The quarry is fed by a spring with a constant temperature of 20°C and water flows out of it to a local stream at a flow rate of 10 m3/min. (a) How long will the concentration in the quarry violate the applicable NJ Surface Water Quality Standards (FW2) (assume only loss is flow out)? (b) If bacteria is introduced to the quarry that can consume benzene following a 1st order decay process with a decay constant k = 0.01 day-1, how long will the concentration in the quarry violate the regulations?
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
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