You are investigating the water quality of a river with an average velocity of 30 m/min and a sewage discharge which impacts the dissolved oxygen in the river. It is linear and regular for a length of 100 miles, except there is a small waterfall 10 miles downstream of discharge. At the waterfall, the oxygen deficit falls back to zero. The load to the river is 20 mg/L. The de-oxygenation rate coefficient (kj) is 0.3 day and the re-aeration rate coefficient (k,) is 0.5 day'. If the initial oxygen deficit is 0 mg/L and oxygen saturation is 8 mg/L, what is the minimum concentration seen in the river?

You are investigating the water quality of a river with an average velocity of 30 m/min and a sewage discharge which impacts the dissolved oxygen in the river. It is linear and regular for a length of 100 miles, except there is a small waterfall 10 miles downstream of discharge. At the waterfall, the oxygen deficit falls back to zero. The load to the river is 20 mg/L. The de-oxygenation rate coefficient (kj) is 0.3 day and the re-aeration rate coefficient (k,) is 0.5 day'. If the initial oxygen deficit is 0 mg/L and oxygen saturation is 8 mg/L, what is the minimum concentration seen in the river?

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

Problem 5Suppose there is a river that has a flow rate of 3.00 m3/s with negligible concentration of sodium chloride and astream discharges into this river at a flow rate of 0.05 m3/s. The concentration of sodium chloride of the out flowafter mixing is to be 1.0 mg/L.1. What should be the inflow concentration of sodium chloride in the stream to maintain a steady statecondition? Consider a completely mixed system.2. Calculate the mass rate (kg/d) of the sodium chloride in the stream?
Reportedly one of the shortest rivers in the world at 30 m in length, the Ombla River watershed hasan area of about 600 km2 and receives 1020.8 mm of precipitation annually. The regional averageannual evapotranspiration is 150 mm. Measured at its Adriatic Sea terminus, the average flowrateof the Ombla River is 24.1 m3/s.How much runoff reached the river as discharge for the year (in cm)? What annual volume is removed in vapour form (in m3)?Considering the climatic variables reported, what volume remains unclassified in the waterbalance (in ha∙m/yr), and what could this volume reasonably represent in the hydrologic cycle?
A new water treatment plant is going to be constructed in Jacksonville to replacethe existing plant. The average annual water temperature is 19 oC. The following designassumptions for a flocculation tank have been made:Number of tanks = 1Detention time = 40 minVelocity gradient = 25 s−1Impeller type: radial, 3 flat blades, Np = 0.33Impeller diameter = 1.1 mRotational speed = 30 rpmWhat is the design flow rate in m3/d?
Wastewater of 30ft3/s with a biochemical oxygen demand (BOD) of 55mg/l, and dissolved oxygen (DO) of 3.3mg/l enters a river where the flow is 125ft3/s with an ultimate BOD of 7.0 mg/l, and DO of 6.8mg/l. The downstream has an average velocity of 0.8ft/s. i . Calculate the minimum DO level and its distance in miles downstream using the oxygen sag equation. Assume k1 = 0.046 per day and k2 = 0.304 per day. The saturation DO = 8.5mg/l. (1 mile = 5280ft) ii. At what distance downstream would the DO level of the river be equal to 6.10 mg/l? iii. How much should the wastewater DO be increased to maintain a minimum DO of 4.8mg/l anywhere along the river. Assuming that the BOD of the wastewater and the river flow remains the same?
The average hourly water consumption per person is 2.5 Liters anf there are 264 people in the area. Determine the following. a. the minimum rate of flow in L/s in the spring b. Total Daily water demand in L/day c. Determine if its daily yield is sufficient to the water demand of the community if the rate of flow of the spring is 0.182L/s d. the height of the cylinder in cm thatt the minimum discharge can fill within 300 secs. diameter of the cylinder is 10 cm
A tannery with a wastewater flow of 0.011 m3/s and a BOD5 of 590 mg/Ldischarges into the Cattaraugus Creek (Nemerow, 1974). The creek has a10-year, 7-day low flow of 1.7 m3/s. Upstream of the tannery, the BOD5of the creek is 0.6 mg/L. The BOD rate constants k are 0.115 d21 for thetannery and 3.7 d21 for the creek. The temperature of both the creek andthe tannery wastewater is 208C. Calculate the initial ultimate BOD aftermixing.
a drainage basin with an area of 5 km2 receives 25 mm ofrainfall. The losses due to interception and evaporation during the rainfall event amountis 5 mm. There is also some surface runoff. There is 2% of the rain falls directly falls intothe stream as channel precipitation. A very large part of the rainfall infiltrates into thesoil. The amount of 40000 m3 of volume of water discharges at the out let of thewatershed, where 75% of this amount is baseflow. What is the runoff coefficient (%)?Hint (Runoff coefficient is surface runoff/precipitation)
A flow of 8.5 m3/sec occurs in a long rectangular channel 3 m wide, laid on aslope of 0.0016, and having n = 0.018. There is a smooth gradual constriction inthe channel to 1.8 width. what depths may be expected in and just upstream fromthe constriction. Show your answers on the specific energy diagram.
A wastewater treatment plant discharges an effluent containing 2 mg/L of dissolved oxygen to ariver that has a dissolved-oxygen concentration of 9 mg/L upstream of the discharge. Calculatethe dissolved-oxygen deficit at the mixing basin. Assume that the river and plant discharge havethe same flow rate and DO at saturation is 9 mg/L.
The community of San Antonio is located in the Caranavi Province, Bolivia. According to the 2005 year survey, there are 420 habitants of the community. The population is estimated to increase to 940 by the year 2035. The average peak flow is currently 1.2 L/sec and is expected to increase to 2.14 L/sec by 2035. The organic load is estimated to be 45 gram BOD5/capita-day. The community is considering a free surface wetland to treat their wastewater. (a) What is the BOD5 loading generated in the year 2035 (kg/day)? (b) Use the BOD loading to estimate the maximum surface area (ha) required for a free surface wetland that would serve the community in 2035 and remove BOD to 30 mg/L. (c) Assuming you are now considering sizing a facultative lagoon instead of a free surface wetland. Quickly estimate the required surface area (m2) for a facultative lagoon to handle a peak flow in 2035, assuming a design water depth of 4 m and a hydraulic detention time of 20 days.
Probability plotA bridge will be built over the Meherrin River near the site that the discharge measurements were taken for the log-normal probability plot below. The service life of the bridge is 40 years. If a design discharge of 23,000 cfs is used for the bridge: (a) what is the probability that the bridge will be flooded in any one year? (b) What is the probability that the bridge will be flooded at least once over its service life? (Note: just focus on the “theoretical line” in the plot)
A manufacturing facility that manufactures printed circuit boards puts washwater that was used to wash solvents from the circuit boards into a septic tankwhich discharges into ground water. The wash water contains 7.34 mg/L of dissolved trichloroethylene (TCE). The daily rate of discharge is 13.6 m'/day. Theunderlying aquifer has an average linear groundwater velocity of 0.34 m/day.The discharge has been going on long enough so that steady state conditionshave been reached. Assuming no degradation of the TCE, what is the concentation at a monitoring well located 22 meters downgradient of the septic tankdischarge (* = 22 m, y = 0 m)? Assume a value for b.