Quiz for export-WRE

Enter your response in the box. A two-stage granular activated carbon (GAC) column is used to reduce the influent concentration of 10 mg/L of a chlorinated compound-contaminated groundwater to an effluent concentration of 0.1 mg/L. The equilibrium adsorption capacity (qe = x/m) was experimentally determined to be 6.6 mg/g. where, x = mass of solute adsorbed and m = mass of adsorbent

A storm sewer collects 300,000 gal/day of water having an average aluminum concentration of 1.3 mg/L. A fraction of this water can be discharged to a nearby creek, subject to the constraints of the following water quality standards:

Other point sources in the area discharge 16.72 lb/day of aluminum. Therefore, the minimum amount of storm water (gal/day) that must be retained and not discharged via a single outfall to a nearby creek is most nearly:

An ultrafiltration membrane is being evaluated for a community that experiences winter temperature of 5°C and summer temperature of 30°C in the source water. The membrane manufacturer reports a membrane porosity of 0.7, membrane pore size of 0.04 μm, and a membrane thickness of 1 mm. If the net transmembrane pressure is maintained year round at 1 N/m² , the change in volumetric flux (m/s) due to temperature variation that the membrane will experience is most nearly:

The liquid temperature of the sludge pumped to an aerobic digester at a wastewater treatment plant is 25°C. To achieve a 45% volatile solids reduction in the digester, the required sludge age (days) is most nearly:

For which group will increasing any of the compounds increase the hardness of water?

The groundwater near an industrial spill contains 2 μg/L of chlordane. The organic carbon partitioning coefficient for chlordane is 330 mL/g. The concentration (mg/kg) sorbed to a soil containing 0.5% organic carbon is most nearly:

A lake has a surface area of 160 acres. The average inflow for a 31-day month is 45 cfs, and the outflow is 43.9 cfs. The precipitation for the month is 3.1 in., and the evaporation is 2.0 in. The exfiltration out of the lake is estimated to be 0.01 in./day. The change in volume (acre-ft) for the month is most nearly:

Use the NRCS method for an area with a curve number of 80. The amount of a 9-in. rainfall that turns to runoff is most nearly:

Enter your response in the box. Water flows steadily at a velocity of 8 ft/sec through a circular pipe with a diameter of 3 in. The pipe diameter increases such that the resulting flow velocity through the larger circular pipe is only 2 ft/sec.

A Venturi meter is used to measure water flow in a 36-in.-diameter horizontal pipe. The throat diameter is 12 in., and the coefficient of velocity is 0.985. The pressure differential between the pipe and the throat is measured as 4.2 psi. The flow rate (ft³/sec) in the pipe is most nearly:

Fill in the blank with a word “greater” or “smaller”. Water is flowing up a hill from an elevation of 30 ft to an elevation of 40 ft.

A pipeline carrying 2.0 cfs of water at 68°F divides at Point A as shown in the figure. The following information is given:

The flow rate (cfs) in Pipe 1 is most nearly:

A PVC sanitary sewer has an inside diameter of 24 in. (area = 3.14 ft²). The depth of flow is 6 in. The Manning’s roughness coefficient n is equal to 0.012 and may be assumed to be constant with depth. The channel slope is 0.005. If the flow rate is 2.37 ft³/sec, the velocity (ft/sec) is most nearly:

Which of the following is not needed to compute net positive suction head available (NPSHA)?