Homework Besides Those in the Textbook

Homework besides those in the textbook

1. Five million gallons per day (MGD) of a conservative substance, with concentration 10.0 mg/L, is released into a stream having an upstream flow of 10 MGD and substance concentration of 3.0 mg/L. Assume complete mixing.

(a) What is the concentration in ppm just downstream?

(b) How many pounds of substance per day pass a given spot downstream? (You may want the conversions 3.785 L/gal and 2.2 kg/lbm from the Appendix.)

2. A lagoon is to be designed to accommodate an input flow of 0.10 m3/s of nonconservative pollutant with concentration 30.0 mg/L and reaction rate 0.20/day. The effluent from the lagoon must have pollutant concentration of less than 10.0 mg/L. Assuming complete mixing, how large must the lagoon be?

3. A conventional aeration tank is to treat a flow of 3,000,000 m3/d of primary effluent with a BOD of 125 ppm. The MLSS concentration is to be maintained at 1800 ppm, and a food-to-microorganism ratio of 0.4 is specified. Compute the required volume of the aeration tank.

4. An aeration tank has a MLSS concentration of 2000 mg/L. After settling for 30 min in a 1-L graduated cylinder, the sludge volume is measured to be 150 mL. Compute the SVI of the sludge.

5. A sludge with 6% solids concentration occupies a total volume of 300 m3. (a) What is the water content of the sludge? (b) What is the mass of the sludge solids? (c) If the sludge is further concentrated (or dewatered) to a volume of 200m3, what will be the solids concentration be? What will be the water content be?

6. Visit and explore the EPACleanLakes Program Web page. Write a brief report about the program; describe that relationship between the Clean Lakes Program and the Nonpoint Source Management program.

7. Visit the Urban Stormwater-Best Management Practices Web page and link to the “Control Measures” section. In a brief written report, summarize both the advantage and disadvantages of dry detection basins and wet detection basins.

8. Visit and explore the EPA Office of Wastewater Management Web page. Search for and link to the “industrial Pretreatment” site. Write a brief report that summarizes the main elements of the National pretreatment program.

9. Visit the “Solid Waste Association of North America” Home page (SWANA). Link to the “SWANA Press Release” page; read the latest news story and write a brief summary of it.

10. Visit the EPA Office of Solid Waste Web page. Link to the Waste Cleanup page. Write a brief report explaining the difference between RCRA’s Superfund Program and the RCRA Corrective Action Program. Also, research and describe the pups of the “Battery ACT”.

11. Visit and explore the EPA Global Warming Site. Link to the “What’s in the NEWs” page. Read one of the recent documents and write a brief summary of what you learned from the article.

12. Visit and explore the EPA Office of Air and Radiation Web Site. Link to the “Indoor Air” Page and check out “What’s New at IAQ.” Read one of the documents and write a brief summary of what you learned from the article.

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