You need to design a treatment 200 pts The plant for flowback water from Marcell

Question

You need to design a treatment 200 pts The plant for flowback water from Marcellus Shale drilling. The well produces 1 MGD. water coming out of the plant contains 200 ppm ultimate BoD with a pH 6 7. The first step is to raise the pH of the water to precipitate some of the salts. You are going to mix the flowback water with another stream containing water at a pH of 12 in a csTR. If you want the combined stream to have a pH of 9.5, calculate the flowrate of the incoming stream. Assume no reaction. (Hint: Do a material balance on OH.) (10 pts) 8 need the pH GPD After treating the water you to decrease to 6. The water is held in a100,000 gallon-pondr. You have a 0.5 Macid solution with a How many mls of this solution are required to change the pH from 9.5 to 6? (10 pts) mL

Explanation / Answer

One way to test for contamination in water from lakes, rivers and streams is with a bioassay.

A bioassay uses a living organism--usually a plant or a bacteria--as a test agent for the presence or concentration of a chemical compound or a disease. The idea is to choose a test agent that is very sensitive to the condition you are testing.

Have you ever read about how miners took canaries down into mines to act as early warnings of gas leaks? Because canaries are more sensitive to gas than people, the birds reacted to very small amounts of gas and gave miners a chance to escape. You could say canaries were a bioassay for underground gas.

Different plants are often used as bioassays because they respond in a predictable way and are often very sensitive to the condition that is being tested. A standard toxic dose--the level at which no seeds of the bioassay plant sprout or all the plants die--is established as a reference point. Then samples are tested and compared to the reference standard.

Of all the possible water-quality bioassay organisms, lettuce might be one of the last you would think of. Lettuce doesn't live in water, so why use it to test water quality? The reason is lettuce bioassays are inexpensive, easy to do, and the seeds are pretty sensitive to some types of contaminants in water, including heavy metals, pesticides and other organic toxins. Although any variety of lettuce may do, Lactuca sativa Buttercrunch is the standard variety recommended for bioassays by the U.S. Environmental Protection Agency, the Food and Drug Administration, and the Organization for Economic Cooperation and Development.

You might try taking a series of samples along one stream or compare streams near industry to water running though agricultural areas

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