Question

I know this is multiple questions, I am going to post it six times each time asking for a different question, but I also know these questions build off each other so I couldn't just post the prompt and one question without the others.

Please answer question 4 (or it all :D)

An existing industrial wastewater treatment plant fails to treat a new chemical, pentachlorophenol, leaving the facility in its waste stream. A concentration of 100 μg/L pentachlorophenol now passes through the wastewater treatment plant and is released into the Willimantic River (a class B water) that is stocked with trout. UConn draws drinking water from a well field adjacent to the Willimantic River. The wastewater treatment plant releases an average flow of 0.2 MGD into the river. The average flow of the Willimantic River just upstream
of the treatment plant is 100 cfs (ft3/s). Based on the chemical nature of pentachlorophenol, it adsorbs to the sediment as it travels downstream, resulting in a loss rate of about 0.01/day.
Answer the following questions:
1. Draw the system, a control volume, and label all knowns and unknowns, inputs, outputs, sources or transformations.
2. Identify the regulations that apply to the contaminant in this scenario and state the specific regulation and the maximum concentration that should not be exceeded to protect aquatic life and human health.
3. What are the risks posed by the contamination in this system? Identify all concerns you may have given the contaminant and the exposure in the environment. Justify this based on research on how the contaminant behaves in the environment and how people use the river.
4. Calculate the maximum concentration of pentachlorophenol in the stream right where it enters the Willimantic River. Draw what the concentration (y-axis) would be in the stream vs. distance and vs. time (x-axis). Estimate and justify any other parameters you may need.
5. Estimate at what distance downstream will the contaminant concentration meet the aquatic life criteria?
6. Research and explain two treatment processes that could be installed at the treatment plant to reduce the pentachlorophenol concentration. Explain the process and why it works for this particular chemical.

Answer 1

Graphs:

COncentration vs time:

Concentration vs distance:

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