literature review, you find that the chemical is toxic to aquatic life at a concentration of 5 ppb. The city of Pinewood is located 4.5 km downstream of the chemical plant and uses the river as a drinking water source. Data provided: 10 m3 day 3,500 m3 day1 25 m2 5 ppb Flow rate of wastewater to be discharged to the river Flow rate of the river Cross-sectional area of the river Limit of toxicity to aquatic life Limit required for use as a drinking water source 1 ppt Your first task is to determine how the chemical degrades in the river water. You send a sample of the river water to a contract laboratory and ask them to conduct a batch reactor degradation experiment. They send you the following data: Time (days) Measured concentration (mg L-?) 0 10.0 2 5.90 4 2.87 1.76 10 0.33 b) Calculate the maximum concentration of the chemical that could be present in the wastewater in order to achieve a concentration in the river less than 5 ppb and a concentration less than 1 ppt in the Pinewood drinking water intake, whichever corresponds to the LOWER discharge concentration. Provide your answer in units of mass concentration. (10 points) c) Calculate the volume of a completely mixed flow reactor that is needed to treat the wastewater before it is discharged, in order to meet a maximum concentration in the effluent of 5 ppb. (6 points) d) The chemical plant operators come to you and request that during the summer months, they be able to discharge the wastewater at a concentration of 2 ppm because the water is warmer, and thus the chemical degrades faster in the river. During the summer, water in the river is 4 C warmer and this results in a reaction rate constant that is 25% higher. Will you tell the operators yes they can, or no they can't? Justify your decision with calculations. (10 points) literature review, you find that the chemical is toxic to aquatic life at a concentration of 5 ppb. The city of Pinewood is located 4.5 km downstream of the chemical plant and uses the river as a drinking water source. Data provided: 10 m3 day 3,500 m3 day1 25 m2 5 ppb Flow rate of wastewater to be discharged to the river Flow rate of the river Cross-sectional area of the river Limit of toxicity to aquatic life Limit required for use as a drinking water source 1 ppt Your first task is to determine how the chemical degrades in the river water. You send a sample of the river water to a contract laboratory and ask them to conduct a batch reactor degradation experiment. They send you the following data: Time (days) Measured concentration (mg L-?) 0 10.0 2 5.90 4 2.87 1.76 10 0.33 b) Calculate the maximum concentration of the chemical that could be present in the wastewater in order to achieve a concentration in the river less than 5 ppb and a concentration less than 1 ppt in the Pinewood drinking water intake, whichever corresponds to the LOWER discharge concentration. Provide your answer in units of mass concentration. (10 points) c) Calculate the volume of a completely mixed flow reactor that is needed to treat the wastewater before it is discharged, in order to meet a maximum concentration in the effluent of 5 ppb. (6 points) d) The chemical plant operators come to you and request that during the summer months, they be able to discharge the wastewater at a concentration of 2 ppm because the water is warmer, and thus the chemical degrades faster in the river. During the summer, water in the river is 4 C warmer and this results in a reaction rate constant that is 25% higher. Will you tell the operators yes they can, or no they can't? Justify your decision with calculations. (10 points)
