A fish processing plant produces and discharges a waste brine solution with salinity (salt content) of 10 % NaC1 (conservative material), at a rate of 500 L/min. The stream flows at a rate of 5 million L/d upstream of the brine discharge point and has a salinity of 10 mg/L. Downstream of the discharge point is a prime spot for the fishing sport, and the fish are intolerant to salt concentrations above 200 mg/L. (a) What must the level of salt in the processing plant effluent be to reduce the level in the stream to 200 mg/L and (b) If the fish processing plant has to spend $ 8 million to reduce its salt