The river near a town with a population of 150, 000 (note: not the town of Waterville above) has a very big flow rate to allow the town to build a new DWTP. The surface water quality is as follows: (1) average TSS of 10000 mg/L; (2) 35 mg/L of calcium bicarbonate and 20 mg/L of magnesium bicarbonate; and (3) during the spring runoff season, the river may be contaminated by low concentrations of synthetic organics (such as atrazine). Assuming you are hired by the town as an engineer to design a DWTP with an average flow in the design year being 50 MGD.

Requirements:
Do your design based on the design year only by (1) identifying the treatment train of the new DWTP that uses the river water as its supply; (2) identifying the locations where chemicals are added (but not their quantities); and (3) sizing your major reactors that are located before the disinfection process. For example, if you have rapid mixing tanks, flocculation tanks, and sand filters, you need to calculate their sizes, but don’t need to get into the design details (e. g., design of paddle wheels, sand filter underdrain system, clean sand head loss, backwash hydraulics, etc.). In addition, you don’t need to include the design of the pumping station, bar rack design, clear well design because they will be designed by the other engineers in your group.