well for treatment. Each primary settling tank has a 24 inch effluent pipe that is connected to a 30 inch cast iron pipe that directs the effluent to the aeration tanks. The primary tanks also have an 18 inch cast iron by-pass line that connects to the plant outfall line. Each settling tank is 42' 0" X 14' 0" X 10' 3" SWD with a sludge hopper on the north end of the tank. Waste Water is fed into the north end of each tank through a series of gates and the effluent flows over the H-shaped weir at the south end of the tank. A scum removal trough is located just north of the effluent weir. Sludge is scraped into the hoppers and a cross collector screw moves the sludge to the north end for removal.

PRIMARY SLUDGE REMOVAL

Sludge is drawn off each settling tank through 6 inch cast iron pipes to the sludge pits using telescoping valves and then returned to the pump and control building through a 6 inch suction line where the primary sludge is pumped to the primary digester.

AERATION

The effluent from the primary settling tanks and the returned activated sludge from the final settling tanks are discharged to the influent channel at the same central location. The influent can be fed to each tank from the influent channel on the north end of the tanks or it can be diverted to an aerated channel that runs the length of the tanks and then fed into one tank. The aeration tanks are 126' 0" long X 24' 0" wide X 14' 0" SWD and are all interconnected below the water level. A 16 inch air supply line from the blower building is diverted to two 14 inch headers to supply air to the aeration tanks. Fine bubble diffusers are used for the aeration system. Effluent weirs are located on the south end of each tank. The effluent over the weirs is channeled to a 36 inch cast iron pipe which connects to the final settling tanks.

FINAL SETTLING TANKS

A branch line diverts flow to all four final settling tanks. Each tank is 56' 0" long X 16' 0" wide X 10' 6" SWD with a sludge hopper on the south end of the tank. Wastewater is fed into the south end of the