WATER TREATMENT PLANT FLOW & TREATMENT

The Lima Water Treatment Plant receives raw water from four upground reservoirs. To the west of Lima, water from the Auglaize River is used to fill the 4.9 billion gallon Bresler Lake Reservoir. On the east side, a complex consisting of Ferguson, Metzger Lake and Lost Creek Reservoirs is filled from the Ottawa River. The total storage capacity of the east side complex is approximately 4.0 billion gallons.

At the treatment plant, potassium permanganate, activated carbon, or chlorine dioxide can be added to the incoming water as needed for both disinfection and for taste and odor control. The water then flows into a 2.5 million gallon primary treatment basin (see photo) where clarification and softening chemicals can be added. Water flows from the primary treatment basin into two secondary basins (1.3 million gallons each). This process allows time for the water to react with taste and odor control chemicals which were added earlier. Additional softening and clarification chemicals can be added at this stage if needed.

Clarified and softened water leaves the secondary basins and flows to a 40,000 gallon chamber where carbon dioxide is added to stabilize the water. When leaving this stabilization basin, a polyphosphate is added to provide additional water stability.

Water continues through the plant to a bank of ten rapid sand filters. Here, water is filtered through a combination of anthracite coal, sand, and a mixture of support gravel. The filters remove any remaining suspended matter present in the water.

Water leaving the sand filters is chlorinated, fluoridated, and a second polyphosphate is added to enhance water stability in the distribution system. The water then flows into a 4.8 million gallon storage well. Water is pumped from this storage well using four electric pumps and one diesel driven pump (in case of power failure) to meet the city's water needs.

Plant operators monitor and control the system using a programmable logic controller (PLC) based computer system. PLC's are also used to control and monitor the reservoir systems.