When water pumped from the pump station reaches the filtration plant, chemicals are added to it in the flash mix. These chemicals aid in coagulation and flocculation, control corrosion of pipes, reduce organics, and benefit dental health. After the chemicals are added, the water is slowly stirred by sets of flocculators that decrease in speed along the treatment path, allowing particles in the water to stick together and sink to the bottom of the settling basins. The water is then filtered by nine high-rate, dual media filters which we currently use to filter up to eight million gallons per day.
The Danville Water Treatment Plant, constructed in 1924, treats water pumped from Herrington Lake by way of a pump station located near Gwinn Island Marina that was constructed in 1935. Over the years the original treatment plant has been upgraded several times to reach its current treatment capacity of 10 million gallons per day.