The City of Lima Wastewater Plant treats an annual average of just over 13 million gallons of sewage a day and can treat a peak flow of 70 million gallons per day. The treatment plant receives a combination of domestic and industrial sewage as well as storm water. Approximately 60% of the city’s sewers are combined which means they carry both sewage as well as storm water to the plant for treatment. That wastewater is carried to the plant through over 200 miles of sewer lines and 32 pump stations.
Wastewater treatment is the process of removing contaminants from wastewater by converting it into clean effluent water prior to being returned to the water cycle by being discharged into the Ottawa River. This conversion process takes place over several stages of treatment. In preliminary and primary treatment, things like grit, large debris and heavier solids are removed through screening and primary settling. At this point the sewage still contains organic and some inorganic waste. The secondary stage of treatment is where biological processes are used to further breakdown the organics and clarify the water. Finally the solid that are separated during these treatment processes are stabilized through the digestion process, dewatered and can then be used for agricultural fertilizer or landfilled. The clean water is disinfected to kill any remaining pathogens and then discharged into the stream. The ultimate goal of wastewater treatment is the protection of human health and keeping our Ottawa River and Ohio’s other waterways clean and safe for recreational use.