The City of Kalamazoo Water Reclamation Plant (KWRP) provides treatment services to more than 150,000 residents in 18 Kalamazoo-area municipal jurisdictions. The KWRP uses an innovative treatment system to treat a variety of pollutants in concentrations that most other plants cannot. The plant incorporates powdered activated carbon (PAC) treatment into its secondary process, which enables treatment of wastewater from a variety of industries without the need for pretreatment.
The KWRP receives a significant portion of its wastewater from industrial sources. Manufacturers that produce pharmaceuticals, organic chemicals, spices and food additives, as well as projects associated from groundwater clean-up and remediation of contaminated groundwater directly benefit from the PAC process. By providing these businesses with state-of-the-art, unique wastewater treatment, the KWRP helps the community attract and retain employers who offer opportunities to residents.
Staff are available to provide free plant tours (by appointment only) throughout the year. Tours usually last approximately 2.5 hours. More information on the KWRP is available in this informational brochure or by contacting the administrative office at (269) 337-8701.
Customer service for water and sewer utility customers (including billing, payments, shut-offs for non-payment, transfers of service, and new service installation) is provided by the Treasurer's Office, located on the first floor of City Hall. Representatives are available weekdays between 8:00 a.m. and 4:30 p.m. in person or by calling (269) 337-8149. Customers can pay their utility bills in person, by phone, or online. More information on payment options is available from the City Treasurer's Office.
Wastewater treatment process
As the wastewater enters the plant, it is screened to remove large debris contained in the flow. Unless removed, this debris could damage equipment in the facility further in the process. The wastewater is then pumped to the primary treatment facilities. Computerized control of the pumps stabilizes the flow rate and loading to downstream processes.
The municipal primary treatment facilities consist of two processes. Screening is the first of these processes and consists of two parts. First, grit is removed as the wastewater flows through two grit tanks. The heavy grit particles settle to the bottom of the tank and air, which is injected into the flow, creates a spiral motion and ensures that lighter organic solids are not removed with the grit. The second part takes the flow through any of three fine screens to remove the smaller floating solids. The second primary treatment is sedimentation. Wastewater flows to any of six sedimentation tanks. Here, under quiescent conditions, settleable solids are removed from the wastewater. The settled solids are moved to one end of the tank and pumped to the solids treatment facilities.
Secondary treatment with powdered activated carbon
At this point, primary treatment effluent flows to the secondary treatment facility, which is designed to remove dissolved and finely divided impurities. This process is often referred to as "biological treatment" since it utilizes various microorganisms to treat the wastewater.
In secondary treatment, the wastewater is combined with bacteria and powdered activated carbon (PAC) to make a slurry called "mixed liquor". This slurry flows through Anaerobic, Anoxic, and Aerobic conditions to remove phosphorous and nitrogen biologically in large rectangular basins. Bacteria use the organic solids as food for metabolism and production of new cellular material. PAC plays an important role, since it absorbs those impurities which inhibit bacterial growth or are not easily "digested" by bacteria. It also acts as a weighting agent to enhance settling characteristics. Additionally, PAC improves nitrification by improving surface area for the microorganisms. Fine bubble diffusers are utilized to improve oxygen transfer efficiency and reduce energy consumption.
Carbon and bacteria are removed by settling in clarification tanks, which follow the aeration process. The settled slurry of bacteria and PAC are removed from the bottom of the tank and returned to the beginning of the secondary process. A portion of the slurry is again combined with wastewater entering the secondary treatment facilities and the remaining portion of the returned slurry is pumped to the solids treatment facility.
Tertiary treatment and filters
Tertiary treatment consists of ten gravity sand filters which remove small suspended solid particles and fugitive carbon remaining from secondary treatment. In order to reach the filters, the wastewater must be lifted by five screw pumps at the Tertiary Pump Station.
The tertiary filters remove solid particles as the wastewater passes through the small voids in the sand, and the solid particles that become trapped on the filter surface are removed by backwashing. The filtered water is then chemically disinfected to destroy disease causing organisms. Following disinfection, the flow is dechlorinated prior to discharge in the Kalamazoo River.