Kalamazoo Water Reclamation Plant

All of the water that flows into a toilet or drain ultimately ends up at Kalamazoo's Wastewater Reclamation Plant for treatment. After it leaves your home or business, wastewater naturally flows towards the KWRP because the system is designed to be driven by gravity. As it gets closer to the plant, the elevation decreases, and smaller pipes connect into larger ones. By the time wastewater enters the plant, its two stories underground.

There are lift stations located in areas where the gravity alone cannot get wastewater all the way to the plant. These stations elevate the wastewater stream so it can resume its flow downhill for treatment.

When wastewater first enters the plant, it is screened to remove any large debris or objects that are in the flow. If not removed, these could damage pumps or equipment in the facility. The wastewater is then pumped to the primary treatment facilities. Computer control stabilizes the flow rate for downstream processes. 

Wastewater is screened again during primary treatment to remove finer solid materials. First flows through two grit tanks that allow heavier particles to settle to the bottom of the tank. Then it flows through finer screens to remove smaller suspended solids.

From here, wastewater flows into one of six sedimentation tanks. Any remaining material suspended in the water settles and is pumped to the solids treatment facilities. 

After primary treatment, the wastewater flows to the secondary treatment facility, which removes dissolved and finely divided impurities. Micro-organisms are added to the wastewater along with powdered activated carbon. This mixture flows through anaerobic, anoxic, and aerobic conditions to biologically remove phosphorous and nitrogen. Micro-organisms use the organic solids as food for metabolism and production of new cellular material.  The powdered activated carbon absorbs impurities in the wastewater that inhibit the micro-organisms or are not easily "digested". It also acts as a weighting agent to improve settling and improves nitrification by improving surface area for the micro-organisms. Fine bubble diffusers are utilized to improve oxygen transfer efficiency and reduce energy consumption. 

From here, the wastewater moves into clarification tanks. The carbon and micro-organisms that were added settle to the bottom of the tank and are removed. Some of this material is reused in the secondary process. The remaining portion is pumped to the solids treatment facility for disposal.

Tertiary treatment is the final step in the wastewater treatment process. The water passes through ten gravity sand filters that remove small suspending particles and trace amounts of carbon that remain from secondary treatment. In order to reach these filters, the water must be elevated by screw pumps. 

The tertiary filters remove solid particles as the water passes through the small voids between the grains of sand. The particles that become trapped in the filter are removed by back washing. The filtered water is then chemically disinfected, dechlorinated, and discharged to the Kalamazoo River.