Kalamazoo City
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Facility Design

The Kalamazoo Water Reclamation Plant (KWRP) has the reputation of producing some of the best effluent - or clean water - in the state. Kalamazoo expects to continue this record of excellence.

While the KWRP has not reached its operational limits, there are two critical factors to consider. The first factor is the capacity of its physical structures. Flow into the KWRP averages 25 million gallons per day (MGD). This is less than half of the maximum design flow of 53.5 MGD, leaving plenty of room to grow and accept more flow. About half of this flow comes from industrial and commercial users such as large manufacturers and hospitals. The balance of the flow comes from residential customers, schools, and other industries.

The second critical factor is biological treatment limitations. The KWRP operates an "activated sludge" wastewater processing system. The activated sludge process is a living biological process. Activated sludge contains different types of microorganisms. These microorganisms, commonly called "bugs", are as important to the treatment of wastewater as any piece of equipment. Activated sludge treatment is a complex process that requires healthy bugs and a physical plant capable of handling flow that changes constantly in terms of volume and concentration of various solids. Fortunately, due to testing in the KWRP Pilot Plant (shown right), methods for increased efficiency within the system are proving successful and economical. Thus, the KWRP is ready and able to service increased numbers of industrial and residential users.

Physical components of the system include:


  • 3 bar screens

  • 3 rotary fine screens

  • 6 raw wastewater pumps (4 variable speed pumps)

  • 6 primary settling tanks - 68,850 cu ft. or 0.515 million gallons (MG) each

  • 9 aeration tanks - 272,000 cu ft. or 2.03 MG each

  • 4 blowers – 2 @ 2500 HP and 2 @ 1500 HP

  • 7 secondary clarifiers - 4 @ 1.85 MG each and 3 @ 1.32 MG each

  • 5 screw pumps for secondary effluent

  • 10 tertiary sand filters - 1173 cu ft. or 8770 gals each

  • many other pumps, both on-site and remote

  • automated control system

Solids Handling

  • 4 Belt Filter Presses

  • 1 Pasteurization Unit

  • 3 Biosolids Storage Bunkers (40,000 cubic feet each)

Pilot Plant

  • 2 equalization tanks

  • 2 aeration tanks

  • 2 secondary clarifiers

  • 3 tertiary sand filters

  • 2 secondary sludge gravity thickeners

  • plus laboratory equipment including an Arthur® Respirometer

KWRP uses powdered activated carbon in its process (PAC) - a modification of the activated sludge process that few plants use. The carbon modification allows the plant to treat strong industrial discharges without harming the microorganisms. The carbon protects the bugs from strong toxins by adsorbing them and helps dissolved chemicals settle. Microscopic examination of flow in the aeration tank indicates whether or not the bugs are healthy and active. Appropriate populations of free-swimming and stalk ciliates, rotifers and flagellates indicate a well-run process. A balanced growth of residential and industrial users provides ideal conditions for maximum productivity in the plant.

The KWRP currently operates at 47% hydraulic capacity.