Case Studies

    City Reduces Disposal Costs by Replacing Belt Filter Presses with CS26-4 Dewatering Centrifuges

    Kzoo 3 CS26-4

    Location: City of Kalamazoo Water Reclamation Plant  |  Kalamazoo, Michigan
    Plant Size: 25 MGD
    Installation: 2021 (3) CS26-4 Decanter Centrifuges

    The Problem: In 2008, the utility moved to 100% landfilling sludge, taking advantage of a relatively low disposal cost: $17.5/wet ton. From 2008 to the present, the plant has faced a steady rise in disposal costs, on average 13.0% a year, to $33/wet ton in 2015, $64/wet ton in 2021, and in 2023 it is $158 per ton, among the highest in the region. However, the problem will continue to accelerate as 2024 disposal prices are planned to hit $158, $163 in 2025, and $171 in 2026. Cake dryness requirements (%TS) have also tightened. Maximizing the dryness of the dewatered cake and reduction of disposal volume became the top priority for the Dewatering Facility Upgrade in Kalamazoo.

    Kzoo Rising Disoposal Costs

    By 2026, when the disposal cost per ton is projected to be $171, landfill disposal costs will have experiences a 977% increase in costs in less than 20 years.

    The Results: Three Centrisys CS26-4 units were installed in 2021 and successfully started up in 2022 (Figure 2 below). The project design includes the necessary infrastructure to support the current installation along with the possibility of an additional fourth Centrisys CS26-4 if needed. The upgrade resulted in the immediate improvement in sludge dewaterability: before the upgrade a 2-meter Andritz belt filter press was generating 16-17% cake; after the upgrade, the centrifuges now generate cake in the range of 21-24%, which translates to a savings in disposals cost of 20-30% or roughly $2M-$3M annually based on 2022 fees.


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