Producing High Value Carbon Products from Municipal Solids Generated from CEPT

Authors:

  • Wendell Khunjar, Ron Latimer - Hazen and Sawyer

A key element of low energy nutrient removal technologies like mainstream deammonification is the reliance on carbon diversion strategies, like chemically enhanced primary clarification (CEPT), to help control heterotrophic and autotrophic metabolism in mixed liquor. Solids generated from CEPT are typically anaerobic stabilized, resulting in the generation of biomethane, which can be captured and utilized as an energy source.

While energy recovery from biomethane can provide immediate benefits to many utilities, there are other valuable carbon products (e.g., volatile fatty acids (VFA), polyhydroxyalkanoate (PHA)) that have higher revenue potential than that associated with biomethane energy recovery. Therefore there is the opportunity to demonstrate that coupling carbon diversion with low energy nutrient removal can facilitate high value resource recovery.

To this end, we document the recovery of high value carbon products such as volatile fatty acids (VFA) and polyhydroxyalkanoates (PHA) from CEPT generated municipal sludge augmented with high strength organic waste – food waste (FW). Specific objectives were to: a) maximize the VFA production from co-fermentation of municipal solids with FW, b) maximize the PHA production from the VFA rich fermentation effluent, c) Perform an engineering assessment of implementing carbon recovery platform at full-scale WRRFs.

For more information, please contact the author at wkhunjar@hazenandsawyer.com.

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Horizons Fall 2017 (pdf)

Horizons showcases significant water, wastewater, reuse, and stormwater projects and innovations that help our clients to achieve their goals, and can help you achieve yours. Articles are written by top engineers and process group leaders, demonstrating and explaining the beneficial application of a variety of technologies and tools.

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