The Township of Delhi operates a conventional wastewater treatment plant designed to treat 4 to 5 mgd. The facility currently treats an average of 2.5 mgd of wastewater. Waste solids generated in the plant are combined with third-party organic wastes in a co-digestion process. The resultant biogas is used to heat the digesters and generate green electricity using microturbines. This provides additional revenue to Delhi through tipping fees and green energy generation.
Delhi faced multiple challenges with the facility’s operation, including issues with correctly receiving third-party waste streams, the inability to heat the digesters in the winter, and low power generation from the microturbines.
Delhi hired RETTEW to help identify solutions to these challenges. RETTEW developed the following plan to address their needs:
- A reconfiguration of the system to operate two thermophilic reactors to enhance energy recovery
- New mixers for the anaerobic digesters to increase the digestion rate
- A new biogas scrubbing system and combined heat and power system to increase green electricity generation and allow for heating the digesters in the winter.
These upgrades will save the Township more than $0.3 million per year when implemented.