Spatially informed multi-objective decision-making tool for retrofitting municipal wastewater treatment plants

Area of Science:

• Environmental Engineering
• Waste Management
• Sustainable Energy

Background:

• Wastewater treatment plants (WWTPs) are transitioning to resource recovery facilities by utilizing waste streams.
• Food waste (FW) regulations create opportunities for co-digestion and advanced energy recovery at WWTPs.

Purpose of the Study:

• Develop a spatially informed decision-making tool for WWTP retrofitting.
• Optimize retrofit configurations for economic and environmental objectives in New York State (NYS).

Main Methods:

• Modeled WWTP retrofit configurations considering FW co-digestion, Effluent Thermal Energy Recovery (ETER), and biosolids upcycling (HTL, HTC).
• Optimized strategies based on Net Present Value (NPV) and greenhouse gas (GHG) reduction.
• Incorporated environmental justice considerations for site prioritization.

Main Results:

• FW co-digestion is consistently optimal for economic and environmental goals.
• ETER for heating/cooling is cost-effective above 2.2 MGD; HTL is cost-effective above 60 MGD.
• Co-digestion, ETER (heating/cooling), and P2G are effective for GHG reduction; HTL offers greater environmental benefits than HTC.

Conclusions:

• A holistic decision-making model identifies optimal WWTP retrofits and statewide priorities.
• The model integrates economic, environmental, and social factors for comprehensive resource recovery.
• Four WWTPs are identified as high-priority candidates for retrofitting.