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Feedstock receiving, processing, and handling

Authors: Zhongtian Li, Christian Tasser

Anaerobic Co-digestion: Principles and Guidelines Toward More Efficient Systems

A new technical publication from the Water Environment Federation (WEF) is helping water professionals better understand and apply anaerobic co-digestion as a pathway toward sustainable resource recovery. Titled Anaerobic Co-digestion: Principles and Guidelines Toward More Efficient Systems, the book provides comprehensive guidance for designing and operating co-digestion systems at water resource recovery facilities (WRRFs).

Carollo is proud to have contributed to this effort. The chapter, “Feedstock Receiving, Processing, and Handling”, was co-authored by Carollo’s Zhongtian Li and Christian Tasser, and focuses on one of the critical and complex aspects of co-digestion: feedstock management.

The Role of Preprocessing in Co-Digestion Success

As Zhongtian and Christian explain, the shift toward diverting food waste and other organics from landfills to co-digestion facilities has created new opportunities for WRRFs to generate renewable energy while supporting broader sustainability goals. However, the success of these efforts hinges on how well the incoming waste, referred to as feedstock, is managed.

“Inconsistent composition, high levels of physical contaminants, and logistical complications make preprocessing not just helpful, but essential,” the authors write. These challenges are particularly pronounced in source-separated organics (SSO) and the organic fraction of municipal solid waste (OFMSW), which can contain a wide range of materials, including food scraps, packaging, metals, and even hazardous materials.

The chapter delves into how facilities can address these issues by implementing tailored preprocessing strategies that reduce contamination and prepare feedstocks for more efficient digestion. The authors also highlight regulatory considerations, such as the need for pathogen control and permits related to animal by-products as co-digestion feedstock.

Feedstock Variability: Bridging Technical Knowledge and Operational Strategy

Beyond technology, the chapter emphasizes the importance of understanding feedstock variability across different regions and waste streams, and how that affects equipment selection, system design, and day-to-day operations.

As Zhongtian and Christian note, “A practical and robust operation and maintenance plan is essential for scheduling equipment operation and maintenance to accommodate a plant-wide energy management plan for in-demand bioenergy generation at WRRFs.”

The chapter also points to a growing need for system-level assessments and techno-economic analyses to guide utilities through the planning. As more facilities look to adopt co-digestion, such tools will help decision makers evaluate the financial implications of various feedstock strategies.

Anaerobic Co-digestion is Available Now Through WEF

The insights provided by Carollo’s team are just one part of this comprehensive resource, which is designed for engineers, utility staff, researchers, and students working in the field of anaerobic digestion. Whether you’re already managing co-digestion systems or considering future adoption, Anaerobic Co-digestion: Principles and Guidelines Toward More Efficient Systems offers practical knowledge for building effective programs.

Order your copy today through WEF to explore the full publication and learn more about feedstock management, system design, and energy optimization in co-digestion.

Citations

Li, Zhongtian, and Christian Tasser. “Feedstock Receiving, Processing, and Handling.” In Anaerobic Co-digestion: Principles and Guidelines Toward More Efficient Systems, chapter 5, Water Environment Federation. Published 2025.