Integrated digestate management: Contaminant control, valorisation and circular pathways.

Area of Science:

• Environmental Science
• Agricultural Science
• Chemical Engineering

Background:

• Digestate management is crucial for environmental protection and sustainable agriculture.
• Challenges include compositional variability and persistent contaminants like heavy metals, pharmaceuticals, microplastics, and PFAS.
• Current research is fragmented, lacking a unified approach to risk, technology, and decision-making.

Purpose of the Study:

• To systematically review digestate characteristics, contaminants, and treatment technologies.
• To critically compare technologies based on nutrient recovery, contaminant control, and circular valorisation.
• To propose a decision framework for selecting appropriate digestate valorisation strategies.

Main Methods:

• Systematic literature review and synthesis of existing research.
• Critical comparison of conventional, advanced, and emerging treatment technologies.
• Development of a structured decision framework integrating techno-economic, environmental, and maturity aspects.

Main Results:

• Many current technologies redistribute contaminants into side streams rather than eliminating them.
• Integrated treatment trains combining separation, recovery, and destruction are needed.
• A decision framework is proposed to guide technology selection based on digestate composition and management goals.

Conclusions:

• An integrated approach is necessary for safe and circular digestate valorisation.
• The proposed framework supports tailored strategy selection considering techno-economic feasibility and environmental performance.
• Further research and policy development are needed to advance sustainable digestate management.