A review of current practices and the feasibility of anaerobic digestion of biochar infused abattoir effluent

Anaerobic digestion (AD) of abattoir effluents offers a sustainable method for treating high-strength wastewater, simultaneously generating biogas and organic fertilisers. However, inhibitors such as ammonia, long-chain fatty acids, and volatile fatty acids often disrupt process stability and limit biogas production. Biochar, a carbon-dense byproduct of biomass pyrolysis, has proven to be an efficacious additive in addressing these issues by adsorbing inhibitory substances, regulating pH, enhancing microbe adhesion, and fostering direct interspecies electron transfer. This paper consolidates contemporary insights on the AD of abattoir effluent, the processes of biochar’s influence in AD systems, and the effects of feedstock type, pyrolysis parameters, and reactor design on system performance. The review emphasises the potential of biochar as an addition to the AD in abattoir effluents, which are noted for their elevated protein and fat content. We analyse technological, economic, and environmental factors; identify research deficiencies concerning standardisation, long-term impacts, and scalable implementation; and suggest future pathways to enhance biochar-assisted AD in abattoir wastewater. The review highlights biochar’s contributions to improving biogas production, stabilising microbial populations, and promoting circular economic goals.