Hybrid Bioenergy Recovery Framework from Intensive Aquaculture Systems

¹ Animal Science and Fisheries Management Unit, College of Agriculture, Engineering and Science, Bowen University, Iwo, Nigeria.
² Department of Electrical and Electronic Engineering Science, University of Johannesburg, South Africa.

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Intensive aquaculture systems generate nutrient-rich residues, including uneaten feed, faecal solids, pond sludge, and processing by-products, which can degrade receiving waters if poorly managed. Electricity-dependent farm operations, such as pumping, aeration, water treatment, and cold-chain management, are constrained in African contexts by unreliable power supply and high backup fuel costs. This study proposes a conceptual hybrid bioenergy recovery framework integrating anaerobic digestion (AD), microbial fuel cells (MFCs), and thermochemical conversion to support decentralised electrification within aquaculture-based production. The framework applies systems-engineering logic, mass and energy balance reasoning, and peer-reviewed evidence on the characteristics of aquaculture sludge and its conversion pathways. Wet residues are prioritised for AD, residual soluble organics are routed to MFC polishing where appropriate, and dewatered solids are assigned to pyrolysis or gasification. The results indicate that AD is the primary stabilisation and energy-recovery pathway through biogas production, MFCs are best applied as an effluent polishing step with incremental electricity recovery, and thermochemical conversion can extend solids valorisation through syngas, heat, and biochar production when drying requirements are met. The framework aligns with hybrid bioenergy recovery with circular bioeconomy objectives by prioritising waste minimisation, resource recovery, and local energy resilience for sustainable electrified aquaculture.