Professional Evaluation of Constructed Biodigesters for Slaughterhouse Waste Management in Kano Metropolitan Abattoir

This study conducts a professional technical and operational evaluation of biodigester systems installed at the Kano Metropolitan Abattoir in Kano State, North West Nigeria, for the treatment of slaughterhouse wastewater, blood, and solid organic waste. Abattoir waste streams are among the most oxygen-demanding and pathogen-rich industrial effluents, and their improper disposal into municipal drains and the Challawa River has been a persistent pollution problem in Kano. Two anaerobic biodigester units were installed at the abattoir under a public-private partnership arrangement, and their technical performance and operational management are assessed in this study. The evaluation methodology encompasses operational data review, influent and effluent sampling over a twelve-week period, energy output measurement from biogas generation, and assessment of digestate quality for agricultural application. Operational management practices including feedstock pre-treatment, retention time control, pH monitoring, and biogas utilisation are evaluated against design specifications and CSTR biodigester operational best practice. Results show that chemical oxygen demand removal efficiency averages 78 percent and pathogen reduction meets WHO biosolids Class B standards for the digestate. Biogas production yields an equivalent of 62 percent of the abattoir's generator fuel requirement, demonstrating significant cost offset potential. Operational management quality is the primary performance limitation, with inadequate staff training resulting in suboptimal hydraulic retention time maintenance. The study recommends a structured operator training programme and installation of automated feedstock flow measurement. Keywords: biodigester, slaughterhouse waste, anaerobic digestion, abattoir, Kano.