Anaerobic Co-Digestion of Tannery and Slaughterhouse Wastewater for Solids Reduction and Resource Recovery: Effect of Sulfate Concentration and Inoculum to Substrate Ratio

Ashton B. Mpofu, Victoria A. Kibangou, Walusungu M. Kaira, Oluwaseun O. Oyekola and Pamela J. Welz
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Ashton B. Mpofu: Department of Chemical Engineering, Bellville Campus, Cape Peninsula University of Technology, Symphony Way, Cape Town 7535, South Africa
Victoria A. Kibangou: Department of Chemical Engineering, Bellville Campus, Cape Peninsula University of Technology, Symphony Way, Cape Town 7535, South Africa
Walusungu M. Kaira: Department of Chemical Engineering, Bellville Campus, Cape Peninsula University of Technology, Symphony Way, Cape Town 7535, South Africa
Oluwaseun O. Oyekola: Department of Chemical Engineering, Bellville Campus, Cape Peninsula University of Technology, Symphony Way, Cape Town 7535, South Africa
Pamela J. Welz: Institute of Applied Microbial and Health Biotechnology Institute, Cape Peninsula University of Technology, Bellville Campus, Symphony Way, Cape Town 7535, South Africa

Energies, 2021, vol. 14, issue 9, 1-19

Abstract: Anaerobic digestion is considered unsuitable for the bioremediation of tannery effluent due to process inhibition, mainly due to high concentrations of sulfur species, and the accumulation of H 2 S and/or NH 3 . This study using the standardized biochemical methane potential protocol showed that efficient processing is possible with slaughterhouse wastewater, provided sufficient functional biomass is present at the start of the process and the SO 4 2 − concentration is below inhibition threshold. Methanogenic activity (K = 13.4–17.5 and µm = 0.15–0.27) and CH 4 yields were high when reactors were operated ISR ≥ 3 and/or lower SO 4 2 − ≤ 710 mg/L while high SO 4 2 − ≥ 1960 mg/L and ISR < 3.0 caused almost complete inhibition regardless of corresponding ISR and SO 4 2 − . The theoretical optimum operating conditions (922 mg/L SO 4 2 − , ISR = 3.72) are expected to generate 361 mL biogas/gVS, 235 mL CH 4 /gVS with reduction efficiencies of 27.5% VS, 27.4% TS, 75.1% TOC, 75.6% SO 4 2 − , and 41.1% COD. This implies that tannery sludge will be reduced by about 27% (dry mass) and SO 4 2 − by 76%, with a fraction of it recovered as S 0 . The models displayed a perfect fit to the cumulative CH 4 yields with high precision in the order Logistic > Cone > modified Gompertz > first order.

Keywords: anaerobic codigestion; tannery wastewater; slaughterhouse wastewater; inhibition; resource recovery; kinetics (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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