Performance of a lab-scale bio-electrochemical assisted septic tank for the anaerobic treatment of black water

Carlos Zamalloa, Jan B A Arends, Nico Boon, Willy Verstraete

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

Septic tanks are used for the removal of organic particulates in wastewaters by physical accumulation instead of through the biological production of biogas. Improved biogas production in septic tanks is crucial to increase the potential of this system for both energy generation and organic matter removal. In this study, the effect on the biogas production and biogas quality of coupling a 20L lab-scale septic tank with a microbial electrolysis cell (MEC) was investigated and compared with a standard septic tank. Both reactors were operated at a volumetric organic loading rate of 0.5gCOD/Ld and a hydraulic retention time between 20 and 40 days using black water as an input under mesophilic conditions for a period of 3 months. The MEC-septic tank was operated at an applied voltage of 2.0±0.1V and the current experienced ranged from 40mA (0.9A/m2 projected electrode area) to 180mA (5A/m2 projected electrode area). The COD removal was of the order of 85% and the concentration of residual COD was not different between both reactors. Yet, the total phosphorous in the output was on average 39% lower in the MEC-septic tank. Moreover, the biogas production rate in the MEC-septic tank was a factor of 5 higher than in the control reactor and the H2S concentration in the biogas was a factor of 2.5 lower. The extra electricity supplied to the MEC-septic tank was recovered as extra biogas produced. Overall, it appears that the combination of MEC and a septic tank offers perspectives in terms of lower discharge of phosphorus and H2S, nutrient recuperation and a more reliable supply of biogas.

Original languageEnglish (US)
Pages (from-to)573-580
Number of pages8
JournalNew Biotechnology
Volume30
Issue number5
DOIs
StatePublished - Jun 25 2013

Bibliographical note

Funding Information:
Carlos Zamalloa is supported by the Institute for the Promotion of Innovation by Science and Technology-Strategic Basic Research (IWT-SBO) (Sunlight Project–Lipid-based, high value products and renewable energy from microalgae. Grant No. 80031 ) and by Ghent University (Grant No. 179I16D9W ). Jan B. A. Arends is supported by the European Community's Seventh Framework Programme FP7/2007-2013 (Grant No. 226532). This work is part of the Ghent University Multidisciplinary Research Partnership (MRP) – Biotechnology for a sustainable economy (Grant No. 01MRA510W ). The authors would like to thank Joachim Desloover, Jo De Vrieze and Karen De Roy for crucially reading the manuscript. The authors would like to specially thank Robin Declerck and Geert Favyts for their valuable technical assistance.

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