Influence of sludge age on the performance of MFC treating winery wastewater

• Power generation increases by decreasing the SRT.
• SRT control helps in the selection of electrogenic microorganisms.
• SRT did not influence on organic matter removal in biological treatment.
• Decreasing the SRT, Coulombic efficiency can be increased from 3.4% to almost 42.2%.
• Maximum power density of 890 mW m−2 can be achieved with MFC with SRT 1.2 d.

The objective of this paper was to determine the influence of sludge age on microbial fuel cell (MFC) performance for generating electricity and removing organic matter from winery wastewater. Six Solid Retention Times (SRT) were used: 1.2, 1.4, 1.8, 2.3, 3.5 and 7.0 d. Results demonstrate that the electricity generation increases by decreasing the SRT, selecting electrogenic microorganisms, once the specific organic loading rate (SOLR) increased and the competition for substrate was reduced. Decreasing the SRT, coulombic efficiency can be increased from 3.4% to almost 42.2% and maximum power density from 58 to 890 mW m−2. However the SRT did not influence on organic matter removal in biological treatment, because only a small part of COD was removed oscillating around 600 mg L−1 d−1and it was very similar at all SRT studied.