Effect of Thermal Pre-Treatments Method on Sludge Degradation Process Prior Usage in Membrane-Less Microbial Fuel Cell for Electricity Generation

Abstract

Abstract Microbial Fuel Cell (MFC) is gaining high interest by researcher around the globe as this is a promising renewable technology that has capability in producing electrical energy. In this study, the effect of the thermal pretreatment method (60, 80, 100, 120 and 140°C) on dewatered sludge (DS) as substrate for electrogenic bacteria (EB) in ML-MFC was optimized using one-factor-at-a-time (OFAT) method. The treated sludge then was used in ML-MFC by exposing them to the constant incubation temperature (35°C) with constant parameter of pH (6), initial moisture content (30 % vol/wt) and electrodes distance (3 cm) for 7 days incubation period. The performance of ML-MFC was relied on generation of soluble chemical oxygen demand (SCOD), power generation and EB biomass. Results shows the thermal pretreatment at 80°C was the optimum condition as the DS degradation rate (increment 78 %) when DS was treated for 4 h time treatment prior used in the ML-MFC. The degradation of DS was further degraded in ML-MFC via bio-catalysis process (51 % of SCOD produced compared initial DS inserted in MFCs ∼ 66 % SCOD removal). It was important to have a high DS degradation as the EB in ML-MFC would obtain more ‘food’ to growth thus increased the voltage (239 mV) and power density (98.34 mW/m 2 ) generation. In comparison, the control ML-MFC recorded low performance of DS degradation rate (21 %), voltage (24 mV) and power density 0.88 mW/m 2 . Thus, by combining the pretreatment method of dewatered sludge prior used in ML-MFC it could improve the performance and expanding the application of ML-MFC as future renewable technology for sustainability of power sources. The EB strains was Bacillus subtilis sp .

Key findings

• ▸Thermal pretreatment at 80°C resulted in a 78% increase in degradation rate of dewatered sludge.
• ▸The degradation of dewatered sludge was further enhanced in the membrane-less microbial fuel cell (ML-MFC) via bio-catalysis process.
• ▸The optimal thermal pretreatment time was found to be 4 hours.

Keywords

Identifiers

DOI

10.1088/1755-1315/765/1/012092

Journal

IOP Conference Series: Earth and Environmental Science

Year

2021