Acceleration of organic removal and electricity generation from dewatered oily sludge in a bioelectrochemical system by rhamnolipid addition.

Conversion of biomass energy of dewatered oily sludge to electricity is the rate-limiting process in bioelectrochemical system (BES). In this study, 2mgg-1 rhamnolipids were added to dewatered oily sludge, resulting in a significant enhancement in maximum power density from 3.84±0.37 to 8.63±0.81Wm-3, together with an increase in total organic carbon (TOC) and total petroleum hydrocarbon (TPH) removal from 24.52±4.30 to 36.15±2.79mgg-1 and 29.51±3.30 to 39.80±2.47mgg-1, respectively. Rhamnolipids can also enhance the solubilization and promote the hydrolysis of dewatered oily sludge with increases in SOCD from 14.93±2.44 to 18.40±0.08mgg-1 and VFAs from 1.02±0.07 to 1.39±0.12mgg-1. Furthermore, bacteria related to substrate degradation were predominant in dewatered oily sludge, and bacteria related to the sulfate/sulfide cycle were significantly enriched by rhamnolipid addition.