Toward bioenergy recovery from waste activated sludge: improving bio-hydrogen production and sludge reduction by pretreatment coupled with anaerobic digestion–microbial electrolysis cells

Abstract

aIn this study, a novel technology named pretreatment coupled with anaerobic digestion-microbial electrolysis cells (AD-MECs) for waste activated sludge (WAS) reduction and renewable bioenergy recovery has been investigated. The results showed that, compared with the control pretreatment, the three pretreatment methods used greatly enhanced the performance of the AD-MECs process, and efficient sludge reduction was achieved, especially in heat-alkaline pretreatment, 36.9% and 46.7% for total suspended solid (TSS) and volatile suspended solid (VSS) removal in 6 days. MECs fed with fermented WAS, displayed positive potential for bioenergy recovery, and the highest bio-hydrogen yield was 20.30 mg H 2 /g VSS. Kinetic models indicated that with initial concentrations of soluble organic matter increasing, the bio-hydrogen yields of MECs increased linearly (R 2 ¼ 0.8903-0.9742). The results above suggested that the novel technology proposed in this work showed attractive potential for renewable bioenergy recovery and sludge reduction.

Transformation and release of phosphorus from waste activated sludge upon combined acid/alkaline treatment

“…[3][4][5] Waste activated sludge (WAS) is greatly generated as the by-product of wastewater treatment plants. [6][7][8] It has been reported that the content of P in dried sludge is around 2% in the conventional activated sludge process and 4-10% in the enhanced biological phosphorus removal process. 9 Considering the high production amount and P content of WAS, it can be an alternative P resource.…”

What could the entire cornstover contribute to the enhancement of waste activated sludge acidification? Performance assessment and microbial community analysis

“…With the conventional disposal routes coming under pressure, more cost-effective and environmentally benign alternatives for WAS are needed. Currently, due to its carbonaceous characteristics (organics possess 90–95% in dry weight), WAS is considered as a renewable and utilizable biomass resource and gained worldwide attention [3–5]. Cost-effective microbial conversion from WAS by anaerobic digestion to specific valuable products is an innovative and promising way to gain social and economic benefits.…”