Treatment of waste activated sludge with thermal hydrolysis and mesophilic anaerobic digestion

Enhancement of waste activated sludge (WAS) anaerobic digestion by means of pre- and intermediate treatments. Technical and economic analysis at a full-scale WWTP

“…Traditional pre-treatments (mechanical, thermal, chemical or a combination of them) are intended to make 61 the biological substrates more usable for enzymatic attack through the disruption of cell walls 62 (Collivignarelli et al, 2015;Carrère et al, 2010;Teo, 2016). However, several authors demonstrated that 63 also Extracellular Polymeric Substances (EPSs) in sewage sludge is a factor for poor anaerobic digestion 64 (Shana et al, 2015;Williams et al, 2015). EPS is a part of sludge biochemical composition (carbohydrates 65 and proteins) and two types of EPSs are involved in WAS digestion.…”

“…71 Thus, EPS is an unavoidable by-product of the WAS digestion process. Therefore, a possible solution to deal 72 with EPS production during sludge digestion is to make use of intermediate hydrolysis processes (IHPs, Li et 73 al., 2013;Williams et al, 2015). 74…”