title: Laboratory-scale ultrasound pre-treated digestion of sludge: Heat and energy balance.
abstract: The objective of this work was to maximize the digestibility of biological sludge to elucidate the feasibility of a new sludge management strategy to recover good quality sludge for agricultural use. The combined effects of organic loading rates (from 0.7 to 2.8g VS L(-1)d(-1)) and the degree of disintegration by anaerobic digestion of sonicated activated sludge were discussed, and the thermal and energetic balances were evaluated. Despite low sonication inputs, sludge digestion performance improved in terms of solids degradation and biogas production depending on the soluble organic load. The biogas production by sonicated sludge was higher (up to 30%) with respect to the control. Filterability improved during digestion of sonicated sludge at medium OLR due to a significant abatement of the fines. Thermal balances indicated that sonication may be a proper system to guarantee self-sustaining WAS mesophilic digestion. Nevertheless, thickening is a pre-requisite to achieve a positive energy balance.
authors.affiliation: Water Research Institute, CNR, Area di Ricerca RM1-Montelibretti, Via Salaria km 29.300, 00015 Monterotondo (Roma), Italy. braguglia@irsa.cnr.it
authors.forename: C M
authors.initials: CM
authors.lastname: Braguglia
authors.forename: A
authors.initials: A
authors.lastname: Gianico
authors.forename: G
authors.initials: G
authors.lastname: Mininni
mesh_terms: D001421:Bacteria, Anaerobic / Q000378:metabolism; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D005374:Filtration; D006358:Hot Temperature; D012722:Sewage / Q000737:chemistry*; D013010:Sonication / Q000379:methods*; D018505:Waste Management / Q000379:methods*
chemical_list: D012722:Sewage