Comparison of enhanced anaerobic digestion processes in terms of methane production and final sludge hygienization

Sewage sludge processing is a key issue in wastewater treatment plants due to the inefficacy of conventional treatments to produce high quality sludge to be safely used in agriculture. Under this framework, the performances of several enhanced stabilization processes, namely ultrasound-pretreated Mesophilic Anaerobic Digestion (US-MAD), thermophilic anaerobic digestion (TAD), thermal pretreated TAD (TH-TAD) and ultrasound-pretreated inverse Temperature Phased Anaerobic Digestion (iTPAD) have been investigated. The enhanced anaerobic processes resulted in higher specific biogas production and higher destruction of E.coli and Somatic coliphages with respect to conventional MAD process, thus confirming the feasibility of these innovative processes in full-scale implementation perspectives.