ABSTRACT
The general need for sustainability of modern urban systems includes a requirement for improvement in energy and resource recovery at wastewater treatment plants (WWTPs). This has led to a greater emphasis being placed on enhancing the efficiency of anaerobic digestion producing methane-rich gas (‘biogas’). A proposal for sludge disintegration has been incorporated recently into the process scheme of a WWTP to improve the hydrolysis phase of sludge digestion. Disintegration of waste activated sludge (WAS) prior to digestion is a common practice. The operational conditions and expected gains have been described by numerous authors (Müller et al. 1998, Müller 2000, Ødegaard 2004, Bougrier et al. 2005, Boehler & Siegrist 2006, Zabranska et al. 2006, Nickel & Neis 2007). Topics addressed by these authors have included:
• Increased net biogas production and thus better energy characteristics of the sludge handling system;
• Possible use of the organic matter obtained from a disintegrated WAS as a source of easily biodegradable carbon for denitrification processes;
• Minimisation of the sludge bulking effect in WWTPs.
