Operations and Maintenance Manager Mike Bourke says that a HotRot machine is being tested as part of the treatment process, turning into compost screenings and grit removed from the wastewater, instead of sending them to landfill.

The closed, in-vessel HotRot system is designed to deal with a wide range of organic waste, including all sewage solids, trade wastes and green-waste.

Using a process of computer-regulated agitation and aeration, the waste is converted into a safe and reliable soil conditioner or compost. The system contains any odours, protects groundwater through the elimination of leachate and creates a compost that is free of weeds and pathogens.

The system was developed by the Wool Research Institute of New Zealand (WRONZ) and is being marketed by R5 Solutions (NZ). The company takes its R5 name from the waste hierarchy (reduce, reuse, recycle, recover and residuals management).

“The Wasterwater Treatment Plant has purchased the HotRot system, and R5 Solutions will operate it for a year before they hand it over to us,” says Mr Bourke.

R5 Solutions general manager George Pottinger says that the company’s underlying philosophy is to provide waste minimisation systems that offer economic benefits while improving environmental management and sustainability.