Singapore co-digests 40 tph food waste with sludge to yield more biogas

Singapore water utility PUB has started the nation’s first project to produce biogas through co-digesting used water sludge and food waste. In this project, used water sludge from the Ulu Pandan Water Reclamation Plant (WRP) will be mixed with food waste collected from the Clementi district and treated in a co-digestion demonstration facility. Due to the “higher calorific value in food waste”, this new combined treatment of used water sludge and food waste has the potential to produce more biogas, PUB said in a statement. The co-digestion plant can treat up to 40 tons of combined food waste and used water sludge. It will adopt the OmnivoreTM process patented by energy company Anaergia, which makes use of anaerobic digestion, a biological process that breaks down organic materials without requiring oxygen to produce biogas. As part of the project, the National Environment Agency (NEA) will be conducting a district level pilot in Clementi for the collection of source-segregated food waste from various premises – such as educational institutions, hospitals and camps – for co-digestion at the demonstration plant. The demonstration plant is currently under construction and will be completed by September 2015. If successful, the process could potentially be implemented at the future Tuas Water Reclamation Plant and NEA’s Integrated Waste Management Facility. This collaboration is a result of an MOU signed during the Singapore International Water Week (SIWW) in 2014, in which both Anaergia and PUB agreed to explore potential research and technological collaboration, particularly in the domain of waste to energy. Harry Seah, chief technology Officer, PUB, said: “This demonstration plant aims to validate the efficacy and cost-effectiveness of co-digestion implementation in Singapore. It will provide the opportunity for the water reclamation plants to generate more electricity for process usage. This could potentially allow the used water treatment plant to achieve energy self-sufficiency, which is using only as much energy as the treatment process itself generates.” Andrew Benedek, Anaergia’s chairman and chief executive Officer, said: “There is no better place than Singapore nor a better utility than PUB to work together with to demonstrate Anaergia’s ground-breaking technologies designed to make water reclamation plants energy neutral.” This project was supported with a co-funding grant from the Technology Pioneer Scheme, administered by the Singapore Economic Development Board on behalf of the Environment and Water Industry Programme Office. ### Read more Taking recycling lessons from Super Singapore Integrated thinking: solid waste management in Singapore