Used water + food waste + bacteria = energy for Singapore
SINGAPORE - The Republic can soon look to food waste and used water as energy sources. When food waste and sludge from used water react with bacteria, it converts the organic materials found in them into biogas, which can then be used to generate electricity.
A new demonstration plant housed within national water agency PUB's Ulu Pandan Water Reclamation Plant will be the first in Singapore to make use of this reaction to generate electricity, when it is completed in September 2015. The plant's launch was announced by PUB and technology company Anaergia during the second day of the inaugural Singapore International Water Week Technology and Innovation Summit on Wednesday. The plant will use a process patented by Anaergia, which makes use of anaerobic digestion, a biological process that breaks down organic materials without oxygen, to produce biogas. The collaboration between PUB and Anaergia is the result of an agreement signed during the Singapore International Water Week in 2014, where both had agreed to explore potential research and technological collaborations, particularly in the waste-to-energy domain.
It will be a test-bed to see if similar processes can be implemented at the future Tuas Water Reclamation Plant and the National Environment Agency's (NEA) Integrated Waste Management Facility, which is co-located with the Tuas water plant, PUB said in a statement.
As part of the Ulu Pandan project, used water sludge from the water reclamation plant will be mixed with food waste collected from the Clementi district and treated in the demonstration plant, called a co-digestion facility. "This new combined treatment of used water sludge and food waste has the potential to produce more biogas due to the higher calorific value in food waste," PUB explained. The plant can treat up to 40 tonnes of combined food waste and used water sludge. In March, the Ministry for the Environment and Water Resources, which NEA falls under, had announced that the NEA will be conducting a district level pilot in Clementi for the collection of food waste from various premises - such as educational institutions, hospitals and camps - for the demonstration plant. Clementi was chosen as it is near the Ulu Pandan Water Reclamation Plant.
About 788,600 tonnes of food were thrown away in 2014, slightly less than the 796,000 tonnes in 2013 but still much more than the 606,100 tonnes in 2009. And only 13 per cent of 2014's waste was recycled, even though food now accounts for about 10 per cent of all waste in Singapore. Said PUB's chief technology officer Harry Seah: "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, using only as much energy as the treatment process itself generates."