Water & Wastewater Asia Jan/Feb 2018

WATER & WASTEWATER ASIA January / February 2018 OPINION / 45 Food and water waste management It is a fact that everybody needs to eat. But food waste can be produced during meal preparation – kitchen waste – as well as after a meal, known as table waste. Dr Augustine Quek points out three ways in which food waste directly impacts water efficiency and use, as well as the importance of food waste management. Dr Augustine Quek W hile food waste is unavoidable in any society, its quantity can definitely be r e d u c e d a n d recycled. According to the National Environment Agency (NEA) in Singapore, nearly 680 thousand tonnes of food waste is currently being disposed of, making up some 22.3 per cent of total waste disposed. Thus, food waste, with a low rate of recycling of only 14 per cent, has high potential for improvement in its management. Consisting of more than 70 per cent of water, food waste is a formof putrescible waste, highly degradable and capable of decomposing quickly, attracting all kinds of pests that range from flies to rats. However, it is this same high percentage of water that implies that major benefits can be realised – and problems avoided – if food waste can be separated from the main waste stream, and its high water content, taken advantage of. Incinerating food waste All municipal solid wastes in Singapore, including food waste, are sent to incineration plants for mass burning to reduce its volume. Unfortunately, the high water content found in food waste hardly favours the incineration process, and most of the energy involved in burning food waste is absorbed by the water, reducing the efficiency of the incineration process. This, in tur n, hinders the production of energy, as all incineration plants in Singapore are waste-to-energy plants. In addition, the water that is boiled away in the incineration process is not captured for future use. Therefore, removing food waste from the incineration solid waste stream for alternative treatments is vital if both energy and water efficiency are to be achieved.