SINGAPORE Anaerobic Digestate (AD)
Food waste conversion options in Singapore: Environmental impacts based on an LCA perspective
Hsien H. Khoo a,⁎, Teik Z. Lim b, Reginald B.H. Tan b
a Institute of Chemical and Engineering Sciences, 1 Pesek Road, Jurong Island, Singapore 627833, Singapore
b National University of Singapore, Department of Chemical & Biomolecular Engineering, 4 Engineering Drive 4, Singapore 117576, Singapore
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Conclusions:
Significant reduction of global warming impacts can be realized by implementing the food waste AD recycling process. This was achieved by both reduced energy requirements for the process itself and CO2 savings from the compost produced from the digestate material.
– Aerobic composting showed environmentally favorable results compared with the mass incineration of food waste. However, aerobic composting is less preferred compared to AD due mainly to CO2 and NH3 emissions, as well as, low amount of bio-compost produced.
– It was suggested, however, that further investigations is needed to test the value of N and P nutrients of the compost products from both methods. Additional studies are also required to examine aerobic composting on local foodwaste samples to test its potential to obtain higher output.
– Energy generation from the food waste AD recycling process was projected to be an impressive 78% for Recycling Phase I and 82% for Recycling Phase II, assuming that both recycling phases are operating at full capacity.
– The AD’s Recycling Phase II operating at full capacity alone will allow Singapore Green Plan’s 2012 aim to increase the recycling of food waste to 30% to be achieved; combined Phase I and II increases the recycling rate to about 47%; further increase in recycling rate is possible with a proposed aerobic composting plant.
– Small-scale composting can be recommended as a way to divert food waste away from incinerators, however, a more sustainable solution will be to expand the operating capacity of the AD recycling facility
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