Biosolid Management Options in Cassava Starch Industries of Thailand: Present Practice and Future Possibilities

Abstract

Greenhouse gas (GHG) emissions from the existing biosolid management practices in cassava starch industries of Thailand have been evaluated and compared with other biosoild management options with a view to reduce GHG emissions and possible energy recovery. The study involved development and application of a spread-sheet based evaluation tool to estimate GHG emissions, benefits such as GHG offsets and possible energy recovery from four different cassava pulp waste management options viz.: (i biodrying followed by production of refuse derived fuel (RDF), (ii) composting, (iii) anaerobic digestion with energy recovery and (iv) landfilling with energy recovery. Parameters such as GHG emissions, benefits in terms of GHG mitigating potential and energy recovery ton -1 of cassava pulp waste were determined for each biosolid management option. Total baseline emissions from the existing cassava biosolid management practices were estimated as 4.2 kg CO 2 eq. ton -1 of cassava pulp waste. Among the four waste treatment alternatives, biodrying followed by RDF production scenario showed the highest GHG mitigating potential of 85.2 kg CO 2 eq. ton -1 cassava pulp. On the other hand, landfill option with biogas flaring resulted in highest net GHG emissions of 28.7 (kg CO 2 eq. ton -1 cassava pulp). Biodrying followed by RDF has the highest net heat energy gain (NEG) of 1 536 MJ · ton -1 of cassava pulp treated. However, for conversion of waste-to-energy, anaerobic digestion has the highest net energy ratio (NER) for heat as well as electricity recovery with high GHG mitigation potential. © 2015 A. Ghimire, R. Sen, A. P. Annachhatre. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of HK-ICONS 2014.

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