For case 1, all of the MSW was treated as mixed waste and Mechanical and Biological Treatment
(MBT) was chosen as the appropriate disposal technology. The conceptual design was discussed in the
previous work [8]. This paper presents the conceptual design and mass balance for case 2, according to
which the MSW can be separated with a separation efficiency of 25%.
Based on the current situation of MSW collection, only 2.5 tons per day of separated MSW were
collected and transferred to the disposal site belonging to the LAO. The conceptual design was
preliminarily conducted for 2.5 tons per day of MSW. If 25% of the organic waste and 25% of recycled
waste can be separated from all of the waste, the recycled waste can be sold at the recycling center, while
the organic waste can be treated as wet fraction and the remaining treated with the dry-combustible waste
as dry fraction. It was assumed that the hazardous waste was completely sorted out.
Considering the selection criterion mentioned in section 3.2, composting was the appropriate
technology for wet fraction (organic waste) disposal since it is widely used and reliable, with no difficulty
in operation. Based on viewpoint of economics, this technology requires low investment and operational
costs. Additionally, it can be operated in the community households.
Regarding the remainder from the separation process, which was referred to as the dry fraction,
incineration was selected as the promising and ultimate technology to treat the dry waste since it can
effectively reduce the volume of the mixed MSW, which has high flexibility for a non-homogeneous
composition. This incineration technology has been commercially used on both small and large scales in
many countries. However, this technology requires energy, normally from fossil fuel, for the combustion
process in order to maintain the desired operating temperature; consequently, there are high operation
costs. Hence, it is suggested that gasification technology be used in combination with incineration
technology to produce producer gas, which can further be supplied in the incineration system as substitute
fuel for fossil fuel. The conceptual design of the overall process for the MSW disposal technology,
focusing on the incineration technology for dry waste, is illustrated in Fig. 2.