Journal of Environmental Treatment Techniques  
2021, Volume 9, Issue 1, Pages: 211-217  
J. Environ. Treat. Tech.  
ISSN: 2309-1185  
Journal web link:  
Comparative Biodrying Performance of Municipal  
Solid Waste in the Reactor under Greenhouse and  
Non-greenhouse Conditions  
Katitep Ngamket, Komsilp Wangyao, Sirintornthep Towprayoon*  
The Joint Graduate School of Energy and Environment (JGSEE), King Mongkut’s University of Technology Thonburi, Center of Excellence on Energy  
Technology and Environment (CEE), PERDO, Ministry of Higher Education, Science, Research and Innovation, Bangkok  
Received: 01/09/2020  
Accepted: 05/11/2020  
Published: 20/03/2021  
The high moisture content of municipal solid waste yields a lower energy content of solid fuel that affects the thermal conversion  
efficiency. Biodrying is an alternative drying method using bio-heat generated by microbial metabolism to reduce the moisture content of  
municipal solid waste. This research was conducted in three pilot-scale biodrying reactors, two under greenhouse conditions compared with  
one conventional non-greenhouse condition. Two bunkers with greenhouse cladding were connected with aerators, and airflow rates were  
set at 0.4 and 0.6 m /(kgwaste·day), respectively. Meanwhile, a passive aeration method was applied to the non-greenhouse bunker. This study  
aims to investigate the effect of the greenhouse condition on the biodrying process and assess the performance of the drying process through  
different operating conditions. The result shows that the greenhouse mainly affects the air temperature rise in the reactor. The aeration rate  
is positively correlated with weight reduction (r = 0.93). At 0.6 m /(kgwaste·day) airflow rate, the treatment can reach a moisture content less  
than 30% on average within ten days, while at 0.4 m /(kgwaste·day) airflow rate, it takes 15 days to reduce the moisture content to less than  
0%. Biodrying under the greenhouse condition with active aeration potentially achieves desirable moisture content reduction and heating  
value increase more efficiently than the common biodrying. However, the airflow rate is a crucial factor in determining the suitable drying  
time in biodrying under the greenhouse condition.  
Keywords: Biodrying, Greenhouse, Municipal Solid Waste, Refuse Derived-Fuel, Solar Radiation  
There are many available drying methods for MSW, such as  
thermal drying and biodrying. The benefit of thermal drying is the  
shorter drying period (2.64±1.44 h) [2]. Meanwhile, the drying  
time of biodrying is about 16±7 days [2]. Nonetheless, thermal  
drying could have higher maintenance and operation costs for  
large-scale drying applications. Biodrying is an alternative drying  
method that uses metabolic energy from biodegradation for water  
evaporation in MSW or wastewater sludge.  
Aeration is a critical concern for heat generation from aerobic  
decomposition. The various