Sustainable energy and drinking water access have been seen as major challenges for rural households in Bangladesh despite of governmental and non-governmental organizations have been made extensive efforts. This study contemplates a universal approach towards tackling both of these issues via biogas based polygeneration integrated with membrane distillation employed at the village level. The specific technologies chosen for the key energy conversion steps are as follows: plug-flow digester (co-digestion and mesophilic condition); internal combustion engine; and air-gap membrane distillation. The proposed techno-economic results show that daily electricity demand can be met with such a system while simultaneously providing 0.4 m3cooking fuel and 2–3 L pure drinking water. Cost analysis illustrates that the approach is highly favorable compare to other available system. The payback time of such system is between 2 and 2.5 years.

In this study, membrane distillation integrated with district heating network has been investigated for applications in a bioethanol production plant. The specific application considered was recovery of ethanol from CO2 scrubber water, where the main objective of this study was to develop an air gap membrane distillation system that is driven by heat from district heating network, to offload the distillation column. Experiments on membrane distillation lab unit along with data from the industry were used to assess the technologic and economic feasibilities of this system. Comparisons were also made between the distillation columns and membrane distillation units in terms of heat demand and economic savings. Results of the study showed that MD can be a competitive technology for ethanol concentration depending on availability of low-grade heat like district heating or waste heat.