Heat potential, generation, recovery and utilization from composting : A review

Fan, Shiyang; Li, Anran; Heijne, Annemiek ter; Buisman, Cees J.N.; Chen, Wei Shan


Composting is an effective process for treating organic solid waste (OSW). There is a growing interest in recovering and reusing heat from composting, in the context of climate change and fossil fuel depletion. Several literature reviews have been conducted to address the composting process; however, several engineering aspects, including heat estimation, recovery, and utilization, are inadequately addressed in current reviews. To fill this knowledge gap, we bring together the current knowledge on the heat from composting and provide a discussion on the methods for calculating the heat potential of OSW, estimating the amount of heat production and recovering the generated heat. Moreover, we summarize the utilization of generated heat and point out the challenges and the outlook for future research. The results show that the heating value of different OSW can be calculated by ultimate analysis, proximate analysis, or composition analysis. Moreover, different methods have been used for heat production estimation: the degradation method can adequately describe the composting process, O2 method is simpler to implement, and heat balance method is only valid at large scale reactors. Different types of reactors use different techniques for heat recovery: water jacket method is suitable for small-scale reactors, while tube buried-in pile method and percolation water method are especially suitable for lignocellulosic biomass composting. Heat exchanger in the head space method and low-temperature heat recovery technologies are mainly used for commercial reactors. The heat recovered from composting is potentially suitable for building applications such as hot water service, flooring heating and wall heating.