Emission of volatile organic compounds from composting: A review on assessment, treatment and perspectives

Composting is a sustainable technology in treating organic pollutants and controlling odorous gas emissions from different organic solid waste, by reducing its size and volume. When the process parameters are handled efficiently, composting process is greatly effective than other waste treatment options in terms of operational costs, income generation out of compost, reduced air and water pollution. The successful composting operation does not count only the final product, but also the odorous gas emissions being released off to the atmosphere. Biofiltration is a relatively successful air treatment technology for polluted gases containing biodegradable compounds. By optimizing and focusing the operational parameters of biofiltration technology, 90% of treatment efficiency could be achieved with more economical advantage compared to other air treatment technologies. However, the complexity and the uncertainty measures in operating the system and understanding the process biodegradation mechanism is very crucial for the successful performance. Therefore, this review focusses and provides an assessment and treatment of different odorous gas emissions emitted during the composting processes. The recent advancements and treatment options for various volatile organic compounds (VOCs) and other odorous gas emissions during composting is updated. The advancements in bio-trickling filters, bioscrubber technology and membrane bioreactors treating VOCs has been focused. The use of different models in evaluating the process optimization and gas mitigation is also explained. Finally, the environmental impact of VOC compounds released into atmosphere from composting plants has been discussed.