Recent Advances in Composting of Organic and Hazardous Waste: A Road Map to Safer Environment

Abstract

With the rapid development of economy and agriculture, continues to be the fast increase of organic and hazardous wastes such as animal manure, sewage sludge, green waste, antibiotics residue, municipal solid waste, and agricultural waste. These wastes contain lots of organic matter and nutrients, and also contain various kinds of toxic materials or elements (e.g., heavy metals, pathogens, antibiotics and antibiotics gens). The improper disposal of these wastes would result in environmental pollution and potential risk of human health. Composting technology is a kind of biological waste treatments, which has been widely accepted as an alternative method to recycle the organic matter and produce a stable and sanitary soil fertilizer or amendment. Furthermore, many researchers have elucidated the major factors such as temperature, pH, C/N ratio, moisture content, and particle size that are relevant in the monitoring of the composting process. However, the traditional composting still has some drawbacks such as nitrogen loss, leachate generation, odor problem, greenhouse gases (CH4 and N2O) emission, heavy metals (HMs) mobility, antibiotic residue, and antibiotic gens diffusion. During the composting process, 9.6–46% initial total nitrogen (N) is lost due to the volatilization of NH3, which not only decreases the compost quality, but also worsens the air pollution. Meanwhile, the greenhouse gases (CH4 and N2O) emission leads to environmental pollution. In addition, the high bioavailability of HMs in compost and the residual of antibiotic and antibiotic gens would also limit the development of composting technology and the land use of compost as well as cause hazard for ecosystem. In order to promote the composting progress and reduce the adverse effect during composting, many viable practical approaches have been applied adjusting the physicochemical parameters (e.g., moisture, C/N ratio, aeration rate and pH), using the different kinds of bulking agents, and adding the chemical agents, mineral additives, and microbial agent. This chapter discusses the benefit and challenge of composting of organic and hazardous waste. It will also discuss the current method to promote the compost quality and reduce the environmental risk.