Role of Composting in Environmental, Soil, and Plant Health Management

摘要

Regulations governing the concentrations of priority pollutants in the environment have had major impacts on the adoption of waste separation strategies and of composting as the preferred alternative process for treatment of solid wastes. Composting of commingled or mixed municipal solid wastes (MSW) has all but been abandoned because the compost produced cannot consistently meet the quality expectations of most users. In contrast, yard waste composting is practiced widely and food and restaurant waste composting are increasing rapidly. Composting of municipal, paper mill and of other industrial sludges also is increasing steadily, particularly where priority pollutants have been removed from these waste streams or where land application of the rawmaterial is problematic. The composting process also is used widely for bioremediation of soils contaminated with a variety of pollutants. Concerns over the release of odors, pathogens and of organic nutrients from animal manures into the environment have emphasized problems associated with utilization of untreated agricultural wastes. As a result, composting is becoming a mainstream agricultural practice. Innovative animal housing facilities and manure management systems now are emerging which producecomposts cost effectively, if all factors are considered. This development is beginning to have an impact on solid waste management on farms. High value markets have been developed for composts in horticultural products such as in mulches and potting mixes. The disease suppressive nature of composts is recognized more widely today. This development and the increased availability of high quality composts to the horticultural industries are facilitating the phase-out of methyl bromide. Biocontrol agent-fortified composts, which provide more predictable control than natural composts, promise to further increase this trend. Regulations and guidelines governing composting and compost quality standards now are under consideration by or in effect in several countries. In conclusion, solid waste management through composting has had major impacts on environmental, soil and plant health management. This chapter summarizes the most recent trends in this field.