Bio-conversion of organic wastes for their recycling in agriculture: an overview of perspectives and prospects

Largely accessible organic wastes can be turned into valuable compost product for raising crops organically on one hand, and get them disposed off safely at the other end. Straight use of organic wastes has tribulations like transportation and handling, wider C:N ratio, high application rates, nutrient overloading, weed seeds, pathogens, and metal toxicities. Composting bestows a tactic for coping high volumes of organic wastes in environmentally sound and desirable manners. Composted materials are remarkably regarded for their ability to improve soil health and plant growth, and suppress pathogens and plant diseases. Currently several composting systems have become available; ranging from a crude and slow windrows method, to the most speedy and computer monitored in-vessel system. Scientific investigations of this biological cum chemical process have reached to molecular level. Value addition of compost through beneficial microorganisms, mineral materials and fertilisers is also being considered. The nature and composition of materials put into composting is imperative for its quality rationale. On the whole, principles and processes governing composting are not so straightforward that ordinary enterprises could develop efficient composting facilities for the treatment of organic wastes. In this scenario, accessibility of comprehensive information to the scientific community as well as environmental protection agencies is imperative. This review article brings together the current information necessary for effective composting of organic wastes from different origins with diversified characteristics under various situations. It also covers the schematic description of well known composting systems, and various factors controlling the process.