Accelerators for Composting -By SUNITA GAIND

Composting is a cost effective and environment friendly way of waste recycling. Though an old technology but hastening the process of composting, improving nutrition and quality status of compost by blending composting substrates with microbial inoculants, organic nitrogen and phosphorus sources are some of the novel aspects of present day composting. Composting is a self-heating, aerobic, biological process of degradation and mineralization of organic matter. It depends on the growth and activity of mixed populations of indigenous microorganisms that bring about the thermophilic decomposition of organic residues under controlled conditions. During the composting process, complex substances present in organic residues are converted into simple and plant-available forms, pathogens and weed seeds are destroyed, and malodors are abated. As compost can be prepared from variety of substrates, their chemical composition affects the composting process. There are certain myths that composting does not need any microbial inoculants due to pre-existing diverse microbial flora in the decomposing substrates. However, one cannot assume that organic wastes and residues will contain the desired kinds of microorganisms to facilitate their conversion to a quality compost product. The introduction of specific microbial inoculants in the form of cellulolytic or lignolytic fungal consortium, accelerates the process of decomposition, thereby shortening the composting period. Inoculants can speed up the decomposition process by adding additional micro-organisms to the compost pile. Moreover, the quality of compost in terms of humus is also improved.

Accelerators for composting consists a unique blend of mesophilic or thermophilic molds or yeasts or bacterial cultures that drastically accelerates composting process of most organic waste materials and eliminates mal-odors during the composting process.

The selection of microbial strains is very important and depends upon the material to be composted. During composting, the degradation is brought about by a number of enzymes. No single culture possesses all the necessary hydrolytic enzymes in optimum level, therefore, mixed inoculum has always been found more effective in accelerating the composting of agro-wastes compared to single culture. However, the strains present in mixed culture should be compatible with each other and needs to be ascertained before application.

The microbial inoculum consisting of fungi of genus Aspergillus, Penicillium, Trichoderma, Phanerochaete and Pleurotus sajor caju, bacteria of genus Azotobacter, Bacillus, Cellulomonas, Chaetomium, Clostridium, Coprinus, Microbispora, Pseudomonas, Thermoactinomyces, and Trichurus, have widely been studied.

Inoculation with mesophillic fungi as Aspergillus awamori, A. niger, A. nidulans, Trichoderma reesei, T.viride, Phanerochaete chrysosporium can accelerate the decomposition of high silica paddy straw, wheat straw, chickpea stover, pearl millet stover and bagasse trash.

A consortium of lactic acid bacteria, photosynthetic bacteria, yeast and filamentous fungi of genus Phanerochaete can substantially reduce the composting period of paddy straw decomposition.

Similarly the use of specially developed bio-inoculum consisting of nitrogen fixers of genus Azotobacter and phosphate solubilizers of genus Pseudomonas and Bacillus accelerate the process of composting and improve the nitrogen and phosphorus status of finished compost. The end product is mature compost with C: N ratio < 15: 1. As compost is prepared from residues of plant and animal origin, it is rich in micro-nutrient commonly required for crop growth. The exothermic biological process during composting makes the end product free from harmful pathogens and troublesome weed seeds.

Things that need attention
• Microbial inoculants for composting are effective only under proper conditions.
• The raw organic materials to be composted must have an acceptable C : N ratio and moisture content to support microbiological activities.
• After the organic materials are mixed, simply add the microbial consortium of carefully selected cultures to your compost heap/pile for accelerated composting and boosting of overall quality of compost
• As the microbiological population and activities increase, temperature, and moisture levels of the composting biomass need to be monitored regularly. Maintain aerobic conditions by regular turning of the composting substrates.
• .Within 6 to 8 weeks, the raw organic materials is transformed into a friable and stable humus-like product.
• Treated compost will be fertile, rich and provide excellent benefits to plants of all types.
• By using quality compost, excessive chemical fertilizer usage can be avoided as well as environmental protection can be ensured.

About Author / Additional Info: