Method for the determination of completion of composting.

Composting may be defined as the biologic degradation of organic material, which contains a variety of readily decomposable compounds, into a relatively stable product or mass. A product or mass is produced which does not decompose or produce offensive odors as readily as the original material. Thus the chief aim of composting is to produce a relatively stable organic material approximately like that of a soil which has a carbon to nitrogen ratio of roughly 10: 1. Such material with a low carbon content, when added to the soil, prevents competition for nitrogen between growing plants and microorganisms. When a substance with a high carbon content is added to the soil, the bacterial population increases enormously taking out the soil nitrogen which otherwise would be available to the plants. Other important considerations for composting of organic materials are the reduction of bulk, ease of handling and storage, and prevention of offensive odors and accumulation of flies or other public health hazards. There is voluminous literature on composting dealing with the efforts and recommended procedures ranging in complexity from those of the individual home gardener to those of large scale processes. An excellent review of the literature on composting was published in Technical Bulletin No. 2 (1950b) which contained 610 references with numerous summaries. In their Technical Bulletin No. 1 (1950a) there is a complete review of commercial composting processes as employed abroad, particularly in Europe, and in the United States. The traditional method of composting is to place organic debris in a pile in a suitable area and allow the material to decompose. Periodically, the pile is turned and composting is allowed to continue. By this method, it takes from several months to a year to obtain a composted product. The commercial processes (Sanitary Engineering Research Project, 1950a) in Europe, such as the Verdier, Beccari, and Indore methods, attempt to speed up the process but still require about 20 to 90 days. In these processes, there is little or no control of environmental conditions. The Dano process, which is mechanized,