Development and Preliminary Evaluation of a Commercial Duty Composting System

摘要

Garbage disposal has become an acute problem, not only because of its quantity, but also because of its kind. At present, most communities are dumping their garbage in open pits or at dumping areas designated by the respective cities and municipalities. This method including the indiscriminate burning of garbage is extremely unhealthy and unfriendly to the environment.rnComposting system is perceived an economical and favorable solution to the garbage problem. It converts organic waste materials into a nutrient-rich soil additive or humus through the action of bacteria and other micro-organisms under controlled aerobic conditions. The study was focused mainly on the development and preliminary evaluation of the composting machine using a fully enclosed vessel which includes power mixing and compost aeration. The fabricated machine was tested in terms of the following parameters which included carbon to nitrogen ratio, temperature, moisture content, pH level, length of decomposition, and percent yield.rnThe following were the significant findings of the study. The best compost proportion was 85:10:5 with an average C:N ratio of 35:1. Mature compost was achieved on the 27th day of decomposition. The final compost product had a temperature of about 42 ℃, percent moisture content (by weight) of 40, a pH value of about 7.0 and importantly, it did not posses foul odor. These values were good enough for a mature compost product. The total nitrogen, phosphorous, and potassium (as received basis) were 1.869, 0.356 and 0.446 percent, respectively. However, the results from oven-dry analysis (in percent) of total nitrogen content, phosphorous, and potassium were 2.323, 0.442, and 0.554, respectively. These nutrient contents are within the standard range provided by the World Health Organization. The percent yield obtained from the composting process was about 60% (by volume) considering an initial and final volume of 116 and 70 L, respectively.rnFurther improvement on the design of the composting system can be considered to enhance composting efficiency.