Study on Bin Composting Process: Application of Forced and Passive Aeration

Abstract

Composting is an age-old technique to manage solid waste. Composting with appropriate process of aeration reduces solid waste volume and the end product can be used us organic fertilizer and other beneficial purposes. Some times larger scale composting process is difficult due to big investment and other management problems. However. then: is an option that, the individuals can convert their kitchen and garden waste efficiently to compost using different bins. This study work was conducted to investigate the effect of forced and passive aeration on bin composting process. For this six runs of bin composting process is performed. For both forced and passive aeration composting specially designed 50 liters capacity plastic bins were used. Suitable organic waste was collected from student's hall of Khulna University of Engineering & Technology, KUET and saw dust from local sawmills and paper from offices of KUET. The individuals sold waste were mixed with selected proportions. Before and after experiments the physical parameter.<: like moisture content, volatile solids and fixed solid was performed. Temperature was measured regularly in bin composting process for forced and passive aeration. Degree and extent of degradation of waste mixture were identified through different composting process. Simple mass balance analysis was developed for two types of bin composting process. The analysis also helps lo characterize the compost. The compost released from every experiments of bin composting was used as feedstock of self-heating test. Some thermos flask was used for self-heating test. Temperature developed in the flask was measured manually using thermometer. The physical parameters were tested before and after all self-heating test runs, The available data from self-heating test are used to find out the biological stability of the compost The results shows that (i) Similar set of composting using similar initial waste mixture shows almost similar area under temperature curve, that is the area is almost same for forced and passively aerated composting. In first experiment (Exp-I) of this cype the areas are 8174 °h and 9541 °Ch for passively and forced aerated bin respectively. In another experiment (Exp-4) of this type the areas are 10584 °Ch and 10350 °Ch for passively and forced aerated bin respectively. (ii) Since the range of degradation and area under temperature curve for both process is almost same, therefore the passively aerated bin composting is suggested for batch purpose. It does not need external energy for aeration. In forced aerated bin composting 0.06 kw/h energy is needed for aeration for single aquarium aerator. (iii) Almost no leachate and offensive odor were detected during all bin composting experiments. This can be taken as effectiveness of the bin composting process. (iv) Mo~t of the mass balance shows the general trend of volatile solid reduction from beginning to end of the composting process. This creates a physical feeling of mass reduction in composting process.