Study on composting of solid waste

Abstract

Composting is emerging to be a popular municipal waste management alternative both in developed and developing countries. In many cases it needs lower equipment and operation costs .It can divert a significant portion of organic waste from municipal collection services and from tinal disposal site, and therefore ,enhances both economic and environmental sustainability of waste management system. It is observed from the characterization of solid waste of Gazipur, the percentage of organic waste is more than 80 %. This organic waste can be effectively recycled by composting. The rate of generation of solid waste of the study areas at Gazipur is in the range of 0.233 to 0.39 kg/capita/day. This is slightly lower than that of Dhaka city. It is observed that per capita waste generation rate increases with the per capita income generation. Food habit and purchasing capacity of people influence the rising trend. The various controlling parameters of composting are observed during the digestion processes. The composting temperature of this experimental investigation was in the mesophilic and thermophilic range which is very helpful to destroy the pathogenic bacteria. It was observed from the first experimental setup, a portion of organic waste placed in the middle of the drum was not properly composted. Therefore an attempt was taken to modifY the barrel. The change in volume during composting after modification of barrel was observed and found that by placing perforated PVC pipe in the middle of the barrel, the rate of volume reduction becomes quicker. Chemical a•nalysis of compost samples indicate that the presence of vanous nutrients is almost same as that of compost sample of international market .Microbial analysis of ready compost sample indicates that no pathogenic bacteria are found in the compost as the elevated temperature during composting destruct the pathogens. Finally the financial involvement both in composting plant and in the barrel type composting processes is evaluated and found the economic feasibility of them. In the context of Bangladesh, the controlling parameters of composting are not available. So the information can be effectively used for designing a composting plant.