INTEGRATED WASTE MANAGEMENT USING VERMITECHNOLOGY

Abstract

Modern lifestyle, rapid population growth, increasing per capita income, and diverse production and consumption patterns have increased the amount of solid and liquid wastes generation. There are issues associated with pollution and disposal. A typical SWMsystem in a developing country is usually characterized by various deficiencies including irregular collection services, open dumping and burning of the waste. Open dumping of garbage facilitates the breeding for disease vectors such as flies, mosquitoes, cockroaches, rats, and other pests. Nearly 80% of the water supplied is returned as municipal wastewater in the sewer system. Discharge of untreated or semi-treated sewage into water bodies has resulted in polluted rivers and other water bodies. It is very well understood that to prevent the water pollution proper management of both solid as well as liquid waste is required. The tried and tested methods of centralized treatment have proven ineffective in control of pollution. Adaptation of the technologies from the developed nations does not often provide the required solutions. The treatment plants provided becomes inadequate due to development of more and more residential and commercial complexes inside the cities increasing the waste quantity. The situation can be improved if these complexes have their own waste treatment and recycling systems. Same is true for the solid waste also. This calls for need of decentralized onsite treatment of all types of waste. Decentralized approach for waste treatment which employs a combination of onsite and/or cluster systems is gaining more attention. Vermitechnology is certainly an eco-friendly sustainable technique of waste management however; most available information/literature generally dealt with vermicomposting using monocultures of different earthworm species and rarely with polycultures. Fewer efforts were made for waste management using polycultures. Alternatively literatures have also confirmed the successful use of an innovative technology called vermifiltration for the waste treatment. Little literature is available suggesting vermifiltration of raw sewage through vermicast, sand, peat and gravel but limited literature is available on the treatment of both solid and liquid waste using vermitechnology. Therefore, efforts were made in the thesis to carry out vermicomposting of solid waste using polycultures as well as vermifiltration for the simultaneous treatment of both solid and liquid waste. A methodology has been developed for the treatment of both solid and liquid waste through vermitechnology. Simple, natural and low cost give an edge for such systems to be practical and realistic. iii In order to accomplish the objectives, studies were carried out on performance evaluation of vermicomposting reactors for solid waste and vermifilters for integrated waste treatment. The experimental work was carried out in two phases i.e. vermicomposting of solid waste and integrated waste treatment. Phase 1 dealt with vermicomposting of solid waste using single earthworm species (monoculture) and multiple earthworm species (polyculture). Phase 2 dealt with vermifiltration of solid and liquid waste for integrated waste treatment at different quantities of sewage application. . The results were statistically analyzed at 0.05 levels using one way analysis of variances (ANOVA) using Statistica software and SPSS package. Further, Tukey HSD test was used as a post-hoc analysis to compare the means. Result of the present study indicated that vermicomposting can be carried out in any type of waste with monoculture or polyculture. Adoption of this technology as a decentralized method of treatment minimizes the waste to be handled by the local body was well as recycling of the waste. The polyculture reactors produced rich compost with cattle manure, filter mud and vegetable waste amended with saw dust; however, in the case of sewage sludge polyculture and monoculture behaved similarly. In the case of the integrated waste treatment also polyculture proved to be better degrader and pathogen killer. Through control of flow rate the compost will be available without any liquid coming out of the system. The rate of sewage application and the number of vermifilters in series can be decided based on sewage objective e.g. if no sewage is to be reused the design should be such that no effluent comes out of the system. Local worms can be used effectively so as to minimize the effort and the cost. IV