7 research outputs found

    COMPOST FROM MARKET GARBAGE AND THE FEASIBILITY OF REDUCING THE TIME REQUIRED USING AERATION AND LOCALLY ACCLI MATIZEC' MICROORGANISMS

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    Solid waste collection and disposal is a major problem faced by all local authorities in SriLanka.The bulk of the waste, about 83%, is organic materials from vegetable markets andhouseholds. The predominant organic matter in waste makes itself ideal for biological treatmentprocess of waste management. The process of composting can be used to convert the waste to astable "humus like" product commonly known as compost, which could be used as a soilconditioner. This study was conducted using market garbage as the major ingredient, whichcontain 70% -90% moisture content and it was mainly directed to use low cost technology Themain objective was to reduce the production time and improve the quality of compost producedwith the use of inoculums and aerationSix different types of treatments were carried out during the experimental period. The windrowmethod was used to prepare compost under indoor environmental conditions. Vegetable garbage,air-dried grass clippings, saw dust, cow dung and coir dust were used as the raw organicmaterials. The initial total weight of waste was 250Kg (by wet weight). The experimental unitwas 1.5m x 1.5m x 1m (length x width x height). Two percentages of stabilized compost (2.5%,5%) were used as the inoculums. Hollow triangular wooden frame was used to facilitate aerationand mixing was carried out once a week.During the composting process physical changes (temperature, bulk density, changes indistribution of particle sizes), chemical changes (pH, organic matter, conductivity, C/N ratio) andbiological changes (C02 evolution, number of total coliform, invertebrates, weed seed viability,germination test) were determined to evaluate the em ctiveness of composting process.The results showed that composting of market garbage using stabilized compost as seeding andaeration helped to produce good compost at the end of two months. The high temperature stagecaused the destruction of the pathogenic organisms (number of coliforms), viability of weedseeds and fly larvae. Weed seed (Ameranthes seeds) lost their viability when exposed to highertemperature (>60 DC) for about three days. The drop i_7lC/N ratio is rapid at the initial stages andslows down during maturation stage, whereas the temperature increased and then decreasedfaster. The decline in temperature and -e/N ratio are somewhat similar. In all cases, thecomposting occurred under alkaline conditions and finally it reached neutral values.The final weights were approximately half of their original weights and the volume shrieked to1/3 of their initial volume. The bioassay indicated the level of completeness of compostingprocess and T2, T3 and T4 showed 100% germination at the end of 2 months.When composting, high moisture, organic materials under tropical environmental conditions, itis necessary to add bulking material with frequent turning. When composting process is properlyoperated and managed final product can be obtained in 8 weeks.

    The performance of a deep primary waste stabilization pond

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    This thesis describes an investigation into the performance of a deep primary waste stabilization pond under warm climatic conditions. Wastewater treatment designers in developing countries are constantly faced with the problem of selecting a system that is both efficient and economic. The main objective to this study was to determine safe loading rate and retention time in a pond deeper than the ponds ·normally used in warm climates. A secondary objective was to study the effect of using a deep pond in conjunction with a secondary shallow pond. A pilot-scale pond of 3.6m depth as primary pond and oi1 drum of 1991 capacity as secondary shallow pond were used under field conditions for the experimental study. The performance was evaluated by measuring influent and effluent BOD, COD and TC along with the measurements of DO, temperature, and pH profiles. Experimental results have shown that the high loaded deep pond is effective in the removal of bacteria and organic matter. A linear regression equation has been obtained for BOD and COD of raw domestic wastewater in order to predict BOD from COD measurements. The straight line regression equations have also been obtained to predict BOD and COD areal removal rates, covering ranges of 575 to .1406kg BOD/ha.d and 1137 to 2912kg COD/ha.d. Average climatological factors from records of a 25 year period were analysed and the permissible areal organic loading computed. From this analysis and the experimental results obtained, it was concluded that the maximum areal loading should be limited to 640kg BOD/ha.d (or about 1300 kg COD/ha.d) with a minimum hydraulic retention time of 11 days. Experimental study also revealed that the combination of a deep pond followed by .a secondary pond can produce a high quality effluent in terms of soluble organics and bacterial numbers. An empirical equation to predict BOD removal efficiency when volumetric ·organic loading is known was developed by analysing the experimental results and data collected from several publications. Using this equation, a chart to select suitable pond depths for different loading rates has also been developed. Beneficial and adverse effects of tropical climates on pond performance are identified and discussed. The areas which require further study and development are also identified. And recommendations made f6r future investigations

    The study of the environmental aspects of waste dumping in the city of Kandy

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    Inadequate collection and disposal of solid waste poses serious health risks to the population and leads to environmental degradation in many cities of Sri Lanka. Many local authorities do 110thave adequate funds and resources to manage the solid \\ asic generated within their local bodies

    Compost from market garbage using locally acclimatized organisms.

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    Nearly 80% of Sri Lankan garbage is biodegradable organic material. Today organic wastes are increasingly being converted into compost. Therefore it is necessary to look into the possibilities of improving compost quality and reducing the time taken for producing stable compost. This study was conducted using market garbage as the major ingredient of the composting process. The objective of this study is to reduce the production time of compost with the use of inoculants and aeration. Vegetable garbage, air-dried grass clippings, saw dust, cow dung & coir dust were used as the raw organic materials. The windrow method was used to prepare compost under indoor environmental conditions. A hollow triangular wooden frame was used in the pile to facilitate aeration. Mature compost was used as the inoculant to accelerate the composting process. The initial total weight of garbage was 250 Kg and after two months became 125 Kg. During the composting period compost pile was mixed once a week and the samples were tested in the laboratory. Physical & chemical changes of composting process were studied to evaluate the increasing efficiency due to inoculation & aeration. The periodic changes of temperature, pH, percentage of organic matter, carbon dioxide production rate, bulk density, weed seed germination were monitored during the composting process. The C/N ratio was measured to evaluate the degree of maturity of the compost. After two months of composting process, presence of pathogenic organisms (coliforms & ascaris egg mortality) and the maturity of the compost were determined. The study conducted up to now indicates that this process will give considerable information, which will help to reduce the environmental problem otherwise created by this market garbag

    Development of an expert system for better management of solid waste composting by pradeshiya sabhas in Sri Lanka

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    The increasing population and the ever-changing life style of the public have begun to add to the growing solid waste problem in Sri Lanka. As a solution, Local Authorities, NGOs, researchers and environmentalists have implemented several composting projects. Unfortunately, most of these projects are either abandoned or operating under poor conditions due to social, economic and technical problems encountered and none of options have solved the solid waste management problem itself. A key issue that is highlighted is the lack of qualified personnel (experts) to advise and assist Local Authorities to adopt the best solid waste management practices. Decision Support Systems and Expert Systems are favourable tools to overcome these problems. Therefore by capturing past mistakes, weak points and considering past experience, a user friendly Expert System called BESTCOMP was developed for better management of solid waste composting by Pradeshiya Sabhas in Sri Lanka. This research mainly focused on the behaviour of the physical, chemical and biological process in composting. The model is geared towards decision making as well as providing required expertise to solid waste composting hierarchy
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