Wednesday, June 20, 2012

MOON PLAINS SANITARY LANDFILL


In Sri Lanka, disposal of waste is a major environmental and social problem, which leads to several health problems like dengue in urban areas. As responsible government, Sri Lanka should have a proper way of disposing of waste. But in Sri Lanka, disposal of waste is mainly done by maintaining an open dump site, which will cause many environmental and health problems. Instead of open dumpsites, one proper way of deposing waste is maintaining a sanitary landfill. Moon Plains is one such sanitary landfill, which is started in 1996 by the Nuwara Eliya municipal council as a normal dumping site, and converted in to a sanitary landfill in 2003 with the help of JICA foundation. This land fill is located in a valley surrounded by a cultivated Eucalyptus forest, which is owned by the forest department, outside the Nuwara Eliya municipal council. And it is close to a water stream which provides water to a reservoir called Bomuraella which used for domestic and agricultural purposes by the people who are live around the reservoir. Initially this valley is used as an open dump site by the Municipal council without taking any environmental protection measures.
This valley which is 400m long and 30-40 meter deep is a part of 5.8ha catchment. And this valley consists of sandy clay soil and bed rock is a hard rock. Since Nuwara Eliya located in wet zone annual rain fall is around 2700mm therefore it gives rice to a seasonal stream which connects to the close by stream. When all the Municipal waste, Hospital waste and industrial waste is dump without any environmental protection measures it can easily contaminate that water stream and the reservoir causing serious environmental and health care problems to the society.

Nuwara Eliya municipal council used 2.0ha from the 5.8ha catchment as the dumpsite. Earlier this landfill did not contain any environmental protection methods like fence, gate, and other necessary facilities   that should be in a landfill like weigh bridge, leachate treatment method, buffer zone and water supply. To have a proper waste disposal open dumpsite should convert in to a sanitary landfill like in Moon Plains now. And the total open area which is 2.0ha is now has been converted to controlled sanitary landfill.
Moon Plain landfill has designed under a level 3 sanitary land fill which use semi aerobic landfill method. And it involves leachate control facility, leachate treatment facility. Drainage facility, a Gas venting facility as sanitary waste disposal facility and other required facilities, for education, for security and for Maintenance.

Leachate Collecting Facility
Leachate collecting facility is a pipe network that has installed underneath the landfill area which uses to collect the leachate. Pipe system used hard concrete pipes with relatively high diameter and with pores around the wall. This leachate collection facility will collect the leachate and guide it to the leachate treatment faculty.
Leachate Treatment Facility
Usually leachate coming out from the landfill contains significantly elevated concentrations of undesirable material derived from the material that it has passed through like organic acids, aldehydes, alcohols and simple sugars from municipal waste and heavy metals and halogenated organics from Industrial waste. Therefore leachate should treat before releasing it to the environment.
For that in Moon Plains there is a leachate treatment facility located at the down end of the valley. Leachate treatment facility contain combination system of coconut fiber a biological conductor for aerobic and anaerobic bacteria, Charcoal filter for remove suspended particles and heavy metals. And Wet land for filtration.
Gas Venting Facility
            Since this landfill use semi aerobic conditions gas venting facility is much needed in Moon Plain sanitary landfill. Gas venting facility help, aerobic bacteria to degenerate solid waste easily. Gas venting facility also includes pipe system that underlying the landfill which is end up with a perforated oil barrel filled with rubble stones. This gas vent will release CH4 (methane) and CO2 (carbon dioxide) to the environment without accumulating inside the landfill. By measuring the gas composition it is possible to predict the age of the landfill and the current status of the decomposition such like aerobic decomposition or anaerobic decomposition stage
Disposal pit for infectious waste
            Disposing of Medical waste or the infectious waste should be done separately with care minimize the contaminations. Therefore in Moon Plains, Hospital waste is dispose in to separate pit located away from the dumping site, which would not contaminate ground water or any other wastes.
Storm water Drainage
            Moon Plains sanitary landfill consists of two types of drainage systems. First one is Rip rap type along the waste filling slope and second one is Earth drain type along the access road to intercept all runoff from the out side from the access road. Storm water drainage system is designed to drain excess rain and ground water from the dumping site.
Tire wash pit
            Tire wash pit is located away from the dumping site in the access road. This help tractor to wash their wheels, after dumping the waste to dumping site. From this it is possible to avoid contaminating the road with waste.
Other than these facilities as sanitary waste disposal facilities, there are some other required facilities that has been fulfilled by the Nuwara Eliya municipal council, which are, two Access roads are constructed using asphalt paved for long term use, and using gravel for short term use. Gate for control the entry of vehicles. Movable fence to for prevent waste scattered to outside of the site during landfill operations. And a fixed type fence to control the entry to the site.
            As Educational facilities to illustrate how landfill operations are carried out in a sanitary landfill for students. And there is control room and a garage for bulldozer as the administration facility to administrate the work of the dumpsite.
            For proper sanitary landfill it should be monitored frequently and should control its activities as required. Monitoring and control of the landfill is do under the supervision of the monitoring committee which is chaired by the Chairman of the health committee fallowed by a municipal council member elected from the ward near the landfill site, member from a municipal council staff in Health Department, a member from municipal council staff in Works Department, A member from Central Environment Authority staff, member from the staff in local environmental NGO rand a representatives of neighborhoods. Monitoring is done frequently in early stages or the first six months, it is monitored every month and after first six month land fill is monitored after every three month this was done with the permission of the monitoring committee, permission is issued after six month from the starting date. For this purpose there is monitoring well located in the landfill. And monitoring is done according to a check list which is executed by the monitoring committee.
Problems associated with the Moon  Plains  sanitary landfill
            This land fill is classified as a level 3 sanitary landfill even though this is classified to a level three sanitary landfill there are some major problems with it, one is the discontinuous of the bed rock where bed rock plays a major role in preventing the contamination of ground water and since there is underground spring located in the site. Because of not doing a complete geological survey, authorities was not able to avoid the contamination of the underground spring hence Bomuraella reservoir unless use of a cement mortar, but they are fail to use cement mortar for entire area which cause leachate to penetrate through cracks. Second deficiency of the landfill is that they release the leachate without continuous analysis for BOD5 and COD levels which should be in the range of 30ppm and 250ppm respectively. And leachate collecting facility is good place for mosquito breeding and may lead to other health problems like Dengue epidemic. Third deficiency is that there is a lack of infrastructure facilities such as electricity, water and telephone facilities, which make administrating processors, are more difficult. By avoiding and completing those deficiencies Moon Plains sanitary landfill can improve more to achieve maximum use of the invested money and the time on it. 
References
1.      Asanga Manamperi, L.C. Jayawardhana, Ajith de Alwis, Sumith Pilapitiya; Usefulness of best fill expert system: a case study of three landfill sites in Sri Lanka,
2.      NA, Leachate,”Landfill leachate treatment expert website” ,Web 2012/ 5/6.