Management of the cross media impacts of municipal landfill sites: the Delphi technique

Abstract

Most of the existing solid waste disposal sites in Malaysia are practising either open dumping or controlled tipping because the technology of proper sanitary landfill practice is not totally implemented. The environmental conditions from these sites are thus expected to be bad especially in terms of the contamination of soil, air, surface and underground water, and also impacts on flora and fauna including human. The contamination associated with solid waste disposal sites involved three major environmental compartments or media, i.e. the atmosphere, water and soil. This 'Cross media' or 'Multimedia' impacts phenomenon has been recognised in various countries as being of potential importance and complicated. This study discusses on the development of simple evaluation systems by using the Delphi Approach, which emphasises on the development of weightage for different parameters selected in the evaluation procedures. Environmental conditions of all closed and active disposal sites in the study area from 9 different points of view (water quality, social, gas emissions, landuse, hydrology, geology, ecotoxicology, plant ecology and chemical constituents) were assessed, which has taken into consideration 59 selected parameters. The Landfill Pollution Index (LPI) was introduced and made into a software, which is more user friendly and requires minimum inputs from the user. The LPI incorporated with 4 other subindices, i.e. the Environmental Degradation Index (EDI) for water quality, gas emission, chemicals in surface water and chemicals in groundwater. The results of assessments indicated that most of the solid waste disposal sites in the study area showed relatively bad environmental conditions especially the operating or active site, i.e. Taman Beringin landfill site. Taman Beringin was the most polluted landfill with the LPI of 719.56, followed by Jinjang Utara (383.51), Paka 1 (197.66), Brickfields (128.90), Paka 2 (113.72), Sri Petaling (30.81) and Sungei Besi (17.87).