The Choosing Of A Landfill Site Essay -- essays research papers

The Choosing of a Landfill SiteThere is currently much debate on the desirability of landfilling particular excesss, the practicability of alternatives such as waste minimisation or pre-treatment, the extent of waste pre-treatment required, and of the mostappropriate landfilling strategies for the final residues. This debate is likelyto stimulate significant developments in landfilling methods during the contiguousdecade. Current and proposed landfill techniques ar described in thisinformation sheet.Types of landfillLandfill techniques are dependent upon both the type of waste and the landfillmanagement strategy. A commonly used categorisation of landfills, tally towaste type only, is described below, together with a classification according tolandfill strategy.The EU drawing off Landfill Directive recognises three main types of landfillHazardous waste landfillMunicipal waste landfillInert waste landfillSimilar categories are used in many other parts of the world. In practice , thesecategories are not clear-cut. The Draft Directive recognises variants, such asmono-disposal - where only a single waste type (which may or may not be untamed) is deposited - and joint-disposal - where municipal and hazardouswastes may be co-deposited in order to gain benefit from municipal wastedecomposition processes. The landfilling of hazardous wastes is a contentiousissue and one on which there is not international consensus.Further complications arise from the difficulty of classifying wastes accurately,particularly the distinction between hazardous/non-hazardous and of ensuringthat inert wastes are genuinely inert. In practice, many wastes described asinert undergo degradation reactions similar to those of municipal solid waste(MSW), albeit at lower rates, with consequent environmental risks from gas andleachate.Alternatively, landfills can be categorised according to their managementstrategy. Four distinct strategies have evolved for the management of landfills(Hjelmar et al, 1995), their selection being dependent upon attitudes, economicfactors, and geographical location, as well as the nature of the wastes. Theyare Total containment Containment and collection of leachate Controlledcontaminant release and Unrestricted contaminant release.A) Total containmentAll movement of water into or out of the landfill is prevented. Th... ...eatment, and the most appropriate methods, are site-specific. Thetimescale required for active leachate management is dependent on the rate atwhich pollutants are flushed from the landfill. With conventional low-permeability top covers and containment strategies, it is likely that thetimescale will be several centuries, for wastes with a high pollution possible,such as MSW.There is currently a great deal of interest in shortening this effect by high-rate recirculation and partial treatment. As yet, these accelerated flushingtechniques have not been proven at full-scale. Until they are, or until wasteminimisation and p re-treatment reduce the pollution potential of the wastes thatare landfilled, the long time-scales for pollution control arising from currentlandfill techniques will remain.References1.Hjelmar O, Johannessen LM, Knox K & Ehrig HJ, Composition and management ofleachate from landfillsthe EU. To be presented at 5th International Landfill Symposium, Sardinia,October 1995return to text within 2.Dept of the Environment, A review of waterbalance methods and their application to landfill in the UK, UKDept of the Environment Report No. CWM 031/91.