Leachate: production and characterization

Abstract

Leachate production deals with the creation of contaminated liquid at the base of a landfill. It involves the elements of a water balance in which precipitation either runs off from the landfill or infiltrates. Some infiltration will evapotranspire, some may be stored within the landfill, and the balance becomes percolate and eventually leachate. Examples of the water balance method are presented and consideration is given to the sequence of landfill development and the effect that it has on leachate flow. Information is provided on the microbial decomposition of municipal solid waste and the conditions which influence decomposition rates. The impact of the microbial processes on leachate contaminant composition is examined. Leachate characterization requires that estimates be made of contaminant types and concentrations as a function of refuse age. Data describing contaminant production from various sources are examined. A procedure is presented to combine the water balance method and contaminant production curves to predict leachate flow and strength with respect to site age. A simpler alternative involving a set of tables showing expected contaminant types and ranges of concentrations as a function of refuse age is also provided.La production d'eaux de missellement entraine la formation de liquides contaminks a la base des sites d'enfouissement. Ce phCnomkne met en cause les elements du bilan hydrologique qui font en sorte que les prtcipitations slCcoulent du site d'enfouissement ou s'y infiltrent. Une certaine quantitk des eaux d'infiltration s'tlimine par tvapotranspiration, alors qu'une autre partie s'accumule dans le sol du site d'enfouissement; le reste s'infiltre par les interstices du sol pour atteindre la nappe phrkatique. Des exemples de la mCthode du bilan hydrologique sont prCsentCs et une attention particulikre est accordCe la sCquence de dCveloppement du site d'enfouissement et a son effet sur l'tcoulement des eaux de missellement. Des renseignements sont foumis sur la dCcomposition microbienne des dCchets solides et les conditions qui influent sur la vitesse de dCcomposition. L'impact du processus microbien sur la composition des matikres contaminantes des eaux de missellement est examint. La caractkrisation de ces eaux de ruissellement exige que des Cvaluations des types et des concentrations de contaminants soient faites, en fonction de l'ige des detritus. Des donntes dtcrivant la production de contaminants partir de diverses sources sont examinCes. Une proctdure permettant de combiner la mCthode du bilan hydrologique et les courbes de production des contaminants afin de prCdire 1'Ccoulement et la concentration des eaux de missellement en fonction de l'bge du site est prCsentCe. Un ensemble de tableaux montrant les types de contaminants prCvus et les Cchelles de concentration en fonction de l'ige des dttritus est Cgalement fourni.Mots clPs : site d'enfouissement, eaux de missellement, tcoulement, estimation, modkle.[Traduit par la revue]Can. J. Civ. Eng. 16.317-325 (1989)

Caracterização geofísica em aterro de resíduos sólidos para avaliação de condicionantes de instabilidade geotécnica

“…Dessa forma, o chorume proveniente de aterros recentes é caracterizado por altos níveis de ácidos orgânicos, amônia e sólidos totais dissolvidos, mas grande parte da massa biodegradada é fragmentada com o tempo, e a concentração desses parâmetros decresce no material livixiado de aterros antigos (Farquhar, 1989).…”

Introduction – A Review of Membrane Reactors

“…Improvements in landfill engineering are aimed at reducing leachate production, collection and treatment prior to discharge (Farquhar 1989). Nitrification is generally readily achievable, with >95% removal of ammonia reported through the exclusive application of biological techniques to the treatment of both young and old leachates (Ahn 1999, Welander 1998, Horan 1997.…”

Decomposição de resíduos sólidos domiciliares e variações na resistividade e cargabilidade

“…Entretanto, a quantidade de gás e material livixiado produzido pode ser afetada pela profundidade de disposição do material, condições climáticas regionais, variações do nível freático, Tabela 1 -Mudanças típicas nas concentrações de chorume de acordo com a idade do resíduo (Farquhar, 1989;Birks & Eyles, 1997) Sódio + Potássio 2000-4000 500-1500 100-500 < 100…”

“…Alcalinidade 10000-15000 1000-6000 500-2000 < 500 espessura do material de recobrimento e controle de entrada e saída de líquidos daárea (Farquhar, 1989).É esperado que nas partes rasas do material ocorra rápida decomposição aeróbica enquanto que no corpo de resíduos em profundidade ocorra somente a decomposição parcial sob condições anaeróbicas. Ao cruzar a base do aterro,íons metálicos em solução podem ser removidos por troca iônica, sorção ou precipitação direta no substrato, especialmente quando argiloso.…”