Understanding the causes of toxicity in treated landfill leachate through whole eefluent testing

Landfill leachate is collected and treated before discharge to protect the environment from a potential toxic cocktail of substances. In the U.K. biological treatment is the favourite technology for rendering landfill leachate safe due its simple design, effective handling of varying chemical loads and relatively low operating costs. Biological treatment is effective at reducing the concentrations of ammoniacal-nitrogen and the biological oxygen demand (BOD) to acceptable levels for discharge. Even though the ammoniacal-nitrogen and BOD levels have been reduced there still remains a considerable quantity of refractory organic chemicals and inorganic ions. Heavy metals tend be present in very low concentrations. A view has developed that these effluents potentially pose a risk to the aquatic environment due to the presence of these compounds. Cont/d.