Multifunctional approach to evaluate the efficiency of landfill leachate treatments

Abstract

Effluent treatment plants are designed to transform biodegradable material into nontoxic products, to capture suspended solids and nonsedimentable colloids, and to transform or remove nutrients and contaminants of different origin. The efficiency of the treatment depends, among other factors, on the physicochemical composition of the effluent to be purified, the operating characteristics of the processing plant, the environmental conditions and the taxonomic composition of the microorganisms living in the liquid to be treated. However, little is known about the different trophic functions of these organisms, their role in the degradation of organic matter, their nutrient requirements, and the relationship of these microorganisms with the physicochemical variables that ultimately determine the quality of the effluent output, and therefore, the efficiency of the treatment. In summary, this chapter will discuss: (1) The physicochemical characteristics of municipal landfill leachate during periods of high and low environmental temperature and rainfalls. (2) The taxonomic composition of the microorganisms (Protozoa, Chromista, and Metazoa) that fulfill key functions in the degradation of the organic matter in the aerobic lagoon of the treatment plant. (3) The ecotoxicity of landfill leachate before its discharge into the aquatic systems, using microcrustaceans and microalgae as test organisms, to evaluate the efficiency of the treatment performed. The results can be used to put management policies into effect, in order to reduce the impact of the pollution generated by the discharge of urban wastewater prior to its dumping into the aquatic systems, with the purpose of contributing to their ecosystem integrity.