Leachates and natural organic matter. A review of their biotreatment using fungi

Abstract

Leachates have different concentrations of organic matter and levels of biodegradability, depending on the age of the landfill and they must be treated using appropriate techniques, such as fungal degradation, in order to protect the environment and water resources. Natural organic matter contains the same type of organic species as old and medium age leachates, but at lower concentrations. The present study compiles and assesses all the available literature on the biotreatment of these compounds, mainly humic acids, by fungi. It was found that the efficiency of the fungal biodegradation of these wastewaters depends on the characteristics and concentration of the organic matter in the leachate, the microorganisms selected and whether they were immobilized or not, the nutrients present in the medium and their concentrations, the experimentation time, the temperature and the pH. The influence of the mode of inoculation has only been studied in natural organic matter, but similar effects are expected in the treatment of the leachates. The interactions between these parameters are complex and the optimal conditions have to be determined by laboratory and pilot testing, employing multivariate statistical techniques and experimental design.

Keywords: Biodegradation; Enzyme; Fungi; Humic acids; Leachates; Natural organic matter.