Leachate pre-treatment using non-woven geotextile filters

Geotextiles have been used as filters in geotechnical and geoenvironmental works for decades. They are cost-effective, easy to install and they reduce or avoid the need for exploitation and utilisation of natural granular filter materials. This study investigated the filtration function of geotextiles applied to the pre-treatment of leachate from a domestic waste landfill. Equipment was assembled where vertical panels of non-woven geotextiles were used as filters for raw leachate from a landfill. Five geotextiles with masses per unit area between 134 and 1800 g/m² were tested, and up to three filter panels were employed in the tests. Several chemical and biological parameters of the leachate were measured before and after filtration. A local sand filter was also tested for comparison. The results obtained showed that the geotextile filters reduced the values of leachate parameters, with a reduction of up to 42% in the case of chemical oxygen demand. The toxicity of the pre-treated leachate was also reduced to some extent, and the geotextile filter performed better than the sand filter tested in most of the cases. The filter arrangement employed may be particularly relevant for the pre-treatment of leachate from landfills of small- to medium-sized communities.