An evaluation of the capability of nanomodified vermiculite to in situ ammonium removal from landfill leachate

For the first time, the ammonium sorption from a municipal solid waste landfill leachate into the natural and nanomodified vermiculite mineral (NMV) were examined. NMV is a novel material developed to further improve the excellent ammonium absorption capacity of vermiculite. It can be prepared by heat treatment of natural raw vermiculite. In this study both laboratory and pilot experiments were performed. Municipal solid waste landfill leachates are a complex mixture of water and impurities with the high potential of environmental risk. When leachates were treated with NMV, the ammonium content in the leachates decreased drastically. The rate of ammonium sorption was particularly dependent on nanomodification, but also on time, temperature and grain size of the vermiculite used, and on the ammonium concentration in the leachate. According to the laboratory tests the ammonium decrease from the leachate was highest (64%) at room temperature (24 °C) using a small grain size (0.075–0.125 mm) fraction of NMV. Agitation is necessary in order to obtain highest possible ammonium ion reduction from leachate. In a pilot test 88% reduction relative to the initial concentration was obtained. The results show that NMV is an effective method for removing nitrogen from landfill leachate. Mathematical modeling was used to study the kinetics of the sorption process and the pilot test unit.