Resource recovery from landfill leachate by two-stage of direct contact membrane distillation

Abstract

Landfill leachate (LL) is a high organic matter and ammonia strength wastewater. The recovery of ammonia and water as by-products can be a path to a more sustainable management of LL. This study aims to evaluating the performance of a two-stage of Direct Contact Membrane Distillation for resource recovery from LL. In the first stage, the hot LL flows through the shell side of the polypropylene hollow fiber membrane module while the sulfuric acid solution passes through the lumen side. Ammonia is recovered as ammonium sulfate. In the second stage, the hot effluent from the first stage flows through the hot channel of the poly(tetrafluoroethylene) flat sheet membrane module, while cooled distillate water flows through the other side in countercurrent. The water evaporates and cross the membrane from the hot to the cold channel where it condenses. The results revealed the ammonia recovery rate was 87.38 % in the first stage, then, for each 1 m3 of LL, 2.20 kg of ammonia could be recovered. The water recovered (flux of 11.7 kg m−2 h−1) showed high quality, due to the great membrane rejection rate of colour (99.99 %), turbidity (99.88 %), TOC (99.98 %), NH3 (99.85 %) and phosphorus (99.88 %).