Solid waste landfill leachate treatment and utilization of reverse osmosis reject water

Summary

The leachate of solid water municipal landfills contains high concentrations of organic waste decomposition products and mineral salts. COD concentrations in organic substances can reach 5,000 mg/l; of ammonium ions – 2,500 mg/l; of total dissolved salts – 15,000 mg/l. In order to meet the current regulations on the discharges into the environment including fishery water bodies, the treatment of such wastes by two- or three-stage reverse osmosis is required. The performance of modern reverse osmosis membranes designed for demineralization of groundwater and sea water is low due to high salinity and COD levels in wastewater. Experimentally, the main dependences of the required reject water flow on the degree of ammonium ion removal were obtained. The use of nanofiltration membranes provides for reducing the reject water flow and operating costs. For the utilization of the reverse osmosis reject water, separating the waste flow into the following streams is proposed: with a high concentration of organic substances and with a high concentration of mineral salts, such as sodium and ammonium chlorides.

Key words

reverse osmosis , membrane selectivity , municipal solid waste landfill leachate , permeate yield increase , membrane performance decrease , membrane replacement expenditures