Release of Dark Colored Leachate from Mined Aged Municipal Solid Waste from Landfills

Abstract

The present study focuses on the release of dark colored leachate from soil-like material (SLM) reclaimed from aged municipal solid waste (MSW) at three dumps of India (located at Delhi, Hyderabad and Kadapa). If the material is to be used in filling low-lying areas or in embankments or subgrade, the leaching of colored liquid can cause coloration of the surrounding water bodies and ground water. Local soil was used as a base material for comparison of release of color. Mined soil-like material from MSW releases dark and objectionable color of leachate. The intensity of color of leachate from mined SLM is found to range between 380 and 400 Hazen, 460 and 480 Hazen and 900 and 1000 Hazen in the samples from Delhi, Kadapa and Hyderabad landfill, respectively. In contrast, the intensity of color in water released from local soil varies between 25 and 30 Hazen. The study concludes that small amount of mined SLM requires large quantity of water (70–100 times) for washing the material before the intensity of color reduces to acceptable level, thereby demonstrating the potential to significantly impact nearby ground water wells. Thermal treatment is observed to be reducing the color to acceptable level before reuse.