tailieunhanh - Hazardous Industrial Waste Treatment - Chapter 12 (end)

Các bãi chôn lấp chất thải sinh hoạt là một trong những phương pháp phổ biến nhất để xử lý chất thải. Trong những năm qua họ đã phát triển đáng kể do tăng trưởng nhu cầu bảo vệ môi trường. Ban đầu, các bãi chôn lấp hàng rào xa khu dân cư, nhưng bây giờ họ được đánh giá cao thiết kế cơ sở cho phép xử lý chất thải an toàn và hạn chế tác động môi trường. Các mối đe dọa lớn các bãi chôn lấp có liên quan đến nước rỉ rác thải ra môi trường | 12 Treatment of Landfill Leachate Michal Bodzek and Joanna Surmacz-Gorska Silesian University of Technology Gliwice Poland Yung-Tse Hung Cleveland State University Cleveland Ohio . INTRODUCTION Municipal waste landfills are one of the most popular methods for waste disposal. Over the years they have evolved significantly because of growing environmental protection demands. Initially landfills were fenced in far from residential areas but now they are highly engineered facilities that enable secure waste disposal and restrict environmental impact. The major threats of landfills are related to leachate discharge into the environment. A badly designed or managed landfill can be the source of groundwater and soil pollution because of seeped leachate. Leachate arises from rainwater percolating through the waste deposit and washing out solubilized and suspended organic compounds as well as inorganic salts. The quality and amount of washed-out organic compounds depend on disposed wastes and their decomposition phase. Since landfill wastes are subjected to mainly anaerobic biological processes their intermediate and final products are present in the leachate. Among them are substances especially harmful to the environment such as AOX adsorbable halogenated organics PCB polychlorinated biphenyls heavy metals and so on. High concentrations of ammonia nitrogen chlorides and sulfates also exist. Therefore many countries regulate leachate as hazardous industrial waste. However in practice raw leachate is often treated with wastewater in municipal wastewater treatment plants MWWTP without any additional processes. This method is recognized as subpar 1-3 because it can disturb wastewater treatment plant performance in several ways namely it can provoke the following nitrification difficulties Nitrites build-up or complete inhibition of both phases of nitrification Lack of organic carbon in sufficient amount for nitrites and nitrates reduction Heavy metals present in .