Abstract
Landfill leachate is an important pollution factor resulting from municipal landfill sites. Physical and chemical processes are the better option for pretreatment or full treatment of landfill leachate. This article presents a combination of pre-treatment method (coagulation and adsorption) for leachate collected from municipal solid waste open dumping site. Physico chemical characteristics of stabilized and fresh leachate were examined. Coagulation process was examined by using alum and ferric chloride. A low cost adsorbent, fly ash was used for adsorption studies. Coagulation studies were carried out for fresh and stabilized leachate. Adsorption studies have been conducted for alum pre-treated stabilized leachate. Effect of coagulant dose, adsorbent dose, pH and contact time were carried out. The effective optimum coagulant dosages were 0.6 g/L and 0.7 g/L for alum and ferric chloride respectively for stabilized leachate and incase of fresh leachate 0.8 g/L and 0.6 g/L for alum and ferric chloride respectively. For the alum pretreated stabilized leachate, the maximum COD removal is 28% using fly ash adsorbent with equilibrium time of 210 min and optimum dose of 6 g/L. Overall COD removal efficiency of 82% was obtained by coagulation using alum and adsorption using fly ash for stabilized leachate. The results obtained showed that combined coagulation and adsorption process can be used effectively for stabilized leachate treatment.
Highlights
Landfill leachate is an important pollution source originated in municipal landfill sites
Conventional landfill leachate treatments can be classified into three major groups: (a) leachate transfer to a municipal wastewater treatment plant where it is subject to combined treatment with domestic sewage, (b) biodegradation processes and (c) chemical and physical methods such as chemical oxidation, adsorption, chemical precipitation, coagulation/
The aim of this study was to study the feasibility of the combined coagulation and adsorption process as a pretreatment for COD removal in landfill leachate
Summary
Landfill leachate is an important pollution source originated in municipal landfill sites. Leachates may contain large amounts of organic matter, of which humic type constituents are an important group, as well as ammonia- nitrogen, heavy metals and chlorinated organic and inorganic salts [1]. The type of leachate depends on factors such as age and type of landfill, pH, and BOD5/COD ratio. Young leachates are generally low in pH (15,000 mg/L), biodegradable matters, BOD/COD ratio (0.5–1), and heavy metals (>2 mg/L); whereas old or Conventional landfill leachate treatments can be classified into three major groups: (a) leachate transfer to a municipal wastewater treatment plant where it is subject to combined treatment with domestic sewage, (b) biodegradation (aerobic and anaerobic) processes and (c) chemical and physical methods such as chemical oxidation, adsorption, chemical precipitation, coagulation/
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