Pretreatment of nonbiodegradable landfill leachate by air stripping coupled with agitation as ammonia stripping and coag
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ORIGINAL PAPER
Pretreatment of nonbiodegradable landfill leachate by air stripping coupled with agitation as ammonia stripping and coagulation–flocculation processes Alkhafaji R. Abood • Jianguo Bao • Zaidun Naji Abudi • Dan Zheng • Chunlei Gao
Received: 18 May 2012 / Accepted: 20 December 2012 / Published online: 9 January 2013 Ó Springer-Verlag Berlin Heidelberg 2013
Abstract A combination process has developed as a pretreatment of non biodegradable leachate. The processes consist of air stripping coupled with agitation as a modified of ammonia stripping followed by coagulation–flocculation processes. The main aims of these processes are reducing a concentration of NH3-N and organic matter as well as enhancing the biodegradability of landfill leachate. Ammonia stripped by the airflow rate of 10 L min-1 at pH 11 for 3 h, while the agitation process applied to air stripping effluent for 2 h at the pH of 11.5 in 150 s-1 gradient velocity. NH3-N was removed at 96 % as removal ratio by the modified ammonia stripping in 5 h stripping time. Ferric sulfate, poly ferric sulfate and aluminum poly chloride was tested as a coagulant material in the coagulation process. Chemical oxygen demand (COD), suspended solids (SS), turbidity as well as the sludge ratios were discovered for each material operated under optimum condition of pH and dosage. The overall removal of NH3N, COD, biochemical oxygen demand, total organic carbon, and SS obtained by these processes were 96.5, 71.5, 56.5, 48.5, and 96.5 %, respectively, at the corresponding biodegradable ratio was modified from 0.20 to 0.31.
A. R. Abood J. Bao (&) D. Zheng C. Gao State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, People’s Republic of China e-mail: [email protected] A. R. Abood Thi Qar University, Nasiriyah, Iraq e-mail: [email protected] Z. N. Abudi Al-Mustansiryiah University, College of Engineering, Baghdad, Iraq
Keywords Landfill leachate Pretreatment Ammonia stripping Coagulation Flocculation
Introduction The sanitary landfill method has been widely accepted for waste treatment and disposal due to its lower cost of operation and maintenance when compared to other technologies. However, the major problem resulting from this method of waste management is the generation of large quantities of liquid leachate, which is a kind of wastewater with a high content of dissolved organic matter (DOM) (Calace et al. 2001). Leachate is a high-strength wastewater formed as a result of percolation of rainwater and moisture through waste in landfills (Hasar et al. 2009). For instance, it may contain a large amount of organic matter (biodegradable, but also refractory to biodegradation), where constituents of humic-type consist of an important group (Kang et al. 2002). The characteristics of landfill leachate depending on the type of MSW being dumped, the degree of solid waste stabilization, site hydrology, moisture content, seasonal weather variations, landfill age, and the stage of decomposition in
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