A new process for the combined treatment of municipal wastewaters and landfill leachates in coastal areas

Abstract

One of the most convenient methods for leachate control is to treat landfill leachates with domestic wastewaters. In this framework, a two-stage treatment system including anaerobic pre-treatment combined with a chemical post-treatment system such as ammonia stripping and/or Magnesium Ammonium Phosphate (MAP) precipitation can be comparable with a conventional secondary biological treatment. In this study, 2.5% and 2% of leachate by volume was mixed with domestic wastewater as the feed for the mesophilic Upflow Anaerobic Sludge Bed Reactor (UASBR). pH, feed strength and hydraulic retention time (HRT) were monitored for the evaluation of the performance of the anaerobic process. The HRT's varied from 0.76 to 0.52 d and 58% and 85% COD removal efficiencies were obtained at Organic Loading Rates (OLR) of 0.63 and 2 kg COD/m3.d respectively. The average biomass (VS) concentration in the reactor increased from 40 g/l to 50 g/l during the study. Effluents from the UASBR were further treated chemically either with lime for ammonia stripping or with MAP precipitation. MAP precipitation was applied both at the stoichiometric ratio (Mg:NH4:PO4 = 1:1:1) and above the stoichiometric ratio (Mg:NH4:PO4 = 1:1:1.3). Maximum NH4 removal of 66% was achieved at the pH of 9.3 at the stoichiometric ratio, whereas 86% NH4 removal was obtained at the pH of 9.3 above the stoichiometric ratio. Alternatively, ammonia stripping was applied either to the effluents directly taken from the anaerobic reactor or to the effluents to which MAP precipitation was applied stoichiometrically. Ammonia stripping was conducted for 24 h and 89% NH4 removal was observed at the end of 24 h. Consequently, this study indicates that anaerobic pre-treatment combined with chemical post-treatment (MAP) produced high quality of effluent comparable to the conventional biological treatment especially in terms of N and P levels.

Review on Landfill Leachate Treatments

“…Li et al [38,39] [76] and Altinbas et al [3] studied MAP precipitation after anaerobic pre-treatment of domestic wastewater and landfill leachate mixture. Maximum ammonia lowering was obtained as 66% at a pH of 9.3 at the stochiometric ratio whereas ammonia lowering reached to 86% at the same pH above the stochiometric ratio.…”

Human-virulent microsporidian spores in solid waste landfill leachate and sewage sludge, and effects of sanitization treatments on their inactivation

“…Land application of sewage sludge is a viable method of nutrient (i.e., nitrogen and phosphorus) soil fertilization; this has increased during recent years due to economic and environmental reasons (Straub et al 1993;Westrell et al 2004;Gale 2005). It has however, been shown that spreading sludge on agricultural land both facilitates the circulation of pathogens in the environment and also leads to the contamination of potable waters via surface runoff (Chauret et al 1999;Yangin et al 2002;Hutchison et al 2005) posing a threat to human and animal health. Disposal of sewage sludge in municipal landfill can result in the contamination of waste liquor with human pathogens (Sobsey 1978;Yangin et al 2002;Szostakowska et al 2004).…”

“…It has however, been shown that spreading sludge on agricultural land both facilitates the circulation of pathogens in the environment and also leads to the contamination of potable waters via surface runoff (Chauret et al 1999;Yangin et al 2002;Hutchison et al 2005) posing a threat to human and animal health. Disposal of sewage sludge in municipal landfill can result in the contamination of waste liquor with human pathogens (Sobsey 1978;Yangin et al 2002;Szostakowska et al 2004). Such pathogens usually occur in raw sewage sludge and sewage sludge end products in high concentration due to the fact that they precipitate during wastewater processing (Straub et al 1993;Yangin et al 2002;Westrell et al 2004).…”

“…Disposal of sewage sludge in municipal landfill can result in the contamination of waste liquor with human pathogens (Sobsey 1978;Yangin et al 2002;Szostakowska et al 2004). Such pathogens usually occur in raw sewage sludge and sewage sludge end products in high concentration due to the fact that they precipitate during wastewater processing (Straub et al 1993;Yangin et al 2002;Westrell et al 2004). Pathogens in sewage sludge present a health risk for waste-treatment operatives, farm, and refuse workers exposed to sludge and landfill leachates (Straub et al 1993;Yangin et al 2002;Westrell et al 2004;Hutchison et al 2005).…”

Post‐treatment of anaerobically treated medium‐age landfill leachate

“…Maximum COD and turbidity removals obtained were 25.7 and 36.4%, respectively. However, Yangin et al [37] and Ozturk et al [14] obtained about 50% COD removal with MAP precipitation of anaerobically treated leachate [24,37]. Kapdasli et al [38] stated that COD removal in MAP process is due to the adsorption of organics onto the surface of MAP crystals, so the differences in the COD removal efficiencies could be attributed to the different physical properties of crystals formed during MAP precipitation.…”