Yangin C, Yilmaz S, Altinbas M, Ozturk I
Istanbul Technical University, Environmental Engineering Dept, Maslak, Turkey.
Water Sci Technol. 2002;46(8):111-8.
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.
渗滤液控制最便捷的方法之一是用生活污水来处理垃圾填埋场渗滤液。在此框架下，包括厌氧预处理与化学后处理系统（如氨汽提和/或磷酸铵镁（MAP）沉淀）相结合的两级处理系统，可与传统的二级生物处理相媲美。在本研究中，按体积计2.5%和2%的渗滤液与生活污水混合，作为中温上流式厌氧污泥床反应器（UASBR）的进料。监测pH值、进料强度和水力停留时间（HRT）以评估厌氧工艺的性能。HRT在0.76至0.52天之间变化，在有机负荷率（OLR）分别为0.63和2 kg COD/m³·d时，COD去除效率分别达到58%和85%。在研究过程中，反应器内平均生物量（VS）浓度从40 g/l增加到50 g/l。UASBR的出水进一步用石灰进行氨汽提化学处理或用MAP沉淀法处理。MAP沉淀法按化学计量比（Mg:NH4:PO4 = 1:1:1）及高于化学计量比（Mg:NH4:PO4 = 1:1:1.3）应用。在化学计量比下，pH值为9.3时，NH4最大去除率达到66%，而在高于化学计量比且pH值为9.3时，NH4去除率达到86%。或者，氨汽提应用于直接取自厌氧反应器的出水，或应用于按化学计量比进行MAP沉淀的出水。氨汽提进行24小时，24小时结束时观察到NH4去除率为89%。因此，本研究表明，厌氧预处理与化学后处理（MAP）相结合可产生与传统生物处理相当的高质量出水，特别是在氮和磷含量方面。
