Ziyang Lou, Youcai Zhao
The State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
J Hazard Mater. 2007 Aug 17;147(1-2):257-64. doi: 10.1016/j.jhazmat.2006.12.084. Epub 2007 Jan 13.
Fresh leachate and effluents samples were collected from the holding tank, anaerobic, anoxic, and aerobic lagoons at Shanghai Laogang Refuse Landfill, the largest landfill in China with a placement scale of 9000 t refuse per day. To characterize the difference in leachate along the treatment processes, especially the information about size distribution of colloids in those leachate, the organic matters were size-fractioned into suspended particles (SP, >1.2 microm), coarse colloids (CC, 1.2-0.45 microm), fine colloids (FC, 0.45 microm to 1 kDa MW, 1 Da=1/16 O atomic mass unit), and dissolved organic matters (DM, <1 kDa MW) using micro-filtration and ultra-filtration membranes in order. The parameters, such as COD (chemical oxygen demand), TOC (total organic carbon), TS (total solid), pH, TP (total phosphate), TN (total nitrogen), FS (fixed solid), NH4+, IC (inorganic carbon), TC (total carbon), color, turbidity and conductivity in the filtrates resulting from sequential filtration of leachate, were then determined, and quantitative relationships between these parameters and the membrane molecular sizes used were established. Typically, the total removal of COD, NH4+, conductivity and P were found to be 75%, 75%, 42% and 85%, respectively, after the biological treatment processes used at Laogang Refuse Landfill. Dissolved fractions were predominant in fresh leachate and in effluents from treatment processes in terms of TOC with a content of over 47%. The molecular weight (MW) percentage distribution in leachate varied as the leachate was treated in the biological treatment stages. The percentages of TOC of fine colloid fractions increased from 6% to 38% while those of dissolved fractions decreased from 78% to 47%. TN in leachate also predominated in the dissolved fraction, occupying over 58%, while those TP in leachate were combined with the SS and CC fractions. The ratios of ortho-phosphate/TP and NH4+/TN in leachate and effluents were over 50% and 80%, respectively.
新鲜渗滤液和出水样本取自上海老港垃圾填埋场的储存池、厌氧池、缺氧池和好氧池。上海老港垃圾填埋场是中国最大的垃圾填埋场，日垃圾处理规模为9000吨。为了表征渗滤液在处理过程中的差异，特别是这些渗滤液中胶体粒径分布的信息，通过依次使用微滤膜和超滤膜，将有机物按粒径分为悬浮颗粒（SP，>1.2微米）、粗胶体（CC，1.2 - 0.45微米）、细胶体（FC，0.45微米至1 kDa分子量，1 Da = 1/16氧原子质量单位）和溶解有机物（DM，<1 kDa分子量）。然后测定渗滤液依次过滤后滤液中的参数，如化学需氧量（COD）、总有机碳（TOC）、总固体（TS）、pH值、总磷（TP）、总氮（TN）、固定固体（FS）、铵离子（NH4+）、无机碳（IC）、总碳（TC）、颜色、浊度和电导率，并建立这些参数与所用膜分子尺寸之间的定量关系。通常，在老港垃圾填埋场采用的生物处理工艺后，COD、NH4+、电导率和磷的总去除率分别为75%、75%、42%和85%。就TOC而言，溶解部分在新鲜渗滤液和处理工艺出水中占主导地位，含量超过47%。随着渗滤液在生物处理阶段进行处理，渗滤液中分子量（MW）百分比分布发生变化。细胶体部分的TOC百分比从6%增加到38%，而溶解部分的TOC百分比从78%下降到47%。渗滤液中的TN也主要存在于溶解部分，占比超过58%，而渗滤液中的TP则与SS和CC部分结合。渗滤液和出水中的正磷酸盐/TP和NH4+/TN的比例分别超过50%和80%。
