Town Office for Physical Planning and Environmental Protection, Velika Gorica County, Trg kralja Tomislava 34, 10410 Velika Gorica, Croatia.
Sci Total Environ. 2013 Mar 1;447:17-24. doi: 10.1016/j.scitotenv.2012.12.078. Epub 2013 Jan 31.
In this paper, monitoring of total metal concentration in sludge samples from wastewater treatment process is elaborated. The presented results summarize the analyses of sludge samples in a period from 2008 to 2012. Possible sources of pollutions are given. Primarily, waste solid samples were collected from different pretreatment steps: (A) coarse grid, (B) fine grid and (C) aerated sand grease grid. Samples of A and B followed a repeatable pattern in 2008 and 2010. According to the results from 2008, samples of C contained measurable concentration of the following metals (mg/kg dry matter): Zn (21), Ni (1.05) and Ba (14.9). Several types of sludge samples were analyzed: fresh raw sludge (PS; 6-12 hour old), the sludge from the digester for anaerobic sludge treatment (DS; 48-72 hour old), samples from lagoons where the sludge is temporarily deposited (DOS and DOSold; 30-120 days) and sludge samples from agricultural areas (AA; aged over 180 days). Additionally, samples of dehydrated sludge (DEHS and DEHSold; 90-180 days) were collected upon construction of equipment for sludge dehydration in 2011. An analysis of total metal concentrations for Cu, Zn, Cr, Pb, Ni, Hg, Cd, Ba, As, Se, Sb, Co, Mo, Fe and Mn was performed by flame atomic absorption spectrometry (FAAS) and inductively coupled plasma-optical emission spectrometry (ICP-OES). The most recent results (year 2011) indicated a high concentration of heavy metals in PS samples, exceeding the MCLs (mg/kg dry matter): Cu (2122), Zn (5945), Hg (13.67) and Cd (6.29). In 2012 (until July), only a concentration of Cu exceeded MCL (928.75 and 1230.5 in DS and DEHS, respectively). A composition of sludge was variable through time, offering the limited possibility for future prediction. The sludge is being considered as a hazardous waste and a subject of discussion regarding disposal.
本文详细阐述了监测污水处理过程中污泥样品中总金属浓度的方法。所呈现的结果总结了 2008 年至 2012 年期间对污泥样品的分析。给出了可能的污染源。主要从不同的预处理步骤收集固体废物样品：(A)粗格栅，(B)细格栅和(C)充气砂油脂格栅。2008 年和 2010 年，A 和 B 组的样品重复出现相同的模式。根据 2008 年的结果，C 组样品含有以下金属的可测量浓度（mg/kg 干物质）：Zn（21）、Ni（1.05）和 Ba（14.9）。分析了几种类型的污泥样品：新鲜原污泥（PS；6-12 小时）、用于厌氧污泥处理的消化池中的污泥（DS；48-72 小时）、暂时储存污泥的池塘中的样品（DOS 和 DOSold；30-120 天）和农业区的污泥样品（AA；老化超过 180 天）。此外，2011 年在建造污泥脱水设备时收集了脱水污泥（DEHS 和 DEHSold；90-180 天）的样品。通过火焰原子吸收光谱法（FAAS）和电感耦合等离子体-光学发射光谱法（ICP-OES）对 Cu、Zn、Cr、Pb、Ni、Hg、Cd、Ba、As、Se、Sb、Co、Mo、Fe 和 Mn 的总金属浓度进行了分析。最近的结果（2011 年）表明 PS 样品中重金属浓度很高，超过了 MCLs（mg/kg 干物质）：Cu（2122）、Zn（5945）、Hg（13.67）和 Cd（6.29）。2012 年（截至 7 月），仅 DS 和 DEHS 中的 Cu 浓度超过 MCL（分别为 928.75 和 1230.5）。污泥的成分随时间而变化，为未来的预测提供了有限的可能性。污泥被认为是危险废物，也是处置讨论的主题。
