Van de Velden M, Dewil R, Baeyens J, Josson L, Lanssens P
University of Birmingham, School of Chemical Engineering, Edgbaston, Birmingham B15 2TT, United Kingdom.
J Hazard Mater. 2008 Feb 28;151(1):96-102. doi: 10.1016/j.jhazmat.2007.05.056. Epub 2007 May 24.
During combustion of wastewater treatment sludge, the inorganic constituents are converted into ash which contains the major fraction of the heavy metals present. The behaviour of heavy metals in combustion processes has been studied extensively for mostly coal combustion and waste incineration. For biomass and sludge, literature data are scarce and mostly limited to laboratory experiments. The present paper assesses the partitioning of eight heavy metals (Hg, As, Cd, Cu, Pb, Cr, Ni and Zn) in the different residues from a large-scale fluidized bed sludge combustor of 4.4 m i.d. The origin of the sludge is mostly from treating urban wastewaters (>90%), although some mixed sludge (urban+industrial, <10%) is also burnt. The different residues (bottom ash, fly ash, filter cake, scrubber effluent and stack emissions) were sampled and analysed during 33 weeks, spread over a period of 1 year. The mass balance of relevant heavy metals closes for 96.5%, inaccuracies being related to the unsteadiness of the process, the accuracy of the mass flow data monitored at the plant, and on collecting representative samples. It is also shown that all heavy metals under scrutiny, except Hg, are concentrated in the fly ash as collected in the electrostatic precipitator.
在污水处理污泥燃烧过程中，无机成分会转化为灰分，其中含有大部分存在的重金属。对于大多数煤燃烧和垃圾焚烧，燃烧过程中重金属的行为已得到广泛研究。对于生物质和污泥，文献数据稀缺，且大多限于实验室实验。本文评估了内径为4.4米的大型流化床污泥焚烧炉不同残渣中八种重金属（汞、砷、镉、铜、铅、铬、镍和锌）的分配情况。污泥主要来源于城市污水处理（>90%），不过也焚烧了一些混合污泥（城市+工业，<10%）。在一年的时间里，对33周内产生的不同残渣（底灰、飞灰、滤饼、洗涤器流出物和烟囱排放物）进行了采样和分析。相关重金属的质量平衡闭合率为96.5%，误差与过程的不稳定性、工厂监测的质量流量数据的准确性以及采集代表性样品有关。研究还表明，除汞外，所有受审查的重金属都集中在静电除尘器收集的飞灰中。
