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饮用水安全关系着人们的身体健康,生命安全。随着社会发展、科技进步,以地表水为代表的各类水源中发现了多种的新型污染物,如内分泌干扰物、药品、甜味剂、个人护理产品等[1-2]。这些新型污染物的存在不仅会对人体产生危害并且降低消费者对饮用水的信心。由于常规给水处理工艺(混凝、沉淀、过滤和消毒)的主要功能是去除细菌和降低浊度等,对有机物尤其是溶解性有机物(dissolved organic carbon, DOC)的去除能力很低,而深度处理,例如活性炭吸附、高级氧化等可以实现更好的去除效果[3-4]。综合国内外研究,在新型污染物暴露的情况下,具备深度处理工艺的水厂比常规工艺的水厂的抗风险能力更强,受新型污染物威胁的风险更小[5]。因此,饮用水深度处理工艺已经成为给水工艺中不可或缺的一环,尤其是集吸附与生物降解于一体的生物活性炭(biological activated carbon, BAC)工艺,无论是对传统水处理指标还是对新型污染物去除均有较好的效果[6-7];由于BAC工艺具有应用范围广、水源水质针对性强、水质保障能力强、出水稳定性高、技术成熟等优点,已经成为我国给水深度处理的主推广技术[8]。截至2020年底,全国已有近130余座水厂采用BAC工艺进行深度处理,处理能力已达3 580万m3·d−1,占日供水能力的35%以上[9],如苏州市的供水水厂已经全面实现了BAC深度工艺,出厂水水质达到了高品质饮用水的标准[10],这表明BAC工艺在我国给水工艺中的优势地位与普适性。
然而由于资源的有限性、可持续发展的紧迫性,作为BAC工艺中关键净水材料的活性炭,其应用效率有待进一步研究[11-15]。基于此,本研究以新疆煤基压块活性炭为例,探究2种不同指标活性炭的小试BAC工艺应用效果,以期为BAC工艺中活性炭的靶向选择提供借鉴和指导。
新疆煤基压块活性炭在BAC工艺中的应用
Application of Xinjiang coal-based briquetted activated carbon in BAC process
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摘要: 鉴于新疆丰富的煤炭资源,本研究对由2种不同指标新疆煤基压块活性炭(LBC和HBC)组成的上向流活性炭柱构成的小试生物活性炭(biological activated carbon, BAC)工艺进行了为期约300 d的实验研究。考察了2种不同指标的压块活性炭柱(LBC-O3与HBC-O3)的运行情况。结果表明,LBC-O3对于CODMn的去除效果优于HBC-O3(进水平均值为1.56 mg·L−1,出水平均值为0.55 mg·L−1);而HBC-O3对于UV254所代表有机物去除效果优于LBC-O3(进水平均值为0.053 cm−1,出水平均值为0.005 cm−1)。LBC-O3对CODMn的较佳去除性能,促成了活性炭表面微生物量的生长,进而构成了吸附和生物降解的良性循环;而兼具发达次微孔和中孔结构的HBC-O3对UV254代表的有机物表现出了靶向吸附性;微生物检测结果和炭柱出水中溶解性有机物的光谱特性分析验证了该结论。因此,结合目标水体中污染物的特性靶向选择相应指标(孔隙结构)的压块活性炭可取得更佳的BAC工艺处理效果:提高污染物去除率、节约资源,符合双碳目标。Abstract: In view of the rich coal resources in Xinjiang, a lab-scale biological activated carbon (BAC) process consisting of two up-flow columns was conducted for about 300 days and its running status was investigated, in which two kinds of Xinjiang coal-based briquetted activated carbon (LBC and HBC) with different indicators were packed, denoted as LBC-O3 and HBC-O3 columns, respectively. The results showed that the CODMn removal effect by LBC-O3 was better than that of HBC-O3 (the average value of influent was 1.56 mg·L−1, and the average value of effluent was 0.55 mg·L−1). The removal effect of organic compounds represented with UV254 by HBC-O3 was better than that of LBC-O3 (the average value of influent was 0.053 cm−1, and the average value of effluent was 0.005 cm−1). The better adsorption performance of LBC-O3 on organic compounds represented by CODMn promoted the growth of microbial biomass on the surface of activated carbon, thus forming a good cycle of adsorption and biodegradation. HBC-O3 with developed sub-microporous and mesoporous structures showed targeted adsorption to organic compounds represented by UV254. The results of microbial detection during BAC process and three dimensional fluorescence spectra of influent and effluent of BAC columns confirmed the conclusion. Therefore, combining with the characteristics of pollutants in the target water, the targeted selection of the briquetted activated carbon was made and could achieve better BAC process treatment effect, which can improve pollutant removal rate and save resources, being in line with the goal of carbon emission peak and carbon neutrality.
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表 1 LBC与HBC的孔隙结构表征
Table 1. Characterization of pore structure of LBC and HBC
编号 比表面积/
(cm2·g−1)总孔容/
(cm3·g−1)微孔容积/
(cm3·g−1)LBC/HBC
微孔含量比中孔容积/
(cm3·g−1)LBC/HBC
中孔含量比平均孔径/
nmLBC 1 069 0.656 4 0.366 0 1.0 0.237 9 1.0 2.457 HBC 1 331 0.825 5 0.438 9 1.2 0.305 8 1.29 2.481 -
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