利用剩余污泥制备微生物絮凝剂及其絮凝性能与机理分析
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摘要
以城市污水处理厂的剩余活性污泥为原料,以稀盐酸为提取剂制备了污泥絮凝剂,并优化了污泥絮凝剂的制备方法及絮凝条件。当稀盐酸浓度为1. 2 mol/L,破解时间为20 min时,制得的絮凝剂对高岭土悬浮液的絮凝率可达到99. 5%。对于30 g污泥,提取剂稀盐酸的用量为200 m L,浓度为1. 2 mol/L时,连续提取2次,主要絮凝活性成分可基本提取出来。采用加碱溶液的方法对污泥絮凝剂进行提纯,制备得到纯化的絮凝剂PSF-1～3。当絮凝体系pH在4. 0～12. 0时,纯化絮凝剂对高岭土悬浮液的絮凝率均在95%以上。采用红外光谱对3个提纯絮凝剂进行结构解析,结果表明:纯化的污泥絮凝剂中存在O—H和N—H或二者之一,且存及酰胺键,推测絮凝剂的主要絮凝活性成分为多糖和蛋白质。采用扫描电镜对絮凝剂絮凝前后的形貌进行检测,絮凝后高岭土颗粒团聚在絮凝剂周围,由此推测在高岭土和絮凝剂之间产生吸附架桥作用。
Sludge flocculants were prepared from surplus activated sludge of municipal sewage treatment plant with dilute hydrochloric acid as the extracting agent. The preparation methods and flocculation conditions of sludge flocculants were optimized.When the concentration of dilute hydrochloric acid was 1. 2 mol/L and the cracking time was 20 min,the flocculation rate of the prepared flocculants for kaolin suspension could reach 99. 5%. For 30 g sludge,when the dosage of dilute hydrochloric acid was 200 m L and the molar concentration of dilute hydrochloric acid was 1. 2 mol/L,the main flocculating active components could be extracted mainly through continuous extracting twice. The flocculants of sludge were purified by the method of adding alkali solution and three purified flocculants of PSF-1～3 were prepared. When pH of the flocculation system was in the range of 4. 0 ～ 12. 0,the flocculation rates of the purified flocculants were all above 95% for kaolin suspension. The structure of the three purified flocculants were analyzed by infrared spectroscopy. The results indicated that both O—H and N—H,or either of them were present in the purified flocculants. Amido bond also existed in the purified sludge flocculants. It was speculated that the main flocculating active ingredients of the sludge flocculants were polysaccharides and proteins. Scanning electron microscope( SEM) was used to detect the morphology of the flocculants before and after flocculation. After flocculation,the kaolin particles agglomerated around the flocculants. It was inferred that there was adsorption bridging between the kaolin particles and the flocculants.
Sludge flocculants were prepared from surplus activated sludge of municipal sewage treatment plant with dilute hydrochloric acid as the extracting agent. The preparation methods and flocculation conditions of sludge flocculants were optimized.When the concentration of dilute hydrochloric acid was 1. 2 mol/L and the cracking time was 20 min,the flocculation rate of the prepared flocculants for kaolin suspension could reach 99. 5%. For 30 g sludge,when the dosage of dilute hydrochloric acid was 200 m L and the molar concentration of dilute hydrochloric acid was 1. 2 mol/L,the main flocculating active components could be extracted mainly through continuous extracting twice. The flocculants of sludge were purified by the method of adding alkali solution and three purified flocculants of PSF-1～3 were prepared. When pH of the flocculation system was in the range of 4. 0 ～ 12. 0,the flocculation rates of the purified flocculants were all above 95% for kaolin suspension. The structure of the three purified flocculants were analyzed by infrared spectroscopy. The results indicated that both O—H and N—H,or either of them were present in the purified flocculants. Amido bond also existed in the purified sludge flocculants. It was speculated that the main flocculating active ingredients of the sludge flocculants were polysaccharides and proteins. Scanning electron microscope( SEM) was used to detect the morphology of the flocculants before and after flocculation. After flocculation,the kaolin particles agglomerated around the flocculants. It was inferred that there was adsorption bridging between the kaolin particles and the flocculants.
引文
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[2]岳艳利,周林成,王耀龙,等.微生物絮凝剂的制备及其应用研究进展[J].水处理技术,2012,38(1):6-9,16.
[3]李大鹏,马放,侯宁,等.味精废水资源化制备复合型生物絮凝剂[J].湖南大学学报(自然科学版),2009,36(9):78-82.
[4] Wang S G,Gong W X,Liu X W,et al. Production of a novel bioflocculant by culture of Klebsiella mobilis using dairy wastewater[J].Biochemical Engineering Journal,2007,36(2):81-86.
[5]孙杰,张秀红,李星泊,等.液氮冻融破碎生物污泥制备生物絮凝剂[J].环境工程,2013,31(1):126-129.
[6]王菲,杨国录,刘林双,等.城市污泥资源化利用现状及发展探讨[J].南水北调与水利科技,2013,11(2):99-103.
[7] Zheng Y,Ye Z L,Fang X L,et al. Production and characteristics of a bioflocculant produced by Bacillus sp. F19[J]. Bioresource Technology,2008,99(16):7686-7691.
[8] Zhang Z,Bo L,XIA S,et al. Production and application of a novel bioflocculant by multiple-microorganism consortia using brewery wastewater as carbon source[J]. Journal of Environmental Sciences,2007,19(6):667-673.
[9] Sun Jie,Zhang Xiuhong,Miao Xiaojuan,et al. Preparation and characteristics of bioflocculants from excess biological sludge[J].Bioresource Technology,2012,126(12):362-366.
[10]李海松,闻岳,曹阿生,等.胞外多聚物对活性污泥絮凝性能影响的研究进展[J].环境污染与防治,2012,34(7):64-69,89.
[11]欧国荣,陈奇洲.生活水污泥油化试验研究[J].环境污染与防治,1996,18(4):20-21,45.
[12]朱艳彬,冯旻,杨基先,等.复合型生物絮凝剂产生菌筛选及絮凝机理研究[J].哈尔滨工业大学学报,2004,36(6):759-762.