Recovering humic substances from the dewatering effluent of thermally treated sludge and its performance as an organic fertilizer

The biologic treatment of the dewatering effluent from thermally treated sludge is difficult due to the high concentration of refractory humic substances. On the other hand, humic substances are an important source of organic fertilizer. In this study, a novel process using ferric coagulant was developed to recover humic substances from dewatering effluent for use as an organic fertilizer. When ferric coagulant was applied to raw dewatering effluent, up to 70% of humic substances were enmeshed by hydrolyzed ferric ions at an optimum pH of 4.5. The proper mass ratio of iron ions to humic substances was 0.6. In the recovered material, humic substances accounted for 24.2% of the total dry solids, and the amount of phosphorus (equivalent phosphorus pentoxide) was 6.2%. Heavy metals and other components all met the legal requirements for organic fertilizer. When the recovered material was applied to soybeans, the germination and growth of the seeds was significantly improved.     

Distribution and sources of polyfluoroalkyl substances (PFAS) in the River Rhine watershed

The concentration profile of 40 polyfluoroalkyl substances (PFAS) in surface water along the River Rhine watershed from the Lake Constance to the North Sea was investigated. The aim of the study was to investigate the influence of point as well as diffuse sources, to estimate fluxes of PFAS into the North Sea and to identify replacement compounds of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). In addition, an interlaboratory comparison of the method performance was conducted. The PFAS pattern was dominated by perfluorobutane sulfonate (PFBS) and perfluorobutanoic acid (PFBA) with concentrations up to 181 ng/L and 335 ng/L, respectively, which originated from industrial point sources. Fluxes of ΣPFAS were estimated to be ∼6 tonnes/year which is much higher than previous estimations. Both, the River Rhine and the River Scheldt, seem to act as important sources of PFAS into the North Sea.     

A/O1/H/O2工艺处理焦化废水硝化过程的实现及其抑制

针对焦化废水中的有毒污染物会对敏感易受干扰的硝化细菌产生不利影响从而破坏硝化过程稳定性的现象,采用A/O1/H/O2工艺处理焦化废水的实际工程为研究对象,根据工程运行的水质监测数据分析,发现几种主要污染物的浓度变化会对二级好氧段的硝化过程产生抑制影响。序批式毒性抑制实验结果表明,苯酚、硫氰化物和喹啉对硝化过程具有毒性抑制作用,半抑制浓度EC50分别为34.26、278.5和73.24 mg/L。当二级好氧工艺段运行正常时（C/N约4.3/1,pH8～8.5,DO 4～4.5 mg/L）,出水氨氮浓度可低于5 mg/L,是由于焦化废水经厌氧/好氧/水解工艺后毒物浓度大幅下降,毒性得到削减,表明焦化废水生物处理A/O1/H/O2组合流化床工艺具有较强抵抗毒物抑制并实现高效的硝化作用。     

氧化亚铁硫杆菌浸铜研究及胞外多聚物的作用

为了获得氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,A.f)以及胞外多聚物(extracellular polymeric sub-stances,EPS)对铜浸出的作用结果,进行了透析袋实验,设置2个处理,2者的浸出液均为成熟菌液,但一个将铜片装入透析袋中以隔离A.f及EPS与铜的直接接触。结果表明:(1)菌液的处理和加透析袋的处理中铜都得到了浸出,240 h铜的浸出浓度分别为6 796 mg/L和1 366 mg/L,可知A.f及EPS与铜片直接接触能促进铜的浸出;(2)透析袋的处理中Fe3+保持较高浓度,说明Fe3+与EPS络合后被阻挡在透析袋外面从而不能与铜反应,可知EPS在A.f浸铜中起了媒介载体的作用;(3)2者的SEM图表明无透析袋的处理A.f与铜在实验初期发生了吸附,实验后期则无,实验初期铜快速浸出是由于传质距离短,而后期速度变缓是由于传质距离增大。     

Watershed-based riverine discharge loads and emission factor of perfluorinated surfactants in Korean peninsula

Long-range transport of and exposure to perfluorinated substances (PFSs) strongly depend on their emission mode. In the present study, watershed-based riverine discharge loads and emission factors are estimated for perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorohexylsulfonate (PFHxS), and perfluorooctylsulfonate (PFOS) by using spatially distributed data of chemical concentrations together with water flows and a geographic information system (GIS). Average per capita emissions (emission factor, μg capita⁻¹ d⁻¹) are 75 for PFOA, 36 for PFNA, 17 for PFHxS, and 43 for PFOS, which are several times lower than the estimates for Japan and the European continent. A relatively uniform distribution is observed for PFHxS and PFOS emission factors, while elevated values of PFOA and PFNA predominate in one of eight river basins. This may indicate the leading contribution of diffusive sources (e.g. nonpoint source) for PFHxS and PFOS versus the presence of localized point sources for PFOA and PFNA. The lower-upper bound of total riverine loads discharged annually from the Korean peninsula are in the range of 0.53-1.3 tons for PFOA, 0.09-0.60 tons for PFNA, 0.07-0.29 tons for PFHxS, and 0.19-0.73 tons for PFOS, accounting for <1% of global annual emissions. Furthermore, these riverine discharge loads are significantly greater than the discharge loads from a wastewater treatment plant, indicating the necessity of further study of nonpoint sources.     

臭氧氧化法处理反渗透浓缩垃圾渗滤液

采用臭氧氧化法处理经反渗透膜处理后的浓缩垃圾渗滤液,考察了反应时间、臭氧投量、pH和温度对COD,色度以及浓缩液中腐殖酸的去除影响,通过BOD₅/COD变化分析了臭氧氧化对浓缩液生化性的提高作用。结果表明：在pH 8.0,温度30℃,臭氧投量5 g/h,反应时间90 min的条件下,浓缩液的COD、色度以及浓缩液中腐殖酸的去除率分别达到67.6%、98.0%和86.1%, BOD₅/COD从0.008提升到0.26,生化性有很大提高。     

胞外多聚物对活性污泥絮凝性能影响的研究进展

活性污泥的絮凝性能直接影响出水SS浓度,而胞外多聚物(EPS)是影响活性污泥絮凝性能的重要因素。从EPS的组分及其化学性质入手,结合现有的活性污泥絮凝机制评价了EPS在活性污泥絮凝性能中的重要作用,系统分析了EPS组分对污泥絮凝性能的影响,以及EPS产量和组分的影响因素,并就近年来的研究热点———松散层EPS、致密层EPS与活性污泥絮凝性能的关系进行了归纳,还对利用EPS提高活性污泥絮凝性能的技术应用进行了总结。最后,对该领域的研究方向进行了展望。     

有机负荷对厌氧流化床反应器处理模拟味精废水的影响

在中温(35±1℃)条件下,以新型橡胶颗粒为载体的厌氧流化床(AFB)反应器处理模拟味精废水为研究体系,考察有机负荷(OLR)由2.08 kg/(m3.d)提高到19.20 kg/(m3.d)期间,污染物去除率、胞外聚合物(EPS)含量及其在生物膜和混合液中的分布、生物膜中MLVSS含量及脱氢酶活性等的变化情况。结果表明,随有机负荷增加,污染物去除稳定,COD去除率维持在80%左右;EPS在生物膜中的量大于在混合液中的量,并以蛋白质为主要成分,但其总量呈递减趋势;当有机负荷为19.20 kg/(m3.d)时,生物膜中MLVSS含量约为23.1 mg/g载体,脱氢酶活性则为22.6 mg/(L.h);载体生物膜的生物相以独缩虫属、聚缩虫属、累枝虫属和钟虫等为主。     

共存物质对钢渣除磷的影响

研究了pH、共存离子（Cl^-、NO3^-、SO4^2-、F^-、HCO3^-）和腐植酸对钢渣吸附除磷的影响。结合吸附饱和钢渣上的磷形态分析了产生影响的原因,采用SEM-EDS（扫描电子显微镜-X射线能谱分析）对吸附磷酸盐前后钢渣表面的微观形态特征进行观察。结果表明：钢渣对磷酸盐具有很好的去除效果,吸附饱和钢渣中的磷主要以Ca—P形式存在。钢渣吸附磷酸盐最适初始pH为3～5,高pH抑制Ca—P的生成,对吸附不利。NHf的存在提高了Ca—P含量,从而促进钢渣对磷酸盐的吸附。共存阴离子Cl^-、NO3^-、SO4^2-对钢渣吸附磷酸盐没有影响,但是F^-和HCO3^-明显抑制Ca—P的生成,从而减少了钢渣对磷酸盐的吸附。腐植酸的存在显著抑制了Ca—P和O-P的生成,使钢渣对磷酸盐的吸附量大大减小。     

附着性胞外多聚物对HMBR膜污染控制性能的影响

采用复合式膜生物反应器（HMBR）处理城市生活污水,对附着性胞外多聚物影响HMBR膜污染控制性能的作用机理进行了研究。实验结果表明,HMBR中附着性胞外多聚物、松散附着性胞外多聚物和紧密附着性胞外多聚物的浓度比常规膜生物反应器分别降低了10．0％、43．6％和2．1％。附着性胞外多聚物与膜表面滤饼层污泥比阻的关系较为密切,随着其浓度逐渐降低,滤饼层污泥比阻相应减小。与紧密附着性胞外多聚物相比,松散附着性胞外多聚物对滤饼层污泥比阻的影响程度更深。因此,随着反应器中附着性胞外多聚物特别是松散附着性胞外多聚物浓度的降低,HMBR的膜污染控制性能增强,反应器中膜表面的滤饼层阻力比常规膜生物反应器降低了56．9％。