废水处理系统中生物聚集体胞外多聚物研究进展

胞外多聚物(Extracellular polymeric substances,EPS)是废水生物处理系统中生物聚集体(包括絮体污泥、生物膜、颗粒污泥等)的重要组成部分,直接包裹于微生物细胞壁外,其理化性质及所处的特殊位置决定了它在生物聚集体中的重要作用.综述了EPS对废水生物处理系统污泥沉降性能、脱水性以及膜生物反应器膜污染影响的相关研究,分析认为EPS组成与结构特性改变污泥表面电位、疏水性等,进而影响污泥沉降与脱水性能、膜污染程度;以好氧颗粒污泥为典型的生物聚集体代表,总结了EPS组分含量与分布对颗粒污泥的形成与结构稳定性的影响,并在EPS提取方法标准化、现代理化技术与分子生物学技术综合分析等方面进行了展望,进一步的研究有望揭示生物絮凝体形成过程EPS的产生与调控机制.     

新型膜分离技术及其工业中的应用

用膜法来处理废水有高效、低能耗和易操作处理效率高的优点,而且有利于回收废液中的物质,在水处理中有着广阔的应用前景.在介绍常规和新型膜分离技术的基础上,对新型膜分离技术在工业中的发展及应用进行了综述.     

地表臭氧增加对黄花夹竹桃和芒果叶片膜脂过氧化程度和保护酶活性的影响

以黄花夹竹桃（Thevetia peruviana（Pers.）k.Schum.）和芒果（Mangifera indica L.）苗木为材料,研究4种臭氧（O3）体积分数[环境大气NF,φ（O3）=10×10-9~20×10-9;低体积分数处理E50,φ（O3）=50×10-9;中体积分数处理E100,φ（O3）=100×10-9;高体积分数处理E200,φ（O3）=200×10-9]下两种植物叶片膜脂过氧化程度、可溶性蛋白质质量分数、可溶性糖质量分数和保护酶活性的变化情况,旨在揭示地表臭氧体积分数升高条件下2种植物生理代谢活动变化机理及响应规律。结果表明：随臭氧体积分数的增加,2种植物丙二醛含量和膜透性均逐渐上升,且与臭氧体积分数呈显著正相关关系,说明两种植物膜脂过氧化程度加剧;低体积分数O3处理时两种植物可溶性蛋白质量分数均逐渐下降,高φ（O3）处理后小幅回升;黄花夹竹桃可溶性糖质量分数逐渐下降,芒果先上升后下降;2种植物的POD活性均显著上升,但上升幅度有较大差异;2种植物的CAT活性均呈先升高再降低的趋势。研究表明,不同体积分数的臭氧暴露下,黄花夹竹桃和芒果均受到不同程度的伤害,芒果对臭氧表现出较强的抗性,黄花夹竹桃对臭氧较敏感。     

冷藏技术对发光细菌活性及毒性测试性能的影响

由于发光细菌的在线毒性监测技术受到了细菌生物活性稳定性保持问题的制约,探索一种脱脂牛奶菌悬液冷藏复苏方法,以提高发光细菌活性的保持时间。比较了明亮发光杆菌新鲜菌液冷藏、冻干粉菌悬液冷藏和脱脂牛奶菌悬液冷藏对发光细菌生物活性的影响,同时,比较了不同渗透压调节液对菌悬液急性毒性测试的灵敏度和稳定性的影响。结果表明,质量分数为25%的脱脂牛奶可提高发光细菌生物活性的稳定性,菌悬液冷藏7d后复苏,相对发光率仍可达92%。2%NaCl和10%蔗糖为渗透压调节液时,冷藏至第7天的发光细菌脱脂牛奶菌悬液对重金属毒性测试的灵敏度,与新鲜菌液基本相同,但添加蔗糖降低了其对有机物的测试灵敏度。利用发光细菌脱脂牛奶冷藏菌悬液对Zn~(2+)进行连续7d的毒性测试,EC_(50)的变异系数小于15%,结果稳定性良好。     

光催化膜反应器的设计及其在水处理中的应用

作为一种新型的水处理装置,光催化膜反应器具有反应迅速、降解效率高、降解彻底、无二次污染等特点,在节水减排、微污染水处理、中水回用等方面具有重要的应用价值。总结目前国内外各种不同类型的光催化膜反应器的设计、特点及在水处理中的应用情况,并对其今后的发展提出建议。     

混凝-膜过滤中滤饼层对双酚A的去除强化作用研究

以聚合氯化铝(PAC)和氯化铁(FeCl3)为混凝剂,分析了双酚A(BPA)在1g/L高岭土溶液混凝过程中的特征.并借助循环错流过滤强化污染层累积的方法,评价产生滤饼层的微滤(MF)膜对BPA的截留效果.结果表明:清洁的微滤膜过滤BPA溶液在短时间内达到截留吸附饱和,之后其对BPA的吸附截留作用显著降低;混凝絮体混合液经膜过滤时产生的污染层有利于BPA的去除,且单独混凝对BPA去除率最高的混凝剂投加量下进行膜过滤时的阻力较小.PAC混凝—膜过滤后BPA去除率比单独混凝提高了34.30%;FeCl3混凝—膜过滤后BPA去除率比单独混凝提高了28.38%.初始BPA浓度对混凝-膜过滤去除率有一定影响,BPA浓度为100μg/L时,比BPA浓度为5mg/L时采用2种混凝-微滤膜过滤方式去除率均有提高.     

软弱基底排土场变形破坏治理措施研究

针对软弱基底露天矿排土场普遍存在的变形破坏问题,结合胜利东二露天矿南排土场南帮边坡的工程实际,基于极限平衡理论,给出了通过探槽及滑坡变形反分析综合确定基底赋存条件及抗剪强度指标的方法;提出了对软弱基底排土场的变形治理措施;根据已有监测数据,对南帮边坡治理效果进行了评价。结果表明:在实施削坡减载措施后,各地表监测点的累计位移趋于平缓,边坡治理措施效果明显,解决了胜利东二露天矿迫切的安全问题,为同样具有软弱基底的其他露天矿排土场变形及破坏治理提供了指导。     

Effect of iron addition on the performance of anoxic-oxic membrane process and biological phosphorus removal北大核心CSCD

In order to solve the problem of poor treatment of phosphorus in membrane bioreactor (MBR) with long sludge retention time (SRT), a ferric salt was added to enhance phosphorus removal; FeCl36H2O (Fe/P = 2.0) was added to the reactor. The removal efficiency of nitrogen, organic matters, and phosphorus in the MBR was investigated systematically. Moreover, this study focused on the membrane performance, the change of active sludge flora, and the effect of adding a ferric salt on membrane fouling before and after the addition. It was seen that adding the ferric salt could not affect the removal of COD and NH4 +-N and the removal rate of COD and NH4 +-N reached over 90%. However, the average removal rate of phosphorus was 52%, while the removal rate increased by nearly 40% after adding the ferric salt. The effects of adding ferric salts on the dominant bacteria and biological phosphorus removal of activated sludge were further studied. The results showed that the addition of ferric salt (Fe/P = 2.0) decreased the diversity of active sludge flora and relative abundance of some phosphorusaccumulating organisms and had a negative effect on biological phosphorus removal. The analysis of transmembrane pressure difference (TMP) recording revealed that the concentration of iron salts did not exacerbate membrane fouling. The results showed that the concentration of iron salts entering the membrane bioreactor would reduce the relative abundance and phosphorus removal efficiency of the activated sludge in the system to a certain extent, but it had no obvious effect on membrane fouling. It allowed the effluent to attain acceptable standards, especially with respect to phosphorus removal efficiency. © 2018 Science Press. All rights reserved.     

Energy reduction of a submerged membrane bioreactor using a polytetrafluoroethylene (PTFE) hollow-fiber membrane

The fiber length and packing density of the PTFE membrane element were increased. The MBR was stably operated under an SAD^m of 0.13 m³·m^-2·hr^-1. Specific energy consumption was estimated to be less than 0.4 kWh·m^-3. In this study, we modified a polytetrafluoroethylene (PTFE) hollow-fiber membrane element used for submerged membrane bioreactors (MBRs) to reduce the energy consumption during MBR processes. The high mechanical strength of the PTFE membrane made it possible to increase the effective length of the membrane fiber from 2 to 3 m. In addition, the packing density was increased by 20% by optimizing the membrane element configuration. These modifications improve the efficiency of membrane cleaning associated with aeration. The target of specific energy consumption was less than 0.4 kWh·m^-3 in this study. The continuous operation of a pilot MBR treating real municipal wastewater revealed that the MBR utilizing the modified membrane element can be stably operated under a specific air demand per membrane surface area (SAD_m) of 0.13 m³·m^-2·hr^-1 when the daily-averaged membrane fluxes for the constant flow rate and flow rate fluctuating modes of operation were set to 0.6 and 0.5 m³·m^-2·d^-1, respectively. The specific energy consumption under these operating conditions was estimated to be less than 0.37 kWh·m^-3. These results strongly suggest that operating an MBR equipped with the modified membrane element with a specific energy consumption of less than 0.4 kWh·m^-3 is highly possible.     

吸收液对中空纤维膜接触器回收尿液中氨氮的影响

采用中空纤维膜接触器（Hollow Fiber Membrane Contactor, HFMC）回收尿液中的氨氮,系统研究了吸收液类型（H₃PO₄、H₂SO₄和HNO₃）对氨回收效能、水蒸气的跨膜通量和所获液体肥料的影响.结果表明,使用H₂SO₄作为吸收液时氨氮回收效能最优,其次是H₃PO₄和HNO₃.当采用H₂SO₄为吸收液时,氨氮回收率、氨跨膜通量和传质系数分别为84.49%±0.01%、22.92 g·m^-2·h^-1和2.37×10^-6 m·s^-1.HNO₃的挥发性使其从吸收液侧反向跨膜至料液侧,导致氨跨膜传质驱动力变小;此外,NH₃和HNO₃会在膜孔中反应并生成NH₄NO₃气溶胶,增加氨在膜孔中的传质阻力,导致氨氮的回收效能降低.对采用不同吸收液时膜两侧的水的活度差和理论水通量进行了计算,结果表明,随着氨氮的不断跨膜吸收,膜两侧的活度差和水通量逐渐增大,实验结束时水通量分别为7.44×10^-2 kg·m^-2·h^-1（H₃PO₄）、9.06×10^-2 kg·m^-2·h^-1（H₂SO₄）和2.00×10^-2 kg·m^-2·h^-1（HNO₃）.肥料组分分析表明,以H₂SO₄和HNO₃为吸收液可以获得仅含N素的单一液体肥料,以H₃PO₄作吸收液可获得N-P复合肥,（NH₄）₂HPO₄和NH₄H₂PO₄所占的比例分别为88.33%和11.67%.