纳米颗粒的危害及在水体中的去除研究进展

纳米颗粒具有独特的物理化学性质且种类较多,广泛应用于多个领域.在使用的同时,纳米颗粒不可避免地通过各种途径进入水环境中,进而对生物及人类造成危害.针对近来出现的纳米颗粒,介绍了其对环境的影响及在水体中的主要去除方法,并展望了水环境中纳米颗粒的研究方向.     

NaOH碱促热解磷酸铵镁产物沉氨性能研究

药剂费用过高是阻碍磷酸铵镁结晶技术应用的难题之一,通过磷酸铵镁热解产物循环沉氨可降低药剂费用.但湿法热解会生成热稳定性更好的NH4MgPO4·H2O,从而增加了磷酸铵镁热解的能耗.采用干法热解时,由于不引入额外的水分子,可以降低磷酸铵镁的热解温度.同时,在磷酸铰镁热解过程中加入NaOH碱促试剂,可有效促进磷酸铵镁释放NH4+,提高热解产物的沉氨效率,但同时上清液磷酸盐残留量也随NaOH添加量和热解温度提高而增加.热解温度为110℃时,直接热解产物沉氨效率为84％,而NaOH碱促热解产物沉氨率达到87％(NaOH与NH4+物质的量比为1:1),但此时上清液磷酸盐残留质量浓度达到2.3 mg/L,略高于GB 8978-1996《国家污水综合排放标准》的1.0 mg/L,方便废水的后续处理.     

进水渗滤液总氮和BOD5/TN对填埋场反应器反硝化和厌氧氨氧化协同脱氮的影响

晚期垃圾渗滤液具有氨氮浓度较高、碳氮比(C/N)较低和可生化性差的特点,生物脱氮较困难.本文研究了改变进水总氮负荷和BOD5/TN比值对填埋场生物反应器处理垃圾渗滤液的脱氮效果的影响.结果表明,总氮负荷为15~25g·(m3·d)-1的范围内时,总氮去除负荷稳定为10~12 g·(m3·d)-1,但是总氮去除率随着负荷的增加从67.7%下降至60.2%,说明在一定范围总氮负荷的增加会降低总氮去除率,但不会影响去除负荷.当改变进水的BOD5/TN从0.3提高到0.4后,总氮负荷为9 g·(m3·d)-1时的厌氧、准好氧反应器,总氮去除率可从79.9%分别提高到89.9%和86.2%,表明提高BOD5/TN能够有效促进填埋场生物反应器对总氮污染物的去除,并且厌氧条件下效果更好.脱氮途径分析表明,填埋场生物反应器中厌氧氨氧化和反硝化作用可以协同脱氮.     

Phosphate removal using aerobic bacterial consortium and pure cultures isolated from activated sludge

In the present study, an attempt is made to evaluate the kinetics of biological phosphate removal using a bacterial consortium of activated sludge, as well as screening for dominant polyphosphates accumulating bacteria. The results showed an efficient phosphate uptake (P < 0.001) of the consortium, with rates related to the initial concentration of both phosphate and carbon sources. Short chain volatile fatty acids presented the suitable substrates for enhanced biological phosphorus removal, of which maximum yield reached 99.23% and 78.51% in basal salt medium supplemented with 0.5% of sodium acetate and lactate respectively. Fifteen phosphate-accumulating bacteria were isolated from the activated sludge and only four isolates were selected and characterized as Pseudomonas aeruginosa AS1, Moraxella lacunata AS2, Acinetobater junii AS3 and Alcaligenes denitrificans AS4. The highest efficiency of phosphate uptake using pure culture was achieved with Ac. junii AS3 (83.36) followed by P. aeruginosa AS1 (81.78%), Al. denitrificans AS4 (76.72%), and M. lacunata AS2 with 50.6%.     

利用Cu-Fe复合金属氧化物净化水中的磷

研究了利用Cu-Fe复合金属氧化物净化水中磷的过程。实验结果表明,在吸附剂的制备过程中,加入Cu可以显著提高吸附剂对水中磷的净化效率,Cu的适宜加入量为Cu/Fe摩尔比1∶2。在磷净化过程中,p H值对Cu-Fe复合金属氧化物的净化效率有显著影响,较低的p H值有利于磷的净化;水中磷的净化率随吸附剂用量的增加而增加,适宜的投加量为0.2 g/100 m L;吸附剂对水中磷的净化速度较快,磷的吸附率在5 min内达到87.08%,吸附2 h达到平衡,磷的净化率为98.85%;Cu-Fe复合金属氧化物净化水中磷的吸附等温线符合Langmuir方程,磷的最大吸附量为11.36 mg/g。     

我国燃煤电厂除尘技术路线选择问题分析

通过文献调研分析了影响我国燃煤电厂除尘技术路线选择的主要问题,从煤质含硫量、粉尘比电阻、粉尘粒径分布三方面研究结果表明电除尘技术对我国煤种的适应性较差,无法满足严格的排放标准;另外,通过前人对比不同除尘方式协同脱汞效果和对下游设备保护作用的研究成果,结果表明袋式除尘器具有更好的协同脱汞作用,更高的除尘效率并赋予湿法脱硫设备长期可靠运行。     

Flower-, wire-, and sheet-like MnO2-deposited diatomites: Highly efficient absorbents for the removal of Cr(VI)

Flower-, wire-, and sheet-like MnO₂-deposited diatomites have been prepared using a hydrothermal method with Mn(Ac)₂, KMnO₄ and/or MnSO₄ as Mn source and diatomite as support. Physical properties of the materials were characterized by means of numerous analytical techniques, and their behaviors in the adsorption of chromium(VI) were evaluated. It is shown that the MnO₂-deposited diatomite samples with different morphologies possessed high surface areas and abundant surface hydroxyl groups (especially the wire-like MnO₂/diatomite sample). The wire-like MnO₂/diatomite sample showed the best performance in the removal of Cr(VI), giving the maximum Cr(VI) adsorption capacity of 101 mg/g.     

Flower-, wire-, and sheet-like MnO2-deposited diatomites: Highly efficient absorbents for the removal of Cr(VI)

Flower-, wire-, and sheet-like MnO₂-deposited diatomites have been prepared using a hydrothermal method with Mn(Ac)₂, KMnO₄ and/or MnSO₄ as Mn source and diatomite as support. Physical properties of the materials were characterized by means of numerous analytical techniques, and their behaviors in the adsorption of chromium(VI) were evaluated. It is shown that the MnO₂-deposited diatomite samples with different morphologies possessed high surface areas and abundant surface hydroxyl groups (especially the wire-like MnO₂/diatomite sample). Thewire-like MnO₂/diatomite sample showed the best performance in the removal of Cr(VI), giving the maximum Cr(VI) adsorption capacity of 101 mg/g.     

Nitrogen removal from coal gasification wastewater by activated carbon technologies combined with short-cut nitrogen removal process

A system combining granular activated carbon and powdered activated carbon technologies along with shortcut biological nitrogen removal （GAC-PACT-SBNR） was developed to enhance total nitrogen （TN） removal for anaerobically treated coal gasification wastewater with less need for external carbon resources. The TN removal efficiency in SBNR was significantly improved by introducing the effluent from the GAC process into SBNR during the anoxic stage, with removal percentage increasing from 43.8%49.6% to 68.8%-75.8%. However, the TN removal rate decreased with the progressive deterioration of GAC adsorption. After adding activated sludge to the GAG compartment, the granular carbon had a longer service-life and the demand for external carbon resources became lower. Eventually, the TN removal rate in SBNR was almost constant at approx. 43.3%, as compared to approx. 20.0% before seeding with sludge. In addition, the production of some alkalinity during the denitrification resulted in a net savings in alkalinity requirements for the nitrification reaction and refractory chemical oxygen demand （COD） degradation by autotrophic bacteria in SBNR under oxic conditions. PACT showed excellent resilience to increasing organic loadings. The microbial community analysis revealed that the PACT had a greater variety of bacterial taxons and the dominant species associated with the three compartments were in good agreement with the removal of typical pollutants. The study demonstrated that pre-adsorption by the GAC-sludge process could be a technically and economically feasible method to enhance TN removal in coal gasification wastewater （CGW）.     

双甘膦废水处理技术研究

双甘膦废水中含有高浓度总磷、有机磷、甲醛、氰化物、氨氮、COD,运用三效蒸发＋强氧化＋两级化学除磷＋UASB＋兼氧＋好氧组合处理双甘膦废水。研究结果表明双甘膦废水排放满足《污水综合排放标准》（G88978—1996）二级排放标准。