新型碳源驯化的SRB去除酸性矿山废水中SO_4~(2-)最佳反应条件

针对硫酸盐还原菌(SRB)处理酸性矿山废水缺乏有效有机碳源问题,运用生活污水、鸡粪和锯末质量比80∶7∶3混合物的发酵液作为新型有机碳源驯化硫酸盐还原菌SRB,并研究SRB以该新型有机碳源作为营养物质在不同COD/SO2-4(C/S)值、pH值、初始硫酸根(SO2-4)浓度、重金属离子(Fe2+、Mn2+、Cu2+和Zn2+)浓度条件下对SO2-4的去除效果,以确定SRB去除SO2-4的最佳反应条件。实验结果表明,在厌氧环境SRB接种量8%、生长温度35℃、转速50 r/min、C/S为1.5~2.0、pH值6~7、初始SO2-4浓度≤3 000 mg/L、Fe2+在100~300 mg/L、Mn2+为35 mg/L时反应条件最佳,SO2-4去除率均可达90%以上;其中Fe2+浓度≤500 mg/L、Mn2+浓度≤140 mg/L时均会促进SRB对SO2-4的还原,当Fe2+浓度≥600mg/L时会严重抑制SRB,Mn2+浓度140 mg/L时会抑制SRB;Cu2+、Zn2+的存在对SRB均有影响,当Cu2+浓度15 mg/L时、Zn2+浓度45 mg/L时对SRB均有抑制作用。新型有机碳源可作为SRB的优良有机碳源,同时可实现以废治废的目的。该成果为实际应用提供了参考。     

生物质碳源组合型生态浮床系统脱氮效果研究

利用农业废弃物和水生植物,结合水下空间与水面景观,构建集成脱氮技术的新型立体组合式生态浮床系统用以地表水体中氮的脱除以净化水质。立体生态浮床运行2个月之后的结果显示,NH3-N、TN和CODMn的去除率可分别达到96.77%、95.51%和77.75%,本浮床具有较高脱氮能力,水体净化效果明显;同时,整个生态浮床系统的生物多样性较为丰富,原水分别为Ⅴ类和劣Ⅴ类的池2和池5中分别鉴定出6种和8种主要氨氧化菌谱带,位于系统中部的玉米芯和稻草表面微生物多样性丰富程度较高;稻草和底泥中氨氧化菌的谱带种类最多。与池2相比,池5中除了存在共有谱带外,还存在特有谱带h和j带,表明可能有特殊氨氧化菌群的存在。本组合型生态浮床具有同步硝化与反硝化作用,利于沉水植物生长,并能促进水生态系统构建。     

包埋氨氧化细菌处理合成氨工业废水

以聚乙烯醇与海藻酸钠为载体,包埋固定氨氧化细菌(AOB),研究温度、DO、初始游离氨(FA)、有机物等影响因素对其短程硝化稳定性的影响。结果表明,25~30℃时载体中氨氧化细菌占优势;DO宜控制在4.0~5.5 mg/L之间,既能满足细菌生长所需,又不至过度曝气,造成载体间的摩擦增大,减少其使用寿命;载体耐氨氮负荷能力强,同时可以抵御有机物对氨氧化细菌的伤害;当初始FA>6.5 mg/L时,氨氧化细菌的活性将受到抑制;富集氨氧化细菌的污泥包埋后氨氮去除率降低了7.5%;包埋载体在确保短程硝化作用的同时,在内部形成的缺氧区可实现反硝化脱氮,提高了系统氨氮的处理能力。     

降解SO_2功能菌的16S rRAN基因测序及降解特性

用低浓度SO2诱导驯化方法获得高效脱硫菌群,并用分离培养与16S rRNA基因测序技术相结合的方法鉴定菌群种属,分析驯化过程中种群结构的动态变化,同时研究分离纯菌种的脱硫性能。结果表明,从诱导驯化7 d和14 d菌液中分别分离出23株菌和22株菌,16S rRNA序列分析发现这些菌归属于13个种,其中有6个种（Rhodococcus erythropolis、Pseudomonas putida、Microbacterium oxydans、Sphingomonas koreensis、Acinetobacter junii、Acinetobacter johnsonii）对SO2-3有较强的降解能力,并在持续驯化过程中稳定的生长传代,降解产物以硫酸根为主,还有极少量的单质硫。与含混合菌的驯化菌液降解SO2-3的能力相比,单一脱硫菌的脱硫性能较弱。脱硫功能菌株及其基本特性的研究为微生物处理SO2烟气提供了丰富的菌源信息和理论基础。     

MnO_2对海底沉积物ANAMMOX菌的富集培养影响

采用上流式固定床反应器,在常温下连续运行,考察MnO2对海洋性ANAMMOX菌富集培养的影响,其中接种的海洋海底沉积物采自大连市附近海域。结果表明,在反应器运行近150 d中,加入MnO2的R1反应器的最大总氮去除速率为137.82 g N/(m3·d),比没有加入MnO2的R2反应器高出近20 g N/(m3·d)。在低温环境(10~15℃)运行时,R1反应器的氨氮和亚硝氮去除率比R2反应器均高出10%,且R1反应器对温度变化的适应性和运行稳定性都好于R2反应器。这表明MnO2的加入确实在一定程度上促进了海洋性ANAMMOX细菌的富集,并增强了ANAMMOX反应器对温度变化的适应性,使其能够在较宽的温度范围下运行。     

Effects of growth substrate on triclosan biodegradation potential of oxygenase-expressing bacteria

Triclosan is an antimicrobial agent, an endocrine disrupting compound, and an emerging contaminant in the environment. This is the first study investigating triclosan biodegradation potential of four oxygenase-expressing bacteria: Rhodococcus jostii RHA1, Mycobacterium vaccae JOB5, Rhodococcus ruber ENV425, and Burkholderia xenovorans LB400. B. xenovorans LB400 and R. ruber ENV425 were unable to degrade triclosan. Propane-grown M. vaccae JOB5 can completely degrade triclosan (5 mg L⁻¹). R. jostii RHA1 grown on biphenyl, propane, and LB medium with dicyclopropylketone (DCPK), an alkane monooxygenase inducer, was able to degrade the added triclosan (5 mg L⁻¹) to different extents. Incomplete degradation of triclosan by RHA1 is probably due to triclosan product toxicity. The highest triclosan transformation capacity (T_c, defined as the amount of triclosan degraded/the number of cells inactivated; 5.63 × 10⁻³ ng triclosan/16S rRNA gene copies) was observed for biphenyl-grown RHA1 and the lowest T_c (0.20 × 10⁻³ ng-triclosan/16S rRNA gene copies) was observed for propane-grown RHA1. No triclosan degradation metabolites were detected during triclosan degradation by propane- and LB + DCPK-grown RHA1. When using biphenyl-grown RHA1 for degradation, four chlorinated metabolites (2,4-dichlorophenol, monohydroxy-triclosan, dihydroxy-triclosan, and 2-chlorohydroquinone (a new triclosan metabolite)) were detected. Based on the detected metabolites, a meta-cleavage pathway was proposed for triclosan degradation.     

拮抗菌对黄瓜枯萎病菌的室内生物活性

测定了从沤肥浸渍液和土壤中分离并筛选得到对黄瓜枯萎病菌的室内生物活性的6个菌株,编号为94－I、94－Ⅱ、94－Ⅲ、96－Ⅰ和98－Ⅱ,测定其孢子悬浮培养16h时对黄瓜枯萎菌的抑制率分别为48．29％、0．00％、60．69％、39．28％、61．29％和72．32％,孢子和菌丝有的变畸形并产生大泡囊;平皿拮抗试验表明,其活体浓度为50％时对黄瓜枯萎病菌的抑制率最大分别为74．52％、83．27％、90．60％、88．59％、89．35％和94．30％;而其相同浓度高压蒸汽灭活后的代谢产物对黄瓜枯萎病菌的抑制率最大分别为33．215、52．22％、62．84％、46．57％、47．61％和70．34％。     

Sociological dimension in the handling habit and sanitary quality of hand-dug well water from oil-producing area of Nigeria

A previous report showed that the physical and sanitary quality of hand-dug wells from an oil-producing area of Nigeria was poor in spite of the presence of well protective features. The hypothesis that handling habits is associated with the well water quality was therefore, tested. A structured questionnaire with scales for measuring handling habits was administered to 60 female (>18 years) hand-dug well users/owners randomly selected from three towns in the oil-producing area. The respondents’ wells were analysed for coliform bacteria. The findings showed that poor handling habits were the trend (habit score: Mean, 9.23 vs. 20 total available points). Handling habit indicated by scores, significantly negatively correlated (−0.89; P < 0.01) with coliform counts (indicator of poor sanitary quality). While the data collected and discussions with respondents indicated awareness of the risk of drinking well water, widespread skepticism of the potential hazards of non-drinking domestic uses (e.g., cooking, washing of plates, cups, cutleries etc.) was evident. Discontent with some aspects of science was indicated. It is concluded that there is need for social discourse and more public health campaign aimed at transforming skepticism to consent.     

Monitoring of Aerial Pollutants Emitted from Swine Houses in Korea

This on-site survey study was performed to determine the concentrations and emissions of aerial contaminants in the different types of swine houses in Korea and then to present beneficial information available for Korean pig producers to manage optimal air quality in swine house. The swine houses investigated in this research were selected based on three criteria; manure removal system, ventilation mode and growth stage of swine. Mean concentrations of aerial pollutants in swine houses were 8 ppm for ammonia, 300 ppb for hydrogen sulfide, 2 mg m⁻³ for total dust, 0.6 mg m⁻³ for respirable dust, 4 log(cfu m⁻³) for total airborne bacteria and 3 log(cfu m⁻³) for total airborne fungi, respectively. Mean emissions based on pig (liveweight; 75 kg) and area (m²) were 250 and 340 mg h⁻¹ for ammonia, 40 and 50 mg h⁻¹ for hydrogen sulfide, 40 and 50 mg h⁻¹ for total dust, 10 and 15 mg h⁻¹ for respirable dust, 1.0 and 1.3 log(cfu) h⁻¹ for total airborne bacteria and 0.7 and 1.0 log(cfu) h⁻¹ for total airborne fungi, respectively. In general concentrations and emissions of gases were relatively higher in the swine houses managed with deep-pit manure system with slats and mechanical ventilation mode than the different swine housing types whereas those of particulates and bioaerosol were highest in the naturally ventilated swine houses with deep-litter bed system.