一种新型的生物除污菌——耐放射异常球菌

耐放射异常球菌是已知的最耐放射性的生物。该菌对DNA损伤因素 ,特别是电离辐射损伤的致死和诱变作用具有很强的抵抗力。近年来 ,随着分子生物学技术的发展 ,生物工程型的耐放射异常球菌已用于放射性环境中的金属和有机污染物的生物除污。本文对该菌的生物学特征。

养殖网箱周边的掌状红皮藻和糖海带的养殖、产出和生物除污潜力

就网箱附近养殖海藻用作吸收因投饲及鱼类排泄物而在网箱周围产生的营养物的一种方法进行了调研。发现在临近网箱处养殖的掌状红皮藻和糖海带其生长和产出均有增强。靠近网箱的巨藻其氮含量高于生长在远离网箱的巨藻的氮含量。

污水处理新途径——微生物除污

人们对于工业废水中某些特殊的有害物质，如酚、氰、塑料等高分子化合物，用物理或化学方法处理往往达不到净化的要求。为此，科学家们经过努力，终于找到了处理污水的新途径——微生物除污。

芳香族污染区的生物修复和监测研究的进展

生物除污可以修复被污染的土壤,这是因为微生物对有害有机化合物具有广泛的生物降解能力。生物除污及其功效方面研究的飞速发展,为检测各种微生物过程中相关关键基因的存在和表达提供了有效的分子学工具。综合分析被污染土壤中的各种基因在不同条件下的表达情况,揭示微生物的代谢情况,指示加速生物除污的环境变异。

生物降解与生物除污

人们越来越认识到微生物的新陈代谢能力及其与有机和无机物质的相互作用可以用来处理有害的土壤污染。本书是一本与微生物和生物化学过程相关的专著，强调了微生物在生物处理法中的用途，包括生物除污与植物除污技术的应用。

生物催化在环保中的应用进展

主要对生物催化剂在环境保护中的应用进行了阐述。具体描述了生物除污和生物产能2个方面。其中,前者包括微生物的除污和酶生物除污,后者包括生物柴油、生物乙醇、生物氢和生物燃料电池的生产。

美国廿一世纪生物技术透视

美国副总统Al Gore和总统科学顾问Dr Jack Gibbons最近宣布,一篇题为《21世纪的生物技术:新眼界》的报告已经发表。这篇90页的报告是由国家科学技术委员会下属的生物技术研究小组委员会(BRS)撰写的。Gore说:“该报告是国家科学技术委员会计划与协调的产物,目的是为今后的研究投资创造优先条件,

生物催化在环保中的应用进展

对生物催化剂在环境保护中的应用进行了阐述。具体描述了生物除污和生物产能两个方面。其中前者包括微生物的生物除污和酶生物除污,后者包括生产生物柴油、生物乙醇、生物氢和生物燃料电池。

环境生物技术

在建立持续经济增长的基础及解决很多突出的环境问题方面,生物技术将扮演一个主要角色.在这个潜力巨大的市场,要把理论知识转变为解决实际问题的方法,仍然需要强化对生物技术的研究和开发.经济合作和发展组织最近一篇报告的编者和作者之——迈克·格里菲斯博士说:“

用植物清除土壤的重金属污染

科学家研究发现,目前,大约有400种植物,可以用来清除土壤中的重金属污染。 美国佛罗里达大学的马乐娜博士指出,很多地方的土壤受到工业、矿业和农药的污染,含有会致癌的重金属砷。有一种羊齿植物,可以很有效地将土壤中的砷吸走,并将砷贮藏在它的叶和茎内。这样。

Removal of Di-n-butyl Phthalate Using Immobilized Microbial Cells

The biodegradation of di-n-butyl phthalate （DBP） using immobilized microbial cells was carded out in an internal airlift loop reactor with ceramic honeycomb supports. A strain that is capable of degrading DBP was isolated from the activated sludge and identified as Bacillus sp. using 16S rDNA sequential analysis. Bacillus sp. could be rapidly attached onto the ceramic honeycomb supports. The immobilized cells could effectively degrade DBP in batch and continuous experiments. When the influent concentration of DBP was 50mg·L^-1, the effluent DBP reached less than lmg.L i with 6h hydraulic retention time （HRT） in continuous experiment. The immobilized microbial cells could grow and accumulate through the biodegradation of DBP, and the rate of degradation is accordingly increased. The possible pathway of DBP biodegradation using immobilized cells was tentatively proposed.

Characterization of a Strain Capable of Degrading a Herbicide Mixture of Quinclorac and Bensulfuronmethyl

A bacterial strain,designated as LS,was isolated from a contaminated soil and was found to be capable of utilizing quinclorac,bensulfuronmethyl,and a mixture of the two as carbon and energy sources for growth. Strain LS was identified as Ochrobactrum sp. based on its physiological-biochemical properties,16S rDNA sequences,and phylogenetic analysis. The extent of degradation of quinclorac and bensulfuronmethyl at initial concentrations of 1.5 and 0.1 g L-1 was 90% and 67%,respectively,as measured by high performance liquid chromatography(HPLC) . When a herbicide mixture of 0.34 g L-1 quinclorac and 0.02 g L-1 bensulfuronmethyl was applied as carbon sources,quinclorac and bensulfuronmethyl were degraded at 95.7% and 67.5%,respectively. It appears that quinclorac is utilized more easily in a mixture than in a single state. The optimal temperature for growth of strain LS was 37 ℃. Strain LS grew well at pH 6 to 9 and had the highest degradation level for quinclorac and bensulfuronmethyl at an initial pH of 7 and 8,respectively. Addition of 0.25 g L-1 yeast extract could promote the growth and extent of degradation of quinclorac and bensulfuronmethyl by strain LS. Strain LS also showed the capability to degrade other aromatic compounds such as catechol,propisochlor,4-chloro-2-methylphenoxyacetic acid sodium(MCPA-Na) and imazethapy. The isolate LS shows a huge potential to be used in bioremediation for treating complex herbicide residues.

Effect of Ferric Chloride on the Properties of Biological Sludge in Co-precipitation Phosphorus Removal Process

This paper studied the effect of ferric chloride on waste sludge digestion,dewatering and sedimentation under the optimized doses in co-precipitation phosphorus removal process.The experimental results showed that the concentration of mixed liquid suspended solid(MLSS) was 2436 mg.L-1 and 2385 mg.L-1 in co-precipitation phosphorus removal process(CPR) and biological phosphorous removal process(BPR),respectively.The sludge reduction ratio for each process was 22.6% and 24.6% in aerobic digestion,and 27.6% and 29.9% in anaerobic digestion,respectively.Due to the addition of chemical to the end of aeration tank,the sludge content of CPR was slightly higher than that of BPR,but the sludge reduction rate for both processes had no distinct difference.The sludge volume index(SVI) and sludge specific resistance of BPR were 126 ml.g-1 and 11.7×1012 m.kg-1,respectively,while those of CPR were only 98 ml.g-1 and 7.1×1012 m.kg-1,indicating that CPR chemical could improve sludge settling and dewatering.

Effect of Return Sludge Pre-concentration on Biological Phosphorus Removal in a Novel Oxidation Ditch

A pilot-scale,pre-anoxic-anaerobic oxidation ditch was used in this study to treat municipal wastewater with limited carbon source.A novel return activated sludge(RAS) pre-concentration tank was adopted for improv-ing the phosphorus removal efficiency and the effects of RAS pre-concentration ratio were studied.Under the opti-mal operational condition,the suspended total phosphorus(STP) and the total phosphorus(TP) removal efficiencies were around 58.9% and 63.9% respectively and the effluent-P was lower than 0.8 mg·L-1.The reason is that with the optimal RAS pre-concentration ratio,nitrate is completely removed with endogenous carbon source and the secondary phosphorus release is strictly restrained in the pre-anoxic tank.Therefore,the anaerobic phosphorus release and the carbon source uptake by phosphorus accumulation organisms(PAOs) in the sludge,which are ex-tremely important to the phosphorus removal process,can be fully satisfied.Furthermore,the oxidation-reduction potential is proved to be suitable for controlling the RAS pre-concentration ratio due to influent fluctuation and varied conditions.The novel modified system is also beneficial for PAO accumulation.

Enhanced Biological Phosphorus Removal with Pseudomonas putida GM6 from Activated Sludge

The enhanced biological phosphorus removal （EBPR） method is widely adopted for phosphorus removal from wastewater, yet little is known about its microbiological and molecular mechanisms. Therefore, it is difficult to predict and control the deterioration of the EBPR process in a large-scale municipal sewage treatment plant. This study used a novel strain isolated in the laboratory, Pseudomonas putida GM6, which had a high phosphate accumulating ability and could recover rapidly from the deteriorated system and enhance the capability of phosphorus removal in activated sludge. Strain GM6 marked with gfp gene, which was called GMTR, was delivered into a bench-scale sequencing batch reactor （SBR） of low efficiency, to investigate the colonization of GMTR and removal of phosphorus. After 21 days, the proportion of GMTR in the total bacteria of the sludge reached 9.2%, whereas the phosphorus removal rate was 96%, with an effluent concentration of about 0.2 mg L^-1. In the reactor with the addition of GMTR, phosphorus was removed quickly, in 1 h under anaerobic conditions, and in 2 h under aerobic conditions. These evidences were characteristic of EBPR processes. Field testing was conducted at a hospital sewage treatment facility with low phosphorus removal capability. Twentyone days after Pseudomonas putida GM6 was added, effluent phosphorus concentration remained around 0.3 mg L^-1, corresponding to a removal rate of 96.8%. It was therefore demonstrated that Pseudomonas putida GM6 could be used for a quick startup and enhancement of wastewater biological phosphorus removal, which provided a scientific basis for potential large-scale engineering application.

Biological Nutrient Removal in a Full Scale Anoxic/Anaerobic/Aerobic/ Pre-anoxic-MBR Plant for Low C/N Ratio Municipal Wastewater Treatment

A novel full scale modified A2O （anoxic/anaerobic/aerobic/pre-anoxic）-membrane bioreactor （MBR） plant combined with the step feed strategy was operated to improve the biological nutrient removal （BNR） from low C/N ratio municipal wastewater in Southern China. Transformation of organic carbon, nitrogen and phosphorus, and membrane fouling were investigated. Experimental results for over four months demonstrated good efficiencies for chemical oxygen demand （COD） and NH4^＋-N removal, with average values higher than 84.5%and 98.1%, re-spectively. A relatively higher total nitrogen （TN） removal efficiency （52.1%） was also obtained at low C/N ratio of 3.82, contributed by the configuration modification （anoxic zone before anaerobic zone） and the step feed with a distribution ratio of 1：1. Addition of sodium acetate into the anoxic zone as the external carbon source, with a theoretical amount of 31.3 mg COD per liter in influent, enhanced denitrification and the TN removal efficiency in-creased to 74.9%. Moreover, the total phosphate （TP） removal efficiency increased by 18.0%. It is suggested that the external carbon source is needed to improve the BNR performance in treating low C/N ratio municipal waste-water in the modified A^2O-MBR process.

Enhanced biological nutrient removal in modified carbon source division anaerobic anoxic oxic process with return activated sludge pre-concentration

A pilot-scale modified carbon source division anaerobic anoxic oxic(AAO) process with pre-concentration of returned activated sludge(RAS) was proposed in this study for the enhanced biological nutrient removal(BNR) of municipal wastewater with limited carbon source. The influent carbon source was fed in step while a novel RAS pre-concentration tank was adopted to improve BNR efficiency, and the effects of an influent carbon source distribution ratio and a RAS pre-concentration ratio were investigated. The results show that the removal efficiency of TN is mainly influenced by the carbon source distribution ratio while the TP removal relies on the RAS pre-concentration ratio. The optimum carbon source distribution ratio and RAS pre-concentration ratio are 60% and 50%, respectively, with an inner recycling ratio of 100% under the optimum steady operation of pilot test, reaching an average effluent TN concentration of 9.8 mg·L-1with a removal efficiency of 63% and an average TP removal efficiency of 94%. The mechanism of nutrient removal is discussed and the kinetics is analyzed. The results reveal that the optimal carbon source distribution ratio provides sufficient denitrifying carbon source to each anoxic phase, reducing nitrate accumulation while the RAS pre-concentration ratio improves the condition of anaerobic zone to ensure the phosphorus release due to less nitrate in the returned sludge. Therefore, nitrifying bacteria, denitrifying bacteria and phosphorus accumulation organisms play an important role under the optimum condition, enhancing the performance of nutrient removal in this test.

Study on Algae Removal by Immobilized Biosystem on Sponge

In this study, sponges were used to immobilize domesticated sludge microbes in a limited space, forming an immobilized biosystem capable of algae and microcystins removal. The removal effects on algae, microcystins and UV 260 of this biosystem and the mechanism of algae removal were studied. The results showed that active sludge from sewage treatment plants was able to remove algae from a eutrophic lake’s water after 7 d of domestication. The removal efficiency for algae, organic matter and microcystins increased when the domesticated sludge was immobilized on sponges. When the hydraulic retention time (HRT) was 5 h, the removal rates of algae, microcystins and UV 260 were 90%, 94.17% and 84%, respectively.The immobilized biosystem consisted mostly of bacteria, the Ciliata and Sarcodina protozoans and the Rotifer metazoans. Algal decomposition by zoogloea bacteria and preying by microcreatures were the two main modes of algal removal, which occurred in two steps: first, absorption by the zoogloea; second, decomposition by the zoogloea bacteria and the predacity of the microcreatures.

Biological treatment of high NH_4^+-N wastewater using an ammonia-tolerant photosynthetic bacteria strain (ISASWR2014)

Wastewater with high NH_4^+-N is difficult to treat by traditional methods.So in this paper,a wild strain of photosynthetic bacteria was used for high NH_4^+-N wastewater treatment together with biomass recovery.Isolation,identification,and characterization of the microorganism were carried out.The strain was inoculated to the biological wastewater treatment unit.The impacts of important factors were examined,including temperature,dissolved oxygen,and light intensity.Results showed that photosynthetic bacteria could effectively treat high NH_4^+-N wastewater.For wastewater with NH_4^+-N of 2300 mg·L^(-1),COD/N=1.0,98.3%of COD was removed,and cell concentration increased by 43 times.The optimal conditions for the strain's cell growth and wastewater treatment were 30℃,dissolved oxygen of 0.5-1.5 mg·L^(-1) and a light intensity of 4000 lx.Photosynthetic bacteria could bear a lower C/N ratio than bacteria in a traditional wastewater treatment process,but the NH_4^+-N removal was only 20%-40%because small molecule carbon source was used prior to NH_4^+-N.Also,the use of photosynthetic bacteria in chicken manure wastewater containing NH4+-N about 7000 mg·L^(-1) proved that photosynthetic bacteria could remove NH_4^+-N in a real case,finally,83.2%of NH_4^+-N was removed and 66.3%of COD was removed.