Biological nitrogen removal with enhanced phosphate uptake in (AO)2 SBR using single sludge system

IntroductionBiologicalphosphorusandnitrogenremovalprocesshasprovidedsignificantbenefitstoameliorateeutrophicationofsurfacewaterwithoutexacerbatingsalination .Recentresearchesonnitrogenremovalaremostlyeithertowardsimprovementofperformanceandenergysavingsintraditionalprocessesortowardsdevelopmentofnewprocesses microorganismsthatareabletoconvertammonium oxidatednitrogenintoharmlessforms.Shorternitrificationanddenitrification ,i.e .partialoxidationofNH 4toNO-2 andsubsequentreductionofthelatterto…     

A methodological approach to develop “contaminant migration–population effects” models

The main aim of the present work is to discuss the methodological approaches that underpin the “contaminant migration–population effects” models for the evaluation of the detriment to populations of moving organisms in environmental systems with spatial and time dependent pollution levels. A technique to couple the equations controlling the population dynamics and the pollutant dispersion is described and discussed. The domain of application and the limitations of the methodology are analysed and illustrated by some examples. Possible alternative approaches are briefly presented.     

不同碳源条件下聚磷菌代谢特性

利用2套SBR系统在厌氧好氧交替条件下对聚磷菌(phosphorus accumulating organisms,PAO)进行富集,分别采用乙酸和丙酸作为碳源。通过对典型周期内磷酸盐,聚羟基烷酸(polyhydroxyalkanoates,PHAs),糖原和多聚磷酸盐变化情况的分析,探讨了不同碳源下,聚磷菌胞内碳源物质的代谢机理以及其对于生物除磷的影响。结果表明,以乙酸为碳源时,PHAs的合成量和分解量都要高于丙酸为碳源,且PHAs主要成分以聚-β-羟丁酸(poly-β-hydroxybutyrate,PHB)为主,污泥的比释磷速率和比吸磷速率都要高于丙酸为碳源的情况。     

碳源对反硝化除磷效能及N_2O产生的长期影响

基于碳源对反硝化除磷效能以及N2O产生机制尚未明确的现状,采用厌氧/缺氧/好氧序批式反应器(An/A/O-SBR),考察了碳源(乙酸、丙酸和两者的混合酸(摩尔比为1∶1))对反硝化除磷效能和污泥形态的长期影响。结果发现,混合酸系统脱氮除磷效果最稳定,氮和磷平均去除率分别为67.7%和87.0%;而乙酸和丙酸系统较不稳定,氮和磷平均去除率分别为97.6%、51.0%和41.9%、100.0%。混合酸系统检测到明显的N2O释放,而乙酸和丙酸系统的N2O产率较低。     

改良型A2/O-MBR工艺的反硝化除磷性能研究简

重点考察了一种改良型膜生物反应器（A²/O-MBR）的脱氮除磷性能。该工艺主要特点在于对膜池硝化回流液进行了固液分离,并将上清液和浓缩污泥分别回流至缺氧池和厌氧池,这种改进提高了系统对氮、磷的同步去除效率。实验结果表明,在水力停留时间（HRT）为12 h,污泥龄（SRT）为30 d,混合液回流比为200%的运行条件下,进水COD、NH₄⁺-N、TN和TP平均浓度分别为（225±38）、（24.8±3.9）、（26.7±2.9）和（2.90±0.53）mg/L时,增加膜池硝化回流液固液分离装置前后,系统对COD和NH₄⁺-N的去除都维持在较高水平,而系统对TN和TP的去除效果显著提高,出水TN和TP平均浓度分别由（14.9±3.3）mg/L和（1.95±0.72）mg/L下降到（9.4± 1.9）mg/L和（0.91±0.38）mg/L,表明增加膜池硝化回流液固液分离装置显著改善了A²/O-MBR系统的脱氮除磷效果。反硝化除磷活性实验结果进一步表明,改进后系统中反硝化除磷活性占总除磷活性的比例由51.5%上升至61.7%,说明增加膜池硝化回流液固液分离装置强化了系统的反硝化除磷性能。     

拟柱孢藻毒素生态毒性的研究进展和展望

随着全球变暖的加剧,拉氏拟柱胞藻(Cylindrospermopsis raciborskii)表现出从热带和亚热带地区向温带地区迁移和扩张的趋势。拟柱孢藻过度繁殖引发的主要生态环境问题是其有毒次级代谢产物——拟柱孢藻毒素(cylindrospermopsin,CYN)的大量产生。这种蓝藻毒素水溶性很高,可长时间停留在水体中,对动植物和人类健康造成威胁。近年来,国际上对CYN的研究越来越多,研究范围也日趋广泛,而国内的相关研究却很少。本文根据现有的研究结果,介绍了CYN的分子结构和理化特性;总结了CYN可能对水生生物、土壤作物和人类健康造成的影响和危害,并对相应的致毒机理进行了归纳总结;最后对未来的研究内容和方向进行了展望。     

反硝化除磷颗粒污泥的活性恢复及对生活污水处理能力

实验利用序批式反应器(SBR)考察反硝化除磷颗粒污泥搁置1个月后重新投入运行,其活性恢复能力及对实际生活污水的处理效果。结果表明,颗粒污泥搁置后外观由淡黄色转变为灰黑色,颗粒重新投入反应器,11 d后颜色基本恢复,污泥浓度及活性迅速增加;对COD处理能力的恢复历时14 d,去除率稳定在80.32%以上;颗粒污泥对NH4+-N和PO34--P的去除在40 d时也恢复到正常水平;反硝化聚磷菌(DNPAOs)活性恢复期为50 d。颗粒污泥对低碳氮比的实际生活污水处理结果显示,当C/N<5.1时(生活污水比例>60%),无法满足系统内微生物生长要求,需要外加适量碳源进行补充。     

Illicit drugs as new environmental pollutants: cyto-genotoxic effects of cocaine on the biological model Dreissena polymorpha

The increase in global consumption of illicit drugs has produced not only social and medical problems but also a potential new environmental danger. Indeed, it has been established that drugs consumed by humans end up in surface waters, after being carried through the sewage system. Although many studies to measure concentrations of several drugs of abuse in freshwater worldwide have been conducted, no data have been available to evaluate their potentially harmful effects on non-target organisms until now. The present study represents the first attempt to investigate the cyto-genotoxic effects of cocaine, one of the primary drugs consumed in Western Countries, in the biological model Dreissena polymorpha by the use of a biomarker battery. We performed the following tests on Zebra mussel hemocytes: the single cell gel electrophoresis (SCGE) assay, the apoptosis frequency evaluation and the micronucleus assay (MN test) for the evaluation of genotoxicity and the lysosomal membranes stability test (neutral red retention assay; NRRA) to identify the cocaine cytotoxicity. We exposed the molluscs for 96 h to three different nominal concentrations in water (40 ng L⁻¹; 220 ng L⁻¹; and 10 μg L⁻¹).Cocaine caused significant (p < 0.05) primary DNA damage in this short-term experiment, but it also caused a clear increase in micronucleated cells and a marked rise in apoptosis, which was evident in samples from even the lowest environmental cocaine concentration. Because cocaine decreased the stability of lysosomal membranes, we also highlighted its cytotoxicity and the possible implications of oxidative stress for the observed genotoxic effects.     

Effects of red‐headed pine sawfly,Neodiprion lecontei,nuclear polyhedrosis virus on rainbow trout,Salmo gairdneri,and Daphnia pulex

Abstract

The effects of a nuclear polyhedrosis virus (NPV) of the red‐headed pine sawfly, Neodiprion lecontei, on rainbow trout, Salmo gairdnevi, were investigated. The fish were exposed to this virus by intubation and topical application and no ill‐effects were observed. Similarly, no ill‐effects were detected in Daphnia pulex when the same NPV was added to their culture medium. The materials were lyophilized, NPV‐infected sawfly larvae (normally used for insect control), lyophilized, unin‐fected larvae and purified, polyhedral inclusion bodies. On the basis of these laboratory tests, this virus, when disseminated as a biocontrol agent, should present no hazard to rainbow trout or to the aquatic invertebrate Daphnia pulex, two species frequently used in toxicity tests of chemical pesticides.     

Mercury in the biotic compartments of Northwest Patagonia lakes, Argentina

We report on total mercury (THg) concentrations in the principal components of food webs of selected Northern Patagonia Andean Range ultraoligotrophic lakes, Argentina. The THg contents were determined using Instrumental Neutron Activation Analysis in muscle and liver of four fish species occupying the higher trophic positions (the introduced Salmo trutta, Oncorhynchus mykiss and Salvelinus fontinalis, and the native Percichthys trucha) accounted for eight lakes belonging to Nahuel Huapi and Los Alerces National Parks. We studied the food web components of both the West and East branches of Lake Moreno, including benthic primary producers such as biofilm, mosses, and macrophytes, three plankton fractions, fish, riparian tree leaves, and benthic invertebrates, namely decapods, molluscs, insect larvae, leeches, oligochaetes, and amphipods.Mercury concentrations in fish muscle varied in a wide range, from less than 0.05 to 4 μg g⁻¹ dry weight (DW), without a distribution pattern among species but showing higher values for P. trucha and S. fontinalis, particularly in Lake Moreno.The THg contents of the food web components of Lake Moreno varied within 4 orders of magnitude, with the lower values ranging from 0.01 to 0.5 μg g⁻¹ DW in tree leaves, some macrophytes, juvenile salmonids or benthic macroinvertebrates, and reaching concentrations over 200 μg g⁻¹ DW in the plankton. Juvenile Galaxias maculatus caught in the pelagic area presented the highest THg contents of all fish sampled, reaching 10 μg g⁻¹ DW, contents that could be associated with the high THg concentrations in plankton since it is their main food source. Although Lake Moreno is a system without local point sources of contamination, situated in a protected area, some benthic organisms presented high THg contents when compared with those from polluted ecosystems.