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1.
微生物絮凝剂具有无毒性,绿色生产等优点,能够安全地用于给水处理及污废水处理.本文通过阳离子改性和与非生物絮凝剂复配的方法,提高MBF-NIII2的絮凝能力.以MBF-NIII2为原料,利用3-氯-2-羟丙基三甲基氯化铵(CHTAC)对其修饰,合成新型阳离子化的微生物絮凝剂(CMBF-NIII2)以CMBF-NIII2为研究主要对象,对校园生活污水进行处理.通过改变投加量、pH值、沉淀时间与温度,探究CMBF-NIII2絮凝能力的变化规律.将改性前的MBF-NIII2与改性后的CMBF-NIII2分别用于校园生活废水的处理,对比发现当CMBF-NIII2投加量为1.3 mL,pH 4.6,温度为60℃,沉降时间为40 min时,絮凝率达到91.5%,且COD去除率为87.8%,絮凝能力明显优于MBF-NIII2(絮凝率为47.61%),能更高效地絮凝生活污水.以MBF-NIII2与三氯化铁复配处理生活污水,结果表明MBF-NIII2和FeCl_3的投加量分别为10 mg·L~(-1)和15 mg·L~(-1)时,絮凝率可达88.06%,不仅比单独使用MBF-NIII2的处理效果好,还相对减少了絮凝剂的投加量.  相似文献   

2.
一株产生物絮凝剂的Bacillus sp.的分离与鉴定   总被引:2,自引:0,他引:2  
从重庆城南污水处理厂的活性污泥中分离筛选到一株絮凝剂产生菌,革兰氏染色呈阳性,好氧,有芽孢,可运动,短杆;分离菌的基因组DNA(G +C)mol%含量测定为5 0 .6 % ,16SrRNA序列分析表明,分离筛选出的絮凝剂产生菌的16SrRNA基因序列与Bacillus菌有高度同源性,从而确定絮凝剂产生菌RL - 2归于Bacillusbrevis菌属。絮凝实验表明:在有CaCl2 存在时用Bacillussp .RL - 2生物絮凝剂处理土壤悬液时用量少(10 0mL样品只需2mL絮凝剂) ,絮体形成快,矾花大,泥少;体系温度对活性影响很小,且在酸性与碱性条件下,絮凝活性均很高  相似文献   

3.
刘桂萍  王明杰  刘长风 《生态环境》2010,19(10):2479-2483
利用壳聚糖/钠基膨润土复合絮凝剂对活性艳红X3B等11种染料模拟废水及实际印染废水进行絮凝脱色处理。考察了复合絮凝剂投加量、pH值、搅拌速率、搅拌时间等因素对模拟染料废水絮凝脱色的影响。结果表明,在染料浓度为100 mg.L-1,pH为5的条件下,复合絮凝剂投加量为1.25 g.L-1时,3种质量比的复合絮凝剂对活性艳红X3B的脱色率分别达到75%、90%和97%以上;质量比为1∶10的壳聚糖/钠基膨润土复合絮凝剂,对其它活性、还原性、分散性、水溶性等8种印染厂常用染料也具有很好的絮凝脱色作用,脱色率均可达94%以上。对印染废水处理厂进水口废水和经过A/O处理后废水的色度去除率和COD去除率分别可以达到81.05%、83.74%和53.21%、41.22%,具有一定的应用前景。  相似文献   

4.
混合型微生物絮凝剂产生菌的最佳培养条件   总被引:7,自引:0,他引:7  
从活性污泥中筛选出具有较高絮凝活性的混合菌MBFH,研究了各种条件对混合菌产絮凝剂的影响.结果表明,混合菌MBFH产絮凝剂的最佳培养条件为:温度30℃、初始pH8.0、摇床转速为120r/min、培养基含糖量2%、相对接种量15%,其对高岭土悬浊液的絮凝率可达到88%.图5表4参9  相似文献   

5.
应用微絮凝过滤的污水深度处理研究   总被引:1,自引:0,他引:1  
本文就微絮凝过滤用于污水深度处理进行了研究.该工艺选用了陶粒一砂双层滤料滤池,絮凝剂选用了无机高分子絮凝剂PFC(投量20mg/L)和有机高分子絮凝剂(投量0.2mg/L);滤池的反冲洗用气一水·气一水三阶段反洗,效果良好.过滤实验的研究进行了直接过滤,单投PFC及PFC与PDM复配投加的微絮凝过滤三种方式.PFC与PDM复配对色度、COD、T—P有显著的去除效果.  相似文献   

6.
利用鱼粉废水生产生物絮凝剂及其性能研究   总被引:10,自引:0,他引:10  
研究了不同培养时间下鱼粉废水中假单胞菌(Pseudomonas sp.)GX4—1菌的生长状况、培养液pH值和絮凝活性变化,发现该絮凝剂产生于菌生长过程中的,培养基灭菌与否对菌合成絮凝剂的特性无大影响.与其它几种常用絮凝剂相比,该絮凝剂对高岭土悬液的絮凝活性较高(絮凝率达95%以上).发酵液经中速离心获得的上清液作为絮凝剂样品不仅具有良好的热稳定性,且在低温储存170d内活性稳定,对土壤悬液和大肠杆菌悬液表现出良好的絮凝能力。  相似文献   

7.
微生物絮凝剂絮凝特性的研究   总被引:19,自引:0,他引:19  
考察了微生物絮凝剂产生菌Bacillus sp.B-2发酵生产絮凝剂的絮凝特性。研究表明,该菌在生长过程中产生絮凝剂并将其分泌到细胞外,每升发酵液可制得絮凝剂粗品1.7g,絮凝活性最高达97%以上,絮凝效能优于目前市售化学絮凝剂。该絮凝剂凝聚絮凝高岭土悬浊液最适宜的pH值在大于7的偏碱性条件,Ca^2 ,Mg^2 ,Mn^2 ,Al^3 等二价、三价金属离子对其絮凝具有促进作用,且随着Ca^2 浓度的增加,促进作用加强。  相似文献   

8.
筛选出一株絮凝剂产生菌TF10,鉴定为巨大芽孢杆菌(Bacillus megaterium).以高岭土悬浊液为絮凝对象,研究了pH值、絮凝剂用量和不同阳离子对TF10产生的絮凝剂P-TF10絮凝效率的影响.结果表明,P-TF10在偏酸和微碱范围内活性较高;絮凝剂存在最佳用量,不足或过高会导致絮凝率下降;Ca2+和Al3+对絮凝的促进作用明显,而Mg2+和Na+对絮凝无作用.应用响应曲面法对P-TF10的絮凝条件进行了优化,得到最佳条件为:pH=4.7,CaCl2浓度为7.0mmol.l-1,P-TF10的用量为34.6 mg.l-1,该条件下絮凝率可达(95.5±1.0)%.  相似文献   

9.
微生物絮凝剂产生菌的筛选和优化以及在水处理中的应用   总被引:28,自引:0,他引:28  
从土壤中筛到1株絮凝剂产生菌BY-28,该菌产生的絮凝剂对高岭土悬浊液的絮凝活性较高且稳定,鉴定为多粘类芽孢杆菌Paenibacillus polymyxa BY-28.菌BY-28产絮凝剂的最佳培养基和培养条件为:葡萄糖2%,KH2PO40.4%,黄豆饼粉0.1%,MgSO4·7H2O 0.05%,CaCl2 0.05%,pH 7.0,30℃,180 r/min摇床培养2-3 d,产生具有高絮凝活性的絮凝剂.该絮凝剂对水中无机悬浮物和有机染料具有较高的去除率,尤其是能够有效地去除肌苷发酵液和肌苷生产废水中的菌体及悬浮物.图3表4参16  相似文献   

10.
研究2株霉菌利用酒精废水产絮凝剂的絮凝效果以及菌株的生长情况.结果表明:在酒精废水中添加少量营养物质可作为廉价培养基使用;确定了廉价培养基的组成,絮凝剂产量分别达到淀粉培养基产量的94.5%和92.2%;廉价培养基培养HHE-P7和HHE-A26的培养液对高岭土悬浊液、猪场废水、建材废水、餐饮废水、城市生活污水都具有良好的絮凝效果,达到淀粉培养基的92.6%~97.8%.图4表3参19  相似文献   

11.
Protected areas (PAs) are often implemented without consideration of already existing PAs, which is likely to cause an overrepresentation of certain biophysical conditions. We assessed the representativeness of the current PA network with regard to the world's biophysical conditions to highlight which conditions are underprotected and where these conditions are located. We overlaid terrestrial and marine PAs with information on biophysical conditions (e.g., temperature, precipitation, and elevation) and then quantified the percentage of area covered by the PA network. For 1 variable at a time in the terrestrial realm, high temperature, low precipitation, and medium and very high elevation were underrepresented. For the marine realm, low and medium sea surface temperature (SST), medium and high sea surface salinity (SSS), and the deep sea were underrepresented. Overall, protection was evenly distributed for elevation across the terrestrial realm and SST across the marine realm. For 2 variables at a time, cold and very dry terrestrial environments had mostly low protection, which was also the case for low SST and low and medium SSS across most depths for marine environments. Low protection occurred mostly in the Sahara and the Arabian Peninsula for the terrestrial realm and along the Tropic of Capricorn and toward the poles for the marine realm. Although biodiversity measures are of prime importance for the design of PA networks, highlighting biophysical gaps in current PAs adds a frequently overlooked perspective. These gaps may weaken the potential of PAs to conserve biodiversity. Thus, our results may provide useful insights for researchers, practitioners, and policy makers to establish a more comprehensive global PA network.  相似文献   

12.
Summary The adaptation of defensive secretions to their target organisms was examined for the abdominal gland secretions ofBledius furcatus, B. spectabilis andB. arenarius. Therefore the target organisms of the secretion of theseBledius species (i.e. their predators) had to be identified. At the collection sites examined these were the earwigLabidura riparia, the antCataglyphis bicolor, the flyLispe candicans, different carabids of the generaPogonus, Dichirotrichus, Dyschirius, Bembidion andCalathus and the wading birdsHaematopus ostralegus andCalidris alba. The secretion of the abdominal glands contains the toxin ptoluquinone dissolved in either-dodecalactone and 1-undecene (B. furcatus andB. spectabilis) or in octanoic acid and octyloctanoate (B. arenarius). The ratio of these solvents is species-specific. Application experiments using some of the natural insect predators (L. riparia, C. bicolor, Pogonus, Di. gustavii, Dyschirius) revealed that these solvent ratios provided a more effective deterrent than other possible ratios. Thus by combining the solvents in certain ratios, the capability of cuticular penetration and therefore the effectiveness of the defensive secretions are adapted to their natural targets.  相似文献   

13.
The politics of development includes subtexts of choice, as underpinned by community consensus (or lack of it), against the larger backdrop of a liberal democracy, with its intricate power structures that influence the choice of concepts and often lead to complicity rather than consent. A dilemma exists between the understanding of field-level practitioners and that of academics, whose understandings of progress differ. Progress can (and often does) imply long-term change across generations whereas development is often more a matter of crisis management and delivering tangible results to end-users. This makes it a bone of contention across political systems, irrespective of local or global dynamics. Development can emerge as a tool to be wielded for power and further political mileage at the expense of progress. Progress cannot be studied as a counterpoint to development as the sense of history is often missing in development interventions. Development tends to be piecemeal as its very logic often stems from the rationale of power. This is not to suggest, however, that development is only about politics; it is definitely more than the politics of everyday life and involves all of civil society that requires its critical and immediate attention. In this sense, it has become a priority for politicians with an underlying agenda designed to out-manouevre dissent and all statements of protest.  相似文献   

14.
Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay‐per‐view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per‐article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation‐oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees. Obtención de Acceso Abierto a la Ciencia de la Conservación  相似文献   

15.
As landscapes continue to fall under human influence through habitat loss and fragmentation, fencing is increasingly being used to mitigate anthropogenic threats and enhance the commercial value of wildlife. Subsequent intensification of management potentially erodes wildness by disembodying populations from landscape-level processes, thereby disconnecting species from natural selection. Tools are needed to measure the degree to which populations of large vertebrate species in formally protected and privately owned wildlife areas are self-sustaining and free to adapt. We devised a framework to measure such wildness based on 6 attributes relating to the evolutionary and ecological dynamics of vertebrates (space, disease and parasite resistance, exposure to predation, exposure to limitations and fluctuations of food and water supply, and reproduction). For each attribute, we set empirical, species-specific thresholds between 5 wildness states based on quantifiable management interventions. We analysed data from 205 private wildlife properties with management objectives spanning ecotourism to consumptive utilization to test the framework on 6 herbivore species representing a range of conservation statuses and commercial values. Wildness scores among species differed significantly, and the proportion of populations identified as wild ranged from 12% to 84%, which indicates the tool detected site-scale differences both among populations of different species and populations of the same species under different management regimes. By quantifying wildness, this framework provides practitioners with standardized measurement units that link biodiversity with the sustainable use of wildlife. Applications include informing species management plans at local scales; standardizing the inclusion of managed populations in red-list assessments; and providing a platform for certification and regulation of wildlife-based economies. Applying this framework may help embed wildness as a normative value in policy and mitigate the shifting baseline of what it means to truly conserve a species.  相似文献   

16.
Abstract: In the United States, as elsewhere, a growing debate pits national energy policy and homeland security against biological conservation. In rural communities the extraction of fossil fuels is often encouraged because of the employment opportunities it offers, although the concomitant itinerant workforce is often associated with increased wildlife poaching. We explored possible positive and negative factors associated with energy extraction in the Greater Yellowstone Ecosystem (GYE), an area known for its national parks, intact biological diversity, and some of the New World's longest terrestrial migrations. Specifically, we asked whether counties with different economies—recreation (ski), agrarian (ranching or farming), and energy extractive (petroleum)—differed in healthcare (gauged by the abundance of hospital beds) and in the frequency of sexual predators. The absolute and relative frequency of registered sex offenders grew approximately two to three times faster in areas reliant on energy extraction. Healthcare among counties did not differ. The strong conflation of community dishevel, as reflected by in‐migrant sexual predators, and ecological decay in Greater Yellowstone is consistent with patterns seen in similar systems from Ecuador to northern Canada, where social and environmental disarray exist around energy boomtowns. In our case, that groups (albeit with different aims) mobilized campaigns to help maintain the quality of rural livelihoods by protecting open space is a positive sign that conservation can matter, especially in the face of rampant and poorly executed energy extraction projects. Our findings further suggest that the public and industry need stronger regulatory action to instill greater vigilance when and where social factors and land conversion impact biological systems.  相似文献   

17.
Summary Acanthoscelides obtectus (Say) is one of the most damaging pests of kidney beans,Phaseolus vulgaris L. worldwide. However, aromatic plants from the families Lamiaceae, Lauraceae, Myrtaceae and Poaceae can protect kidney beans by direct or delayed insecticidal effect, through increased adult mortality and inhibition of beetle reproduction (both oviposition and adult emergence). The efficiency of hydrodistillated and intact plants fromThymus vulgaris andT. serpyllum, Mentha piperata, Rosmarinus officinalis, Satureia hortensis, Eucalyptus globulus, Laurus nobilis, Origanum vulgare, andCymbopogon nardus was compared. For both extracts,Origanum vulgare had the best effect. The insecticidal effect was induced by more than the essential oils because no significant difference was noticed between distilled and intact plants extract. Inhibition of reproduction was particularly important. These results suggest that lipidic as well as non lipidic, allelochemicals, such as phenolics, or non-protein amino-acids, or flavonoids may be involved in the toxicity of aromatic plants to this beetle.  相似文献   

18.
A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.  相似文献   

19.
Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.  相似文献   

20.
Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.  相似文献   

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