聚合铝基复合絮凝剂脱色性能的初步研究

以不同碱化度(B)的聚合氯化铝(PAC)和二甲基二烯丙基氯化铵均聚物(PDMDAAC)制备PAC-PDMDAAC复合絮凝剂,研究絮凝剂处理分散染料的脱色效果．结果表明,PAC-PDMDAAC较PAC具有更好的脱色效果和较低的投加量;PAC的B值和PDM-DAAC质量分数(P％)、粘度(η)对PAC—PDMDAAC的脱色效果都有不同程度的影响．     

壳聚糖/膨润土复合絮凝剂处理染料废水的研究

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。     

淀粉改性絮凝剂与PAC复合絮凝发制品废水性能研究:小试和中试

发制品在生产过程中产生大量废水,一般首先通过混凝/絮凝预处理去除废水中大部分悬浮胶体颗粒及少量可溶性物质.本研究中,设计并合成了两种含有强阳离子季铵盐基团的淀粉改性絮凝剂,分别是基团位于主链的3-氯-2-羟丙基三甲基氯化铵改性淀粉(St-CTA-DQ)和基团位于侧链的淀粉接枝聚甲基丙烯酰氧乙基三甲基氯化铵(St-g-PDMC-DQ).将它们分别在小试和中试规模下与聚合氯化铝(PAC)复合絮凝发制品废水,重点考察了复合絮凝中无机混凝剂与高分子絮凝剂的投加顺序与投加量等因素影响.实验室小试结果表明,先加PAC再加改性淀粉絮凝剂的絮凝工艺效果明显优于先加高分子絮凝剂再加PAC及两者同时加入的絮凝工艺;当与两种淀粉改性絮凝剂分别复合使用时,St-CTA-DQ与St-g-PDMC-DQ投加量分别为:10 mg·L~(-1)和20 mg·L~(-1),PAC的最佳投加量(90 mg·L~(-1))相比其单独使用(190 mg·L~(-1))下降一半以上;且复合絮凝对于浊度和UV_(254)的去除效果明显增强;形成的絮体尺寸更大,结构也更为密实;中试实验结果基本与小试一致.这是因为除了PAC电中和作用外,加入的阳离子高分子絮凝剂同时具有混凝和絮凝双重功能,能够进一步通过电中和与黏结架桥作用去除废水中污染物与初级絮体.同时还比较了上述两种阳离子淀粉改性絮凝剂不同结构对其絮凝性能影响,阳离子基团位于主链的St-CTA-DQ具有更佳的絮凝性能.淀粉改性絮凝剂与PAC复合使用在发制品废水处理中拥有良好的应用前景.     

复合脱色絮凝剂的制备及其在活性艳红X-3B染料废水处理中的应用

以双氰胺和甲醛为主原料,在添加改性剂的条件下制备了改性双氰胺-甲醛缩聚物,并直接与硫酸亚铁复合成脱色絮凝剂;以活性艳红X-3B染料废水的脱色率和CODCr去除率为考核指标,探讨了硫酸亚铁投加方式、复合质量比、pH等因素对活性艳红X-3B处理效果的影响。研究结果表明,在一定投加量下,复合脱色絮凝剂处理活性艳红X-3B染料废水的脱色率和COD去除率分别为99%和约75%左右。     

PDMDAAC系列絮凝剂的脱色性能研究

研究了二甲基二烯丙基氯化铵聚合物（PDMDAAC）系列絮凝剂对活性染料废水和分散染料废水的脱色效果，考察了絮凝剂的特性粘度、阳离子度及结构等因素对脱色效果的影响，探讨了其脱色机理，并试验了与PAC复配的脱色效果。实验结果表明：絮凝剂的特性粘度越高，阳离子度越高，脱色效果越好；絮凝剂结构中引入乙烯基三甲氧基硅烷（VTMS）可使脱色效果胡所提高；PDMDAAC系列絮凝剂处理活性染料废水的机理是通过电中和作用，使染料分子从水中析出，然后通过吸附架桥作用使之聚集、沉降除去；PDMDAAC系列絮凝剂在处理分散染料废水时，吸附架桥为主导作用；PDMDAAC系列絮凝剂与PAC复配可使脱色效果更佳而且可以降低处理成本。     

铝铁改性淀粉复合絮凝剂对甲基紫的絮凝机理

以模拟甲基紫染料废水为处理对象,通过测定絮凝R值、Zeta电位、脱色率与CODCr去除率,研究了自配铝铁改性淀粉复合絮凝剂(CAFS)的絮凝特性,初步探讨了其絮凝机理.结果表明,该复合絮凝剂为阳离子型高分子絮凝剂,絮凝初期作用机理趋于"吸附电中和",絮凝后期作用机理以"絮凝架桥"和"卷扫网捕"为主,絮凝性能受pH值影响显著.在pH=11.0,投加量为0.330 mg·L-1时,甲基紫处理效果最优,CODCr去除率达41.0%,色度去除率高达98.0%,其絮体形态密实、含水率低.     

聚合铝基复合混凝剂残余铝及混凝性能的初步研究

以不同碱化度(B)的聚合氯化铝(PAC)和二甲基二烯丙基氯化铵均聚物(PDMDAAC)制备聚合氯化铝-二甲基二烯丙基氯化铵均聚物复合混凝剂(PAC-PDMDAAC)，试验了其处理模拟水的除浊效果及水体的残余铝量。结果表明：PAG-PDMDAAC较PAC具有更低的投加量，更好的除浊效果，处理后水体具有更低的残余铝量。B和PDMDAAC质量百分含量(P％)对PAC-PDMDAAC除浊效果及水体的残余铝量有不同程度的影响。     

壳聚糖复合絮凝剂在城市生活污水处理中的应用

研究了壳聚糖复合絮凝剂在不同来源的城市生活污水处理中的应用 ,确定了壳聚糖复合絮凝剂在城市生活污水处理中的最佳投加量 ,即 :最佳投加量 (mg·l- 1)∶原水COD (mg·l- 1) =1∶8 2— 8 7和最佳pH =7;它与传统的絮凝剂PAC同比 ,COD去除率提高 7— 1 3% ,SS去除率提高 3— 1 0 % ,[Al3 + ]下降 6 1— 85 % ,药剂加量减少76— 82 % .     

Fenton法-聚合氯化铝预处理高浓度乳化液废水

乳化液在机械制造、加工等过程中有广泛的应用,主要起润滑、冷却、表面清洗和防腐蚀作用。其主要成分为矿物油、表面活性剂、抑菌剂和其他有机添加剂,在使用过程中产生了高浓度、乳化严重、成分复杂且波动大的乳化液废水,随意排放会对环境造成严重污染;目前国内外对低浓度含油废水的处理进行了大量的研究工作,如各种破乳法、微生物法等,但各种处理方法都有其局限性,尤其对高浓度乳化液废水尚没有定型的处理方法。Fenton氧化法是一种高级氧化技术,在酸性条件下,H2O2被Fe2+催化分解并产生大量具有强氧化性的?OH,通过?OH氧化降解废水中的有机物,达到废水净化的目的。在处理有毒有害难生物降解有机废水方面具有较强的应用优势;聚合氯化铝(PAC)是一种应用很广的无机高分子絮凝剂,与其它水处理剂配合使用具有更好的水处理效果,通过Al(Ⅲ)盐水解-聚合产物对水中胶体颗粒或胶体污染物进行电性中和、脱稳和吸附架桥作用生成粗颗粒絮凝体去除,从而达到净化污水的目的;本文采用Fenton法-聚合氯化铝组合工艺预处理机械加工厂高浓度乳化液废水以满足后续生化处理进水要求,通过实验研究了Fenton法涉及的初始反应pH值、H2O2投加量、硫酸亚铁投加量、反应时间和后续投加聚合氯化铝涉及的反应pH值、PAC投加量及反应时间对乳化液废水预处理效果的影响。结果表明,Fenton法处理乳化液废水的最佳反应条件为:pH值为2、H2O2投加量为48 mL·L-1、质量分数为10%的FeSO4投加量为88 mL·L-1和反应时间为60 min;后续投加PAC处理的最佳反应条件为:pH值为7、质量分数为10%的PAC投加量为466 mL·L-1、反应时间为40 min;乳化液废水COD约34000 mg·L-1,经Fenton法-聚合氯化铝组合工艺处理后处理水COD小于5 000 mg·L-1,COD去除率达到87%以上,色度从浑浊的乳白色变成了清澈的无色,满足了后续生化处理对进水的水质要求。可为解决同类高浓度乳化液废水预处理提供技术参考。     

阳离子化克雷伯氏菌絮凝剂CMBF-NⅢ2在生活污水中的应用

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.     

Achieving Open Access to Conservation Science

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     

Rapid,recurring, structured survey versus bioblitz for generating biodiversity data and analysis with a multispecies abundance model

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.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

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.     

Some polyphagous Homoptera gain protection from their natural enemies by feeding on the toxic plantsSpartium junceum andErythrina corallodendrum (Leguminosae)

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.     

A palaeo-hydrogeological model for arsenic contamination in southern and south-east Asia

An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.     

Sequestration of cucurbitacin analogs by New and Old World chrysomelid leaf beetles in the tribe Luperini

Summary Two South American polyphagous leaf beetles,Diabrotica speciosa andCerotoma arcuata, selectively accumulated the bitter tasting compound 23,24-dihydrocucurbitacin D in their body after ingesting root tissues of cucurbit plants. Similarly, three Asian Cucurbitaceae-feeding specialists in the genusAulacophora were found to sequester the same compound. Cucurbitacin analogs were shown to deter feeding by a bird predator, indicating an allomonal role for these compounds in cucurbitacin-associated chrysomelid leaf beetles both of New and Old Worlds. The strong affinity to cucurbitacins, selective sequestration of the analogs and consequent protection from predators suggested an ecological adaptation mechanism developed in common among these two geographically isolated subtribes in the Luperini.     

Threats to intact tropical peatlands and opportunities for their conservation

Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza‐Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land‐use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon‐dense (domed pole forest) areas. New carbon‐based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development.     

Effects of Controlled Fire and Livestock Grazing on Bird Communities in East African Savannas

Abstract: In East Africa fire and grazing by wild and domestic ungulates maintain savannas, and pastoralists historically set fires and herded livestock through the use of temporary corrals called bomas. In recent decades traditional pastoral practices have declined, and this may be affecting biodiversity. We investigated the effects of prescribed fires and bomas on savanna bird communities in East Africa during the first and second dry seasons of the year (respectively before and after the rains that mark the onset of breeding for most birds). We compared abundance, richness, and community composition on 9‐ha burned plots, recently abandoned bomas, and control plots in the undisturbed matrix habitat over a 3‐year period. Generally, recently burned areas and abandoned bomas attracted greater densities of birds and had different community assemblages than the surrounding matrix. The effects of disturbances were influenced by interactions between primary productivity, represented by the normalized difference vegetation index, and time. Bird densities were highest and a greater proportion of species was observed on burned plots in the months following the fires. Drought conditions equalized bird densities across treatments within 1 year, and individuals from a greater proportion of species were more commonly observed on abandoned bomas. Yearly fluctuations in abundance were less pronounced on bomas than on burns, which indicate that although fire may benefit birds in the short term, bomas may have a more‐lasting positive effect and provide resources during droughts. Several Palearctic migrants were attracted to burned plots regardless of rainfall, which indicates continued fire suppression may threaten their already‐declining populations. Most notably, the paucity of birds observed on the controls suggests that the current structure of the matrix developed as a result of fire suppression. Traditional pastoralism appears critical to the maintenance of avian diversity in these savannas.     

Cost‐effective conservation of an endangered frog under uncertainty

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.