膜生物反应器（MBR）处理不同浓度高硫酸盐有机废水污泥性质和膜污染研究

针对食品加工过程中产生的高SO₄^2-的高浓度有机物废水,采用膜生物反应器(MBR)工艺对其进行处理研究,分别考察了1.6%和2.6%SO₄^2-浓度下反应器运行性能、污泥性质和膜污染变化情况.经过110 d的运行时间对比发现,1.6%SO₄^2-浓度下MBR获得的最大有机负荷为1.0kg·(m³·d)^-1 COD,其化学需氧量(COD)、氨氮和总氮的去除率分别为97.2%、92.5%和89.5%.2.6%SO₄^2-浓度下微生物受到的抑制更强,其获得的最大有机负荷仅为0.5 kg·(m³·d)^-1 COD,其COD、氨氮和总氮的去除率分别为96.3%、82.6%和80.7%.此外,SO₄^2-浓度为1.6%的反应器在更高的膜运行通量下,膜污染速率反而比2.6%系统更慢.进一步分析其污泥性质发...     

SMBR不同特性膜处理城市内河道水对比试验研究

用一体浸没式膜生物反应器(SMBR)不同特性膜处理上海市城市内河道水,结果表明,SMBR对氨氮含量较高的富营养化河水,氨氮的去除率在90%以上,但对COD的平均去除率仅为50%.比较两种膜的运行性能,亲水性膜在运行通量和通量恢复能力上,均比疏水性膜优越.两种膜的出水水质几乎没有差异.     

膜生物反应器投加PAC处理生活污水效能的试验

在一体式MBR系统中投加少量的粉末活性炭，运行效果良好，并且可以很好地降低膜污染。粉末活性炭在形成生物活性炭后，对难降解有机物具有很好的降解能力；NH4^ -N的去除率得到进一步提高，NO3^-的含量升高；但反硝化作用不明显，致使总氮去除率不高；生物活性炭很好地吸附并降解了易引起膜污染的有机物，改变了污泥的性质，对膜组件起到了很好的保护作用。     

膜生物反应器（MBR）处理垃圾渗滤液的脱氮研究

采用一体式MBR处理垃圾渗滤液,系统考察MBR对COD、NH4＋-N和TN的去除效果。结果表明：可将垃圾渗滤液的COD降至650-1 500 mg·L-1范围;在HRT为1.5 d、DO为0.75-1.20 mg·L-1、不排泥条件下运行时,对TN质量浓度低于2 300 mg·L-1、容积负荷低于0.25 kg.m-3.d-1（以N计）的渗滤液进行处理,MBR对NH4＋-N与TN的去除率可分别达到87%和72%以上。在MBR处理垃圾渗滤液的运行中发现,膜的污染速度较快,并且呈现＂两段性＂的规律,采用碱＋氧化剂的清洗方式可有效去除膜污染,降低过膜压力。     

膜生物反应器高度净化有机物的特性

分别采用膜生物反应器(MBR)和普通生物反应器(CSTR)对苯胺废水进行处理，结果表明MBR处理效果优于CSTR，处理水苯胺浓度接近动力学极限浓度。测定了两种反应器中微生物的最大比基质利用速率qmax分别为2．084d^-1和1．650d^-1，亲和常数Ks值分别为0．237mg／L和0．309mg／L。间歇试验证明MBR能富集培养基质亲和性高的专一性微生物。这类微生物降解速率不随基质浓度而变化，且能更彻底地降解有机物，适用于微量有机物的高度净化。     

在线反冲洗控制MBR膜污染的试验

试验采用在线空气反冲洗和在线清水反冲洗控制膜生物反应器(MBR)膜污染。试验结果表明,通过在线空气反冲洗,膜通量最大可恢复至20.5L/(m2·h),恢复率为95.3%,反冲洗周期为5d,且30d后膜通量仍大于12L/(m2·h);采用在线清水反冲洗后,膜通量最大可恢复至20.9L/(m2·h),恢复率为97.7%,第34天进行第3次在线清水反冲洗后膜通量仍可恢复至19.8L/(m2·h)。     

垃圾渗滤液中有机物分子量的分布及在MBR系统中的变化

利用凝胶层析方法分析了垃圾渗滤液中有机物分子量的分布情况,并考察了利用膜生物反应器(MBR)处理垃圾渗滤液系统中有机污染物分子量的分布以及水溶性腐殖质(AHS)含量的变化．研究发现,垃圾渗滤液中的有机物主要由两部分组成,即分子量大于6000的大分子物质和分子量小于1500的小分子物质．大分子物质主要是水溶性腐殖质,而小分子物质主要由挥发性有机酸及水溶性腐殖质组成．大分子的AHS难以被微生物降解,但能被微滤膜截留．大部分小分子的AHS既难以被微生物降解,又不能被膜截留,是构成MBR处理出水COD的主要成分．     

不同汲取液在正渗透膜处理垃圾渗滤液过程中的作用

以垃圾渗滤液处理过程中的膜生物反应器(Membrane Bio-Reactor,MBR)出水作为研究对象,采用正渗透膜技术对其进行过滤,对比选择碳酸氢铵和乙二胺四乙酸(Ethylene Diamine Tetraacetic Acid,EDTA)-锌钠两种汲取液中性能较好的进行中试实验。研究了两种汲取液的不同浓度及膜朝向对膜通量的影响,检测了两种汲取液长时间运行所能达到的回收率,分析了两种汲取液的污染物截留率,用斑马鱼胚胎评估了垃圾渗滤液经两种汲取液处理后的生物毒性。结果表明:膜通量随着汲取液浓度增加而增加;在减压渗透(Pressure Reduced Osmosis,PRO)模式下的通量较正渗透(Forward Osmosis,FO)模式高,但污染较严重;碳酸氢铵和EDTA-锌钠在PRO和FO模式下的回收率分别为86.6%、91.6%和66.5%、71.2%;两种汲取液处理后的污染物截留率相差无几,都在98%以上;斑马鱼胚胎暴露于纯水、碳酸氢铵、EDTA钠盐汲取液处理后的水和垃圾渗滤液MBR出水中三天之后存活率为81%、76%、68%和0;实验说明相比于EDTA-锌钠,碳酸氢铵性能较好,适合进行下一步中试试验。     

MBR处理不同浓度高硫酸盐有机废水效能比较

针对食品加工过程中产生的高SO₄^2-有机物废水,采用MBR工艺对其进行处理研究,分别考察了1.6%和2.6%SO₄^2-浓度下反应器容积负荷和污染物去除情况.经过110天的运行时间发现,进水SO₄^2-浓度为1.6%的系统能获得更高的容积负荷和污染物去除效率,其最大容积负荷为1.0 kg·(m³·d)^-1COD,COD去除率为97.7%;而另一方面较高的无机盐环境进水SO₄^2-浓度为2.6%SO₄^2-系统下,获得的最大容积负荷仅为0.5 kg·(m³·d)^-1(按COD算),COD去除率为96.4%.在2.6%SO₄^2-浓度下,微生物受到的抑制更强,有机物降解效果低于1.6%SO₄^2-的系统.此外,氨...     

生物膜法A/O/O工艺城市污水脱氮处理的挂膜启动

生物膜法A/O/O脱氮系统处理城市污水中试挂膜启动研究结果表明:挂膜启动的关键在于进行硝化处理的二级生物接触氧化池能否培养出以硝化菌为优势菌种的成熟生物膜。试验中水温、气水比和进水氨氮负荷是影响挂膜启动的主要因素。为加速挂膜启动,水温不宜低于15℃;挂膜初期在保证供氧充足的情况下最好采用较小的气水比,而后气水比可逐渐随DO的实际需求作相应的调整,同时保持出水DO不低于4mg/L,5.5～6mg/L时效果较好;启动期内氨氮负荷宜低于0.6kg/(m3·d)。     

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.