UASB反应器处理味精生产废水的研究

用厌氧颗粒污泥接种的UASB反应器经驯化后,仅一个月处理味精生产废水容积负荷,由1.87kg COD/m~3·d提高到18.9kg COD/m~3·d,进料浓度COD4500—5000mg/L,去除率约80％,产气正常,抗负荷变化性能良好。 反应器工艺设计参数:进料浓度COD 5000mg/L,容积负荷10—15kg COD/m~3·d,去除率80％,操作温度38±1℃。提出了处理味精生产废水的整个工艺流程和有待进一步试验解决的问题。     

无色硫细菌氧化SRB还原硫酸盐产物硫化氢生成单质硫

以人工合成含硫化物废水作为进水 ,采用以陶粒为填料、小试规模的逆流式和顺流式好氧CSB(无色硫细菌 )生物膜反应器 ,在常温 ( 1 7℃～2 2℃ )、HRT为 2 6min、进水pH为 7.0和对反应器中pH不进行控制的条件下 ,研究了利用CSB将水中硫化物转化成单质硫的可行性及条件。实验表明 :为达到硫的最大回收率 ,在硫化物低负荷(NS <6 .1kg/ (m3 ·d) )时建议采用顺流式 ,高负荷 (NS>6 .1kg/ (m3 ·d) )时采用逆流式 ;反应器内的最佳DO值与进水硫化物容积负荷呈线性关系 ,出水pH值和出水pH值的升高值与硫的回收率呈线性关系。此外还研究了反冲洗对生物脱硫效果的影响及尾气中H2 S的生物去除     

上流式厌氧污泥床滤层反应器处理鸡粪混合液离心出水

本研究采用上流式厌氧污泥床滤层反应器对蛋鸡场鸡粪混合液离心出水进行处理,试验结果:在中温25℃,进水COD_(cr)18000mg/L和氨氮1600mg/L的条件下,COD_(cr)去除率74.08%,BOD_5去除率83.78%,水力停留时间26.15h,容积负荷15.60kg·COD_(cr)/m~3·d,产气率0.52m~3/去除km·COD_(cr).反应器运行状况良好.     

UASB反应器处理生活污水的自接种启动

本试验利用未沉淀的生活污水(COD在432mg/L左右)在7℃～22℃温度下自接种启动容积为5L的升流式厌氧污泥层反应器.初始有机容积负荷为1.75kgCOD/m~3·d,水力停留时间为5.9h.运行57天时出现了颗粒污泥,此时污泥负荷为0.33kgCOD/kgVSS·d.106天后反应器达到稳定的处理效果.当温度在20℃左右,HRT为6h,COD去除率达81.2%,出水COD低于100mg/L.培养出的颗粒污泥呈黑色,粒径在0.5mm～3mm之间,比重为1.04, SVI在15左右,有较好的沉降性和产甲烷活性.污泥中产甲烷菌主要是素氏甲烷丝菌.     

厌氧好氧一体化生物反应器处理发酵废水的研究

采用新型厌氧好氧一体化生物反应器对发酵废水进行了中试处理研究.试验结果表明,系统总有机负荷最高可达到8.88kg(COD)m-3d-1,系统去除率稳定在88.10%~96.88%,说明反应器处理效率高,抗冲击能力强.反应器结构合理,利于保持丰富、高活性的微生物,反应器厌氧区颗粒污泥TS高达83.9gL-1,VS/TS为56.9%~57.4%,比产甲烷活性为280~350mL(CH4)gvss-1d-1;好氧区固定化微生物TS高达64.03gL-1载体,VS/TS为94.02%~94.30%.反应器各功能区对废水的降解过程分析,说明反应器厌氧区和好氧区一体化结构合理,可将废水逐级降解,从而保证整个系统的处理效果.图8表4参11     

气动厌氧流化床处理高浓度有机废水的研究

本文针对目前厌氧流化床研究中存在的一些问题,首次采用气动厌氧流化床处理高浓度有机废水,并就有机物去除的数学模式以及影响因素作了探讨。当载体选用经过强化处理的固定化微生物颗粒时,试验结果表明,对进水COD浓度为10,000mg/L左右的人工污水,当容积负荷为20kgCOD/m~3·d时,COD去除率可达85％,进而确定在温度、水力停留时间、进水COD浓度、容积负荷四个因素中,温度对COD去除率影响最大,容积负荷影响最小。     

不同温度下氨对疫病动物尸骸废水厌氧消化的影响

采用厌氧折流板反应器处理疫病动物尸骸废水,研究了反应器由中温(35℃)逐步升至高温(55℃)时的运行特性.结果表明,升温至45℃和55℃时,厌氧处理效率显著降低,将有机负荷由35℃时的6.0 kg COD·(m~3·d)~(-1)降至55℃时的2.4 kg COD·(m~3·d)~(-1)并没有得到恢复,高温厌氧COD去除率相比中温下降了24%,甲烷产率下降了33%,出水挥发性脂肪酸(VFAs)增加了1.9倍.升温过程中,厌氧产甲烷菌受到了游离氮(FAN)的抑制导致甲烷产率显著降低.当温度由35℃升至55℃时,反应器p H值由7.63升至8.22,FAN由98 mg·L~(-1)升至340 mg·L~(-1),VFAs由235 mg·L~(-1)积累至684 mg·L~(-1),p H、FAN和VFAs三者的协同作用导致反应器在高温状态下处于"抑制稳态".与中温厌氧相比,高温菌对FAN的耐受性更强.当p H值为8.2时,FAN对中温菌的IC50为324 mg·L~(-1),对高温菌则达到453 mg·L~(-1),但这一优势不能抵消升温所引起的FAN抑制效应.这是疫病动物尸骸废水高温厌氧消化效率显著低于中温的主要原因.     

温度及氨氮负荷对曝气生物滤池硝化作用的影响

采用火山岩为载体填料的曝气生物滤池(BAF)进行实验室小试,研究供氧受限条件下,BAF的硝化反硝化运行特性及温度(10℃～30℃)和氨氮负荷变化(0.069～1.32kg/(m3·d))时对硝化作用的影响。当氨氮负荷为1.10kg/(m3·d),供氧受限时,温度从20℃升高到30℃,反应器的硝化效率仅增加10%左右,表明BAF中硝化作用主要受溶质的传递、扩散速率控制而不是受与温度有关的动力学参数控制;然而,相同负荷下,当温度控制在15℃时,硝化效率明显降低,说明20℃是一临界点。此外,20℃时随氨氮负荷的增加(从0.825kg/(m3·d)提升到1.32kg/(m3·d)),氨氮去除率略有下降,但在第3个取样口处却发现有亚硝酸盐氮累积现象,这是因为在供氧受限时,随负荷的增加,溶解氧相对短缺发生了部分硝化作用。     

厌氧浮动生物膜反应器处理高浓度有机废水

本文探讨了厌氧浮动生物膜反应器、处理高浓度有机废水的研究。试验结果表明，在温度２０℃￣２８℃，容积负荷为５．３８￣２０．６２ｋｇＣＯＤ／ｍ＾３·ｄ，水力停留时间２３．４ｈ，ＣＯＤ去除率在９０％以上，反应器内污泥持留量高，抗冲击负荷能力强。微生物既有附着生长系统，也有大量悬浮颗粒污泥，生物膜中与颗粒污泥中的生物相有明显差异。     

氨氮废水的厌氧氨氧化生物脱氮研究

利用从厌氧污泥中筛选和驯化的厌氧氨氧化（Anammox）菌直接启动UASB反应器,通过缩短水力停留时间（HRT）提高系统运行负荷,探讨水力停留时间对模拟废水脱氮性能的影响。结果表明,（1）富含Anammox菌的颗粒污泥能够快速启动反应器（只需14d）。（2）连续91d的HRT测试期间,系统具有良好的脱氮性能,且随着HRT的缩短,系统的脱氮效率具有波动上升的特点。NH4＋-N、NO2--N和TN（总氮）的平均去除率超过70.0%。（3）系统总氮容积负荷（TNLR）和总氮去除负荷（TNRR）最大值（以N计）分别为2.04kg·m-3·d-1和1.56kg·m-3·d-1。（4）系统能够比较好的遵循Anammox生物脱氮的理论途径：NH4＋-N、NO2--N的去除速率与NO3--N的生成速率的比例为1？1.15？0.22,与其相应理论值（1？1.32？0.26）非常接近。     

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.     

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.     

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.     

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.     

Parasitic wasps orient to green leaf volatiles

Summary Undamaged plants emit low levels of green leaf volatiles (GLVs), while caterpillar-damaged and artificially damaged plants emit relatively higher levels of certain GLVs. Female braconid parasitoids,Microplitis croceipes, oriented to both damaged plants and to individual GLVs in no-choice tests in a wind tunnel, but seldom oriented to undamaged plants. Female ichneumonid parasitoids,Netelia heroica, also oriented to individual GLVs in a wind tunnel. Males of both wasp species failed to orient to the GLVs. These data show that leaf-feeding caterpillars can cause the release of GLVs, and that parasitic wasps can respond to these odors by flying upwind (chemoanemotactic response), which brings the wasps to their caterpillar hosts. This supports the hypothesis that plants communicate with members of the third trophic level,i.e., plants under herbivore attack emit chemical signals that guide natural enemies of herbivores to sites of plant damage. In this interaction, the GLVs serve as tritrophic plant-to-parasitoid synomones. That parasitoids from two different wasp families oriented to GLVs suggests that the response may be widespread among the Hymenoptera.Mention of a commercial or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture     

Human Influence and Classical Biogeographic Predictors of Rare Species Occurrence

Biogeographic theory predicts that rare species occur more often in larger, less‐isolated habitat patches and suggests that patch size and connectivity are positive predictors of patch quality for conservation. However, in areas substantially modified by humans, rare species may be relegated to the most isolated patches. We used data from plant surveys of 81 meadow patches in the Georgia Basin of Canada and the United States to show that presence of threatened and endangered plants was positively predicted for patches that were isolated on small islands surrounded by ocean and for patches that were isolated by surrounding forest. Neither patch size nor connectivity were positive predictors of rare species occurrence. Thus, in our study area, human influence, presumably due to disturbance or introduction of competitive non‐native species, appears to have overwhelmed classical predictors of rare species distribution, such that greater patch isolation appeared to favor presence of rare species. We suggest conservation planners consider the potential advantages of protecting geographically isolated patches in human‐modified landscapes because such patches may represent the only habitats in which rare species are likely to persist. Influencia Humana y Predictores Biogeográficos Clásicos de la Ocurrencia de Especies Raras     

Seasonal dynamics of macro-algae in the South Lake of Tunis

The macro-algae communities observed in the south lake of Tunis are characterized by the predominance of nitrophilous algae which are in the order of biomass importance:Ulva, Cladophora andEnteromorpha. We have noted seasonal changes of alga distribution. The wind appears to be one of the most important factors influencing this distribution. The total biomass reaches a maximum in the spring. Rapid decomposition of the biomass leads to a severe ecological imbalance, resulting in crises of anoxia and fish death. A restoration project has already started. It aims at removal of contaminated muds and the introduction of a new circulation system. The main objectives of this work were to collect information on the distribution and biomass of the phytobenthic communities as a first step in the constitution of a database for further comparison.     

Patterns and biases of climate change threats in the IUCN Red List

International Union for Conservation of Nature (IUCN) Red List assessments rely on published data and expert inputs, and biases can be introduced where underlying definitions and concepts are ambiguous. Consideration of climate change threat is no exception, and recently numerous approaches to assessing the threat of climate change to species have been developed. We explored IUCN Red List assessments of amphibians and birds to determine whether species listed as threatened by climate change display distinct patterns in terms of habitat occupied and additional nonclimatic threats faced. We compared IUCN Red List data with a published data set of species’ biological and ecological traits believed to infer high vulnerability to climate change and determined whether distributions of climate change‐threatened species on the IUCN Red List concur with those of climate change‐threatened species identified with the trait‐based approach and whether species possessing these traits are more likely to have climate change listed as a threat on the IUCN Red List. Species in some ecosystems (e.g., grassland, shrubland) and subject to particular threats (e.g., invasive species) were more likely to have climate change as a listed threat. Geographical patterns of climate change‐threatened amphibians and birds on the IUCN Red List were incongruent with patterns of global species richness and patterns identified using trait‐based approaches. Certain traits were linked to increases or decreases in the likelihood of a species being threatened by climate change. Broad temperature tolerance of a species was consistently related to an increased likelihood of climate change threat, indicating counterintuitive relationships in IUCN assessments. To improve the robustness of species assessments of the vulnerability or extinction risk associated with climate change, we suggest IUCN adopt a more cohesive approach whereby specific traits highlighted by our results are considered in Red List assessments. To achieve this and to strengthen the climate change‐vulnerability assessments approach, it is necessary to identify and implement logical avenues for further research into traits that make species vulnerable to climate change (including population‐level threats).