废水回用工艺中曝气生物滤池的特性研究

以页岩陶粒为滤料,对曝气生物滤池的运行性能进行了研究。通过考察水力负荷对COD、氨氮去除效果的影响试验,容积负荷对COD去除效果试验,BAF对浊度的去除效果、抗冲击能力试验;结果显示:COD最佳水力负荷为7.0m3/h,NH4+-N最佳水力负荷为5.0m3/h,COD最佳容积负荷为5.89kg/(m3.d);进水浊度平均为12.7NTU,出水浊度平均为3.5NTU时,平均去除率为72.4%。水力冲击负荷对硝化菌的影响较小,而对异养菌影响较大。     

港东联合站外排污水深度处理工艺研究

为解决港东联合站外排污水2010年前达标排放的问题,需在现有氧化塘生化处理工艺的基础上,进行工艺优化和深度处理。通过对港东联合站外排污水的分析,发现现有处理系统的问题,并结合水质特性和现有处理工艺进行试验研究。结果表明:采用曝气生物滤池工艺,以兼性塘进水为水源,流量150L/h,BAF对CODCr的去除率为68.1%;采用活性炭吸附技术,在水力负荷不超过2.1m3/(m2.h)情况下,活性炭出水CODCr平均值为27.3～37.4mg/L,对CODCr的去除率在60%以上;曝气生物滤池与活性炭吸附工艺对CODCr、石油类、悬浮物的处理指标都达到了天津市地方标准DB12/356-2008《污水综合排放标准》的要求。     

高盐度气田废水处理试验研究

以某污水厂好氧污泥为接种污泥,半软性纤维填料为载体,采用逐步提高盐度和有机负荷的方法对生物膜进行耐盐性和高有机负荷驯化。结果表明:经过一段时间驯化所得异养生物膜能够适应高盐度和高有机负荷的环境;生物膜对环境盐度变化的适应性有一定的波动;生物膜对有机物的降解能力随系统有机负荷增大而降低,连续进水、出水不回流且流量为0.292L/h,HRT为24h条件下,COD去除率最后保持在65%左右;COD去除率达到65%的时间与系统有机负荷呈线性正相关,相关系数为0.9112;驯化后耐盐微生物对温度和酸碱度不敏感,最佳生长温度为23℃,pH值为7~8。     

玻璃蚀刻液废水中氨氮和氟去除研究

研究了MAP法(Magnesium Ammonium Phosphate磷酸铵镁结晶法)和化学沉淀法对玻璃蚀刻液废水中氨氮和氟的去除效果,获得了最佳工艺参数并形成了一套玻璃蚀刻液废水处理工艺。采用N/P/Mg投加比例为1∶1∶1的两级MAP法和Ca/F投加比为1. 8的两级化学沉淀法,并在两级氨氮和氟去除反应后分别添加PAC-PAM (聚合氯化铝-聚丙烯酰胺)为40 mg/L、2mg/L和20 mg/L、1mg/L进行絮凝沉淀,最终出水氨氮和氟的去除率分别可以达到96. 8%和99. 9%;对出水进行折点加氯处理,氨氮最终去除率可达99. 9%,出水可达到国家污水综合排放标准。     

复合式厌氧反应器处理生活污水运行特性研究

本文对复合式折流板厌氧反应器处理生活污水的运行特性进行了研究,并作了灵敏度分析。结果表明:HABR反应器因其特殊的结构而具有很好的耐冲击负荷能力及很好的去除效果;当进水的CODCr在300mg/L左右,温度在16 3～30 5℃时,水力停留时间采用6h,容积负荷为1 2kgCOD/m3·d左右,COD去除率可保持在70%以上,出水CODCr可小于100mg/L,出水SS浓度在27～64mg/L之间;各操作参数对HABR反应器CODCr去除率的影响有显著性不同;HRT是系统运行过程中需严格控制的关键因素。     

陶粒-沸石-活性炭组合填料生物滤池的研究

采用陶粒、沸石、活性炭填料合理组合作为曝气生物滤池的填料对高校生活污水进行处理。研究了组合填料生物滤池生物膜的培养,不同水力负荷、容积负荷和气水比对污水处理效率的影响,以及该生物滤池对生活污水的处理效果。结果表明,采用组合填料生物滤池,接种挂膜培养周期为25d,在水力负荷为2．5m3／（m2·h）,气水比3．5：1,组合填料生物滤池出水COD、BOD5、SS、NH3-N和色度平均值达到《城市污水再生利用城市杂用水水质》GB／T18920—2002水质要求。     

纳米二氧化钛光催化氧化降解苯酚废水实验

开展实验室模拟苯酚废水的二氧化钛光催化氧化实验。结果表明：在苯酚废水曝气量为0～3L/min的条件下，随着曝气量的增大，COD去除率先增大后减小；初始浓度不变，光照时间为1h的条件下， 调节pH值在3～11，苯酚废水COD去除率随着pH值的增大而减小，当pH值为11时， COD去除率又开始增 大，酸性条件比碱性条件下COD去除率高；随着二氧化钛投加量的增加，COD去除率增大，当二氧化钛投加量 为10g/L时，COD去除率反而降低，二氧化钛最佳投加量为3g/L；随着苯酚废水初始浓度由75mg/L增加至300mg/L，COD去除率由78.2％降低到58.1％；反应温度的改变对COD和TOC的去除率没有影响。     

复式潜流湿地净化生活污水的试验研究

研究了新型复式潜流人工湿地对生活污水的净化效果。在不同水力负荷、季节、曝气方式等条件下经过小试试验,分析了该湿地对污染物净化效果的影响。结果表明,该系统出水水质稳定,达到《城镇污水处理厂污染物排放标准》（GB18918--2002）的一级A标准。在水力负荷184mm·d。条件下COD、NH,一N去除率最大分别可达87．2％、68．9％。冬季低温条件下对各类污染物去除率仍大于20％。正交试验分析得知,最佳运行条件是气温28．6℃、水力负荷0．184m3·m-2·d-1、水力停留时间2．4d。对比试验表明,采用预曝气方式对湿地净化效果明显优于厌氧处理。     

不同水力负荷条件下的人工湿地污染处理效果分析

本文研究了水力负荷对抚仙湖北岸典型人工湿地净化河道污水处理效率的影响。研究表明,TN、TP及SS去除率随着水力负荷的增加而下降,COD去除率受水力负荷的影响程度相对较小。综合考虑水力负荷对氮磷、有机物及悬浮物等水质净化效果的影响,如果不考虑其它因素,仅从系统处理效果的角度选择水力负荷,人工湿地系统的最佳水力负荷为0.5 m3/m2·d以下。     

SBBR处理垃圾渗滤液初探

本文初步研究了用SBBR法处理垃圾渗滤液的处理效果。在驯养结束后的20个连续运行周期里,控制曝气量为250 L/h,温度为27℃,有机负荷为0.4 Kg(BOD5)/m3.d。当系统进水CODCr,NH3-N分别为810 mg/L和93 mg/L时,系统出水CODCr,NH3-N分别为160 mg/L和28 mg/L,运行结果表明:该系统在此条件下可以稳定运行。在此基础上,维持有机负荷和温度不变,在曝气量为150 L/h,200 L/h,250 L/h时分别测定不同进水水质时CODCr,氨氮的去除率。实验结果表明:当气量为250 L/h时,CODCr的去除率随进水CODCr浓度的升高而升高;当进水CODCr为790 mg/L时,CODCr的去除率随气量的升高而升高,去除率为65.78%~79.68%,并且在1小时以后有较高的去除率。稳定运行8小时之后,去除率较接近各自的最高去除率。当气量为250 L/h时,氨氮的去除率随进水氨氮浓度的升高而降低;当进水氨氮较低时(低于50 mg/L),氨氮的去除率随曝气量的升高而升高,去除率为62.07%~97.69%。     

Conversion of temperate forests into heaths: Role of ecosystem disturbance and ericaceous plants

Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into heaths. The process of disturbance-induced heath formation is documented by using examples ofCalluna in western Europe,Kalmia in Newfoundland, andGaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth ofCalluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed habitats. If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controllingKalmia andGaultheria, however, have yet to be developed. While theKalmia- andGaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range ofCalluna heathlands of western Europe are being conserved as natural and seminatural vegetation.     

BIOLOGICAL INDICATORS AND BIOLOGICAL EFFECTS OF ESTUARINE/COASTAL POLLUTION1

ABSTRACT: Sustained interest in and concern about the health status of the aquatic environment has resulted in extensive research focused on (1) effects of pollution on survival, growth, and reproduction of resource species at all life stages; (2) diseases of fish and shellfish, as they may be related to pollution and as they may serve as indicators of environmental stress; and (3) contaminant body burdens in fish and shellfish - their effects on the aquatic animals and their potential effects on humans. Effects, lethal and sublethal, of pollutants on life history stages of fish and shellfish have been documented, as have impacts on local stocks in badly degraded habitats, but as yet there has been no adequate quantitative demonstration of effects on entire aquatic species - probably because of the difficulty in sorting out relative effects of the many environmental factors that influence abundance. Sublethal effects, especially those that result in disease, have been examined intensively, and some diseases and disease syndromes have been associated statistically with pollution. Other pollution indicators (biochemical, physiological, genetic, behavioral, and ecological) have also received some attention, as have body burdens of contaminants in aquatic species. Research, especially that conducted during the past decade, has done much to clarify the many pathways and toxic effects of contaminants on aquatic animals, and has also helped to identify mechanisms for survival of fish and shellfish in the presence of environmental changes caused by human activities.     

Urban ecological systems: scientific foundations and a decade of progress

Urban ecological studies, including focus on cities, suburbs, and exurbs, while having deep roots in the early to mid 20th century, have burgeoned in the last several decades. We use the state factor approach to highlight the role of important aspects of climate, substrate, organisms, relief, and time in differentiating urban from non-urban areas, and for determining heterogeneity within spatially extensive metropolitan areas. In addition to reviewing key findings relevant to each state factor, we note the emergence of tentative "urban syndromes" concerning soils, streams, wildlife and plants, and homogenization of certain ecosystem functions, such as soil organic carbon dynamics. We note the utility of the ecosystem approach, the human ecosystem framework, and watersheds as integrative tools to tie information about multiple state factors together. The organismal component of urban complexes includes the social organization of the human population, and we review key modes by which human populations within urban areas are differentiated, and how such differentiation affects environmentally relevant actions. Emerging syntheses in land change science and ecological urban design are also summarized. The multifaceted frameworks and the growing urban knowledge base do however identify some pressing research needs.     

Neighbourhood characteristics and urban gardens in the Toledo metropolitan area: staffing and voluntarism,food production,infrastructure, and sustainability practices

Urban gardens are important sources of sustenance for communities with limited access to food. Hence, this study focuses on food production in gardens in the Toledo metropolitan area in Northwest Ohio. We administered surveys to 150 garden managers from November 2014 to February 2015 in our attempt to better understand how neighbourhood racial composition and poverty levels are related to staffing and voluntarism, food production and distribution, the development of infrastructure, and the adoption of sustainability practices in urban gardens. The results from 30 gardens are presented in this paper. We used Geographic Information Systems to map the gardens and overlay the map with 2010 census data so that we could conduct demographic analyses of the neighbourhoods in which the gardens were located. Though the gardens were small – two acres or less – up to 46 varieties of food were grown in a single garden. Gardens also operated on small budgets. Food from the gardens was gifted or shared with friends, family, and neighbourhood residents. Gardens in predominantly minority neighbourhoods tended to have fewer institutional partners, less garden infrastructure, and had adopted fewer sustainable practices than gardens in predominantly White neighbourhoods. Nonetheless, residents of predominantly minority and high-poverty neighbourhoods participated in garden activities and influenced garden operations. Volunteering and staffing were racialised and gendered.     

Predicting deer-vehicle collisions in an urban area

Collisions with deer and other large animals are increasing, and the resulting economic costs and risks to public safety have made mitigation measures a priority for both city and wildlife managers. We created landscape models to describe and predict deer-vehicle collision (DVCs) within the City of Edmonton, Alberta. Models based on roadside characteristics revealed that DVCs occurred frequently where roadside vegetation was both denser and more diverse, and that DVCs were more likely to occur when the groomed width of roadside right-of-ways was smaller. No DVCs occurred where the width of the vegetation-free or manicured roadside buffer was greater than 40 m. Landscape-based models showed that DVCs were more likely in more heterogeneous landscapes where road densities were lower and speed limits were higher, and where non-forested vegetation such as farmland was in closer proximity to larger tracts of forest. These models can help wildlife and transportation managers to identify locations of high collision frequency for mitigation. Modifying certain landscape and roadside habitats can be an effective way to reduce deer-vehicle collisions.     

Journalists' views of advertiser pressures on agricultural news

All major journalism ethical codes explicitly state that journalists should protect editorial copy from undue influence by outside sources. However, much of the previous research on agricultural information has concentrated on what information various media communicate (gatekeeping studies) or communication's role in increasing innovation adoption (diffusion studies). Few studies have concentrated specifically on organizational and structural constraints that might adversely affect agricultural journalists' ethical standards; those that have, focus largely on farm magazines. A study of newspaper reporters who cover agricultural news found that the most pressing ethical concern is the effect of advertiser (agri-business) pressure on editorial copy, and that their concerns in general parallel those of farm magazine writers and editors. The majority reported being in situations in which they might be exposed to advertiser pressure, including pressures to change or withhold editorial copy. Large minorities suggested that advertising pressures affect the overall environment in which agricultural journalists work, and more than one in ten said they allow advertiser pressures to influence editorial decisions. The newspaper reporters who cover agricultural beats showed slightly more resistance to advertiser pressure than did farm magazine editors in a parallel study.     

Definition Procedures Have Little Effect on Performance of Environmental Classifications of Streams and Rivers

Mapped environmental classifications are defined using various procedures, but there has been little evaluation of the differences in their ability to discriminate variation in independent ecological characteristics. We tested the performance of environmental classifications of the streams and rivers of France that had been defined from the same environmental data using geographic regionalization and numerical classification of individual river valley segments. Test data comprised invertebrate assemblages, water chemistry, and hydrological indexes obtained from sites throughout France. Classification performance was measured by analysis of similarity (ANOSIM). Geometric regions defined by a regular grid and without regard to environmental variables and a posteriori classifications based on clustering the test datasets defined lower and upper bounds of performance for a given number of classes. Differences in classification performances were generally small. The ANOSIM statistics for the a posteriori classifications were around twice that of all environmental classifications, including geometrically defined regions. The hydro-ecoregions performed slightly better for the invertebrate data and the network classification performed slightly better for the chemistry and hydrological data. Our results indicate that environmental classifications that are defined using different procedures can be comparable in terms of their ability to discriminate variation of ecological characteristics and that alleged differences in performance arising from different classification procedures can be small relative to unexplained variation. We conclude that definition procedures might have little effect on the performance of large-scale environmental classifications and decisions over which procedures to use should be based primarily on pragmatic considerations.     

Effect of Light on Biodegradation of Estrone, 17β‐Estradiol,and 17α‐Ethinylestradiol in Stream Sediment

Biodegradation of [A‐ring ¹⁴C] Estrone (E1), 17β‐estradiol (E2), and 17α‐ethinylestradiol (EE2) to ¹⁴CO₂ was investigated under light and dark conditions in microcosms containing epilithon or sediment collected from Boulder Creek, Colorado. Mineralization of the estrogen A‐ring was observed in all sediment treatments, but not epilithon treatments. No difference in net mineralization between light and dark treatments was observed for ¹⁴C‐E2. Net mineralization of ¹⁴C‐E1 and ¹⁴C‐EE2 was enhanced in light treatments. Extents of ¹⁴CO₂ accumulation and rates of mineralization were significantly greater for E2 than E1 under dark conditions, but were comparable under light conditions. These results indicate substantial differences in the uptake and metabolism of E1 and E2 in the environment and suggest biorecalcitrance of E1 relative to E2 in light‐limited environments. The extent of ¹⁴CO₂ accumulation and rate of mineralization for EE2 in dark treatments were less than half of that observed for E2 and generally lower than for E1, consistent with previous reports of EE2 biorecalcitrance. However, ¹⁴CO₂ accumulation and rates of mineralization were comparable for EE2, E2, and E1 under light conditions. These results indicate photoactivation and/or phototransformation/photodegradation processes can substantially enhance heterotrophic biodegradation of estrogens in sunlit environments and may play an important role in estrogen transport and attenuation.     

Bioremediation of Soils by Plant–Microbe Systems

Abstract

Sustainable ecosystems can be designed to eliminate environmental toxins and reduce pathogen loads through the direct and indirect consequences of plant and microbial activities. We present an approach to the bioremediation of disturbed environments, focusing on petroleum hydrocarbon (PHC) contaminants. Treatment consists of incorporating a plant-based amendment to enhance ecosystem productivity and physiochemical degradation followed by the establishment of plants to serve as oxidizers and foundations for microbial communities. Promising amendments for widespread use are entire plants of the water fern Azolla and seed meal of Brassica napus (rapeseed). An inexpensive byproduct from the manufacture of biodiesel and lubricants, rapeseed meal is high in nitrogen (6% wt/wt), stimulates >100-fold increases in populations of resident Streptomyces species, and suppresses fungal infection of roots subsequently cultivated in the amended soil. Synergistic enzymatic and chemical activities of plant and microbial metabolism in root zones transform and degrade soil contaminants. Emphasis is given to mechanisms that enable PHC functionalization via reactive molecular species.     

Provincial development plans in Zimbabwe: an analysis of their content,structure and methodology

Zimbabwean provincial plans were instituted to help in the achievement of the national goal of the creation of an egalitarian, socialist and integrated society. The national goal itself was adopted as an antithesis to the dualist society characterised by spatial, economic, social, politican and technological inequalities that Zimbabwe inherited from colonialism. This meant that provincial plans had to play both a functional (or growth allocating/distribution) and a territorial (or redistribution) role.

This paper reviews their role in achieving the national goal by examining their functions, content, structure and methodology. The paper concludes that because of their nature, provincial plans are not suitable tools for the achievement of the national goal.