Phosphorus accumulation by bacteria isolated from a ontinuous-flow two-sludge system

In this article, polyphosphate-accumulating organisms （PAOs） from a lab-scale continuous-flow two-sludge system was isolated and identified, the different phosphorus accumulation characteristics of the isolates under anoxic and aerobic conditions were investigated. Two kinds of PAOs were both found in the anoxic zones of the two-sludge system, one of them utilized only oxygen as electron aeceptor, and the other one utilized either nitrate or oxygen as electron aeceptor. Of the total eight isolates, five isolates were capable of utilizing both nitrate and oxygen as electron acceptors to uptake phosphorus to some extent. And three of the five isolates showed good phosphorus accumulative capacities both under anoxic or aerobic conditions, two identified as Alcaligenes and one identified as Pseudomonas. Streptococcus was observed weak anoxic phosphorus accumulation because of its weak denitrification capacity, but it showed good phosphorus accumulation capacity under aerobic conditions. One isolates identified as Enterobacteriaceae was proved to be a special species of PAOs, which could only uptake small amounts of phosphorus under anoxic conditions, although its denitrification capacity and aerobic phosphorus accumulation capacity were excellent.     

农村环境善治的逻辑重塑——基于利益相关者理论的分析

农村环境污染问题是我国实现十八届五中全会倡导的五位一体重大战略的突出矛盾,也是学术界需要研究的核心问题之一。本研究利用利益相关者理论分析法,对我国农村环境治理失灵的内在机理进行理论解释,认为政府、企业、城市、村民、环保组织、科研院校等利益相关者的不同利益诉求和行为导向,造成了目前农村环境污染的现实困境。分析发现:正是政府层面重视经济发展,轻视监管职责;企业层面重视经济利润,轻视社会责任;农民层面重视生计诉求、轻视安全需求;城市层面突破政府管制,转嫁污染成本;环保组织力量资源有限,难以提供环保功能以及科研院校重视环保技术研发,轻视科技推广,才导致了现阶段农村环境污染愈演愈烈。因此,只有明确政府、企业、城市、村民、环保组织、科研院校等利益相关者的角色定位,充分发挥好各自的环保功能,真正构建起农村环境的共同治理体系,才能克服不同利益相关者之间的冲突和相互博弈状态,进而实现农村环境善治的目标。研究结论表明:农村环境善治的内涵体现为政治国家与公民社会的合作参与、共同治理乡村环境问题.其主要特征为合法性、透明性、责任性、回应性、有效性,其实质是在乡村环境治理中,构建起强国家和强社会的"双强"模式。通过构建这种"双强"模式使国家与社会在乡村环境治理中达成利益均衡共识,彼此协同合作,共同致力于乡村环境的善治之道,以此彻底改变现在的乡村污染面貌,最终实现十八届五中全会倡导的生态良好农村战略构想。     

Removal of heavy metals from aqueous solution by sawdust adsorption

The adsorption of lead, cadmium and nicel from aqueous solution by sawdust of walnut was investigated. The effect of contact time, initial metal ion concentration and temperature on metal ions removal has been studied. The equilibrium time was found to be of the order of 60 min. Kinetics fit pseudo first-order, second-order and intraparticle diffusion models, hence adsorption rate constants were calculated. The adsorption data of metal ions at temperatures of 25, 45 and 60~C have been described by the Freundlich and Langmuir isotherm models. The thermodynamic parameters such as energy, entropy and enthalpy changes for the adsorption of heavy metal ions have also been computed and discussed. Ion exchange is probably one of the major adsorption mechanisms for binding divalent metal ions to the walnut sawdust. The selectivity order of the adsorbent is Pb（I1）~Cd（II）〉Ni（I1）. From these results, it can be concluded that the sawdust of walnut could be a good adsorbent for the metal ions from aqueous solutions.     

Transfer and transport of aluminum in filtration unit

Aluminum salt coagulants were used prevalently in various water works.In this article,the effects of filtration on residual aluminum concentration and species distribution were researched by determining the concentration of diiferent aluminum species before and after single layer filter,double layer filter,and membrane filtration units.In the research,size exclusion chromatography(SEC)was used to separate colloidal and soluble aluminum,ion exchange chromatography(IEC)was used to separate organic and inorganic aluminum, and inductivity coupled plasma-atomic emission spectrometry(ICP-AES)was used to determine the aluminum concentration.The results showed that the rapid filtration process had the ability of removing residual aluminum from coagulant effluent water,and that double layer filtration was more effective in residual aluminum removal than single layer filtration,while nano filtration was more effective than micro filtration.It was found that when the residual aluminum concentration was below 1mg/L in sediment effluent,the residual aluminum concentration in treated water was above 0.2 mg/L.The direct rapid filtration process mainly removed the suspended aluminum.The removal of soluble and colloidal aluminum was always less than 10% and the natural small particles that adsorbed the amount of soluble or small particles aluminum on their surface were difficult to be removed in this process.Micro filtration and nano filtration were good technologies for removing aluminum;the residual aluminum concentration in the effluent was less than 0.05 mg/L.     

Comparing results of cultured and uncultured biological methods used in biological phosphorus removal

Increasing attention has been paid to phosphate-accumulating organisms(PAOs)for their important role in biological phosphorus removal.In this study,microbial communities of PAOs cultivated under different carbon sources(sewage,glucose,and sodium acetate) were investigated and compared through culture-dependent and culture-independent methods,respectively.The results obtained using denaturing gradient gel electrophoresis(DGGE)of polymerase chain reaction-amplified 16S rDNA fragments revealed that the diversity of bacteria in a sewage-fed reactor(1#)was much higher than in a glucose-fed one(2#)and a sodium acetate-fed one(3#);there were common PAOs in three reactors fed by different carbon sources.Five strains were separated from three systems by using a phosphate- rich medium;they were from common bacteria isolated and three isolates could not be found in DGGE profile at all.Two isolates had good phosphorus removal ability.When the microbial diversity was studied,the molecular biological method was better than the culture-dependent one.When phosphorus removal characteristics were investigated,culture-dependent approach was more effective. Thus a combination of two methods is necessary to have a comprehensive view of PAOs.     

Removal of heavy metals using waste eggshell

The removal capacity of toxic heavy metals by the reused eggshell was studied.As a pretreatment process for the preparation of reused material from waste eggshell,calcination was performed in the furnace at 800℃for 2 h after crushing the dried waste eggshell.Calcination behavior,qualitative and quantitative elemental information,mineral type and surface characteristics before and after calcination of eggshell were examined by thermal gravimetric analysis(TGA),X-ray fluorescence (XRF),X-ray diffraction(XRD) and scanning electron microscopy(SEM),respectively.After calcination,the major inorganic composition was identified as Ca(lime, 99.63%)and K,P and Sr were identified as minor components.When calcined eggshell was applied in the treatment of synthetic wastewater containing heavy metals,a complete removal of Cd as well as above 99% removal of Cr was observed after 10 min. Although the natural eggshell had some removal capacity of Cd and Cr,a complete removal was not accomplished even after 60 min due to quite slower removal rate.However,in contrast to Cd and Cr,an efficient removal of Pb was observed with the natural eggshell rather than the calcined eggshell.From the application of the calcined eggshell in the treatment of real electroplating wastewater, the calcined eggshell showed a promising removal capacity of heavy metal ions as well as had a good neutralization capacity in the treatment of strong acidic wastewater.     

旅行社品牌经营中必须注意的几个问题--兼论安徽省旅行社的品牌经营

我国旅行社业正经历着激烈的市场竞争,许多旅行社开始注重打造品牌,但旅行社品牌经营现状令人堪忧.结合安徽省旅行社的实际,剖析了旅行社品牌经营状况,并就品牌经营过程中存在的问题和如何进行品牌经营提出了自己的看法,以期对旅行社经营管理者有一定的借鉴作用.     

The (un)common good: diverging justifications for wilderness making in a modified landscape

ABSTRACT

Wilderness is most often conceived as comprising large remote areas where evidence of human influence is slight. Little attention has been afforded to the study of wilderness ‘making’ in smaller landscapes that have been heavily modified by human activity. This paper addresses this knowledge deficit by employing the pragmatic sociology of Boltanski and Thévenot to analyse a case study of wilderness making in the west of Ireland. The application of this framework illustrates how contending positions on ‘why’ wilderness making should occur and ‘how’ it should be conducted reflect ethical frameworks rooted in different conceptions of the ‘common good’ presented by the idea of wilderness. The paper demonstrates the difficulties with developing such a new nature-based concept in the absence of conventional (received) ideas of wilderness by revealing how the diverging justifications used suggest incommensurability in the competing notions of wilderness that are formulated and advanced.     

Measuring good governance: piloting an instrument for evaluating good governance principles

ABSTRACT

As federal, state, and local governments and agencies respond to calls to make decisions and implement programs according to tenets of ‘good governance’, a need exists to develop methods for systematically evaluating performance. ‘Good governance’ has been characterized as including a wide array of principles, which vary across literatures. Comparatively little scholarship has sought to systematically quantify program achievement in accordance with these principles. We develop and present a scale for measuring program achievement in accordance with eight main principles of good governance: inclusivity, fairness, transparency, accountability, legitimacy, direction, performance, and capability. We present the results of a pilot implementation of the scale within the context of two community-based deer management programs. Our results suggest that these principles of good governance may not sort into distinct dimensions in a real-world context.     

Water as an economic good

There has been much debate in recent years about whether or not water should be regarded as an 'economic good', and, if so, what this implies. This paper discusses both water resources in general and the more specific issue of domestic water supply within the context of current debates on sustainable development. It addresses some practical and some more philosophical aspects of the matter, and how these relate to the concerns of different international organisations involved in the sector. It argues that water should be regarded as an economic good, but in a broad rather than a narrow, 'economistic' sense.