基于公私合营管理模式在城市生活垃圾处理中的应用研究

提出基于公私合营的政府管理模式在城市生活垃圾处理中的应用研究,对公私合营的政府管理模式具有的"伙伴关系、利益共享、风险共担"三大特征进行了分析;借鉴当前学术界存在的一些公私合营的政府管理模式类型,与城市生活垃圾治理的行业特征进行有机结合,将公私合营的政府管理模式分为公有私营模式、公私合资模式和特许经营模式三大类,分析这些模式在城市生活垃圾处理中的具体应用,实现政策性与效益性的双赢发展机制,对改善城市居民生活环境,促进城市经济和社会的高质量发展具有重要意义。     

我国垃圾处理领域PPP发展及其改革方向探讨

随着城市经济和人口的快速增长,城市垃圾数量与日俱增,影响了生态环境和城市的可持续发展。垃圾焚烧是缓解城市垃圾压力的重要手段,而推进垃圾治理,仅靠政府治理显然不够。文章指出PPP对于推进垃圾治理具有积极意义,在分析我国垃圾处理领域PPP进展现状的基础上,提出了未来垃圾处理领域PPP的改革方向和路径。     

昆明城市生活垃圾处理产业发展的SWOT分析研究

随着城市化进程的深入,生活垃圾问题日益突出,城市生活垃圾处理产业的发展是解决“垃圾围城”困境的有效途径.昆明城市生活垃圾处理产业处于发展阶段,运用态势分析法(SWOT),系统地对昆明城市生活垃圾处理产业发展的优势、劣势、所存在的机会和威胁进行分析,并提出相应发展对策,包括完善生活垃圾处理.产业的经济激励机制;采用多种项目融资模式进行生活垃圾产业建设融资;加快静脉产业园区建设发展;打造再生资源回收利用的龙头企业;积极控制生活垃圾源头;建立垃圾排放权交易等.     

公私合作,共建宜居城市

正哥本哈根市近些年取得的成就,在很大程度上归功于一个词:"共建"或者说"公私合作"。"公私合作"在丹麦到底是什么意思?公私合作"公私合作"(英文为Public and Private Partnership,简称是PPP或是3P)并不是一个新概念,具体含义也并不统一。以近些年来欧洲多个国家和城市践行"公私合作"的经验来看,     

农村生活垃圾治理PPP模式研究——以安徽省全椒县为例

目前我国农村生活垃圾治理供需矛盾突出,成为影响乡村振兴战略进程的重要问题。政府和社会资本合作(PPP)模式被视为破解农村生活垃圾治理困境的有力手段,国家陆续多部政策文件加以扶持引导。本文以安徽省全椒县为例,阐述农村生活垃圾治理项目PPP模式取得成效及存在问题,并提出相关对策建议,以期为其他地区提高农村生活垃圾治理水平提供借鉴。研究指出,为完善农村生活垃圾处理PPP模式,引导农村生活垃圾治理行业健康发展,提高农村生活垃圾治理质量和效率,建议如下:(1)推动垃圾分类和资源化利用产业发展,降低末端处理压力;(2)保障第三方企业获得合理的投资回报,保持市场活力;(3)充分调动村民积极性,培育多元市场主体。     

落实生活垃圾收费制度是促进城市垃圾产业化的重大举措

为根本改变城市生活垃圾处理滞后状况,我国政府已推进垃圾处理机制创新和改革.生活垃圾收费制度将把多年垃圾处理这项公益事业转为产业,将由政府包办变为全社会来办.收费制度的出台,将给城市垃圾处理产业注入活力.     

循环经济与城市居民生活垃圾处理收费模式选择的分析

以循环经济思想及其操作原则分析比较了国外现有的3种城市居民生活垃圾处理收费模式的优缺点。指出了从量收费模式在促进城市生活垃圾处理上的优势。研究中发现。我国目前已经实行城市生活垃圾处理收费制度的城市都采取定额收费模式。提出选择从量收费是我国城市居民生活垃圾处理收费制度的主要设计方向。     

基于环保基础设施PPP项目风险分担研究

公私合作模式（PPP）是解决环保基础设施建设资金紧张以及政府在基础设施管理上效率底下的一个有效的方式。风险分担是环保基础设施PPP项目融资模式的核心问题之一,由于其组织结构复杂,导致在操作过程中会产生一系列的风险。不合理的风险分担不仅会增加项目总成本,甚至会导致项目的失败。文章基于委托代理理论,构建了投资者和运营商之间的最优风险分担比例模型。为现实的实际操作提供了一种有效思路。     

中国城市生活垃圾处理的投资方式调研

编者按 改革开放以后,随着城市生活水平的提高,生活垃圾产生量不断增加,垃圾围城现象日益严重;同时,大量随意堆放垃圾所带来的恶臭、滋生大量的蚊、蝇和病原微生物严重影响着人体健康.随着国家对环境保护工作重视的加强,城市生活垃圾处理也被纳入了各级政府环境污染治理的工作之中."九五"以来,我国城市生活垃圾处理领域作为环境保护的重要一环真正被提上了国家议程.在近几年,借助"后发优势",受国际上生活垃圾处理领域的技术转型即向资源回收再利用循环型社会方向发展这一理念的影响与启发,垃圾的收集与处理方式在系统层面有更大的调整,即在采用最终无害化处理方法之前,应尽量促进废物减量化、重复和循环使用,符合循环经济理念的新的技术选择与投资将会立于不败之地.我国的城市生活垃圾处理相关设施建设需要统筹、系统地考虑无害化和资源化的问题,最终目标是建设清洁、卫生、美好的环境和资源节约型社会.本文对我国城市生活垃圾处理的投资方式进行调研,以求为城市生活垃圾处理设施建设与运营的进一步发展提供理论依据.     

我国城市生活垃圾产业最优模式设计

通过对垃圾产业市场的分析，阐述了我国城市生活垃圾产业的历史、现状和存在的问题。在此基础上，根据我国的实际情况，提出了适合于我国城市生活垃圾产业系统的最优模式：垃圾生产子系统、垃圾分类收集子系统和垃圾最终处理与资源化利用子系统。提出居民初步分类与政府组织下的“拾荒者合作社”精细分类相结合，按照处理技术的不同，将城市生活垃圾分成5种类型。通过对各类型生活垃圾流向的系统设计，保证了城市生活垃圾处理的减量化、资源化和无害化。最后讨论了政府在垃圾产业最优模式形成过程中的作用，并提出政府可以借鉴的城市生活垃圾产业管理措施12项。     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

Removal of cadmium using MnO2 loaded D301 resin

MnO2 loaded weak basic anion exchange resin D301 （Anion exchange resin, macroreticular weak basic styrene） as adsorbent has been prepared and applied to the removal of cadmium. The adsorption characteristics have been investigated with respect to effect of pH, equilibrium isotherms, removal kinetic data, and interference of the coexisting ions. The results indicated that the Cd^2＋ could be efficiently removed using MnO2 loaded D301 resin in the pH range of 3-8 from aqueous solutions with the co-existence of high concentration of alkali and alkaline-earth metals ions. The saturate adsorption capacity of the Cd^2＋ was 77.88 mg/g. The adsorption process followed the pseudo first-order kinetics. The equilibrium data obtained in this study accorded excellently with the Langmuir adsorption isotherm.     

Effect of coagulation pretreatment on the fouling of ultrafiltration membrane

The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）. A relatively higher molecular weight （MW） of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.     

Penetration analysis of elements and bioleaching treatment of spent refractory for recycling

Acidithiobacillus ferrooxidans ATCC23270 and Acidithiobacillus thiooxidans TM-32 were used for bioleaching of spent refractories of aluminium and copper melting furnaces for their recycling.Firstly,penetration of elements into aluminium melting furnace refractory was investigated and it was found that up to 7 cm from surface was contaminated.Comparison on leaching efficiency by the strains ATCC23270 and TM-32 found that the strain ATCC23270 could treat larger amount of the refractories than the strain TM-32 could do.In the experiment of bioleaching of spent refractory aluminium melting furnace by the strain ATCC23270,high leaching efficiency were obtained on Al,Si,and Ca,and extremely low leaching performance was,however,shown on the rest of elements i.e.,Na,Mn,and Zn.Under the strain TM-32 use,relatively high leaching performance was recognized on Al,Si,Ca,Na,Mn,and Zn.In the experiment of bioleaching for spent refractory copper melting furnace,almost the same leaching trends were shown on Cu,Zn,Al,and Si under the strains ACTT23270 and TM-32 uses.     

Simultaneous removal of ammonium and phosphate by zeolite synthesized from coal fly ash as influenced by acid treatment

Zeolite synthesized from fly ash （ZFA） without modification is not efficient for the purification of NH4＋ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacity. To develop an effective technique to enhance the removal efficiency of ammonium and phosphate at low concentrations, ZFA was modified with acid treatment and the simultaneous removal of ammonium and phosphate in a wide range of concentration was investigated. It was seen that when compared with untreated ZFA, only the treatment by 0.01 mol/L of H2SO4 significantly improved the removal efficiency of ammonium at low initial concentrations. The behavior was well explained by the pH effect. Treatment by more concentrated H2SO4 led to the deterioration of the ZFA structure and a decrease in the cation exchange capacity. Treatment by 0.01 mol/L H2SO4 improved the removal efficiency of phosphate by ZFA at all initial P concentrations, while the treatment by concentrated H2SO4 （≥0.9 mol/L） resulted in a limited maximum phosphate immobilization capacity （PIC）. It was concluded that through a previous mild acid treatment （e.g. 0.01 mol/L of H2SO4）, ZFA can be used in the simultaneous removal of NH4＋ and P at low concentrations simulating real effluent.