"十二五"城镇污水处理厂环保投资效益分析

根据2011—2015年环境统计数据,分析了"十二五"期间城镇污水处理厂固定资产投资、环保投资效益等相关情况。研究发现,中国城镇污水处理厂在"十二五"期间固定资产投资和运行费用不断增加,污水处理能力不断提升,到2015年底,城镇污水处理厂共计5 390座,污水处理能力达17 169万t/d,实际污水处理量达到498.7亿t/a,COD和氨氮的去除量分别达到1 136.8万t和115.8万t。通过分析目前城镇污水处理厂在投资建设、运行维护等方面存在的问题,提出了相关建议,对今后城镇污水处理厂建设及运行起到指导作用。     

我国10万t/d以下城市污水处理工艺

我国城市污水处理厂的规模绝大多数在10万t/d以下(含10万t/d),由于10万t/d以下的城市污水处理的工艺繁多,且各有利弊,选择何种工艺对城市污水进行处理,是建设项目的业主、设计单位和主管政府部门较难解决但又必须解决的问题.本文从城市污水处理厂的处理工艺入手,根据国家的城市污水处理及污染防治技术政策,对10万t/d以下城市污水处理工艺进行排序和优选,并给出城市污水处理厂建设及运营的主要技术经济指标,供城市污水处理厂建设的相关方参考.     

中国城镇污水处理厂运行状况调查分析

根据问卷调查资料和抽样监测数据,分析了中国城镇污水处理厂的工艺水平、实际运行负荷、水质稳定性以及剩余污泥处理处置等方面的现状与问题.通过调查分析可知,近年来,中国的城镇污水处理事业得到了前所未有的发展,但城镇污水处理工作中也存在着一些明显不足,其主要表现为:(1)由于配套管网建设滞后和运行费用不足等问题,导致实际污水处理量未能与污水处理能力保持同步增长.近1/3数量的污水处理厂的运行负荷率低于70%,造成1/4以上的污水处理能力被闲置.(2)污水处理厂出水水质的稳定性普遍不高,一些传统的处理工艺则更差.(3)污泥不经脱水即随意外运、乱弃的现象已有很大改观,但绝大部分污泥都未经稳定化处理,更为严重的是仍有少部分污泥无任何处置措施.     

我国10万t／d以下城市污水处理工艺

我国城市污水处理厂的规模绝大多数在10万t／d以下（含10万t／d），由于10万t／d以下的城市污水处理的工艺繁多，且各有利弊，选择何种工艺对城市污水进行处理，是建设项目的业主、设计单位和主管政府部门较难解决但又必须解决的问题。本文从城市污水处理厂的处理工艺入手，根据国家的城市污水处理及污染防治技术政策，对10万t／d以下城市污水处理工艺进行排序和优选，并给出城市污水处理厂建设及运营的主要技术经济指标，供城市污水处理厂建设的相关方参考。     

广西城镇污水处理厂建设和运行的现状分析

全区108座污水处理厂建设规模、工艺、投资和运行成本统计表明,广西城镇污水处理厂以小型污水处理厂为主,处理工艺多采用氧化沟、A2/O、SBR及其变种工艺;5～10万m3/d规模污水处理单位建设投资以氧化沟、A2/O、SBR及其变种工艺较省,2～5万m3/d规模以氧化沟、MSBR工艺较省,2 m3/d以下规模以硅藻土、人工湿地和人工快渗工艺较为经济;2～10万m3/d规模污水处理厂各工艺运行成本多介于0.3～0.4元/m3,2万m3/d以下规模人工快渗和人工湿地工艺的运行费用介于0.2～0.3元/m3。不同规模、不同工艺、不同排放标准污水处理厂的投资建设、运行成本和出水水质各异,因此,污水处理厂应因地制宜选择适宜工艺技术、规模及排放标准,有效提高设施运行负荷率和污染物的去除率。     

广西农村连片整治的污水处理现状、问题及其对策

2011年广西确定了漓江流域、桂中红水河流域、桂东南西江流域、北部湾沿海地区作为农村环境连片整治示范区。2012年和2013年上述4个连片整治示范区共建设农村污水处理设施487和566套,累计建设规模36 995和33 740m3/d,单池建设规模多小于150 m3/d规模;采用工艺以厌氧-缺氧-好氧生物接触氧化(含一体化)-人工湿地工艺为主,且该工艺单位建设投资相对较省;已验收设施出水水质达到建设要求,取得了较好的治理效果。但同时也暴露顶层设计不够、没有制定设施运行管理细则等问题,对此提出了针对性对策。     

江苏省污水处理设施运营市场化探讨

简述江苏污水处理设施运营市场化的形式，分析江苏污水处理设施运营市场化现状，从宣传教育、准入制度、政策法规、管网建设等方面提出了建议。     

贵州省已建城镇污水处理厂建设及运行状况

"十一五"期间,贵州省开展了大规模的城镇污水处理厂建设,主要采用了以氧化沟、A/O工艺和SBR及改良工艺等具有脱氮除磷功能、技术成熟的工艺,建设规模多在0.5万m3/d以下,单位平均建设投资4 069.75元/m3,单位综合能耗平均0.35 k Wh/m3,单位平均药耗0.41 g/m3,单位运行成本多在0.60元/m3以上,污水平均处理率82.01%,平均处理负荷率73.19%,处理出水基本达到城镇污水处理厂污染物排放标准(GB18918-2002)一级B标准的要求,取得了较好的减排效果,但部分污水处理厂存在工艺技术的匹配性等问题,建议"十二五"期间加强已建污水处理厂工艺技术和设施的改造升级。     

北方城市垃圾渗滤液水量水质变化特征

研究了垃圾卫生填埋场渗滤液的年产量、夏季产量及其与填埋场规模、运行年限之间的关系。分析了填埋场夏季渗滤液的COD、BOD5、氨氮、p H值和BOD5/COD规律。研究结果表明,渗滤液年产量与填埋场规模、运行年限有关。渗滤液夏季产量变化规律与其相应的年产量并不一致。规模M≤100 t/d、100M≤200 t/d、200M≤500 t/d和M500 t/d的填埋场夏季渗滤液产量呈现出不同的变化特征。各填埋场的夏季渗滤液水质差别较大,COD值总体偏小,处于35.5~3 029.8 mg/L之间;BOD5值处于6.5~1 120.7 mg/L之间;64.2%的填埋场夏季渗滤液的BOD5/COD值≥0.30,可生化性较好;氨氮为21~1 273 mg/L。研究结果可为国内城市垃圾卫生填埋场渗滤液处理工作提供参考。     

瑞典市政污水处理的管理措施及启示

随着中国市政污水处理厂建成率不断提高,如何对污水处理厂所排放的污染物实施有效管理,避免其对环境造成"二次污染",成为亟待解决的问题。瑞典经济发达,自然环境优美,其在加强市政污水处理的相关立法、提升市政污水处理能力、控制市政污水处理厂氮磷排放以及污泥中有毒有害物质方面理念先进,成效显著。对比中国市政污水处理及污染物排放管理现状,瑞典的做法和经验值得中国思考和借鉴。     

Evaluation of trichloroethene recovery processes in heterogeneous aquifer cells flushed with biodegradable surfactants

The ability of two biodegradable surfactants, polyoxyethylene (20) sorbitan monooleate (Tween 80) and sodium dihexyl sulfosuccinate (Aerosol MA), to recover a representative dense non-aqueous-phase liquid (DNAPL), trichloroethene (TCE), from heterogeneous porous media was evaluated through a combination of batch and aquifer cell experiments. An aqueous solution containing 3.3% Aerosol MA, 8% 2-propanol and 6 g/l CaCl(2) yielded a weight solubilization ratio (WSR) of 1.21 g TCE/g surfactant, with a corresponding liquid-liquid interfacial tension (IFT) of 0.19 dyn/cm. Flushing of aquifer cells containing a TCE-DNAPL source zone with approximately two pore volumes of the AMA formulation resulted in substantial (>30%) mobilization of TCE-DNAPL. However, a TCE mass recovery of 81% was achieved when the aqueous-phase flow rate was sufficient to displace the mobile TCE-DNAPL toward the effluent well. Aqueous solutions of Tween 80 exhibited a greater capacity to solubilize TCE (WSR=1.74 g TCE/g surfactant) and exerted markedly less reduction in IFT (10.4 dyn/cm). These data contradict an accepted empirical correlation used to estimate IFT values from solubilization capacity, and indicate a unique capacity of T80 to form concentrated TCE emulsions. Flushing of aquifer cells with less than 2.5 pore volumes of a 4% T80 solution achieved TCE mass recoveries ranging from 66 to 85%, with only slight TCE-DNAPL mobilization (<5%) occurring when the total trapping number exceeded 2 x 10(-5). These findings demonstrate the ability of Tween 80 and Aerosol MA solutions to efficiently recover TCE from a heterogeneous DNAPL source zone, and the utility of the total trapping number as a design parameter for a priori prediction of DNAPL mobilization and bank angle formation when flushing with low-IFT solutions. Given their potential to stimulate microbial reductive dechlorination at low concentrations, these surfactants are well-suited for remedial action plans that couple aggressive mass removal followed by enhanced bioremediation to treat chlorinated solvent source zones.     

The variation of street air levels of PAH and other mutagenic PAC in relation to regulations of traffic emissions and the impact of atmospheric processes

The occurrence of particle associated PAH and other mutagenic PAC was determined in 1996 in the street air of Copenhagen. In addition, particle extracts were tested for mutagenicity. The measurements were compared with previous measurements in 1992/1993. The levels had decreased in this period. The decrease was caused by an implementation of light diesel fuels for buses and the exchange of older petrol-driven passenger cars with catalystequipped new ones. About 65% of the reduction was caused by the application of the light diesel fuels. Under special conditions, chemical processes in the atmosphere produced many more mutagens than the direct emissions. The concentrations of S-PAC and N-PAC were 10 times lower than those of PAH, while the levels of oxy-PAH were in the same order of magnitude as those of PAH. Benzanthrone, an oxy-PAH, is proposed to be formed in the atmosphere in addition to direct emissions. Benzo(a)pyrene, often applied as an air quality criteria indicator, was photochemically degraded in the atmosphere. A strong increase in the mutagenic activities was observed to coincide with a depletion of benzo(a)pyrene.     

Chloroaromatic pollutants in mussels incubated in two finnish watercourses polluted by industry

Concentrations of different chlorinated compounds were measured in mussels incubated in two polluted watercourses, a river (the River Kymijoki) and a lake (Lake Vanaja) for four weeks in summer 1995. The sum concentrations of polychlorinated phenols (PCP) and biphenyls (PCB) were both about 1 μg/g lipid weight (lw) in Lake Vanaja mussels, while in the River Kymijoki mussels PCPs were non-detectable and PCBs were measured 120 ng/g lIw. The concentrations of toxic polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners ranged between <17 and 370 pg/g Iw in Lake Vanaja mussels and between <38 and 11,000 pg/g lw in the River Kymijoki mussels. Polychlorinated diphenyl ethers (PCDE) were detected in the mussels incubated in the River Kymijoki (0.4–1.1 ng/g Iw), but not in those incubated in Lake Vanaja. Polychlorinated phenoxyanisoles (PCPA) were measured 33 ng/g lw and polychlorinated phenoxyphenols (PCPP) 300 ng/g lw in the mussels incubated in the River Kymijoki. PCPAs were also detected in reference samples, which were sediment and pike from the River Kymijoki and Baltic salmon, seal and white-tailed sea eagle.     

Teratological effects of pesticides in vertebrates: a review

Abstract

In the last decades, the use and misuse of pesticides in the agriculture have increased, having a severe impact on ecosystems and their fauna. Although the various effects of pesticides on biodiversity have been already documented in several studies, to our knowledge no consistent overview of the impact of pesticides in vertebrates, both terrestrial and aquatic, is available. In this review, we try to present a concise compilation of the teratogenic effects of pesticides on the different classes of vertebrates – mammals, birds, reptiles, amphibians and fish.     

Radionuclides and trace elements in fish collected upstream and downstream of Los Alamos national laboratory and the doses to humans from the consumption of muscle and bone

Abstract

The purpose of this study was to determine radionuclide and trace element concentrations in bottom‐feeding fish (catfish, carp, and suckers) collected from the confluences of some of the major canyons that cross Los Alamos National Laboratory (LANL) lands with the Rio Grande (RG) and the potential radiological doses from the ingestion of these fish. Samples of muscle and bone (and viscera in some cases) were analyzed for ³H, ⁹⁰Sr, ¹³⁷Cs, ^totU, ²³⁸Pu, ^239,240Pu, and ²⁴¹Am and Ag, As, Ba, Be, Cr, Cd, Cu, Hg, Ni, Pb, Sb, Se, and Tl. Most radionuclides, with the exception of ⁹⁰Sr, in the muscle plus bone portions of fish collected from LANL canyons/RG were not significantly (p<0.05) higher from fish collected upstream (San Ildefonso/background) of LANL. Strontium‐90 in fish muscle plus bone tissue significantly (p<0.05) increases in concentration starting from Los Alamos Canyon, the most upstream confluence (fish contained 3.4E‐02 pCi g^‐1 [126E‐02 Bq kg^‐1]), to Frijoles Canyon, the most downstream confluence (fish contained 14E‐02 pCi g^‐1 [518E‐02 Bq kg^‐1]). The differences in ⁹⁰Sr concentrations in fish collected downstream and upstream (background) of LANL, however, were very small. Based on the average concentrations (±2SD) of radionuclides in fish tissue from the four LANL confluences, the committed effective dose equivalent from the ingestion of 46 lb (21 kg) (maximum ingestion rate per person per year) of fish muscle plus bone, after the subtraction of background, was 0.1 ± 0.1 mrem y^‐1 (1.0 ± 1.0 μSv y^‐1), and was far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem y^‐1 (1000 μSv y^‐1). Of the trace elements that were found above the limits of detection (Ba, Cu, and Hg) in fish muscle collected from the confluences of canyons that cross LANL and the RG, none were in significantly higher (p<0.05) concentrations than in muscle of fish collected from background locations.     

Book review

The Pesticide Manual ‐ A World Compendium, 8th Edition, C.R. Worthing, Editor and S.B. Walker, Assistant Editor, British Crop Protection Council, BCPC Publications Sales, Bear Farm, Binfield, Bracknell, Berkshire RG12 5QE, England. 1987, 1100 pp., UK £50; Overseas £56. ISBN 0–948404–01–9.     

Patterns of volatile metabolites and nonvolatile trichothecenes produced by isolates of <Emphasis Type="Italic">Stachybotrys,Fusarium, Trichoderma,Trichothecium</Emphasis> and <Emphasis Type="Italic">Memnoniella</Emphasis>

We reported previously that trichodiene, a volatile trichothecene derivative, was produced by a Stachybotrys isolate, also known to produce highly cytotoxic, non-volatile, macrocyclic trichothecenes (satrotoxins). We investigated the relationship between the production of trichodiene and various non-volatile trichothecenes for several molds. Volatile metabolites were concentrated by adsorption on Tenax TA and analyzed by GC/MS, while non-volatile metabolites were separated by HPLC, derivatized and analyzed by GC/MS. Stachybotrys chartarum isolates producing macrocyclic trichothecenes secreted significantly larger amounts of trichodiene and other sesquiterpenes than isolates which only produced simple trichothecenes. The amounts of secreted trichodiene were relatively small in all cases. With the exception of Memnoniella, which excreted small amounts of sesquiterpenes, the other isolates produced varying amounts of sesquiterpenes, including trichodiene, as well as simple tricothecenes, no detectable trichodiene, but large amounts of griseofulvin derivatives. In Stachybotrys there is apparently a correlation between trichodiene and macrocyclic trichothecene production. In the remaining isolates, there was no simple relationship between trichodiene and non-volatile trichothecene synthesis. Trichodiene is produced in larger amounts by Stachybotrys isolates, which also produce satratoxins, but it will be difficult to utilize this metabolite to detect toxic isolates in buildings due to the relatively small amounts excreted.     

Knowledge transfer initiative between molecular biologists and environmental researchers and regulators

A Natural Environment Research Council (NERC) funded Knowledge Transfer (KT) workshop was held in the United Kingdom (UK) to identify the needs and opportunities in the application of molecular biology and ‘omics’ techniques to environmental monitoring and risk assessment. Attendees highlighted a lack of effective communication between end-users and researchers as well as difficulties with data interpretation as reasons behind the slow uptake of molecular biology and omics techniques. A number of promising areas in which new techniques could be implemented at a practical level in the very near future were identified, thereby raising the profile of these recent technologies and providing vital proof of concept work. Molecular taxonomy, bacterial source tracking and pre-screening of chemicals for potential toxicities were all viewed as areas in which omics and molecular techniques could have immediate value, with the aim of reducing cost, increasing efficiency and providing more comprehensive data of improved quality.     

The chemical stability of formulations of some hydrolyzable insecticides in aqueous mixtures with hydrolysis catalysts

Abstract

The active ingredients in commercial formulations of malathion, oxamyl, carbaryl, diazinon, and chlorpyrifos diluted to “spray tank”; concentrations with buffered distilled or natural water of pH 4–9 were stable for at least 24 hr. Formulations of trichlorfon were not stable at pH 7 or above but disappearance rates were slower than for the pure chemical in homogeneous solution. Cupric ion was observed to be an effective catalyst for the hydrolysis of a variety of pure organophosphorus insecticides but did not catalyze hydrolysis of the active ingredients of the formulations examined. Increasing the dilution of the formulation increased the susceptibility of malathion, oxamyl, and carbaryl to hydrolysis.     

Organochlorine compounds in a three-step terrestrial food chain

The concentrations of 15 organochlorine chemicals (PCBs and pesticides) were studied in a Central European oak wood food chain system: Great tit (Parus major), caterpillars (Tortrix viridana, Operophtera brumata, Erannis defoliaria), and oak-leaves (Quercus robur). Juvenile tits receive organochlorines from the mother via egg transfer and, eventually to a greater extent, from the caterpillar food source during nestling period. The concentrations of PCB 153 (2,2′,4,4′,5,5′-hexachlorobiphenyl, the most abundant in this study) was found in leaf material at ca. 1 ng/g, in caterpillars 10 ng/g, and in bird eggs 170 ng/g on an average and on a dry mass basis.