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1.
乐清市城北乡地处乐清市北部山区,东连北雁荡山,西邻中雁荡山,南距乐清市区6.4 km,北接永嘉楠溪江,乡域面积42.7 km2,平均海拔449m,辖17个行政村,总人口11086人。2005年,全乡国内生产总值3.12亿元,工业总产值3亿元,农业总产值0.2亿元,农民人均收入3151元。城北乡处处山青水秀,景色宜人,气候温和,特产繁多,是游览、避暑、休养的佳境,素有乐清市的“后花园”之称,有着丰富的自然和人文资源。境内有温州市级风景名胜区灵山景区,因其生态环境和谐优美,2004年底被张纪中导演的《神雕侠侣》摄制组选为外景地。近几年,城…  相似文献   

2.
SBR法的特点及其在生物脱氮中的应用   总被引:8,自引:3,他引:8  
SBR兼有全混合反应器与推流式反应器的优点,物料混合均匀,耐冲击负荷,不存在物料返混,生化反应动力大,处理好,SBR法的整个过程可放置于一个构筑物内完成,工艺简单,操作灵活,此外,通过对SBR的适当调控,易形成好氧/缺氧交替的环境,为生物脱氮创造条件,近年来,SBR法得到了较大的发展,操作方式也得很大的改进。  相似文献   

3.
燃煤倒焰窑烟尘治理,因其本身结构特点,若单纯采用末端治理,则投资大,治理效果不稳定,在治理上存在一定难度。通过实践,采用炉头增氧,尾部喷淋的治理工艺可以达到好的治理效果,而且投资少,工期短,运行费用低,易于操作。  相似文献   

4.
互联网与环境科学技术   总被引:2,自引:0,他引:2  
互联网的普及对推动环境科学技术发展起着很大作用,一方面,全理利用网络的资源可以使科研工作事半功倍,另一方面,互联网逐渐成为环境技术的推广应用,环保设备产品宣传和销售中的重要环节,本文介绍与环境科学技术相关的网络资源,包括文献检索,软件和环境科学讨论组,数据库,环保技术设备信息平台等。  相似文献   

5.
自改革开放以来,浙江省的环境保护工作取得了很大的进展,工业污染得到一定程度的控制,城市环境综合整治效果显著,自然生态环境保护获得较快发展,环境科技和环保产业初具规模,国际合作初见成效,环境管理体系初步建成。但是,浙江省人多地少资源贫乏,环境污染形势仍不容乐观,生态破坏现状仍比较严重。学习贯彻十五大精神,把浙江省的环境保护工作推向21世纪,任重而道远。1理清思路适应新形势江泽民总书记在十五大报告中正确地分析了我国国情,强调在现代化建设中必须实施可持续发展战略,坚持环境保护的基本国策,正确处理经济发展…  相似文献   

6.
精制油废水处理工艺研究   总被引:4,自引:0,他引:4  
精制油废水的浓度高,水质变化大,生物降解性好,经试验,采用物化处理除油及生物处理后出水可达排放标准,对该废水的生物处理工艺,可生物降解性,营养,硫酸盐的影响,活性污泥率等作了较为深入的探讨。  相似文献   

7.
关于砖瓦业发展与污染防治对策思考   总被引:1,自引:0,他引:1  
1.砖瓦业的发展状况及污染现状随着我国改革开放的不断深入,经济建设得到快速发展,城乡建设突飞猛进,伴随建筑业的兴起,城市基本建设和农村私人建房的不断增多,建筑材料需求量与日俱增,出现了砖瓦业盲目发展的势头,带来了许多迫切需要解决的环境问题。目前,砖瓦业多数分布于乡镇农村。以浙江省富阳市为例,全市现有红砖窑Zoo余只,村、个体办184只,占92%,其中轮窑3O只,占15%,小土窑(吊线窑)17O只,占85%。砖窑分布带有区域群布性,富阳、新登、三山、常安、高桥等5个镇,已建有红砖窑15O余只,占富阳市总窑数的75%左右…  相似文献   

8.
内蒙古自治区兴安盟农牧业高新技术研究所所长、国家科技进步特等奖获得者王善堂,依据作物秸秆形成生化反应的逆反应原理,用生物复合酶和载体协同作用,将秸秆大分子分解为小分子,直至降解为氨基酸和葡萄糖,从而被动物直接吸收。在该过程中,不仅纤维素、细胞壁、细胞间质分解为营养物,同时,细胞壁被破坏,细胞内营养释放,从而使秸秆饲料转化率大大提高。经分解后的秸秆饲料,不仅为牛羊等食草动物充分吸收,而且,为猪、鸡等食粮动物充分消化。这种只需加入酶催化活化分解剂,秸秆在常温下,经2h生化反应就能制成高营养的秸秆饲料,被专家高度评价,认为该技术具有突破性,  相似文献   

9.
稀土系列催化剂对焦化废水的催化湿式氧化   总被引:4,自引:0,他引:4  
以稀土元素Ce制得催化剂系列,在高温,高压条件下对焦化废水进行催化湿式氧化研究,考察载体,焙烧温度,活性组分的配比对催化剂的催化活性的影响,以及反应温度,氧气分压,反应时间和催化剂用量对氧化过程的影响,设计正交实验确定最佳的工艺参数:反应温度为240℃,氧气分压3.0MPa,催化剂用量30g/L,此时废水的COD法除率达到90%以上。  相似文献   

10.
射流曝气器研究进展   总被引:15,自引:1,他引:14  
射流曝气技术的应用与完善,有赖于射流曝气器的研制与发展,本文综述了射流曝气器的研究进展,并根据供气方式,工作压力,结构类型,安装方式,安装高度进行了分类,其中着重详述了对研发射流器比较重要的结构类型,最后指出射流曝气的研究趋势。  相似文献   

11.
The incentives and approaches for modelling chemical fate at a continental scale are discussed and reviewed. It is suggested that a multi-media model consisting of some 20-30 regions, each of which contains typically seven environmental compartments represents a reasonable compromise between the issues of the need for detailed resolution, avoidance of excessive data demands and inherent complexity and transparency. Strategies adopted in compiling the Berkley-Trent (BETR) model for North America are discussed and used to illustrate the issues of selecting appropriate number and nature of segments, treatment of air and water flows and the acquisition of environmental data. It is suggested that GIS software can play a valuable role in gathering and processing such data and in the display and interpretation of the results of the model assessment. The BETR model will be a useful tool for describing the nature of persistence and long-range transport of chemicals of concern in the North American environment.  相似文献   

12.
为了探索污泥堆肥中重金属在土壤一植物系统中的积累与转移特性,通过温室盆栽实验,分析了污泥堆肥对草坪草高羊茅、黑麦草和白三叶生物量积累的情况,研究了污泥堆肥中Zn和Cu在植物和土壤中的分布特征。结果表明,污泥堆肥施用可以有效促进3种草坪草的积累生物量,在0~6kg/m2的污泥堆肥施用量范围内,草坪草的生物量积累随着施用量的增加而提高。土壤中Zn和Cu的含量随污泥堆肥施加量的增加而增大,85%以上的Zn和Cu残留在土壤中。污泥堆肥中的Zn和Cu均可以被植物吸收,随着污泥堆肥施用量的增加,草坪草对Zn和Cu的吸收量增大,但当污泥堆肥施用量超过一定阈值时,草坪草吸收zn和cu不再增加,甚至减少;对于不同的草坪草,这一阈值有所不同。植物对zn和cu的吸收量只占土壤中zn和cu减少量的5%左右。根据生物富集系数(BCF)的计算结果推测,污泥堆肥的施用对土壤环境的影响大于对植物体内累积zn和Cu的影响。  相似文献   

13.
GOAL, SCOPE AND BACKGROUND: [corrected] Historically, landfills have been the simplest form of eliminating urban solid waste with the minimum cost. They have been the most usual method for discarding solid waste. However, landfills are considered authentic biochemical reactors that introduce large amounts of contaminants into the environment in the form of gas and leachates. The dynamics of generation and the movement of gas in landfills depend on the input and output parameters, as well as on the structure of the landfill and the kind of waste. The input parameters include water introduced through natural or artificial processes, the characteristics of the urban solid waste, and the input of atmospheric air. The main output parameters for these biochemical reactors include the gases and the leachates that are potentially pollutants for the environment. Control systems are designed and installed to minimize the impact on the environment. However, these systems are not perfect and a significant amount of landfill gas could be released to the atmosphere through the surface in a diffuse form, also known as Non-controlled emission. In this paper, the results of the Non-controlled biogenic gas emissions from the Lazareto landfill in Tenerife, Canary Islands, are presented. The purpose of this study was to evaluate the concentration of CH4 and CO2 in the soil gas of the landfill cover, the CH4 and CO2 efflux from the surface of the landfill and, finally, to compare these parameters with other similar landfills. In this way, a better understanding of the process that controls biogenic gas emissions in landfills is expected. METHODS: A Non-controlled biogenic gas emission survey of 281 sampling sites was carried out during February and March, 2002. The sampling sites were selected in order to obtain a well-distributed sampling grid. Surface landfill CO2 efflux measurements were carried out at each sampling site on the surface landfill together with soil gas collection and ground temperatures at a depth of 30-40 cm.The CH4 efflux was computed from CO2 efflux and from the ratio CH4/CO2 in the soil gas. Soil gas samples were collected at a depth of 30-40 cm using a metallic probe and 20 cc hypodermic syringes, and later stored in evacuated 10 cc vacutainers for laboratory analysis of bulk composition. The gas sample was introduced in a vacutainer filled with deionized water and displacing the water until the vacutainer was filled with the gas sample in order to avoid air contamination from entering. The surface landfill temperature of the landfill was measured at a depth of 40 cm using a digital thermometer type OMEGA 871A. Landfill gases, CO2 and CH4, were analyzed within 24 hours using a double channel VARIAN micro-GC QUAD CP-2002P, with a 10 meter PORAPLOT-Q column, a TCD detector, and He as a carrier gas. The analysis temperature was 40 degrees C and the injection time was 10 msec. Surface landfill CO2 efflux measurements were performed using a portable NDIR spectrophotometer Licor-800 according to the accumulation chamber method (Chiodini et al. 1996). The data treatment, aimed at drawing the flux map and computing the total gas output, was based on the application of stochastic simulation algorithms provided by the GSLIB program (Deutsch and Journel 1998). RESULTS: Diffuse CH4 and CO2 efflux values range from negligible values up to 7,148 and 30,573 g m(-2) d(-1), respectively. The spatial distribution of the concentration and efflux of CO2, CH4 and soil temperature, show three areas of maximum activity in the landfill, suggesting a non-uniform pattern of diffuse degassing. This correlation between high emissions and concentration of CO2, CH4 and soil temperatures suggests that the areas of higher microbial activity and exothermic reactions are releasing CO2 and CH4 to the atmosphere from the landfill. Taking into consideration the spatial distribution of the CO2 and CH4 efflux values as well as the extension of the landfill, the Non-controlled emission of CO2 and CH4 to the atmosphere by the Lazareto's landfill are of 167 +/- 13.3 and 16 +/- 2.5 t d(-1), respectively. DISCUSSION: The patterns of gas flow within the landfill seem to be affected by boundary materials at the sides. The basalt layers have a low permeability and the gas flow in these areas is extensive. In this area, where a basalt layer does not exist, the flow gas diffuses toward the sea and the flux emissions at the landfill surface are lower. This behavior reflects the possible dissolution of gases into water and the deflection of gases towards the surface at the basalt boundary. The proximity to the sea, the installation of a palm tree garden and, as a result, the contribution of water coming from the watering of this garden has reactivated the system. The introduction of sea water into the landfill and the type of boundary could be defining the superficial gas discharges. CONCLUSIONS: Results from this study indicate that the spatial distribution of Non-controlled emission of CO2 and CH4 at the Lazareto's landfill shows a non-uniform pattern of diffuse degassing. The northeast, central and northwest areas of the Lazareto's landfill are the three areas of high emissions and concentration of CO2 and CH4, and high temperatures. The correlation between high emissions and the concentration of CO2, CH4, and the high temperatures suggest that the areas of higher microbial activity and exothermic reactions are releasing more CO2 and CH4 to the atmosphere from the landfill. A high concentration of CO2 is probably due to the presence of methanotrophic bacteria in the soil atmosphere of the landfill. Patterns of gas flow within the landfill seem to be affected by boundary materials (basalt layers) of low permeability, and side boundaries of the flux emissions at the surface are higher. At the sides of seawater and sediment boundaries, flux emissions at the landfill surface are lower. This behavior reflects a possible dissolution of gases into the water and the deflection of gases towards the surface at the basalt boundary. With this study, we can compare the data obtained in this landfill with other landfills and observe the different levels of emission. The proximity to the sea and the installation of the palm tree garden palms and, as a result, the contribution of water coming from the watering of this garden has reactivated the system. Many landfills worldwide located in similar settings could experience similar gas production processes. RECOMMENDATIONS AND PERSPECTIVES: The need for investigating and monitoring sea water and sediment quality in these landfills is advisable. Concentrations and fluxes of contaminants and their impact in the area should be assessed. With this study we can compare the data obtained in these landfills with other landfills and observe the different levels of emission.  相似文献   

14.
Abstract

Norflurazon, oxadiazon, oxyfluorfen, trifluralin and simazine are herbicides widely used in the vineyards of the Barossa Valley, South Australia. The leaching behaviour of norflurazon, oxadiazon, oxyfluorfen and trifluralin was investigated on four key soils in the Barossa Valley. Leaching potential on packed soil columns and actual mobility using intact soil columns were investigated. On the packed soil columns, norflurazon was the most leachable herbicide. More of the herbicides were detected in the leachates from the sandy soils (Mountadam and Nuriootpa) than from the clayey soils (Lyndoch and Tanunda). Organic matter is generally low in soils in the Barossa region. Porosity and saturated conductivity significantly affect herbicide movement and in the sandy Mountadam and Nuriootpa soils, the water flux is greater than for the higher clay content Lyndoch and Tanunda soils. Increasing the time interval between herbicide application and the incidence of “rainfall”; reduced the amounts of herbicides found in the leachates. The use of intact soil columns and including simazine for comparison showed that both norflurazon and simazine were present in the leachates. Simazine was the first herbicide to appear in leachates. Sectioning of the intact soil columns after leaching clearly demonstrated that norflurazon and simazine reached the bottom of the soil columns for all soils studied. Greater amounts of norflurazon were retained in the soil columns compared with simazine. The other herbicides were mostly retained in the initial sections of the soil columns.  相似文献   

15.
- DOI: http:/dx.doi.org/10.1065/espr2005.06.262 Goal, Scope and Background The anthropogenic environmental emissions of chloroacetic acids and volatile organochlorines have been under scrutiny in recent years because the two compound groups are suspected to contribute to forest dieback and stratospheric ozone destruction, respectively. The two organochlorine groups are linked because the atmospheric photochemical oxidation of some volatile organochlorine compounds is one source of phytotoxic chloroacetic acids in the environment. Moreover, both groups are produced in higher amounts by natural chlorination of organic matter, e.g. by soil microorganisms, marine macroalgae and salt lake bacteria, and show similar metabolism pathways. Elucidating the origin and fate of these organohalogens is necessary to implement actions to counteract environmental problems caused by these compounds. Main Features While the anthropogenic sources of chloroacetic acids and volatile organochlorines are relatively well-known and within human control, knowledge of relevant natural processes is scarce and fragmented. This article reviews current knowledge on natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soils, with particular emphasis on processes in the rhizosphere, and discusses future studies necessary to understand the role of forest soils in the formation and degradation of these compounds. Results and Discussion Reviewing the present knowledge of the natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soil has revealed gaps in knowledge regarding the actual mechanisms behind these processes. In particular, there remains insufficient quantification of reliable budgets and rates of formation and degradation of chloroacetic acids and volatile organochlorines in forest soil (both biotic and abiotic processes) to evaluate the strength of forest ecosystems regarding the emission and uptake of chloroacetic acids and volatile organochlorines, both on a regional scale and on a global scale. Conclusion It is concluded that the overall role of forest soil as a source and/or sink for chloroacetic acids and volatile organochlorines is still unclear; the available laboratory and field data reveal only bits of the puzzle. Detailed knowledge of the natural degradation and formation processes in forest soil is important to evaluate the strength of forest ecosystems for the emission and uptake of chloroacetic acids and volatile organochlorines, both on a regional scale and on a global scale. Recommendation and Perspective As the natural formation and degradation processes of chloroacetic acids and volatile organochlorines in forest soil can be influenced by human activities, evaluation of the extent of this influence will help to identify what future actions are needed to reduce human influences and thus prevent further damage to the environment and to human health caused by these compounds.  相似文献   

16.
A natural experiment indicated that a link between the presence and concentration of four elements, copper, lead, nickel, and zinc in the influent to two wastewater reclamation plants to the presence and concentrations of the same four elements in the tap water of residential properties. There were 36 populations of results that were assessed for the normality of their distribution, the difference in their median concentrations, the similarity in the ratios of their median concentrations, and the correlations of the concentrations. The results of this study suggest that brass corrosion is the major source of these four elements in the water reclamation plants influent and that there are two distinct populations of brass sources, those in the early stages of dezincification where the release of the non-copper elements is dominant and those in the later stages where the release of copper dominates and the type of brass that is corroding.  相似文献   

17.
The occurrence of antihistamines in sewage waters and in recipient rivers   总被引:2,自引:1,他引:1  
Background, aim and scope  Each year, large quantities of pharmaceuticals are consumed worldwide for the treatment and prevention of human and animal diseases. Although the drugs and the metabolites observed in the wastewaters and in the environment are present at concentrations several orders of magnitude lower than the concentrations required to exert their effects in humans or animals, their long-term impact on the environment is commonly not known. In this study, the occurrence of six antihistamines, which are used for the relief of allergic reactions such as hay fever, was determined in sewage treatment plants wastewaters and in recipient river waters. Materials and methods  The occurrence of the antihistamines cetirizine, acrivastine, fexofenadine, loratadine, desloratadine and ebastine in sewage treatment plants wastewaters and in recipient river waters was studied. The analytical procedure consisted of solid-phase extraction of the water samples followed by liquid chromatography separation and detection by a triple-quadrupole mass spectrometer in the multiple reaction mode. Results  Cetirizine, acrivastine and fexofenadine were detected in both influent and effluent wastewater samples at concentration levels ranging from about 80 to 220 ng/L, while loratadine, desloratadine and ebastine could not be detected in any samples. During sewage treatment, the concentration of the antihistamines dropped by an average of 16–36%. Furthermore, elevated concentrations of antihistamines were observed in samples collected during the season of most intensive plant pollen production, i.e. in May. In the river water samples, the relative pattern of occurrence of cetirizine, acrivastine and fexofenadine was similar to that in the wastewater samples; although the concentration of the compounds was substantially lower (4–11 ng/L). The highest concentrations of the studied drugs were observed near the discharging point of the sewage treatment plant. Discussion  The highest concentrations of antihistamines in STP wastewaters correlate with the outbreak of allergic reaction caused by high amounts of plant pollens in the air. The analysis results of the river water samples show that the antihistamines are carried far away from the effluent discharge points. They may account for a part of the mix of pharmaceuticals and of pharmaceutical metabolites that occur downstream of STPs. Conclusions  Antihistamines are poorly degraded/eliminated under the biological treatment processes applied in the wastewater treatment plants and, consequently, they are continuously being discharged along with other drugs to the aquatic environment. Recommendations and perspectives  As a huge quantity and variety of drugs and their metabolites are continuously discharged to rivers and the sea, the compounds should be considered as contaminants that may possess risks to the aquatic ecosystem. Further studies are urgently needed on the environmental fate of the antihistamines and other pharmaceuticals in the aquatic environment. These studies should be concerned with the stability of the compounds, their transformation reactions and the identity of the transformation products, the distribution of drugs and their uptake and effects in organisms. On the basis of these studies, the possible environmental hazards of pharmaceuticals may be assessed.  相似文献   

18.
完全一体化结构的带式污泥浓缩压滤机   总被引:1,自引:0,他引:1  
通过对带式浓缩压滤机设计和以往的工程实践,从机械结构设计角度分析和对比了完全一体化带式浓缩压滤机与传统意义上的(搭接式)带式浓缩压滤机结构特点,并且提供了完全一体化带式浓缩压滤机的设计参数。  相似文献   

19.
Spliid NH  Helweg A  Heinrichson K 《Chemosphere》2006,65(11):2223-2232
Filling and cleaning of pesticide sprayers presents a potential risk of pollution of soil and water. Three different solutions for handling sprayers have been suggested: Filling and cleaning in the field, filling and cleaning on hard surfaces with collection of the waste water, and filling and cleaning on a biobed, which is an excavation lined with clay and filled with a mixture of chopped straw, sphagnum and soil with turf on top, and with increased sorption capacity and microbial activity for degradation of the pesticides. In the present study the degradation and leaching of 21 pesticides (5 g of each) was followed in an established full-scale model biobed. Percolate was collected and analysed for pesticide residues, and the biobed material was sampled at three different depths and analysed by liquid chromatography double mass spectrometry (LC-MSMS). During the total study period of 563 days, no traces of 10 out of 21 applied pesticides were detected in the percolate (detection limits between 0.02 and 0.9 μg l−1) and three pesticides were only detected once and at concentrations below 2 μg l−1. During the first 198 days before second application, 14% of the applied herbicide bentazone was detected in the leachate with maximum and mean concentrations of 445 and 172 μg l−1, respectively. About 2% of the initial mecoprop and fluazifop dose was detected in the percolate, with mean concentrations of 23 μg l−1, while MCPA and dimethoate had mean concentrations of 3.5 and 4.7 μg l−1, respectively. Leachate concentrations for the remaining pesticides were generally below the detection limit (0.02–0.9 μg l−1, below 1% of applied). Sorption studies of five pesticides showed that compounds with a low Kd value appeared in the leachate. After 169 days, all pesticides in the biobed profile were degraded to a level below 50% of the calculated initial dose. Pesticides with Koc values above 100 were primarily found in the uppermost 10 cm and degraded slowest due to the low bioavailability. The 11 most degradable pesticides were all degraded such that less than 3% remained in the biobed after 169 days.

Following second pesticide application of the biobed, leachate was sampled 215 and 365 days after the treatment. This showed the same pesticides to be leached out and at concentrations comparable to those of the first treatment. The same pesticides as after the first treatment were retained in the biobed.  相似文献   


20.
Wen K  Liang C  Wang L  Hu G  Zhou Q 《Chemosphere》2011,84(5):601-608
Rare earth elements (REEs) have been accumulated in the agricultural environment. Acid rain is a serious environmental issue. In the present work, the effects of lanthanum ion (La3+) and acid rain on the growth, photosynthesis and chloroplast ultrastructure in soybean seedlings were investigated using the gas exchange measurements system, chlorophyll fluorometer, transmission electron microscopy and some biochemical techniques. It was found that although the growth and photosynthesis of soybean seedlings treated with the low concentration of La3+ was improved, the growth and photosynthesis of soybean seedlings were obviously inhibited in the combined treatment with the low concentration of La3+ and acid rain. At the same time, the chloroplast ultrastructure in the cell of soybean seedlings was destroyed. Under the combined treatment with the high concentration of La3+ and acid rain, the chloroplast ultrastructure in the cell of soybean seedlings was seriously destroyed, and the growth and of photosynthesis were greatly decreased compared with those of the control, the single treatment with the high concentration of La3+ and the single treatment with acid rain, respectively. The degree of decrease and destruction on chloroplast ultrastructure depended on the increases in the concentration of La3+ and acid rain (H+). In conclusion, the combined pollution of La3+ and acid rain obviously destroyed the chloroplast ultrastructure of cell and aggravated the harmful effect of the single La3+ and acid rain on soybean seedlings. As a new combined pollutant, the harmful effect of REEs ions and acid rain on plant should be paid attention to.  相似文献   

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