人工湿地数学模型模拟与应用

人工湿地生态系统具有投资低、出水水质好、抗冲击力强、增加绿地面积和操作简单等优点,在国外得到了较好应用.综述了人工湿地净化技术及湿地模型的研究进展,重点介绍了国外已经成功验证与应用的3种人工湿地模型的开发情况.同时应用某人工湿地的实测数据,通过对模型的验证和率定,表明模型在评估湿地功能和优化设计上的实用性.最后,对人工湿地模拟模型的应用前景及存在问题进行了评述.     

垃圾填埋场渗滤液的人工湿地处理

卫生填埋是垃圾处理的主要方式之一，填埋场产生的渗滤液对地下水和地表水会产生污染，因而需要进行有效的处理。介绍了垃圾渗滤液的人工湿地处理方法，包括人工湿地的组成、污染物去除机理、影响处理效率的因素等；对人工湿地处理渗滤液的工艺和国内外应用实例进行了总结；通过与传统处理方法相比，对其经济性进行了分析。可以看出．垃圾渗滤液的人工湿地处理法有成本低、构建和运行维护费用低、处理效果比较好等优点，在我国的某些地区有一定的适用性。     

人工湿地系统在我国污水处理中的应用

介绍了人工湿地系统在我国污水处理中的应用现状，认为设计方案、基质、水生植物的选用以及微生物降解等方面，是决定人工湿地系统净化效果的主要因素，最后指出了目前该法在全国各地推广的难度、存在的问题及解决这些问题的途径。     

反硝化碳源在人工湿地脱氮中的应用及其研究进展

碳源供给是制约人工湿地反硝化脱氮的重要因素,系统论述了反硝化碳源的类型及其在人工湿地反硝化过程中的作用,并对人工湿地中反硝化碳源的应用现状进行了讨论.反硝化菌与人工湿地脱氮有着密切关联,是人工湿地领域研究的焦点.此外,人工湿地中的环境条件、运行条件及湿地构建条件等都会对其反硝化效果产生重要影响,指出了通过改善上述条件提...     

垂直潜流人工湿地技术在上海市农村污水处理中的应用和发展

不同规模垂直潜流人工湿地技术在上海市农村污水处理实际应用的结果表明,采用垂直潜流人工湿地处理农村地区的污水在技术上、经济上和运行管理上都是可行的,值得在农村地区推广.同时,解决了垂直潜流人工湿地技术在上海市农村污水处理应用过程存在的诸多技术瓶颈问题,提出了多种防止垂直潜流人工湿地发生堵塞雍水的对策措施.     

污水处理中的人工湿地强化技术研究

人工湿地作为一种新型污水生态处理工艺受到越来越广泛的重视，在生活污水、特种工业废水、采矿污水、农业和畜牧业污水以及水产养殖废水等处理中得到了广泛的应用。但是其本身的局限却限制了它在高浓度废水、某些工业废水处理等方面的应用，在寒冷地区的应用也受到限制。本研究分析了一些强化技术（如湿地内部要素强化、工艺强化和工程强化等）在提高人工湿地的净化效能以及扩大其应用范围的可能性。     

人工湿地技术在景观水处理中的应用案例研究

介绍了人工湿地技术在景观水体处理中的工程应用具体实例.采用挺水植物、沉水植物和浮水植物组合配置的表面流人工湿地来净化直接排入景观水体的道路雨水;采用潜流人工湿地来处理易导致藻类暴发的支流河道循环水和补充水.连续4年的选择性跟踪监测证明,人工湿地技术在景观水体处理中具有良好的实际效果和应用推广价值.     

人工湿地在冬季低温地区的应用研究进展

人工湿地运行效果受季节、温度等因素影响较大,在冬季低温地区运行效率下降,特别是N、P污染物去除率偏低,限制了其在冬季低温地区的推广应用.结合目前国内外人工湿地在冬季低温地区的应用情况,分析了影响人工湿地低温运行的因素,并对提高人工湿地在冬季低温地区运行效率的各种强化措施进行了总结.     

人工湿地生态系统污水净化研究进展

人工湿地作为近 2 0年来发展起来的一种传统污水处理技术的一种廉价的替代方案 ,越来越受到世界各国的普遍重视。在分析中 ,详细介绍了人工湿地的概念、组成、基本的结构设计类型及其在污水净化中的应用领域和应用前景 ,同时详细论述了影响人工湿地污水净化效率的各种影响因素和制约条件及其各种影响因素之间的相互关系 ,并对今后研究的方向进行了展望 ,为人工湿地污水净化技术的应用研究提供了有益的参考。     

基于电阻率法的人工湿地堵塞区域探测方法

人工湿地污水处理技术已经得到广泛的应用,但目前对人工湿地堵塞问题,无法对堵塞区域进行精确定位.为了解决这个问题,根据潜流人工湿地结构和堵塞区域的特点,建立了长、宽、高分别为146、119和102 cm水槽物理实验模型,利用改进的高密度电阻率测井法开展了探测和定位人工湿地堵塞区域的实验研究,并结合人工湿地堵塞模型的Vis...     

Accumulation of metallic elements by Amanita muscaria from rural lowland and industrial upland regions

ABSTRACT

This study was carried out on the accumulation and occurrence of Ag, Al, Ba, Ca, Cd, Co, Cu, Fe, Hg, K, Mg, Mn, Na, Rb, Sr and Zn in the mushroom Amanita muscaria and forest topsoil from two lowland sites in the Tuchola Pinewoods in the north-central region and an upland site in the ?wietokrzyskie Mountains in the south-central region of Poland. Topsoil from the upland location showed Ag, Al, Ba, Ca, Cd, Co, Cu, Fe, Hg, Na and Zn at significantly higher concentration levels (pseudo-total fraction and often also the labile or extractable fraction) than at both lowland locations, where topsoil was richer in Mg, and similar in Rb. Amanita muscaria from the upland region differed from individuals collected in the lowland sites by higher concentration levels of Cd, Cu, Hg and Mn in caps. This could be related to higher concentration levels of the metallic elements in topsoil in the upland region. On other side, A. muscaria from the upland site was poorer in Co and Fe in caps, and in Ca, Co, Fe and Sr in stipes. In spite of the differences in content of the geogenic metallic elements in topsoil between the lowland and upland locations, A. muscaria from both regions was able to regulate uptake and accumulation of Ag, Al, Ba, Ca, K, Mg, Na, Rb and Zn, which were at similar concentration levels in caps but not necessarily in stipes.     

有机污染物湿地生物降解实验规律研究

本文以苯、甲苯和萘为对象 ,通过实验研究 ,测定有机污染物的土壤 水吸附平衡过程、在水溶液中生物降解过程以及在湿地系统 (即土壤 水 微生物系统 )中生物降解过程 ,并以质量守恒定律为基础 ,建立有机污染物湿地生物降解过程综合数学模型 ;数学模型通过实验验证。利用模型 ,定量预测了污染物生物降解所需的时间和程度 ,并提出动力学因子FK,判断污染物湿地生物降解速度的控制因素 ,定量预测了污染物在土壤固相的浓度分布规律     

Phytoavailability and extractability of potassium,magnesium and manganese in calcareous soil amended with olive oil wastewater

Abstract

Land disposal of olive oil wastewater using it as a soil amendment requires a knowledge of the effects that its application may produce on the status of the mineral nutrients in the plant‐soil system. A pot experiment using calcareous soil was performed in a growth chamber to examine the effects of olive oil wastewater on the availability and postharvest soil extractability of K, Mg and Mn. The experiment included 6 treatments: two rates of olive oil wastewater, two mineral fertilizer treatments containing K (which supplied K in amounts equivalent to the K supplied by the olive oil wastewater treatments), a K‐free mineral fertilizer treatment, and a control. The pots were sown with ryegrass as the test plant, harvesting 3 times at intervals of one month. Olive oil wastewater has demonstrated a considerable capacity for supplying K that can be assimilated by the plant, tending in fact to surpass the mineral potassium fertilizer tested. The application of olive oil wastewater tends to reduce the concentration of Mg in the plant, similarly to the effect of adding mineral potassium fertilizer. An enhancement of Mn availability takes place in the soil amended with olive oil wastewater, which on occasion has produced Mn concentrations in plant that could be considered phytotoxic or at least excessive. After harvesting, we observed an increase in the amount of exchangeable K in soil with added industrial wastewater. However, these increases are lower than those in soil treated with mineral potassium fertilizer. The levels of exchangeable, carbonate‐bound, organic‐bound and residual Mg in soil were higher in treatments incorporating olive oil wastewater than in those with added mineral K, with the opposite tendency occurring in the amount of Fe‐Mn oxides‐bound Mg in soil. Treatments based on olive oil wastewater, especially in high doses, increased the amount of exchangeable and carbonate‐bound Mn in soil, in comparison with treatments adding mineral fertilizers with or without K. In contrast, the addition of industrial wastewater caused a drop in the amount of Fe‐Mn oxides‐bound and organic‐bound Mn in soil.     

Long-term changes in nitrogen deposition in Finland (1990–2006) monitored using the moss Hylocomium splendens

Nitrogen deposition in Finland was investigated on the basis of the nitrogen concentration in the forest moss, Hylocomium splendens, collected during heavy metal moss surveys carried out in 1990, 1995, 2000, and 2005/06. Significant regional differences were found in the nitrogen concentrations in mosses. The concentrations were the highest in the southern part of the country in all the surveys, with a decreasing trend on moving northwards. The mean concentrations in the surveys were 1.07%, 1.00%, 0.89% and 0.92%. In general, the concentrations in mosses reflected nitrogen deposition at the level of the whole country. However, they did not correlate very well with the modelled nitrogen deposition because of the high local variation in the nitrogen concentration in H. splendens. One reason for the high variation was the effect of the structure of the tree stand on nitrogen concentrations in H. splendens.     

Transport and degradation of pesticides in a biopurification system under variable flux Part II: A macrocosm study

Transport of bentazone, isoproturon, linuron, metamitron and metalaxyl were studied under three different flows in macrocosms. The aim was to verify the observations from Part I of the accompanying paper, with an increase in column volume and decrease in chemical and hydraulic load. Very limited breakthrough occurred in the macrocosms for all pesticides, except bentazone, at all flows.From batch degradation experiments, it was observed that the lag time of metamitron and linuron decreased drastically in time for all flows, indicating a growth in the pesticide degrading population. This in contrast to isoproturon and metalaxyl, where an increase in lag time could be observed in time for all flows. From the batch degradation experiments, it could be concluded that the influence of flow on the lag time was minimal and that the inoculation of the pesticide-primed soil had a little surplus value on degradation.     

Heavy Metal Uptake by Two Edible Amaranthus Herbs Grown on Soils Contaminated with Lead,Mercury, Cadmium,and Nickel

The uptake of an element by a plant is primarily dependent on the plant species, its inherent controls, and the soil quality. Amaranthus hybridus (green herbs) and Amaranthus dubius (red herbs) were chosen to investigate their response and ability to accumulate and tolerate varying levels of elements in their roots and shoots. Red herbs and green herbs were grown in soil pots contaminated with three mixtures of Cd(II), Ni(II), Pb(II), and Hg(II). Plants in the control treatment were grown in the absence of the heavy metals mixture. The distribution of Cd, Ni, Pb, and Hg in the plants (in roots, stems, and leaves) was determined in two stages. Stage 1, after 5 weeks of plant growth and stage 2, full grown after 10 weeks of growth. In the red herbs the Cd concentration in the leaves at stage 2 was 150 ppm and was present in higher concentrations than Ni, Hg, and Pb. At the highest contamination level, in the green herbs plant, Hg was present in the highest concentration in the root, i.e., 336 ppm at stage 1, while the level in the leaves was 7.12 ppm. Both the green and red herbs species showed an affinity for Ni and Cd with moderate to high levels detected in the leaves, respectively.     

Trends in snowpack chemistry and comparison to National Atmospheric Deposition Program results for the Rocky Mountains, US, 1993–2004

Seasonal snowpack chemistry data from the Rocky Mountain region of the US was examined to identify long-term trends in concentration and chemical deposition in snow and in snow-water equivalent. For the period 1993–2004, comparisons of trends were made between 54 Rocky Mountain Snowpack sites and 16 National Atmospheric Deposition Program wetfall sites located nearby in the region. The region was divided into three subregions: Northern, Central, and Southern. A non-parametric correlation method known as the Regional Kendall Test was used. This technique collectively computed the slope, direction, and probability of trend for several sites at once in each of the Northern, Central, and Southern Rockies subregions. Seasonal Kendall tests were used to evaluate trends at individual sites.Significant trends occurred during the period in wetfall and snowpack concentrations and deposition, and in precipitation. For the comparison, trends in concentrations of ammonium, nitrate, and sulfate for the two networks were in fair agreement. In several cases, increases in ammonium and nitrate concentrations, and decreases in sulfate concentrations for both wetfall and snowpack were consistent in the three subregions. However, deposition patterns between wetfall and snowpack more often were opposite, particularly for ammonium and nitrate. Decreases in ammonium and nitrate deposition in wetfall in the central and southern rockies subregions mostly were moderately significant (p<0.11) in constrast to highly significant increases in snowpack (p<0.02). These opposite trends likely are explained by different rates of declining precipitation during the recent drought (1999–2004) and increasing concentration. Furthermore, dry deposition was an important factor in total deposition of nitrogen in the region. Sulfate deposition decreased with moderate to high significance in all three subregions in both wetfall and snowpack. Precipitation trends consistently were downward and significant for wetfall, snowpack, and snow-telemetry data for the central and southern rockies subregions (p<0.03), while no trends were noted for the Northern Rockies subregion.     

Fate of ah receptor agonists during biological treatment of an industrial sludge containing explosives and pharmaceutical residues

GOAL, SCOPE AND BACKGROUND: Sweden is meeting prohibition for deposition of organic waste from 2005. Since 1 million tons of sludge is produced every year in Sweden and the capacity for incineration does not fill the demands, other methods of sludge management have to be introduced to a higher degree. Two biological treatment alternatives are anaerobic digestion and composting. Different oxygen concentrations result in different microbial degradation pathways and, consequently, in a different quality of the digestion or composting residue, It is therefore necessary to study sludge treatment during different oxygen regimes in order to follow both degradation of compounds and change in toxicity. In this study, an industrial sludge containing explosives and pharmaceutical residues was treated with anaerobic digestion or composting, and the change in toxicity was studied. Nitroaromatic compounds, which are the main ingredients of both pharmaceutical and explosives, are well known to cause cytotoxicity and genotoxicity. However, little data are available concerning sludge with nitroaromatics and any associated dioxin-like activity. Therefore, we studied the sludge before and after the treatments in order to detect any changes in levels of Ah receptor (AhR) agonists using two bioassays for dioxin-like compounds. METHODS: An industrial sludge was treated with anaerobic digestion or composting in small reactors in a semi-continuous manner. The same volume as the feeding volume was taken out daily and stored at -20 degrees C. Sample preparation for the bioassays was done by extraction using organic solvents, followed by clean up with silica gel or sulphuric acid, yielding two fractions. The fractions were dissolved in DMSO and tested in the bioassays. The dioxin-like activity was measured using the DR-CALUX assay with transfected H4IIE rat hepatoma pGudluc cells and an EROD induction assay with RTL-W1 rainbow trout liver cells. RESULTS AND DISCUSSION: The bioassays showed that the sludge contained AhR agonists at levels of TCDD equivalents (TEQs) higher than other sludge types in Sweden. In addition, the TEQ values for the acid resistant fractions increased considerably after anaerobic digestion, resulting in an apparent formation of acid resistant TEQs in the anaerobic reactors. Similar results have been reported from studies of fermented household waste. There was a large difference in effects between the two bioassays, with higher TEQ levels in the RTL-W1 EROD assay than in the DR-CALUX assay. This is possibly due to a more rapid metabolism in rat hepatocytes than in trout hepatocytes or to differences in sensitivities for the AhR agonists in the sludge. It was also demonstrated by GC/FID analysis that the sludge contained high concentrations of nitroaromatics. It is suggested that nitroaromatic metabolites, such as aromatic amines and nitroanilines, are possible candidates for the observed bioassay effects. It was also found that the AhR agonists in the sludge samples were volatile. CONCLUSIONS: The sludge contained fairly high concentrations of volatile AhR agonists. The increase of acid resistant AhR agonist after anaerobic digestion warrants further investigations of the chemical and toxic properties of these compounds and of the mechanisms behind this observation. RECOMMENDATION AND OUTLOOK: This study has pointed out the benefits of using different types of mechanism-specific bioassays when evaluating the change in toxicity by sludge treatment, in which measurement of dioxin-like activity can be a valuable tool. In order to study the recalcitrant properties of the compounds in the sludge using the DR-CALUX assay, the exposure time can be varied between 6 and 24 hours. The properties of the acid-resistant AhR agonists formed in the anaerobic treatment have to be investigated in order to choose the most appropriate method for sludge management.     

Reduced downward mobility of metribuzin in fly ash-amended soils

Metribuzin, a triazine herbicide, is poorly sorbed in the soils, therefore leaches to lower soil profile. Fly ash amendment, which enhanced metribuzin sorption in soils, may play a significant role in reducing the downward mobility of herbicide. Therefore, the present study reports the effect of Inderprastha fly ash amendment on metribuzin leaching in three soil types. Fly ash was amended at 1, 2 and 5% levels in the upper 15 cm of 30 cm long packed soil columns. Results suggested a significant reduction in the leaching losses of metribuzin in fly ash-amended columns of all the three soil types and effect increased with increase in the level of fly ash. Even after percolating water equivalent to 362 mm rainfall no metribuzin was recovered in the leachate of 5% fly ash-amended columns. Fly ash application affected both metribuzin breakthrough time and its maximum concentration in the leachate. Further, it resulted in greater retention of metribuzin in the application zone and better effect was observed in the organic carbon poor soils.     

Sedimentation of PCDD/Fs and PCBs in the Gulf of Finland and the Gulf of Bothnia,the Baltic Sea

Sediment trap material was collected during May–December in the period 1996–2008 in three coastal areas and four open sea stations in the Finnish territory of the Baltic Sea. The highest sedimentation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) with a typical source-related congener profile from chlorophenol production dominated by highly chlorinated dibenzofurans was found close to a historical source in the Kymijoki estuary. This was an order of magnitude higher than in other river estuaries and two orders of magnitude higher than in the open sea stations. The sedimentation of polychlorinated biphenyls (PCBs) was also higher in river estuaries than in other areas. No significant decrease over a 12 year period of monitoring was found in concentration or in sedimentation in the Kymijoki estuary. In the western Gulf of Finland, the Archipelago Sea and the Gulf of Bothnia, the dominating congeners, calculated as toxic equivalent (TEQ) in sedimentation were 1, 2, 3, 7, 8-PeCDD and 2, 3, 4, 7, 8-PeCDF, often reported as the main congeners in deposition.