地下水—土壤原位生物修复技术研究进展

简要介绍地下水-土壤原位生物修复技术原理,分析了地下水-土壤原位修复技术影响因素,综述了国内外关于溶解氧的输送方法以及有机污染物在地下水-土壤中的迁移转化规律等方面的研究进展,指出了地下水-土壤原位生物修复技术的研究方向。     

近10年地下水中重金属与石油烃污染物修复研究进展

地下水作为人类生存与发展的重要资源也是农业国的发展基础,面对日益恶化的地下水污染问题已逐步引起国内外学者的广泛重视。因此,针对地下水中污染物从源头分析,并分类了污染物迁移及转化规律,并集中介绍了目前常见的地下水中污染物修复技术手段,期望为我国地下水重金属及石油烃类污染修复及治理提供参考。     

德国科研人员找到减少地下水硝酸盐污染新技术

正德国不莱梅大学的研究团队找到了一种解决地下水硝酸盐污染的新方法,利用多金属氧酸盐(POM)可有效降低地下水中过量的硝酸盐。参与这一项目研究的还有来自中国的研究人员,最新成果刊登在《欧洲无机化学杂志》上。地下水硝酸盐污染是德国一个长期已知的问题,根据德国政府2016年的地下水硝酸盐监测报告,德国有近1/3的地下水水质硝酸盐含量超标,这与过度使用农业化肥有关。类似的情况在许多国家也很严     

离子交换树脂脱除地下水中的硝酸盐

地下水是我国华北地区最重要的饮用水水源之一,特别是华北农村生活饮用水几乎全部来自地下水。然而,华北又是我国地下水硝酸盐污染比较严重的地区。研究开发适合华北农村分散式供水特点的地下水脱硝酸盐技术,对于保障农村的饮水安全具有十分重要的意义,为此把简单、高效且投资和运行费用相对较低的离子交换法用于脱除地下水中的硝酸盐。考察了普通强碱性阴离子交换树脂Purolite A 300E和硝酸盐选择性强碱性阴离子交换树脂Purolite A 520E脱除地下水中硝酸盐的效果,比较了地下水中SO42-和Cl-等阴离子对两类不同树脂交换性能的影响。结果表明,Purolite A 300E和Purolite A 520E树脂均能有效地去除地下水中的硝酸盐,两者的NO3--N饱和交换容量分别为49.02和48.54 mg/g。但是,当地下水中含有较高浓度的SO42-或Cl-时,Purolite A 520E脱除硝酸盐的效果明显优于Purolite A 300E。     

饮用水中硝酸盐的去除

作为重要的饮用水源,地下水中硝酸盐的污染日趋严重,硝酸盐对人体健康有严重的危害。物化方法(离子交换、电渗析、反渗透等)、生物反硝化、化学反硝化等工艺都可不同程度地去除作为饮用水的地下水中的硝酸盐,这些方法各有优缺点。本文综述了地下水中硝酸盐去除方法的应用和研究现状,并对其发展趋势做了简单的讨论。     

地下水硝酸盐生物处理技术探究

地下水作为水资源的重要组成部分,有着水量稳定、水质好的优点。正因如此,地下水一直是农业灌溉、工业和城市供水重要的来源之一。首先探讨了地下水硝酸盐污染的原因和危害性,并对地下水硝酸盐生物处理技术进行总结分析,为地下水硝酸盐生物处理技术的应用和发展提供资料参考。     

反硝化墙去除地下水硝酸盐研究进展

地下水硝酸盐污染越来越来越严重,过量摄入硝酸盐严重危害人类和家畜健康。反硝化墙是一种建造简单、无需管理维护的地下水硝酸盐原位修复技术。本文总结了反硝化墙对地下水中硝酸盐的去除效果、填充碳源种类、使用寿命及不利影响。     

煤炭地下气化对地下水的污染及其防控研究进展

煤炭地下气化（Underground Coal Gasification,UCG）是一种重要的煤炭资源转化技术,可提高煤炭资源的利用效率,但同时也带来地下水环境的污染风险。本文主要从UCG产生污染物对环境的影响及其修复防治角度着手,总结了UCG产生污染物的种类、转化迁移规律、净化修复方法和环境评估监测研究现状与进展,展望了未来UCG全面积极推广应加大其现场试验以及污染物监测研究力度的发展趋势,并为煤炭清洁利用领域的发展提供参考。     

地下水硝酸盐氮污染原位修复研究进展

可渗透反应墙(PRB)技术是一种经济、高效、节能的地下水污染原位修复方法。阐述了PRB去除地下水中硝酸盐的反应机理、墙体结构,分析比较了零价铁还原原位修复、零价铁还原/生物反硝化联合原位修复、自养反硝化修复地下水氮污染以及适合地下水硝酸盐去除的异养生物反硝化的碳源材料等研究进展,指出了各工艺的不足之处和研究方向,展望了PRB技术原位修复地下水氮污染的发展前景。     

微生物燃料电池原位修复地下水硝酸盐污染

通过构建双室微生物燃料电池(MFC),以阳极室有机底物作为电子供体,阴极室为模拟地下水含水层,以硝酸盐作为电子受体,进行MFC法原位修复地下水硝酸盐污染的模拟实验,研究连续流水力停留时间、阴极反硝化菌抑制以及盐桥数对硝酸盐去除率的影响。研究结果显示:MFC法可以有效的降解硝酸盐污染,降解率达60%~70%;阴极室可以忽略反硝化菌的自养反硝化作用;延长水力停留时间和增加盐桥数都有利于提高硝酸盐的降解率。     

Groundwater nitrate in Austria: a case study in Tullnerfeld

Contamination of groundwater from point and non-point sources is one of the major pollution problems. The agricultural community has become keenly aware of the impact of irrigation and fertilization on groundwater quality. In the plains of Austria groundwater is used as a major source of drinking water. In the last few decades nitrate concentrations in groundwater have increased dramatically. Among the various land uses, agriculture is reported to be the main source of groundwater contamination by nitrate. The study presented here was carried out at Tullnerfeld where nitrate levels in groundwater have been reported to be as high as 100 mg l^–1. To assess the contribution of various land uses to nitrate in groundwater, the Institute for Hydraulics and Rural Water-Management has installed facilities for measuring nitrate leaching and percolation under different cropping and management systems. The nitrate from fertilizers was measured using six lysimeters once a week. At the same time the nitrate levels in groundwater were simulated using the physically based model Environmental Policy Integrated Climate (EPIC). This paper gives a brief account of groundwater nitrate in Austria. The case study presented in this paper deals with the qualitative and quantitative aspects of groundwater nitrate by fertilizers and cover crops.     

Bio-electro-remediation: electrokinetic transport of nitrate in a flow-through system for enhanced toluene biodegradation

The availability of electron acceptors and nutrients is often limiting the microbiological clean-up of polluted groundwater at contaminated sites. In this study, the feasibility of electrokinetic processes to improve mass transfer was demonstrated in a model system simulating laminar groundwater flow conditions. Electrokinetic nitrate transport and enhanced biodegradation of toluene under denitrifying conditions was studied as function of voltage gradient in a new flow-through system. The study was done in a three-dimensional anaerobic model aquifer system filled with coarse sand. The influent area was divided into seven chambers thus enabling a separate addition of toluene and nitrate. Mesh electrodes were inserted laterally in order to form an electric field perpendicular to the flow direction with voltage gradients of 0, 0.125 and 0.25 V cm⁻¹, respectively. Biodegradation was studied after inoculation with a denitrifying microbial mixed culture. Application of the electric field resulted in nitrate migration into areas containing toluene. In the presence of denitrifying bacteria, the availability of nitrate in toluene polluted areas resulted in toluene biodegradation, demonstrated by nitrite formation and decreased toluene concentration.     

Nitrate in upper groundwater on farms under tillage as affected by fertilizer use,soil type and groundwater table

Indicators are needed to check whether policies on protection of groundwater are effective and if regulations are complied with. We evaluated various indicators at different scales, both in space and in time, and at different degrees of complexity. Groundwater was sampled on 34 arable farms for 3 years. Nitrate concentration in upper groundwater was low on clay soil. On sandy soil, peat layers reduced the nitrate concentration with about 80 mg/l on average. Sandy soils with high groundwater tables had nitrate concentrations that were less than half of those at sandy soils with low groundwater tables. The relationship between different fertilization variables and nitrate in groundwater was investigated for sandy soils without peat layers. N surplus poorly correlated with nitrate concentrations in groundwater when individual sampling points were studied, but clearly increased when data were averaged at the farm level. Soil mineral nitrogen correlated best with nitrate concentrations in groundwater. The relationships show that especially on well drained soil drastic measures will be inevitable to reach good water quality.     

Field nitrogen budgets and post-harvest soil nitrate as indicators of N leaching to groundwater in a Pacific Northwest dairy grass field

Dairy farms in the U.S. are expected to use farm-field nitrogen (N) budgeting techniques to determine appropriate agronomic manure application rates for crops. As part of nutrient management, post-harvest soil nitrate sampling is often relied upon to indicate the amount of N not used for crop growth during the growing season. A 4–1/2-year study was conducted that quantified the major N inputs, outputs, and residuals (soil and groundwater) at a commercial dairy field overlying a shallow unconfined aquifer in the Pacific Northwest. The purpose of the study was to evaluate the relationships between two indicators, (1) N mass residuals estimated by farm-field N budget and (2) post-harvest soil nitrate residuals, against measured groundwater nitrate-N concentrations following high seasonal recharge. A mass balance mixing-box spreadsheet model that accounts for the hydrogeologic characteristics of the site was used to quantitatively predict the impact of excess farm-field N on underlying shallow groundwater nitrate-N concentrations. Despite intensive sampling of N balance components and post-harvest soil nitrate conditions, the N-budget-predicted groundwater nitrate-N was 37% of the average field-measured early winter groundwater concentration. The post-harvest soil nitrate-predicted groundwater nitrate-N concentration was 140% of that measured in the field. Neither indicator provided a reliable prediction of the groundwater quality response to land application of nutrients using the spreadsheet model in this poorly drained/high water table setting. The mixing-box model provides a basic tool for testing hypothetical nutrient management scenarios in a variety of conditions. However, groundwater nitrate monitoring data are needed to determine actual outcomes.     

Denitrification in shallow groundwater in a coastal agricultural area in Japan

In a coastal agricultural area in the central part of Japan (Shizuoka), we found decreasing nitrate concentration with depth in a shallow groundwater, where the depth to water table varied between 0.6 and 1.2 m below ground surface. High nitrate concentrations (5–29 mg N L^–1) were often observed in the upper layer (0–2 m) of the groundwater, but the concentration decreased to less than 1 mg N L^–1 in the deeper layer. Ammonium was scarcely detected, and the concentration of dissolved oxygen was usually low (< 1 mgO₂ L^–1) in the groundwater. Nitrate in the groundwater often had very heavy nitrogen stable isotope ratios (>20{}). There was a negative relationship between nitrogen stable isotope ratio of nitrate and its concentration. When nitrate was injected into the groundwater with acetylene and bromide (a conservative tracer), nitrate concentration decreased to 20% of the initial level within 5 days, accompanied by the increase in nitrite and nitrous oxide concentration and a little change in bromide concentration. These results indicate that microbial denitrification plays a potential role in the decrease of nitrate in shallow groundwater at the study site.     

Experimental and mathematical modeling of water regime and nitrate dynamics on zero tension plate lysimeters in soil influenced by high groundwater table

Unlike laboratory experiments, which are mostly performed under controlled conditions, lysimeter experiments generally simulate actual field conditions. This paper focuses on an efficiency of the zero tension plate lysimeters, which were implanted in silty-clay soils influenced by a high groundwater table. Measurements and following numerical simulations using the HYDRUS-2D model were performed separately for each of 4 years (2007–2010) to assess water flow and nitrate fluxes (applied as NPK or UREA fertilizer). Low efficiency of lysimeters during the vegetation period was mostly caused by high plant water demand and possible water diversion to the sides when the groundwater table was low. The HYDRUS-2D model was able in some degree to reproduce observed water and nitrate outflows. The water outflow through the lysimeter occurred when the groundwater table was high and greater rainfall events occurred. Water and solute diverged from the plate towards the dryer surrounding soil when groundwater table was low. Pressure head, water velocity and nitrate concentration distributions simulated around the lysimeter plate illustrated that the lysimeter plate had a significant impact on the water regime and nitrate behavior within the soil profile. The lysimeter plate also acted as a barrier for water flow and solute transport also.     

The influence of nitrate reduction strategies on the temporal development of the nitrate pollution of soil and groundwater throughout Germany - a regionally differentiated case study

A GIS-based area-differentiating model has been used to analyze the nitrate pollution of soil and groundwater throughout Germany. The results of the calculations based on the model for the current situation show that a high potential for high nitrate pollution of the soil and groundwater (> 50 mg NO₃/l) is to be expected in all regions of Germany subject to intensive agricultural use. In order to achieve a sustainable use of water resources, effective strategies to reduce the nitrogen surpluses from agriculture must be developed and analyzed with respect to their spatial and temporal impact on the nitrate pollution of soil and groundwater, taking into consideration the various agricultural land usages as well as the different hydrological, hydrogeological and agricultural conditions.The effects of three different nitrate reduction strategies on the resulting N-surpluses and the nitrate concentration in the leachate were investigated: firstly, a stocking rate limitation, secondly, a limitation of both organic and mineral fertilizers and thirdly, a combination of three reduction measures consisting of a stocking rate limitation, an improvement of the nitrogen utilization factor by livestock and a higher utilization factor of nitrogen bound in organic fertilizers by crops. The analysis showed that separate application of each of these nitrogen reduction measures would only lower the nitrogen surpluses in a few regions. In order to achieve a considerable reduction of nitrate concentrations both in leachate from land under agricultural use and in the groundwater a combination of area-covering and regionally effective measures (scenario III) turned out to be most promising.     

反渗透法脱除地下水中硝酸盐的中试试验

采用Na2CO3/NaOH软化与反渗透组合工艺的一套日处理100 t硝酸盐和硬度严重超标的地下水中试与示范装置.半年多的试运行结果表明,中试与示范装置运行稳定,出水pH值、硬度和硝酸盐氮浓度全部符合《生活饮用水卫生标准》(GB5749-2006).中试与示范装置具有自动化程度高、运行管理简便的特点,适合于村镇小型供水单...