南京地铁隧道渗漏水治理方法

对南京地铁二号线矿山法区间渗漏水进行了分析,从防水设计与施工、渗漏水处理等方面进行了论述,提出了隧道渗漏水点处理的方法,进行了地下工程渗漏水处理的技术研究,达到了治理隧道渗漏的效果,解决了地下工程因防水等施工后仍然渗漏水的问题。     

餐饮业废水的处理

综述了餐饮业废水处理方法的现状,介绍了几种处理餐饮废水的工艺流程,并举一工程应用实例。     

Leachate flow rate behavior through geotextile and soil filters and possible remediation methods

This paper presents flow rate data in the form of system permeability values using various filtration schemes involving both geotextiles and natural soil filters. The tests were conducted over a 20-month period using six different types of leachate. In total, 96 different combinations were evaluated. In all cases, permeabilities decreased over time due to a combination of sediment clogging and/or biological clogging. When a steady state permeability value appeared to be reached, after approximately 6 months, the first of four remediation schemes were attempted. It was seen that water backflush is the most effective in reinstituting high flow rates, followed by backflushing with leachate and nitrogen gas. The least effective remediation scheme was vacuum extraction. Biocide treated geosynthetics were also evaluated, but results were inconclusive. This was due to the long times required and/or the remnants of the micro-organisms which could not pass through the various filtering systems.

The long-term minimum permeability values were not identified, nor were the design required permeabilities for the various landfills, in question. These important items are currently being investigated.     

Rhamnolipid biosurfactant mixtures for environmental remediation

This study investigated the efficiency of rhamnolipid biosurfactant and synthetic surfactant mixtures for improving the interfacial activity of the surfactant system against several light non-aqueous-phase liquids (LNAPLs). Since the rhamnolipid biosurfactant proved to be relatively hydrophilic, we hypothesized that mixtures of rhamnolipid biosurfactants with more hydrophobic synthetic surfactants would produce lower interfacial tensions (IFTs) than an individual rhamnolipid biosurfactant. The minimum IFT observed for rhamnolipid alone and toluene (0.03mN/m) was one order of magnitude lower than for hexane, decane, and hexadecane, demonstrating the relatively hydrophilic nature of the rhamnolipid. The low IFTs even at the low surfactant concentration used suggest mobilization as the dominant oil-removal mechanism versus supersolubilization. The critical micelle concentration (CMC) and critical microemulsion concentration (CmicroC) of the rhamnolipid were found to be 0.001w/w% (0.019mM) and 0.01w/w% (0.19mM), respectively. Three alkyl propoxylated (PO) sulfate synthetic surfactants were individually mixed with the rhamnolipid. As the hydrophobicity of the surfactant mixture approached that of the hydrocarbon, IFT values decreased by one to two orders of magnitude below that achieved with individual surfactants. This work shows that the rhamnolipid has excellent phase behavior at low concentrations and can be used in surfactant mixtures to achieve the low IFT values needed for environmental remediation, enhanced oil recovery (EOR), and other applications.     

Application of a membrane bioreactor for treating explosives process wastewater

A bench-scale anoxic membrane bioreactor (MBR) system, consisting of a bioreactor coupled to a ceramic cross-flow ultrafiltration module, was evaluated to treat a synthetic wastewater containing alkaline hydrolysis byproducts (hydrolysates) of RDX. The wastewater was formulated the same as hydrolysis wastewater and consisted of acetate, formate and formaldehyde as carbon sources and nitrite and nitrate electron acceptors. The MBR system removed 80-90% of the carbon sources, and approximately 90% of the stoichiometric amount of nitrate, 60% of nitrite. The reactor was also operated over a range of transmembrane pressure, temperature, suspended solids concentration, and organic loading rate to maximize treatment efficiency and permeate flux. Increasing the transmembrane pressure and temperature did not improve flux significantly. Increasing mixed liquor volatile suspended solids (MLVSS) concentration in the bioreactor decreased the permeate flux significantly. The maximum volumetric organic loading rate was 0.72 kg COD/m3/day. The maximum food-to-mass ratio was 0.50 kg N/kg MLVSS/day and 1.82 kg COD/kg MLVSS/day. Membrane permeate was clear and essentially free of bacteria, as indicated by heterotrophic plate count. Permeate flux ranged between 0.15 and 2.0 m3/m2 day and was maintained by routine backwashing every three days. Backwashing with tap water containing chlorine bleach every fourth or fifth backwashing was able to restore membrane flux to its original value.     

电动修复技术处理铬污染黏土试验研究

利用电动修复技术对红星化工厂铬渣污染黏土进行修复,试验电压分别为20,30,40,50,60V,以0.1mol/L KCl为两极电解液,阴极采用乙酸控制pH值在6左右,试验周期为5d.结果表明：电动修复能够去除土样中的铬,最高去除率可达58.26%;本试验50V即1.25V/cm电压梯度为经济有效的去除电压;Cr（Ⅵ）以含氧阴离子的形式向阳极迁移,Cr（Ⅲ）迁移较复杂,在沉淀态和游离态之间转换;阳极电解液中Cr（Ⅵ）的浓度易达到饱和,对Cr（Ⅵ）的去除产生抑制.     

Applicability of alkaline hydrolysis for remediation of TNT-contaminated water

This study was conducted to assess the applicability of alkaline hydrolysis as an alternative ex situ technology for remediating 2,4,6-trinitrotoluene (TNT)-contaminated water. TNT reactivity had a strong dependence on the reaction pH (11-12) and initial TNT (5-25 mg L(-1)) in batch systems, resulting in pseudo first-order transformation rate, k ranging between 1.9 x 10(-3) and 9.3 x 10(-5) min(-1). In continuous flow stirred-tank reactor (CFSTR) systems with initial TNT of 1 mg L(-1), the highest 74% of TNT reduction was achieved at the reaction pH of 11.9 and 2-day hydraulic retention time under steady-state condition. Oxalate was produced as the major hydrolysate in the CFSTRs, indicating a ring cleavage during alkaline hydrolysis. It was also believed that TNT alkaline hydrolysis occurred through the production of color-forming intermediates via dimerization. It is concluded that alkaline hydrolysis can be an alternative treatment technology for remediation of TNT-contaminated water.     

高速公路改扩建拓宽结合部处治方法

针对高速公路改扩建路基拓宽结合部的常见病害,深入分析其病害的成因——差异沉降,从填筑材料的固结本质、材料选取与施工工艺、拓宽结构设计方面探索了差异沉降机理,并提出了相应的处治方法,为公路改扩建工程提供了指导。     

An anaerobic two-layer permeable reactive biobarrier for the remediation of nitrate-contaminated groundwater

In this paper, an anaerobic two-layer permeable reactive biobarrier system consisting of an oxygen-capturing layer followed by a biodegradation layer was designed firstly for evaluating the remediation effectiveness of nitrate-contaminated groundwater. The first layer filling with granular oxygen-capturing materials is used to capture dissolved oxygen (DO) in groundwater in order to create an anaerobic condition for the microbial denitrification. Furthermore, it can also provide nutrition, such as carbon and phosphorus, for the normal metabolism of immobilized denitrifying bacteria filled in the second layer. The second layer using granular activated carbon as microbial carrier is able to biodegrade nitrate entering the barrier system. Batch experiments were conducted to identify the effect of DO on microbial denitrification, oxygen-capturing performance of zero valent iron (ZVI) powder and the characteristics of the prepared oxygen-capturing materials used to stimulate growth of denitrifying bacteria. A laboratory-scale experiment using two continuous upflow stainless-steel columns was then performed to evaluate the feasibility of this designed system. The first column was filled with granular oxygen-capturing materials prepared by ZVI powder, sodium citrate as well as other inorganic salts, etc. The second column was filled with activated carbon immobilizing denitrifying microbial consortium. Simulated nitrate-contaminated groundwater (40 mg NO₃–N/L, pH 7.0) with 6 mg/L of DO content was pumped into this system at a flow rate of 235 mL/d. Samples from the second column were analyzed for nitrate and its major degradation byproduct. Results showed that nitrate could be removed more than 94%, and its metabolic intermediate, nitrite, could also be biodegraded further in this passive system. Further study is necessary in order to evaluate performance of its field application.     

Internal separation distances for underground explosives storage in hard rock

Most recent studies on underground explosives storage have focused their attention on external safety distances, mostly inhabited distances for airblast, debris, and ground shock. Internal distances in prevailing codes generally deal with the need to prevent sympathetic detonation as a result of propagation by rock spall impact, or to prevent damage in an adjacent chamber in the event of an accidental explosion. For complex facilities, guidelines on separation requirements are often lacking. Also, there are several inconsistencies in the current separation requirements. This paper attempts to fill in the gap and rationalise the separation requirements for the various components of an underground storage facility. Recommendations will be made based on a comprehensive review of tunnel damage and results from large-scale tests.     

Detection and remediation of human-origin pollution at two public beaches in Virginia using multiple source tracking methods

Two public beaches (Anderson and Hilton) in Newport News, Virginia, were frequently closed to swimming in 2004 due to high Enterococcus spp. counts that exceeded the regulatory standard. The microbial source tracking (MST) methods of antibiotic resistance analysis (ARA) and fluorometry (to detect optical brighteners) were used in the summer of 2004 to determine the origins of fecal pollution at the two beaches. Both MST methods detected substantial human-origin pollution at the two beaches, in locations producing consistently high levels of Enterococcus spp. Investigations by municipal officials led to the fluorometric detection and subsequent repair of sewage infrastructure problems at both beaches. The success of the mitigation efforts was confirmed during the summer of 2005 using ARA and fluorometry, with the results cross-validated by pulsed-field gel electrophoresis (PFGE).     

A reactor model for pulsed pumping groundwater remediation

A hybrid in situ bioremediation/pulsed pumping strategy has been developed to cost effectively remediate a carbon tetrachloride plume in Schoolcraft, Michigan. The pulsed pumping system uses a line of alternating injection and extraction wells perpendicular to the direction of natural groundwater flow. The wells pump periodically to clean the recirculation zone between adjacent wells. During the pump-off phase, natural groundwater flow brings new contaminant into the recirculation zone. The wells are pumped again prior to breakthrough of contaminant from the recirculation zone. A computationally efficient reactor model has been developed, which conceptually divides the aquifer into injection, extraction, and recirculation zones, which are represented by a network of chemical reactors. Solute concentration histories from three-dimensional finite difference simulations and from field data confirm the reactor model predictions. The reactor model is used to investigate the optimal well configuration, pumping rate, and pumping schedule for achieving maximum pollutant degradation.     

关于防水结构混凝土工程出现渗漏的处理方法

分析了防水结构混凝土工程产生渗漏的原因,介绍了渗漏易产生的部位及检查方法,并提出了砂浆直接堵漏法、埋细绳堵漏法、铁皮堵漏法等裂缝渗漏水的处理方法,以保证建筑物的正常使用及其耐久性。     

Overview of lead remediation effectiveness

A Symposium on Lead Remediation Effectiveness, sponsored by the US Environmental Protection Agency, was held at Coeur d'Alene, Idaho, USA from 22-25 May, 2000. International participants from various levels of government, educational institutions, industry, and community representatives presented papers and posters on themes that ranged from engineering practices through community participation in the remediation processes. The papers in this volume represent a global distribution of sites, especially those outside the USA. In providing an overview of the symposium and the theme of Lead Remediation Effectiveness we have drawn on information from some presentations at the symposium, besides those described in this volume.     

Phosphate sources and their suitability for remediation of contaminated soils

Phosphate minerals and specifically apatite show promise for environmental cleanup because they can form stable compounds with a wide range of cationic contaminants. However, phosphate minerals naturally accumulate some heavy metals that may cause additional contamination of the environment if used improperly. Nine commercially available phosphate materials were evaluated for remediation of contaminated soil based on solubility, concentration of metal/metalloid impurities, and leachability of impurity metal/metalloids. The phosphate materials consisted of three groups: processed (i.e., fertilizers), mined (rock phosphates from different formations), and biogenic (ground fish bone). Processed and mined rock phosphates contained relatively high total concentrations of As, Co, Cr, and Cu but did not exceed the RCRA toxicity characteristic leaching procedure (TCLP) limits. Biogenic apatite contained much lower metal concentrations than processed and mined rock phosphate and was appreciably more soluble. By combining biogenic and mined phosphate it is possible to obtain a wide range of phosphate release rates, permitting rapid immobilization of contaminants while providing a slow release of phosphate for continued long-term treatment.     

Combination of surfactant solubilization with permanganate oxidation for DNAPL remediation

A combination of surfactant solubilization with permanganate oxidation of trichloroethylene (TCE) was studied in batch, flow-through column, and three-dimensional (3-D) tank tests. Batch results showed that chloride production, an indication of TCE degradation, followed a pseudo-first-order reaction kinetics with respect to KMnO4 in the presence of free-phase TCE. A higher chloride production rate was achieved when anionic surfactants were present. The observed pseudo-first-order reaction rate constant increased as the concentrations of anionic surfactants Ninate 411 and Calfax increased from 0% to 0.1%, 0.3%, and 1.0%. Column experiments on TCE reduction by permanganate in the presence and absence of surfactants were carried out using well-sorted coarse Ottawa sand. The peak effluent TCE concentration reached 1700 mg/L due to enhanced solubilization when both sodium dodecyl sulfate (SDS) and permanganate were used, in contrast to less than 300 mg/L when only permanganate solution was used. In addition, the effluent TCE concentration decreased much faster when SDS was present in the permanganate solution, compared with the case when SDS was absent. With an initial 1 mL of TCE emplaced in the columns, the effluent TCE concentration dropped to <5mg/L after 29-31h of flushing with 1% SDS and 0.1% KMnO4 solution in contrast to 37-73 h when only 0.1% KMnO4 was used. Furthermore, KMnO4 breakthrough occurred after 21-25 h of injection when SDS was present compared with 45-70 h later when SDS was absent. A slightly higher chloride concentration was observed in the earlier stage of the column experiment and the chloride concentration decreased quickly once KMnO4 was seen in the effluent. The 3-D tank test showed that the MnO2 precipitation front formed more quickly when 1% SDS was present, which further confirmed the observation from the column study.     

Magnetite and zero-valent iron nanoparticles for the remediation of uranium contaminated environmental water

The current work presents a comparative and site specific study for the application of zero-valent iron nanoparticles (nano-Fe⁰) and magnetite nanoparticles (nano-Fe₃O₄) for the removal of U from carbonate-rich environmental water taken from the Li?ava valley, Banat, Romania.Nanoparticles were introduced to the Li?ava water under surface and deep aquifer oxygen conditions, with a U^VI-only solution studied as a simple system comparator. Thebatch systems were analysed over an 84 day reaction period, during which the liquid and nanoparticulate solids were periodically sampled to determine chemical evolution of the solutions and particulates.Results indicated that U was removed by all nano-Fe⁰ systems to <10 μg L⁻¹ (>98% removal) within 2 h of reaction, below EPA and WHO specified drinking water regulations. Similar U concentrations were maintained until approximately 48 h. X-ray photoelectron spectroscopy analysis of the nanoparticulate solids confirmed partial chemical reduction of U^VI to U^IV concurrent with Fe oxidation. In contrast, nano-Fe₃O₄ failed to achieve >20% U removal from the Li?ava water. Whilst the outer surface of both the nano-Fe⁰ and nano-Fe₃O₄ was initially near-stoichiometric magnetite, the greater performance exhibited by nano-Fe⁰ is attributed to the presence of a Fe⁰ core for enhanced aqueous reactivity, sufficient to achieve near-total removal of aqueous U despite any competing reactions within the carbonate-rich Li?ava water.Over extended reaction periods (>1 week) the chemically simple U^VI-only solution treated using nano-Fe⁰ exhibited near-complete and maintained U removal. In contrast, appreciable U re-release was recorded for the Li?ava water solutions treated using nano-Fe⁰. This behaviour is attributed to the high stability of U in the presence of ligands (predominantly carbonate) within the Li?ava water, inducing preferential re-release to the aqueous phase during nano-Fe⁰ corrosion.The current study therefore provides clear evidence for the removal and immobilisation of U from environmental waters using Fe-based nanoparticles. As a contrast to previous experimental studies reporting impressive figures for U removal and retention from simple aqueous systems, the present work demonstrates both nanomaterials as ineffective on timescales >1 week. Consequently further research is required to develop nanomaterials that exhibit greater reactivity and extended retention of inorganic contaminants in chemically complex environmental waters.     

地下水曝气修复技术模型试验研究

地下水曝气法是一项有效的土壤和地下水修复技术。本文采用不同粒径的高强度喷丸玻璃珠模拟自然砂土,通过常规和离心模型试验得到以下几方面结论:气体在试样中的运动方式取决于试样粒径级配的大小;曝气影响区域的形状基本为锥面形,其大小主要受粒径级配、曝气压力、离心加速度等因素影响,试样粒径、离心加速度越大,曝气压力越小,则曝气影响区域越尖锐;气体流量受曝气压力和离心加速度等因素影响,同时气体质量流量与有效曝气压力的关系曲线斜率和渗气夹角与有效曝气压力的关系曲线斜率存在突变有效曝气压力一致现象;线曝气二维模型试验较点曝气模型试验,渗气夹角更大,横向扩展更宽。