管道分质供水消毒副产物及其安全性评价

消毒副产物是饮用水中应主要控制的毒害物。然而，管道分质供水中消毒副产物特征及污染水平很少研究。以某一管道分质供水工程为例，对其中消毒副产物进行了详细研究。研究结果表明，管道分质供水消毒副产物在量与质上与其源水自来水存在很大差别。在管道分质供水中消毒副产物量少，一般不到自来水的1／10，且主要是一些毒性较低、与供水管材有关的溶出物。据此计算出管道分质供水由消毒副产物引起的致癌风险性一般不到其源水的1／10，其安全性大大提高。     

双柱双电子捕获检测器气相色谱法测定水中的苦味酸

以双柱双电子捕获检测器(ECD)气相色谱法分析水中苦味酸.结果表明:(1)双柱双ECD气相色谱法分析水中的苦味酸的最适反应温度为30℃,次氯酸钠加入量最适为2.0 mL;(2)利用不同极性的双柱双ECD气相色谱法分析水中的苦味酸具有良好的线性关系,精确度和准确度实验表明该方法可靠可行.     

Evaluating the dual porosity of landfilled municipal solid waste

Environmental Science and Pollution Research - The objective of this paper was to study the pore-size distribution of municipal solid waste (MSW) and provide a basis for understanding the mechanism...     

Inverse modeling of multicomponent reactive transport through single and dual porosity media

Compacted bentonite is foreseen as buffer material for high-level radioactive waste in deep geological repositories because it provides hydraulic isolation, chemical stability, and radionuclide sorption. A wide range of laboratory tests were performed within the framework of FEBEX (Full-scale Engineered Barrier EXperiment) project to characterize buffer properties and develop numerical models for FEBEX bentonite. Here we present inverse single and dual-continuum multicomponent reactive transport models of a long-term permeation test performed on a 2.5 cm long sample of FEBEX bentonite. Initial saline bentonite porewater was flushed with 5.5 pore volumes of fresh granitic water. Water flux and chemical composition of effluent waters were monitored during almost 4 years. The model accounts for solute advection and diffusion and geochemical reactions such as aqueous complexation, acid-base, cation exchange, protonation/deprotonation by surface complexation and dissolution/precipitation of calcite, chalcedony and gypsum. All of these processes are assumed at local equilibrium. Similar to previous studies of bentonite porewater chemistry on batch systems which attest the relevance of protonation/deprotonation on buffering pH, our results confirm that protonation/deprotonation is a key process in maintaining a stable pH under dynamic transport conditions. Breakthrough curves of reactive species are more sensitive to initial porewater concentration than to effective diffusion coefficient. Optimum estimates of initial porewater chemistry of saturated compacted FEBEX bentonite are obtained by solving the inverse problem of multicomponent reactive transport. While the single-continuum model reproduces the trends of measured data for most chemical species, it fails to match properly the long tails of most breakthrough curves. Such limitation is overcome by resorting to a dual-continuum reactive transport model.     

SBR新型运行方式下的反硝化脱氮除磷效能

为了提高低碳源污水脱氮除磷的效率,在传统SBR的基础上,通过改变SBR的运行方式和结构,构建了厌氧、好氧和缺氧在同一反应器中不同部位同时进行的反硝化除磷双泥系统。探究SBR工艺新的运行方式下的反硝化除磷脱氮效能,实验表明,在最佳运行工况下,即厌氧(进出水)30 min→上部好氧90 min(下部厌氧90 min)→缺氧50 min→沉淀10 min,系统对COD、氨氮、总氮和总磷的去除率分别达到94%、82.08%、76.78%和95.47%,出水能达到国家污水综合排放一级A标准(GB18918-2002)。     

Measuring in-cabin school bus tailpipe and crankcase PM2.5: a new dual tracer method

Exposures of occupants in school buses to on-road vehicle emissions, including emissions from the bus itself, can be substantially greater than those in outdoor settings. A dual tracer method was developed and applied to two school buses in Seattle in 2005 to quantify in-cabin fine particulate matter (PM2.5) concentrations attributable to the buses' diesel engine tailpipe (DPMtp) and crankcase vent (PMck) emissions. The new method avoids the problem of differentiating bus emissions from chemically identical emissions of other vehicles by using a fuel-based organometallic iridium tracer for engine exhaust and by adding deuterated hexatriacontane to engine oil. Source testing results showed consistent PM:tracer ratios for the primary tracer for each type of emissions. Comparisons of the PM:tracer ratios indicated that there was a small amount of unburned lubricating oil emitted from the tailpipe; however, virtually no diesel fuel combustion products were found in the crankcase emissions. For the limited testing conducted here, although PMck emission rates (averages of 0.028 and 0.099 g/km for the two buses) were lower than those from the tailpipe (0.18 and 0.14 g/km), in-cabin PMck concentrations averaging 6.8 microg/m3 were higher than DPMtp (0.91 microg/m3 average). In-cabin DPMtp and PMck concentrations were significantly higher with bus windows closed (1.4 and 12 microg/m3, respectively) as compared with open (0.44 and 1.3 microg/m3, respectively). For comparison, average closed- and open-window in-cabin total PM2.5 concentrations were 26 and 12 microg/m3, respectively. Despite the relatively short in-cabin sampling times, very high sensitivities were achieved, with detection limits of 0.002 microg/m3 for DPMtp and 0.05 microg/m3 for PMck.     

Extent of intracellular storage in single and dual substrate systems under pulse feeding

The study investigated the effect of acetate/starch mixture on the formation of storage biopolymers as compared with the storage mechanism in systems fed with these compounds as single substrates. Experiments involved two sequencing batch reactor sets operated at steady state, at sludge ages of 8 and 2 days, respectively. Each set included three different runs, one fed with acetate, the other with starch and the last one with the acetate/starch mixture. In single substrate systems with pulse feeding, starch was fully converted to glycogen, whereas 25 % of acetate was utilized for direct microbial growth at sludge age of 8 days, together with polyhydroxybutyric acid (PHB) storage. The lower sludge age slightly increased this fraction to 30 %. Feeding of acetate/starch mixture induced a significant increase in acetate utilization for direct microbial growth; acetate fraction converted to PHB dropped down to 58 and 50 % at sludge ages of 8 and 2 days respectively, while starch remained fully converted to glycogen for both operating conditions. Parallel microbiological analyses based on FISH methodology confirmed that the biomass acclimated to the substrate mixture sustained microbial fractions capable of performing both glycogen and PHB storage.     

Isolated Ficus trees deliver dual conservation and development benefits in a rural landscape

Many of the world’s rural populations are dependent on the local provision of economically and medicinally important plant resources. However, increasing land-use intensity is depleting these resources, reducing human welfare, and thereby constraining development. Here we investigate a low cost strategy to manage the availability of valuable plant resources, facilitated by the use of isolated Ficus trees as restoration nuclei. We surveyed the plants growing under 207 isolated trees in Assam, India, and categorized them according to their local human-uses. We found that Ficus trees were associated with double the density of important high-grade timber, firewood, human food, livestock fodder, and medicinal plants compared to non-Ficus trees. Management practices were also important in determining the density of valuable plants, with grazing pressure and land-use intensity significantly affecting densities in most categories. Community management practices that conserve isolated Ficus trees, and restrict livestock grazing and high-intensity land-use in their vicinity, can promote plant growth and the provision of important local resources.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-015-0645-9) contains supplementary material, which is available to authorized users.     

超滤/反渗透双膜技术深度处理印染废水

由于印染废水具有高盐度,可生化性差,使常规方法难于处理完全.采用超滤和反渗透双膜技术处理实际印染废水,考察了不同超滤膜对废水的预处理性能,研究了BW30和CPA2两种反渗透膜在不同操作条件下对印染废水的处理效果,并分析了相关膜通量下降的原因.结果表明,超滤能有效地去除废水浊度和大分子有机物,为反渗透提供良好的进水水质.两种反渗透膜的产水化学需氧量(COD)均小于10 mg/L,电导率小于80/μS/cm,其对有机物和盐的去除率分别可达99%和93%以上,显示该产水能回用于大部分印染工序.BW30膜产水水质稍好于CPA2,但通量低于CPA2.     

双室微生物燃料电池同时去除废水中的苯酚和硝酸盐

构建了一种双室微生物燃料电池,以苯酚为阳极燃料,同时去除阴极室的硝酸盐废水。结果表明,在闭合情况下,该微生物燃料电池阳极室的苯酚降解效率达到7.6 mg/(L·h),是开路情况下的2倍;反应开始后的5 d内,闭合系统阴极室硝酸盐降解效率达到4.43 mg/(L·d),是开路情况下的2倍多,表明了该MFC系统可以同时去除废水中2种难降解污染物,并且与传统的生物降解方式相比较,具有更快的降解速率。     

Wastewater treatment using bioreactor with dual functional ceramic membrane

A novel bioreactor including a group of dual functional ceramic membranes was developed and used for wastewater treatment. The ceramic membranes could be used for both aeration and filtration alternately, so fouling to ceramic membrane would be palliated effectively as its dual functions. For 100 days operation, COD removal ratio was 88∼97% for influent COD of 154∼1389 mg/L, and NH₄⁺-N removal ratio was 98% for influent NH₄⁺-N of 7.52∼51.35 mg/L. Some washing methods aiming at foul were discussed, experimental results indicated that surface foul is main factor to ceramic membrane and NaClO is better washing agent for the flux recover.     

Assessing chlorinated ethene degradation in a large scale contaminant plume by dual carbon-chlorine isotope analysis and quantitative PCR

The fate of chlorinated ethenes in a large contaminant plume originating from a tetrachloroethene (PCE) source in a sandy aquifer in Denmark was investigated using novel methods including compound-specific carbon and chlorine isotope analysis and quantitative real-time polymerase chain reaction (qPCR) methods targeting Dehaloccocoides sp. and vcrA genes. Redox conditions were characterized as well based on concentrations of dissolved redox sensitive compounds and sulfur isotopes in SO(4)(2-). In the first 400 m downgradient of the source, the plume was confined to the upper 20 m of the aquifer. Further downgradient it widened in vertical direction due to diverging groundwater flow reaching a depth of up to 50 m. As the plume dipped downward and moved away from the source, O(2) and NO(3)(-) decreased to below detection levels, while dissolved Fe(2+) and SO(4)(2-) increased above detectable concentrations, likely due to pyrite oxidation as confirmed by the depleted sulfur isotope signature of SO(4)(2-). In the same zone, PCE and trichloroethene (TCE) disappeared and cis-1,2-dichloroethene (cDCE) became the dominant chlorinated ethene. PCE and TCE were likely transformed by reductive dechlorination rather than abiotic reduction by pyrite as indicated by the formation of cDCE and stable carbon isotope data. TCE and cDCE showed carbon isotope trends typical for reductive dechlorination with an initial depletion of (13)C in the daughter products followed by an enrichment of (13)C as degradation proceeded. At 1000 m downgradient of the source, cDCE was the dominant chlorinated ethene and had reached the source δ(13)C value confirming that cDCE was not affected by abiotic or biotic degradation. Further downgradient (up to 1900 m), cDCE became enriched in (13)C by up to 8 ‰ demonstrating its further transformation while vinylchloride (VC) concentrations remained low (<1 μg/L) and ethene was not observed. The correlated shift of carbon and chlorine isotope ratios of cDCE by 8 and 3.9 ‰, respectively, the detection of Dehaloccocides sp genes, and strongly reducing conditions in this zone provide strong evidence for reductive dechlorination of cDCE. The significant enrichment of (13)C in VC indicates that VC was transformed further, although the mechanism could not be determined. The transformation of cDCE was the rate limiting step as no accumulation of VC occurred. In summary, the study demonstrates that carbon-chlorine isotope analysis and qPCR combined with traditional approaches can be used to gain detailed insight into the processes that control the fate of chlorinated ethenes in large scale plumes.     

Bacteria transport and deposition in an unsaturated aggregated porous medium with dual porosity

Environmental Science and Pollution Research - Bacterial transport and deposition play an important role in the assessment and prediction of subsurface pollution risks. Bacteria transport...     

Toluene vapor capture by activated carbon particles in a dual gas-solid cyclone system

Capturing of odorous compounds such as toluene vapor by a particulate-activated carbon adsorbent was investigated in a gas-solid cyclone, which is one type of mobile beds. The test cyclone was early modified with the post cyclone (PoC) and a spiral flow guide to the vortex finder. The proposed process may contribute to the reduction of gases and dust from industrial exhausts, especially when dealing with a low concentration of odorous elements and a large volume of dust flow. In this device, the toluene capturing efficiency at a 400 ppm concentration rose up to 77.4% when using activated carbon (AC) particles with a median size of 27.03 μm. A maximum 96% of AC particles could be collected for reuse depending on the size and flow rate. The AC regenerated via thermal treatment showed an adsorption potential up to 66.7% throughout repeated tests.

Implications: VOCs and particles have been of interest both in industrial field and public indoor spaces. In this study, a post cyclone (PoC) that utilizes a residual vortex from the mother cyclone was modified by inserting a flow guide and was applied to capture toluene vapor. The device of modified post-cyclone system can be used effectively in simultaneous treatment of gas-solid flow.     

Toluene vapor capture by activated carbon particles in a dual gas-solid cyclone system

Capturing of odorous compounds such as toluene vapor by a particulate-activated carbon adsorbent was investigated in a gas-solid cyclone, which is one type of mobile beds. The test cyclone was early modified with the post cyclone (PoC) and a spiral flow guide to the vortex finder. The proposed process may contribute to the reduction of gases and dust from industrial exhausts, especially when dealing with a low concentration of odorous elements and a large volume ofdust flow. In this device, the toluene capturing efficiency at a 400 ppm concentration rose up to 77.4% when using activated carbon (AC) particles with a median size of 27.03 microm. A maximum 96% of AC particles could be collected for reuse depending on the size and flow rate. The AC regenerated via thermal treatment showed an adsorption potential up to 66.7% throughout repeated tests.     

污泥的高温微好氧消化-厌氧消化工艺研究

城市污泥含有大量有机物和病原菌,需要稳定化处理。采用新型工艺高温微好氧与中温厌氧两级消化工艺(ATMD-MAD)处理城市污泥,与全程厌氧消化工艺(MAD)相比,不仅回收能源气体甲烷,而且缩短稳定化停留时间。55℃高温微好氧消化停留时间为2 d,后接35℃中温厌氧消化共运行24 d。结果表明,在ATMD-MAD系统中污泥的挥发性悬浮固体VSS去除率能在22 d时达到污泥稳定化要求的40%以上。ATMD-MAD工艺的单位VSS甲烷产量最高为496 m L/g VSS高于MAD工艺。在消化的前14天,可溶性挥发有机酸VFA在ATMD-MAD系统中的总量比MAD高出20%;在消化的第2天,ATMD-MAD系统中可溶性COD(SCOD)高出MAD工艺43.8%。ORP的变化反映了ATMD-MAD工艺保持了较好的厌氧状态,消化开始时的头2天限量曝气并没有给厌氧带来冲击。     

2×25 MW机组旋流板塔双碱法烟气脱硫除尘

2× 2 5MW发电机组烟气处理工程采用旋流板塔及双碱法工艺 ,取得了脱硫除尘一体化的效果 ,经济技术指标总体上优于国内外其他 FGD技术 ,是国内自行设计施工新建的最大烟气脱硫装置。经浙江省环境监测中心站监测 ,脱硫效率达到 89.4 % ,除尘效率达到 97.8% ,符合工程设计要求及我国相关环境标准。     

Semivolatile PAH and n-alkane gas/particle partitioning using the dual model: up-to-date coefficients and comparison with experimental data

The gas/particle partitioning coefficient K _p , of a semivolatile compound is a key parameter for its atmospheric fate. The most complete method of predicting K _p for polycyclic aromatic hydrocarbons (PAHs) is offered by the dual model, as it describes both the adsorption on soot and absorption into organic matter processes. However, experimental and model data exist almost exclusively for PAHs. In order to bridge this gap, experimental data on the phase partitioning of both PAHs and n-alkanes were collected at an urban and a remote site. Moreover, all the necessary parameters (e.g., octanol–air and soot–air partitioning coefficients) for the dual model have been collected and updated or (if missing) estimated for the first time. The results point out that both absorption and adsorption seem to contribute to the partitioning of PAHs and n-alkanes. However, it seems that the dual model always underestimates the particle sorption not only for PAHs but also for n-alkanes.     

Preparation and characterization of modified dual network dust suppression gel based on sodium alginate and soluble starch

Aiming at the problems of complex environment and serious dust pollution in large open-pit coal yards, a dust suppression gel with a dual network structure was prepared by modifying the soluble starch and sodium alginate with iron ions. The changes of functional groups, thermal stability, and morphology structure before and after the reaction were analyzed by FTIR, TG-DSC, and SEM, and the formation mechanism of the dual network was revealed by XPS. Furthermore, the water absorption and water retention experiments proved that the dual network structure is more conducive to water retention than the single-layer network. According to molecular dynamics simulations and contact angle experiments, gel and adsorbed water molecules can approach coal dust molecules on their own to contact, wet, and combine with coal dust. The adhesion test proved that the dust suppression gel with iron ions had better adhesion to dust. The anti-freezing test shows that the dust suppression gel has good anti-freezing performance. The antifreeze test shows that the dust suppression gel still has excellent freeze–thaw resistance at the test temperature of??-20℃. The mechanical property test shows that the dust suppressant gel can prevent the product from being damaged by external force. The acid and alkali resistance experiments showed that the acid and alkali resistance of the gel was improved under the condition of iron ion modification, and the flying of coal powder was effectively prevented. This research provides a new theoretical idea for coal dust control in complex environment.

     

双转盘反应器光催化处理罗丹明B

采用溶胶—凝胶法制备的TiO2/Ti电极为光阳极,Cu、Fe、Zn或C为阴极,组成双转盘反应器,以罗丹明B(RhB)为目标污染物,考察了反应条件对光催化效率的影响.结果表明,最佳反应条件:阴极材料为Cu;转盘转速为70 r/min;初始pH为2.5;Na2SO4质量浓度为1.0 g/L; RhB初始质量浓度为20 mg/L.在最佳反应条件下,处理RhB模拟废水30 min的脱色率可达到99.9％.双转盘反应器处理不同浓度的RhB时,其脱色率是单转盘的1.12～2.33倍,且倍数随着RhB浓度增大而增加,表明双转盘反应器可高效地光催化处理高浓度染料废水.