Chemometric procedure for the study of fractionated wastewater ingredients using RP-HPLC/diode array spectrophotometer

A fast screening method of domestic wastewater is reported based on fractionation with RP-HPLC and diode array absorption detection implemented by chemometric treatment of the spectra using cluster analysis, deconvolution, simulation, and multiple regression statistical techniques. The proposed method is limited to constituents that absorb in the UV-Vis region which include most of the toxic organic pollutants.     

医院污水的电化学法消毒试验研究

应用电化学方法消毒处理医院污水,比较不同阳极材料消毒效果,并探讨消毒机理.试验表明,以涂有贵金属(钌、铂、铱)氧化物的钛板作阳极,不锈钢板作阴极,在电流密度6 mA/cm2、水力停留时间15 m in、空气流量为40 L/h、极水比为1.0的试验条件下,消毒后污水的总大肠菌群数<500CFU/L,达到国家一级排放标准(GB8978—1996).     

Evidence for Phytoremediation and Phytoexcretion of NTO from Industrial Wastewater by Vetiver Grass

The use of insensitive munitions such as 3-nitro-1,2,4-triazol-5-one (NTO) is rapidly increasing and is expected to replace conventional munitions in the near future. Various NTO treatment technologies are being developed for the treatment of wastewater from industrial munition facilities. This is the first study to explore the potential phytoremediation of industrial NTO-wastewater using vetiver grass (Chrysopogon zizanioides L.). Here, we present evidence that vetiver can effectively remove NTO from wastewater, and also translocated NTO from root to shoot. NTO was phytotoxic and resulted in a loss of plant biomass and chlorophyll. The metabolomic analysis showed significant differences between treated and control samples, with the upregulation of specific pathways such as glycerophosphate metabolism and amino acid metabolism, providing a glimpse into the stress alleviation strategy of vetiver. One of the mechanisms of NTO stress reduction was the excretion of solid crystals. Scanning electron microscopy (SEM), electrospray ionization mass spectrometry (ESI-MS), and Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the presence of NTO crystals in the plant exudates. Further characterization of the exudates is in progress to ascertain the purity of these crystals, and if vetiver could be used for phytomining NTO from industrial wastewater.     

Removal of anionic and cationic dyes from wastewater by adsorption using multiwall carbon nanotubes

This paper evaluated the efficiency and reusability of multiwall carbon nanotubes (MWNTs) on removal of cationic and anionic dyes under effect of pH, dose of MWNTs and concentration of dyes. The characterization of MWNTs is characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), Raman spectra and BET (Brunauer, Emmett and Teller) surface area. SEM and TEM analyses showed that MWNTs had size within nano scale range of 10–50 nm. The experimental results indicated that the efficiency of removal of MWNTs increase under condition of normal pH, at contact time 60 min with agitation speed 240 rpm and initial concentration of dyes 10 mg/l. Under these optimal conditions, the removal reached 98.7% and 97.2% for anionic dyes and cationic dyes, respectively. For economic use, MWNTs can be used more than one time where the same experiments with the already used MWNTs was repeated and it was found that the percent removal is almost the same.     

基于GM(1,1)模型的我国废水排放量及治理状况分析

根据近10年我国废水排放及治理现状,应用GM(1,1)模型预测出今后10年我国废水排放及治理状况并分析了废水排放量及治理费用增加的主因,为有关部门制定相关法规提供理论依据.     

The Effect of Synergism Behavior in Binary Mixtures of Some Surfactants with Ethyl Xanthat Absorbed on Clay for Wastewater Treatment

Surface tension, sedimentation, and turbidity experiments were conducted in order to study the synergism behavior of some surfactants with ethyl xanthat mixtures on the reduction of surface tension of their aqueous solutions and on the hydrophilicity of clay surface for using it as absorbent to oil in wastewater treatment. The following systems were studied: 1) potassium ethyl xanthat (KEX) with sodium cetyl sulphate (SCS); 2) potassium ethyl xanthat with cetyl trimethyl ammonium bromide (CTAB); and 3) potassium ethyl xanthat with ethoxylated palmetic acid (EPA). A synergistic effect of the combined reagents was found to enhance the hydrophilicity of clay and also to reduce the surface tension depending mainly on the surface properties of the mixtures.     

Analysis of long-chain fatty acids in grey wastewater with in-vial derivatisation

The presence and levels of long-chain fatty acids (C₆–C₂₀) in grey wastewater from bathrooms have been investigated. The acids were purified and concentrated by solid-phase extraction on strong anion exchange discs, in-vial derivatised to their corresponding methyl ester and subsequently analysed by GC-MS. The method was able to quantify the acids at concentration <1?µg/L with a recovery of 31–97%. The levels of fatty acids were found in the range of <0.5 to 27?100?µg/L and the highest levels were found for the saturated lauric (C₁₂), palmitic (C₁₆) and stearic (C₁₈) acids. The treatment efficiency of a local treatment plant was evaluated by comparing concentrations of fatty acids at the inlet and the outlet. It was found that the treatability decreases with increasing chain length for the saturated acids (19–100% degradation) whereas the corresponding mono unsaturated acids were more easily degraded.     

An inter-laboratory study of detection limits in the analysis of water and wastewater for organo-chlorine pesticides by liquid/liquid extraction and gas chromatography-electron capture detector (USEPA Method 608)

An inter-laboratory study was conducted to assess the Kaiser-Currie Model (KCM) for the determination of detection limits. Six laboratories participated in the analysis of samples prepared from distilled water, some containing organo-chlorine pesticides at a concentration of zero and other with a greater than zero concentration. The study consisted of three phases, the first of which was a study to assess the longer term variability of distilled water samples containing no organo-chlorine pesticides prepared by the participating laboratory analysed over a six month period. A second phase consisted of replicates of distilled water samples containing organo-chlorine pesticides prepared at a single concentration greater than zero by the laboratory and were analysed over several days. Finally, a third phase consisted of twelve distilled water samples, eleven containing organo-chlorine pesticides at a concentration of greater than zero and one with a concentration of zero prepared by a third party. Estimated detection limits were determined and then compared to the observed detection limits. Only in a minority of cases, where the distribution of results from samples containing a concentration of zero was normally distributed, did Currie's L _C accurately predict a concentration which corresponded to a 1% false positive rate in distilled water samples with a zero concentration of the study analyte. The USEPA's MDL performed more poorly. In the majority of cases, when any non-zero results were obtained from distilled water samples containing a concentration of zero, they were not normally distributed. Contrary to expectation, false negatives and false positives rarely occurred simultaneously on any given day. The variability between days of analysis and the use of noise reducing techniques proved to be a significant source of the observed non-normal distribution of distilled water samples. Conventional procedures based on the KCM and their underlying analytical and statistical assumptions did not provide useful predictions of laboratory sensitivity in most cases in this study.     

Determination of organic pollutants in coking wastewater by dispersive liquid–liquid microextraction/GC/MS

A method based on dispersive liquid–liquid microextraction coupled with GC/MS was developed for quantitative analysis of the major organic pollutants listed in the United States Environmental Protection Agency method 8270 and the 15 European‐priority polycyclic aromatic hydrocarbons in coking wastewater. The major parameters such as extraction solvent, dispersive solvent, solution pH, and extraction time were systematically optimized. The optimum extraction conditions were found to be: 15 μL mixture of 2:1 v/v carbon tetrachloride and chlorobenzene as the extraction solvent, 0.75 mL ACN as the dispersive solvent, solution pH of 8, and extraction time of 2 min. For the major pollutants listed in the United States Environmental Protection Agency 8270, the linear ranges were 0.1 to 100 mg/L, the enrichment factors ranged from 452 to 685, and the relative recoveries ranged from 67.5 to 103.5% with RSDs of 4.0–9.1% (n = 5) at the concentrations of 10 mg/L under the optimum extraction conditions. For the 15 polycyclic aromatic hydrocarbons, the linear ranges were 0.1 to 100 μg/L, the enrichment factors ranged from 645 to 723, and the relative recoveries ranged from 94.5 to 107.6% with RSDs of 4.6–9.0% (n = 5) at the concentrations of 10 μg/L. The usefulness of the developed method was demonstrated by applying it in the analysis of real‐world coking wastewater samples.     

湿式氧化用于染料废水脱色:过去20年回顾（英文）简

Wet air oxidation (WAO), a liquid phase reaction between organic materials in water and oxygen, is one of the most economical and technologically viable advanced oxidation processes for wastewater treatment, particularly toxic and high organic content wastewater. WAO is the liquid phase oxidation of organics or oxidizable inorganic components at elevated temperatures (125-320℃) and pressures (0.5-20 MPa) using gaseous oxygen (or air) as oxidant. In the past two decades, the WAO process was widely studied and applied in the treatment of dye wastewater. Compared to conventional WAO, catalytic WAO processes have higher efficiency and use moderate reaction conditions. The catalysts included homogenous and heterogeneous types. The key points that need to be solved are recycling of homogenous catalysts and better stability of heterogeneous catalysts. In the present review, the technological processes are first introduced, then some research history and hotspots of WAO research are presented, and finally, its application in the treatment of dye wastewater in the past two decades is summarized to reveal the impressive changes in modes, trends, and conditions used. The application includes model pollutant studies and wastewater tests.