Effect of aeration on steady-state conditions in non- and partially aerated low-loaded biofilter

Excessive growth of biomass and retention of solids associated with air bubbles lead to bed clogging, which affects the biofilters?? performance. Two experiments were carried out in a submerged biofilter at the flow velocity of 0.5?m?h^?1, for an organic loading rate of 51?g C m^?3?h^?1 and a nitrogen loading rate of 13?g NH₄-N?m^?3?h^?1, one with the biofilter not aerated, the other with the biofilter partially aerated. The results showed that the higher head losses occurred in the upper section of the biofilter, where there was a greater biomass development and a higher removal of organic carbon, ammonia and solids, with the maximum allowed head loss being reached in 16 and 8?days. In any case, the steady-state conditions were achieved after 2?days and were interrupted on the tenth day of experiment E1 and on the fifth day of experiment E2. This allowed defining different operating cycles that enabled an average organic removal rate of 12.7?g C m^?3?h^?1 (27?%) and an average ammonia removal rate of 1.1?g NH4-N?m^?3?h^?1 (9?%) without aeration, and of 35.8?g C m^?3?h^?1 (76?%) and 6.3?g NH4-N?m^?3?h^?1 (51?%) with aeration. Regardless of the aeration conditions, more than 90?% of TOC and NH4-N removal occurred in the upper section. After the backwashing cycle, the biofilter returned to steady-state conditions in 6?h (without aeration) and 7?h (with aeration).     

液液萃取对邻苯二甲酸酯单体稳定碳同位素比值分馏的影响初探

邻苯二甲酸酯(PAEs)是地下水中主要的有机污染物,其单体的稳定碳同位素比值变化特征有望作为其溯源与过程示踪的依据,为更好地控制其对环境的污染提供可靠的信息.研究表明,在样品前处理过程中涉及一些物理变化过程,有机污染物的稳定碳同位素分馏效应不明显.本文应用液液萃取对样品进行前处理,气相色谱-同位素比值质谱联用法( GC - IRMS)测定地下水中5种邻苯二甲酸酯单体,包括邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二丁酯(DBP)、邻苯二甲酸二(2-乙基己基)酯(DEHP)、邻苯二甲酸二异丁酯(DIBP)的稳定碳同位素比值,探讨PAEs在液液萃取过程中5种单体稳定碳同位素比值分馏情况.分析结果表明,萃取前后PAEs的碳同位素比值没有显著的变化,说明液液萃取可以作为GC - IRMS测定邻苯二甲酸酯单体稳定碳同位素比值的前期预处理方法.     

Occurrence of phthalate esters around the major plastic industrial area in southern Taiwan

The increasing usage and disposal of plastic products could cause the wide distribution of phthalate esters (PAEs) in various environmental media. In this study, six PAE compounds, namely dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, benzyl butyl phthalate, di(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate, were analyzed in various samples collected from the major plastic industrial area of southern Taiwan, including soil, fertilizer and plastic products, for the purposes of identifying of the possible sources of PAEs and assessing the related health risk. The results show that PAEs in soil samples was dominated by DEHP, with the total concentrations in the range of 0.7?±?0.5, 0.2?±?0.1, and 0.3?±?0.2 mg kg^?1 for soil samples from farmland, household back gardens and the roadside, respectively. Contents of PAEs in chemical fertilizer (ND—0 0.87 mg kg^?1) were higher than that in organic fertilizer (ND—0.08 mg kg^?1), and PAEs concentrations (ND—316 mg kg^?1) in plastic mulching films were much less than those in the other types of plastic products (ND—1719 mg kg^?1), implying that major sources of PAEs in agricultural soil could be the use of chemical fertilizer and plastic products other than plastic mulching films. Health risk assessment suggested that, via the exposure to PAEs in soil, the potential non-cancer and carcinogenic risks for adults and children are minimal in most cases, except that a “moderate” carcinogenic risk for children exposure to DEHP. The results of this study can serve as a reference for further pollution prevention and environmental protection plans in relation to the industrial operation and discharge as well as the farming practices.     

Simulation of biofilter used for removal of air contaminants (ethanol)

Mathematic modeling and simulation of a biofilter system was developed for biofilters filled by three different packing materials such as granular activated carbon (GAC), compost mixed with diatomaceous earth (DE), and compost, respectively, and the effects of biofilter length, packing material, biological activity and the operation time of system on the removal of ethanol (influent contaminant) were studied. The mathematical model for analysis of mass transport phenomena in the biofilter was solved using a two-step, explicit finite difference approximation technique and computer simulation was carried out. The obtained results show that at the early stage of biofiltration the dominant mechanism is adsorption and after saturation of packing by contaminant, biological processes became the dominant mechanism. GAC packed biofilter needs more time to reach to steady state in comparison to the two other packing. GAC is the best adsorbent for contaminant removal; however, compost provides a better environment for microbial growth and activity. The proposed procedure is applicable to analyze the behavior of a biofiltration system used in removal of volatile organic compounds.     

Distribution of phthalate esters in the groundwater of Jianghan plain, Hubei, China

Samples of groundwater were collected from 17 sites in the Jianghan plain in July 2007. Sixteen phthalate esters (PAEs) were detected in samples collected by using solid-phase extraction (SPE)-gas chromatography (GC). The results show that there were one or several PAEs in all the samples, and the concentrations of total PAEs ranged from 80.12 to 1882.18 ng/L. Four PAEs, i.e. di-isobutyl phthalate (DIBP), di-n-butyl phthalate (DBP), bis (2-ethoxyethyl) phthalate (BEEP) and di (2-ethylhexyl) phthalate DEHP) were the dominant species. Among these, DIBP, DBP and DEHP concentrations were closely related to the water supply from the Yangtze River, Hanjiang River and Honghu Lake. However, the distribution of BEEP was irregular, which may be due to the application of some kind of products containing BEEP in the related areas. PAE distribution was irrelevant to the electrical conductivity and sample depth.     

西南典型地下河系统无机-有机指标特征及健康风险评价

岩溶地下水为全球约25%的人口提供饮用水源,地下河作为主要岩溶地下水类型,是中国西南岩溶区重要供水水源,掌握其水质污染状况及人体健康风险,对岩溶区水资源保护与安全用水具有重要意义。本文以广西桂林会仙狮子岩地下河系统为例,采集地下河水样品22组(无机和有机样品各11组),采用电感耦合等离子体质谱、离子色谱、气相色谱-质谱等方法测定11项无机离子、10项金属元素及41项有机指标的质量浓度,运用单指标污染标准指数法、健康风险评价模型揭示了研究区无机与有机指标分布、污染及健康风险。结果表明：(1)狮子岩地下河水中无机超标指标有NH~+₄(1.33倍)、Fe(1.2倍)、Al(1.5倍)和Mn(1.01倍),超标点多位于地下河排泄区;检出18项有机物,其中挥发性有机物(VOCs)、半挥发性有机物(SVOCs)和有机氯农药(OCPs)检出率分别为18.75%、30.77%和91.67%,研究区存在普遍的农药残留(49.14～109.83ng/L)。(2)与地下水对照值相比,研究区受到10项无机指标的轻度～中度污染、14项有机指标的轻度污染,个别采样点受到NO~-_3<...     

Assessment of organic pollutants (PAH and PCB) in surface water: sediments and shallow groundwater of Grombalia watershed in northeast of Tunisia

Toxic organic compounds in wastewater are serious threats for both human and environment healthy states. This study investigates the potential sources of surface water, sediment and groundwater pollution by polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyl (PCBs) as discharged by wastewater into the River of Oued El bey in northeastern Tunisia. Analysis indicates that the concentration of PAHs and PCBs are high in wastewater and vary from 0.37 to 0.83 mg/L and from 0.28 and 1.18 mg/L, respectively. The spatial distribution of PAHs and PCB in surface water showed a variation between 0.37 to 9.91 mg/L and between 0.1 to 0.47 mg/L, respectively. However, the quality of surface water is changed after wastewater evacuation at Oued Tahouna. The determination of PAH and PCB pollutants in groundwater shows a great interest in the development of water resources. The Concentration of these pollutants varying from 0.0204 to 1.93 mg/L and from 0.0052 to 0.196 mg/L, respectively. For PAH, analysis reveals also that naphtelene, fluorene, anthracene and chrysene are the most detected PAHs compounds in water and sediment samples while benzo[b]fluoranthene and benzo[a]pyrene are less present and in trace level. Higher concentrations of PAHs and PCBs are found in samples taken close to industrial areas of Bouargoub and Soliman, and wastewater discharge locations in Soliman. Analysis of the spatial distribution of PAHs and PCBs clearly link their higher concentration in water and sediments to wastewater and manufacturing discharges in the study area. In surface sediment, the organic pollutants are present. The cluster analysis for organic pollutants in different state and different matrix highlight a relationship between the wastewater evacuation and the water qualities which confirmed the direct response of the pollution sources on the surface water and groundwater organic pollution quality.     

Comparison of the biological NH3 removal characteristics of a three stage biofilter with a one stage biofilter

A three stage and a one-stage bench-scale biofilter with effective heights of 129 cm filled with same type of packing material were operated at different influent concentrations of ammonia in order to investigate their performance in treating waste gas streams. The columns contained a mixture of municipal compost inoculated with thickened municipal activated sludge as a base material and shredded hard plastic as a bulking agent in a 3:2 v/v ratio; the porosity, density and pH were 52 %, 0.65 and 7.2 respectively. Microbial acclimation to ammonia was achieved by exposing the three stage biofilter to an average inlet loading rate of 2.15g-NH₃/m³h and the one-stage to an average inlet loading rate of 1.32 g NH₃/m³h and an empty bed residence time of 60 s, for 10 days and 17 days respectively. Under steady-state condition, maximum elimination capacity (EC) was 9.85 g-NH₃/m³h at a loading rate of 9.86 g-NH₃/m³h for three-stage biofilter and 8.08 g NH₃/m³h at a loading rate of 8.13 g-NH₃/m³h for one-stage biofilter. The average pressure drop across biofilters bed was determined 33.76 Pa/m¹ in three-stage biofilter and 180.7 Pa/m¹ in one-stage biofilter. The three stage biofilter showed superior performance and gained more elimination capacity, shorter acclimation time, longer operation in steady-state condition and less pressure drop than one-stage biofilter.     

Degradation of 2, 4, 6-trinitotoluene in aqueous solution by ozonation and multi-stage ozonation biological treatment

The objective of this study was to explore the extent of 2,4,6-trinitrotoluene synthetic solution and red water mineralization by comparing conventional direct ozonation and multi-stage ozonation-biological treatment process. The alkaline hydrolysis was used for remediation 2, 4, 6-trinitrotoluene and red water at pH = 10.9. Nevertheless, the hydroxyl radicals would be generated by ozone decomposition with ozone dose of 0.177 g/L. The samples were subjected to chemical oxygen demand and total organic carbon analysis to monitor pollutants removal. The rate of 2, 4, 6-trinitrotoluene and red water pollutants degradation were quantified using high performance liquid chromatography. 2, 4, 6-trinitrotoluene synthetic solution resulted 55.5 % chemical oxygen demand removal by 3 h direct ozonation. Following direct ozonation the biological treatment twenty four hours chemical oxygen demand reached 98.9 % and 98.7 % removal using humic acid and river water 1 % ( v/v) inoculation singly and respectively. Conventional direct ozonation showed non significant change in total organic carbon degradation. While on using multi-stage ozone-biological treatment process where humic acid and/or river water were used as inoculums singly and respectively, total organic carbon fulfilled 73 % and 98.3 % removal. The process was one hour direct ozonation and followed by three days multi-stage ozone-biological treatment. In multi-stage ozone-biological treatment process, ozonation was effective to decompose total organic carbon and to produce biodegradable dissolved organic carbon easily removed by ozone oxidation up to 98.3 % in 2,4,6-trinitrotoluene synthetic solution. Pollutants removal achieved 99 % in authentic red water effluent using river inoculation 1 % (v/v) in 5 days. Nuclear Magnetic Resonance and Fourier Transformation Infra Red methods were performed to confirm types of pollutants content in red water.     

滹沱河平原地下水有机污染健康风险评价

本文根据有机物的挥发性对计算结果的影响大小,对U.S.EPA的健康风险评价模型进行适当改进,在模型中添加了污染物煮沸后的残留率TF项,评价分析了滹沱河冲积平原的健康风险。结果表明：（1）研究区典型的检出有机污染物为：三氯甲烷、四氯化碳、三氯乙烯和四氯乙烯,各采样点风险的主要贡献污染物为三氯甲烷和四氯化碳,主要的污染源应以工业和工业产品的使用污染为主;（2）对于非致癌风险和致癌风险,3种暴露途径的健康风险顺序均为：呼吸途径〉饮水途径〉皮肤接触途径;（3）非致癌风险中3个点均超过规定限值1.0,致癌风险中有4个点超过规定限值10~6;（4）使用和饮用开水并保持厂内工作车间和办公环境内空气畅通,可以在一定程度上降低健康风险。     

Treatment of an ECF bleaching effluent with white-rot fungi in an air-lift bioreactor

Pulp and paper mills utilise huge amount of natural resources, inorganic and organic materials along with large volume of water in different stages of paper manufacturing, resulting in a significant volume of effluents. The aim of this work was to investigate the treatment of a bleaching effluent [effluent chlorine free (ECF)] from the cellulose industry with white-rot fungi in an air-lift bioreactor. This effluent was submitted to the biological treatment with three white-rot fungi, and, every 24 h for 120 h, analytical tests were performed to analyse the quality parameters of treatment (COD, phenols, colour, pH). Before and after treatment, the effluent was analysed as its molecular mass distribution and absorptivity in the UV/VIS. Lentinus edodes, Trametes versicolor and Trametes villosa promoted similarly significant reductions in the following characteristics: (a) effluent colour (40–44 %), (b) total phenol (30–51 %) and (c) COD (37–43 %). The UV/visible spectrometry reading of the effluent after the fungi treatment showed a reduction in the absorbance of all wavelengths between 260 and 500 nm. The size exclusion HPLC profile of the effluent was modified, and the treatment promoted changes in the intensity of the peaks associated with compounds of high and low molecular weight. Phenoloxidases were produced during the treatment. T. versicolor produced the highest levels of laccase, and L. edodes was the only fungus that produced peroxidases.     

Off-line solid-phase extraction procedure for the determination of polycyclic aromatic hydrocarbons from aqueous matrices

An off-line solid-phase extraction procedure followed by high-performance liquid chromatography with ultraviolet detection for the determination of 16 priority polycyclic aromatic hydrocarbon pollutants in aqueous matrices was described. Diverse aspects determining extraction efficiency such as packing type (disk or cartridge), elution solvents and addition of organic modifiers to the sample were evaluated. Elution with acetonitrile yields the highest recoveries. Rinsing the sample bottle with acetonitrile and combining the rinse with the sample extract avoids the adsorption of polycyclic aromatic hydrocarbons on the walls of the water containers. The use of isopropanol or methanol 10 % (V/V) was the most appropriate amount for the enrichment of 2- to 6-ring aromatic compounds only on C18 cartridge. The recoveries for all studied polycyclic aromatic hydrocarbons are ranged from 71.4 to 95.2 % for a treated water samples of 500 mL. The proposed method gives very low detection limits (subnanograms per liter) and it has been applied to drinking water, surface water and industrial effluent (oil refinery) samples with good results.     

Research progress on aging of organic pollutants in geosorbents: a review

Geosorbents are the main host of anthropogenic organic pollutants and play a vital role in their fate and transport in the natural environment. Soil and sediment are the most common and abundant geosorbents in the natural environment; their interactions with organic pollutants, especially sorption and desorption processes, have been extensively studied from the perspectives of thermodynamics and kinetics. Recently, the aging of organic pollutants in geosorbents has drawn increased attention, leading to an improved understanding of interactions between organic pollutants and geosorbents and informing remediation criteria. Aging has been deemed important in accurately assessing ecologic and health risks of organic pollutants, and both positive and negative impacts have been reported in studies of natural and artificial sorbents. This paper summarizes recent research progress on organic pollutant aging in geosorbents, including related mechanism research, influence factors, bioavailability assessments, and biological and physicochemical remediation of aged organic pollutants. We also discuss issues in the current research and bring forward suggestions for future study.     

Case studies in organic contaminant hydrogeology

The effective management of domestic solid waste and hazardous, toxic, and radioactive waste is a major problem in the area of environmental geology and water sciences over the world. This series of case studies of organic contaminants from both solid and hazardous waste disposal facilities provides examples of these problems. The facilities were investigated to determine risks and liabilities before acquisition, to determine the site hydrogeologic conditions for design of appropriate groundwater monitoring plans, and/or to determine the potential for groundwater contamination. The results of these studies and investigations by Waste Management Inc. (WMI) and its consultants have shown certain relationships in the distribution of organic pollutants to the different geologic and hydrogeologic charac teristics of each facility. In each of the case studies, all 129 priority pollutants were analyzed in private wells and/or monitoring wells at the request of regulatory agencies. The 31 volatile organic compounds (VOCs) of the priority pollutant list were the majority of the organic compounds detected and these data are evaluated in each case study. The case studies are on disposal facilities located in glacial tills, carbonaceous weathered clay soils, weathered shale, limestone bedrock, dolomite bedrock, and alluvial and sedimentary deposits. A brief discussion of groundwater quality impacts and remedial measures also is included.Presented at the Second Annual Canadian/American Conference on Hydrogeology: Hazardous Wastes in Ground Water—A Soluble Dilemma. Banff, Alberta, Canada, June 26, 1985.     

Chlorinated volatile organic compounds found near the water surface of heavily polluted rivers

The objectives of this study were to identify the chlorinated volatile organic compounds near the water surface of two heavily polluted rivers in the south of Taiwan and compare their concentration distributions. Air samples were collected seasonally at the upstream, midstream and downstream water surfaces of each river and the chlorinated volatile organic compounds were analyzed qualitatively and quantitatively by gas chromatography and electron capture detector. Totally, twelve kinds of chlorinated volatile organic compounds were found at the water surfaces of both rivers and many of them were reported to be carcinogenic or probably carcinogenic to human. The results showed that each chlorinated volatile organic compound had its own distribution pattern and no good correlation of chlorinated volatile organic compounds between both rivers was obtained. The chlorinated volatile organic compounds identified at the river water surface of Fong Shan Stream showed much higher concentration than those of Chuen-Tsen River. Several chlorinated volatile organic compounds, including chlorodibromomethane, hexachlorobutadiene, 1,1,2,2-tetrachloroethene and 1,2-dibromo-3-chloropropane were found with much higher concentration (mean concentrations of 124.5 μg/m³, 334.5 μg/m³, 92.2 μg/m³, 268.4 μg/m³, respectively) at the water surface of Fong Shan Stream in some seasons (especially spring and summer, summer and winter, spring and winter, spring and summer, respectively) and they were reported to be possibly carcinogenic to human. Therefore, it may be concluded that the people living close to Fong Shan Stream possibly had higher health risks due to the release of volatile organic compounds from the heavily polluted river.     

气相色谱-质谱法快速测定罗氏海盘车中6种邻苯二甲酸酯类有机污染物

建立了气相色谱-质谱联用技术(GC-MS)测定罗氏海盘车中6种邻苯二甲酸酯类化合物(PAEs)的方法,采用丙酮-正己烷混合溶剂超声提取,通过中性氧化铝和弗罗里硅土填装层析柱净化样品,选用HP-5MS毛细色谱柱分离,选择离子监测模式(SIM)进行定性定量。该方法能同时分离测定罗氏海盘车中邻苯二甲酸二甲酯、邻苯二甲酸二乙酯、邻苯二甲酸二正丁酯、邻苯二甲酸丁基苄酯、邻苯二甲酸二(2-乙基己基)酯、邻苯二甲酸二正辛酯等6种邻苯二甲酸酯类化合物。在优化条件下,方法标准曲线的相关系数为0.9975～0.9996,回收率为80.30%～119.00%,精密度(RSD,n=7)为2.2%～5.7%,方法最低检出限为10.00 ng/g。运用建立的方法对罗氏海盘车样品进行分析,检测出罗氏海盘车中含有邻苯二甲酸二异丁酯、邻苯二甲酸二正丁酯、邻苯二甲酸二(2-乙基己基)酯3种污染物,3种污染物含量均低于欧盟的限量标准,同时远低于其他各类食品中的检出含量,样品中邻苯二甲酸二(2-乙基己基)酯平均含量偏高。本法具有高的选择性、灵敏度和准确度,适用于罗氏海盘车中痕量PAEs的测定,为保护海洋环境及海洋资源开发提供技术支持。     

Sediment-water column exchange of persistent organic pollutants (PAH<Subscript>s</Subscript> and PCB<Subscript>s</Subscript>) and their transport vector in El Bey watershed,Tunisia

El Bey river, which drains 60% of the pollutant load of several urban cities in the northeast of Tunisia, provides a good example of the transfer of organic and metallic pollutants that result from industrial and urban activity, and can be used to show how these charges are transported and discharged into the Gulf of Tunis. Persistent organic pollutants (PAH and PCB) in dissolved, particulate matter, bed sediments, and three wastewater effluents in El Bey watershed were analyzed. PAH (∑14PAHs) concentration ranged from 0.248 to 9.955 mg L^?1 and from 0.836 to 28.539 mg L^?1 in dissolved and particulate fraction respectively. The particulate/dissolved partition coefficient value (Kd) was less than one which confirmed the affinity of PAH to be adsorbed. In sediment, the high-molecular weight PAHs were found principally with percentage between 50 and 100% witch present 239.99 to 5362.19 μg kg^?1, which is relatively higher in comparison with other estuaries river. Contrary to PAH patterns, PCB were bound to dissolve fraction. Kd _(PCB) value (Kd?>?1) reflected this affinity which is related to environment energy. The spatial distribution and profile of analyzed organic pollutants confirmed the direct impact of wastewater effluent on the organic pollution level in three compartment of El Bey watershed and his profiles suggested different transport patterns.     

固相萃取-气相色谱／质谱法测定地面水中半挥发性有机物

利用XAD-2和XAD-8树脂吸附富集、有机溶剂洗脱、气相色谱／质谱法分析测定了福建九龙江流域水体中半挥发性有机化合物，共检出有机化合物138种，其中属于美国联邦环保总署和中国国家环保总局规定的优先控制有机污染物有20种。     

Impact of seaweeds on agricultural crop production as biofertilizer

Seaweeds or marine macroalgae are rich in diverse compounds like lipids, proteins, carbohydrates, phytohormones, amino acids, osmoprotectants, antimicrobial compounds and minerals. Their potential for agricultural applications is used since antiquity, but recent demands of organic farming and organic food stimulated much the application of organic treatments like seaweed extracts in agriculture. The benefits of seaweeds application in agricultural field are numerous and diverse such as stimulation of seed germination, enhancement of health and growth of plants namely shoot and root elongation, improved water and nutrient uptake, frost and saline resistance, biocontrol and resistance toward phytopathogenic organisms, remediation of pollutants of contaminated soil and fertilization. In this review, scientific progress in this field was collected and critically assessed to lay grounds for further investigations and applications.     

Solubilization of hydrocarbons by the dissolved organic matter in sea water

Water samples from Narragansett Bay and the Providence River, and fulvic acid/ saline water solutions were examined for their ability to solubilize n-alkane (n-C₁₆ and n-C₂₀), isoprenoid (pristane) and aromatic (phenanthrene and anthracene) hydrocarbons and dibutyl phthalate. Removal of the dissolved organic matter (D.O.M.) from the natural samples by activated charcoal and by ultra-violet oxidation resulted in a 50–99 per cent decrease in the amounts of n-alkanes and isoprenoid hydrocarbons solubilized. This decrease was directly related to the amount of D.O.M. removed. The solubilities of the aromatic hydrocarbons were unaffected by the D.O.M. Fulvic acid from a marine sediment, surface active organic material isolated at a chloroform/sea water interface, organic material extracted from a marine sediment by sea water, and organic matter contributed by a municipal sewage effluent, promote n-alkane solubility when added to NaCl solutions and re-enhance solubility when added to organic depleted sea water. The solubility of No. 2 fuel oil increased 2.5 times in the presence of fulvic acid (3.7 mg C/l.) with most of the increase seen in the alkane and isoprenoid components.N-Alkane solubility increases in fulvic acid/saline water solutions with increasing pH and reaches a maximum with respect to ionic strength at I = 0.3. There is evidence to suggest that the mode of solubilization of the hydrocarbons is by incorporation into micelles formed by intermolecular association of the surface active humic-type monomers. The presence of ionic species is a prerequisite for micelle formation.