A multi media load model for the Baltic Sea

The background of this work is the international decision process with regard to the selection of chemicals to be assessed with priority. In order to stress the precautionary principle, mass flows were analysed rather than concentrations, threshold values, etc., as preferred by the chemical legislation (which still excludes the marine area). Lindane, hexachlorobenzene (HCB), trichloroacetic acid and its sodium salt, medium-chained chlorinated paraffins and tributyltin (TBT) were selected due to their great relevance for the marine area. Trichloroacetic acid is an interesting model compound on account of its accidental formation by degradation of volatile chlorinated hydrocarbons and during chlorination processes. In addition, a hypothetical compound was modelled, representing a highly water-soluble substance with low vapour pressure. The balancing area is the Baltic Sea and its catchment area. In order to model the substance flows, the 'Input/Output-load model' has been developed. The model quantifies the shift and the distribution of a yearly load of the substance investigated from the terrestrial-limnic into the marine compartment (Baltic Sea). Water-soluble substances, which are usually considered to be of no concern, may enter the sea in great amounts and, if not degradable, remain there. It turned out to be necessary to take into account remobilisation, unintended formation and point as well as line-sources.     

Pollutant removal from municipal wastewater employing baffled subsurface flow and integrated surface flow-floating treatment wetlands

This article reports pollutant removal performances of baffled subsurface flow, and integrated surface flow-floating treatment wetland units, when arranged in series for the treatment of municipal wastewater in Bangladesh. The wetland units （of the hybrid system） included organic, inorganic media, and were planted with nineteen types of macrophytes. The wetland train was operated under hydraulic loading fluctuation and seasonal variation. The performance analyses （across the wetland units） illustrated simultaneous denitrification and organics removal rates in the first stage vertical flow wetland, due to organic carbon leaching from the employed organic media. Higher mean organics removal rates （656.0 g COD]（m2.day）） did not completely inhibit nitrification in the first stage vertical flow system; such pattern could be linked to effective utilization of the trapped oxygen, as the flow was directed throughout the media by the baffle walls. Second stage horizontal flow wetland showed enhanced biodegradable organics removal, which depleted organic carbon availability for denitrification. The final stage integrated wetland system allowed further nitrogen removal from wastewater, via nutrient uptake by plant roots （along with nitrification）, and generation of organic carbon （by the dead macrophytes） to support denitrification. The system achieved higher E. coli mortality through protozoa predation, E. coli oxidation, and destruction by UV radiation. In general, enhanced pollutant removal efflciencies as demonstrated by the structurally modified hybrid wetland system signify the necessity of such modification, when operated under adverse conditions such as： substantial input organics loading, hydraulic loading fluctuation, and seasonal variation.     

The impact of iodinated X-ray contrast agents on formation and toxicity of disinfection by-products in drinking water

The presence of iodinated X-ray contrast media (ICM) in source waters is of high concern to public health because of their potential to generate highly toxic disinfection by-products (DBPs). The objective of this study was to determine the impact of ICM in source waters and the type of disinfectant on the overall toxicity of DBP mixtures and to determine which ICM and reaction conditions give rise to toxic by-products. Source waters collected from Akron, OH were treated with five different ICMs, including iopamidol, iopromide, iohexol, diatrizoate and iomeprol, with or without chlorine or chloramine disinfection. The reaction product mixtures were concentrated with XAD resins and the mammalian cell cytotoxicity and genotoxicity of the reaction mixture concentrates was measured. Water containing iopamidol generated an enhanced level of mammalian cell cytotoxicity and genotoxicity after disinfection. While chlorine disinfection with iopamidol resulted in the highest cytotoxicity overall, the relative iopamidol-mediated increase in toxicity was greater when chloramine was used as the disinfectant compared with chlorine. Four other ICMs (iopromide, iohexol, diatrizoate, and iomeprol) expressed some cytotoxicity over the control without any disinfection, and induced higher cytotoxicity when chlorinated. Only iohexol enhanced genotoxicity compared to the chlorinated source water.     

毛细压力法对水处理滤料亲油亲水比的研究

基于Washburn方程,定义了滤料的亲油亲水比(LHR),利用毛细压力法测定了果壳、锰砂、陶粒、石英砂和瓷砂的润湿速率,计算了LHR值,并对滤料的表面微观结构进行了研究.实验表明,直线拟合程度较好,结果重现性较高.实验方法可行.数据可靠.其中果壳的LHR值最大,达到66.87,表现出了最强的亲油性,其次是锰砂、陶粒、石英砂,三者的亲油性略好于瓷砂,其LHR值分别为1.24、1.22、1.16和0.80,与XPS和FTIR分析结果一致,证实了滤料LHR值的差异主要取决于滤料表面微观结构的不同.     

DASB反应器处理生活污水的试验研究

DASB反应器作为新型现代厌氧反应器,具有结构简单、运行方便,处理效果好等优点,在处理生活污水方面有着广泛的应用前景。研究了常温条件下,DASB处理生活污水的启动运行,得出在最佳水力停留时间6h时,COD和SS的平均去除率分别达到81．48％和86．07％。     

Invertebrate community characteristics in biologically active carbon filter

Biologically active carbon (BAC) system was set up in a water plant of South China during January to December 2007,to study the invertebrate community characteristics of BAC filter.Thirty-seven invertebrate species were found,of which 28 belonging to rotifers.Filter operation could lead to an output of invertebrates in high abundances with the filtrate,and the maximum density could reach 5608 individuals/m 3.Average abundances in the effluent water increased in 27-33 folds in comparison to the influent water during the sampling period.Invertebrate community succession had the following trend:filter-feeding animals → small benthic invertebrates → large benthic and resistant invertebrates.Abundances of large-sized invertebrates (copepod adult and oligochaete) at bigger-media column were significantly higher than that at small-media column.The results implied the abundant species diversity of invertebrate in BAC filter.The relationship between invertebrate and biofilm still remain to be studied in detail.     

Stabilization of nanoscale zero-valent iron in water with mesoporous carbon (nZVI@MC)

Two challenges persist in the applications of nanoscale zero-valent iron(nZVI) for environmental remediation and waste treatment: limited mobility due to rapid aggregation and short lifespan in water due to quick oxidation. Herein, we report the nZVI incorporated into mesoporous carbon(MC) to enhance stability in aqueous solution and mobility in porous media. Meanwhile, the reactivity of nZVI is preserved thanks to high temperature treatment and confinement of carbon framework. Small-sized(～16 nm) nZVI nanoparticles are uniformly dispersed in the whole carbon frameworks. Importantly, the nanoparticles are partially trapped across the carbon walls with a portion exposed to the mesopore channels. This unique structure not only is conductive to hold the nZVI tightly to avoid aggregation during mobility but also provides accessible active sites for reactivity. This new type of nanomaterial contains ～10 wt% of iron. The nZVI@MC possesses a high surface area(～ 500 m~2/g) and uniform mesopores(～ 4.2 nm) for efficient pollutant diffusion and reactions. Also, high porosity of nZVI@MC contributes to the stability and mobility of nZVI. Laboratory column experiments further demonstrate that nZVI@MC suspension(～4 g Fe/L) can pass through sand columns much more efficiently than bare nZVI while the high reactivity of nZVI@MC is confirmed from reactions with Ni(II). It exhibits remarkably better performance in nickel(20 mg/L) extraction than mesoporous carbon, with 88.0% and 33.0%uptake in 5 min, respectively.     

Ducking for cover in the ‘blame game’: news framing of the findings of two reports into the 2010–11 Queensland floods

After a disaster, the media typically focus on who is to blame. However, relatively little is known about how the narrative of blame plays out in media coverage of the release of official disaster reports. This paper examines coverage by two Australian newspapers (The Courier‐Mail and The Australian) of the release of the Queensland Floods Commission of Inquiry's Interim Report and its Final Report to identify whether and how the news frame of blame was used. Given the absence of blame in the Final Report, the newspapers resorted to the frame of ‘failure’ in news and feature articles, while continuing to raise questions in editorials and opinion pieces about who was to blame. This study argues that situating coverage of the report within the news frame of failure and questioning who was to blame for the disaster limited the media's ability to facilitate a discussion about the prevention of similar disasters in the future.     

Transport of antibiotic resistance plasmids in porous media and the influence of surfactants

Transport of engineered antibiotic resistance plasmids in porous media has been reported to potentially cause significant spreading of antibiotic resistance in the environment. In this work, transport of an indigenous resistance plasmid pK5 in porous media was investigated through packed column experiments. At identical ionic strengths in CaCl₂ solutions, the breakthroughs of pK5 from soil columns were very close to those from quartz sand columns, indicating that transport of pK5 in quartz sand and soil was similar. A similarity in transport behavior was also found between pK5 and an engineered plasmid pBR322 that has approximately the same number of base pairs as pK5. The influence of surfactants, a major group of constituents in soil solutions, was examined using an engineered plasmid pcDNA3.1(+)/myc-His A. The impact of an anionic surfactant, sodium dodecyl sulfate (SDS), was negligible at concentrations up to 200 mg·L^–1. Cetyltrimethyl ammonium bromide (CTAB), a cationic surfactant, was found to significantly enhance plasmid adsorption at high concentrations. However, at environmentally relevant concentrations (<1 mg·L^–1), the effect of this surfactant was also minimal. The negligible impact of surfactants and the similarity between the transport of engineered and indigenous plasmids indicate that under environmentally relevant conditions, indigenous plasmids in soil also have the potential to transport over long distances and lead to the spreading of antibiotic resistance.

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Media coverage of the ‘UK flooding crisis’: a social panorama

A disaster referred to by the press as the ‘UK flooding crisis’ occurred between December 2015 and January 2016. This study employed three different levels of analysis to identify a multidimensional perspective adopted in the disaster reporting of the British Broadcasting Corporation (BBC). These levels revealed details about the social actors and their interactions. The set of news exposed diverse viewpoints on the crisis, from loss and damage to distinct affected subgroups to the various social engagement actions of aid and the multiplicity of technical response measures. The conclusions highlight considerable social amplitude in the BBC's coverage; however, owing to the reductionist approach of this media communicator, the field of action involving different social actors was not very clear in the content of the news, particularly with regard to cohesion, conflict/obstruction, and concernthe concept of crisis in its essence. In addition, the paper suggests new questions for future reports. 1