Ascorbic acid reduction of residual active chlorine in potable water prior to halocarboxylate determination

In studies on the formation of disinfection byproducts (DBPs), it is necessary to scavenge residual active (oxidizing) chlorine in order to fix the chlorination byproducts (such as haloethanoates) at a point in time. Such research projects often have distinct needs from requirements for regulatory compliance monitoring. Thus, methods designed for compliance monitoring are not always directly applicable, but must be adapted. This research describes an adaptation of EPA Method 552 in which ascorbic acid treatment is shown to be a satisfactory means for reducing residual oxidizing chlorine, i.e., HOCl, ClO-, and Cl2, prior to determining concentrations of halocarboxylates. Ascorbic acid rapidly reduces oxidizing chlorine compounds, and it has the advantage of producing inorganic halides and dehydroascorbic acid as opposed to halogenated organic molecules as byproducts. In deionized water and a sample of chlorinated tap water, systematic biases relative to strict adherence to Method 552 were precise and could be corrected for using similarly treated standards and analyte-fortified (spiked) samples. This was demonstrated for the quantitation of chloroethanoate, bromoethanoate, 2,2-dichloropropanoate (dalapon), trichloroethanoate, bromochloroethanoate, and bromodichlorocthanoate when extracted, as the acids, into tert-butyl methyl ether (MTBE) and esterified with diazomethane prior to gas chromatography with electron capture detection (GC-ECD). Recoveries for chloroethanoate, bromoethanoate, dalapon, dichloroethanoate, trichloroethanoate, bromochloroethanoate, bromodichloroethanoate, dibromoethanoate, and 2-bromopropanoate at concentrations near the lower limit of detection were acceptable. Ascorbic acid reduction appears to be the best option presently available when there is a need to quench residual oxidants fast in a DBP formation study without generating other halospecies but must be implemented cautiously to ensure no untoward interactions in the matrix.     

Investigation of a ponding irrigation system to recycle agricultural wastewater

This article presents the results of natural carrying capacity of ponding irrigation system in Taoyuan agricultural zone, Taiwan. Both the systematic water quality and the ponding effects were examined. The ponding irrigation system included a flow channel and storage ponds. The data showed that most water characteristics deteriorated gradually from upper- to down-stream in the flow channel and the flow channel was not attributed to any self-purification in agricultural returning water practically. On the other hand, the results of storage ponds indicated that they can provide a natural treatment (i.e., the outlet water quality of the ponds is more desirable than that of the inlet). Consequently, the ponding irrigation system offers the natural self-purification in ponds to reuse and recycle the returning agricultural wastewater and to extend the irrigation capacity and efficiency.     

Morphophysiological Rearrangements in Fish in Response to Pollution (in the Light of S.S. Shvarts' Theory)

The results of a study on morphophysiological variation in fish inhabiting a subarctic lake exposed to chronic industrial pollution are described using an example of cisco, Coregonus lavaretus. It is shown that indices of the heart, liver, kidneys, gills, and fatness in these fish are increased significantly and have retained increased values for the past 20 years. The observed changes are analyzed on the basis of biochemical data. The results of studies on the dynamics of hematological parameters in fish are used for characterizing the development of toxicosis. Adaptive rearrangements associated with an increase in the metabolic rate and the activation of protective systems in the fish are explained in the context of S.S. Schvarts' concept. The idea is proposed that the additional energy cost of detoxification may be responsible for morphophysiological variation in fish under conditions of water pollution.     

Effect of Recycling on Material Properties of Glass-filled Polyethylene Terephthalate

Recycled plastics are considered low performance materials because their properties are expected to decrease drastically with recycling. The objective of this study was to characterize a 15 wt.% glass filled polyethylene terephthalate (rPET-15GF) using six recycle generations and four recycle ratios. Mechanical properties such as tensile strength, elastic modulus, and percent elongation to failure of the PET composite were determined for various recycle generations and recycle ratios. Results show that the mechanical properties of rPET-15GF decrease slightly per recycle generation. In contrast, thermal properties of rPET-15GF were not at all affected by the recycling process. This data demonstrates that recycled glass filled PET can be used effectively to fabricate components without significantly affecting their mechanical performance.     

Cost-effectiveness Analysis of Reducing the Emission of Nitrogen Oxides in Asia

The purpose of this study is to evaluate cost-effective reduction strategies for nitrogen oxides (NO _x ) in the Asian region. The source-receptor relationships of the Lagrangian “puff” model of long-range transportation, ATMOS-N, were used to calculate the wet/dry deposition of the nitrogen (N) in Asia. Critical loads of N deposition in Asia were calculated from the relationships between the critical load of sulfur (S) and balance of N in and out using the data of S critical load of RAINS-ASIA. The cost functions of N reduction of Asian countries were derived by the regression analysis with the data of cost functions of European countries used in RAINS. In order to assess the environmental impact, the gaps between N deposition and critical load of N were calculated. The emission of NO _x was reduced in some cases of this model, and the changes of gaps between N deposition and critical load were observed as well as the changes of the reduction cost. It is shown that a uniform reduction of NO _x emissions by countries in Asia is not cost-effective strategy.     

Pilot‐scale evaluation using bioaugmentation to enhance PCE dissolution at dover AFB national test site

An Interstate Technology and Regulatory Council (ITRC) forum was recently held that focused on six case studies in which bioremediation of dense nonaqueous‐phase liquids (DNAPLs) was performed; the objective was to demonstrate that there is credible evidence for bioremediation as a viable environmental remediation technology. The first two case studies from the forum have been previously published; this third case study involves a pilot‐scale demonstration that investigated the effects of biological activity on enhancing dissolution of an emplaced tetrachloroethene (PCE) DNAPL source. It used a controlled‐release test cell with PCE as the primary DNAPL in a porous media groundwater system. Both laboratory tests and a field‐scale pilot test demonstrated that bioaugmentation can stimulate complete dechlorination to a nontoxic end product and that the mass flux from a source zone increases when biological dehalorespiration activity is enhanced through nutrient (electron donor) addition and bioaugmentation. All project goals were met. Important achievements include demonstrating the ability to degrade a PCE DNAPL source to ethene and obtaining significant information on the impacts to the microbial populations and corresponding isotope enrichments during biodegradation of a source area. © 2007 Wiley Periodicals, Inc.     

Monitored natural attenuation forum: The case for abiotic MNA

The environmental fate and transport of chlorinated volatile organic compounds (VOCs) is controlled by the physical and chemical properties of the compound and the nature of the subsurface media through which the compound is migrating. Several processes (advection, dispersion, diffusion, biodegradation, and abiotic degradation, to name a few) result in a reduction in concentration and/or mass of contaminants in groundwater. Of these processes, biodegradation is often considered the dominant destructive attenuation mechanism for chlorinated VOCs. However, chlorinated VOCs can also degrade through abiotic processes and, in some cases, may be the primary or only destructive process occurring. © 2007 Wiley Periodicals, Inc.     

Emotional intelligence and individual performance: evidence of direct and moderated effects

We examined the direct and moderated effects of an ability‐based measure of emotional intelligence (MSCEIT© V2.0) on individual performance in a sample of business undergraduates. Controlling for general mental ability and personality, emotional intelligence explained unique incremental variance in performance ratings on only one of two measures of interpersonal effectiveness (public speaking effectiveness). However, the interaction of emotional intelligence with conscientiousness explained unique incremental variance both in public speaking and group behavior effectiveness, as well as academic performance (cumulative GPA). We conclude that the effects of emotional intelligence on performance are more indirect than direct in nature. Individuals must not only have emotional intelligence, but also must be motivated to use it. Copyright © 2006 John Wiley & Sons, Ltd.     

Water Network Synthesis Using Mutation-Enhanced Particle Swarm Optimization

Different techniques for the synthesis of industrial water reuse/recycle networks have been developed in recent process integration research. These tools range from graphical pinch analysis approaches to mathematical programming models. The latter have the advantage of being flexible enough to incorporate various water network constraints, but in many cases these are often non-linear, thus making the identification of global optima difficult. Recent work has demonstrated the effectiveness of metaheuristic algorithms such as particle swarm optimization (PSO), for finding good solutions these problems. This work describes the use of a modified PSO for solving mixed integer non-linear programming (MINLP) models for water network synthesis. By incorporating a mutation operator for the binary variables in the model, the algorithm is able to escape sub-optimal network topologies and proceed towards better solutions than can be found with ordinary PSO. Two case studies involving water recycle/reuse are used to demonstrate the new design methodology.