Effluents from MBT plants: Plasma techniques for the treatment of VOCs

Mechanical–biological treatments (MBTs) of urban waste are growing in popularity in many European countries. Recent studies pointed out that their contribution in terms of volatile organic compounds (VOCs) and other air pollutants is not negligible. Compared to classical removal technologies, non-thermal plasmas (NTP) showed better performances and low energy consumption when applied to treat lowly concentrated streams. Therefore, to study the feasibility of the application of NTP to MBTs, a Dielectric Barrier Discharge reactor was applied to treat a mixture of air and methyl ethyl ketone (MEK), to simulate emissions from MBTs. The removal efficiency of MEK was linearly dependent upon time, power and specific input energy. Only 2–4% of MEK was converted to carbon dioxide (CO₂), the remaining carbon being involved in the formation of byproducts (methyl nitrate and 2,3-butanedione, especially). For future development of pilot-scale reactors, acting on residence time, power, convective flow and catalysts will help finding a compromise between energy consumption, desired abatement and selectivity to CO₂.     

The Regionalization of National‐Scale SPARROW Models for Stream Nutrients1

Schwarz, Gregory E., Richard B. Alexander, Richard A. Smith, and Stephen D. Preston, 2011. The Regionalization of National‐Scale SPARROW Models for Stream Nutrients. Journal of the American Water Resources Association (JAWRA) 47(5):1151‐1172. DOI: 10.1111/j.1752‐1688.2011.00581.x Abstract: This analysis modifies the parsimonious specification of recently published total nitrogen (TN) and total phosphorus (TP) national‐scale SPAtially Referenced Regressions On Watershed attributes models to allow each model coefficient to vary geographically among three major river basins of the conterminous United States. Regionalization of the national models reduces the standard errors in the prediction of TN and TP loads, expressed as a percentage of the predicted load, by about 6 and 7%. We develop and apply a method for combining national‐scale and regional‐scale information to estimate a hybrid model that imposes cross‐region constraints that limit regional variation in model coefficients, effectively reducing the number of free model parameters as compared to a collection of independent regional models. The hybrid TN and TP regional models have improved model fit relative to the respective national models, reducing the standard error in the prediction of loads, expressed as a percentage of load, by about 5 and 4%. Only 19% of the TN hybrid model coefficients and just 2% of the TP hybrid model coefficients show evidence of substantial regional specificity (more than ±100% deviation from the national model estimate). The hybrid models have much greater precision in the estimated coefficients than do the unconstrained regional models, demonstrating the efficacy of pooling information across regions to improve regional models.     

Stationarity of Streamflow Records and Their Influence on Bankfull Regional Curves1

Haucke, Jessica and Katherine A. Clancy, 2011. Stationarity of Streamflow Records and Their Influence on Bankfull Regional Curves. Journal of the American Water Resources Association (JAWRA) 47(6):1338–1347. DOI: 10.1111/j.1752‐1688.2011.00590.x Abstract: Bankfull regional curves, which are curves that establish relationships among channel morphology, discharge, drainage area, are used extensively for stream restoration. These curves are developed upon the assumption that streamflows maintain stationarity over the entire record. We examined this assumption in the Driftless Area of southwestern Wisconsin where agricultural soil retention practices have changed, and precipitation has increased since the 1970s. We developed a bankfull regional curve for this area using field surveys of bankfull channel performed during 2008‐2009 and annual series of peak streamflows for 10 rivers with streamflow records ranging from the 1930s to 2009. We found bankfull flows to correlate to a 1.1 return period. To evaluate gage data statistics, we used the sign test to compare our channel morphology to historic 1.5 return period discharge (Q_1.5) for five time periods: 1959‐1972, 1973‐1992, 1993‐2008, 1999‐2008, and the 1959‐2008 period of record. Analysis of the historic gage data indicated that there has been a more than 30% decline in Q_1.5 since 1959. Our research suggests that land conservation practices may have a larger impact on gaging station stationarity than annual precipitation changes do. Additionally, historic peak flow data from gages, which have records that span land conservation changes, may need to be truncated to represent current flow regimes.     

The Impacts of Water Conservation Strategies on Water Use: Four Case Studies1

Tsai, Yushiou, Sara Cohen, and Richard M. Vogel, 2011. The Impacts of Water Conservation Strategies on Water Use: Four Case Studies. Journal of the American Water Resources Association (JAWRA) 47(4):687‐701. DOI: 10.1111/j.1752‐1688.2011.00534.x Abstract: We assessed impacts on water use achieved by implementation of controlled experiments relating to four water conservation strategies in four towns within the Ipswich watershed in Massachusetts. The strategies included (1) installation of weather‐sensitive irrigation controller switches (WSICS) in residences and municipal athletic fields; (2) installation of rainwater harvesting systems in residences; (3) two outreach programs: (a) free home indoor water use audits and water fixture retrofit kits and (b) rebates for low‐water‐demand toilets and washing machines; and (4) soil amendments to improve soil moisture retention at a municipal athletic field. The goals of this study are to summarize the effectiveness of the four water conservation strategies and to introduce nonparametric statistical methods for evaluating the effectiveness of these conservation strategies in reducing water use. It was found that (1) the municipal WSICS significantly reduced water use; (2) residences with high irrigation demand were more likely than low water users to experience a substantial demand decrease when equipped with the WSICS; (3) rainwater harvesting provided substantial rainwater use, but these volumes were small relative to total domestic water use and relative to the natural fluctuations in domestic water use; (4) both the audits/retrofit and rebate programs resulted in significant water savings; and (5) a modeling approach showed potential water savings from soil amendments in ball fields.     

Double-dipping in environmental markets

There is an increasing tendency to use markets to induce the provision of environmental services. As such markets increase in scope, potential market participants might sell multiple environmental services. The question we consider here is whether participants in such markets should be allowed to sell credits in more than one market simultaneously. Some have argued in favor of such “double-dipping”, because it would make the provision of environmental services more profitable. In practice however, most programs do not allow double-dipping. We show that if the optimal level of pollution abatement is sought, then double-dipping maximizes societal net benefits. However, if pollution policies are set in a piecemeal fashion, then the caps for each market are unlikely to be optimal and, in this second-best setting, a policy prohibiting double-dipping can lead to greater social net benefits. We explore conditions under which a single-market policy is preferred, or equivalently, where piecemeal policies are likely to yield particularly inefficient outcomes.     

近十年我国安全系统工程学发展研究综述

安全系统工程学是近几年发展起来的新兴学科,作为我国安全工程专业专业课设置中的一个重要内容,其地位显得越来越重要。为了了解和掌握近年我国安全系统工程学的研究进展,用文献统计的方法对近十年（2000-2009年）中国期刊全文数据库、中国优秀硕士学位论文全文数据库、中国博士学位论文全文数据库等收录的关于安全系统工程学方面的论文进行检索;分析、比较统计的结果后发现,近十年我国安全系统工程学发展迅速并有逐年上升趋势,期间安全系统工程学自身内容也逐步发展完善,其研究领域广泛分布于其他各领域学科中,该阶段安全系统工程学的研究内容主要集中于系统安全分析和安全评价上。根据统计结果以及现阶段我国安全系统工程学的发展现状,结合安全科学和系统工程的知识对今后学科发展提出建议。     

苏州城区路面降雨径流污染特征分析研究

通过对苏州典型商住区和文教区路面径流水质的采样分析探讨了道路降雨径流的污染特征.结果显示不同功能区径流水质差异较大,商住区各污染物浓度均高于文教区.径流污染物浓度一般在降雨初期较高,往后逐渐下降并趋于平稳.SS和COD、Pb等都有较强的相关性.各污染物的初期效应明显,商住区初始冲刷效应较强;重金属物质的冲刷强度要大于其他污染物.降雨强度是影响初始冲刷效应的主要因素,强度较大的降雨初期冲刷效应明显.     

福建省环保投资对工业废水污染控制的影响分析

依据福建省2006-2011年环保投资的相关统计数据,对水污染治理投资和工业废水污染控制的关系进行深入分析,结果表明单位GDP水污染治理投资与工业废水排放量之间呈负相关。并指出福建省环境污染治理投资总量不足,单位GDP水污染治理投资比例偏低等问题,并针对这些问题提出应制定水污染治理投资规划,发展生态生产力并实施过程治理投资,使水污染得到真正有效的控制。     

应急管理综合统计指标体系设计与构建——基于北京市应急管理实践探索

为解决我国近些年应急管理体制改革背景下出现的现行统计指标与现行应急管理职责职能不匹配、业务需求不协调的问题,更好地适应我国应急管理新形势新任务新要求,在梳理北京市应急管理综合统计指标体系演化脉络的基础上,从应急管理业务职能入手,构建包含3个层级、11大类、523项统计指标的应急管理综合统计指标体系及相关工作机制,且经过北京多年的实践应用和持续改进表明,该综合统计指标体系具有较好的科学性和适用性,对其他同类应急管理主体单位的综合统计指标体系建立具有一定的启示和借鉴作用。     

Destruction of 4-phenolsulfonic acid in water by anodic contact glow discharge electrolysis

Destruction of 4-phenolsulfonic acid (4-PSA) in water was carried out using anodic contact glow discharge electrolysis. Accompanying the decay of 4-PSA, the amount of total organic carbon (TOC) in water correspondingly decreased, while the sulfonate group of 4- PSA was released as sulfate ion. Oxalate and formate were obtained as minor by-products. Additionally, phenol, 1,4-hydroquinone, hydroxyquinol and 1,4-benzoquinone were detected as primary intermediates in the initial stages of decomposition of 4-PSA. A reaction pathway involving successive attacks of hydroxyl and hydrogen radicals was assumed on the basis of the observed products and kinetics. It was revealed that the decay of both 4-PSA and TOC obeyed a first-order rate law. The effects of different Fe ions and initial concentrations of 4-PSA on the degradation rate were investigated. It was found that the presence of Fe ions could increase the degradation rate of 4-PSA, while initial concentrations lower than 80 mmol/L had no significant effect on kinetic behaviour. The disappearance rate of 4-PSA was significantly affected by pH.