Comparison among model estimates of critical loads of acidic deposition using different sources and scales of input data

The critical load (CL) of acidic atmospheric deposition represents the load of acidity deposited from the atmosphere to the earth’s surface at which harmful acidification effects on sensitive biological receptors are thought to occur. In this study, the CL for forest soils was estimated for 27 watersheds throughout the United States using a steady-state mass balance approach based on both national and site-specific data and using different approaches for estimating base cation weathering. Results suggested that the scale and source of input data can have large effects on the calculated CL and that the most important parameter in the steady-state model used to estimate CL is base cation weathering. These results suggest that the data and approach used to estimate weathering must be robust if the calculated CL is to be useful for its intended purpose.     

Carbon/nitrogen ratio as a major factor for predicting the effects of organic wastes on soil bacterial communities assessed by DNA-based molecular techniques

Background, aim, and scope  

Current Australian legislation permits the beneficial application of grease trap waste (GTW) to agricultural soil, viewing it as a beneficial source of organic matter and soil conditioner containing no/low amounts of metals or pathogenic organisms. However, little is known about the influence of GTW on soil bacterial community. A field experiment was established at Menangle in south western Sydney in Australia to quantitatively assess the impacts of different types (GTW CO and GTW CL) and amounts of GTW application on the soil bacterial community and diversity. Furthermore, a municipal solid waste (MSW) compost was simultaneously examined to compare against the other organic wastes. Knowledge about the shifts in microbial community structure and diversity following the applications of organic wastes could help to evaluate the ecological consequences on the soil and thus to develop sound regulatory guidelines for the beneficial reuse of organic wastes in agricultural lands.     

A time series analysis of environmental and metrological factors impact on cutaneous leishmaniasis incidence in an endemic area of Dehloran,Iran

The aim of this study was to investigate the relationship between the environmental and metrological variables and cutaneous leishmaniasis (CL) transmission and its prediction in a region susceptible to this disease prevalence using a time series model. The accurate locations of 4437 CL diagnosed from 2011 to 2015 were obtained to be used in the time series model. Temperature, number of days with temperature over 30 °C, and number of earthquake were related to CL incidence using the Seasonal Auto-correlated Integrated Moving Average (SARIMA) model according to the Box-Jenkins method. In addition, the relationship between land use and surface soil type in 500- and 1000-m radius around the CL patients were investigated. The SARIMA models showed significant associations between environmental and meteorological variables and CL incidence adjusted for seasonality and auto-correlation. The result indicated that there are need more robust preventive programs in earthquake-prone areas with high temperature and inceptisol soil type than other areas. In addition, the region with these characteristics should be considered as high-risk areas for CL prevalence.     

Determining the equilibrium partitioning coefficients of volatile organic compounds at an air-water interface

The single equilibration technique (SET) was adopted to determine the partitioning coefficients (pc) at an air-water interface for volatile organic compounds (VOCs), including ethanol, iso-propanol (IPA), iso-butanol (IBA), methyl ethyl ketone (MEK) and toluene, all extensively used in industrial processes. Standard SET procedures were established. The liquid concentrations (CL) of tested VOCs ranged from 10 to 125 mg l(-1) for alcohols and MEK, and from 0.5 to 20 mg l(-1) for toluene. The temperatures (Tw) of aqueous VOC solutions were maintained at 27, 32, 38 and 42 degrees C to determine the gaseous concentrations at equilibrium (Cg*) and pc of VOCs, using the formula pc=(Cg*/CL). Results reveal that the pc values of all tested components increase slowly with Tw given a constant CL, and that the pc of alcohols and MEK fall as CL increases at a constant Tw. In contrast, the pc of toluene is not significantly impacted by a variation in CL at a constant Tw. However, the effect of CL concentration has seldom been discussed. The heats of liquid and gaseous phase transfer (DeltaHtr) of VOC, and the highly linear regression (with squared correlation coefficients, R2, from 0.901 to 0.999) between lnCg* and Tw(-1) are also evaluated. The experimental results and the VOC mass transfer characteristics are helpful for evaluating the emission of VOC from the water surface of wastewater treatment facilities.     

洗像废液的分质处理

对洗像过程中产生的洗像废液按照成分的不同进行分质处理。其中 ,有机废液采用高温焚烧的方法进行处理 ;无机废液根据主要成分的化学性质分别采用中和、氧化等方法进行处理。通过室内试验 ,确定了处理工艺的主要参数 ,并根据试验结果 ,利用废液处理站设施处理了 1.6 4t洗像废液。处理后排放的废水、废气均达到了国家有关排放标准     

Medical Waste Treatment and Disposal Methods Used by Hospitals in Oregon,Washington, and Idaho

ABSTRACT

This study investigated medical waste practices used by hospitals in Oregon, Washington, and Idaho, which includes the majority of hospitals in the U.S. Environmental Protection Agency's (EPA) Region 10. During the fall of 1993, 225 hospitals were surveyed with a response rate of 72.5%. The results reported here focus on infectious waste segregation practices, medical waste treatment and disposal practices, and the operating status of hospital incinerators in these three states. Hospitals were provided a definition of medical waste in the survey, but were queried about how they define infectious waste. The results implied that there was no consensus about which agency or organization's definition of infectious waste should be used in their waste management programs. Confusion around the definition of infectious waste may also have contributed to the finding that almost half of the hospitals are not segregating infectious waste from other medical waste. The most frequently used practice of treating and disposing of medical waste was the use of private haulers that transport medical waste to treatment facilities (61.5%). The next most frequently reported techniques were pouring into municipal sewage (46.6%), depositing in landfills (41.6%), and autoclaving (32.3%). Other methods adopted by hospitals included Electro-Thermal-Deac-tivation (ETD), hydropulping, microwaving, and grinding before pouring into the municipal sewer. Hospitals were asked to identify all methods they used in the treatment and disposal of medical waste. Percentages, therefore, add up to greater than 100% because the majority chose more than one method. Hospitals in Oregon and Washington used microwaving and ETD methods to treat medical waste, while those in Idaho did not. No hospitals in any of the states reported using irradiation as a treatment technique. Most hospitals in Oregon and Washington no longer operate their incinerators due to more stringent regulations regarding air pollution emissions. Hospitals in Idaho, however, were still operating incinerators in the absence of state regulations specific to these types of facilities.     

The Influence of Flame-Generated Free Radicals on the Thermal Oxidation of Waste Gases

Studies of the thermal oxidation of waste gases were carried out in two variants. During the first, the destruction of waste gases was facilitated by hydrogen flame-generated radicals. During the other variant, this flame was not used, but the same temperature was maintained as in the first one. The waste gases used were mixtures of toluene with air and methane with air of 200 and 400 ppm concentrations, respectively. The experiments were performed in a flow reactor within the temperature range of 800 to 1330 K. The efficiency of oxidation of methane and toluene obtained during the first variant was considerably higher than that obtained in the second one. This was due to the promotional effect of the hydrogen flame.     

Response of foodborne Salmonella spp. marker strains inoculated on egg shell surfaces to disinfectants in a commercial egg washer.

The objective of this study was to determine the effectiveness of an iodine based disinfectant (IBD, Iocide, Biomedical Development Corporation, San Antonio, TX) on Salmonella enteritidis and S. typhimurium inoculated on egg shell surfaces under simulated industry egg processing conditions with a commercial egg washer used as the sanitizer delivery system. Re-circulated egg washer water containing 1.40-2.85 g/l total dissolved solids was obtained from a commercial egg processing. Sanitizing treatments consisted of distilled deionized water (DDW), IBD, and chlorine (CL; 200 ppm). All treatments (DDW, IBD and CL) significantly (p < 0.05) decreased Salmonella spp. populations on the shell compared to dry (no spray) egg controls. However, efficacy of egg sanitizers appeared to be dependent on the level of total dissolved solids in the egg wash water.     

Laser cleaning of historical limestone buildings in Bordeaux appraisal using cathodoluminescence and electron paramagnetic resonance

BACKGROUND: Most historical buildings in Bordeaux city are made of limestone. This yellowish-white rock is rather porous and highly sensitive to pollution. As a consequence of local weathering conditions, these buildings present a dark appearance due to the development of a superficial dark grey to black crust. METHODS: For the last decade, a campaign has been underway to clean these buildings. Eleven techniques of surface treatment have been used, including laser beam technology. As a contribution to the study of laser beam effects on stone buildings, two analytical methods have been used on clean versus unclean surfaces: Cathodoluminescence (CL) and Electron Paramagnetic Resonance (EPR), in addition to SEM-EDX and XRD. RESULTS: The black crust is composed of different types of particles: carbon porous micro-particles of industrial origin, atmospheric dust due to the erosion of soils and rocks, alumino-silicate particles from urban pollution; all these particles being cemented by gypsum. DISCUSSION: As far as heritage conservation is concerned, the laser surface treatment not only preserves the original patina of the stone, but also leaves surface smoothness unaltered. CONCLUSIONS AND PERSPECTIVES: CL and EPR data confirm that lasers--with highly controlled parameters--only get rid of the black crust and, thus, reveal the underneath layer, the so-called patina. This patina shows no luminescence, whereas the limestone on which it has grown shows a bright orange emission of CL. This indicates CL to be a fast and easy way to provide a high quality control for the restoration of polluted ancient stones.     

Determination of picogram quantities of chlortoluron in soil samples by luminol–chitosan chemiluminescence system

Based on the enhancing effect of chitosan (CS) on luminol-dissolved oxygen chemiluminescence (CL) reaction, a flow injection (FI) luminol–CS CL system was established. It was found that the increase of CL intensity was proportional to the concentrations of CS ranging from 0.7 to 10.0 μmol l^?1. In the presence of chlortoluron (CTU), the CL intensity of luminol–CS system could be obviously inhibited and the decrements of CL intensity were linearly proportional to the logarithm of CTU concentrations ranging from 0.01 to 70.0 ng ml^?1, giving the limit of detection 3.0 pg ml^?1 (3σ). At a flow rate of 2.0 ml min^?1, the whole process including sampling and washing could be accomplished within 36 s, offering a sample throughput of 100 h^?1. The proposed FI–CL method was successfully applied to the determination of CTU in soil samples with recoveries ranging from 95.0 % to 105.3 % and the relative standard deviations (RSDs) of less than 4.0 %.     

城市生活垃圾渗透系数测试研究

采用常水头测渗实验,对不同压实密度和水力梯度下的新鲜垃圾与陈垃圾的渗透系数进行测试,根据达西定律求得渗透系数值。由于垃圾的不均匀性、小颗粒的运动和大孔隙沟道流的形成和改变,实验初始阶段渗透系数值先增大至峰值,然后缓慢降低直至趋于稳定。实验稳定后,新鲜垃圾压实密度为0.75~0.95 t/m3时,渗透系数值约为1.26E-03~1.43E-03 cm/s。陈垃圾在压实密度分别为1.2和1.4 t/m3时,渗透系数为8.29E-04和1.35E-04 cm/s。     

含油固体废弃物综合利用技术的研究

就油田含油固体废弃物的存放及其对周边环境存在的潜在隐患 ,全面分析了该废弃物的组成与成分 ,并介绍了几种可用于石油污染土壤治理技术的方法特点 ,尤其是针对这种固体含量和油分含量皆较高的含油固体废弃物 ,开展了综合利用治理技术方面的试验 ,以固体废弃物细粉作为制砖助燃配料成分 ,考查了砖块质量与细粉掺入量及其他因素之间的关系 ,取得了较好的效果     

放射性废物处置库顶盖毛细屏障的研究进展

放射性废物处置库工程屏障的设计对处置库中放射性废物的长期安全具有重要意义.毛细屏障作为处置库顶盖的工程屏障之一,已在国内外得到广泛的应用.阐述了放射性废物处置库顶盖毛细屏障设置的意义,对近年来毛细屏障的一些研究进展进行了分析,提出了一些尚待解决的问题.     

医疗废物排放统计变量的选择及排放系数的确定

为解决医疗行业废物排放量核定难的问题，通过对医疗机构废物产生量的调查、统计、分析，在确定医疗废物排放统计变量的基础上，得出相应的医疗废物排放系数，以供排污申报医疗废物排放量的核定。     

An activated sludge process to reduce the pollution load of a dye-industry waste

A laboratory-scale activated sludge process was developed to reduce the pollution load of a dye-industry waste, containing aniline, phenol, methyl violet and rhodamine B as its major components. The waste exerted an organic load of 5576 mg litre(-1) as the chemical oxygen demand (COD), of 896 mg litre(-1) as total organic carbon (TOC), and had a 31.5 mg litre(-1) phenol content. A microbial sludge, capable of growing on the waste, was developed from cattle dung, adapted to the waste and used as a bioinoculum for the process. This resulted in reductions of 60% in COD, 37% in TOC, and 92% in phenol content, and a decrease in optical density of the colour of the waste from an initial 0.915 to 0.360 at 580 nm. Microorganisms isolated from sludge were identified as Pseudomonas alcaligenes and P. mendocina.     

印染行业热定型机油烟废气检测方法研究

建立了粘胶基活性炭纤维吸附-正己烷萃取-紫外分光光度法检测热定型机油烟废气的方法,以印染厂实际热定型机油烟废气萃取液为标准油烟,在230 nm处测吸光度,绘制标准曲线,相关系数为0.999 7.实验结果表明,正己烷1次萃取率超过了90%,紫外分光光度法标准偏差为0.344～0.693,相对标准偏差在5%内,平均加标回收率为93%～98%,方法检出限为0.829 mg/L.粘胶基活性炭纤维耐高温,对0～100 mg/L的热定型机油烟废气的饱和吸附量为1.0～2.5 g/g.用Langmuir、Freundlich和DR方程对实验吸附等温线进行了拟合,低油烟浓度时Langmuir方程拟合较好,高浓度油烟时DR方程拟合较好.     

Hazardous wastes and economic risk reduction: case study, Poland

A concise summary balance of industrial and hazardous waste is given, reflecting the situation in Poland. Nearly 130 million tonnes of waste were generated annually in the past in more than 1300 larger industrial plants. Approximately 1800 million tonnes of industrial waste is already stockpiled. The amount of hazardous waste generated per year was 0.3 and 1.0 million tonnes of the first and second class of toxicity, respectively. Seventeen existing on-site incinerators cannot treat the whole amount of solid and hazardous waste generated. Therefore, landfilling is still the most widely used method of waste disposal. Decontamination of the abandoned areas left by the Soviet Army, and reclamation of some hundreds of storage sites filled with outdated pesticides are now added to the national plan of waste management. Its implementation, including introduction of the best available and best managed technologies of hazardous waste treatment and disposal, will take at least 20 to 30 years.     

Canopy leaching of nutrients and metals in a mountain spruce forest

Precipitation and throughfall fluxes of major ions, nutrients (C, N, P), and metals (Al, Fe, Mn), and the chemical composition of litter fall and living plant tissue in Norway spruce stands (the Bohemian Forest; Czech Republic), were used to evaluate how microbial processes and decay of plant tissue in canopies influence canopy leaching (CL) of elements. Proton exchange for Mg²⁺, Ca²⁺, and K⁺ in decaying biomass and co-transport of Ca²⁺ and K⁺ out of plant cells with organic acid anions were the most likely processes contributing to CL of base cations. The CL of total P and N (and also NO₃^?) was minor. Important proportions of the N and P mineral forms were transformed to organic forms by microbial processes (primary and bacterial production), with the respective CL of ?13.9 and 16.4 mmol m^?2 yr^?1 for NH₄⁺ and organic N, and ?0.33 and 0.22 mmol m^?2 yr^?1 for dissolved reactive P (DRP) and organic P. Most of particulate P and N in throughfall (～90%) originated from microbial DRP and NH₄⁺ transformations, but particulate C mostly came from the fragmentation of plant tissue (58%). Among metals, CL was not observed for Al, was small for Fe (0.3 mmol m^?2 yr^?1), and greatest for Mn (0.9 mmol m^?2 yr^?1) due to leaching from decaying tissue by acidic precipitation.     

印刷用铝基材碱洗废液的循环利用

对印刷用铝基材碱洗废液进行了循环利用研究。首先将高COD含量的碱洗废液进行除油脱色处理,通过石灰和硬脂酸的协同效应,使COD含量从26300mg／L降至480mg／L,色度降至60°;然后利用含铝碱性废液通过碳化法制备出结晶度66％的拟薄水铝石产品;最后对分离后的碱性废水按配方要求配制,对铝基材进行除油实验,经5次循环表明,除油效果和对铝基材的腐蚀率均100％达标。     

Combustion of brominated flame retardants and behavior of its byproducts

The substance flow rate of PBDDs/DFs into flue gas and incineration residues from incineration of three types of waste samples containing brominated flame retardants were examined. The samples used consisted of PBDEs (a typical retardant), used TV casing materials (actual waste materials), and waste printed circuit boards. PBDDs/DFs concentrations in the experimental samples of PBDEs/PE, waste TV casing materials and printed circuit boards ranged between 3000 and 130,000 ng/g. These values are very high when compared to other investigations. The increase of chlorine concentration in input sample reduced the ratio of PBDDs/DFs in flue gas and raised the ratio of PCDDs/DFs. With adequate combustion control and flue gas treatment, the amount of PBDDs/DFs released from the incineration of resin containing brominated flame retardants was lower than the input amount. The presence of PBDDs/DFs in incineration residues dominated the total amount of dioxins released. When PBDDs/DFs, PCDDs/DFs and PXDDs/DFs were considered as a total, the total amount released was lower than the total amount input.