Estimation and comparison of night-time OH levels in the UK urban atmosphere using two different analysis methods

Night-time OH levels have been determined for UK urban surface environments using two methods,the decay and steady state approximation methods.Measurement data from the UK National Environmental Technology Centre archive for four urban sites(Bristol,Harwell,London Eltham and Edinburgh) over the time period of 1996 to 2000 have been used in this study.Three reactive alkenes,namely isoprene,1,3-butadiene and trans-2-pentene were chosen for the calculation of OH levels by the decay method.Hourly measurements o...     

Abundance of denitrification genes under different peizometer depths in four Irish agricultural groundwater sites

This study examined the relationship between the abundance of bacterial denitrifiers in groundwater at four sites, differing with respect to overlaying land management and peizometer depth. Groundwater was sourced from 36 multilevel piezometers, which were installed to target different groundwater zones: (1) subsoil, (2) subsoil to bedrock interface, and (3) bedrock. The gene copy concentrations (GCCs), as gene copies per liter, for bacterial 16S rRNA genes and the denitrifying functional genes, nirK, nirS, and nosZ, were determined using quantitative polymerase chain reaction assays. The results were related to gaseous nitrogen emissions and to the physicochemical properties of the four sites. Overall, nirK and nirS abundance appeared to show no significant correlation to N₂O production (P?=?0.9989; P?=?0.3188); and no significant correlation was observed between nosZ and excess N₂ concentrations (P?=?0.0793). In the majority of piezometers investigated, the variation of nirK and nirS gene copy concentrations was considered significant (P?<?0.0001). Dissolved organic carbon (DOC) decreased with aquifer depth and ranged from 1.0–4.0 mg l^?1, 0.9–2.4 mg l^?1, and 0.8–2.4 mg l^?1 within piezometers located in the subsoil, subsoil/bedrock interface, and bedrock depths, respectively. The availability of increasing DOC and the depth of the water table were positively correlated with increasing nir and nosZ GCCs (P?=?0.0012). A significant temporal correlation was noted between nirS and piezometer depth (P?<?0.001). Interestingly, the nirK, nirS, and nosZ GCCs varied between piezometer depths within specific sites, while GCCs remained relatively constant from site to site, thus indicating no direct impact of agricultural land management strategies investigated on denitrifier abundance.     

Use of Membrane Collectors in Electrostatic Precipitators

ABSTRACT

Membrane collection surfaces, developed and patented by researchers at Ohio University, were used to replace steel plates in a dry electrostatic precipitator (ESP). Such replacement facilitates tension-based rapping, which shears the adhered particle layer from the collector surface more effectively than hammer-based rapping. Tests were performed to measure the collection efficiency of the membranes and to quantify the potential improvements of this novel cleaning technique with respect to re-entrainment. Results indicate that even semiconductor materials (e.g., carbon fibers) collect ash nearly as efficiently as steel plates, potentially indicating that collection surface resistivity is primarily dictated by the accumulated ash layer and not by the underlying plate conductivity. In addition, virtually all sheared particles separated from the collecting membranes fell within the boundary layer of the membrane, indicating extremely low potential for re-entrainment.     

Physicochemical characterization of industrial effluents and their effect on fish survival

Abstract

Water samples taken from selected industrial drainages and receiving streams in and around Islamabad, Pakistan, during the summers of 1987 to 1990 showed disturbances in pH and low oxygen levels. Selected metals (Fe, Pb, Zn, Cd, Cu, Ni, Hg) were higher in all effluents than in receiving waters. Static bioassays of the undiluted industrial effluents from three sites caused 100% mortality in carp during the first 24 hrs. Fishes also suffered 30 to 60% mortality when exposed to other undiluted industrial effluents and some mortality when industrial effluents were diluted by 50%.     

Application of enrichment factor,geoaccumulation index,and ecological risk index in assessing the elemental pollution status of surface sediments

Environmental Geochemistry and Health - Sediment can accumulate trace elements in the environment. This study profiled the magnitude of As, Ba, Cd, Co, Cu, Cr, Ni, Pb, Se, and Zn pollution in...     

Evaluation of fungal potentiality for bioconversion of domestic wastewater sludge

This study was undertaken to screen the filamentous fungi isolated from its relevant habitats (wastewater, sewage sludge and sludge cake) for the bioconversion of domestic wastewater sludge. A total of 35 fungal strains were tested against wastewater sludge (total suspended solids, TSS 1%-5% w/w) to evaluate its potentiality for enhancing the biodegradability and dewaterability using liquid state bioconversion(LSB) process. The strains were divided into five groups i. e. Penicillium, Aspergillus, Trichoderma, Basidiomycete and Miscellaneous, respectively. The strains WWZP1003, SCahmA103, SCahmT105 and PC-9 among their respective groups of Penicillium,Aspergillus, Trichoderma and Basidiomycete played potential roles in terms of separation (formation of pellets/flocs/filaments),biodegradation(removal of COD) and filtration(filterability) of treated domestic wastewater sludge. The Miscellaneous group was not considered due to its unsatisfactory results as compared to the other groups. The pH value was also influenced by the microbial treatment during fermentation process. The filterability of treated sludge was improved by fungal treatment, and lowest filtration time was recorded for the strain WWZP1003 and SCahmA103 of Penicillium and Aspergillus groups respectively compared with other strains.     

Gasification applicability study of polyurethane solid refuse fuel fabricated from electric waste by measuring syngas and nitrogenous pollutant gases

To recycle polyurethane foam waste generated from electric appliance recycling centers for use as fuel in a gasification process, polyurethane solid refuse fuel fabricated as pellets was analyzed for the characteristics of elemental composition, proximate analysis, heating value, and thermo-gravimetric testing. It has a high heating value of 29.06 MJ/kg with a high content of combustibles, which could be feasibly used in any thermal process. However, the nitrogen content, of up to 7 %, was comparably higher than for other fuels such as coal, biomass, and refuse-derived fuel, and may result in the emission of nitrogenous pollutant gases of HCN and NH₃. By conducting gasification experiments on polyurethane solid refuse fuel in a fixed-bed reactor, a syngas with a heating value of 9.76 kJ/m³ and high content of both H₂ and CO were produced with good gasification efficiency; carbon conversion 54 %, and cold gas efficiency 60 %. The nitrogenous pollutant gases in syngas were measured at the concentrations of 160 ppm hydrogen cyanide and 40 ppm ammonia, which may have to be reduced using proper cleaning technologies prior to the commercialization of gasification technology for polyurethane waste.     

Space-time Bayesian small area disease risk models: development and evaluation with a focus on cluster detection

This paper extends the spatial local-likelihood model and the spatial mixture model to the space-time (ST) domain. For comparison, a standard random effect space-time (SREST) model is examined to allow evaluation of each model’s ability in relation to cluster detection. To pursue this evaluation, we use the ST counterparts of spatial cluster detection diagnostics. The proposed criteria are based on posterior estimates (e.g., misclassification rate) and some are based on post-hoc analysis of posterior samples (e.g., exceedance probability). In addition, we examine more conventional model fit criteria including mean square error (MSE). We illustrate the methodology with a real ST dataset, Georgia throat cancer mortality data for the years 1994–2005, and a simulated dataset where different levels and shapes of clusters are embedded. Overall, it is found that conventional SREST models fair well in ST cluster detection and in goodness-of-fit, while for extreme risk detection the local likelihood ST model does best.