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571.
Assessment of municipal waste compost as a daily cover material for odour control at landfill sites 总被引:6,自引:0,他引:6
Hurst C Longhurst P Pollard S Smith R Jefferson B Gronow J 《Environmental pollution (Barking, Essex : 1987)》2005,135(1):171-177
The ability of municipal waste compost as a daily cover material to reduce the odorous emissions associated with landfill surfaces was investigated. Trials were carried out using landfill gas, a certified sulphurous gas mix and ambient air as a control. Odorous gas was passed through portable test column filled with compost at different densities (590 kg/m3 and 740 kg/m3). Gas samples were taken from the inlet, outlet and at varying column depths and examined using a combination of sensory analysis (olfactometry) and a novel analytical method (Transportable Selected Ion Flow Tube--TSIFT). Results for the trials using landfill gas showed a 69% odour reduction (OU/m3) through the column for compost with a bulk density of 590 kg/m3, and a reduction of 97% using compost with a bulk density of 740 kg/m3. TSIFT analysis showed an overall decrease in the concentration of terpenes, and sulphurous compounds in the outlet gas from the column for both bulk densities. No significant trend could be identified for the concentrations at different depths within the column. Results show the ability of compost to reduce landfill odours under differing conditions. The inconclusive data provided by TSIFT analysis may be due to the analysis of compounds that are not contributing to odour, and thus highlights the potential for synergetic effects and the importance of sensory measurement when examining odorous emissions. 相似文献
572.
Fenhuan Yang Chui Fong Lau Viki Wai Ting Tong Kiwi Kai Zhang Dane Westerdahl Simon Ng 《Journal of the Air & Waste Management Association (1995)》2019,69(1):47-57
Metropolitan residents are concerned about their exposure to airborne pollutants. But establishing these exposures is challenging. A compact personal exposure kit (PEK) was developed to evaluate personal integrated exposure (PIE) from time-resolved data to particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5) in five microenvironments, including office, home, commuting, other indoor activities (other than home and office), and outdoor activities experienced both on weekdays and weekends. The study was conducted in Hong Kong. The PEK measured PM2.5, reported location and several other factors, stored collected data, as well as reported the data back to the investigators using global system for mobile communication (GSM) telemetry. Generally, PM2.5 concentrations in office microenvironment were found to be the smallest (13.0 μg/m3), whereas the largest PM2.5 concentration microenvironments were experienced during outdoor activities (54.4 μg/m3). Participants spent more than 85% of their time indoors, including in offices, homes, and other public indoor venues. On average, 42% and 81% of the time were spent in homes, which contributed 52% and 79% of PIE (during weekdays and weekends, respectively), suggesting that improvement of air quality in homes may reduce overall exposures and indicating the need for actions to mitigate possible public health burdens in Hong Kong. This study also found that various indoor/outdoor microenvironments experienced by urban office workers cannot be accurately represented by general urban air quality data reported from the regulatory monitoring. Such personalized air quality information, especially while in transit or in offices and homes, may provide improved information on population exposures to air pollution.
Implications: A newly developed personal exposure kit (PEK) was used to monitor PM2.5 exposure of metropolitan citizens in their daily life. Different microenvironments and time durations caused various personal integrated exposure (PIE). The stationary monitoring method for PIE was also compared and evaluated with PEK. Positive protection actions can be taken after understanding the major contribution to PM2.5 exposure. 相似文献
573.
Polycyclic aromatic hydrocarbons (PAHs) are of environmental concern because many PAHs are either carcinogens or potential carcinogens. Petroleum products are a major source of PAHs. The occurrence of PAH contamination is widespread and novel treatment technologies for the remediation of contaminated soils are necessary.Ozone has been found to be extremely useful for the degradation of PAHs in soils. For these compounds, the reaction with molecular ozone appears to be the more important degradation pathway. Greater than 95% removal of phenanthrene was achieved with an ozonation time of 2.3 h at an ozone flux of 250 mg h−1. After 4.0 h of treatment at an ozone flux of 600 mg h−1, 91 % of the pyrene was removed. We have also found that the more hydrophobic PAHs (e.g. chrysene) react more slowly than would be expected on the basis of their reactivity with ozone, suggesting that partitioning of the contaminant into soil organic matter may reduce the reactivity of the compound. Even so, after 4 h of exposure to ozone, the chrysene concentration in a contaminated Metea soil was reduced from 100 to 50 mg kg−1 .Ozone has been found to be readily transported through columns packed with a number of geological materials, including Ottawa sand, Metea soil, Borden aquifer material and Wurtsmith aquifer material. All of these geological materials exerted a limited (finite) ozone demand, i.e. the rate of ozone degradation in soil columns is very slow after the ozone demand is met. Moisture content was found to increase the ozone demand, most likely owing to the dissolution of gaseous ozone into the pore water. As once the initial ozone demand is met, little degradation of ozone is observed, it should be possible to achieve ozone penetration to a considerable distance away from the injection well, suggesting that in-situ ozonation is a feasible means of treating uncontaminated unsaturated soils. This is substantiated by two field studies where in-situ ozonation was apparently successful at remediating the sites. 相似文献
574.
Smith EJ Hughes S Lawlor AJ Lofts S Simon BM Stevens PA Stidson RT Tipping E Vincent CD 《Environmental pollution (Barking, Essex : 1987)》2005,136(1):11-18
Four samples of ombrotrophic peat were collected from each of 10 upland locations in a transect from the southern Pennines to the Highland Boundary Fault, a total distance of ca. 400 km. Bulk compositions and other properties were determined. Total contents of Al and heavy metals (Ni, Cu, Zn, Cd, Pb) were determined following digestion with hydrofluoric acid, and concentrations of metals extractable with dilute nitric acid were also measured. Supernatants obtained from aqueous extractions of the peat samples were analysed for pH, major cations and anions, dissolved organic carbon and dissolved metals, and concentrations of free metal ions (Al(3+), Ni(2+), etc.) were estimated by applying a chemical speciation model. Both total and HNO(3)-extractable metal concentrations varied along the transect, the highest values being found at locations close to industrial and former mining areas. The HNO(3)-extractable soil metal contents of Ni, Cu and Cd were appreciably lower than lowest-observed-effect-concentrations (LOEC) for toxicity towards microorganisms in acid, organic rich soils. However, the contents of Zn at two locations, and of Pb at five locations exceeded LOECs, suggesting that they may be exerting toxic effects in the peats. Soil solution concentrations of free heavy metal ions (Cu(2+), Zn(2+), Cd(2+), Pb(2+)) were substantially lower than LOECs for toxicity towards vascular plants, whereas concentrations of Al(3+) were near to toxic levels at two locations. 相似文献
575.
Samples collected in the Irminger Basin during the Marine Productivity Programme (2001–2004) were used to study Calanus finmarchicus vertical distribution and histological changes of its mid-gut epithelium in relation to overwintering strategy. Previous
studies have shown that cell composition of the glandular part of the mid-gut, size and abundance of B cells responsible for
digestive enzyme secretion and thickness of the epithelium could be good indicators of individual physiological state. We
used C. finmarchicus abundance, vertical distribution, lipid sac volume and mid-gut epithelium histological composition of individuals collected
in contrasting hydrographic areas of the Irminger Basin and sampled at different seasons to understand C. finmarchicus life cycle in the Irminger Basin. Lipid sac volumes were significantly different between the seasons but neither between
the hydographic areas nor the various depths of the water column. B cells concentrations and thickness of the epithelium have
allowed us to distinguish a non-diapausing surface population (350 m) in the East Greenland Current while individuals at depth
(1,250 m) were overwintering. This result is correlated by a bimodal vertical distribution of the CV in this biozone. In the
other hydrographic areas, all CV were dormant, although surface individuals were not analysed in the Southern Irminger Current. 相似文献
576.
577.
Andrew Simon Natasha Pollen Eddy Langendoen 《Journal of the American Water Resources Association》2006,42(1):99-113
Over the past 35 years, a trend of decreasing water clarity has been documented in Lake Tahoe, attributable in part to the delivery of fine grained sediment emanating from upland and channel erosion. A recent study showed that the Upper Truckee River is the single largest contributor of sediment to Lake Tahoe, with a large proportion of the sediment load emanating from streambanks. This study combines field data with numerical modeling to identify the critical conditions for bank stability along an unstable reach of the Upper Truckee River, California. Bank failures occur during winter and spring months, brought on by repeated basal melting of snow packs and rain‐on‐snow events. Field studies of young lodgepole pines and Lemmon's willow were used to quantify the mechanical, hydrologic, and net effects of riparian vegetation on streambank stability. Lemmon's willow provided an order of magnitude more root reinforcement (5.5 kPa) than the lodgepole pines (0.5 kPa); the hydrologic effects of the species varied spatially and temporally and generally were of a smaller magnitude than the mechanical effects. Overall, Lemmon's willow provided a significant increase in bank strength, reducing the frequency of bank failures and delivery of fine grained sediment to the study reach of the Upper Truckee River. 相似文献
578.
579.
580.
Environmental impact assessment in the People's Republic of China: a case study of the Shanghai Second Sewerage Project 总被引:2,自引:0,他引:2
In March 1994, China announced its plans for sustainable development in a White Paper entitled 'China's Strategy for Population, Environment and Development in the 21st Century. To achieve the objective of sustainable development; economic, social and environmental aims have to be consistent with each other and meet the needs of the present, without compromising the ability of future generations to meet their own needs. Sustainable development, therefore, encompasses many 'ideals, which need to be introduced through practical management techniques. This paper addresses the role that EIA could play in promoting sustainable development projects in the People's Republic of China by way of the detailed examination of a case study—the Shanghai Second Sewerage Project. 相似文献