Oil production operations produce waste fluids that may be stored in pits, open tanks, and other sites accessible to wildlife.
Birds visit these fluid-filled pits and tanks (“oil pits”), which often resemble water sources, and may become trapped and
die. The US Fish and Wildlife Service (USFWS) has a program to reduce these impacts by locating problem pits, documenting
mortality of protected wildlife species, and seeking cleanup or corrective action at problem pits with the help of state and
federal agencies regulating the oil industry. Species identification and verification of protected status for birds recovered
from oil pits are performed at the USFWS National Fish and Wildlife Forensics Laboratory. From 1992 to 2005, a minimum of
2060 individual birds were identified from remains recovered from oil pits, representing 172 species from 44 families. The
taxonomic and ecological diversity of these birds indicates that oil pits pose a threat to virtually all species of birds
that encounter them. Ninety-two percent of identified bird remains belonged to protected species. Most remains identified
at the Forensics Laboratory were from passerines, particularly ground-foraging species. Based on Forensics Laboratory and
USFWS field data, oil pits currently cause the deaths of 500,000–1 million birds per year. Although law enforcement and industry
efforts have produced genuine progress on this issue, oil pits remain a significant source of mortality for birds in the United
States. 相似文献
The paper describes the analysis of the potential effects of releases from compressed gaseous hydrogen systems on commercial vehicles in urban and tunnel environments using computational fluid dynamics (CFD). Comparative releases from compressed natural gas systems are also included in the analysis.
This study is restricted to typical non-articulated single deck city buses. Hydrogen releases are considered from storage systems with nominal working pressures of 20, 35 and 70 MPa, and a comparative natural gas release (20 MPa). The cases investigated are based on the assumptions that either fire causes a release via a thermally activated pressure relief device(s) (PRD) and that the released gas vents without immediately igniting, or that a PRD fails. Various release strategies were taken into account. For each configuration some worst-case scenarios are considered.
By far the most critical case investigated in the urban environment, is a rapid release of the entire hydrogen or natural gas storage system such as the simultaneous opening of all PRDs. If ignition occurs, the effects could be expected to be similar to the 1983 Stockholm hydrogen accident [Venetsanos, A. G., Huld, T., Adams, P., & Bartzis, J. G. (2003). Source, dispersion and combustion modelling of an accidental release of hydrogen in an urban environment. Journal of Hazardous Materials, A105, 1–25]. In the cases where the hydrogen release is restricted, for example, by venting through a single PRD, the effects are relatively minor and localised close to the area of the flammable cloud. With increasing hydrogen storage pressure, the maximum energy available in a flammable cloud after a release increases, as do the predicted overpressures resulting from combustion. Even in the relatively confined environment considered, the effects on the combustion regime are closer to what would be expected in a more open environment, i.e. a slow deflagration should be expected.
Among the cases studied the most severe one was a rapid release of the entire hydrogen (40 kg) or natural gas (168 kg) storage system within the confines of a tunnel. In this case there was minimal difference between a release from a 20 MPa natural gas system or a 20 MPa hydrogen system, however, a similar release from a 35 MPa hydrogen system was significantly more severe and particularly in terms of predicted overpressures. The present study has also highlighted that the ignition point significantly affects the combustion regime in confined environments. The results have indicated that critical cases in tunnels may tend towards a fast deflagration, or where there are turbulence generating features, e.g. multiple obstacles, there is the possibility that the combustion regime could progress to a detonation.
When comparing the urban and tunnel environments, a similar release of hydrogen is significantly more severe in a tunnel, and the energy available in the flammable cloud is greater and remains for a longer period in tunnels. When comparing hydrogen and natural gas releases, for the cases and environments investigated and within the limits of the assumptions, it appears that hydrogen requires different mitigation measures in order that the potential effects are similar to those of natural gas in case of an accident. With respect to a PRD opening strategy, hydrogen storage systems should be designed to avoid simultaneous opening of all PRD, and that for the consequences of the released energy to be mitigated, either the number of PRDs opening should be limited or their vents to atmosphere should be restricted (the latter point would require validation by a comprehensive risk assessment). 相似文献
To investigate the feasibility of using black carbon (BC) in the control of hydrophobic organic contaminants (HOCs) in sediment, we added BCs from various sources (rice straw charcoal (RC), fly ash (FC) and soot (SC)) to sediment to create different BC-inclusive sediments and studied the release of pentachlorophenol (PCP) in the sediments under different condition. Different pH values had no obvious effect on the release of PCP in BC-inclusive sediment, but solid/liquid ratio, temperature, salinity and dissolved organic matter (DOM) content had significant influences on the release of PCP in all sediments except the RC-inclusive sediment. Adding 2% RC to sediment resulted in a 90% decrease in PCP release, which was a greater decrease than observed with FC- and SC-inclusive sediments. Therefore, from the standpoint of HOC release, the application of RC is feasible for organic pollution control in the water environment. 相似文献
The basic function of the engineered barrier system (EBS) in geological disposal is to prevent or limit the release of radionuclides into the underground environment. For this purpose, the vitrified waste is contained in an overpack to isolate it from contact with groundwater for a certain initial period of time. However, it is impossible to ensure complete containment for all time. Therefore, the eventual release of nuclides must be minimized after the overpack fails (AEC, 1984. Radioactive waste processing and disposal measures; JNC, 2000a. Project to establish the scientific and technical basis for HLW disposal in Japan – first progress report-H3. Geological Environment in Japan, JNC TN1410 2000-002; JNC, 2000b. H12: project to establish the scientific and technical basis for HLW disposal in Japan – repository design and engineering technology, JNC TN1410 2000-003.). 相似文献
