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91.
Magdalena Svanstrm Morgan Frling Michael Modell William A. Peters Jefferson Tester 《Resources, Conservation and Recycling》2004,41(4):573
Environmental aspects of using supercritical water oxidation (SCWO) to treat sewage sludge were studied using a life cycle assessment (LCA) methodology. The system studied is the first commercial scale SCWO plant for sewage sludge in the world, treating sludge from the municipal wastewater treatment facility in Harlingen, TX, USA. The environmental impacts were evaluated using three specific environmental attributes: global warming potential (GWP), photo-oxidant creation potential (POCP) and resource depletion; as well as two single point indicators: EPS2000 and EcoIndicator99. The LCA results show that for the described process, gas-fired preheating of the sludge is the major contributor to environmental impacts, and emissions from generating electricity for pumping and for oxygen production are also important. Overall, SCWO processing of undigested sewage sludge is an environmentally attractive technology, particularly when heat is recovered from the process. Energy-conserving measures and recovery of excess oxygen from the SCWO process should be considered for improving the sustainability potential. 相似文献
92.
James F. Saunders Marylee Murphy Martyn Clark William M. Lewis 《Journal of the American Water Resources Association》2004,40(5):1339-1349
ABSTRACT: Historical flow records are used to estimate the regulatory low flows that serve a key function in setting discharge permit limits through the National Pollutant Discharge Elimination System, which provides a nationwide mechanism for protecting water quality. Use of historical records creates an implicit connection between water quality protection and climate variability. The longer the record, the more likely the low flow estimate will be based on a broad set of climate conditions, and thus provides adequate water quality protection in the future. Unfortunately, a long record often is not available at a specific location. This analysis examines the connection between climate variability and the variability of biologically based and hydrologically based low flow estimates at 176 sites from the Hydro‐Climatic Data Network, a collection of stream gages identified by the USGS as relatively free of anthropogenic influences. Results show that a record of 10 to 20 years is necessary for satisfactory estimates of regulatory low flows. Although it is possible to estimate a biologically based low flow from a record of less than 10 years, these estimates are highly uncertain and incorporate a bias that undermines water quality protection. 相似文献
93.
We draw on the economic, corporate governance, and family business literatures to explain why the effects of family on family firms makes this governance form theoretically distinct from those of public and private non‐family firms. Our thesis is that parental altruism, when combined with private ownership and owner‐management, influences the ability of the firm's owner‐manager to exercise self‐control, which, in turn, can expose some family firms to conflicts rooted in the agency threats of moral hazard, hold‐up, and adverse selection. We then discuss why some other family firms are able to minimize these dark side threats and thereby attain altruism's brighter side. Finally, we discuss how altruism's influence changes over time as ownership becomes dispersed among family members and across generations. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
94.
Aviva Savelson Robert Van Wynsberghe James Frankish Harmony Folz 《Local Environment》2005,10(6):629-647
The future of human health and that of all other species depends on the viability and sustainability of a host of environments and ecosystems. Human behaviours have profound effects (both positive and negative) on such ecosystems. Despite the obviousness of these statements, there remains a lack of clarity around the mechanisms for altering specific behaviours related to sustainability and their impact on environments. This paper offers a conceptual framework for identifying relations between human behaviour and ecosystem health and sustainability. We also discuss strategies for changing target behaviours in the context of a programme or policy planning. Finally, we draw on research that applies this adaptation to a small island community near Vancouver, Canada. 相似文献
95.
Quantifying and Evaluating Ecosystem Health: A Case Study from Moreton Bay, Australia 总被引:1,自引:0,他引:1
As part of the program monitoring the ecosystem health of Moreton Bay, Queensland, Australia, we developed a means for assessing
ecosystem health that allows quantitative evaluation and spatial representations of the assessments. The management objectives
for achieving ecosystem health were grouped into ecosystem objectives, water quality objectives, and human health objectives.
For the first two groups, aspects of the ecosystem (e.g., trophic status) were identified, and an indicator was chosen for
each aspect. Reference values for each indicator were derived from management objectives and compared with the mapped survey
values. Subregions for which the indicator statistic was equal to or better than the assigned reference value are referred
to as “compliant zones.” High-resolution surface maps were created from spatial predictions on a fine hexagonal grid for each
of the indicators. Eight reporting subregions were established based on the depth and predicted residence times of the water.
Within each reporting subregion, the proportion that was compliant was calculated. These results then were averaged to create
an integrated ecosystem health index. The ratings by a team of ecosystem experts and the calculated ecosystem health indices
had good correspondence, providing assurance that the approach was internally consistent, and that the management objectives
covered the relevant biologic issues for the region. This method of calculating and mapping ecosystem health, relating it
directly to management objectives, may have widespread applicability for ecosystem assessment. 相似文献
96.
97.
Alan?Rubelrstreiffer@wisc.edu" title="arubel@wisc.edu rstreiffer@wisc.edu" itemprop="email" data-track="click" data-track-action="Email author" data-track-label="">Email author Robert?Streiffer 《Journal of Agricultural and Environmental Ethics》2005,18(1):75-84
In her recent article, “Does autonomy count in favor of labeling genetically modified food?,” Kirsten Hansen argues that in Europe, voluntary negative labeling of non-GM foods respects consumer autonomy just as well as mandatory positive labeling of foods with GM content. She also argues that because negative labeling places labeling costs upon those consumers that want to know whether food is GM, negative labeling is better policy than positive labeling. In this paper, we argue that Hansen’s arguments are mistaken in several respects. Most importantly, she underestimates the demands of respecting autonomy and overestimates the cost of positive labeling. Moreover, she mistakenly implies that only a small minority of people desire information about GM content. We also explore the extent to which her arguments would apply to the US context, and argue that any discussion of the relationship between autonomy and labeling should include not just considerations of consumer autonomy but also considerations of what we call citizen autonomy. 相似文献
98.
Removal of selenate from water by zerovalent iron 总被引:1,自引:0,他引:1
Zerovalent iron (ZVI) has been widely used in the removal of environmental contaminants from water. In this study, ZVI was used to remove selenate [Se(VI)] at a level of 1000 microg L(-1) in the presence of varying concentrations of Cl-, SO(2-)4, NO(-)3, HCO(-)3, and PO(3-)4. Results showed that Se(VI) was rapidly removed during the corrosion of ZVI to iron oxyhydroxides (Fe(OH)). During the 16 h of the experiments, 100 and 56% of the added Se(VI) was removed in 10 mM Cl- and SO(2-)4 solutions under a closed contained system, respectively. Under an open condition, 100 and 93% of the added Se(VI) were removed in the Cl- and SO(2-)4 solutions, respectively. Analysis of Se species in ZVI-Fe(OH) revealed that selenite [Se(IV)] and nonextractable Se increased during the first 2 to 4 h of reaction, with a decrease of Se(VI) in the Cl- experiment and no detection of Se(VI) in the SO(2-)4 experiment. Two mechanisms can be attributed to the rapid removal of Se(VI) from the solutions. One is the reduction of Se(VI) to Se(IV), followed by rapid adsorption of Se(IV) to Fe(OH). The other is the adsorption of Se(VI) directly to Fe(OH), followed by its reduction to Se(IV). The results also show that there was little effect on Se(VI) removal in the presence of Cl- (5, 50, and 100 mM), NO(-)3 (1, 5, and 10 mM), SO(2-)4 (5 mM), HCO(-)3 (1 and 5 mM), or PO(3-)4 (1 mM) and only a slight effect in the presence of SO(2-)4 (50 and 100 mM), HCO(-)3 (10 mM), and PO(3-)4 (5 mM) during a 2-d experiment, whereas 10 mM PO(3-)4 significantly inhibited Se(VI) removal. This work suggests that ZVI may be an effective agent to remove Se from Se-contaminated agricultural drainage water. 相似文献
99.
William M. Adams Martin R. Perrow Angus Carpenter 《Journal of Environmental Planning and Management》2005,48(6):877-889
The restoration of river environments has been of growing importance to river management and planning in the UK. The extension of ecological restoration to floodplains as well as river channels is more complex, partly because of the range of stakeholders and the diversity of relevant management institutions. This paper draws on a qualitative survey of river managers in the UK to identify institutional factors relevant to the success or failure of floodplain restoration projects. 相似文献
100.