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121.
122.
123.
Tom Van Remmen 《Waste management (New York, N.Y.)》1998,18(6-8)
After many years of research and debate, in August of 1997 the United States Environmental Protection Agency (EPA) issued New Source Performance Standards (NSPS) and Emission Guidelines (EG) for medical/infectious waste incinerators in the United States. These new emissions and operational standards establish considerably more restrictive limitations on air emissions for medical/infectious waste incinerators and will undoubtedly have a significant impact on the over 2300 hospitals presently operating an incinerator on-site. This paper will explore the options available to these facilities, and those facilities which may be considering installation of an incinerator, relative to achieving compliance with the NSPS and EG for medical/infectious waste incinerators. 相似文献
124.
In 1991, provisions for environmental impact assessment in New Zealand were changed significantly with the enactment of the
Resource Management Act. Among other provisions, this act requires consideration of cumulative impacts in environmental assessment
activities undertaken by planners in newly created regional authorities and district and city councils. The institutional
context in which the act is being implemented offers both opportunities and constraints to cumulative impact assessment. A
lack of methods for CIA is a recognized problem. However, methods that have been developed for environmental impact assessments
can be modified to incorporate second-, third-, and fourth-order impacts as well as to identify the direction and magnitude
of additive and synergistic impacts. Layered matrices and combined networks are examples of such methods. While they do not
allow for scientific prediction, they do provide the practitioner with the ability to consider the cumulative impacts of decisions.
This is crucial in New Zealand, where statutory requirements are ahead of established methodologies. 相似文献
125.
介绍了喷射钻井井底流场特性、喷嘴射流破岩机理、脉冲射流喷嘴、新型水力流道钻头的研究与应用情况,以及水射流技术在石油钻井用钻头上的应用前景。 相似文献
126.
S. Lawrence. Dingman Diana M Seely-Reynolds Robert C. Reynolds 《Journal of the American Water Resources Association》1988,24(2):329-339
ABSTRACT: Estimates of mean annual precipitation (MAP) over areas are the starting point for all computations of water and chemical balances for drainage basins and surface water bodies. Any errors in the estimates of MAP are propagated through the balance computations. These errors can be due to: (1) failures of individual gages to collect the amount of precpitation that actually falls; (2) operator errors; and (3) failure of the raingage network to adequately sample the region of interest. This paper attempts to evaluate the last of these types of error by applying kriging in two different approaches to estimating MAP in New Hampshire and Vermont, USA. The data base is the 1951–1980 normal precipitation at 120 raingages in the two states and in adjacent portions of bordering states and provinces. In the first approach, kriging is applied directly to the MAP values, while in the second, kriging is applied to a “precipitation delivery factor” that represents the MAP with the orographic effect removed. The first approach gives slightly better kriged estimates of MAP at seven validation stations that were not included in the original analysis, but results in an error surface that is highly contorted and in larger maximum errors over most of the region. The second approach had a considerably smoother error surface and, thus, is generally preferable as a basis for point and areal estimates of MAP. MAP estimates in the region have 95 percent confidence intervals of about 20 cm/yr at low and moderate elevations, and up to 35 cm/yr at high elevations. These uncertainties amount to about 20 percent of estimated MAP values. 相似文献
127.
MULTI-MEDIA CONCENTRATIONS OF HEAVY METALS AND MAJOR IONS FROM URBAN AND RURAL SITES IN NEW BRUNSWICK, CANADA 总被引:1,自引:0,他引:1
Concentrations of heavy metals and major ions were measured in precipitation, snowpack, garden soils and vegetables from urban and rural sites in New Brunswick in Atlantic Canada. Atmospheric loading of mercury, lead, cadmium, arsenic, strontium, and vanadium need further assessment. Vanadium concentrations in precipitation, snowpack, soils and vegetables showed an urban influence. Vanadium concentrations in the snowpack ranged between <2.0 ppb at 50 kilometers from the city center to 31.4 ppb in the city. Concentrations of all heavy metals in urban soils were less than CCME remediation guidelines but selected metals exceeded the assessment benchmark non-regulatory guidelines. Major ions were consistently higher in event precipitation than the snowpack. The order of ion elution from the snowpack was NO3 > SO4 > NH4 > H > Mg > Cl > Na > K. Hydrogen ion equivalents were highest in the snowpack and precipitation from urban samples. Mean hydrogen ion concentrations ranged from 11 to 22 eq L-1 in the snowpack compared with 18 to 41 eq L-1 in event precipitation. 相似文献
128.
The distribution of trace metals in sediments of the lower reaches of the New Calabar River, Nigeria was evaluated togetherwith the partitioning of their chemical species between fivegeochemical phases. Samplings were made in five zones at the lower reaches of the New Calaber River. All the trace metals were determined by AAS after selective chemical extractions andconcentrations given in g gm-1 (dry weight basis). The average totalconcentrations found for trace metals in the sediment were (mean ± rsd.) Pb: 41.6 ± 0.29, Zn: 31.60 ± 0.42, Cd: 12.80 ± 0.92, Co: 92 ± 0.25, Cu: 25.5 ± 0.65 and Ni: 3.2 ± 0.25. Maxima and minima concentrations are inconsistent with previous studies in other rivers of this region. Spatial distribution revealed that the sources of trace metals into theriver appeared to be of non-point. Five contamination indices were applied in studying the partitioning of the trace metals inthe sediment. These indices provided bases for ascertaining the potential environmental risk of trace metals in the river system.The results denote high partition levels in the more mobile andmore dangerous phases. 相似文献
129.
新型厌氧反应器处理生活污水的研究进展 总被引:4,自引:0,他引:4
新型高速厌氧反应器的发生使生活污水的厌氧处理成功可能,介绍了几种厌氧反应器的特点及其在生活污水处理中的研究现状。 相似文献
130.
We developed logistic regression models from data on biotic and abiotic variables for 172 sites on Banks Peninsula, New Zealand,
to predict the probability of occurrence of two diadromous fish, banded kokopu (Galaxias fasciatus) and koaro (G. brevipinnis). Banded kokopu occurrence was positively associated with small streams and low-intensity land uses (e.g., sheep grazing
or forested), whereas intensive land uses (e.g., mixed sheep and cattle farming) and lack of riparian forest cover impacted
negatively on occurrence at sampled sites. Also, if forests were positioned predominantly in lowland areas, banded kokopu
occurrence declined with increasing distance to stream mouth. Koaro occurrence was positively influenced by catchment forest
cover, high stream altitudes, and areas of no farming activity or mixed land uses. Intensive land uses, distance to stream
mouth, and presence of banded kokopu negatively influenced koaro occupancy of stream reaches. Banded kokopu and koaro presence
was predicted in 86.0% and 83.7% agreement, respectively, with field observations. We used the models to quantify the amount
of stream reaches that would be of good, moderate, and poor quality, based on the probability of occurrences of the fish being
greater than 0.75, between 0.75 and 0.5, or less than 0.5, respectively. Hindcasting using historical data on vegetation cover
undertaken for one catchment, Pigeon Bay, showed they would have occupied most of the waterway before anthropogenic modification.
We also modeled potential future scenarios to project potential fish distribution. 相似文献