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ASIF QURESHI KWANG VICTOR LO DONALD S. MAVINIC PING HUANG LIAO FREDERICH KOCH HARLAN KELLY 《Journal of environmental science and health. Part. B》2013,48(7):1221-1235
A combined approach of biological treatment, solids digestion and nutrient recovery was tested on dairy manure. A sequencing batch reactor (SBR) was operated in three modes, in order to optimize nutrient (nitrogen and phosphorus) removals. The highest average removal efficiencies of 91% for NH4-N, 59% for PO4-P and 80% for total chemical oxygen demand (COD) were achieved. Staining experiments suggested the coexistence of glycogen and phosphorus accumulating organisms. Anaerobic digestion of wasted bio-solids was able to produce a PO4-P concentration of 70 mgL?1 in the supernatant. A pilot-scale experiment, designed to recover phosphorus in the supernatant as struvite (magnesium ammonium phosphate), was able to remove 82% of soluble PO4-P. 相似文献
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/ A study was conducted to determine the extent of nitrogenpollution in agricultural lands in the Lower Fraser River basin of BritishColumbia, Canada. The specific objectives were to determine the distributionof leachable nitrogenand estimate the nitrogen concentration in groundwaterrecharges. Nitrogen and water mass balances were conducted on the entirebasin and on each of the four districts comprising it over the period1971-1991 in intervals of five years. The results indicated that the averagenitrogen concentration in the groundwater recharge for the entire basin rosefrom nondetectable in 1971 to 6 mg/liter in 1991. Estimates for theindividual districts ranged from 4 to 14 mg/liter in Central Fraser and fromnondetectable to 7 mg/liter in Fraser-Cheam and 3 mg/liter in both GreaterVancouver and Dewdney-Alouette. So far, excessive levels of nitrogen areconfined to Central Fraser. Although they have remained within the acceptablerange, nitrogen concentrations in the other three districts have definitelyincreased over the 20-year study period. Sensitivity analyses indicated thatanimal manure and fertilizer had the largest contribution in groundwaterrecharge. Decreasing the rate of manure application to agricultural lands issuggested as the most practical way of reducing nitrogen pollution in CentralFraser.KEY WORDS: Nitrogen balance; Water balance; Sensitivity analysis 相似文献
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Preventing groundwater contamination is vastly cheaper than remediation. Recognizing this, attention in water and land management
agencies in North America increasingly turn to groundwater protection. Local agencies, such as municipalities and watershed
management districts, are vital to successful groundwater protection, but they face daunting challenges. In the United States,
senior governments have recognized these challenges and provide considerable support for local agencies. In Ontario, Canada,
local agencies are, to a much greater extent, on their own. The aims in this paper are to analyze factors that shape local
capacity for groundwater protection, focusing on Ontario, and to recommend avenues for capacity building. Interrelationships
among five dimensions of capacity (technical, financial, institutional, social, and political) are explored through an analysis
of three smaller Ontario communities: City of Guelph (population 93,400), Town of Orangeville (population 22,188), and Town
of Erin (population 11,000). Size clearly influences capacity for groundwater protection. However, other considerations unrelated
to size appear to be as important. These other factors include the ability to form horizontal and vertical linkages with external
agencies, political leadership and commitment, and citizen involvement. Thus, smaller communities in Ontario (and other jurisdictions
with limited senior government support) would do well to focus on these areas at the same time as they develop their technical,
financial, and institutional capacity. 相似文献
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Serveiss VB 《Environmental management》2002,29(2):145-154
Considerable progress in addressing point source (end of pipe) pollution problems has been made, but it is now recognized
that further substantial environmental improvements depend on controlling nonpoint source pollution. A watershed approach
is being used more frequently to address these problems because traditional regulatory approaches do not focus on nonpoint
sources. The watershed approach is organized around the guiding principles of partnerships, geographic focus, and management
based on sound science and data. This helps to focus efforts on the highest priority problems within hydrologically-defined
geographic areas. Ecological risk assessment is a process to collect, organize, analyze, and present scientific information
to improve decision making. The U.S. Environmental Protection Agency (EPA) sponsored three watershed assessments and found
that integrating the watershed approach with ecological risk assessment increases the use of environmental monitoring and
assessment data in decision making. This paper describes the basics of the watershed approach, the ecological risk assessment
process, and how these two frameworks can be integrated. The three major principles of watershed ecological risk assessment
found to be most useful for increasing the use of science in decision making are (1) using assessment endpoints and conceptual
models, (2) holding regular interactions between scientists and managers, and (3) developing a focus for multiple stressor
analysis. Examples are provided illustrating how these principles were implemented in these assessments. 相似文献
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SZU-HUA PAN KWANG VICTOR LO PING HUANG LIAO HANS SCHREIER 《Journal of environmental science and health. Part. B》2013,48(4):451-458
Both the advanced oxidation process (AOP) using a combination of hydrogen peroxide addition and microwave heating (H2O2/microwave), and the microwave heating process were used for solubilization of phosphorus from liquid dairy manure. About 80% of total phosphate was released into the solution at a microwave heating time of 5 min at 170°C. With an addition of H2O2, more than 81% of total phosphate could be released over a reaction period of 49 h at ambient temperature. The AOP process could achieve up to 85% of total phosphate release at 120°C. The results indicated that both the microwave, and the AOP processes could effectively release phosphate from liquid dairy manure. These processes could serve as pretreatments for phosphorus recovery from animal wastes, and could be combined with the struvite crystallization process to provide a new approach in treating animal wastes. 相似文献
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Klemas VV 《Environmental management》2001,27(1):47-57
Advances in technology and decreases in cost are making remote sensing (RS) and geographic information systems (GIS) practical and attractive for use in coastal resource management. They are also allowing researchers and managers to take a broader view of ecological patterns and processes. Landscape-level environmental indicators that can be detected by Landsat Thematic Mapper (TM) and other remote sensors are available to provide quantitative estimates of coastal and estuarine habitat conditions and trends. Such indicators include watershed land cover, riparian buffers, shoreline and wetland changes, among others. With the launch of Landsat 7, the cost of TM imagery has dropped by nearly a factor of 10, decreasing the cost of monitoring large coastal areas and estuaries. New satellites, carrying sensors with much finer spatial (1-5 m) and spectral (200 narrow bands) resolutions are being launched, providing a capability to more accurately detect changes in coastal habitat and wetland health. Advances in the application of GIS help incorporate ancillary data layers to improve the accuracy of satellite land-cover classification. When these techniques for generating, organizing, storing, and analyzing spatial information are combined with mathematical models, coastal planners and managers have a means for assessing the impacts of alternative management practices. 相似文献
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