Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 16 of 16 for “"Diffuse sources"”.
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Phosphorus transport in the Berg River, Western Cape
… consider (1) export of phosphorus from nonpoint (diffuse) sources via surface and subsurface drainage, and from point sources such as wastewater treatment discharges, (2) transportation of phosphorus in the water prism along the river channel, taking account of removal and remobilization of …
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Waste discharge charge system : the practical implication from a gold mining perspective
… role players in managing South Africa's water resources. Water resources are under increasing pressure due to continuous population growth and economic development. It is critical to adopt a management policy that can lead to sustainable water supply. The National Water Act, 1998, (Act 36 of …
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The phosphorus transfer continuum under climate change
… as a critical example of how anthropogenic point sources of P can alter the retention of P even at the headwater scale where agricultural diffuse sources dominate. I use bi-weekly sampling of P, chloride (Cl- ) and flow (Q), load apportionment modelling (LAM) and mass balance, alongside sediment …
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An investigation towards passive treatment solutions for the oxidation of sulphide and subsequent removal of sulphur from acid mine water
… for the treatment of smaller discharges from diffuse sources, such as coal spoil heaps, overburden and waste rock dumps, over a long period of time. In addition, they are questionable from a sustainability perspective. The Integrated managed passive (IMPI) treatment system is a semi-passive …
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Environmental risk assessment of heavy metals in urban street dust
… been paid to widely spread and un-regulated diffuse sources in the urban environment. This thesis employs several practical approaches (chemical, biological, kinetics) together with a theoretical model to assess the potential risk of diffuse sources of cadmium, copper, lead and zinc in urban …
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Modeling Farm-Level Costs of the Yield Reserve Program
… (NPS) pollution, pollution that comes from diffuse sources that are difficult to trace back to a single point such as farm fields, is a major concern affecting America's water ways. Nationally, agriculture is the leading source of water impairment and has also been identified as the largest …
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Observations and implications of sediment-water interactions in the Niagara impoundment of southwest Virginia
… effectiveness of upstream control of point and diffuse sources.
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Constructed treatment wetlands: Tools to attenuate diffuse agricultural pollution and enhance the biodiversity of eutrophic peat lake ecosystems
… municipal, industrial and agricultural point sources. Further, CTWs are becoming increasingly prevalent as mitigation tools to manage diffuse pollution from agricultural runoff. However, discrepancies among studies of the performance of CTWs treating diffuse sources of N, P and SS have created …
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Factors influencing phosphorus losses in agroecosystems dominated by tile drainage
… but phosphorus surpluses may be conveyed from diffuse sources to streams via surface runoff and artificial subsurface (perforated plastic pipes called tiles) drainage affecting the quality of receiving aquatic ecosystems. However, controls of phosphorus losses at the sub-field and watershed …
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Toxicology of endocrine disrupting chemicals
… chemicals, natural hormones and phytoestrogens. Sources of exposure include point sources from industries and homes, and diffuse sources from agricultural farm lands and vehicles. Humans or wildlife can be exposed to EDCs through major pathways such as air, water, food and soil. 4 The behavior …
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Integrated modelling of Global Change impacts in the German Elbe River Basin
… Even though nutrient emissions from point sources have notably decreased in the basin due to reduction of industrial sources and introduction of new and improved sewage treatment facilities, the diffuse sources of pollution are still not sufficiently controlled. The investigations have been …
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Phosphorus fate and management on the Somerset Levels and Moors Ramsar ditch systems
… point (e.g., wastewater treatment works) and diffuse (largely agricultural runoff) sources, is currently the central reason for failure in the majority of surface water bodies in England to meet required water quality guidelines. Historic data indicate that surface waters within the ditch …
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A novel semi-passive process for sulphate removal and elemental sulphur recovery centred on a hybrid linear flow channel reactor
… management of the country's existing water resources to ensure sustainable water security. In SA, the primary focus on remediation of ARDcontaminated water has been based on established active technologies. However, these approaches are costly, lead to secondary challenges and are not always …
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Optimisation of a linear flow channel reactor for semi-passive, simultaneous biological sulphate reduction and partial sulphide oxidation
… rebound, and those that are generated from diffuse sources, as low-flow ARD. Low-flow ARD and neutral rock drainage are amenable to biological treatment of the sulphate component using sulphate reducing bacteria (SRB). Biological sulphate reduction (BSR) generates sulphide, which requires …
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Integrated watershed modeling of mountainous landscapes : Assessing the environmental performance of an intensive farming system in South Korea
… Nonpoint source pollutions come from many diffuse sources (surface runoff, atmospheric deposition, precipitation, and seepage) and are more difficult to handle compared to point source pollution. The extent of generation of nonpoint source pollution depends on complex geophysical and …
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A Comparative Analysis of the Performance and the Microbial Ecology of Biological Sulphate Reducing Reactor Systems
… ARD lies solely with government. Although these diffuse sites often generate smaller volumes of less aggressive ARD compared to that generated through mine water rebound, the sheer number and the continual ARD generation from these sites is a severe threat to South Africa's already poor water …