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A programme of research has been carried out into the performance of cartridge filters rated from 0.1 to 0.45 micron in response to steady and varying particle concentrations and water flows. It was discovered that pulsing the water flow to these filters often resulted in release of particles which had been previously captured by the filter. For membrane filters the release of particles was instantaneous. However, for one filter with more depth, a considerable time was required for most of the particles released to be detected. This filter was described as a pre-filter rather than a membrane filter.

Wood debris has been a natural component of the Fraser River system for centuries. However, with the development and expansion of a diverse forest industry in British Columbia, the volume of waterborne logging wastes being discarded into the river has gradually increased to the point where logging slash, uncontrolled sawlogs, trimmed log ends and dislodged bark now present a serious problem to the users of the Lower Fraser and its shorelands. Where water pollution can be defined as any residual discharge into a watercourse which causes both a deterioration in the quality of the receiving waters and some form of related social costs, sawlogs and other types of wood debris present a rather unique example of a pollutant to the Lower Fraser River. From this perspective, the available literature on pollution control provides an appropriate methodology for defining and analyzing the issues and problems associated with the presence of this material in the waterway. In 1972, uncontrolled sawlogs accounted for 9.2 million cubic feet of wood debris or roughly 80 per cent of the total debris load in the river. These logs were responsible for approximately 4.5 million dollars in costs to fishermen, pleasure boat owners, harbour authorities, and private logging companies. While it is realized that there are substantial additional costs related to the environmental impacts of sawlog debris, more studies are needed to determine the significance of these impacts on / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate

Pesticides are a growing concern around the world as they are widely increasing in use and not as highly regulated as some health and environmental hazards. As agricultural, home, and other pesticide applications continue to rise, the need for analytical testing and removal of these pesticides from our rivers, streams, and other runoffs is becoming more and more significant. Glyphosate, an active ingredient in the herbicide Roundup, is an amine compound that has a maximum contamination level of 700 ppb. This work studied the use of water soluble Iron (II) tetrasolfophthalocyanine in amine detection that could be further applied to glyphosate. Also included in this study is a glimpse of removal possibilities combining phthalocyanines with traditional adsorption media for enhanced extraction and capacity.

The term water clarifier as used in this text refers to a versatile water treatment unit which combines flocculation and coagulation, clarification and positive sludge removal in a single tank. Water clarifiers are very compact units which are being used in municipal and industrial water treatment for the removal of turbidity, algae, color, iron and silica; lime or lime-soda softening; magnesium precipitation; brine clarification; and waste water clarification with or without chemicals. Water clarifier units have found wide use in the sanitary field, providing high removals in the pre-treatment of sewage and in secondary sewage treatment through addition of coagulants.

This dissertation brings together the history of slavery and environmental history to explore the legacy of slavery on Texas’ Trinity River from the 1820s to the 1970s. Many southern rivers, including the Trinity, experienced few sustained efforts to transform or control them until well into the twentieth century, and these environments were just as likely to diffuse rather than consolidate any particular group’s power over people. Unlike elites in the older regions of the slave South, no one assumed that they controlled the environment in places such as Texas’s Trinity River. Drawing on nearly fifty different archives, my dissertation explains the surprising ways in which slavery, urbanization, and environmentalism were connected. Environmental racism changed the Trinity into a more flood prone and polluted place, but it also meant that its mostly black residents were rarely mentioned in official engineering reports or newspaper articles. This invisibility served as a temporary advantage during the racist violence of the post-emancipation decades and people squatted on land for which they did not hold titles. However, because so many people were not included in official records such as census reports, I have relied on qualitative sources to analyze this history. Freedpeople incurred plantation slavery’s environmental debts of erosion and disease, but they also seized the opportunity to avoid crop-liens and other forms of usury by living in an overlooked landscape. Upstream cities on the Trinity gave little consideration to the effects of using the river as a sewer, and they ignored the black families who called the river home. In the early twentieth century, a novel class of elites on the lower half of the river began to issue bonds to build levees that pushed out many longtime residents. As prisons replaced plantations and subsistence-oriented farmers could no longer endure the worsened floods, pollution, and enclosure of its common lands, the lower Trinity lost most of its remaining residents. Yet as debates raged along the entire river about remaking it into a canal and the proper use of state and federal resources, the memory of an unruly river contributed to the political outcomes despite slavery’s legacy of inequality.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science in hydrogeology, School of Geosciences. Johannesburg, 23 May 2016. / Groundwater treatment by chemical precipitation is a popular form of remediation at mines that are in operation. The water quality status at the implementation of the PAT in this study was compared to the water quality status after a six-month period of active remediation. Chromium is very important as an industrial metal owing to its numerous uses in a variety of industries. The objective of the remedial action is to intercept the Cr(VI) plume, abstract contaminated groundwater and chemically treat it on the surface. The long-term (15-year) objective is to eventually reduce Cr(VI) concentrations in the aquifer(s) to below 0.05 mg/ℓ. The PAT system was implemented as a mediumterm (5-year) strategy to intercept the Cr(VI) contamination plume during migration to prevent it from negatively impacting on groundwater users downstream of the mine. In the vicinity of the three PAT systems’ abstracting wells, water levels declined by an average of 2 m compared to the same period in 2014. Periodical fluctuations in the fractured aquifer are reflective of the influence of fractures on groundwater flow. In the aquifer, hydrochemical signatures show evidence of mixing between the primary and secondary aquifers. The treatment system has been successful in reducing Cr(VI) to Cr(III) and precipitating Cr(OH)3. The treatment system was designed to treat Cr(VI), other elevated constituents and generally high dissolved ions are not treated in this remedial process. Sulphate concentrations increase after treatment as a result of the addition of Fe(II)SO4 for chromate contamination treatment purposes. The simulated reaction path shows that the transformation of CrO4 2- to Cr2O3 in the treatment system is not immediate. The Cr(VI) to Cr(III) transformation is irreversible, this is beneficial as the water is abstracted from more reducing conditions, and the treatment ponds are open to the atmosphere thus the conditions following dosing with Fe(II)SO4 are oxic and chromate complexes are stable over a wider range of Eh-pH conditions than Cr(III) compounds. This ensures that the efficiency of the dosing system is not reversed in Settling Pond B. The modelled flow paths are similar to the inferred flow vectors in the plume capture zone. Fracture flow is the dominant type of flow, the fault zones and dykes create high permeability conduits to flow. Flow paths are parallel to fault lines or the lateral dimension of dykes; flow occurs along fractures and deformation zones. The reduction of Cr(VI) concentrations in some of the peripheral sampling points indicates that the PAT system has been successful in capturing the chromate contaminated water through pumping. Keywords: Hexavalent chromium, groundwater pollution, remediation, pump-and-treat, fractured aquifers / GR2016