This research was developed as one of the first studies to investigate riverine litter problems. Baseline assessment methods were formulated to define the scope and nature of this pollution form. Assessments were carried out in three catchments; the Taff East Lyn and Avill. The Taffwas found to be atypical regarding the extent of the litter. In all catchments plastic sheeting formed the principal litter component. The study also included an examination of the factors influencing the sources, pathways and sinks riverine litter pollution. These factors were drawn together through the development of a research model. Assessments of two quantifiable sources, sewage inputs through Storm Water Overflows (SWOs) and fly-tipping wastes, were undertaken. Greatest inputs of sewage-derived solids were introduced to the river through malfunctioning SWOs, the most numerous single component being sanitary towels. Whilst sewage-derived material constituted approximately 23% of all items on the River Taff large quantities of waste, especially plastic sheeting, originated from fly-tipping sites. Mobility of litter once introduced to the system was greatly dependent on river flow regimes. Some litter types, e.g. plastic sheeting, were more mobile than others and tended, after floods, to be stranded on vegetation. Due to its high profile within the catchments and expected longevity, plastic sheeting was chosen for river-bank degradation trials. Results indicated that photodegradation occurred within samples, but only in the initial exposure period and that any further breakdown was likely to result from physical abrasion. Marine areas were considered to be potential sinks for riverine litter, especially its more mobile components. An alternative sink for certain litter types such as cloth might be incorporation into the river-bank due to an ability to aggregate soil/sediment particles.

This study set out to investigate the processes that lead to emitter fouling in wastewater reuse systems. The susceptibilities of several emitter designs to clogging were compared and the role of phytoplankton in the clogging process and in the development of algal mats was investigated. Emitter design was found to be an important factor controlling the degree of clogging. Those designs that operated most efficiently used a long-path narrow labyrinth to control emitter output and encourage turbulent flow. Simpler designs that controlled flow by small sponge inserts or by stitched tubing were found to be unsuitable for use with treated wastewaters. The most common cause of clogging was found to be sand particles in the size range 360 urn to 1080 urn, trapped within the narrow channels of emitters. The sand contaminated the entire irrigation system from the potable water supply in July 1987, before a screen filter was installed in the water supply line. Emitter clogging under these circumstances was a problem, to varying degrees, for all emitter designs and for all water qualities. Emitters supplied with WSP effluent generally clogged to a greater degree than those supplied with potable water and the principal cause of clogging was shown to be sand particles. However, no statistically significant difference was recorded in the discharge characteristics of the most efficient emitter design between different water qualities. Thorough cleaning of the irrigation laterals in 1987 and replacement of emitters in 1988 failed to eradicate the sand contamination problem. Examination of clogged emitters by electron microscopy showed that organic material encased the sand particles in clogged emitters from laterals supplied with WSP effluent, thereby sealing the water channel. This mass was shown to be comprised of dead microalgae and invertebrate animals such as Daphnia spp. on which bacteria developed. Microalgae did not multiply in the dark environment of the emitter interiors. External algal mats were detected on less than 5 percent all emitters supplied with WSP effluent and were absent on all emitters supplied with potable water. Emitter C, which was the design that presented the largest wetted surface to sunlight, developed the greatest number of mats and covering these emitters with black polythene prevented mat development. The mats were shown to comprise of predominantly filamentous cyanobacteria (Oscil/atoria spp. and Lyngbya spp.) and filamentous green algae (Microcystis spp.). Although these organisms were also detected on the walls of the maturation pond, they were not detected in grab samples of pond effluent which contained predominantly planktonic algal genera such as Euglena spp. and Chlorella spp. Short decaying filaments of Oscillatoria spp. were, however, detected within the irrigation laterals and on the surfaces of sand particles within clogged emitters and no degree of filtration would guarantee their complete removal from the pond effluent. It was hypothesised that their development on the outer surfaces of emitters was a result of colonization of a well-illuminated, wet and nutrient-rich environment and that the source of the inoculum was as likely to be the soil as to be the maturation pond. Studies of greenhouse irrigation systems in the UK revealed that algal mats were a consequence of applying inorganic nutrients to the crop in the irrigation water: their development can be prevented in greenhouses by chlorination of the water supply. It was concluded that clogging results from a combination of physical, chemical and biological factors. Sand particles can be efficiently removed from the water supply by incorporating a simple screen filter, with a mesh size of at least 120, that allows microalgae to pass through the system to the soil. Clogging by sand particles was exacerbated by chemical precipitation of calcium carbonate and by the development of a organic material over the surface of the sand particles in emitters supplied with pond effluent. Biological growth alone was not shown to cause emitter clogging. It was also shown that the development of algal mats over the outer surface of emitters supplied with pond effluent were not a result of an accumulation of pond algae at this point but represented an opportunistic colonization of a well illuminated nutrient-rich environment by microorganisms from the atmosphere and/or soil. Algal mats had no adverse effect on the operation of emitters in WSP reuse irrigation.

The Redwater Production Area (RPA) is an established oil field located north of Edmonton in central Alberta. Recent assessments indicate that substantial amounts of hydrocarbon contaminated soil exist in the RPA as a result of the use of flare pits, ecological ponds, product spills and pipeline leaks. Alternative remedial technologies may reduce the quantity, cost, and ultimately the long-term liabilities associated with the current practice of landfill disposal. The purpose of this thesis is to assess the viability of accelerated biopile soil treatment as a remedial methodology in the rehabilitation of contaminated soil in the RPA. The thesis includes a literature search, a bench scale treatability and pilot biopile experiment and concludes with a summary of the viability of biopiling to be employed as part of a multi-year/multi-site remedial initiative. Construction of the Redwater Soil Treatment Facility began in 2008 with treatment and recycling operations commencing in early 2009.

A laboratory study was conducted to bioremediate a fine textured soil contaminated with diesel. The local microorganisms were stimulated by supplying nutrients with the aid of a water table management system. A fine textured soil, contaminated for more than 20 years, with more than 6500 mg/kg of diesel was packed in fifteen columns, 2 m long and 0.2 m in diameter. Twelve out of fifteen soil columns were subjected to bioremediaton, by supplying nutrients, water and air at desired depths. Three columns were used as a control to monitor passive degradation of contaminant without intervention. / The experiment was designed to employ three different treatments in triplicates. In the first treatment, nutrients, air and water were supplied. In the second, only nutrients and water were applied and in the third, water alone was applied. These treatments were applied by two different water table management strategies. In the first, three columns were remediated by following a full column remediation strategy, while in the second, nine columns were treated in a stagewise manner, by maintaining the water table at 1 m depth from surface. (Abstract shortened by UMI.)

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