Human uses and abuses of rivers have grown and diversified over the last few centuries with increasing urban development. With increasing population growth, there has been increasing demand for the use of rivers to satisfy a diverse range of human needs including solid waste disposal and the discharge of industrial, sewage and mining effluents. Rivers have been abstracted for agricultural and potable water supply and river channels have been modified for navigation, flood defences and hydro-electric power generation. These modifications to the river system disrupt the fabric of the aquatic ecosystem and diminish its integrity, affecting equally the capacity of fish and other organisms to survive. Fish depend on undamaged interactive pathways to enhance their survival, growth and recruitment.The Don, Rother and Dearne catchment in South Yorkshire and North East Derbyshire has suffered from a legacy of pollution and land contamination that dates back to the Industrial Revolution. These rivers have been grossly polluted from industrial, sewage, and mining effluents and from the disposal of solid wastes in the catchment. Much of the lengths of these rivers were fishless into the mid 1980s.Fish populations in the catchment remain low and species diversity is poor at most locations in the Don sub-catchment. Brown trout and coarse fish species are present in the Don catchment, with the salmonid populations confined to the upper reaches. Most tributaries of the River Don provide brown trout recruits to the main rivers but poor water quality and degraded habitats have prevented the successful colonisation of the waters by the species. Coarse fish, where present, were found at the middle and lower reaches of the river.Fish populations and species diversity in the River Dearne are generally poor due to serious water quality problems. Limited numbers of brown trout and coarse fish were found at few locations in the catchment, reflecting the widespread nature of poor water and habitat quality. The sub-catchment receives diverse discharges from sewage, industry and abandoned mines. This is exacerbated by various pollution incidents, the causes of some of which remain unidentified.The River Rother has low fish population densities, and many stretches of the river are fishless due mainly to poor water quality and lack of suitable habitats. Some tributaries of the River Rother, particularly the River Hipper, Redleadmill Brook and Brookside Beck hold considerable numbers of brown trout. The Rother sub-catchment also receives sewage, industrial and mine effluents which impact on the water quality.The benthic macroinvertebrate fauna of the sites studied were mainly pollution-tolerant taxa with low species diversity reflecting poor water quality. Heavy metal levels were generally low and declining which, possibly, relate to the decline in steel and coal industry in the catchment.A concerted programme to improve effluent discharges from major sewage treatment works and industries serving the catchment area coupled with a decline in the coal, steel and manufacturing industries has resulted in marked improvements in water quality of the rivers. Reductions in ammonia and BOD levels have been achieved since 1991 due mainly to improvements to sewage treatment works. As a consequence the fisheries of the rivers have shown some evidence of recovery. Unfortunately these improvements are localised and the fish populations suffer periodic setbacks because of isolated pollution incidents.Despite considerable efforts by the Environment Agency and its predecessors (the National Rivers Authority and Yorkshire Water), to improve the fish populations through stocking and some habitat improvement measures, the general status of the fisheries remains poor particularly in the Rivers Dearne and Rother. A strategic Aquatic Resources Management Plan (ARMP) targeting the bottlenecks to recovery and improvement in the water quality and fisheries habitat is proposed for the long-term sustainable improvement of the fisheries. Project Concept Notes and Logical Project Frameworks have been developed to address the water quality, habitat and fisheries rehabilitation problem. These constitute draft proposals for which additional information would be needed before projects can be progressed.

This study provides an assessment of the fish assemblage of the Humber estuary, using a quarterly sampling interval. Sampling 14 subtidal stations throughout the estuary, and two intertidal sites in the outer estuary, the principal aims of the study were to determine the structure and functioning of the assemblage and the environmental and biological factors influencing the fish distribution.

The conventional approach to water quality monitoring is to combine periodic sampling with batch analysis in the laboratory. Such a procedure is both labour intensive and time consuming, there are likely to be sample stability and contamination problems, and the information provided is unlikely to be continuous or immediate. This research focussed on the design and construction of fully automated and portable monitors based on flow injection analysis and incorporating solid state photometric detectors. A novel solid state photometric detector was constructed, incorporating light emitting diodes as the light source, which could be used in conjunction with flow injection analysis. Manifolds were studied for a range of species of interest (phosphate, nitrate, ammonia and aluminium) in the field of water quality monitoring and were optimised for their suitability for continuous use. An automated monitor for nitrate was constructed and long term evaluation trials were carried out at several locations for water quality monitoring. Results are also presented for the use of a nitrate monitor in hydroponic cultivation. An automated monitor was also built for the monitoring of ammonia levels in natural waters, which was field tested on the River Avon (Wiltshire). A manifold was also evaluated for the monitoring of residual aluminium levels in drinking water and is currently being commissioned at a water treatment works in Somerset.

Thesis (LL. M.)--University of Toronto, 2004. / Adviser: Michael Trebilcock.

Thesis (M.S. - Soil, Water and Environmental Science)--University of Arizona, 1997. / Includes bibliographical references (leaves 43-48).

Thesis (M. Sc.)--University of Hong Kong, 1996. / Includes bibliographical references.

The overall aim of this research was to contribute to the optimisation of aerobic wastewater treatment processes in sequencing batch reactors, by investigating the performance of the process with real and model wastewaters in order to achieve the highest possible reduction of influent COD with the minimum reactor volume and oxygen consumption. Six industrial wastewaters from the food and drink companies were treated in lab-scale aerobic sequencing batch reactors (SBRs) inoculated with soil and monitored for COD and total suspended solids (TSS) removal. The results showed high COD removal efficiencies for all the wastewaters, in the range of 64-95 %. Extended aeration tests were carried out on the reactor effluents and the results indicated that the residual soluble COD was not further biodegradable. This indicates that the soluble BOD removal in the reactors was virtually 100 %. The biodegradation efficiency was investigated over two values of the solids retention time (SRT) and the performance of the reactors was essentially unaffected by the SRT (in the range of 7-18 days considered in this study). This means that very good COD removal can be achieved at relatively lower SRT, with potential savings in capital and operating costs. The removal of TSS for the wastewaters was not satisfactory, largely due to the low food to microorganism (F/M) ratios (0.13-0.29 kg COD/kg biomass.day) in the reactors. Three batch tests at different initial substrate to biomass (So/Xo) ratios were carried out on each of the two industrial wastewaters for kinetic characterisation of the wastewaters. Oxygen uptake rate (OUR) was measured during the tests and the OUR profiles were used for the estimation of the kinetic parameters using a mathematical model consisting of substrate hydrolysis, biomass growth and endogenous metabolism. The results showed large variations with regards to the values of the parameters for each wastewater due to day-to-day variability in the biomass's response to substrate utilisation. For the two industrial wastewaters, the hydrolysis rate constant (kh) and half saturation constant for slowly biodegradable substrate (KX) were found to be in the range of 2.21-14.8 kg COD/kg biomass.day and 0.006-0.45 kg COD/kg biomass respectively. The maximum growth rate (μmax) and the half saturation rate constant for readily biodegradable substrates (KS) ranged between 1.21-7.3 day-1 and 0.004-0.89 kg COD/m3 respectively. The biomass growth yield (YX/S) and the endogenous metabolism coefficient (b) were found to be 0.3-0.57 kg biomass/kg COD and 0.001-0.41 day -1 respectively. The hydraulic retention time (HRT) and SRT were optimised in order to minimise the SBR volume and maximise the organic loading rate (OLR) of the SBR process. Two model wastewaters, glucose and ethanol, were used in the study. An experiment of eleven different SBR runs (HRT in the range of 0.25-4 days and SRT of 1-65.3 days) was carried on the glucose wastewater. Nine different SBR runs were carried out on ethanol wastewater (HRT in the range of 0.5-4 days and SRT of 1-73.6 days). The minimum HRT and SRT values for the successful operation for glucose wastewater treatment were 0.25 days and 3.1 days respectively while the minimum HRT and SRT for ethanol were 0.5 days and 4.9 days respectively. The highest corresponding OLR values from the minimum HRT and SRT which gave satisfactory process performance were 4.28 g COD/l.day and 4.14 g COD/l.day for glucose and ethanol wastewaters respectively, which are among the highest OLRs reported in the literature for aerobic conventional dispersed-growth processes. The calculated oxygen consumption and biomass production were found to depend on the SRT as well as the OLR, where in general, oxygen consumption increased while biomass production decreased at higher OLR. Batch tests were also carried out on the two model wastewaters for kinetic characterisation. The kinetic parameters for glucose wastewater were: 1.07-4.79 day -1 for μmax, 0.24-0.45 kg COD/m3 for KS, 0.04-0.1 day-1 and 0.47-0.6 kg biomass/kg COD for b and YX/S respectively. For ethanol wastewater, the kinetic parameters were: 0.99-2.3 day -1 for μmax, 0.001-0.04 kg COD/m3 for KS, 0.05-0.2 day-1 and 0.38-0.51 kg biomass/kg COD for b and YX/S respectively. A new mathematical model and procedure to calculate the periodic steady state of the SBR using a kinetic model of the biological process and values of the kinetic parameters was developed. This new procedure allows the direct calculation of the steady state profiles of biomass and substrate in the SBR without calculating the dynamics of the system from start up to steady state. The numerical accuracy of the procedure was discussed and the model was applied to show the effect of the operating parameters (SRT, HRT, length of the phases and number of cycles) on the steady state performance in terms of biomass and substrate concentrations. It was also shown how the model can be used for various applications like: optimisation of operating parameters for a minimum reactor volume; simulation of the competition between filamentous and floc-forming bacteria for bulking control; and calculation of the minimum volumetric mass-transfer coefficient required to maintain a desired oxygen concentration. In the end, the periodic steady state of the SBR was simulated for the industrial and model wastewaters at various values of the operating conditions (e.g. HRT, SRT, number of cycles) using the developed SBR model with values of kinetic parameters obtained from the various batch tests. The predicted model performance in terms of effluent quality and biomass concentration was compared with experimental results achieved during the treatment of the wastewaters. The simulation gave very good prediction of the extent of substrate removal for all the wastewaters. However, the prediction was not very accurate for biomass concentration. The study indicated that a good model prediction in terms of biomass production is strongly dependent on the values of the kinetic parameters especially b and YX/S.

The main body of the thesis is a detailed study of the practice of the legal regulation of water pollution, primarily between the period of 1 October 1983 and 31 August 1989, although reference is made to events preceding that period where necessary to provide a full assessment.

The limited underground water resources and the dramatic increase of fresh water consumption in Qatar forced the government to seek alternative ways to compensate for the lack of fresh water resources. Unfortunately, most of the currently available alternatives are costly in terms of excessive fuel consumption; also they require large capital investment and high maintenance cost. Such plants currently produce over 98% of the total fresh water in Qatar. This ratio may increase to 100% in the next few years. The main aim of this work is to investigate the most viable water desalination processes, which can produce sufficient, and a continuous supply of fresh water with low operation and construction costs. Climatic conditions and solar radiation in Qatar have been studied and analysed to determine the performance of any potential solar system applicable to this country. A technical and economical investigation into the current and common desalination methods with particular emphasis on the three main desalination systems including multistage flash, multiple effect distillation and reverse osmosis were conducted and included. A comprehensive literature survey on various water desalination methods was undertaken. The current experimental program was confined mainly to one novel type of tilted tray solar still system, namely pyramid tilted tray solar still, which was developed to increase productivity by increasing the receiving surface area of the still (the absorber) in order to collect the optimum amount of solar radiation. Two types of cover have also been selected and tested in this work, namely pyramid and dome shapes. These tilted tray solar stills were designed and constructed on a small scale and have been tested under controlled laboratory conditions at the University of Hertfordshire. Various parameters, which are likely to effect the still performance have been investigated. These include water flow rate, spacing between cover and tray surface, glass thickness, insulation layer, and inlet water temperature. Finally, a comparison of the stills performance characteristics of the two shapes has been carried out. The laboratory experimental results of hourly production revealed that pyramid type solar still yield higher distilled water output results than the dome type. However, the use of the pyramid shape with tilted tray solar can lead to further increase in the still productivity by optimising the orientation and surface area of the still absorber. The field experimental results of pyramid solar still, which were conducted under local climate conditions of Qatar, indicated clearly that solar desalination can be a suitable economical option, particularly for remote areas, where the fresh water demand is low and water transport is expensive. Moreover, a theoretical model was employed to predict the effects on solar still performance under three various parameters under typical climatic conditions of Qatar; These include the thermal insulation layer, the water depth and wind speed. Due to the economical reasons the dual-purpose multistage flash process will remain for the foreseeable future the preferred process, when fresh water and electricity demands are growing concurrently and rapidly.

Thesis PlanB (M.S.)--University of Wisconsin--Stout, 2007. / Includes bibliographical references.