A broad based approach has been used to assess the impact of discharges to rivers from surface water sewers, with the primary objective of determining whether such discharges have a measurable impact on water quality. Three parameters, each reflecting the effects of intermittent pollution, were included in a field work programme of biological and chemical sampling and analysis which covered 47 sewer outfall sites. These parameters were the numbers and types of benthic macroinvertebrates upstream and downstream of the outfalls, the concentrations of metals in sediments, and the concentrations of metals in algae upstream and downstream of the outfalls. Information on the sewered catchments was collected from Local Authorities and by observation of the time of sampling, and includes catchment areas, land uses, evidence of connection to the foul system, and receiving water quality classification. The methods used for site selection, sampling, laboratory analysis and data analysis are fully described, and the survey results presented. Statistical and graphical analysis of the biological data, with the aid of BMWP scores, showed that there was a small but persistent fall in water quality downstream of the studied outfalls. Further analysis including the catchment information indicated that initial water quality, sewered catchment size, receiving stream size, and catchment land use were important factors in determining the impact. Finally, the survey results were used to produce guidelines for the estimation of surface water sewer discharge impacts from knowledge of the catchment characteristics, so that planning authorities can consider water quality when new drainage systems are designed.

This research identifies factors which influence the consumption of potable water supplied to customers' property. A complete spectrum of the customer base is examined including household, commercial and industrial properties. The research considers information from around the world, particularly demand management and tariff related projects from North America. A device termed the Flow Moderator was developed and proven, with extensive trials, to conserve water at a rate equivalent to 40 litres/property/day whilst maintaining standards-of-service considerably in excess of Regulatory requirements. A detailed appraisal of the Moderator underlines the costs and benefits available to the industry through deliberate application of even mild demand management. More radically the concept of a charging policy utilising the Moderator is developed and appraised. Advantages include the lower costs of conventional fixed-price charging systems coupled with the conservation and equitability aspects associated with metering. Explanatory models were developed linking consumption to a range of variables demonstrated that households served by a communal water service-pipe (known in the UK as a shared supply) are subject to associated restrictions equivalent to -180 litres/property/day. The research confirmed that occupancy levels were a significant predictive element for household, commercial and industrial customers. The occurrence of on-property leakage was also demonstrated to be a significant factor recorded as an event which offers considerable scope for demand management in its own right.

This collection of papers records a series of studies, carried out over a period of some 50 years, on two aspects of river pollution control - the prevention of pollution by sewage biological filtration and the monitoring of river pollution by biological surveillance. The earlier studies were carried out to develop methods of controlling flies which bred in the filters and caused serious nuisance and possible public health hazard, when they dispersed to surrounding villages. Although the application of insecticides proved effective as an alleviate measure, because it resulted in only a temporary disturbance of the ecological balance, it was considered ecologically unsound as a long-term solution. Subsequent investigations showed that the fly populations in filters were largely determined by the amount of food available to the grazing larval stage in the form of filter film. It was also established that the winter deterioration in filter performance was due to the excessive accumulation of film. Subsequent investigations were therefore carried out to determine the factors responsible for the accumulation of film in different types of filter. Methods of filtration which were considered to control film accumulation by increasing the flushing action of the sewage, were found to control fungal film by creating nutrient limiting conditions. In some filters increasing the hydraulic flushing reduced the grazing fauna population in the surface layers and resulted in an increase in film. The results of these investigations were successfully applied in modifying filters and in the design of a Double Filtration process. These studies on biological filters lead to the conclusion that they should be designed and operated as ecological systems and not merely as hydraulic ones. Studies on the effects of sewage effluents on Birmingham streams confirmed the findings of earlier workers.

This thesis presents a thorough and principled investigation into the application of artificial neural networks to the biological monitoring of freshwater. It contains original ideas on the classification and interpretation of benthic macroinvertebrates, and aims to demonstrate their superiority over the biotic systems currently used in the UK to report river water quality. The conceptual basis of a new biological classification system is described, and a full review and analysis of a number of river data sets is presented. The biological classification is compared to the common biotic systems using data from the Upper Trent catchment. This data contained 292 expertly classified invertebrate samples identified to mixed taxonomic levels. The neural network experimental work concentrates on the classification of the invertebrate samples into biological class, where only a subset of the sample is used to form the classification. Other experimentation is conducted into the identification of novel input samples, the classification of samples from different biotopes and the use of prior information in the neural network models. The biological classification is shown to provide an intuitive interpretation of a graphical representation, generated without reference to the class labels, of the Upper Trent data. The selection of key indicator taxa is considered using three different approaches; one novel, one from information theory and one from classical statistical methods. Good indicators of quality class based on these analyses are found to be in good agreement with those chosen by a domain expert. The change in information associated with different levels of identification and enumeration of taxa is quantified. The feasibility of using neural network classifiers and predictors to develop numeric criteria for the biological assessment of sediment contamination in the Great Lakes is also investigated.

In this study, the amphipod Corophium volutator and the polychaete Arenicola marina were evaluated as test organisms for use in sediment toxicity tests by adapting standard protocols developed by the EPA/COE and Thain et al. (1994) respectively for conducting 10-day sediment toxicity tests. Although these species have been used to assess the toxicity of marine and estuarine sediments, the detailed ecotoxicologies of these animals are not well documented. In particular, the effects of specific contaminants of known concentrations on this bioassay are not known. Here, I report several experiments carried out using clean intertidal sediment contaminated with the heavy metals copper, zinc and cadmium, and employing the Corophium and the Arenicola bioassay protocol. Concentrations of copper, zinc and cadmium were determined in tissues of Corophium exposed for 4 and 10 days to contaminated sediment using four protocols to allow for any material present in the gut. Significant differences in metal concentrations occurred between the protocols where gut contents were removed and those where they were left intact. These findings have implications for the way in which analyses of metal burdens are carried out for invertebrates in ecotoxicological work. Corophium survival in seawater with dissolved copper, zinc and cadmium was higher in the presence of sediment than without sediment, although the concentrations of these metals in Corophium tissues were the same in both cases. Bioconcentration factors (BCF) were inversely related to seawater concentrations of copper, zinc and cadium, with the lowest exposure concentration, (0.1 mg l-1 for both copper and zinc, 0.01 mg l-1 cadmium) having the highest BCF. Both live amphipods and those that had died accumulated copper, zinc and cadmium in their bodies during the bioassay, and bioconcentration factors were always higher for dead than for living amphipods for each metal.

Depuis de nombreuses années, les métaux traces ont fait l’objet de recherches importantes dans les domaines de l’environnement et de l’écotoxicologie. Le mercure (Hg), élément trace, a été étudié depuis l’époque où sa responsabilité dans la contamination de la baie de Minamata au sud-ouest du japon a été mise en évidence. Il est le seul élément chimique dont l’introduction dans le milieu marin par l’activité humaine ait entraîné mort d’homme. Les sédiments jouent un rôle important dans le cycle biogéochimique du mercure en milieu aquatique, qui sont considérés comme piège de la contamination par le mercure, les sulfures jouent un rôle important dans le contrôle de sa spéciation et les risques environnementaux générés dans les milieux aquatiques. Le mercure peut être transformé sous ses formes methylées et être remobilisé ou encore transféré dans la chaine trophique. Dans certaines conditions les sédiments peuvent être aussi une source de contamination par le mercure. La première partie de cette étude est axée sur la mise au point d’une nouvelle méthode de mesure et de spéciation du mercure dans les sédiments en utilisant, le couplage éthylation en solution du mercure et du methylmercure avec la méthode Headspace et Headspace avec Trap (piège Tenax), séparation par Chromatographie Gaz et détection par la technique de spectroscopie de fluorescence atomique à vapeur froide (CV-AFS : Cold Vapor Atomic Fluorescence Spectroscopy). L’étude de terrain été réalisée dans les canaux « Deûle et Lys » de la région Nord-Pas de Calais, côté français et dans deux fleuves côté République Tchèque « le Morava et le Jihlava ». Les techniques d´échantillonnages classiques des sédiments par carottage et à l´aide des méthodes de diffusion sur gel DGT (Diffusion Gradient Thin film) pour la mesure du mercure in situ ont été utilisées. La méthode DGT permet de déterminer le métal dissous labile (ion libre, complexes minéraux et complexes organiques peu stables) et dépend du type de capteur DGT utilisé. Différents gels ont été utilisés et comparés pour la détermination du mercure: Spheron-Thiol, Duolit GT-73 et TiO2. Les résultats obtenus montrent que le Canal de la Deûle est un site caractérisé par une contamination très forte et ancienne. Les transformations et la partition des espèces du mercure ont été évaluées grâce à l´utilisation de traceurs isotopiques (199IHg et 201MeHg) en même temps que la réactivité biogéochimique du sédiment. Les comportements respectifs des espèces naturelles (endogènes) et ajoutées (exogènes) du mercure ont été comparés pour chaque couche du sédiment. / Mercury (Hg) is naturally occurring toxic element; however global mercury emissions are dominated by anthropogenic sources. The global cycle of mercury has seen an increase in mercury deposition, especially in aquatic ecosystems, since the beginning of the industrial revolution. First part of the thesis summarizes the source of mercury, its properties and toxicity from the general point of view, but also the current state of knowledge on the biogeochemical cycle of mercury and in particular behaviour of mercury inside the sediments of the aquatic environment and factors influencing its transformation into methylated form. The sediment in aquatic systems may acts as the ultimate sink, where mercury in its various complexes is deposited. The mercury in sediments can then be converted to its more toxic organic form, methylmercury (MeHg), by the transformation processes controlled by various physical, chemical and biological factors. More over remobilization of mercury species from sediments is possible due to diffusion and resuspension and so sediments may act as potential source of mercury for aquatic biota. Bioaccumulation and biomagnifications can then continue up the food chain where humans, among other animals, consume the organic mercury. It is clear that determination of total mercury is not sufficient to understand its fate in the environment; determination of MeHg provides very useful additional information. The sensitive and precise analytical method for MeHg determination is necessary. The methodological part of the thesis deal with the methods for determination of mercury species in sediments. The method for methylmercury determination in sediments using automated Headspace sampler equipped with Trap and coupled with Gas Chromatography and Atomic Fluorescence Detector was developed and is define. The special attention is also given to the necessity of clean sampling procedures and the proper storage and pre-treatment of the samples and the field study of Hg distribution in sediments. The mercury contamination of sediments from the South Moravia and Northern France are compared. The mercury species and other elements (Fe, Mn, S) were analysed in sediments and/or pore water and/or surface water collected from the sampling sites in the Deûle and Lys River (France) and Jihlava and Morava River (Czech Republic). In order to better assess the mercury contamination of aquatic ecosystem, the pore water concentration could be evaluated to understand the availability of mercury from sediment. The use of diffusive gradient in thin film (DGT) technique is applied to measure pore water mercury concentration in river sediments. Different resins gels for mercury determination are used: Spheron-Thiol, Duolite GT-73 and TiO2. River Deûle act as a sink for enormous anthropogenic Hg from the industrial activities and is considered as a potential significant source of methylmercury to the surrounding environment. The last part of thesis deals with the application of well-established isotope experiments to study methylation/demethylation processes in sediments of Deûle River. For this purpose, species-specific isotopically enriched tracers in the form of inorganic mercury IHg (199Hg) and MeHg (201MeHg) have been added to the sediment slurries. Mercury labelled species were used as the tracers to follow their chemical fate and calculate the extent of the transformation reaction yield occurring during the 24 hours experiment. This experiment methodology is refined by applying advanced matrix algebra to resolve the contributions of several different enriched stable isotope species specific tracers to the isotope pattern found, making the calculation of methylation/demethylation rates possible.

Ce travail s’inscrit dans le cadre du programme Seine-Aval IV projet TOXSEINE et porte sur l’étude de la dynamique, le comportement et la toxicité des éléments traces métalliques à l’interface eau-sédiment dans l’estuaire de la Seine. Notre étude a été menée sur différents sites de Poses à l’amont jusqu’à l’embouchure (Vasière Nord). Cette étude nous a permis de mettre en évidence une contamination relativement importante des sédiments par des composés métalliques principalement le mercure, le cuivre, le plomb, le cadmium, le zinc et le nickel, en particulier l’amont de l’estuaire. Une autre partie du travail a été consacré à l’étude de la disponibilité et la toxicité de ces métaux, en utilisant des bioessais (test microtox) et par la détermination des indices de toxicité et. Toutefois ces éléments traces métalliques accumulés au niveau des sédiments représentent une source de contamination et une menace potentielle pour l’écosystème aquatique, en particulier en cas de remise en suspension lors de leur relargage et leur désorption suite à l’effet de marée, le trafic maritime ou aux activités de dragage. Pour ces raisons la mobilité des ETM a été étudiée tenant en compte les phénomènes d’adsorption, de résorption et la cinétique de relargage des métaux. Les résultats indiquent une labilité importante des métaux (Cd, Pb, Cu) et une bonne corrélation entre contamination chimique et réponse biologique. / The present work is a part of TOXSEINE project included in “Seine-aval IV Program”. The main focal points of the research are: study of the behavior and the toxicity of trace metals at water-sediment interface of the Seine estuary. Our work is conducted on different sites along the estuary reaching the mudflat of the river. The following study has revealed high levels of metal contamination in Seine sediment especially with Hg, Cd, Cu, Pb, Zn particularly in the upstream river. Other part of the work is devoted for the study of the disponibility and toxicity of metals by calculation of toxicity index and the use of bioessay (Microtox test). The accumulated trace metals in sediment represent a source of pollution and a potential threat to aquatic ecosystem especially during their release due to sediment resuspension caused by tide effect, traffic boat and dredging activities. For these reasons, the mobility of ETM is studied taking into consideration: adsorption phenomena, desorption, kinetics of metal release. The results have indicated an important lability of metals (Cd, Pb, Cu) and positive correlation between the chemical contamination and the biological response.

La présente étude considère les conséquences sur la mobilité des HAP de trois actions face à un lit sédimentaire contaminé : l’absence d’action, l’ouverture du canal à la navigation et son curage. Pour ce faire, des profils de concentration en HAP libres dans la colonne sédimentaire et la colonne d’eau sont obtenus par le déploiement in situ de préleveurs passifs en plusieurs points du cours d’eau, dont l’un exposé à la navigation. Un suivi dans le temps est effectué, avant, pendant et après curage du cours d’eau. L’étude de l’impact de l’âge de la matrice sédimentaire et de l’activité micro-biologique sur le transfert de HAP vers la colonne d’eau est effectuée à travers une remise en suspension en conditions contrôlées. On constate alors que sur un tronçon homogène de colonne sédimentaire, la sorption des HAP augmente avec l’âge de la matrice. Cependant, dans le cas d’une discontinuité dans la nature de la matrice, de soudaines variations de concentrations en HAP libres peuvent survenir dans l’eau interstitielle, et une diffusion des HAP libres se met alors en place. Cette diffusion des HAP est plus sensible encore à l’interface eau-sediment, où on observe un transfert des HAP vers la colonne d’eau. La navigation diminue la couche limite de diffusion et renforce donc ces transferts. Le curage du lit sédimentaire quant à lui entraine un relargage massif de HAP libres dans la colonne d’eau. Ces HAP sont refixés par le matériel en suspension, mais cette re-fixation est précaire, les HAP pouvant être à nouveau libérés par la biodégradation du matériel en suspension assurant leur transport. / This study presents the consequences, on PAH mobility, of 3 possible actions a watercourse administrator can take while facing a contaminated sedimentary bed: no action, the opening of the canal to navigation and its dredging. In this respect, concentration rates of free Polycyclic Aromatic Hydrocarbons have been obtained in the sedimentary column and in the water column by displaying passive samplers on different locations along the watercourse, one of them being exposed to navigation. A follow-up is made before, during and after the dredging of the watercourse. The impact of the age of the sedimentary matrix and of the microbiologic activity on the PAH transfer to the water column is studied through a remobilized sediment in batch experiments. It is then observed that the PAH sorption increases with the age of the matrix in one homogenous section of the sedimentary column. However, in case of a discontinuity in the matrix nature, sudden variations of free PAH concentration can occur in interstitial water. It results in a diffusion of free PAH. This PAH diffusion is even more sensitive to the water-sediment interface, on which we can observe a transfer of the PAH towards the water column. Navigation decreases the boundary layer and thus reinforces theses transfers.The dredging of the sediment bed results in a large release of free PAH in the water column. Those PAH are fixed again by the suspended material. Yet, this new fixation is frail : the PAH can be freed once more by the biodegradation of the suspended material transporting them.

Anaerobic processing has become recognized as a simple and energy-efficient means of treating and stabilizing many high strength organic industrial wastes and is also not subjected to the operating limitations of aerobic processes. The literature review presented in this thesis outlines the advances made in the understanding of the microbiology and biochemistry of the process and the considerable advances in reactor configurations in achieving high SRTIHRT ratios. The efficacy of the anaerobic process is dependent on maintaining a high biomass concentration in the reactor, which in tum is dependent on the performance of the solids separator. The anaerobic contact process employs gravity settling for solid-liquid separation but the poor settleability of the anaerobic sludge may result in a poor performance of the contact process. By employing a much more efficient separation process such as ultrafiltration (UF), the performance of the anaerobic system can be significantly improved. In this study, therefore, a new method of operating a completely mixed anaerobic digester using a crossflow UF membrane technique was investigated in order to control the concentration of active biomass in the reactor and to determine the extent of any other advantages that can be gained over other reactor configurations. The study was carried out in four stages. In the first stage the performance of an anaerobic contact digester using a crossflow UF membrane technique was investigated for brewery wastewater treatment. The results obtained from this stage showed that under steady-state conditions, at an influent substrate concentration of approximately 120 g COD/l (100 g BOD/I) with a hydraulic retention time of 4.2 days giving an organic loading rate of 28.5 kg COO/m3.d , overall COO and BOD removal efficiencies of 99% and almost 100% respectively were achieved and the system had not reached its maximum loading capacity. Throughout the operation, HRT was maintained in the range of 2.5-4.2 days, largely determined by the flux rate. Microbiological analyses including Microscopic Count, Plate Count, Most Probable Number and Specific Methanogenic Activity test confirmed that there was almost no biomass loss through the membrane which, in tum, resulted in the maintenance of a high stability of the system under load changes. The UF membrane showed a remarkable consistency throughout the study. retaining a high concentration of active biomass in the digester and demonstrating that fouling by anaerobic biomass will reach a limiting level. In the second stage of the study the effect of Mixed Liquor Suspended Solids (MLSS) on the kinetics of the membrane reactor was investigated. The results showed that the kinetic coefficients estimated from the four steady-state runs had slight variations from each other but which could be mainly due to the changes in the numbers and the dominant species throughout the operation of the system. The increase in the MLSS concentrations did not significantly affect the kinetics of the system, In the third stage of the study the Specific Methanogenic Activity (SMA) technique was used to determine the methane production capacity of the membrane reactor, thus allowing suitable OLRs to be applied and to assess the effects of MLSS concentration on the activity of acetoclastic methanogenic bacteria in the digester. The results showed that any deterioration in acetoclastic methanogenic capacity of the system can be improved by increasing the sludge wastage rate. Ratios of the actual methane production rate to the potential methane production rate of less than 0.7 were found to be satisfactory in order to run the system efficiently in terms of COD removal and methane yield. In the final stage of the study the possible effects that membrane systems may have on the microbial population in the reactor was investigated. Therefore, microscopic examinations have frequently been carried out in order to determine the effects of the new configuration on any variation in the morphology or on the properties of methanogens as well as any change in the number of non-methanogens throughout the operation of the membrane reactor. This investigation showed that the membrane system configuration did have an apparent effect on the dominant methanogenic species throughout operation of the membrane reactor. For example Methanococcus species were the most dominant group at the beginning of the start-up period, becoming the third most dominant group at the end of the study. As a result, studying the changes in the number of viable methanogens and the dominant species may help to determine a reason for the deterioration in performance of a digester.

This study involved the development and evaluation of a number of biomonitoring techniques for use with members of the Ulvaceae, Enteromorpha intestinalis (L.) Link, and Viva iactuca (L.). The techniques included both previously established ones and those which required development. The two main procedures developed for these algae were the neutral red retention technique (making use of a vital stain) and the ion leakage Health Index (based upon electrolyte leakage). Following optimisation both were used to produce quantitative structure-activity relationships (QSARs) for a series of n-alcohols using log Kow as the physicochemical parameter. The resultant QSARs were statistically indistinguishable with line equations of -0.88 log Kow + 2.87 and -0.95 log Kow + 2.83 respectively, with r values of 0.98, suggesting that both reflect the same non-specific narcotic effect on membrane integrity. However the neutral red retention technique was less useful than the Health Index with low reproducibility and is therefore unsuitable for use as an environmental biomonitor. The effects of other compounds with specific modes of action were established using the ion leakage technique, the high toxicity of the antifouling compound tributyltin being reflected in the Health Index. Further development of the ion leakage technique involved inductively coupled - plasma mass spectrometry (ICP/MS) in the identification of ions lost during leakage. Synergistic toxicity was investigated exposing the algae to UV light and anthracene, simulating photo-induced toxicity. No photo-induced toxicity was observed although UV exposure did reduce the Health Index. An environmental assessment was carried out for algae from clean sites and organically and inorganically polluted sites, comparing the Health Index with other measures of health and bioaccumulation data. A long term study of a clean site showed the algal Health Index to be influenced by seasonally dependent physical parameters, but reflected reduced health in algae exposed environmentally to organic pollutants. Algae exposed to long term heavy metal pollution in the Fal Estuary had 'normal',. Health Indices, however chlorophyll fluorescence induction techniques did highlight a reduced photosynthetic efficiency in these algae. The ion leakage technique has potentially a wide application in field and laboratory based biomonitoring and direct toxicity studies. Chlorophyll fluorescence analysis was also shown to be useful although it requires further investigation and evaluation.