This thesis develops online feedback control of chlorine residuals performing at the lower level of a hierarchical structure of integrated quantity and quality control in drinking water distribution systems (DWDS), which provides a practical solution for online water quality control in DWDS. Input-output and state-space models of the chlorine residuals are developed from mathematical models of chlorine residual dynamics. The existing path analysis algorithm is extended and utilized to obtain the parameter structure. Joint parameter and model structure error estimation is developed using bounding approach based on a point-parametric model. The uncertainty radius of the system is outlined through robust output prediction, through which requirements for model accuracy from robust model predictive control (MFC) are explicitly imposed on model estimation. Hence, an integrated design of controller and model estimation is achieved. MFC is applied for chlorine residual control based on the set-bounded model. To fulfil output constraints under system uncertainties, safety zones are employed, which are designed from an online evaluation of the uncertainty scenarios of the system, to restrict the output constraints. The safety zones can be obtained by solving a nonlinear constrained optimization problem using a significantly simplified relaxation-gain algorithm. The resulting robust MFC (RMPC) is decentralized assuming communication among the decentralized RMPCs is available. The proposed methodology is verified by applying it to a simulated benchmark DWDS. Simulation study of model estimation and RMPC operation is presented and discussed.

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Scale formation in domestic appliances is a widespread problem in the UK. This project has focussed on calcium carbonate scale formation in electric showers. A literature survey identified that CaCO; deposition on heated surfaces could be controlled by chemical or non chemical methods, each with various degrees of effectiveness. One of the most effective control methods was the addition of chemicals, although this may not be the most suitable option for the domestic environment. So here the chemical inhibitors tested were used for a benchmark for all the other studies. Two laboratory tests were involved t allow u to study CaCO; precipitation and scale formation. The effect of chemical additives on CaCO; precipitation was investigated using a jar tester. The longest delay to precipitation was obtained by polyacrylic acid dosing, closely followed by zinc. To study CaCO; formation on a heated surface, a rapid scaling test was developed. This test was conducted at 42°C and 70°C to examine and compare a range of treatment options, including chemical dosing, electrolytic, magnetic and electronic water conditioning and low fouling surfaces. From the options examined, the most successful was electrolytic dosing of zinc/copper media with over 95% reduction in scaling at both temperatures. Further, the use of low fouling surfaces, such as Diamond - like carbon coating could also potentially be used in electric showers. Reduction in scaling achieved on this surface was on average 68%. Surface properties of the materials were analysed using an atomic force microscope and their relationship with the scaling behaviour of the surfaces examined. The scaling rates at both temperatures typically increased with increasing adhesion force but no clear relationship was found between the roughness of the surfaces and their scaling behaviour. The relationship between CaCO3 precipitation and scale formation in synthetic solution and natural hard water was also explored here. The induction period in natural hard water was 55 minutes longer and the scaling rate 40% lower than i synthetic hard solution of similar composition. In addition, two shower test rigs, one based at Cranfield University and the other in Attleborough were used in this study. These were used primarily to enable the compilation of background data on scale formation in electric showers, where it was found that the design of the unit has a significant influence on the scale formation. The test rig was also used t test the strategies identified during the laboratory phase of the work. It was found that electrolytic zinc dosing reduced scaling by up to 54%, depending on the shower unit design.

A novel incubator, which utilises latent heat energy storage, has been researched, designed and developed. Without the need to rely on an electricity supply, the new incubator will enable reliable microbiological testing to be conducted in low resource settings, as found in many developing countries. Microbiological contamination of drinking water is a significant cause of death and disease in developing countries. Water quality monitoring is an important aspect of water safety. There is a need for more widespread usage of microbiological testing, and the lack of a reliable method for incubating tests is a barrier where infrastructure and resources are limited. This thesis documents research to develop an incubator that is appropriate for use in low resource settings. This utilises a phase change material (PCM), which enables latent heat energy storage in order to maintain incubation temperature. It has been demonstrated experimentally that such an incubator can be used to perform microbial water quality monitoring using an enzyme substrate test, without compromising performance of the test. It delivers reliable operation across a range of environmental conditions that are likely to be encountered in developing countries, including protecting the test against overheating in hot climates. It does not require an electricity supply for operation. Research in several fields has been undertaken to inform and evaluate the development of the PCM incubator. Key original contributions of this research include: 1) Evaluation of incubation temperature standards for E. coli testing using enzyme substrate tests; 2) Investigation into the effect of temperature on growth characteristics of individual E. coli organisms in a water test; 3) Development of a model to predict test result at variable incubation temperature; 4) Examination of PCMs suitable for incubation of microbiological tests; 5) Analysis of ambient temperature incubation as a means of conducting microbiological analysis; 6) Design, development and evaluation of a PCM incubator suitable for use in low resource settings. The PCM incubator described herein has the potential to enable water quality monitoring to be performed in low resource areas where water is largely untested and which also suffer from the greatest impact on health due to contaminated water. This technology also has the potential to be applied in other fields, such as clinical microbiology or environmental monitoring. Ultimately, by enabling microbiological testing, latent heat incubation by means of a PCM incubator has the potential to improve human health in low resource areas of developing countries. Keywords: Incubator; phase change material (PCM); latent heat energy storage; water testing; drinking water quality; developing countries; low resource settings; Escherichia coli; growth rate; lag phase; relative lag time; Colilert®, Aquatest

The management of mineral scale is a challenge in many industrial fields and environmental issues relating to eutrophication are leading industry to develop environmentally-friendly solutions to scale control. The determination of the strategy of inhibition is a real challenge as many factors influence the formation of calcium carbonate formation and affect the performance of scale inhibitors. The processes of CaC03 formation on a surface have been studied. The mechanisms of inhibition of three green (Carboxymethyl Inulin, CMI, Polymaleic acid, PMA and Polyaspartic acid, PA) and one conventional (Polyphosphinocarboxylic acid, PPCA) scale inhibitors of calcium carbonate nucleation and growth have been investigated. The interactions between the chemicals and the surface have been studied by chronoamperometry. The use of surface analysis enabled these interactions to be characterised. The in-situ electrochemical flow cell permitted the characterisation of the crystals formed (size, number and surface coverage of the electrode) and the affinity of the chemicals to inhibit the nucleation and/or the growth to be determined. Important information on the different effects of scale inhibitors on CaC03 polymorphs has been found by use of Synchrotron X-Ray Diffraction (SXRD) as an in-situ method for crystal characterisation. The inhibitors partly inhibit the deposition of CaC03 by forming a film on the deposition surface. The interactions between the inhibitors and the metal surface occur via the cations Ca2+ and/or Mg2+. The adsorption of the chemicals on the crystals ofCaC03 has been investigated and it appears that the PPCA, PMA and PA act by blocking the growth sites of the crystals. Each inhibitor exhibits an affinity to the surface of deposition and with the CaC03 crystals but to a different extent resulting in different inhibition efficiencies. The PPCA affected greatly the deposition of CaC03 and PA and PMA exhibited similar effects. Nevertheless the PA is more efficient when it is present during the nucleation step or early crystallisation whereas PMA acts more during the growth process. The SXRD permitted three steps of growth to be detected in the non-inhibited case and PMA, PA, CMI act by reducing the growth of the different planes whereas the PPCA totally inhibited two main crystal planes (the aragonite (032) and the vaterite (300» and an acceleration of the growth of the calcite C(006)) and of the aragonite A( Ill) was observed.

Dans le Nord de la France, les eaux de la nappe de la craie sénoturonienne situées au sud de Lille (Emmerin, Houplin-Ancoisne, les Ansereuilles et Salomé) sont confrontées à l'augmentation du sélénium dépassant la limite de potabilité (10 μg.L-1) avec une variabilité spatiale et locale qui atteint parfois 60 μg.L-1. Les différents niveaux lithologiques, à l'exception de la craie sénonienne, contiennent du sélénium naturel. Les valeurs maximales mesurées se singularisent dans les niveaux argileux de l'Yprésien (4.87 mg/kg), les argiles alluvionnaires (4.8 mg/kg) et les sédiments des cours d'eau avec une part importante d'origine anthropique (entre 2.1 à 15.8 mg/kg). Le sélénium a une grande affinité à la matière organique. Parmi ses phases porteuses, la fraction soluble/échangeable est la fraction de sélénium la plus mobile. Les isotopes du strontium couplés avec Ca/Sr et Mg/Sr ainsi que les rapports isotopiques de strontium 87Sr/86 Sr ont été utilisés pour identifier les principales masses d'eau souterraines et leurs mélanges. Les conditions du milieu oxydantes ou réductrices sont contrôlées par les variations du niveau piézométrique qui est sous influence des variations inter-annuelles et saisonnières de la nappe et les pompages. Néanmoins, chaque champ captant se distingue par ses conditions géologiques et hydro-géochimiques. La mobilisation du sélénium peut se faire par le biais des eaux d'infiltration (par le haut), les fluctuations de la nappe (par le bas), les transferts latéraux (interconnexions entre forages par effet des gradients hydrauliques) et les mélanges des eaux provenant des secteurs avoisinants. / In north France, the concentration of selenium in the groundwater of the Turonian-Senonian chalk layers located in the south of Lille (Emmerin, Houplin -Ancoisne , the Ansereuilles and Salome) exceeds drinking-water limit of 10 µg/L and reaches 60 μg/L in some located small areas. The various lithological levels, except the Senonian chalk, contain natural selenium. The maximum measured values stand out in the Ypresian clay layer (4.87 mg/kg), alluvial clays (4.8 mg/kg) and sediments of rivers with important influence of anthropogenic origin (between 2.1 to 15.8 mg/kg). Selenium has a high affinity to the organic material. The soluble/exchangeable fraction is the most mobile selenium one. Strontium isotopes coupled with Ca/Sr and Mg/Sr and strontium isotopes ratios 87Sr/86Sr were used to identify the main groundwater bodies and theirs mixtures. Oxidizing or reducing environment conditions are controlled by the variations in the groundwater level which is influenced by the inter-annual and seasonal changes in the water and pumping process. However, each well field is characterized by its geological and hydro–geochemical conditions. The selenium may be mobilized through seepage (from the top), water levels variations (from the bottom), lateral transfers (interconnections between boreholes due to hydraulic gradients) and mixtures of water from surrounding areas.

Le recyclage des eaux constitue une bonne option pour une majeure partie des eaux usées résiduaires urbaines rejetées dans le milieu naturel. L'eau grise compose 61% du flux total des eaux usées, elle provient essentiellement de l’usage en salle de bain, en cuisine et lavage de linge (machines à laver). Une fois traitée, cette eau peut être facilement réutilisée à l'exclusion de l'office comme eau potable. Ce travail de recherche explore les possibilités de traitement des eaux grises et de choisir les techniques de traitement les plus efficaces et les moins coûteuses. Nous avons identifié les différents types de procédés de traitement, puis nous avons choisi les systèmes qui peuvent fournir à la fois de l'efficacité et la faisabilité pour le traitement des eaux grises à faible charge. Après avoir sélectionné deux systèmes de traitement, nous les avons fusionnés en un seul système. Ces deux systèmes s'appuient fortement sur les procédés d'adsorption. Différents types d'adsorbants, à faible coût et adapté aux pays en voie de développement ont été testés : résidus de briques, du charbon actif et différentes granulométries de sable. La demande chimique en oxygène, la turbidité et le pourcentage d'élimination des agents actifs ont été utilisés pour juger l’efficacité de chaque adsorbant. Après avoir sélectionné le support de filtration, nous nous sommes concentrés sur le concept de phytoremédiation en utilisant différents types de plantes. Le choix s’est porté sur la Lavande pour réaliser les expérimentations. Deux paramètres ont été suivis, la demande chimique en oxygène et la turbidité, pour juger l’efficacité du traitement sur un système pilote.Les résultats obtenus montrent que le pilote est opérationnel et permet de récupérer une grande quantité d'eau qui pourrait être réutilisée dans les toilettes ou l'irrigation. La dimension sociétale est un élément très important dans le succès de tout nouveau système de traitement destiné à une large utilisation par la population ou la collectivité. En fonction de l'option choisie, des enquêtes ont été réalisées pour percevoir la volonté d’engagement dans une telle voie de traitement. / Greywater constitutes 61% of the total wastewater stream that includes bathroom waters, kitchen water and washing machines. When treated, this source can be easily reused in wide options excluding potable uses. This study explores the opportunities to treat greywater and try to choose the most efficient yet cheap treatment systems.An overall view of different types of treatment systems was conducted, and then we chose which systems could deliver both efficiency and feasibility for low load greywater. After selecting two types of treatment systems, we needed to merge both of them into one system that will enhance the treatment efficiency. These two systems rely tightly on adsorption that is why we wanted to identify which adsorbent can offer the best percentage of pollutants elimination but still fit in the low budget of low income countries. Different types of adsorbent were tested: different bricks residues, activated carbons and different grain size of sand. Chemical oxygen demand, turbidity and the percentage of elimination of active agents were used to judge their effectiveness. After selecting fine sand and coarse sand, a phytoremediation concept was used, this require testing different type of plants. Lavender was then selected to be part of our system. Chemical oxygen demand and turbidity were used to judge whether or not our system could deliver good results. After running these two tests, our pilot showed great results and recovered great amount of water that could be then used in different reuse options like toilet flushing or irrigation. Because user’s opinion and social acceptance is a threat to any new treatment system, we visited some of the nearest hotels and resorts to see their willingness to engage in such treatment path. In addition, cost is always a major throwback to any new treatment system; therefore, cost benefit analysis was used to ensure the feasibility of our pilot.

La présence des perturbateurs endocriniens dans le milieu aquatique a suscité des préoccupations croissantes en raison de leurs effets néfastes potentiels sur les écosystèmes et les humains. Celles-ci sont généralement présents à l’état de trace (ng/L), dans des matrices aqueuses complexes, telles que les eaux de surfaces ce qui rend l’analyse difficile. Dans ce travail, on a mis au point une méthode analytique pour la détermination simultanée de 13 substances perturbatrices endocriniennes (PEs) dans l’eau, dont 5 estrogènes stéroïdes, 1 progestérone, 1 androgène et 6 composées phénoliques, , par la chromatographie gazeuse couplée à la spectrométrie de masse (GC-MS). La méthode a été validée. Les limites de quantification étaient respectivement de 1 ng/L et de 5 à 50 ng/L pour les composés phénoliques et les hormones. La méthode mise au point a été appliquée pour évaluer le niveau de contamination des PEs ciblées dans de nombreux sites du Nord de la France et de la Tunisie. La majorité des composés considérés ont été détectés dans les sites d'échantillonnage. La dernière partie de ce travail est consacrée à l'étude de faisabilité d'élimination du PEs par des techniques d'adsorption sur les résidus d’une brique modifiée et la bio-rémédiation par l’algue bleu-vert (Spiruline). / The occurrence of endocrine-disrupting compounds in the aquatic environment has brought increasing concern due to their potential adverse impacts on ecosystems and humans. These compounds are generally present in complex water matrices, such as surface waters at trace levels (ng/L) making their analysis difficult. In this work, an analytical method for the simultaneous determination of 13 endocrine disrupting chemicals (EDCs), including 5 steroid estrogens, 1 progestogen, 1 androgen and 6 endocrine-disrupting phenols in water was developed using solid phase extraction (SPE), derivatization and gas chromatography-mass spectrometry (GC-MS).The method was validated by spiking the 13 EDCs to the interest matrix. The limits of quantification were 1 ng/L and 5-50 ng/L for phenolic compounds and hormones respectively. The validated method was applied to assess the contamination level of the targeted EDCs in many sites in Northern France and in Tunisia. The majority of the considered compounds were detected in the different sampling sites. The last part of this work is the feasibility study for the elimination of PE by adsorption techniques on modified brick residues and bio-remediation by blue-green algae (SPIRULINA).

La rivière Marque est un petit cours d’eau localisé sur un bassin versant péri-urbain du Nord de la France, traversant des zones agricoles et urbaines. Au niveau de Villeneuve d’Ascq, cette rivière reçoit les eaux de deux principaux ouvrages de traitement de l’eau : (i) les eaux urbaines traitées de la station d’épuration de Villeneuve d’Ascq ; et (ii) les eaux du lac du Héron qui est un bassin d’orage. Afin d’améliorer la compréhension de la rivière dans cette zone, des suivis basse et haute fréquences ont été mis en place en 2014. En complément, une bouée instrumentée appartenant à l’Agence de l’Eau Artois-Picardie a été déployée en 2015 sur le lac. Une approche multi-traceurs a été envisagée pour tenter d’identifier les différentes pressions sur La Marque avec l’étude des paramètres physico-chimiques (O2, pH, conductivité, MES, COD), des nutriments (NO3-, NH4+, PO43-), des micropolluants métalliques (Cu, Pb, Zn) et organiques (CAF, CBZ) et des conditions physiques (débit, pluviométrie). Les points clés mis en évidence sont les suivants : (1) La Marque est fortement impactée par le rejet d’eaux usées non traitées dû à des défaillances dans les réseaux d’assainissement ; (2) la station d’épuration contribue significativement à enrichir La Marque en CBZ et en Zn, ce qui participe vis-à-vis de ce dernier à la dégradation de l’état écologique ; (3) la capacité de traitement par décantation et processus biogéochimiques naturels du lac du Héron est efficace, cependant il est nécessaire d’entreprendre un curage du chenal d’entrée ; et (4) le rejet du lac participe à améliorer ponctuellement mais faiblement la qualité de la rivière, excepté lors d’évènements particuliers. / The Marque River is a little watercourse located in a peri-urban watershed in Northern France, going through agricultural and urban areas. Nearby Villeneuve d’Ascq, this river receives waters from two main water treatment plants: (i) the waste water treatment plant of Villeneuve d’Ascq; and (ii) the waters from a stormwater basin, the Heron lake. In order to improve the understanding of the functioning of the river in this area, low and high frequencies monitoring have been undertaken in 2014. In addition, an instrumented buoy belonging to the French Water Agency Artois-Picardie was implemented in 2015 on the lake. A multi-tracers approach was considered in order to identify different pressures on The Marque River including physicochemical parameters (O2, pH, conductivity, SPM, DOC), nutrients (NO3-, NH4+, PO43-), trace metals (Cu, Pb, Zn), organic micro-pollutants (CAF, CBZ) and hydrodynamic conditions (water flow, rainfall). The key points that have been highlighted are as follows: (i) The Marque River is strongly impacted by the discharge of wastewaters, due to sanitation network failures; (ii) the waste water treatment plant contributes significantly to the enrichment of The Marque River in CBZ and Zn, the latter participating to the degradation of the ecological status; (iii) the treatment capacity by naturals settling and biogeochemical processes is efficient within the Heron lake. However, the dredging of the entrance channel must be undertaken; and (iv) the discharge from the lake to the river tends to ameliorate scarcely and punctually the water quality of the river, excepted during special events.

La dégradation photocatalytique de deux amines, la méthylamine (MA) et la diméthylamine (DMA), a été étudiée en présence de TiO2 Degussa P25. Différents paramètres ont été étudiés: l'adsorption à l’obscurité et sous UV, la photolyse, les cinétiques de dégradation, l'effet du pH, l'effet de la nature et de l'intensité du flux photonique ainsi que les voies de dégradation de la MA et DMA.A l’obscurité, le taux de recouvrement des groupes OH est similaire pour la MA et DMA. Sous UV, ce taux devient deux fois plus élevé pour la MA. Les réactivités de MA et DMA sont directement corrélées à leur adsorption sous UV. Les atomes d'azote sont principalement décomposés en ammonium. Le nitrite a été également détecté, mais rapidement oxydé en nitrate. À pH basique, l'hydrolyse photo‐assisté et l'attaque de OH• sur l’atome N augmente. DMA est essentiellement transformé en MA. Les analyses du Carbone Organique Total (COT) montrent la présence de produits finaux contenant de l’azote difficilement minéralisables. Nous avons montré que, quelle que soit l'énergie des photons (UV‐A ou UV‐B), le rendement quantique reste constant et égal à 0,033.L'inactivation photocatalytique de E. coli en présence de la lumière solaire naturelle en absence (SODIS) et en présence de différents catalyseurs a été étudiée. L'effet de la température sur l'inactivation de E. coli a été aussi étudié. Les résultats ont montré que l’addition des différents types de catalyseurs accélère l'effet bactéricide du rayonnement solaire. Aucun phénomène de reviviscence bactérien n’a été observé après l'arrêt de l'exposition solaire durant au moins 72 heures. Seulement les ions ammonium et potassium ont été détectés au cours de l'inactivation de E. coli en accord avec la perforation de la membrane et l’oxydation des protéines. / The photocatalytic degradation of two amino‐compounds, methylamine (MA) and dimethylamine (DMA) was investigated in the presence of UV‐irradiated TiO2 aqueous suspensions. Different parameters were studied: adsorption under dark and UV conditions, photolysis, kinetics of degradation, effect of pH, effect of the nature and intensities of photonic flux and finally the chemical pathway MA and DMA degradation.While, the percentage of covered OH in the dark was equal for MA and DMA, it becomes twice higher for MA under UV. The reactivity of MA and DMA is directly correlated with the adsorption under UV. The nitrogen atoms were decomposed mainly to ammonium. Nitrite was also formed but was rapidly oxidized to nitrate. At basic pH, photo assisted hydrolysis and the attack of OH• on N‐atom increase. DMA is mainly transformed to MA. Total Organic Carbon (TOC) analysis show the presence of final slightly mineralised intermediate compounds containing nitrogen atom. We shown that, whatever the energy of photons (UV‐A or UV‐B), the same quantum yield equal to 0.033 was obtained.The photocatalytic inactivation of E. coli under natural solar irradiation in the absence (SODIS) as well in the presence of different concentrations of varied photocatalysts has also been investigated. The effect of temperature on E. coli inactivation was studied. Results show that the additions of any types of catalyst to the water accelerate the bactericidal action of solar irradiation and leads to a total disinfection. No bacterial regrowth was observed during the subsequent dark period. Ammonium and potassium ions were formed during E. coli inactivation in agreement with the membrane perforation and the oxidation of proteins.