Microorganisms that cause plant disease have been isolated in recirculated irrigation water and increase the risks of disease incidence in horticultural operations. Ozone is an effective oxidizer used to disinfect drinking water supplies and treat industrial wastewater. The objective of this research was to investigate using ozone gas as part of a strategy to reduce the incidence of Phytophthora deBary in recirculated irrigation water. An isolate of Phytophthora capsici Leonian was cultured to induce sporulation. Spore dilutions were placed in aliquots of reverse osmosis water and bubbled with ozone gas (O3) to concentrations of 0 to 1.5 mg·L-1. Ozonated samples were plated and observed for colony forming units. Increasing ozone concentrations reduced the number of colony forming units to 0 at 1.5 mg· L-1 03. Turbidity effects on efficacy on Phytophthora capsici were tested using bentonite clay at 0 to 2.0 nephelometric turbidity units and ozone concentrations of 0 to 1.5 mg· L-1. Increasing bentonite did not affect the efficacy of increasing ozone concentrations on reducing colony formation to 0 at 1.5 mg·L-1 O3. Bioassays using Phytophthora capsici on Capsicum annuum L. seedlings confirmed apparent pathogenicity. Reverse osmosis water, containing a soluble fertilizer at 0 to 300 mg· L-1 N, was ozonated to concentrations of 0 to 1.5 mg·L-1 O3 and used to irrigate Chrysanthemum x morifolium T. de Romatuelle. Increasing ozone concentrations did not interact with increasing fertilizer levels to affect the final growth parameters. Chrysanthemum exposed to ozone gas concentrations of 0.5 to 1.5 mg·L-1 showed symptomatic ozone damage. Complete soluble fertilizer solutions with micronutrients were ozonated from 0 to 1.5 mg·L-1 O3 and analysed for nutrient content. Increasing ozone levels did not interact with fertilizers to affect macronutrients. Increasing ozone interacted with iron at a high fertilizer level. Ozone did not affect the efficacy of paclobutralzol in controlling growth in Viola x wittrockiana. Ozone was effective in controlling Phytophthora capsici in recirculated irrigation water with minimum impact on plant growth. Adjustments in fertility regiemes may be needed to counteract the oxidizing affect of ozone on micronutrients.

Thesis (Ph. D)--Ohio State University, 2002. / Title from first page of PDF file. Document formatted into pages; contains xxii, 119 p.: ill. Includes abstract and vita. Advisor: Harold W. Walker, Civil Engineering Program. Includes bibliographical references (p. 115-119).

No description available.

Horizontal Roughing Filtration (HRF) is a pretreatment method used to remove excess turbidity and suspended solids of surface water fed into Slow Sand Filtration units, as these can only operate satisfactorily when the concentration suspended solids is below 25 mg/1 . A critical review and discussion of current pretreatment methods, HRF research and important filtration variables are presented together with a review of mathematical models of sand and roughing filters based on clarification and trajectory theories. A detailed historical review of head—loss theories, their development and adoption in multimedia filtration is given. I. Preliminary results from studies on a small scale HRF model suggested that: - A laboratory scale model must be over 1.2 m in length: 1.6 _in turned out to be acceptable. - An outlet chamber should be provided. — Sampling must be carried out in a two dimensional field. — Intermittent sampling is adequate. One of the main objectives of this research was to identify the Important variables affecting HRF, among velocity, temperature, particle size, particles density, arrangement of the gravel bed 'Coarse—Medium—Fine (LGF),Coarse/Fine—Fine—Coarse (SGF)§, and the bed depth. II. Experiments were conducted on a 1.6m filter scale model, using Fractional Factorial Design to identify the main variables. These were found to be particles size, velocity, and temperature. III. Further runs, using a suspension of kaolin, produced results which, upon analysis for suspended solids, turbidity, particles count, revealed that the efficiency decreases with increasing temperature and velocity and increases with increasing particles size. IV. Concentration curves along the bed enabled: — The development of the removal rate equation, — Defining the operating parts of the filter at various stages of the filtration, ' — The presence of density currents. V. Efficiency variations with the amounts of accumulated solids were monitored and revealed three main trends: a) Constant efficiency; b) Gradually decreasing efficiency; c) Increasing and then decreasing efficiency. - VI. Tracer tests showed the presence of dead zones, and - short—circuiting with either increased deposits or temperature. VII. Particles size analysis revealed that: a. The effect of velocity or temperature on the grade efficiency affects mainly suspended particles in water smaller than 10 pm and 7 pm for LGF and SGF respectively. For particles of larger diameters, an unknown repulsion phenomenon increasing with temperature rise was observed. b. The main mechanisms responsible for particles removal are sedimentation and hydrodynamic forces.

This thesis presents work that focused on the customised detection and measurement of aluminium (Al) in labile and simple organic speciation in natural waters with particular reference to water treatment. The techniques developed were applied to several alum-based coagulation studies of water from the Myponga reservoir. Experiments examined total Al levels as well as the proportion of Al that was bound to natural organic matter (NOM). / The detection of Al was based upon the electrochemical determination of its complex with the ligand 1, 2-dihydroxyanthraquinone-3-sulphonic acid (DASA). The voltammetry of this complex allows the measurement of low levels of Al (LOD of 10 µg/L). This can be achieved by indirect analysis through oxidation by amperometry of DASA (+0.6V vs Ag/AgCl/KCl at a glassy carbon electrode) or by the reduction of the Al-DASA complex through adsorptive cathodic stripping voltammetry (-1.15V vs Ag/AgCl at a mercury film electrode). / An automated flow injection analysis (FIA-Al) manifold was developed based upon the above detection methods. The manifold utilised a number of switching valves, pumps and reactors under computer control. Reductive Al-DASA chemistry at the mercury film electrode to FIA-Al encountered a number of difficulties which prevented its application to real samples. Oxidative amperometry was successfully applied to probe Al levels during water treatment with coagulation. An instream low-level UV lamp, placed between switching valves, allowed Al speciation to be probed by preferentially irradiating different samples. Two Al fractions were thus determined, labile Al- the DASA reactive fraction without UV treatment, and total Al, the DASA reactive fraction processed semi-automatically with a high degree control of the key reaction conditions leading to good reproducibility. / The Al protocol developed was applied to different coagulation experiments with alum. In these experiments, standard and enhanced coagulation conditions were explored with both jar test apparatus and a coagulation/ flocculation pilot plant. This application of the FIA-Al process to the pilot plant allowed the Al levels in treated water to be determined on-line for a wide range of residual Al. / The application of organic matter characterisation techniques enabled further correlation between the Al speciation as derived by the FIA-Al procedure and the character of NOM that binds most readily with Al. Al speciation observed in this study follows the generalised trends observed in other more complex Al studies. During the treatment process, a proportion of Al exists as complex Al polynuclear species and as Al bound to NOM. After the precipitation/ sedimentation process has removed the majority of NOM and colloidal species, the majority of Al exists as the labile form that is free or bound to simple inorganic ions such as hydroxide, fluoride and sulphate. / Thesis ([PhDBiomedicalScience])--University of South Australia, 2004.

Thesis (Ph. D.)--Lehigh University, 2004. / Includes vita. Includes bibliographical references (leaves 163-171).

Thesis (M.S.)--University of Tennessee, Knoxville, 2004. / Title from title page screen (viewed Sept. 27, 2004). Thesis advisor: Gregory D. Reed. Document formatted into pages (x, 155 p. : ill. (some col.)). Vita. Includes bibliographical references (p. 103-106).

Denna rapport är utförd på uppdrag av företaget Norrvatten vilka driver vattenverket Görvälnverket i Jakobsberg utanför Stockholm. Studien är uppdelad i tre huvudmål. Det första målet innefattar att utföra en analys av befintlig mätdata från en sensor som sitter inuti vattenverket. Data från verket jämfördes med väderdata för att få fram eventuella samband. Information om samband skulle kunna leda till att Norrvatten kan använda sin mätutrustning mer effektivt. I analysen användes MatLab och vissa samband mellan TOC (Total Organic Carbon), nederbörd och vattenstånd kunde ses och tydliga säsongstrender kunde även urskiljas. Det andra målet var att komma med ett förslag på mätsystem för kartläggning av skiktningen i vattnet utanför vattenverket Görvälnverket. Syftet med kartläggningen är att se om det finns behov av ett nytt, djupare, råvattenintag. Det tredje målet var att komma med ett förslag på ett alternativ på ett sensorbaserat varningssystem för förändrad råvattenkvalitet utanför verket. Systemets syfte är att ge information till verket om förhöjda halter av förorenande ämnen. För varningssystem och kartläggning av skiktning användes ett bedömningssystem för att väga olika alternativ till mätsystem mot varandra. Bedömningssystemet bestod av tre urvalsmatriser vilka vägde in hur många parametrar som kunde mätas, hur väl de kunde mätas samt kostnader. Utifrån urvalsmatriserna valdes de mest lämpade alternativen för respektive mätsystem. För att kartlägga skiktningen valdes ett mätsystem bestående av sensorer sittande på befintliga provtagningsledningar vid intagsledningarna i verket. För det sensorbaserade varningssystem valdes ett system med sensorer från företaget PME. Mätsystem är tänkt att placeras på egenbyggd plattform under vattnet. Det placeras sedan runt verket för att mäta olika parametrar.

Behovet av energieffektiva och välfungerande vattenreningssystem är stort, och växer i takt med den ökande befolkningsmängden. Lakvatten bildas då framförallt nederbörd rinner genom deponerat avfall. Problematiken kring lakvattenrening består i att bassängerna är placerade utomhus, vilket medför låga temperaturer under vinterhalvåret. Då lakvattenrening i huvudsak utförs med biologisk reningsteknik, medför de låga temperaturerna en sänkning i den bakteriella aktiviteten vilket försämrar reningseffektiviteten. Ett annat problem som ofta uppstår vid lakvattenrening är att det förorenade vattnet ofta består av höga halter kväve, medan fosforhalterna är låga. Detta ger en obalans i bakteriernas metabolism och kan leda till begränsningar i reningseffektivitet. I detta arbete har en nyutvecklad bioreaktor, som testas på Djupdalens avfallsanläggning, undersökts. Bioreaktorn togs i drift under hösten 2015 samt från april – december 2016. Mätdata från Djupdalen baserat på månatliga vattenprover och kemiska analyser för 2014 – 2016, har studerats för att ta reda på bioreaktorns bidrag till reningseffektvitet av ammoniumkväve. Egna vattenprovtagningar har utförts under maj 2017, där reningseffektivitet och aktiv biofilmsyta vid driftsättning av bioreaktorn studerats. Slutligen utfördes försök där biofilm från Djupdalen testats vid 17 – 18 liksom 12 – 15 ˚C med olika halter fosfortillskott, för att undersöka huruvida reningseffektiviteten kan förbättras om fosforhalten höjs. Resultaten tyder på att bioreaktorn bidrar till kraftig förbättring av reningseffektiviteten i luftningsbassängen, men förbättringspotential finns. Flera av de miljömässiga faktorerna i luftningsbassängen medför mindre gynnsamma förhållanden för den bakteriella tillväxten, såsom temperaturer under 15 ˚C, kraftiga underskott av fosfor i det inkommande lakvattnet och något för basiska pH värden. Genom egna vattenprovtagningar och medföljande kemiska analys framkom det att temperaturer över 15 ˚C i lakvattnet gynnar en snabbare utveckling av biofilmen. Slutligen visade laborativa försök att fosfortillskott vid temperaturer på 12 - 15 ˚C medförde en ökad reningseffektivitet, medan resultatet var oförändrat för temperaturer på 17 – 18 ˚C vid en uppehållstid på 24 timmar. Däremot visar en lägre uppehållstid på 16 timmar, att fosfortillskott påverkar försöken positivt för båda temperaturerna. Detta tyder på att ett fosfortillskott under hösten i luftningsbassängen, när temperaturerna i lakvattnet går under 15 ˚C, bör kunna medföra att bioreaktorn kan förbättra sin reningseffektivitet, trots den sjunkande lakvattentemperaturen. / The need for energy efficient and well-functioning water treatment systems is high, and grows as the growing population increases. Leachate is formed as water flows through landfilled waste. The problem of leachate treatment is that the reactors are located outdoors, which causes low temperatures during the winter months. As the leachate treatment is mainly carried out with biological purification techniques, the low temperatures cause a decrease in bacterial activity, which reduces the purification efficiency. Another problem that often arises in this type of water treatment is that the contaminated water consists of high nitrogen levels, while phosphorus levels are low. This gives an imbalance in the metabolism of the bacteria and can lead to limitations in purification efficiency. In this work, a newly developed bioreactor, which is tested at Djupdalen's waste facility, has been investigated. The bioreactor was put into operation in autumn 2015 and from April to December 2016. Measurement data from Djupdalen based on monthly water samples and chemical analyzes for 2014-2016 have been studied to find out the bioreactor's contribution to the purification efficiency of ammonium nitrogen. Water sampling was carried out in May 2017, where purification efficiency and active biofilm surface were calculated during the operation start of the bioreactor. Finally, experiments were performed where biofilms from Djupdalen were tested at 17-18 as well as 12-15 ° C with different levels of phosphorus supplementation, to investigate whether purification efficiency could be improved if phosphorus levels were increased. The results indicate that the bioreactor contributes to a significant improvement in the purification efficiency of the aeration reactor, but there is still an improvement potential. Several of the environmental factors in the aeration reactor cause less favorable conditions for bacterial growth, such as temperatures below 15 ˚C, severe phosphorus deficiency in the incoming leachate and slightly for basic pH values. Through water sampling and the accompanying chemical analysis it was found that temperatures above 15 ˚C in the leachate favor a faster development of the biofilm. Finally, laboratory experiments showed that phosphorus additions at temperatures of 12-15 ° C resulted in increased purification efficiency, while the result was unchanged for temperatures of 17-18 ° C at a water residence time at 24 hours. However, at a lower water residence time of 16 hours, the phosphorous supplement gave an effect for both temperatures. This indicates that a phosphorus supplement during the autumn of the aeration reactor, when the temperatures in the leachate go below 15 ˚C, should allow the bioreactor to improve its purification efficiency despite the sinking water temperature.

Dissolved organic nitrogen (DON) in water and wastewater is a major public concern. In drinking water treatment plants (WTP), DON and biodegradable DON (BDON) may form carcinogenic by-products during disinfection and might also serve as a nutrient for microbiological growth in distribution systems. BDON in treated wastewater can promote algal growth in receiving water bodies. Understanding biodegradability of DON is important to develop strategies and processes capable of minimizing DON impact on the wastewater effluent receiving water bodies and drinking water. WTPs are nutrient-poor oligotrophic systems that receive source water with DON of about ≤2 mg N/L. Wastewater treatment plants (WWTPs) are nutrient-rich eutrophic systems which receive raw wastewater with DON of ≥8 mg N/L. At WWTPs, sidestream deammonification is a highly eutrophic system employed to treat highly concentrated streams of DON (≥100 mg N/L) and ammonia (≥1,500 mg N/L) generated from filtrate from anaerobically digested sludge dewatering. DON characteristics including biodegradability for different trophic levels could differ. The main goal of this dissertation is to investigate biodegradability of DON in these oligotrophic and eutrophic systems. Three research tasks were performed. In the first task, a method to measure BDON in oligotrophic systems was developed and applied to determine the fate of BDON along four treatment stages of a WTP with ozonation prior to filtration. Optimum dose of inocula and incubation time were identified for the BDON measurement. The Moorhead WTP, Moorhead, MN on average removed 30% of DON and 68% of BDON. The second task involved investigating the role of four biological wastewater treatment processes in removing DON from eutrophic systems. Nitrification process biodegraded 70, 54, and 57% of DON in influent, primary effluent, and secondary effluent, respectively. Heterotrophic DON removal was less (1.7 to 38%) while denitrification and deammonification did not remove DON. For the third task, BDON biodegradability in highly eutrophic system was investigated using nitrifying sludge. About 45 to 90% of DON in sidestream effluent was biodegradable. Information from this dissertation provides a better understanding on DON and BDON fate through water and wastewater treatment processes representing different trophic levels. / District of Columbia Water and Sewer Authority (DC WASA) / Department of Civil and Environmental Engineering, North Dakota State University