Based on many years of water quality (including algal) and water treatment cost data, available at Umgeni Water, a study was undertaken to better understand the water quality relationships in man made lakes within the company's operational area, and to investigate how water quality affected the cost of treating water from these lakes. The broad aims to the study were to: identify the key environmental variables that were affecting algal populations in lakes; and if these were significant to establish predictive models relating algae to the water quality; and to develop models relating the water quality in lakes to the cost of treating water from the lakes. Semi-quantitative models were developed relating algal abundances with important environmental variables. In most cases, the models developed were related to algal populations that were known to adversely affect water treatment. Direct algal impact on water treatment processes was through the production of either taste and odour forming compounds (requiring advanced water treatment, such as use of activated carbon), or their ability to clog sand filters and so reduce filter run times (requiring more frequent backwashing of filters). Thereafter lake water quality parameters (which included water physico-chemistry and algae) were investigated to determine which factors were most significantly impacting on water treatment and hence treatment costs at selected water works (WW) within the Umgeni Water operational area. Models were developed relating raw water quality entering respective water works with costs incurred in treating that water. The models allowed simulations to be developed illustrating how changes in water quality might impact on water treatment costs. The impact of eutrophication and contamination of rivers and lakes, and its subsequent impact on surface water resources, was quantified. / Thesis (Ph.D. (Botany))--North-West University, Potchefstroom Campus, 2004.

Based on many years of water quality (including algal) and water treatment cost data, available at Umgeni Water, a study was undertaken to better understand the water quality relationships in man made lakes within the company's operational area, and to investigate how water quality affected the cost of treating water from these lakes. The broad aims to the study were to: identify the key environmental variables that were affecting algal populations in lakes; and if these were significant to establish predictive models relating algae to the water quality; and to develop models relating the water quality in lakes to the cost of treating water from the lakes. Semi-quantitative models were developed relating algal abundances with important environmental variables. In most cases, the models developed were related to algal populations that were known to adversely affect water treatment. Direct algal impact on water treatment processes was through the production of either taste and odour forming compounds (requiring advanced water treatment, such as use of activated carbon), or their ability to clog sand filters and so reduce filter run times (requiring more frequent backwashing of filters). Thereafter lake water quality parameters (which included water physico-chemistry and algae) were investigated to determine which factors were most significantly impacting on water treatment and hence treatment costs at selected water works (WW) within the Umgeni Water operational area. Models were developed relating raw water quality entering respective water works with costs incurred in treating that water. The models allowed simulations to be developed illustrating how changes in water quality might impact on water treatment costs. The impact of eutrophication and contamination of rivers and lakes, and its subsequent impact on surface water resources, was quantified. / Thesis (Ph.D. (Botany))--North-West University, Potchefstroom Campus, 2004.

This thesis includes both experimental and modelling studies on the treatment of drinking water. Three aspects were studied: (i) removal of fluoride (F– ) by adsorption, (ii) removal of fluoride and other contaminants by solar distillation, (iii) denitrification by a microbial fuel cell. The availability of potable water on earth is about 0.2% of the total available water. This very small quantity is polluted by anthropogenic and natural contaminants. Fluoride is a classic example of a natural contaminant, wherein the dissolution of F– bearing minerals causes the release of F– into the groundwater. Exposure to concentrations > 1 mg/L over ex-tended periods of time results in dental and skeletal fluorosis. Worldwide, about 220 million people are at risk. Nitrate is an example of anthropogenic contaminant, occurring because of addition of high quantities of fertilizers to the soil for better crop yields. The excess fertilizers penetrate the soil and mix with the groundwater, resulting in nitrate contamination. The major effect of nitrate contamination is met haemoglobin , which is caused because of the oxidation of ferrous ion in haemoglobin to ferric ion by the nitrite to form haemoglobin. The effects can be noticed by the change in colour of skin to bluish grey or brownish grey in infants. To counter the drastic effects of these anions, the World Health Organization (WHO) has prescribed permissible limits of 1.5 mg/L and 45 mg/L for F– and NO3 – , respectively. For obtaining contaminant-free water, many methods have been used. Reverse osmosis (RO) is one of the widely-used methods. Even though this process removes most of the contaminants, about 50 - 70% of the inlet water is wasted as a reject stream with higher concentrations of the contaminants. This is a very unsustainable way of using water, particularly in drought-prone areas. So, in the thesis a conceptual strategy with three different methods is developed to treat reject water. In the first part of the thesis, the removal of F– using adsorption was studied. Activated alumina (AA) and a hybrid anion exchange resin embedded with hydrous zirconium oxide nanoparticles (HAIX-Zr) (sample sent by Prof. Arup K SenGupta) were used as the adsorbents. The adsorbents were tested with synthetic water samples and reverse osmosis (RO) reject water. HAIX-Zr had a better adsorption capacity compared to AA when water containing only F– was used. The presence of high concentrations of co-ions affects the uptake of F– drastically, with a decrease of up to 34% and 79% for AA and HAIX-Zr, respectively. With AA, for a synthetic water sample with a small concentration of HCO3 – , there was a two-fold increase in the uptake of F– compared to a water sample containing only F– . There was no removal of NO3 – by AA. HAIX-Zr removes NO3 – , but to a lesser extent than F– . With AA, the pH of the inlet solution affected the adsorption capacity, because of the change in the surface charge of AA. Based on the type of water sample used, the cost of treated water varied from Re. 0.1 - 1.0/L ($ 0.0015 - 0.015/L) for AA and 0.2 - 11.5/L ($ 0.003 - 0.17/L) for HAIX-Zr. A community-level plant was set up to treat the RO reject water using AA. Due to challenges at the field level, the pilot plant had to be stopped after 80 bed volumes of water were treated. From our observations and as also reported by many authors, the adsorption of F– is affected by the presence of many ions. When modelling the adsorption of F– , it is usually taken as a single entity getting adsorbed on the adsorbent. As this is not a proper assumption, a model was developed which takes into account all the speciation reactions that take place during adsorption, and all the species like H+, OH– , Na+, Cl– , and NO3 – present in the solution along with F– . Using the model, the equilibrium constants and rate constants for the reactions were obtained. For one initial concentration of F– , a good fit was obtained to the batch adsorption data, except at short times. Due to uncertainty about the amount of impurity present in the adsorbent, at higher initial concentrations of F– , there was a significant discrepancy between predictions and data. Considering column experiments, the breakthrough curve for F– was simulated using the developed model. For the special case of negligible mass transfer resistances, the predicted break-through volume was within 3% of the observed value. In the second part of the thesis, nitrate removal was investigated using microbial fuel cell (MFC). In a MFC, power is generated by the activity of the microorganisms present in the cell. The organisms present in the anode side release electrons (e– ) by the use of substances that can be oxidized, namely, glucose, acetate, etc. On the cathode side, the organisms have the potential to take in e– and reducible substances, and release reduced products like nitrogen, hydrogen, etc. In the present case, nitrates added to the cathode side were reduced to nitrogen gas by the use of a consortium of micro-organisms taken from seawater. A similar consortium was used in the anode chamber Here, the study was focused on improving the efficiency of MFC for removal of NO3 – , by changing the buffering medium used in the cells. Commonly, phosphate buffer is used, but when using a MFC for treatment, the presence of PO43 – causes water contamination and is not suitable for drinking. There-fore, PO43 – was replaced with HCO3 – on the cathode side of the cell. This resulted in a higher removal of NO3 – and power production compared to the PO43 – buffered solution In the third part of the thesis, contaminant removal using solar distillation was investigated. For this as inclined basin still was used. Investigations were based on the evaporation rate of contaminated water, and the odour and concentrations of ions in the distillate. In order to improve the evaporation rates, different radiation absorbing materials like sand, activated charcoal, and carbon nanoparticles encapsulated in polymer sheets (PCNP) were investigated. It was observed that the evaporation rates were higher with activated carbon than the other materials. Using this technique there was about 99% removal of NO3 – , F– , SO42 – and the concentrations of ions in the distillate were well below the acceptable limits. When sand or PCNP was used as an absorbing/wicking medium, the distillate had an objectionable odour. With the use of AC, the odour could be eliminated because of the adsorption of odour-causing compounds.

Diploma thesis deals with assessing of effectiveness removing pecticides of reconstructed water treatment plant. In the introduction ismade a short research focused on pesticides, their getting into sources of drinking water and possibilities their removing by water supply processes. As part of this work are assessed effectiveness of this processes for removing pesticidal substances on specific water treatment plant and its sources of drinking water. Is made description of technology water treatment plant before and after the reconstruction, measured data of concetration pesticides in the sources and in the output from water treatment plant is processed to the tables and to the graphs. In conclusion are assessed effectiveness of the new technology for removing selected pesticidal substances and their metabolites.

This study deals with a reconstruction of the water treatment plant. The First chapter gives a brief overview of iron and manganese common removal methods. The next chapter looks at technical condition evaluation of urban water networks and presents a new methodology TEA Water developed by Brno University of Technology, module TEAT-Water Treatment Plants in particular. Following chapters describes local water distribution system and current condition of the water treatment plant. The main aim of this thesis is to choose the best suitable technologies for water treatment in order to reduce high operating expenses, especially energy consumption and to reduce volume of backwash water.

Microbial Fuel Cell is a novel technology that can be used for a waste water treatment in order to simultaneously remove carbonaceous matter and nitrogen while producing electrical power. Even if it is not an established technology so far, MFC could be a cost effective option for waste water treatment and the major challenge of this process will be the device scale-up. Exoelectrogenic bacteria are capable of converting the chemical energy of organic matter into electrical energy by transferring the electrons produced in the oxidation to the anode electrode. This project focused on developing a single device for nitrification, denitrification and carbon removal. Two double air-cathode single chamber MFCs are used to test the feasibility of this process that could replace the biological unit in a waste water treatment train. The cells tested in this study were manufactured with the purpose of achieving a high surface area on both the anode electrode (vitreous carbon foam) and the air-cathode electrodes (metallic mesh with diffusion layer and active layer) with different catalysts for the reduction reaction (cobalt and platinum). The bacterial biofilm growth is a fundamental step and the cells Open Circuit Potential was monitored during all the start-up period to determine the microorganism acclimation: a three days lag period was observed in both cells before the potential rise. The second cell was forced to reach higher voltage through an anode polarization and that seems to positively affect the biofilm stability at lower voltages transferring a greater amount of electrons and hence obtaining a higher current and power generation. For this reason after three weeks of inoculation the second cell reached an open circuit potential of 0.76 V which is a promising value for such a system. Electrochemical and biological tests were conduced in order to test the power production of the cell and the substrate removal from the waste water. Polarization curves were used to evaluate power generation (and the maximum production under a specific external load) and the cell voltage trend which is characterized by activation and ohmic losses: 32 mW/ and 41 mW/  are the power density normalized by cathode surface (72 ) reached by respectively first and second cell. The experimental conditions were varied from low to high temperature and from low to high inlet flow rate but the most affecting phenomenon seems to be the biofilm formation since significant voltage drops were noticed after long closed circuit operation. Higher cell voltage characterized the second cell thanks to more active cathode (platinum catalyst used) and more negative bacterial biofilm but a bigger drop in current generation over time affects the system performance and the most reliable reason is the shorter acclimation time compared to the first cell. Cyclic voltammetry tests were carried out on both electrodes to study the potential range of activity and determine an optimal operational voltage despite of mass transport or kinetic limitations. Substrate removal tests at different retention times in power generation conditions (external load 100 Ω) showed a relatively high total nitrogen consumption (maximum 72.2 %) for the first cell while lower values were achieved by the second system meaning that a longer acclimation period is beneficial for nitrifying and denitrifying bacteria to thrive on the cathode biofilm. Effluent pH level are almost similar to the initial values probably because of nitrification and denitrification protons offset.

The phenomenon of rapid algal blooms in response to nutrient overloads has been adapted to treat synthetic domestic wastewater. Various algal consortia collected from several eutrophied water bodies were subject to high density algal culture (upto 106-107 cells/mL) and screened for rapid algal growth, pollutant removal, nutrient recovery under mixotrophy and auto-flocculation. When tried in laboratory scale algal ponds, these algal consortia showed growth rates between 0.15 and 1.07 d-1. Results indicate that Chlorella occurred frequently among most consortia although not always the largest in number. While individual algal species varied in growth rates among these consortia, the log phase for most of these algae lasted 4-5 d after which the algal species began to flocculate between day 5-8 at different rates. The flocculation stage lasted between Day 6-8 wherein about 65% cells flocculated during monsoon and over 90% in winter. Although over 90% removal of N and 80% removal of P occurred in this period, the net N and P harvested as flocculated algae ranged from ~30-50% and ~40-70%, respectively. A consortia approach, wherein algal cells auto-flocculate after reaching a high cell density and nutrient removal provides an easy, low energy and sustainable approach to simultaneous wastewater treatment as well as energy and nutrient recovery from domestic wastewaters.

Goal of this research was to recognize dissolved air flotation efficiency by the help of turbidity and UV absorbance removal for different conditions. As different conditions are meant the efficiency for different baffle position, different detention time in separation zone and checking results with adding chemicals compared to results without adding chemicals.

Climate change is a global challenge that requires proactive action from municipalities, companies, and other organizations to prioritize sustainability in their daily operations. In the past few decades, life cycle assessment (LCA) approach has been successfully applied for environmental assessments in the drinking water sector. In this study, this approach has been used to present a comparative evaluation of the potential environmental impacts associated with nine different process alternatives for future drinking water production at Norrvatten. This study is a pioneering one that explores the potential of LCA as a decision support tool to prioritize and optimize environmental impacts during the operational phase in Swedish drinking water production. The nine alternatives are designed for the year 2050 to meet the average daily demand of 208 MLD for the 14 municipalities in the northern Stockholm region that Norrvatten supplies with drinking water. Out of the nine alternatives, the alternative based on direct filtration of raw water on nanofiltration membranes came out as the most environmentally friendly solution due to the use of renewable electricity from hydro and wind power. The results indicate that the potential environmental impacts are dominated by the use of chemicals in all alternatives, which in turn depends on the energy sources used for chemical production that are mostly dominated by fossil-based non-renewable sources. The impacts due to transportation and energy consumption are relatively less in Swedish drinking water production. Moreover, filtration through granulated activated carbon (GAC) is the most environmentally damaging treatment step, but regeneration of saturated GAC induces positive impacts in all alternatives. Among environmental impact categories, categories related to fine particulate matter formation; global warming, human carcinogenic toxicity, and human non-carcinogenic toxicity are the most significant in all alternatives. Several of the treatment technologies included in the nine alternatives, such as Nanofiltration, have only been tested on a pilot scale and have not been used for drinking water production at Norrvatten. So this study should be followed up and supplemented with better representative inventory data relevant to the Swedish context in order to contribute more effectively in making the future Swedish drinking water production more sustainable and environmentally friendly. Also, this study is based on the most recently available data that may not be valid in 2050 and the latest trends to substitute non-renewable energy sources with renewable sources may reduce the impacts due to chemical production and transportation in the future. Moreover, this LCA study does not include any aspects of water quality and treatment costs. Hence, while comparing different alternatives, the quality of the treated water and its production cost must also be taken into account. / Klimatförändringar är en global utmaning som kräver proaktivt agerande från kommuner, företag och andra organisationer för att prioritera hållbarhet i sin dagliga verksamhet. Under de senaste decennierna har livscykelanalys (LCA) använts för miljöbedömningar inom VA-sektorn. I denna studie har detta tillvägagångssätt använts för att presentera en jämförande utvärdering av den potentiella miljöpåverkan som är förknippad med den framtida dricksvattenproduktionen vid Norrvatten. Med hjälp av LCA så jämförs nio olika processalternativ för den framtida produktionen och kan på så sätt bidra till att prioritera och optimera processval utifrån miljösynpunkt. De nio alternativen är utformade för år 2050 för att tillgodose den genomsnittliga dagliga efterfrågan på 208 MLD för de 14 kommuner i norra Stockholmsregionen som Norrvatten försörjer med dricksvatten. Av nio alternativ kom alternativet baserat på direkt filtrering av råvatten på nanofiltreringsmembran som den mest miljövänliga lösningen på grund av användningen av förnybar el från vatten- och vindkraft. Resultaten indikerar att de potentiella miljöeffekterna domineras av användning av kemikalier i samtliga alternativ, vilket i i sin tur beror på de energikällor som används för kemikalieproduktion domineras av fossilbaserade energibärare. Effekterna på grund av transport och energiförbrukning är relativt låg i svensk dricksvattenproduktion. Filtrering genom granulerat aktivt kol (GAC) det mest miljöbelastande behandlingssteget, men regenerering av mättad GAC ger positiva effekter i alla alternativ. Bland kategorier för miljöpåverkan så är kategorier relaterade till bildning av fina partiklar; global uppvärmning, mänsklig cancerframkallande toxicitet och mänsklig icke-cancerogen toxicitet de viktigaste i alla alternativ. Flera av de behandlingstekniker som ingår i de nio alternativen, såsom Nanofiltration, har enbarts testats i pilotskala och inte använts för dricksvattenproduktion vid Norrvatten. Så denna studie bör följas upp och kompletteras med data som är relevanta för förhållanden vid Vättern Denna studie baseras också på tillgängliga data som kanske inte är giltiga 2050 och de senaste trenderna för att ersätta icke förnybara energikällor med förnybara källor som kan minska effekterna på grund av kemisk produktion och transport i framtiden. Dessutom innehåller denna LCA-studie inga aspekter av vattenkvalitet och behandlingskostnader.. Vid jämförelse av olika alternativ måste även kvaliteten på det behandlade vattnet och dess produktionskostnad beaktas.

Os oocistos de Cryptosporidium spp. e os cistos de Giardia spp. podem gerar doenças de veiculação hídrica associadas a problemas de saúde pública. Os (oo)cistos são de difícil remoção e inativação durante o tratamento de água, principalmente devido ao tamanho reduzido e à resistência ao processo de cloração. Além disso, os métodos de detecção de protozoários na água apresentam elevado custo e estão sujeitos à grande variabilidade e à baixa reprodutibilidade, especialmente em águas de elevada turbidez. Com água de estudo com turbidez de aproximadamente 110 uT, ensaios de tratabilidade com cloreto de polialumínio foram feitos em jarteste para a obtenção da água de lavagem dos filtros (ALF) e do resíduo sedimentado. O método escolhido para detecção de (oo)cistos foi a centrifugação direta com adição de solução de dispersão ICN 7X seguido de IMS com duas dissociações ácidas (CD + ICN 7X). O tratamento dos resíduos objetivou a inativação dos (oo)cistos, por meio de danos à estrutura celular dos parasitos, identificada pela incorporação do corante iodeto de propídio no microrganismo. Para o método CD + ICN 7X, menor interferência na viabilidade dos (oo)cistos foi observada em relação à floculação em carbonato de cálcio e melhor recuperação do que a centrifugação direta. O controle de qualidade analítica desse método, feito com suspensão do kit EasySeed®, apresentou recuperação de 2,8±0,8% de oocistos e 7,8±2,9% de cistos para a ALF e de 3,3±2,0% e 24,8±8,0%, para oocistos e cistos no resíduo sedimentado. Apenas a recuperação de cistos de Giardia spp. no resíduo sedimentado atendeu aos padrões recomendados pelo Método 1623.1 da USEPA. A presença de microesferas magnéticas aderidas aos (oo)cistos foi observada nos poços de leitura após a IMS, indicando limitações desse método de purificação. Para o tratamento alcalino do resíduo sedimentado, a dosagem de 27mg/100mL foi testada para os tempos de 3 e 5 dias e, respectivamente, foram obtidos 1,85 e 3,0 log de inativação de oocistos e 2,05 e 2,14 log de inativação para cistos. Para o processo de ozonização da ALF, avaliado apenas para oocistos, as inativações de 2,83 log e 3,44 log foram obtidas para as dosagens de 7,5 mg O3 L-1 por 10 min e 10 mg O3 L-1 por 5 min, respectivamente. / Cryptosporidium spp. oocysts and Giardia spp. cysts are infectious forms and can cause public health problems due to associated waterborne diseases. (Oo)cysts are difficult to remove and inactivate during water treatment, mainly because of reduced size and resistance to chlorination. In addition, protozoan detection methods in water are expensive and subject to high variability and low reproducibility, especially in high turbidity water. In jartest treatability tests, 110 uT study water was treated with polyaluminium chloride to obtain backwashing water (BW) and sedimented residue. The method chosen for detection of (oo)cysts was direct centrifugation with addition of 7X ICN dispersion solution followed by IMS with two acid dissociations. Treatment of residuals objectified inactivation of (oo)cysts by damages on parasites cellular structure, identified by inclusion of propidium iodide as an indicator. The method of detection chosen showed less interference in the viability of (oo)cysts in comparison to flocculation in calcium carbonate and better recovery than direct centrifugation. The analytical quality control of this method, performed with EasySeed® suspension, obtained recovery of 2.8±0.8% oocysts and 7.8±2.9% cysts for BW and of 3.3±2.0% and 24.8±8.0%, for oocysts and cysts in sedimented residue. Only Giardia spp. recovery in sedimented residue complied with the standards recommended by USEPA Method 1623.1. Magnetic microspheres were found attached to (oo)cysts in microscope slides after IMS, indicating limitations of this purification method. For the alkaline treatment of sedimented residue, dosage of 27mg / 100mL was tested for 3 and 5 days and respectively 1.85 and 3.0 log inactivation were obtained for oocysts while 2.05 and 2.14 log of. For ozonation of BW, evaluated only for oocysts, 2.83 log and 3.44 log inactivation were obtained for dosages of 7.5 mg O3 L-1 for 10 min and 10 mg O3 L-1 for 5 min, respectively.