The quality of drinking water effects not only human health, but also plays a decisive role in daily life. Although the Taiwan water corporation has improved water quality of Kaohsiung in recent years and most of the random testing results of the drinking water done by the EPB could meet the drinking water standards, many people still lack confidence in the tap water. This study (1) select 500 multi-unit residences from 11 districts in Kaohsiung and survey the water quality of the indirect water supply storage devices to understand the tap water quality of indirect water distribution network in Kaohsiung. (2) Aiming at the inhabitants living in multi-unit residences, a questionnaire about the satisfaction with the tap water in Kaohsiung is undergone by random sampling in order to understand the satisfaction with the tap water of the public. (3) The monitoring values of total trihalomethanes (TTHMs) in tap water distributional network in four seasons from December 2006 to September 2007 are used to analysis the seasonal changes, the equal concentration distribution figure, and the ration of all kinds of compounds of the THMs to the total amounts. The results of above analyses can be offered to Taiwan Water Corporation to make improvement and as the references of following studies. The result of the survey of satisfaction shows that 47% people incline to use tap water as drinking water¡F53% people don¡¦t have confidence in tap water and choose to the bottled water from water stations as drinking water source. 49.1% people living in cluster housing in Kaohsiung consider the quality of tap water common¡F15.4% people are satisfied with the tap water quality and 35.7% people are not satisfied with it. The main reason is the old pipelines, and the secondary reason is about the distasteful water. Most people wish to renew old pipelines as soon as possible, and give priority to strictly control the tap water quality. The analysis result of THMs concentrations shows that the average value of THMs in each district is highest in spring and lowest in autumn, especially in Cianjhen, Siaogang, and Cijin districts. The THMs concentration distribution of Cianjhen district is higher in the spring and winter. The proportion of CHCl3 (chloroform) to total amount of THMs is the highest in the water supply network, and it is also the major source of THMs.

To improve water quality of drinking water, the Taiwan Water Supply Corp (TWSC) upgraded three water treatment plants (WTP), changing traditional treatment processes into two advanced membrane processes and one advanced ozonation processes in recent years. Membrane water treatment units of the water treatment plant comprise ultrafiltration (UF) and reverse osmosis (RO). And the advanced ozonation water treatment units comprise pellet softening, post-ozonation and biological activated carbon (BAC) adsorption. This study investigated the formation of disinfection byproducts (DBPs), dissolved organic carbon (DOC) and assimilable organic carbon (AOC) at two advanced water treatment plants (ATP) in Kaohsiung City, Taiwan, by implementing a sampling program. The purposes of this study include¡G(1) The evaluation of treatment efficiency of advanced water treatment plants. (2) Application of powdered activated carbon and membrane bioreactor in removing organic compounds in drinking water. TCM was by far the predominant species in the finished water, the average concentration of DPBs in this study at both plants were 13.97¡Ó4.18£gg/L and 21.49¡Ó10.59£gg/L of THMs for plant A and plant B, respectively. However, levels for DPBs compound are low in both plants and lower than the current national drinking water quality standards 80 £gg / L. But for anther typical DPBs (HAAs compounds), the average concentrations were 17.67¡Ó14.50£gg/L and 33.03¡Ó16.24£gg/L of HAA5 for plant A and plant B, respectively. DCAA and TCAA were the two major species of HAAs found in the two water samples under study. The sums of the two species represented in finished water were about 67% and 83% of HAA5 in A and plant B, respectively. The results showed that HAA5 concentration of all samples could meet current USEPA standards for drinking water quality. Importantly, our work show the advanced treatment processes have good removal on DPBs of treated water. In organic compounds removal, there is high efficiency by using post-ozonation combined with BAC, but low efficiency for membrane process due to the inhibition of electrical charge happened on surface of membrane. This inhibition is caused probably by high hardness and high ion strength in water. We found by combining BAC with membrane filtration process will effectively remove the organic compounds and lower the concentration of AOC for passing the limit value suggested in related researches of the world.

Water treatment facilities have been relying on indicator bacteria to assess the quality of water for decades. The purpose of this group of studies is to investigate the predictive capabilities of conventional and alternative indicators for pathogenic microorganisms in disinfection processes and treated wastewater effluents. In addition, the possibility that diversity of indicator bacteria, as well as overall bacterial diversity, correlate with fecal contamination in water bodies has been investigated. Indicator organisms (total coliforms, fecal coliforms, enterococci, C. perfringens, and coliphages) as well as pathogens (enteroviruses, Giardia, and Cryptosporidium) were enumerated from six wastewater treatment facilities at various stages of treatment. Statistical analyses were conducted to determine if the indicator organisms (individually or as a set) could predict the presence or absence of pathogens. Single indicator organism analysis failed to correlate with the occu rrence pathogens, thus monitoring a suite of indicator organisms may be a better measure to predict the presence of pathogens. The product of chlorine residual concentration and contact time (CT) was identified as a factor for determining the log10 reduction of enteric viruses in wastewater treatment facilities that used chloramines for disinfection.Samples were also collected from river waters and sediments in watersheds with different human population densities to identify the impact of anthropogenic activities on bacterial diversity. 16S rRNA restriction fragment length polymorphism (RFLP), ribotyping, and denaturing gradient gel electrophoresis (DGGE) were used to determine total coliform, Escherichia coli, and bacterial community population structures, respectively. The concentrations of indicator organisms were significantly different among the river sites in sediments, but not in water column. The population diversity measurements were not significantly different among the river sites; while the indicator population and bacterial community structures were dissimilar in water column vs. associated sediment samples. Accumulation curves demonstrated that greater than 20 isolates must be sampled at most of the sites to represent the dominant populations. A better understanding of the relationship between the indicator organisms and pathogens as well as knowledge of the ecology of indicator organisms in pristine and anthropogenically impacted waters may contribute to water quality restoration and public health protection.

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

Limited studies focused on reactions occurring during disinfection and oxidation processes of seawater. The aim of this work was to investigate disinfection by-products (DBPs) formation from the chlorination and chloramination of seawater algal organic matter and related model compounds. Simulated algal blooms directly growing in Red Sea, red tide samples collected during an algal bloom event and Hymenomonas sp. monoculture were studied as algal organic matter sources. Experiments were conducted in synthetic seawater containing bromide ion. A variety of DBPs was formed from the chlorination and chloramination of algal organic matter. Brominated DBPs (bromoform, DBAA, DBAN and DBAcAm) were the dominant species. Iodinated DBPs (CIAcAm and iodinated THMs) were detected, which are known to be highly toxic compared to their chlorinated or brominated analogues. Algal organic matter was found to incorporate important precursors of nitrogenous DBPs (N-DBPs), which have been reported to be more toxic than regulated THMs and HAAs. Isotopically-labeled monochloramine (15N- NH2Cl) was used in order to investigate the nitrogen source in N-DBPs. High formation of N-DBPs was found from Hymenomonas sp. sample in exponential growth phase, which was enriched in nitrogen-containing organic compounds. High inorganic nitrogen incorporation was found from the algal samples enriched in humic-like compounds. HAcAms formation was studied from chlorination and chloramination of amino acids. Asparagine, aspartic acid and other amino acids with an aromatic structure were found to be important precursors of HAcAms and DCAN. Factors affecting HAcAms formation (Cl2/ amino acid molar ratio and pH) were evaluated. Studies on the formation kinetics of DCAcAm and DCAN from asparagine suggested a rapid formation of DCAcAm from organic nitrogen (amide group) and a slower incorporation of inorganic nitrogen coming from monochloramine to form DCAN. High amounts of DCAN and DCAcAm were detected from the chloramination of aromatic compounds (i.e., phenol and resorcinol) indicating that N-DBPs can also be formed from organic compounds without any organic nitrogen through the incorporation of inorganic nitrogen from monochloramine. Moreover, results from Hymenomonas sp., aromatic amino acids, and phenolic compounds suggested that aromatic compounds are highly reactive with monochloramine and a major fraction of DBP precursors.

Microbes survive for an extended period of time on fomites. With new strains of pathogens constantly emerging, it is important to understand their survival and spread and to evaluate the efficiency of new disinfection methods. The purpose of this study was to determine the occurrence of pathogens on fomites, and evaluate different disinfection methods (household bleach and steam vapor). Fomites were sampled in a variety of environments for the presence of pathogens including methicillin intermediate- and resistant- Staphylococcus aureus, Clostridium difficile, Penecillium brevi-compactum, Alternaria alternata and novel H1N1 influenza A. Samples were assayed using both cultural and genetic techniques to determine the microbial occurrence. In disinfection studies, samples were collected before and after disinfectant application. Steam vapor was effective at reducing microbial occurrence by>90% with a minimal contact time of 10-20 seconds on hospital fomites. The material and shape of the surface had an effect on the reduction rate, due to access of the disinfecting agent. In addition, low levels of initial contamination limited the reduction rate. Many surfaces had a starting contamination level of less than 3 log10 and after disinfection the contamination levels, in 69% of the samples, were at or near the limit of detection. This suggests a higher reduction is feasible. Household bleach reduced the presence of mold spores and mycelium by >99% on gypsum-wall board. Reduction rates were influenced by the growth stage of mold, with the mycelium requiring additional disinfectant application to achieve the 99% reduction rate. Novel H1N1 influenza A was not recovered on any surfaces in day care facilities and elementary schools. This is consistent with previous studies looking at H1N1 influenza occurrence in similar environments, though it is different from H3N2 influenza A studies. Survival differences among varying influenza strains are expected to have an impact on pathogen spread and human health risks. Differences can be quantitatively evaluated and used to develop more advanced risk assessment models. Steam vapor and household bleach are effective at reducing risks of pathogens in the environment and are critical interventions in an overall strategy to minimize exposure and prevent disease.

The problem of the research: The analysis of commercial activity helps to get to know better the market and factors, which predetermine its changes. This allows to prepare more effective plan of company’s activity and to protect leaders from incorrect decisions. Trying to accomplish theoretical factors of commercial activities analysis practicing, the market of JSC “Agrokonsultos group” was chosen. This company resells disinfection materials. The decision was predetermined also by the thing, that despite the market of disinfection materials is small, it is very important and there is not so much information about it. The purpose of the research – to analyze the commercial activity of cattle-breeding company, to evaluate the tendency of resold disinfection materials consumption. Tasks: 1. to analyze and systematize academic literature related with company’s activity; 2. to get acquainted with JCS “Agrokonsultos group” activity; 3. to analyze commercial activity of this company; 4. to discuss the demand’s and supply’s of resold disinfection materials; 5. to find out the main factors, which influence the supply and demand of disinfection materials; 6. to give conclusions. Results: After analyzing JSC “Agrokonsultos group” commercial activity it was established, that the most profitable market are large cattle-breeding complexes, which can buy large amounts of disinfection materials. There also can be direct contracts or simple permanent orders. When the analysis of... [to full text]

Issues of Disinfection By-Product (DBP) formation in response to chlorination in drinking water treatment systems is a common issue encountered by WTP operators. Efforts to minimize DBP formation are complicated by the presence of zebra mussels, which may inhabit the raw water intake of WTPs. While chlorination at the intake to control zebra mussel populations is effective, the formation of DBPs is exacerbated. Methods for reducing DBPs are explored, including adjusting the location for chlorine additions in the treatment sequence. Multivariate models for Total Trihalomethane (TTHM) and Haloacetic Acid (HAA) subspecies are employed to show that in some instances pre-chlorination can be reduced to lower DBP formation, while post-chlorination can be increased. A Regression model (R2 of 0.75) predicts that DBP levels can be lowered by post-chlorination rather than pre-chlorinating raw water for portions of the year except during the combatable life stage to assist in zebra mussel control. A second multivariate regression model for TTHM (R2 = 0.91) which includes bromide, a variable which, due to lack of data, was previously unused, is described and demonstrates that DBP levels can be reduced by lowering pre-chlorination levels. Finally, a Bayesian network is developed using the Webweavr-IV Toolkit, utilizing causal relationships between raw water quality parameters in the form of conditional probabilities. The results show that the average cancer risk can be decreased by while still maintaining zebra mussel control and simultaneously decreasing the incremental cancer risk, which currently fluctuates between 1 in 50,000 to 100,000 in Ontario. / Canada Research Chair Program, Ontario Research Foundation

This study showed that hydrodynamic particle breakage had potential as a method to help improve the disinfection of wastewater effluents. The physicochemical properties of flocs from four distinct effluents sources (combined sewer overflow, settled combined sewer overflow, primary effluent, and final effluent) were compared before and after hydrodynamic treatment. The use of hydrodynamic force to cause floc breakage was shown to be effective, though variable, across all source types. This variation in floc breakage did not have a significant impact on the UV disinfection achieved, as the UV dose kinetics were similar across samples from the same source type. The results of this study demonstrate how the physicochemical properties of floc are affected when exposed to shear force. These observations further the understanding of floc composition and behaviour when shear forces are applied while also providing evidence to indicate this process improves the performance of UV disinfection technology.

Natural organic matter (NOM) is present in all surface waters as a result of decaying vegetation, biological activity, and organic soil. Alternative NOM removal processes such as anion exchange resins (AERs) have shown NOM removals typically ranging between 50 to 90%, with up to 99% removal achieved in some cases. The first portion of this study evaluated the performance of two AERs; a conventional Type 1 AER and magnetic ion exchange resin (i.e. MIEX®) for NOM removal from surface water quantified by UV254, dissolved organic carbon (DOC), and specific UV absorbance (SUVA). Samples were also characterized for chloride, sulphate, and chloride-to-sulphate mass ratio (CSMR) to provide additional information on water quality characteristics of AER treated waters. Overall, the results showed that both AERS were effective for removing NOM. However, the MIEX® resin provided greater removal of NOM with shorter contact times compared to the conventional resin investigated. Water treated with MIEX® resin showed significantly higher chloride and lower sulphate concentrations than the conventional AER. Higher CSMR values were found with MIEX® treated water compared to conventional AER system, although both resins showed CSMR much greater than 0.5, which can increase galvanic corrosion effects with lead. Bench-scale jar tests were conducted to investigate the impact of temperature on the efficacy of three NOM removal treatment technologies; enhanced coagulation with alum, MIEX® and a combined MIEX® treatment followed by coagulation with a low dose of alum. Higher settled water turbidity was observed during cold water operating conditions for all three processes. At cold-water operating conditions, DOC removal was reduced with combined MIEX® -Alum treatment, and UV254 removal was impacted for both MIEX® and MIEX® -Alum processes. The combined MIEX®-Alum process was found to provide the lowest THMFP and HAAFP at both temperatures to concentrations lower than current regulatory maximum acceptable concentration (MAC) guidelines in Canada. Surface charge analysis experiments were performed at bench-scale using synthetic water containing humic acid to determine the relationship between NOM and the charge of AER-treated waters. Further bench and pilot-scale studies were performed to investigate the use of surface charge measurements to monitor and optimize NOM removal during treatment with AER systems. Strong correlations were observed between UV254 and respective charge measurements (i.e. ZP, SC) of AER-treated synthetic and raw waters. The results of this research has shown that it is possible to use charge to optimize the MIEX® process for NOM removal. Additionally, it was found that SC measurements could be used as an operational tool for AER processes, where deviations in SC from optimum treatment would indicate the requirement for fresh resin addition or resin regeneration.