<p>Access to potable water has been identified as a basic human right, yet it is estimated that 2.2 billion people worldwide do not have access to safely managed drinking water. Many of those without access live in regions of the world with abundant sunlight, which can be utilized both directly and indirectly to disinfect drinking water. Directly it can be used in solar water disinfection (SODIS) applications, and indirectly it can be collected by solar panels to power commercially available UV reactors. Herein, we study the potential for direct and indirect water disinfection technologies to be used and adopted in developing countries, with specific insight into their application in the Dominican Republic and Kenya.</p><p>The amount of available ambient solar UV was both measured and modelled to inform design and modelling of treatment systems, and to understand whether real-time monitoring of ambient UV is required for the operation of systems directly utilizing UV for disinfection. The model both over- and under-predicted measurements of ambient UV, and did so at inconsistent rates, most likely as a result of cloud cover. This indicates that real-time monitoring of ambient UV would most likely be needed for disinfection methods directly using solar UV for inactivation in order to ensure water was always dosed properly.</p><p>The amount of available ambient solar UV was input into a raytracing model (Photopia, LTI Optics) to simulate the amplification of solar spectral irradiance within a continuous-flow compound parabolic collector (CPC). This informed design improvements that allowed for an increase in flow rate through the system, which was supported by field testing of the reactor. Further, two commercial UV reactors, one utilizing a low-pressure (LP) lamp and the other utilizing an LED source, were tested in the lab to verify their ability to inactivate <i>S. typhimurium </i>LT2. The LP-based device outperformed the LED-based device, which was unable to achieve over 2-log₁₀ units of inactivation under any of the studied conditions.</p><p>A life cycle assessment was conducted to assess the environmental impact of the three studied UV reactors against traditional chlorination and water delivery methods. Chlorine had the lowest impact in every category under all of the studied conditions, but there have been many barriers reported on the lack of adoption of chlorine. So the next lowest impact technology was evaluated at the community scale, which was the LP reactor. Therefore, the LP reactor was installed in study communities in both the Dominican Republic and Kenya. In the Dominican Republic, the systems suffered from a lack of boots on the ground, and faced technical, social, and economic barriers to adoption. In Kenya, the project suffered from similar constraints, that did not allow for project assessment. This work not only addresses the barriers faced in both of these projects, but provides suggestions for improving similar projects in the future.</p>

A study was conducted to evaluate the sorption characteristics of six disinfection byproducts (DBPs) on four sorbents. To investigate sorption of volatile organic compounds (VOCs), specially designed experimental batch and continuous flow modules were developed. The investigated compounds included: chloroform, 1,2-dichloroethane (DCE), trichloroethylene (TCE), bromodichloromethane (BDCM), methyl tertiary butyl ether (MTBE), bromate and bromide ions. Sorbents used included light weight aggregate (LWA), an inorganic porous material with unique surface characteristics, Amberlite® XAD-16, a weakly basic anion exchange resin, Amberjet®, a strongly basic anion exchange resin, and granular activated carbon (GAC). Batch experiments were conducted on spiked Milli-Q® and lake water matrices. Results indicate considerable sorption of TCE (68.9%), slight sorption of bromate ions (19%) and no appreciable sorption for the other test compounds on LWA. The sorption of TCE increased to 75.3% in experiments utilizing smaller LWA particle size. LWA could be a viable medium for removal of TCE from contaminated surface or groundwater sites. Amberlite® was found unsuitable for use due to its physical characteristics, and its inability to efficiently remove any of the test compounds. Amberjet® showed an excellent ability to remove the inorganic anions (>99%), and BDCM (96.9%) from aqueous solutions but with considerable elevation of pH. Continuous flow experiments evaluated GAC and Amberjet® with spiked Milli-Q® and tap water matrices. The tested organic compounds were sorbed in the order of their hydrophobicity. Slight elevation of pH was observed during continuous flow experiments, making Amberjet® a viable option for removal of BDCM, bromate and bromide ions from water. The continuous flow experiments showed that GAC is an excellent medium for removal of the tested VOCs and bromate ion. Each of the test compounds showed different breakthrough and saturation points. The unique design of the continuous flow apparatus used in the study proved to be highly beneficial to assess removal of volatile organic compounds from aqueous solutions.

Wastewater treatment is essential to protecting the environment and human welfare. Although chlorination is widely used, the environmental and health concerns associated with chlorine are growing. Treatment facilities are implementing alternative technologies, though the cost and efficiency associated with these practices leave much room in the wastewater field for innovation. Hydropath Technologies Limited introduced a piece of equipment that uses the properties of a transformer to pass an alternating electric current through the pipe and into the contents of the channel. Hydroflow claims that the charged microorganisms react with the oppositely charged water molecule to force osmosis and kill the cell. Disinfection capabilities of three Hydroflow models with varying voltages are tested using municipal wastewater from the secondary clarifier using Escherichia coli concentration as the unit for quantification. After testing the results surrounding theses experiments cannot support the hypothesis that the Hydroflow technology could replace chlorination for municipal wastewater disinfection.

Submitted in fulfillment of the requirements for the degree of Master of Technology: Emergency Medical Care, Durban University of Technology, Durban, South Africa, 2013. / Background In the Emergency Medical Services (EMS), paramedics play a vital role in the treatment of critically ill or injured patients, as they are often the first link or point of contact for the patient in the healthcare setting. They may therefore also play a vital role in the prevention and control of the transmission of communicable diseases, provided that proper infection control measures are in place. The objectives of the study There is presently no national policy on communicable diseases and infection control that is specifically designed for use in the South African prehospital environment. Given the paucity of research in the area, qualitative multiple case studies were conducted to develop an ambulance specific disinfection protocol and to evaluate its effectiveness in the public sector EMS in the eThekwini District of KwaZulu-Natal. Methodology The study comprised of three phases. In the first phase focus group discussions were conducted to identify the factors needed to develop a disinfection protocol. The study population consisted of both operational and management staff from the EMS under study. The first four focus groups consisted of eight to ten EMS operational staff each and the fifth focus group consisted of five EMS management staff. Thereafter, the information gathered was used in conjunction with internationally accepted guidelines to develop an ambulance specific disinfection protocol (Phase Two). The third phase entailed the implementation of the protocol at seven ambulance bases in the eThekwini health district and the evaluation of the protocol with the use of an open-ended questionnaire at two weeks and four weeks after implementation. A single ambulance crew and their immediate supervisor from each base were utilized in this phase. Conclusion and recommendations An ambulance specific disinfection protocol was developed and implemented in the EMS under study. During the development, implementation and evaluation of the protocol, many themes with regard to infection control in EMS were identified. These themes were used to better understand the present situation in EMS in relation to infection control and in the formulation of recommendations to assist in the improvement of the present situation. The researcher recommended that all EMS staff require training and education with regard to infection control and prevention. The development and implementation of a protocol and policy document for infection control specifically for EMS is required. There is a need for the deployment of more ambulances and the employment of more operational EMS staff together with the appointment of Infection Control Supervisors at all ambulance bases. Without adequate infrastructure needed to meet infection control and prevention requirements, there may be a serious risk to both staff and the patients they serve. / M

Το πρόβληµα της διαχείρισης των ιατρικών αποβλήτων και ιδιαίτερα αυτών που χαρακτηρίζονται ως επικίνδυνα έχει οξυνθεί τα τελευταία χρόνια στην Ελλάδα. Το 10-25% των παραγόμενων ιατρικών αποβλήτων στις υγειονομικές μονάδες, θεωρούνται επικίνδυνα, με δυνατότητα πρόκλησης μίας σειράς κινδύνων για την υγεία, σε περίπτωση επαφής ή έκθεσης σε αυτά, διότι αποτελούν στις περισσότερες των περιπτώσεων φορείς παθογόνων µικροοργανισµών µε αποτέλεσµα η µη ασφαλής διάθεσή τους να εγκυμονεί σηµαντικότατους κινδύνους, όχι µόνο για το περιβάλλον, αλλά και για τη δηµόσια υγεία. Αντικείμενο της παρούσας εργασίας αποτελεί η μελέτη και η αξιολόγηση μεθόδων επεξεργασίας των επικίνδυνων ιατρικών απορριμμάτων. Ο όρος αξιολόγηση αναφέρεται στην διαδικασία επιλογής της κατάλληλης τεχνολογίας επεξεργασίας, λαμβάνοντας υπόψιν πληθώρα παραγόντων. Οι πιο διαδεδομένες μέθοδοι που θα εξεταστούν, είναι η αποτέφρωση, η αποστείρωση, η απολύμανση με μικροκύματα και η χημική απολύμανση. Σκοπός της εργασίας είναι να καταστήσει σαφές το ότι καμία μέθοδος δεν αποτελεί πανάκεια. Αντιθέτως, πρέπει να γίνεται προσεκτική επιλογή της μεθόδου, πάντα με σεβασμό στην υγεία και το περιβάλλον. / The problem of medical waste management, and especially of that which is characterized as hazardous, has increased in Greece during the last years. Hazardous medical waste is 10-25% of the total quantity of medical waste that is produced in health units. In most cases, this type of medical waste is carrier of pathogenic microorganisms. Thus, its ineffective way of disposal puts in danger the environment and the public health. This thesis is an assessment of different technologies that can manage hazardous medical waste. The term assessment refers to the choice of the appropriate technology, taking into account many different factors. The most widely used methods are incineration, sterilization, disinfection with microwave irradiation and chemical disinfection. Aim of this thesis is to make clear that there is not any technology that is really effective with all types of hazardous medical waste. Thus, we have to carefully choose the appropriate technology, always with respect to health and the environment.

Made available in DSpace on 2014-08-20T14:30:13Z (GMT). No. of bitstreams: 1 Tese_Gloria_Beatriz_Azevedo_Cubas.pdf: 1660996 bytes, checksum: 8bb44113acc263526d63d6f5e7e47e2b (MD5) Previous issue date: 2012-12-07 / The aims of this randomised controlled trial were to evaluate the influence of a preprocedural 0.12% chlorhexidine mouthrinse on the microbial contamination of dental impressions, subsequently disinfected with sodium hypoclorite or water (control). The second objective was to evaluate if aqueous solution of 0.12% chlorhexidine mixed with irreversible hydrocolloid powder would decrease microbial contamination of dental impressions. Forty subjects underwent maxillary dental impressions with irreversible hydrocolloid and were randomly divided into two groups (n=20) according to the preprocedural mouthrinse (0.12% chlorhexidine or placebo).The dental impressions were then divided into two subgroups and disinfected with sodium hypochlorite or water (control). In the second part, 20 subjects underwent maxillary dental impressions with irreversible hydrocolloid and randomly assigned into two groups according to the mixed agent used (0.12% chlorhexidine or water). Saliva and alginate samples were assessed for microbiological counts of total micro-organisms, total streptococci and Candida species. Surface roughness of the impressions and dimensional stability of the casts were also evaluated. Chlorhexidine preprocedural mouthrinse significantly reduced (p<0.05) microbial contamination. Small but significant alterations were produced on dimensional stability and surface quality when sodium hypochlorite was used as disinfectant after the impression (p=0.005). The results also showed that the use of aqueous 0.12% chlorhexidine mixed with the powder of irreversible hydrocolloid decreased the percentage of total micro-organisms and total Streptococci counts (p<0.001), without producing alterations in surface quality and dimensional stability. It can be concluded that 0.12% chlorhexidine used as preprocedural mouthrinse, or mixed with irreversible hydrocolloid powder, are effective methods in reducing microbial contamination of alginate impressions, without causing damage to the physical and mechanical properties of the material / Os objetivos deste ensaio clínico randomizado foram (I) avaliar a influência de um bochecho, com solução de clorexidina 0,12% e placebo, previamente a realização de moldagens bucais, posteriormente desinfetadas com hipoclorito de sódio ou água (controle) na contaminação de moldagens de alginato; e (II) avaliar se solução aquosa de clorexidina 0,12% misturada com o pó de hidrocolóide irreversível reduziria a contaminação microbiana de moldagens bucais.Quarenta voluntários foram submetidos a moldagens bucais com hidrocolóide irreversível e foram divididos de forma randomizada em 2 grupos (n=20) de acordo com a solução bucal (0,12% clorexidina ou placebo). As moldagens bucais foram divididas em 2 grupos e desinfetadas com hipoclorito de sódio ou água (controle). Na segunda parte do ensaio clinico, 20 voluntários foram submetidos a moldagens bucais com hidrocolóide irreversível e foram divididos em 2 grupos de acordo com a solução usada no preparo do alginato (0,12% clorexidina ou água).Amostras de saliva e alginato foram avaliados quanto a contagem microbiana de microrganismos totais, estreptococos totais e espécies de Candida. Rugosidade de superfície e estabilidade dimensional de modelos de gesso também foram avaliados. Bochecho com solução bucal de clorexidina reduziu de forma significativamente (p<0,005) a contaminação microbiana. Pequenas mais significativas alterações dimensionais e de rugosidade de superfície foram produzidas quando hipoclorito de sódio foi utilizado como agente desinfetante pós-moldagem (p=0,005). Os resultados também demonstraram que o uso de solução de clorexidina 0,12% misturada ao pó de hidrocolóide irreversível reduziu a percentagem de microrganismos totais e estreptococos (p<0.001), sem causar alterações de rugosidade de superfície e estabilidade dimensional. Pode ser concluído que o uso de solução de clorexidina 0,12% usada como bochecho bucal ou misturada ao pó de hidrocolóide irreversível são métodos eficientes na redução microbiana de moldagens de alginato, sem causarem danos as propriedades físicas e mecânicas do material

Chlorine has effectively reduced the prevalence of waterborne diseases, however there are secondary consequences to this public health advancement. Disinfection byproducts (DBPs) are chemicals formed when chlorine reacts with natural organic matter (NOM) in water. A new class of DBPs, halobenzoquinones (HBQs), has recently been identified and data suggests it could be potentially carcinogenic and up to 1000 times more toxic than some regulated DBPs. So far, in vitro studies have assessed HBQ toxicity without taking into account its transformation in cell media into potentially less toxic compounds. This study evaluated the toxic effects of one HBQ, 2,6-DCBQ, and its transformed derivatives on colon epithelial and liver hepatoma cell lines by measuring intracellular reactive oxygen species production and cell viability post-DCBQ exposure. In addition, to better quantify the trade-off between exposure to waterborne pathogens and 2,6-DCBQ, the inactivation of a virus indicator (MS2), and formation of DCBQ were determined in chlorinated surface waters. Dose-dependent toxic effects were observed in both cell lines and transformed DCBQs were observed to be less toxic than their parent compound. MS2 inactivation occurred immediately post-chlorination, but DCBQ was detected simultaneously. Such findings indicate that this compound is toxic to human cells, including colon epithelial cells, which may be pertinent due to the possible association between chlorinated waters and colon cancer. Findings also suggest this DBP may be relevant in developing countries because HBQs may form in point-of-use chlorinated drinking waters. Furthermore, observed reduction in toxicity of media-transformed DCBQs calls current literature on HBQ toxicity into question.

This study evaluated the combination of ozone and granular activated carbon (GAC) treatment for the removal of sulfide and disinfection byproduct (DBP) precursors in drinking water at the pilot-scale. The research conducted was performed at the Auxiliary (Aux) and Main Water Treatment Plants (WTPs) in Sanford, Florida. Both WTPs rely upon groundwater sources that contain total sulfide ranging from 0.02 to 2.35 mg/L and total organic carbon (TOC) ranging from 0.61 to 2.20 mg/L. The Aux WTP’s raw water contains, on average, 88% more sulfide and 24% more TOC than the Main WTP. Haloacetic acids (HAA5) and total trihalomethanes (TTHMs) comprise the regulated forms of DBPs. HAA5 are consistently below the maximum contaminant level (MCL) of 60 μg/L, while TTHM ranges from 70 to 110 μg/L, at times exceeding the MCL of 80 μg/L in the distribution system. Ozone alone removed total sulfide and reduced UV-254 by about 60% at the Aux Plant and 35% at the Main Plant. Producing an ozone residual of 0.50 mg/L prevented the formation of bromate while removing approximately 35 to 60% concentration of DBP precursors as measured by UV-254. Operating the GAC unit at an empty bed contact time (EBCT) of 10 minutes for the Aux Plant and 5.5 minutes for the Main Plant resulted in 75% and 53% of UV-254 reduction, respectively. The average 120 hour TTHM formation potential for the Aux and Main Plants were 66 μg/L and 52 μg/L, respectively, after treatment by ozone and GAC. GAC exhaustion was deemed to have occurred after seven weeks for the Aux Plant and eleven weeks for the Main Plant. The GAC columns operated in three phases: an adsorption phase, a transitional phase, and a biologically activated carbon (BAC) phase. The GAC adsorption phase was found to produce the lowest TTHMs; however, TTHMs remained less than 80 μg/L during the BAC stage at each plant. BAC exhaustion did not occur iv during the course of this study. Ozone-GAC reduced chlorine demand by 73% for the Aux Plant and 10% for the Main Plant.

No description available.

Thesis (M.Tech.: Biotechnology)-Dept. of Biotechnology, Durban Institute Of Technology, 2005 xxiii, 172 p. : ill. ; 30 cm / The provision of safe and sanitary water is a constitutional right and above all, a necessity of life. As a result of the rapid urbanisation and the past policies of apartheid, a large population of South Africa dwell in informal settlements, where there is very little hope of development, as the government does not possess the resources that are necessary for a full-scale sanitation programme. Therefore, on-site treatments have been considered to provide sanitation in these dense peri-urban areas. The anaerobic baffled reactor (ABR) is one such sanitation system. This reactor utilises the phenomenon of anaerobic digestion to degrade substrates. One of the major disadvantages of any anaerobic treatment processes is the extreme sensitivity of the bacterial communities, thus inducing slow recovery rates following toxic shocks. Therefore, an understanding of these microbial consortia is essential to effectively control, operate and optimise the anaerobic reactor. Fluorescence in situ hybridization, 4’,6-diamidino-2-phenylindole (DAPI) staining and DNA sequencing techniques were applied to determine the microbial consortium, as well as their reactions to daily operating conditions. With an understanding of these populations and their responses to perturbations within the system, it is possible to construct an anaerobic system that is successful in its treatment of domestic wastewater. In situ hybridizations were conducted for three operating periods, each characterised by specific flow rates. Results showed Eubacterial population dominance over the Archaeal population throughout both of the operating periods investigated. However, these cells cumulatively consisted of 50% of the total biomass fraction, as determined by DAPI staining. Group-probes utilised revealed a high concentration of fermentative acidogenic bacteria, which lead to a decrease in the pH values. It was noted that the ABR did not separate the acidogenic and methanogenic phases, as expected. Therefore, the decrease in pH further inhibited the proliferation of Archaeal acetoclastic methanogens, which were not present in the second operating period. DNA sequencing results revealed the occurrence of the hydrogenotrophic Methanobacterium and Methanococcus genera and confirmed the presence of Methanosarcina. Sequencing of the bacterial DNA confirmed the presence of the low G+ C Gram Positives (Streptococcus), the high G+C Gram Positives (Propionibacterium) and the sulfate reducing bacteria (Desulfovibrio vulgaris). However, justifications were highly subjective due to a lack of supportive analytical data, such as acetate, volatile fatty acids and methane concentrations. Despite this, findings served to add valuable information, providing details on the specific microbial groups associated with ABR treatment processes.