Water Disinfection System Research Articles

Performance analysis of a solar photovoltaic hybrid system for electricity generation and simultaneous water disinfection of wild bacteria strains

A hybrid solar water disinfection and energy generation system for meeting the needs of safe drinking water and electricity was designed and tested in Alcalá de Henares (Spain) under summer climatic conditions to demonstrate the feasibility of the concept. Natural water sources with wild strains of Escherichia coli, total coliforms, Enterococcus spp. and Clostridium perfringens (including spores) were studied. Results showed that SOLWAT disinfection efficiency was higher than conventional PET bottles and that the water disinfection reactor located above the PV module did not affect the total energy output produced by the hybrid system in comparison to the single PV module, achieving the same power losses over the 6h of sun exposure in relation to their power at standard test conditions (STC).

Development of Drainage Water Disinfection System by Electric Shock in Recirculating Soilless Culture

Development of Drainage Water Disinfection System by Electric Shock in Recirculating Soilless Culture

Efficient Disinfection of Tap and Surface Water with Single High Power 285 nm LED and Square Quartz Tube

A small water disinfection system based on the combination of a strong single 25 mW LED with a wavelength of 285 nm and a short quartz tube with an outer rectangular cross section is presented. For the disinfection tests clear tap water and slightly turbid and yellow pond water are contaminated with high concentrations of Escherichia coli bacteria. These water samples are exposed to the germicidal 285 nm LED radiation while they flow through the quartz tube. The portion of surviving germs is determined by membrane filtration for different water qualities and flow rates. For clear tap water the bacteria concentration can be reduced by at least three orders of magnitude up to flow rates of about 20 L/h. In pond water the maximum flow rate for such a reduction is less than 3 L/h. These high disinfection capabilities and the small size of this system, allow its integration in medical systems for point of use disinfection or even its application in the Third World for decentralized water disinfection powered by small solar cells, because this disinfection capacity should be sufficient for small groups or families.

Water Purification and Disinfection by using Solar Energy: Towards Green Energy Challenge

The aim of this work was to design a solar water treatment plant for household purpose. Water purification is the process of eradicating detrimental chemicals, biological poisons, suspended solids and gases from contaminated water. In this work we have reported an investigation of compact filter which is cost effective for developing countries and ease of maintenance. We have arranged a solar water disinfection system that improves the microbiological quality of drinking water at household level. We get 14 L pure water and 16 ml water vapour within 240 min by using filtration method. From our work we get hot water up to 49°C. The efficiency of the system at sunny days and cloudy days are 18.23% and 18.13% respectively. This simple solar hybrid system helps to remove turbidity as well as chemical and pathogenic contaminants from water sources in the most affordable, and expedient manner possibly.

No increase in drug dispensing for acute gastroenteritis after Storm Klaus, France 2009.

During the night of 23-24 January 2009, Storm Klaus hit south-western France and caused power outages affecting 1,700,000 homes and stopping numerous pumping and drinking water disinfection systems. In France, medicalized acute gastroenteritis (MAGE) outbreaks are monitored by analysing the daily amount of reimbursements of medical prescriptions, registered in the French National Health Insurance database, at the 'commune' administrative level. As AGE is suspected to be associated with perturbations to water supply systems as well as power outages, Storm Klaus provided an opportunity to test its influence on the incidence of MAGE in the communes of three affected French departments (administrative areas larger than communes). The geographical exposure indicator was built by using the mapping of the water distribution zones, the reported distribution/production stoppages and their duration. Irrespective of exposure class, a relative risk of MAGE of 0.86 (95% confidence 0.84-0.88) was estimated compared with the 'unexposed' reference level. Although these results must be considered with caution because of a potential marked decrease in global medical consultation probably due to impassable roads, they do not suggest a major public health impact of Klaus in terms of increased MAGE incidence.

Listeriosis outbreaks in British Columbia, Canada, caused by soft ripened cheese contaminated from environmental sources.

Soft ripened cheese (SRC) caused over 130 foodborne illnesses in British Columbia (BC), Canada, during two separate listeriosis outbreaks. Multiple agencies investigated the events that lead to cheese contamination with Listeria monocytogenes (L.m.), an environmentally ubiquitous foodborne pathogen. In both outbreaks pasteurized milk and the pasteurization process were ruled out as sources of contamination. In outbreak A, environmental transmission of L.m. likely occurred from farm animals to personnel to culture solutions used during cheese production. In outbreak B, birds were identified as likely contaminating the dairy plant's water supply and cheese during the curd-washing step. Issues noted during outbreak A included the risks of operating a dairy plant in a farm environment, potential for transfer of L.m. from the farm environment to the plant via shared toilet facilities, failure to clean and sanitize culture spray bottles, and cross-contamination during cheese aging. L.m. contamination in outbreak B was traced to wild swallows defecating in the plant's open cistern water reservoir and a multibarrier failure in the water disinfection system. These outbreaks led to enhanced inspection and surveillance of cheese plants, test and release programs for all SRC manufactured in BC, improvements in plant design and prevention programs, and reduced listeriosis incidence.

Risk assessment and water safety plan: case study in Beijing, China.

Two typical rural water utilities in Beijing, China were chosen to describe the principles and applications of water safety plans (WSP), to provide a methodological guide for the actual application and improve the quality of rural drinking water quality, and to establish an appropriate method for WSP applied in rural water supply. Hazards and hazardous events were identified and risk assessment was conducted for rural water supply systems. A total of 13 and 12 operational limits were defined for two utilities, respectively. The main risk factors that affect the water safety were identified in water sources, water processes, water disinfection systems and water utility management. The main control measures were strengthening the water source protection, monitoring the water treatment processes, establishing emergency mechanisms, improving chemical input and operating system management. WSP can be feasibly applied to the management of a rural water supply.

ニプロ社製個人用RO装置NCR×eco Aoと個人用透析装置NCV-10を用いた全自動熱水消毒型個人用透析システムの構築および水質評価

ニプロ社製個人用RO装置NCR×eco Aoと個人用透析装置NCV-10を用いた全自動熱水消毒型個人用透析システムの構築および水質評価

Removal of bacteria, protozoa and viruses through a multiple-barrier household water disinfection system

Municipal water disinfection systems in some areas are not always able to meet water consumer needs, such as ensuring distributed water quality, because household water management can be a contributing factor in water re-contamination. This fact is related to the storage options that are common in places where water is scarce or is distributed over limited time periods. The aim of this study is to assess the removal capacity of a multiple-barrier water disinfection device for protozoa, bacteria, and viruses. Water samples were taken from households in Mexico City and spiked with a known amount of protozoa (Giardia cyst, Cryptosporidium oocyst), bacteria (Escherichia coli), and viruses (rotavirus, adenovirus, F-specific ribonucleic acid (FRNA) coliphage). Each inoculated sample was processed through a multiple-barrier device. The efficiency of the multiple-barrier device to remove E. coli was close to 100%, and more than 87% of Cryptosporidium oocysts and more than 98% of Giardia cysts were removed. Close to 100% of coliphages were removed, 99.6% of the adenovirus was removed, and the rotavirus was almost totally removed. An effect of site by zone was detected; this observation is important because the water characteristics could indicate the efficiency of the multiple-barrier disinfection device.

Application of UV light emitting diodes to batch and flow-through water disinfection systems

UV light emitting diodes (UV-LEDs) with peak emissions at 265, 280 and 310nm were applied to batch and flow-through water disinfection systems. Inactivation efficiency of Escherichia coli was compared between reactors and among emissions based on the exposure time and fluence. Combined emissions at 265/280, 265/310, 280/310 and 265/280/310nm were also tested in the flow-through reactor.The time-based inactivation efficiency was highest with the 280nm UV-LED while the fluence-based efficiency was highest with the 265nm UV-LED. In the batch reactor, the UV-LEDs at 265 and 280nm achieved over 4 log inactivation of E. coli at fluences of 10.8 and 13.8mJ/cm2, respectively, while the UV-LED at 310nm required 56.9mJ/cm2 for 0.6 log inactivation. The flow-through reactor showed tailing in the fluence-response curves and resulted in lower inactivation efficiency than the batch reactor, with lower fluence-based inactivation rate constant of 29% for 265nm and 32% for 280nm. Combined emissions were less efficient than the component emissions applied separately, and reduced output power for each UV-LED was observed for combined cases. This study provides key implications for the future application of UV-LEDs to water disinfection systems.

Assessment of a chlorine dioxide proprietary product for water and wastewater disinfection

Chlorine on its own is adequate for many, if not most, potable water pre-oxidation and disinfection systems at plants where the application is straightforward. Similarly, most wastewater plants can be disinfected by chlorine in one of its commercially available forms. However, when more intense pre-oxidation is required or significant iron or manganese is present in a potable supply, the use of alternative disinfectants is often preferable. Similarly, when secondary problems are present in wastewater effluent, such as high ammonia, a stronger oxidant may be preferable. Hitherto, the use of stronger oxidants has been limited to large works due to the complexity of the operational processes required. Recently, the use of ozone has spread to smaller works as new developments in equipment have become available. However, chlorine dioxide has not been used in small works until now. This paper provides details regarding a product which is simply dissolved in water in tablet or granular form and generates chlorine dioxide on solution in water. The solution is stable over weeks or even months and can be used for disinfection and or pre-oxidation purposes. The chemical was assessed in a series of tests. The performance of the chlorine dioxide product was compared against sodium hypochlorite, for different water types. The reduction in microbial counts was monitored in a secondary effluent sample and a high-ammonia secondary effluent sample. The oxidation ability in a high iron and manganese water was also assessed. A cost assessment was carried out and compared to the use of sodium hypochlorite. Other factors such as safety ease of use, and storage requirements are discussed. Keywords: chlorine, chlorine dioxide, oxidant, iron, manganese

Food and water security issues in Russia II: Water security in general population of Russian Arctic, Siberia and Far East, 2000–2011

BackgroundPoor state of water supply systems, shortage of water purification facilities and disinfection systems, low quality of drinking water generally in Russia and particularly in the regions of the Russian Arctic, Siberia and Far East have been defined in the literature. However, no standard protocol of water security assessment has been used in the majority of studies.Study design and methodsUniform water security indicators collected from Russian official statistical sources for the period 2000–2011 were used for comparison for 18 selected regions in the Russian Arctic, Siberia and Far East. The following indicators of water security were analyzed: water consumption, chemical and biological contamination of water reservoirs of Categories I and II of water sources (centralized – underground and surface, and non-centralized) and of drinking water.ResultsWater consumption in selected regions fluctuated from 125 to 340 L/person/day. Centralized water sources (both underground and surface sources) are highly contaminated by chemicals (up to 40–80%) and biological agents (up to 55% in some regions), mainly due to surface water sources. Underground water sources show relatively low levels of biological contamination, while chemical contamination is high due to additional water contamination during water treatment and transportation in pipelines. Non-centralized water sources are highly contaminated (both chemically and biologically) in 32–90% of samples analyzed. Very high levels of chemical contamination of drinking water (up to 51%) were detected in many regions, mainly in the north-western part of the Russian Arctic. Biological contamination of drinking water was generally much lower (2.5–12%) everywhere except Evenki AO (27%), and general and thermotolerant coliform bacteria predominated in drinking water samples from all regions (up to 17.5 and 12.5%, correspondingly). The presence of other agents was much lower: Coliphages – 0.2–2.7%, Clostridia spores, Giardia cysts, pathogenic bacteria, Rotavirus – up to 0.8%. Of a total of 56 chemical pollutants analyzed in water samples from centralized water supply systems, 32 pollutants were found to be in excess of hygienic limits, with the predominant pollutants being Fe (up to 55%), Cl (up to 57%), Al (up to 43%) and Mn (up to 45%).ConclusionIn 18 selected regions of the Russian Arctic, Siberia and Far East Category I and II water reservoirs, water sources (centralized – underground, surface; non-centralized) and drinking water are highly contaminated by chemical and biological agents. Full-scale reform of the Russian water industry and water security system is urgently needed, especially in selected regions.

A Rapid Low Power Ultra-Violet Light-Assisted Bacterial Sensor for Coliform Determination

Titanium dioxide (TiO2) particle-incorporated Prussian blue (PB) sensor for the detection and inactivation of Escherichia coli (E. coli) is developed in this study. The system requires low power ultra-violet (UV) light to photoactivate TiO2 particles and change of signal response is measured immediately upon irradiation using cyclic voltammetry. The generation of free radical species (OH.) and H2O2 from the oxidation of water by the hole (h+) are the main components which cause destruction of cell membrane and eventually result in the inactivation of cell. Our study also shows direct oxidation of cells by h+ as one of the mechanisms for cell inactivation due to the close contact between TiO2 particles and E. coli cells. Highly attractive features of this unique sensor include its ability to be regenerated and reused for at least three times without the use of harsh chemicals, good reproducibility and its specificity in bacteria sensing when tested against organic contaminants, which potentially reduce the operation cost when incorporated into water disinfection system. Its superior performance in detection of total coliform without additional steps of sample treatment is also demonstrated in river water. TiO2 particle-incorporated PB membrane sensor exhibits signal response with higher current output compared to PB-TiO2 coated screen printed carbon electrode (SPCE) due to its porous structure and higher surface area, suggesting its potential development into a powerful and low cost contamination monitoring tool.

A Self-Contained, PV-Powered Toilet and Domestic Waste Water Disinfection System

A Self-Contained, PV-Powered Toilet and Domestic Waste Water Disinfection SystemA comprehensive design review, development, construction, and performance testing of a sustainable, traditional infrastructure-free approach to the handling and processing of human sanitary waste including human fecal solids control, urine processing, and liquid wastewater treatment. The treatment scheme incorporates sludge disinfection, treatment, and volume reduction. This solar...Author(s)Yan QuAsghar AryanfarClement CidHao ZhangMichael R. HoffmannSourceProceedings of the Water Environment FederationDocument typeConference PaperPublisherWater Environment FederationPrint publication date Feb, 2013ISSN1938-6478DOI10.2175/193864713813503701Volume / Issue2013 / 2Content sourceDisinfection and Reuse SymposiumCopyright2013Word count317

Set membership identification of an excimer lamp for fast simulation

Excimer lamps are an efficient and sustainable source of ultra violet radiation, useful in water disinfection systems. In this paper black-box models of the electrical behavior and UV radiation process of an excimer lamp are estimated, employing Set Membership techniques. Approximations to the exact Set Membership model are derived, allowing reductions in the computational complexity of the system simulation. It is found that the obtained models allow faster simulations than the original Set Membership algorithm while maintaining good prediction capabilities, making them useful in power sources design.

Stove designed by US national lab improves lives in Darfur

In cutting the wood fuel requirement in half, the stove also reduces Darfuri women’s exposure to violence.

Economic comparison of conventional maintenance and electrochemical oxidation to warrant water safety in dental unit water lines.

Background: In preparation for implementation of a central water processing system at a dental department, we analyzed the costs of conventional decentralized disinfection of dental units against a central water treatment concept based on electrochemical disinfection.Methods: The cost evaluation included only the costs of annually required antimicrobial consumables and additional water usage of a decentralize conventional maintenance system for dental water lines build in the respective dental units and the central electrochemical water disinfection system, BLUE SAFETY™ Technologies.Results: In total, analysis of costs of 6 dental departments reviled additional annual costs for hygienic preventive measures of € 4,448.37. For the BLUE SAFETY™ Technology, the additional annual total agent consumption costs were € 2.18, accounting for approximately 0.05% of the annual total agent consumption costs of the conventional maintenance system. For both water processing concepts, the additional costs for energy could not be calculated, since the required data was not obtainable from the manufacturers.Discussion: For both concepts, the investment and maintenance costs were not calculated due to lack of manufacturer's data. Therefore, the results indicate the difference of costs for the required consumables only. Aside of the significantly lower annual costs for required consumables and disinfectants; a second advantage for the BLUE SAFETY™ Technology is its constant and automatic operation, which does not require additional staff resources. This not only safety human resources, but add additionally to cost saving.Conclusion: Since the antimicrobial disinfection capacity of the BLUE SAFETY™ was demonstrated previously and is well known, this technology, which is comparable or even superior in its non-corrosive effect, may be regarded as method of choice for continuous disinfection and prevention of biofilm formation in dental units’ water lines.

Dialysate Purification After Introduction of Automated Hot Water Disinfection System to Central Dialysis Fluid Delivery System

Most dialysis clinics in Japan have mainly adopted the central dialysis fluid delivery system (CDDS) to provide constant treatment to many patients. Chemical disinfection is the major maintenance method of the CDDS. Our clinic introduced an automated hot water disinfection system that used the heat conduction effect to disinfect a reverse osmosis (RO) device and dialysis fluid supply equipment. Endotoxin level and the amount of viable bacteria often showed abnormal values before introduction of this system. After its introduction, weekly disinfection resulted in endotoxin levels and the amount of viable bacteria lower than measurement sensitivity. In hot water disinfection, water heated to 90°C in the RO tank flows into the dialysis fluid supply equipment. The maximum temperature inside the tank of the supply equipment is 86.3°C. (We confirmed that the temperature was maintained at 80°C or more for 10 minutes or more during the monitoring.) Dialysate purification was maintained even after introduction of the automated hot water disinfection system and the dialysate could be supplied stably by the CDDS. Therefore, this disinfection system might be very useful in terms of both cost and safety, and can be used for dialysis treatment of multiple patients.

Thermal performance and biological evaluation of solar water disinfection systems using parabolic trough collectors

Thermal and optical performance of solar water disinfecting systems using parabolic trough collector, PTC, have been investigated experimentally and numerically. Four PTCs systems were designed, manufactured and field tested under the same weather conditions of Cairo 30°N. The four systems were installed to be compared thermally and biologically. Each system consists of a 2-m2 PTC and line-focus pipe to carry the water sample to be disinfected. In the first system (thermal system), a black painted stainless steel pipe covered by Pyrex glass envelope, to minimize the convective and radiative heat loss, is supported through the line-focus of the PTC. While in the second system (optical system) the contaminated water is used as absorber through a Pyrex glass tube, the two above processes are considered respectively in the third system. In the fourth system, a black tube including and surrounded by the contaminated water are considered as the absorber. The contaminated water is passed through the annular spac...

Hollow Fiber Membrane Decorated with Ag/MWNTs: Toward Effective Water Disinfection and Biofouling Control

The currently applied disinfection methods during water treatment provide effective solutions to kill pathogens, but also generate harmful byproducts, which are required to be treated with additional efforts. In this work, an alternative and safer water disinfection system consisting of silver nanoparticle/multiwalled carbon nanotubes (Ag/MWNTs) coated on a polyacrylonitrile (PAN) hollow fiber membrane, Ag/MWNTs/PAN, has been developed. Silver nanoparticles of controlled sizes were coated on polyethylene glycol-grafted MWNTs. Ag/MWNTs were then covalently coated on the external surface of a chemically modified PAN hollow fiber membrane to act as a disinfection barrier. A continuous filtration test using E. coli containing feedwater was conducted for the pristine PAN and Ag/MWNTs/PAN composite membranes. The Ag/MWNT coating significantly enhanced the antimicrobial activities and antifouling properties of the membrane against E. coli. Under the continuous filtration mode using E. coli feedwater, the relative flux drop over Ag/MWNTs/PAN was 6%, which was significantly lower than that over the pristine PAN (55%) at 20 h of filtration. The presence of the Ag/MWNT disinfection layer effectively inhibited the growth of bacteria in the filtration module and prevented the formation of biofilm on the surface of the membrane. Such distinctive antimicrobial properties of the composite membrane is attributed to the proper dispersion of silver nanoparticles on the external surface of the membrane, leading to direct contact with bacterium cells.