Science.gov

Sample records for air disinfection system

  1. UV Disinfection System for Cabin Air

    NASA Astrophysics Data System (ADS)

    Lim, Soojung

    Ultraviolet (UV) radiation is commonly used for disinfection of water. As a result of advancements made in the last 10-15 years, the analysis and design of UV disinfection systems for water is well developed. UV disinfection is also used for disinfection of air; however, despite the fact the UV-air systems have a longer record of application than UV-water systems, the methods used to analyze and design UV-air disinfection systems remain quite empirical. It is well-established that the effectiveness of UV-air systems is strongly affected by the type of microorganisms, the irradiation level/type (lamp power and wavelength), duration of irradiation (exposure time), air movement pattern (mixing degree), and relative humidity. This paper will describe ongoing efforts to evaluate, design and test a UV-air system based on first principles. Specific issues to be addressed in this work will include laboratory measurements of relevant kinetics (i.e., UV dose-response behavior) and numerical simulations designed to represent fluid mechanics and the radiation intensity field. UV dose-response behavior of test microorganism was measured using a laboratory (bench-scale) system. Target microorganisms (e.g., bacterial spores) were first applied to membrane filters at sub-monolayer coverage. The filters were then transferred to an environmental chamber at fixed relative humidity (RH) and allowed to equilibrate with their surroundings. Microorganisms were then subjected to UV exposure under a collimated beam. The experiment was repeated at RH values ranging from 20% to 100%. UV dose-response behavior was observed to vary with RH. For example, at 100% RH, a UV dose of 20 mJ/cm2 accomplished 90% (1 log10 units) of the B. subtilis spore inactivation, whereas 99 % (2 log10 units) inactivation was accomplished at this same UV dose under 20% RH conditions. However, at higher doses, the result was opposite of that in low dose. Reactor behavior is simulated using an integrated application

  2. UV disinfection system for cabin air

    NASA Astrophysics Data System (ADS)

    Lim, Soojung; Blatchley, Ernest R.

    2009-10-01

    The air of indoor cabin environments is susceptible to contamination by airborne microbial pathogens. A number of air treatment processes are available for inactivation or removal of airborne pathogens; included among these processes is ultraviolet (UV) irradiation. The effectiveness of UV-based processes is known to be determined by the combined effects of UV dose delivery by the reactor and the UV dose-response behavior of the target microbe(s). To date, most UV system designs for air treatment have been based on empirical approaches, often involving crude representations of dose delivery and dose-response behavior. The objective of this research was to illustrate the development of a UV system for disinfection of cabin air based on well-defined methods of reactor and reaction characterization. UV dose-response behavior of a test microorganism was measured using a laboratory (bench-scale) system. Target microorganisms (bacterial spores) were first applied to membrane filters at sub-monolayer coverage. The filters were then transferred to a humidity chamber at fixed relative humidity (RH) and allowed to equilibrate with their surroundings. Microorganisms were then subjected to UV exposure under a collimated beam. The experiment was repeated at RH values ranging from 20% to 100%. UV dose-response behavior was observed to vary with RH. For example, at 100% RH, a UV dose of 20 mJ/cm 2 accomplished 99.7% (2.5 log10 U) of the Bacillus subtilis spore inactivation, whereas 99.94% (3.2 log10 U) inactivation was accomplished at this same UV dose under 20% RH conditions. To determine reactor behavior, UV dose-response behavior was combined with simulated results of computational fluid dynamics (CFD) and radiation intensity field models. This modeling approach allowed estimating the UV dose distribution delivered by the reactor. The advantage of this approach is that simulation of many reactor configurations can be done in a relatively short period of time. Moreover, by

  3. Disinfecting Filters For Recirculated Air

    NASA Technical Reports Server (NTRS)

    Pilichi, Carmine A.

    1992-01-01

    Simple treatment disinfects air filters by killing bacteria, algae, fungi, mycobacteria, viruses, spores, and any other micro-organisms filters might harbor. Concept applied to reusable stainless-steel wire mesh filters and disposable air filters. Treatment used on filters in air-circulation systems in spacecraft, airplanes, other vehicles, and buildings to help prevent spread of colds, sore throats, and more-serious illnesses.

  4. [Disinfectants and main sanitary and preventive measures for protection of ventilation and air-conditioning systems from Legionella contamination].

    PubMed

    Gerasimov, V N; Golov, E A; Khramov, M V; Diatlov, I A

    2008-01-01

    The study was devoted to selection and assessment of disinfecting preparations for prevention of contamination by Legionella. Using system of criteria for quality assessment of disinfectants, seven newdomestic ones belonging to quaternary ammonium compounds class or to oxygen-containing preparations and designed for disinfecting of air-conditioning and ventilation systems were selected. Antibacterial and disinfecting activities of working solutions of disinfectants were tested in laboratory on the test-surfaces and test-objects of premises' air-conditioning and ventilation systems contaminated with Legionella. High antimicrobial and disinfecting activity of new preparations "Dezactiv-M", "ExtraDez", "Emital-Garant", "Aquasept Plus", "Samarovka", "Freesept", and "Ecobreeze Oxy" during their exposure on objects and materials contaminated with Legionella was shown. Main sanitary and preventive measures for defending of air-conditioning and ventilation systems from contamination by Legionella species were presented.

  5. Use of a portable air disinfecting system to remove seeded coliphage in hospital rooms.

    PubMed

    Verhougstraete, Marc; Reynolds, Kelly

    2016-06-01

    Health care-associated infections are a major problem worldwide, and the airborne route is believed to be a contributory source of secondary health care-associated infections. This study examined the efficacy of a portable air disinfecting system to remove seeded coliphage virus from the air in hospitals rooms. Aerosolized coliphage concentrations were not statistically different between treatment and no treatment measurements. However, future research should focus on additional investigations in the patient rooms that incorporate fomite and air testing alongside portable air filtration devices.

  6. Evaluation of a teflon based ultraviolet light system on the disinfection of water in a textile air washer

    SciTech Connect

    Smith, J.E.; Whisnant, R.B.

    1987-08-01

    The report provides an in-depth evaluation of an ultraviolet (UV) disinfection unit as applied to the treatment of cooling water in a textile air washer system. The UV unit tests used a teflon tube to transport the aquatic phase. The unit reduced microbial populations and maintained an average level of 10,000 Colony formed unites/mL for the 6-month testing period, without the addition of biocides. No cleaning or other maintenance was required of the wetted surfaces during the testing period. Slime deposits observed on walls of the air washer during chemical treatment were also eliminated. The UV unit can be utilized on both cooling towers and air washers without extensive installation.

  7. Photocatalytic disinfection of indoor air

    SciTech Connect

    Goswami, D.Y.; Trivedi, D.M.; Block, S.S.

    1997-02-01

    The present study demonstrated the antibacterial effect of photocatalytic oxidation in indoor air using titanium dioxide as the catalyst. Through a series of experiments, it was determined that titanium dioxide did enhance the inactivation rate of the microorganisms under certain conditions. In these experiments the air velocity, relative humidity, and UV (350 nm) intensity were varied. It was found that higher velocities retarded the destruction rate due to the low retention time in the reactor. TiO{sub 2} also did not accelerate the reaction at low humidities (30%). At a relative humidity of 50%, there was complete inactivation of the organisms, but at higher humidities (85%), 10% of the organisms were still viable. The experiments showed that at higher UV intensities, most of the activation was done by the UV photons. However, the photons were not able to completely inactivate the microorganisms. In the photocatalysis experiments there was complete inactivation of the bacteria.

  8. Impact of surface disinfection and sterile draping of furniture on room air quality in a cardiac procedure room with a ventilation and air-conditioning system (extrusion airflow, cleanroom class 1b (DIN 1946-4)).

    PubMed

    Below, Harald; Ryll, Sylvia; Empen, Klaus; Dornquast, Tina; Felix, Stefan; Rosenau, Heike; Kramer, Sebastian; Kramer, Axel

    2010-09-21

    In a cardiac procedure room, ventilated by a ventilation and air-conditioning system with turbulent mixed airflow, a protection zone in the operating area could be defined through visualization of airflows. Within this protection zone, no turbulence was detectable in the room air.Under the given conditions, disinfection of all surfaces including all furniture and equipment after the last operation and subsequent draping of furniture and all equipment that could not be removed from the room with sterile surgical drapes improved the indoor room air quality from cleanroom class C to cleanroom class B. This also allows procedures with elevated requirements to be performed in room class 1b.

  9. Silver disinfection in water distribution systems

    NASA Astrophysics Data System (ADS)

    Silvestry Rodriguez, Nadia

    Silver was evaluated as disinfectant to maintain water quality in water distribution system. It was used to inhibit growth of two opportunistic bacteria in planktonik form and in biofilm formation in Robbins devices with stainless steel and PVC surfaces. The results of this work show that silver is a potential secondary disinfectant to be used in water distribution systems.

  10. Can pulsed xenon ultraviolet light systems disinfect aerobic bacteria in the absence of manual disinfection?

    PubMed

    Jinadatha, Chetan; Villamaria, Frank C; Ganachari-Mallappa, Nagaraja; Brown, Donna S; Liao, I-Chia; Stock, Eileen M; Copeland, Laurel A; Zeber, John E

    2015-04-01

    Whereas pulsed xenon-based ultraviolet light no-touch disinfection systems are being increasingly used for room disinfection after patient discharge with manual cleaning, their effectiveness in the absence of manual disinfection has not been previously evaluated. Our study indicates that pulsed xenon-based ultraviolet light systems effectively reduce aerobic bacteria in the absence of manual disinfection. These data are important for hospitals planning to adopt this technology as adjunct to routine manual disinfection.

  11. Disinfection of water distribution systems for Legionella.

    PubMed

    Lin, Y S; Stout, J E; Yu, V L; Vidic, R D

    1998-06-01

    Hospital-acquired legionnaires' disease arises from the presence of Legionella in hospital water systems. Legionella not only persists in hot water tanks but is also found in the biofilm throughout the entire water distribution system. Conditions within water systems that promote Legionella colonization include water temperature, configuration and age of the hot water tank, physicochemical constituents of the water, plumbing materials, and commensal microflora. Hospital-acquired legionnaires' disease has been prevented by instituting control measures directed at the water distribution system. These include superheat-and-flush, copper/silver ionization, ultraviolet light, instantaneous heating systems, and hyperchlorination. Each of the above disinfection methods has been proven to be effective in the short-term, but long-term efficacy has been difficult due to limitations associated with each method. The complexities of Legionella disinfection, including advantages and disadvantages of each method, are reviewed. A successful Legionella prevention program requires cooperation and communication among hospital administrative personnel, engineers, and infection control staff. Routine environmental surveillance cultures for Legionella are the critical component for successful long-term disinfection. Culture results document the efficacy of the disinfection method and alert the hospital staff to consider Legionella in hospitalized patients with pneumonia. PMID:9643393

  12. OPTIMAL SCHEDULING OF BOOSTER DISINFECTION IN WATER DISTRIBUTION SYSTEMS

    EPA Science Inventory

    Booster disinfection is the addition of disinfectant at locations distributed throughout a water distribution system. Such a strategy can reduce the mass of disinfectant required to maintain a detectable residual at points of consumption in the distribution system, which may lea...

  13. [Disinfection by-products reduction of combined disinfection by chlorine and monochloramines in distribution system].

    PubMed

    Liu, Jing; Chen, Chao; Zhang, Xiao-Jian

    2009-09-15

    Halogen disinfection by-products of four chlorined disinfection processes with long contact time in distribution system was compared in the work. These four disinfection processes are free chlorine, monochloramines, free chlorine disinfection in clearwelles while chloramines in distribution system, sequential chlorination disinfection with short-term free chlorine plus chloramines. According to the research, free chlorine generates most trihalomethanes (THMs) and haloacetic acids (HAAs) both in clearwells and distribution system, while monochloramines barely yield halogen DBPs. Free chlorine disinfection in clearwelles while chloramines in distribution system could reduce 9.6% of THMs and 42% of HAAs in 24 h contact time of distribution system compared with free chlorine. But free chlorine has contacted with water for 2 h in this process, halogen DBPs have been yielded substantially. Process of sequential chlorination disinfection could control DBPs more effectively due to keeping a short contact time of free chlorine and water. 48% of THMs and 72% of HAAs are reduced in 24h compared with free chlorine. In conclusion, sequential chlorination disinfection is a more effective disinfection process for controlling DBPs and water safety.

  14. Air plasma effect on dental disinfection

    SciTech Connect

    Duarte, S.; Murata, R. M.; Saxena, D.; Kuo, S. P.; Chen, C. Y.; Huang, K. J.; Popovic, S.

    2011-07-15

    A nonthermal low temperature air plasma jet is characterized and applied to study the plasma effects on oral pathogens and biofilms. Experiments were performed on samples of six defined microorganisms' cultures, including those of gram-positive bacteria and fungi, and on a cultivating biofilm sample of Streptococcus mutans UA159. The results show that the plasma jet creates a zone of microbial growth inhibition in each treated sample; the zone increases with the plasma treatment time and expands beyond the entire region directly exposed to the plasma jet. With 30s plasma treatment twice daily during 5 days of biofilm cultivation, its formation was inhibited. The viability of S. mutans cells in the treated biofilms dropped to below the measurable level and the killed bacterial cells concentrated to local regions as manifested by the fluorescence microscopy via the environmental scanning electron microscope. The emission spectroscopy of the jet indicates that its plasma effluent carries an abundance of reactive atomic oxygen, providing catalyst for the observed plasma effect.

  15. Air plasma effect on dental disinfection

    NASA Astrophysics Data System (ADS)

    Duarte, S.; Kuo, S. P.; Murata, R. M.; Chen, C. Y.; Saxena, D.; Huang, K. J.; Popovic, S.

    2011-07-01

    A nonthermal low temperature air plasma jet is characterized and applied to study the plasma effects on oral pathogens and biofilms. Experiments were performed on samples of six defined microorganisms' cultures, including those of gram-positive bacteria and fungi, and on a cultivating biofilm sample of Streptococcus mutans UA159. The results show that the plasma jet creates a zone of microbial growth inhibition in each treated sample; the zone increases with the plasma treatment time and expands beyond the entire region directly exposed to the plasma jet. With 30s plasma treatment twice daily during 5 days of biofilm cultivation, its formation was inhibited. The viability of S. mutans cells in the treated biofilms dropped to below the measurable level and the killed bacterial cells concentrated to local regions as manifested by the fluorescence microscopy via the environmental scanning electron microscope. The emission spectroscopy of the jet indicates that its plasma effluent carries an abundance of reactive atomic oxygen, providing catalyst for the observed plasma effect.

  16. Quantification of air plasma chemistry for surface disinfection

    NASA Astrophysics Data System (ADS)

    Pavlovich, Matthew J.; Clark, Douglas S.; Graves, David B.

    2014-12-01

    Atmospheric-pressure air plasmas, created by a variety of discharges, are promising sources of reactive species for the emerging field of plasma biotechnology because of their convenience and ability to operate at ambient conditions. One biological application of ambient-air plasma is microbial disinfection, and the ability of air plasmas to decontaminate both solid surfaces and liquid volumes has been thoroughly established in the literature. However, the mechanism of disinfection and which reactive species most strongly correlate with antimicrobial effects are still not well understood. We describe quantitative gas-phase measurements of plasma chemistry via infrared spectroscopy in confined volumes, focusing on air plasma generated via surface micro-discharge (SMD). Previously, it has been shown that gaseous chemistry is highly sensitive to operating conditions, and the measurements we describe here extend those findings. We quantify the gaseous concentrations of ozone (O3) and nitrogen oxides (NO and NO2, or NOx) throughout the established ‘regimes’ for SMD air plasma chemistry: the low-power, ozone-dominated mode; the high-power, nitrogen oxides-dominated mode; and the intermediate, unstable transition region. The results presented here are in good agreement with previously published experimental studies of aqueous chemistry and parameterized models of gaseous chemistry. The principal finding of the present study is the correlation of bacterial inactivation on dry surfaces with gaseous chemistry across these time and power regimes. Bacterial decontamination is most effective in ‘NOx mode’ and less effective in ‘ozone mode’, with the weakest antibacterial effects in the transition region. Our results underscore the dynamic nature of air plasma chemistry and the importance of careful chemical characterization of plasma devices intended for biological applications.

  17. Regenerable Iodine Water-Disinfection System

    NASA Technical Reports Server (NTRS)

    Sauer, Richard L.; Colombo, Gerald V.; Jolly, Clifford D.

    1994-01-01

    Iodinated resin bed for disinfecting water regenerated to extend useful life. Water flows through regeneration bed of crystalline iodine during regeneration. At other times, flow diverted around regeneration bed. Although regeneration cycle manually controlled readily automated to start and stop according to signals from concentration sensors. Further benefit of regeneration is bed provides highly concentrated biocide source when needed. Concentrated biocide used to superiodinate system after contamination from routine maintenance or unexpected introduction of large concentration of microbes.

  18. Disinfection.

    ERIC Educational Resources Information Center

    Gould, J. P.; Haas, C. N.

    1978-01-01

    Presents a literature review of wastewater disinfection for 1978. This review covers areas such as: (1) mechanisms of inactivation of negative microorganisms by chlorine and ozone; and (2) the effects of various treatment on over-all water quality. A list of 61 references is also presented. (HM)

  19. DISINFECTION

    EPA Science Inventory

    The primary goal of the disinfection process in drinking water treatment is the inactivation of microbial pathogens. These pathogens comprise a diverse group of organisms which serve as the etiological agents of waterborne disease. Included in this group are bacterial, viral and ...

  20. Regenerable Iodine Water-Disinfection System

    NASA Technical Reports Server (NTRS)

    Sauer, Richard L.; Colombo, Gerald V.; Jolly, Clifford D.

    1994-01-01

    Iodinated resin bed for disinfecting water regenerated to extend its useful life. Water flows through regeneration bed of crystalline iodine during regeneration. At other times, flow diverted around regeneration bed. Although regeneration cycle was manually controlled in demonstration, readily automated to start and stop according to signals and stop according to signals from concentration sensors. Further benefit of regeneration is that regeneration bed provides highly concentrated biocide source (200 mg/L) when needed. Concentrated biocide used to superiodinate system after contamination from routine maintenance or unexpected introduction of large concentration of microbes.

  1. Ultraviolet (UV) Disinfection for Drinking Water Systems

    EPA Science Inventory

    UV disinfection is an effective process for inactivating many microbial pathogens in water with potential to serve as stand-alone treatment or in combination with other disinfectants. USEPA provided guidance on the validation of UV reactors nearly a decade ago. Since then, lesson...

  2. Disinfection of indoor air microorganisms in stack room of university library using gaseous chlorine dioxide.

    PubMed

    Hsu, Ching-Shan; Lu, Ming-Chun; Huang, Da-Ji

    2015-02-01

    As with all indoor public spaces in Taiwan, the stack rooms in public libraries should meet the air quality guidelines laid down by the Taiwan Environmental Protection Administration. Accordingly, utilizing a university library in Taiwan for experimental purposes, this study investigates the efficiency of gaseous chlorine dioxide (ClO2) as a disinfection agent when applied using three different treatment modes, namely a single-daily disinfection mode (SIM), a twice-daily disinfection mode (TWM), and a triple-daily disinfection mode (TRM). For each treatment mode, the ClO2 is applied using an ultrasonic aerosol device and is performed both under natural lighting conditions and under artificial lighting conditions. The indoor air quality is evaluated before and after each treatment session by measuring the bioaerosol levels of bacteria and fungi. The results show that for all three disinfection modes, the application of ClO2 reduces the indoor bacteria and fungi concentrations to levels lower than those specified by the Taiwan EPA (i.e., bacteria <1500 CFU/m(3), fungi <1000 CFU/m(3)), irrespective of the lighting conditions under which the disinfection process is performed. For each disinfection mode, a better disinfection efficiency is obtained under natural lighting conditions since ClO2 readily decomposes under strong luminance levels. Among the three treatment modes, the disinfection efficiencies of the TWM and TRM modes are very similar under natural lighting conditions and are significantly better than that of the SIM mode. Thus, overall, the results suggest that the TWM treatment protocol represents the most cost-effective and efficient method for meeting the indoor air quality requirements of the Taiwan EPA. PMID:25626564

  3. Amoebicidal activity of a preserved contact lens multipurpose disinfecting solution compared to a disinfection/neutralisation peroxide system.

    PubMed

    Buck, S L; Rosenthal, R A; Abshire, R L

    1998-01-01

    The amoebicidal activity of a contact lens multipurpose disinfecting solution (MPDS) containing polyquaternium-1 and myristamidopropyl dimethylamine was compared to a disinfection/neutralisation peroxide system against Acanthamoeba castellanii and Acanthamoeba polyphaga trophozoites and cysts. A quantitative microtitre method was used to evaluate the solutions. The MPDS showed similar amoebicidal activity to the disinfection/neutralisation peroxide system against the trophozoites of both species and equal or more rapid activity against the cysts of both species. PMID:16303382

  4. Corrosion control and disinfection studies in spacecraft water systems. [considering Saturn 5 orbital workshop

    NASA Technical Reports Server (NTRS)

    Shea, T. G.

    1974-01-01

    Disinfection and corrosion control in the water systems of the Saturn 5 Orbital Workshop Program are considered. Within this framework, the problem areas of concern are classified into four general areas: disinfection; corrosion; membrane-associated problems of disinfectant uptake and diffusion; and taste and odor problems arising from membrane-disinfectant interaction.

  5. Stability and effectiveness of chlorine disinfectants in water distribution systems

    SciTech Connect

    Olivieri, V.P.; Snead, M.C.; Kruse, C.W.; Kawata, K.

    1986-11-01

    A test system for water distribution was used to evaluate the stability and effectiveness of three residual disinfectants - free chlorine, combined chlorine, and chlorine dioxide - when challenged with a sewage contaminant. The test distribution system consisted of the street main and internal plumbing for two barracks at Fort George G. Meade, MD. To the existing pipe network, 152 m (500 ft) of 13-mm (0.5 in.) copper pipe were added for sampling, and 60 m (200 ft) of 2.54-cm (1.0 in.) plastic pipe were added for circulation. The levels of residual disinfectants tested were 0.2 mg/L and 1.0 mg/L as available chlorine. In the absence of a disinfectant residual, microorganisms in the sewage contaminant were consistently recovered at high levels. The presence of any disinfectant residual reduced the microorganism level and frequency of occurrence at the consumer's tap. Free chlorine was the most effective residual disinfectant and may serve as a marker or flag in the distribution network. Free chlorine and chlorine dioxide were the least stable in the pipe network. The loss of disinfectant in the pipe network followed first-order kinetics. The half-life determined in static tests for free chlorine, chlorine dioxide, and combined chlorine was 140, 93, and 1680 min.

  6. Use of Hydrogen Peroxide to Disinfect Hydroponic Plant Growth Systems

    NASA Technical Reports Server (NTRS)

    Barta, Daniel J.; Henderson, Keith

    2000-01-01

    Hydrogen peroxide was studied as an alternative to conventional bleach and rinsing methods to disinfect hydroponic plant growth systems. A concentration of 0.5% hydrogen peroxide was found to be effective. Residual hydrogen peroxide can be removed from the system by repeated rinsing or by flowing the solution through a platinum on aluminum catalyst. Microbial populations were reduced to near zero immediately after treatment but returned to pre-disinfection levels 2 days after treatment. Treating nutrient solution with hydrogen peroxide and planting directly into trays being watered with the nutrient solution without replenishment, was found to be detrimental to lettuce germination and growth.

  7. Humidifier disinfectants, unfinished stories.

    PubMed

    Choi, Yeyong; Paek, Domyung

    2016-01-01

    Once released into the air, humidifier disinfectants became tiny nano-size particles, and resulted in chemical bronchoalveolitis. Families had lost their most beloved members, and even some of them became broken. Based on an estimate of two million potential victims who had experienced adverse effects from the use of humidifier disinfectants, we can say that what we have observed was only the tip of the iceberg. Problems of entire airways, as well as other systemic effects, should be examined, as we know these nano-size particles can irritate cell membranes and migrate into systemic circulation. The story of humidifier disinfectant is not finished yet. PMID:26987713

  8. [Electrochemical disinfection using the gas diffusion electrode system].

    PubMed

    Xu, Wen-Ying; Li, Ping; Dong, Bin

    2010-01-01

    Study on the electrochemical disinfection with the H2O2 produced at the gas diffusion electrode (GDE) prepared from active carbon/ poly-tetrafluoroethylene (PTFE) was performed in the non-membrane cell. The effects of PTFE mass fraction W(PTFE) and content of the pore-forming agent in GDE m(NH4CO3), operating conditions such as pH value and oxygen flow rate Q(o2)) on disinfection were investigated, respectively. The experimental results showed that H2 O2 reached peak production at W(PTFE) of 0.5 in GDE. Addition of the pore-forming agent in the appropriate amount improved the disinfection, and this phenomenon was more obvious at neutral pH than at acidic pH. BET specific area analysis indicated that the average pore size in the membrane electrode first decreased significantly with the increasing amount of pore-forming agent, and then increased moderately. This helped the mass transfer of oxygen at the GDE. Adsorption made little or no progress to kill the bacteria during the electrolysis. Drop of pH value resulted in a rapid rise of the germicidal efficacy. This system had a broad pH coverage: when total bacterial count in raw water was 10(6) CFU x mL(-1), pH 3-10,the germicidal efficacy was greater than 80% after 30 min electrolysis using the GDE with W(Pt) of 3 per thousand as cathode. Increase of the oxygen flow rate Q(o2) within limits had little influence on the production of H2 O2 and the succeeding disinfection. On one hand, resistance of the solution and energy consumption on the disinfection increased at high oxygen flow rate, which gave rise to an increase in the operating cost of disinfection with the GDE system; on the other hand, treatment time could be reduced reasonably at high oxygen flow rate, which leads to reduction of equipment investment. Killing mechanism study showed that the direct oxidation and formation of the free radicals at the anode played a greater role in the beginning, and then the oxidative indirect effect of the generated H2 O2 at

  9. Zero-G Condensing Heat Exchanger with Integral Disinfection

    NASA Technical Reports Server (NTRS)

    Burke, Kenneth A. (Inventor)

    2012-01-01

    The system that operates in a zero gravity environment and has an integral ozone generating capability is disclosed. The system contributes to the control of metabolic water vapors in the air, and also provided disinfection of any resulting condensate within the system, as well as disinfection of the air stream that flows throughout the disclosed system.

  10. Institutional Tuberculosis Transmission. Controlled Trial of Upper Room Ultraviolet Air Disinfection: A Basis for New Dosing Guidelines

    PubMed Central

    Mphaphlele, Matsie; Dharmadhikari, Ashwin S.; Jensen, Paul A.; Rudnick, Stephen N.; van Reenen, Tobias H.; Pagano, Marcello A.; Leuschner, Wilhelm; Sears, Tim A.; Milonova, Sonya P.; van der Walt, Martie; Stoltz, Anton C.; Weyer, Karin

    2015-01-01

    Rationale: Transmission is driving the global tuberculosis epidemic, especially in congregate settings. Worldwide, natural ventilation is the most common means of air disinfection, but it is inherently unreliable and of limited use in cold climates. Upper room germicidal ultraviolet (UV) air disinfection with air mixing has been shown to be highly effective, but improved evidence-based dosing guidelines are needed. Objectives: To test the efficacy of upper room germicidal air disinfection with air mixing to reduce tuberculosis transmission under real hospital conditions, and to define the application parameters responsible as a basis for proposed new dosing guidelines. Methods: Over an exposure period of 7 months, 90 guinea pigs breathed only untreated exhaust ward air, and another 90 guinea pigs breathed only air from the same six-bed tuberculosis ward on alternate days when upper room germicidal air disinfection was turned on throughout the ward. Measurements and Main Results: The tuberculin skin test conversion rates (>6 mm) of the two chambers were compared. The hazard ratio for guinea pigs in the control chamber converting their skin test to positive was 4.9 (95% confidence interval, 2.8–8.6), with an efficacy of approximately 80%. Conclusions: Upper room germicidal UV air disinfection with air mixing was highly effective in reducing tuberculosis transmission under hospital conditions. These data support using either a total fixture output (rather than electrical or UV lamp wattage) of 15–20 mW/m3 total room volume, or an average whole-room UV irradiance (fluence rate) of 5–7 μW/cm2, calculated by a lighting computer-assisted design program modified for UV use. PMID:25928547

  11. Thermal disinfection of hotels, hospitals, and athletic venues hot water distribution systems contaminated by Legionella species.

    PubMed

    Mouchtouri, Varvara; Velonakis, Emmanuel; Hadjichristodoulou, Christos

    2007-11-01

    Legionella spp. (> or = 500 cfu liter(-1)) were detected in 92 of 497 water distribution systems (WDS) examined. Thermal disinfection was applied at 33 WDS. After the first and second application of the disinfection procedure, 15 (45.4%) and 3 (9%) positive for remedial actions WDS were found, respectively. Legionella pneumophila was more resistant to thermal disinfection than Legionella non-pneumophila spp. (relative risk [RR]=5.4, 95% confidence intervals [CI]=1-35). WDS of hotels with oil heater were more easily disinfected than those with electrical or solar heater (RR=0.4 95% CI=0.2-0.8). Thermal disinfection seems not to be efficient enough to eliminate legionellae, unless repeatedly applied and in combination with extended heat flushing, and faucets chlorine disinfection.

  12. Thermal disinfection of hotels, hospitals, and athletic venues hot water distribution systems contaminated by Legionella species.

    PubMed

    Mouchtouri, Varvara; Velonakis, Emmanuel; Hadjichristodoulou, Christos

    2007-11-01

    Legionella spp. (> or = 500 cfu liter(-1)) were detected in 92 of 497 water distribution systems (WDS) examined. Thermal disinfection was applied at 33 WDS. After the first and second application of the disinfection procedure, 15 (45.4%) and 3 (9%) positive for remedial actions WDS were found, respectively. Legionella pneumophila was more resistant to thermal disinfection than Legionella non-pneumophila spp. (relative risk [RR]=5.4, 95% confidence intervals [CI]=1-35). WDS of hotels with oil heater were more easily disinfected than those with electrical or solar heater (RR=0.4 95% CI=0.2-0.8). Thermal disinfection seems not to be efficient enough to eliminate legionellae, unless repeatedly applied and in combination with extended heat flushing, and faucets chlorine disinfection. PMID:17980243

  13. 40 CFR 141.544 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.544 Section 141.544 Protection of Environment... Benchmark § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone or chlorine dioxide for primary disinfection your system...

  14. 40 CFR 141.544 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.544 Section 141.544 Protection of Environment... Benchmark § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone or chlorine dioxide for primary disinfection your system...

  15. 40 CFR 141.544 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.544 Section 141.544 Protection of Environment... Benchmark § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone or chlorine dioxide for primary disinfection your system...

  16. 40 CFR 141.544 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.544 Section 141.544 Protection of Environment... Benchmark § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone or chlorine dioxide for primary disinfection your system...

  17. 40 CFR 141.544 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.544 Section 141.544 Protection of Environment... Benchmark § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone or chlorine dioxide for primary disinfection your system...

  18. 40 CFR 141.533 - What data must my system collect to calculate a disinfection profile?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false What data must my system collect to calculate a disinfection profile? 141.533 Section 141.533 Protection of Environment ENVIRONMENTAL PROTECTION... at each residual disinfectant concentration sampling point during peak hourly flow; (b) If...

  19. 40 CFR 141.533 - What data must my system collect to calculate a disinfection profile?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false What data must my system collect to calculate a disinfection profile? 141.533 Section 141.533 Protection of Environment ENVIRONMENTAL PROTECTION... at each residual disinfectant concentration sampling point during peak hourly flow; (b) If...

  20. 40 CFR 141.533 - What data must my system collect to calculate a disinfection profile?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false What data must my system collect to calculate a disinfection profile? 141.533 Section 141.533 Protection of Environment ENVIRONMENTAL PROTECTION... at each residual disinfectant concentration sampling point during peak hourly flow; (b) If...

  1. 40 CFR 141.533 - What data must my system collect to calculate a disinfection profile?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false What data must my system collect to calculate a disinfection profile? 141.533 Section 141.533 Protection of Environment ENVIRONMENTAL PROTECTION... at each residual disinfectant concentration sampling point during peak hourly flow; (b) If...

  2. 40 CFR 141.533 - What data must my system collect to calculate a disinfection profile?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false What data must my system collect to calculate a disinfection profile? 141.533 Section 141.533 Protection of Environment ENVIRONMENTAL PROTECTION... at each residual disinfectant concentration sampling point during peak hourly flow; (b) If...

  3. 40 CFR 141.532 - How does my system develop a disinfection profile and when must it begin?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Profile § 141.532 How...

  4. 40 CFR 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.535 Section 141.535 Protection of Environment... § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone, or chlorine dioxide for primary disinfection, you must...

  5. 40 CFR 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.535 Section 141.535 Protection of Environment... § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone, or chlorine dioxide for primary disinfection, you must...

  6. 40 CFR 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.535 Section 141.535 Protection of Environment... § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone, or chlorine dioxide for primary disinfection, you must...

  7. 40 CFR 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.535 Section 141.535 Protection of Environment... § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone, or chlorine dioxide for primary disinfection, you must...

  8. 40 CFR 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.535 Section 141.535 Protection of Environment... § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone, or chlorine dioxide for primary disinfection, you must...

  9. 40 CFR 141.532 - How does my system develop a disinfection profile and when must it begin?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false How does my system develop a disinfection profile and when must it begin? 141.532 Section 141.532 Protection of Environment ENVIRONMENTAL... my system develop a disinfection profile and when must it begin? A disinfection profile consists...

  10. A comparative study of the microbiologic effectiveness of chemical disinfectants and peroxide-neutralizer systems.

    PubMed

    Rosenthal, R A; Stein, J M; McAnally, C L; Schlech, B A

    1995-04-01

    We evaluated the antimicrobial activity of chemical and hydrogen peroxide-neutralizer contact lens disinfection systems. The acute activity, storage, and recontamination potential of the two disinfection methods were compared by challenging the disinfectants with Staphylococcus spp., Pseudomonas aeruginosa, Serratia marcescens, Candida spp., and Aspergillus fumigatus. Chemical disinfectants preserved with polyquaternium-1 and polyhexamethylene biguanide and hydrogen peroxide-neutralizer systems with no additional preservatives were tested. Additionally, lens cases from patients using both systems were evaluated. Lens cases from patients using peroxide-neutralizer systems tended toward heavier contamination (31.8%) than the cases disinfected with a chemical system (20.3%, P = 0.16). The laboratory results showed that the differences in activity of chemical and peroxide-neutralizer systems was not statistically significant at the disinfection times against Staphylococcus epidermidis, S. marcescens, Candida parapsilosis, and A. fumigatus (P = 0.1037 to P = 0.5412). A statistical difference was shown against C. albicans (P = 0.0176) in favor of the peroxide-neutralizer systems. The reverse was true during storage. Although the chemical disinfectants maintained the population of microorganisms, the bacteria and yeast increased to over 10(7) CFU/mL in neutralized peroxide systems. Overall, the results emphasize the importance of contact lens products containing preservatives for lasting protection from microorganisms.

  11. Disinfection of water in recirculating aquaculture systems with peracetic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peracetic acid (PAA) has become a favoured alternative to chlorination in the disinfection of municipal waste water in recent years. It is also commonly used in the food industry as a disinfectant. Based on PAA concentration, the disulfide linkage in enzymes and proteins of microorganisms can be bro...

  12. Experience of using heat citric acid disinfection method in central dialysis fluid delivery system.

    PubMed

    Sakuma, Koji; Uchiumi, Nobuko; Sato, Sumihiko; Aida, Nobuhiko; Ishimatsu, Taketo; Igoshi, Tadaaki; Kodama, Yoshihiro; Hotta, Hiroyuki

    2010-09-01

    We applied the heat citric acid disinfection method in the main part of the central dialysis fluid delivery system (MPCDDS), which consists of a multiple-patient dialysis fluid supply unit, dialysis console units, and dialysis fluid piping. This disinfection method has been used for single-patient dialysis machines, but this is the first trial in the MPCDDS. We examined, by points of safety and disinfection effect, whether this disinfection method is comparable to conventional disinfection methods in Japan. The conventional disinfection method is a combination of two disinfectants, sodium hypochlorite and acetic acid, used separately for protein removal and decalcification. Consequently, total microbial counts and endotoxin concentrations fully satisfied the microbiological requirements for standard dialysis fluid of ISO 11663. From our results and discussion, this heat citric acid disinfection method is proved to be safe and reliable for MPCDDS. However, to satisfy the microbiological requirements for ultrapure dialysis fluid, further consideration for this method in MPCDDS including the reverse osmosis device composition and piping is necessary.

  13. Effects of phosphorus on biofilm disinfections in model drinking water distribution systems.

    PubMed

    Fang, Wei; Hu, Jiangyong; Ong, Say Leong

    2010-09-01

    Drinking water biofilm development is affected by the available nutrient levels and the presence of disinfectants. Phosphorus is recognized as another important limiting nutrient besides organic carbon. In this study, drinking water biofilms were developed in annular reactors to examine the effects of phosphorus on the biofilm disinfections with free chlorine and monochloramine. Phosphorus addition was found to increase the biofilm cell number but decrease the exopolysaccharides (EPS) production. The disinfection efficacies of both free chlorine and monochloramine were increased when phosphorus was added into the reactor systems. At the same disinfection dosages, monochloramine showed greater biofilm removal efficiency than free chlorine. Monochloramine could be a better choice than free chlorine in biofilm disinfection when phosphate-based corrosion inhibitors are applied.

  14. 40 CFR 141.542 - What must my system do if we are considering a significant change to disinfection practices?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Benchmark § 141.542 What must my system do if we are considering a significant change to disinfection... calculate a disinfection benchmark(s) as described in §§ 141.543 and 141.544 and provide the benchmark(s) to... Giardia lamblia (and, if necessary, viruses) and disinfection benchmark; (c) An analysis of how...

  15. 40 CFR 141.542 - What must my system do if we are considering a significant change to disinfection practices?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving Fewer Than 10,000 People Disinfection... consultation and approval process: (a) A description of the proposed change; (b) The disinfection profile...

  16. 40 CFR 141.542 - What must my system do if we are considering a significant change to disinfection practices?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Benchmark § 141.542 What must my system do if we are considering a significant change to disinfection... calculate a disinfection benchmark(s) as described in §§ 141.543 and 141.544 and provide the benchmark(s) to... Giardia lamblia (and, if necessary, viruses) and disinfection benchmark; (c) An analysis of how...

  17. 40 CFR 141.542 - What must my system do if we are considering a significant change to disinfection practices?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Benchmark § 141.542 What must my system do if we are considering a significant change to disinfection... calculate a disinfection benchmark(s) as described in §§ 141.543 and 141.544 and provide the benchmark(s) to... Giardia lamblia (and, if necessary, viruses) and disinfection benchmark; (c) An analysis of how...

  18. 40 CFR 141.542 - What must my system do if we are considering a significant change to disinfection practices?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Benchmark § 141.542 What must my system do if we are considering a significant change to disinfection... calculate a disinfection benchmark(s) as described in §§ 141.543 and 141.544 and provide the benchmark(s) to... Giardia lamblia (and, if necessary, viruses) and disinfection benchmark; (c) An analysis of how...

  19. Disinfectant Penetration into Nitrifying Drinking Water Distribution System Biofilm Using Microelectrodes

    EPA Science Inventory

    Nitrification within drinking water distribution systems reduces water quality, causes difficulties maintaining adequate disinfectant residual, and poses public health concerns including exposure to nitrite, nitrate, and opportunistic pathogenic microorganisms. Monochloramine is...

  20. Installation of a water disinfection system in a Mexico City hospital.

    PubMed

    Juárez Mendoza, J; Martínez Rosales, G; Díaz Sánchez, J; Brust Mascher, E; Brust Carmona, H

    1992-01-01

    With a view to evaluating a small-scale water disinfection system based on production and application of oxidizing gases, the level of equivalent residual chlorine and the degree of contamination by fecal and total coliform bacteria was assessed at various points in the drinking water system of a Mexico City hospital before and after installation of the disinfection equipment. Tests done in May and June 1989, prior to installation of the equipment, showed that residual chlorine concentrations were lower than the national standard in most of the samples and that a sizable portion of these samples were also contaminated with fecal and total coliform concentrations exceeding national standards. After installation of the disinfection system at the main inflow to the hospital's drinking water supply in August 1989, the equivalent residual chlorine concentrations were found adequate and no coliform bacteria were detected. These results indicate that the oxidant mixture generated by the newly installed system was effectively disinfecting the water.

  1. Electrochemical disinfection using the gas diffusion electrode system.

    PubMed

    Xu, Wenying; Li, Ping; Dong, Bin

    2010-01-01

    A study on the electrochemical disinfection with H2O2 generated at the gas diffusion electrode (GDE) from active carbon/polytetrafluoroethylene was performed in a non-membrane cell. The effects of Pt load and the pore-forming agent content in GDE, and operating conditions were investigated. The experimental results showed that nearly all bacterial cultures inoculated in the secondary effluent from wastewater treatment plant could be inactivated within 30 min at a current density of 10 mA/cm2. The disinfection improved with increasing Pt load. Addition of the pore-forming agent NH4HCO3 improved the disinfection, while a drop in the pH value resulted in a rapid rise of germicidal efficacy and the disinfection time was shortened with increasing oxygen flow rate. Adsorption was proved to be ineffective in destroying bacteria, while germicidal efficacy increased with current density. The acceleration rate was different, it initially increased with current density. Then decreased, and finally reached a maximum at a current density of 6.7 mA/cm2. The disinfection also improved with decreasing total bacterial count. The germicidal efficacy in the cathode compartment was approximately the same as in the anode compartment, indicating that the contribution of direct oxidation and the indirect treatment of bacterial cultures by hydroxyl radical was similar to the oxidative indirect effect of the generated H2O2.

  2. Entrapped cell system for decentralized hospital wastewater treatment: inhibitory effect of disinfectants.

    PubMed

    Siripattanakul-Ratpukdi, Sumana

    2012-01-01

    This study aims to improve decentralized hospital wastewater treatment inhibited by disinfectants by using calcium alginate cell entrapment technique. The effects of disinfectant types (glutaraldehyde, povidone iodine (PI) and a potassium hydroxide solution) and disinfectant concentrations, cell entrapment conditions (cell-to-matrix ratios) and cell loadings were investigated. The batch experiments were conducted using synthetic wastewater with initial chemical oxygen demand (COD) of approximately 370 mg/L and acclimated activated sludge. Among three disinfectants, PI substantially affected the wastewater treatment efficiency (inhibition of 40%) while other disinfectants exhibited inhibition effects of less than 9%. The results also indicated that the entrapped cells obviously performed better than the free cells. The cell-to-matrix ratio of 1:20 (v/v) provided the highest treatment efficiency of 86% (inhibition of 9%) while the free cell system had inhibition of 47%. The system at the entrapped cell loading of 2000 mg/L performed the highest COD removal of 62% for ten-cycle sequencing batch operation. A scanning electron microscope image provided information on entrapped cell structure subjected to the disinfectant. PMID:23393973

  3. High efficiency air cycle air conditioning system

    SciTech Connect

    Rannenberg, G. C.

    1985-11-19

    An air cycle air conditioning system is provided with regenerative heat exchangers upstream and downstream of an expansion turbine. A closedloop liquid circulatory system serially connects the two regenerative heat exchangers for regeneration without the bulk associated with air-to-air heat exchange. The liquid circulatory system may also provide heat transport to a remote sink heat exchanger and from a remote load as well as heat exchange within the sink heat exchanger and load for enhanced compactness and efficiency.

  4. Vulnerability of water distribution systems to pathogen intrusion: how effective is a disinfectant residual?

    PubMed

    Propato, Marco; Uber, James G

    2004-07-01

    Can the spread of infectious disease through water distribution systems be halted by a disinfectant residual? This question is overdue for an answer. Regulatory agencies and water utilities have long been concerned about accidental intrusions of pathogens into distribution system pipelines (i.e., cross-connections) and are increasingly concerned about deliberate pathogen contamination. Here, a simulation framework is developed and used to assess the vulnerability of a water system to microbiological contamination. The risk of delivering contaminated water to consumers is quantified by a network water quality model that includes disinfectant decay and disinfection kinetics. The framework is applied to two example networks under a worst-case deliberate intrusion scenario. Results show that the risk of consumer exposure is affected by the residual maintenance strategy employed. The common regulation that demands a "detectable" disinfectant residual may not provide effective consumer protection against microbial contamination. A chloramine residual, instead of free chlorine, may significantly weaken this final barrier against pathogen intrusions. Moreover, the addition of a booster station at storage tanks may improve consumer protection without requiring excessive disinfectant.

  5. Culture systems: air quality.

    PubMed

    Thomas, Theodore

    2012-01-01

    Poor laboratory air quality is a known hazard to the culture of human gametes and embryos. Embryologists and chemists have employed analytical methods for identifying and measuring bulk and select air pollutants to assess the risk they pose to the embryo culture system. However, contaminant concentrations that result in gamete or embryotoxicity are poorly defined. Combating the ill effects of poor air quality requires an understanding of how toxicants can infiltrate the laboratory, the incubator, and ultimately the culture media. A further understanding of site-specific air quality can then lead to the consideration of laboratory design and management strategies that can minimize the deleterious effects that air contamination may have on early embryonic development in vitro.

  6. [Use od ozone for disinfection of ships' system of water supply contaminated by Pseudomonas aeruginosa].

    PubMed

    Rakhmanin, Iu A; Strikalenko, T V; Mokienko, A V; Stoianova, N V; Gutsel', Iu I

    1990-11-01

    Experimental substantiation is given of the use of ozone in doses, recommended for disinfection of water and ship water supply systems infected by Pseudomonas aeruginosa. The positive effect of ozonation of water supply systems infected by Pseudomonas aeruginosa was confirmed by results of field testing on ships of the Black sea marine steam-navigation.

  7. Air heating system

    DOEpatents

    Primeau, John J.

    1983-03-01

    A self-starting, fuel-fired, air heating system including a vapor generator, a turbine, and a condenser connected in a closed circuit such that the vapor output from the vapor generator is conducted to the turbine and then to the condenser where it is condensed for return to the vapor generator. The turbine drives an air blower which passes air over the condenser for cooling the condenser. Also, a condensate pump is driven by the turbine. The disclosure is particularly concerned with the provision of heat exchanger and circuitry for cooling the condensed fluid output from the pump prior to its return to the vapor generator.

  8. Verification of the efficiency of chemical disinfection and sanitation measures in in-building distribution systems.

    PubMed

    Lenz, J; Linke, S; Gemein, S; Exner, M; Gebel, J

    2010-06-01

    Previous investigations of biofilms, generated in a silicone tube model have shown that the number of colony forming units (CFU) can reach 10(7)/cm(2), the total cell count (TCC) of microorganisms can be up to 10(8)cells/cm(2). The present study focuses on the situation in in-building distribution systems. Different chemical disinfectants were tested for their efficacy on drinking water biofilms in silicone tubes: free chlorine (electrochemically activated), chlorine dioxide, hydrogen peroxide (H(2)O(2)), silver, and fruit acids. With regard to the widely differing manufacturers' instructions for the usage of their disinfectants three different variations of the silicone tube model were developed to simulate practical use conditions. First the continuous treatment, second the intermittent treatment, third the efficacy of external disinfection treatment and the monitoring for possible biofilm formation with the Hygiene-Monitor. The working experience showed that it is important to know how to handle the individual disinfectants. Every active ingredient has its own optimal application concerning its concentration, exposure time, physical parameters like pH, temperature or redox potential. When used correctly all products tested were able to reduce the CFU to a value below the detection limit. Most of the active ingredients could not significantly reduce the TCC/cm(2), which means that viable microorganisms may still be present in the system. Thus the question arises what happened with these cells? In some cases SEM pictures of the biofilm matrix after a successful disinfection still showed biofilm residues. According to these results, no general correlation between CFU/cm(2), TCC/cm(2) and the visualised biofilm matrix on the silicone tube surface (SEM) could be demonstrated after a treatment with disinfectants.

  9. ENVIRONMENTAL TECHNOLOGY VERIFICATION: JOINT (NSF-EPA) VERIFICATION STATEMENT AND REPORT: UV DISINFECTION FOR REUSE APPLICATIONS, ONDEO DEGREMONT, INC., AQUARAY® 40 HO VLS DISINFECTION SYSTEM

    EPA Science Inventory

    Verification testing of the Ondeo Degremont, Inc. Aquaray® 40 HO VLS Disinfection System to develop the UV delivered dose flow relationship was conducted at the Parsippany-Troy Hills wastewater treatment plant test site in Parsippany, New Jersey. Three reactor modules were m...

  10. Disinfection Processes.

    PubMed

    Munakata, Naoko; Kuo, Jeff

    2016-10-01

    A review of the literature published in 2015 on topics relating to disinfection processes is presented. This review is divided into the following sections: disinfection methods, disinfection byproducts, and microbiology and microbial communities. PMID:27620087

  11. Efficacy of various chemical disinfectants on biofilms formed in spacecraft potable water system components.

    PubMed

    Wong, Wing C; Dudinsky, Lynn A; Garcia, Veronica M; Ott, Charlie M; Castro, Victoria A

    2010-07-01

    As the provision of potable water is critical for successful habitation of the International Space Station (ISS), life support systems were installed in December 2008 to recycle both humidity from the atmosphere and urine to conserve available water in the Station. In-flight pre-consumption testing from the dispensing needle at the Potable Water Dispenser (PWD) indicated that bacterial concentrations exceeded the current ISS specifications of 50 colony-forming units (CFU) ml(-1). Subsequent investigations revealed that a corrugated stainless steel flex hose upstream of the dispensing needle in the PWD was filled with nonsterile water and left at room temperature for more than 1 month before launch. To simulate biofilm formation that was suspected in the flight system, sterile flex hoses were seeded with a consortium of bacterial isolates previously recovered from other ISS water systems, including Ralstonia pickettii, Burkholderia multivorans, Caulobacter vibrioides, and Cupriavidus pauculus. After incubation for 5 days, the hoses were challenged with various chemical disinfectants including hydrogen peroxide (H2O2), colloidal silver, and buffered pH solutions to determine the ability of the disinfectants to decrease and maintain bacterial concentrations below ISS specifications. The disinfection efficacy over time was measured by collecting daily heterotrophic plate counts after exposure to the disinfectants. A single flush with either 6% H2O2 solution or a mixture of 3% H2O2 and 400 ppb colloidal silver effectively reduced the bacterial concentrations to <1 CFU ml(-1) for a period of up to 3 months.

  12. Efficacy of Various Chemical Disinfectants on Biofilms Formed in Spacecraft Potable Water System Component

    NASA Technical Reports Server (NTRS)

    Wong, Willy; Garcia, Veronica; Castro, Victoria; Ott, Mark; Duane

    2009-01-01

    As the provision of potable water is critical for successful habitation of the International Space Station (ISS), life support systems were installed in December 2008 to recycle both humidity from the atmosphere and urine to conserve available water in the vehicle. Pre-consumption testing from the dispensing needle at the Potable Water Dispenser (PWD) indicated that bacterial concentrations exceeded the current ISS specifications of 50 colony forming units (CFU) per ml. Subsequent investigations revealed that a corrugated stainless steel flex hose upstream of the dispensing needle in the PWD was filled with non-sterile water and left at room temperature for over one month before launch. To simulate biofilm formation that was suspected in the flight system, sterile flex hoses were seeded with a consortium of bacterial isolates previously recovered from other ISS water systems, which included Ralstonia pickettii, Burkholderia multivorans, Caulobacter vibrioides., and Cupriavidus pauculus. After 5 days of incubation, these hoses were challenged with various chemical disinfectants including hydrogen peroxide, colloidal silver, and buffered pH solutions to determine the ability of the disinfectants to decrease and maintain bacterial concentrations below ISS specifications. Disinfection efficacy over time was measured by collecting daily heterotrophic plate counts following exposure to the disinfectants. A single flush with either 6% hydrogen peroxide solution or a mixture of 3% hydrogen peroxide and 400 ppb colloidal silver effectively reduced the bacterial concentrations to less than 1 CFU/ml for a period of up to 2 months. Testing results indicated that hydrogen peroxide and mixtures of hydrogen peroxide and colloidal silver have tremendous potential as alternative disinfectants for ISS water systems.

  13. [Bone bank management using a thermal disinfection system (Lobator SD-1). A critical analysis].

    PubMed

    Hofmann, C; von Garrel, T; Gotzen, L

    1996-07-01

    In the study presented on 380 allogenic bone donations from living and organ donors, we analyzed the safety of allograft handling bone-band documentation, logistics and costs. For transplant treatment we routinely used a thermal disinfection system (Lobator SD-1). From 380 allograft donors, 400 bone transplants were gained. The rejection rate was 12.2%. After thermal disinfection for 1 h at 80 degrees C, the grafts were cryopreserved at -80 degrees C and released from the bone bank for potential transplantation after 14-16 days. Five of 730 microbiological specimens showed bacterial contamination after thermal graft decontamination. The bacterial species found on the allografts normally have an inactivation temperature under 80 degrees C. Therefore, only secondary contamination can explain the positive bacteriological test results. With reform of the health care system the economical aspects of bone banking have triggered more interest. The cost for one bone transplant released from the bone bank was 424.75 DM: the overall cost for the bone bank in one year was 75,076 DM. Laboratory (58.2%) and material costs (22.5%) were the major factors. Personnel costs and apparatus costs were relatively low (< 20%). With introduction of the thermal disinfection system (Lobator SD-1) into the bone bank, the safety of allogenic bone transplants was greatly improved. Clinical and serological donor screening must be performed according to international bone bank directives. Considering the low rejection rate and the short turnover rate, the economical costs could be reduced. Using an appropriate disinfection system (thermal disinfection at 80 degrees C), laboratory tests covering venereal diseases, malaria and cytomegalia are no longer required. Also, secondary HIV testing of living donors can be omitted without reducing the safety of the transplant.

  14. Formation of nitrogenous disinfection by-products in 10 chlorinated and chloraminated drinking water supply systems.

    PubMed

    Liew, Deborah; Linge, Kathryn L; Joll, Cynthia A

    2016-09-01

    The presence of nitrogenous disinfection by-products (N-DBPs) in drinking water supplies is a public health concern, particularly since some N-DBPs have been reported to be more toxic than the regulated trihalomethanes and haloacetic acids. In this paper, a comprehensive evaluation of the presence of N-DBPs in 10 drinking water supply systems in Western Australia is presented. A suite of 28 N-DBPs, including N-nitrosamines, haloacetonitriles (HANs), haloacetamides (HAAms) and halonitromethanes (HNMs), were measured and evaluated for relationships with bulk parameters in the waters before disinfection. A number of N-DBPs were frequently detected in disinfected waters, although at generally low concentrations (<10 ng/L for N-nitrosamines and <10 μg/L for other N-DBPs) and below health guideline values where they exist. While there were no clear relationships between N-DBP formation and organic nitrogen in the pre-disinfection water, N-DBP concentrations were significantly correlated with dissolved organic carbon (DOC) and ammonia, and these, in addition to high bromide in one of the waters, led to elevated concentrations of brominated HANs (26.6 μg/L of dibromoacetonitrile). There were significant differences in the occurrence of all classes of N-DBPs between chlorinated and chloraminated waters, except for HNMs, which were detected at relatively low concentrations in both water types. Trends observed in one large distribution system suggest that N-DBPs can continue to form or degrade within distribution systems, and redosing of disinfectant may cause further by-product formation.

  15. Formation of nitrogenous disinfection by-products in 10 chlorinated and chloraminated drinking water supply systems.

    PubMed

    Liew, Deborah; Linge, Kathryn L; Joll, Cynthia A

    2016-09-01

    The presence of nitrogenous disinfection by-products (N-DBPs) in drinking water supplies is a public health concern, particularly since some N-DBPs have been reported to be more toxic than the regulated trihalomethanes and haloacetic acids. In this paper, a comprehensive evaluation of the presence of N-DBPs in 10 drinking water supply systems in Western Australia is presented. A suite of 28 N-DBPs, including N-nitrosamines, haloacetonitriles (HANs), haloacetamides (HAAms) and halonitromethanes (HNMs), were measured and evaluated for relationships with bulk parameters in the waters before disinfection. A number of N-DBPs were frequently detected in disinfected waters, although at generally low concentrations (<10 ng/L for N-nitrosamines and <10 μg/L for other N-DBPs) and below health guideline values where they exist. While there were no clear relationships between N-DBP formation and organic nitrogen in the pre-disinfection water, N-DBP concentrations were significantly correlated with dissolved organic carbon (DOC) and ammonia, and these, in addition to high bromide in one of the waters, led to elevated concentrations of brominated HANs (26.6 μg/L of dibromoacetonitrile). There were significant differences in the occurrence of all classes of N-DBPs between chlorinated and chloraminated waters, except for HNMs, which were detected at relatively low concentrations in both water types. Trends observed in one large distribution system suggest that N-DBPs can continue to form or degrade within distribution systems, and redosing of disinfectant may cause further by-product formation. PMID:27523603

  16. Air System Information Management

    NASA Technical Reports Server (NTRS)

    Filman, Robert E.

    2004-01-01

    I flew to Washington last week, a trip rich in distributed information management. Buying tickets, at the gate, in flight, landing and at the baggage claim, myriad messages about my reservation, the weather, our flight plans, gates, bags and so forth flew among a variety of travel agency, airline and Federal Aviation Administration (FAA) computers and personnel. By and large, each kind of information ran on a particular application, often specialized to own data formats and communications network. I went to Washington to attend an FAA meeting on System-Wide Information Management (SWIM) for the National Airspace System (NAS) (http://www.nasarchitecture.faa.gov/Tutorials/NAS101.cfm). NAS (and its information infrastructure, SWIM) is an attempt to bring greater regularity, efficiency and uniformity to the collection of stovepipe applications now used to manage air traffic. Current systems hold information about flight plans, flight trajectories, weather, air turbulence, current and forecast weather, radar summaries, hazardous condition warnings, airport and airspace capacity constraints, temporary flight restrictions, and so forth. Information moving among these stovepipe systems is usually mediated by people (for example, air traffic controllers) or single-purpose applications. People, whose intelligence is critical for difficult tasks and unusual circumstances, are not as efficient as computers for tasks that can be automated. Better information sharing can lead to higher system capacity, more efficient utilization and safer operations. Better information sharing through greater automation is possible though not necessarily easy.

  17. Formation of disinfection byproducts in a recirculating mariculture system: emerging concerns.

    PubMed

    Qiang, Zhimin; Zhang, Haiting; Dong, Huiyu; Adams, Craig; Luan, Gang; Wang, Lei

    2015-02-01

    Disinfection is commonly employed in recirculating mariculture systems (RMS) to control animal diseases and improve seawater quality; however, little is known about the occurrence of disinfection byproducts (DBPs) formed in such RMS. Beijing Aquarium is a typical RMS with artificially prepared seawater and mainly adopts a decentralized treatment strategy for different animal tanks, including sand filtration, foam fractionation, and disinfection (O3, UV, and O3/ClO2). This study reveals that the adopted disinfection processes were highly effective in controlling marine heterotrophic bacteria; however, some concerns were raised on the formation of various kinds of DBPs, including secondary oxidants, inorganic oxyanions, and hazardous organic species. Free chlorine and free bromine were generated from ozonation at health-relevant concentrations. High concentrations of BrO3(-) and ClO3(-) were formed in mammal tanks, which exceeded the USEPA-regulated maximum contaminant level (MCL) for drinking water by 19-25 and 52-54 times, respectively. Extremely high concentrations of NO3(-) were detected in mammal tanks, which considerably exceeded the MCL regulated by the Sea Water Quality Standard of China for the mariculture industry (Class II) by about 1100 times. Undoubtedly, the presence of various DBPs poses serious health threats to aquarium animals. To solve these problems, potential control measures for DBPs are proposed.

  18. Impact of chlorinated disinfection on copper corrosion in hot water systems

    NASA Astrophysics Data System (ADS)

    Montes, J. Castillo; Hamdani, F.; Creus, J.; Touzain, S.; Correc, O.

    2014-09-01

    In France, hot water quality control inside buildings is occasionally ensured by disinfection treatments using temperature increases or addition of sodium hypochlorite (between 0.5 ppm and 1 ppm residual free chlorine). This disinfectant is a strong oxidiser and it could interact with metallic pipes usually used in hot water systems. This work deals with the study of the impact of these treatments on the durability of copper pipes. The objective of this work was to investigate the influence of sodium hypochlorite concentration and temperature on the copper corrosion mechanism. Copper samples were tested under dynamic and static conditions of ageing with sodium hypochlorite solutions ranging from 0 to 100 ppm with temperature at 50 °C and 70 °C. The efficiency of a corrosion inhibitor was investigated in dynamic conditions. Visual observations and analytical analyses of the internal surface of samples was studied at different ageing duration. Corrosion products were characterised by X-ray diffraction and Raman spectroscopy. Temperature and disinfectant were found to considerably affect the copper corrosion mechanism. Surprisingly, the corrosiveness of the solution was higher at lower temperatures. The temperature influences the nature of corrosion products. The protection efficiency is then strongly depend on the nature of the corrosion products formed at the surface of copper samples exposed to the aggressive solutions containing different concentration of disinfectant.

  19. Chlorine Disinfection of Atypical Mycobacteria Isolated from a Water Distribution System

    PubMed Central

    Le Dantec, Corinne; Duguet, Jean-Pierre; Montiel, Antoine; Dumoutier, Nadine; Dubrou, Sylvie; Vincent, Véronique

    2002-01-01

    We studied the resistance of various mycobacteria isolated from a water distribution system to chlorine. Chlorine disinfection efficiency is expressed as the coefficient of lethality (liters per minute per milligram) as follows: Mycobacterium fortuitum (0.02) > M. chelonae (0.03) > M. gordonae (0.09) > M. aurum (0.19). For a C · t value (product of the disinfectant concentration and contact time) of 60 mg · min · liter−1, frequently used in water treatment lines, chlorine disinfection inactivates over 4 log units of M. gordonae and 1.5 log units of M. fortuitum or M. chelonae. C · t values determined under similar conditions show that even the most susceptible species, M. aurum and M. gordonae, are 100 and 330 times more resistant to chlorine than Escherichia coli. We also investigated the effects of different parameters (medium, pH, and temperature) on chlorine disinfection in a chlorine-resistant M. gordonae model. Our experimental results follow the Arrhenius equation, allowing the inactivation rate to be predicted at different temperatures. Our results show that M. gordonae is more resistant to chlorine in low-nutrient media, such as those encountered in water, and that an increase in temperature (from 4°C to 25°C) and a decrease in pH result in better inactivation. PMID:11872446

  20. Efficacy of different disinfectant systems on alginate and addition silicone impression materials of Indian and international origin: a comparative evaluation.

    PubMed

    Samra, R K; Bhide, S V

    2010-09-01

    Study was planned to evaluate the efficacy of commonly used disinfectants and to study qualitatively and quantitatively the persistence of microflora on the untreated (control group) and the disinfected impression surface after 24 h. Disinfectant systems used were immersion systems like glutaraldehyde, sodium hypochlorite and the ultraviolet chamber. The effect of disinfectant on most commonly used Indian impression materials was carried out in this study and results compared with the most commonly used foreign brands for irreversible hydrocolloid and addition silicone. Impressions were made of 25 healthy volunteers. These were disinfected and incubated in an incubator for 24 h at 37°C for aerobic organisms. The inoculation in nutrient media was done to test the viability of microorganisms that can persist after rinsing and disinfection of the impression surface. The colony forming units were counted and compared with that of control group. Control group of all the impression material samples showed growth of Streptococcus viridans, Diphtheroids, Streptococcus pneumoniae to a greater extent. The growth of Candida albicans, Pseudomonas aerugenosa and Staphyloccus albus was present in all the groups but to a lesser extent. The persistence of the microflora on the impression surface of both the studied brands was similar but the concentration of organisms in the alginate control group was two folds as compared to addition silicone group. Use of ultraviolet chamber gave better results compared to the studied immersion systems. All the disinfection systems were effective in reducing the microbial load with ultraviolet chamber as the most effective.

  1. Aerosol Disinfection Capacity of Slightly Acidic Hypochlorous Acid Water Towards Newcastle Disease Virus in the Air: An In Vivo Experiment.

    PubMed

    Hakim, Hakimullah; Thammakarn, Chanathip; Suguro, Atsushi; Ishida, Yuki; Nakajima, Katsuhiro; Kitazawa, Minori; Takehara, Kazuaki

    2015-12-01

    Existence of bioaerosol contaminants in farms and outbreaks of some infectious organisms with the ability of transmission by air increase the need for enhancement of biosecurity, especially for the application of aerosol disinfectants. Here we selected slightly acidic hypochlorous acid water (SAHW) as a candidate and evaluated its virucidal efficacy toward a virus in the air. Three-day-old conventional chicks were challenged with 25 doses of Newcastle disease live vaccine (B1 strain) by spray with nebulizer (particle size <3 μm in diameter), while at the same time reverse osmosis water as the control and SAHW containing 50 or 100 parts per million (ppm) free available chlorine in pH 6 were sprayed on the treated chicks with other nebulizers. Exposed chicks were kept in separated cages in an isolator and observed for clinical signs. Oropharyngeal swab samples were collected from 2 to 5 days postexposure from each chick, and then the samples were titrated with primary chicken kidney cells to detect the virus. Cytopathic effects were observed, and a hemagglutination test was performed to confirm the result at 5 days postinoculation. Clinical signs (sneezing) were recorded, and the virus was isolated from the control and 50 ppm treatment groups, while no clinical signs were observed in and no virus was isolated from the 100 ppm treatment group. The virulent Newcastle disease virus (NDV) strain Sato, too, was immediately inactivated by SAHW containing 50 ppm chlorine in the aqueous phase. These data suggest that SAHW containing 100 ppm chlorine can be used for aerosol disinfection of NDV in farms. PMID:26629621

  2. Aerosol Disinfection Capacity of Slightly Acidic Hypochlorous Acid Water Towards Newcastle Disease Virus in the Air: An In Vivo Experiment.

    PubMed

    Hakim, Hakimullah; Thammakarn, Chanathip; Suguro, Atsushi; Ishida, Yuki; Nakajima, Katsuhiro; Kitazawa, Minori; Takehara, Kazuaki

    2015-12-01

    Existence of bioaerosol contaminants in farms and outbreaks of some infectious organisms with the ability of transmission by air increase the need for enhancement of biosecurity, especially for the application of aerosol disinfectants. Here we selected slightly acidic hypochlorous acid water (SAHW) as a candidate and evaluated its virucidal efficacy toward a virus in the air. Three-day-old conventional chicks were challenged with 25 doses of Newcastle disease live vaccine (B1 strain) by spray with nebulizer (particle size <3 μm in diameter), while at the same time reverse osmosis water as the control and SAHW containing 50 or 100 parts per million (ppm) free available chlorine in pH 6 were sprayed on the treated chicks with other nebulizers. Exposed chicks were kept in separated cages in an isolator and observed for clinical signs. Oropharyngeal swab samples were collected from 2 to 5 days postexposure from each chick, and then the samples were titrated with primary chicken kidney cells to detect the virus. Cytopathic effects were observed, and a hemagglutination test was performed to confirm the result at 5 days postinoculation. Clinical signs (sneezing) were recorded, and the virus was isolated from the control and 50 ppm treatment groups, while no clinical signs were observed in and no virus was isolated from the 100 ppm treatment group. The virulent Newcastle disease virus (NDV) strain Sato, too, was immediately inactivated by SAHW containing 50 ppm chlorine in the aqueous phase. These data suggest that SAHW containing 100 ppm chlorine can be used for aerosol disinfection of NDV in farms.

  3. Use of biological assay systems to assess the relative carcinogenic hazards of disinfection by-products.

    PubMed Central

    Bull, R J; Robinson, M; Meier, J R; Stober, J

    1982-01-01

    Other workers have clearly shown that most, if not all, drinking water in the U.S. contains chemicals that possess mutagenic and/or carcinogenic activity by using bacterial and in vitro methods. In the present work, increased numbers of tumors were observed with samples of organic material isolated from 5 U.S. cities administered as tumor initiators in mouse skin initiation/promotion studies. Only in one case was the result significantly different from control. In studies designed to test whether disinfection practice contributes significantly to the tumor initiating activity found in drinking water mixed results have been obtained. In one experiment, water disinfected by chlorination, ozonation or combined chlorine resulted in a significantly greater number of papillomas when compared to nondisinfected water. In two subsequent experiments, where water was obtained from the Ohio River at different times of the year, no evidence of increased initiating activity was observed with any disinfectant. Analysis of water obtained at the comparable times of the year for total organic halogen, and trihalomethane formation revealed a substantial variation in the formation of these products. Considering the problems such variability poses for estimating risks associated with disinfection by-products, a model system which makes use of commercially obtained humic acid as a substrate for chlorination was investigated using the Ames test. Humic and fulvic acids obtained from two surface waters as well as the commercially obtained humic acid were without activity in TA 1535, TA 1537, TA 1538, TA 98 or TA 100 strains of S. typhimurium. Following treatment with a 0.8 molar ratio of chlorine (based on carbon) significant mutagenic activity was observed with all humic and fulvic acid samples. Comparisons of the specific mutagenic activity of the chlorinated products suggests that the commercial material might provide a useful model for studying health hazards associated with

  4. Performance of UV disinfection and the microbial quality of greywater effluent along a reuse system for toilet flushing.

    PubMed

    Friedler, Eran; Gilboa, Yael

    2010-04-01

    This paper examines the microbial quality of treated RBC (Rotating Biological Contactor) and MBR (Membrane Bioreactor) light greywater along a continuous pilot-scale reuse system for toilet flushing, quantifies the efficiency of UV disinfection unit, and evaluates the regrowth potential of selected microorganisms along the system. The UV disinfection unit was found to be very efficient in reducing faecal coliforms and Staphylococcus aureus. On the other hand, its efficiency of inactivation of HPC (Heterotrophic Plate Count) and Pseudomonas aeruginosa was lower. Some regrowth occurred in the reuse system as a result of HPC regrowth which included opportunistic pathogens such as P. aeruginosa. Although the membrane (UF) of the MBR system removed all bacteria from the greywater, bacteria were observed in the reuse system due to "hopping phenomenon." The microbial quality of the disinfected greywater was found to be equal or even better than the microbial quality of "clean" water in toilet bowls flushed with potable water (and used for excretion). Thus, the added health risk associated with reusing the UV-disinfected greywater for toilet flushing (regarding P. aeruginosa and S. aureus), was found to be insignificant. The UV disinfection unit totally removed (100%) the viral indicator (F-RNA phage, host: E. coli F(amp)(+)) injected to the treatment systems simulating transient viral contamination. To conclude, this work contributes to better design of UV disinfection reactors and provides an insight into the long-term behavior of selected microorganisms along on-site greywater reuse systems for toilet flushing.

  5. Disinfection of Spacecraft Potable Water Systems by Photocatalytic Oxidation Using UV-A Light Emitting Diodes

    NASA Technical Reports Server (NTRS)

    Birmele, Michele N.; O'Neal, Jeremy A.; Roberts, Michael S.

    2011-01-01

    Ultraviolet (UV) light has long been used in terrestrial water treatment systems for photodisinfection and the removal of organic compounds by several processes including photoadsorption, photolysis, and photocatalytic oxidation/reduction. Despite its effectiveness for water treatment, UV has not been explored for spacecraft applications because of concerns about the safety and reliability of mercury-containing UV lamps. However, recent advances in ultraviolet light emitting diodes (UV LEDs) have enabled the utilization of nanomaterials that possess the appropriate optical properties for the manufacture of LEDs capable of producing monochromatic light at germicidal wavelengths. This report describes the testing of a commercial-off-the-shelf, high power Nichia UV-A LED (250mW A365nnJ for the excitation of titanium dioxide as a point-of-use (POD) disinfection device in a potable water system. The combination of an immobilized, high surface area photocatalyst with a UV-A LED is promising for potable water system disinfection since toxic chemicals and resupply requirements are reduced. No additional consumables like chemical biocides, absorption columns, or filters are required to disinfect and/or remove potentially toxic disinfectants from the potable water prior to use. Experiments were conducted in a static test stand consisting of a polypropylene microtiter plate containing 3mm glass balls coated with titanium dioxide. Wells filled with water were exposed to ultraviolet light from an actively-cooled UV-A LED positioned above each well and inoculated with six individual challenge microorganisms recovered from the International Space Station (ISS): Burkholderia cepacia, Cupriavidus metallidurans, Methylobacterium fujisawaense, Pseudomonas aeruginosa, Sphingomonas paucimobilis and Wautersia basilensis. Exposure to the Nichia UV-A LED with photocatalytic oxidation resulted in a complete (>7-log) reduction of each challenge bacteria population in <180 minutes of contact

  6. [Inactivation of HIV-1 in human femur heads using a heat disinfection system (Lobator SD-1)].

    PubMed

    von Garrel, T; Knaepler, H; Gürtler, L

    1997-05-01

    The use of allogenic bone transplants in surgery has been greatly diminished owing to the risk of transmitting infectious diseases. This risk can be reduced by the use of a thermal disinfection system (Lobator SD-1). This is achieved by increasing the temperature to 80 degrees C, inactivating a number of bacterial and viral agents. In this study the decay of HIV at high temperature in the Lobator SD-1 was researched. In the center of human femoral heads 100 microliters of a highly concentrated suspension of free and cell-bound HIV (10(10)) was exposed to the thermal process at intervals of 5, 10, 20, 30, 40, 50 and 62 min. For the recultivation HUT-78 cells were used through titration of the virus suspension in ten-fold dilutions over ten dilution steps and incubation up to a maximum of 21 days. Evidence of the virus was checked through observing giant cell formations and quantitative determination of p24 antigen using an Elisa test. Linear virus inactivation was found based upon the time the virus was exposed to heat. After a treatment of 40 min in the disinfection system, total virus inactivation was achieved. The normal disinfection process time using Lobator SD-1 is 92 min. A temperature of 80 degrees C is reached after approximately 45 min. The results prove that this system totally inactivates HIV in human femoral heads.

  7. Evidence of arsenic release promoted by disinfection by-products within drinking-water distribution systems.

    PubMed

    Andra, Syam S; Makris, Konstantinos C; Botsaris, George; Charisiadis, Pantelis; Kalyvas, Harris; Costa, Costas N

    2014-02-15

    Changes in disinfectant type could trigger a cascade of reactions releasing pipe-anchored metals/metalloids into finished water. However, the effect of pre-formed disinfection by-products on the release of sorbed contaminants (arsenic-As in particular) from drinking water distribution system pipe scales remains unexplored. A bench-scale study using a factorial experimental design was performed to evaluate the independent and interaction effects of trihalomethanes (TTHM) and haloacetic acids (HAA) on arsenic (As) release from either scales-only or scale-biofilm conglomerates (SBC) both anchored on asbestos/cement pipe coupons. A model biofilm (Pseudomonas aeruginosa) was allowed to grow on select pipe coupons prior experimentation. Either TTHM or HAA individual dosing did not promote As release from either scales only or SBC, detecting <6 μg AsL(-1) in finished water. In the case of scales-only coupons, the combination of the highest spike level of TTHM and HAA significantly (p<0.001) increased dissolved and total As concentrations to levels up to 16 and 95 μg L(-1), respectively. Similar treatments in the presence of biofilm (SBC) resulted in significant (p<0.001) increase in dissolved and total recoverable As up to 20 and 47 μg L(-1), respectively, exceeding the regulatory As limit. Whether or not, our laboratory-based results truly represent mechanisms operating in disinfected finished water in pipe networks remains to be investigated in the field.

  8. Evaluation of techniques for control of disinfection by-products: a pilot study.

    PubMed

    Nnadi, Fidelia N; Hernandez, Migdalia; Fulkerson, Mark

    2004-01-01

    The purpose of this study was to evaluate the effects of various treatment processes as they relate to the development of disinfection by-products (DBPs). At an existing municipal water supply, several tests were performed, including: air-stripping, potassium permanganate (KMnO4) addition, pH adjustment, evaluation of corrosion control inhibitors, final disinfection, and granular activated carbon (CAC) filtration. Several HAAs were shown to increase at higher pH. The use of air stripping greatly reduced the required amount of chlorine disinfectant. Air stripping, permanganate addition, and chloramination reduced DBPs below 20 microg/L. Stiles-Kem 7840 addition effectively controlled lead and copper concentrations in the distribution system. The use of chloramination its a secondary disinfectant is recommended to meet stage 1 of the disinfection by-product rule.

  9. Efficacy of different disinfectant systems on alginate and addition silicone impression materials of Indian and international origin: a comparative evaluation.

    PubMed

    Samra, R K; Bhide, S V

    2010-09-01

    Study was planned to evaluate the efficacy of commonly used disinfectants and to study qualitatively and quantitatively the persistence of microflora on the untreated (control group) and the disinfected impression surface after 24 h. Disinfectant systems used were immersion systems like glutaraldehyde, sodium hypochlorite and the ultraviolet chamber. The effect of disinfectant on most commonly used Indian impression materials was carried out in this study and results compared with the most commonly used foreign brands for irreversible hydrocolloid and addition silicone. Impressions were made of 25 healthy volunteers. These were disinfected and incubated in an incubator for 24 h at 37°C for aerobic organisms. The inoculation in nutrient media was done to test the viability of microorganisms that can persist after rinsing and disinfection of the impression surface. The colony forming units were counted and compared with that of control group. Control group of all the impression material samples showed growth of Streptococcus viridans, Diphtheroids, Streptococcus pneumoniae to a greater extent. The growth of Candida albicans, Pseudomonas aerugenosa and Staphyloccus albus was present in all the groups but to a lesser extent. The persistence of the microflora on the impression surface of both the studied brands was similar but the concentration of organisms in the alginate control group was two folds as compared to addition silicone group. Use of ultraviolet chamber gave better results compared to the studied immersion systems. All the disinfection systems were effective in reducing the microbial load with ultraviolet chamber as the most effective. PMID:21886411

  10. Testing the Carcinogenic Potential of Water Disinfectant Byproducts in a Human Colon Mucosal Culture System

    EPA Science Inventory

    Epidemiological studies have linked the consumption of disinfected surface waters to an increased risk of colorectal cancer. Approximately 600 disinfection byproducts (DBPs) have been identified for a number of disinfectants currently in use. An in-depth mechanism-based structure...

  11. Decrease of time for pathogen inactivation in alkaline disinfection systems using pressure.

    PubMed

    Fitzmorris, Kari B; Reimers, Robert S; Oleszkiewicz, Jan A; Little, M Dale

    2007-04-01

    From field studies conducted by Tulane University (New Orleans, Louisiana), efficiency of advanced alkaline disinfection in closed systems was found to depend on ammonia concentration, pH, exposure time, temperature, total solids content, pretreatment storage time, and mixing effectiveness. In this study of a closed alkaline system, an additional pathogen stressor pressure was tested. The effect of the alkaline dosing has been assessed for dewatered raw and aerobically and anaerobically digested municipal sludge cake that produce un-ionized ammonia at concentrations of 0.05 to 2% on a dry-weight basis. Inactivation of Ascaris suum eggs increased from 50 to 99% as the temperature was increased from 40 to 55 degrees C, thus achieving Class A levels. The systems studied were compared with an alkaline process operated under open conditions, which limited the concentrations of ammonia available because of Henry's Law. Under a closed pressurized system, the effect of un-ionized ammonia was greatly increased, and the resulting time required for inactivation was reduced from hours or days to minutes. In the next few years, it is expected that alkaline disinfection of biosolids will be optimized in relation to the factors stated above, at much lower doses of the alkaline agents. The closed-system alkaline processes that will be developed will be more energy-efficient, cost-effective, and have full control of potential odorous emissions.

  12. System interactions of air pollutants

    SciTech Connect

    Pierson, W.E. )

    1992-06-01

    The impact of system interactions and simultaneous or sequential exposure to various air pollutants, both man-made and natural ones, requires greater concern in the interpretation of the total adverse impact of various air pollutants. It is clear that there are highly significant system interactions with exposure to various air pollutants, and these must be considered very carefully in the evaluation of their adverse health effects.

  13. Air conditioning system

    DOEpatents

    Lowenstein, Andrew; Miller, Jeffrey; Gruendeman, Peter; DaSilva, Michael

    2005-02-01

    An air conditioner comprises a plurality of plates arranged in a successively stacked configuration with portions thereof having a spaced apart arrangement, and defining between successive adjacent pairs of plates at the spaced apart portions a first and second series of discrete alternating passages wherein a first air stream is passed through the first series of passages and a second air stream is passed through the second series of passages; and said stacked configuration of plates forming integrally therewith a liquid delivery means for delivering from a source a sufficient quantity of a liquid to the inside surfaces of the first series of fluid passages in a manner which provides a continuous flow of the liquid from a first end to a second end of the plurality of plates while in contact with the first air stream.

  14. Hybrid membrane contactor system for creating semi-breathing air

    NASA Astrophysics Data System (ADS)

    Timofeev, D. V.

    2012-02-01

    Typically, the equipment to create an artificial climate does not involve changing the composition of the respiratory air. In particular in medical institutions assumes the existence of plant of artificial climate and disinfection in operating rooms and intensive care wards. The use of a hybrid membrane-absorption systems for the generation of artificial atmospheres are improving the respiratory system, blood is enriched or depleted of various gases, resulting in increased stamina, there is a better, faster or slower metabolism, improves concentration and memory. Application of the system contributes to easy and rapid recovery after the operation. By adding a special component, with drug activity, air ionization, and adjust its composition, you can create a special, more favorable for patients with the atmosphere. These factors allow for the treatment and rehabilitation of patients and reduce mortality of heavy patients.

  15. Fundamentals of air quality systems

    SciTech Connect

    Noll, K.E.

    1999-08-01

    The book uses numerous examples to demonstrate how basic design concepts can be applied to the control of air emissions from industrial sources. It focuses on the design of air pollution control devices for the removal of gases and particles from industrial sources, and provides detailed, specific design methods for each major air pollution control system. Individual chapters provide design methods that include both theory and practice with emphasis on the practical aspect by providing numerous examples that demonstrate how air pollution control devices are designed. Contents include air pollution laws, air pollution control devices; physical properties of air, gas laws, energy concepts, pressure; motion of airborne particles, filter and water drop collection efficiency; fundamentals of particulate emission control; cyclones; fabric filters; wet scrubbers; electrostatic precipitators; control of volatile organic compounds; adsorption; incineration; absorption; control of gaseous emissions from motor vehicles; practice problems (with solutions) for the P.E. examination in environmental engineering. Design applications are featured throughout.

  16. Assessing microbiological water quality in drinking water distribution systems with disinfectant residual using flow cytometry.

    PubMed

    Gillespie, Simon; Lipphaus, Patrick; Green, James; Parsons, Simon; Weir, Paul; Juskowiak, Kes; Jefferson, Bruce; Jarvis, Peter; Nocker, Andreas

    2014-11-15

    Flow cytometry (FCM) as a diagnostic tool for enumeration and characterization of microorganisms is rapidly gaining popularity and is increasingly applied in the water industry. In this study we applied the method to obtain a better understanding of total and intact cell concentrations in three different drinking water distribution systems (one using chlorine and two using chloramines as secondary disinfectants). Chloramine tended to result in lower proportions of intact cells than chlorine over a wider residual range, in agreement with existing knowledge that chloramine suppresses regrowth more efficiently. For chlorinated systems, free chlorine concentrations above 0.5 mg L(-1) were found to be associated with relatively low proportions of intact cells, whereas lower disinfectant levels could result in substantially higher percentages of intact cells. The threshold for chlorinated systems is in good agreement with guidelines from the World Health Organization. The fact that the vast majority of samples failing the regulatory coliform standard also showed elevated proportions of intact cells suggests that this parameter might be useful for evaluating risk of failure. Another interesting parameter for judging the microbiological status of water, the biological regrowth potential, greatly varied among different finished waters providing potential help for investment decisions. For its measurement, a simple method was introduced that can easily be performed by water utilities with FCM capability.

  17. [Experience of organization of flushing and disinfection of centralized system of hot water supply in town Verkhnyaya Pyshma after its colonization by Legionella].

    PubMed

    Onishchenko, G G; Nikonov, B I; Gurvich, V B; Akramov, R L; Vlasov, I A; Belov, E A; Shatilo, S V; Mustafina, N V; Kaletnik, V P

    2008-01-01

    Causes of outbreak incidence of pneumonia due to Legionella infection in population of Verkhnyaya Pyshma as well as factors promoting colonization of town's hot water supply system by Legionella were discussed. Experience of organization of flushing and disinfection of hot water supply system was described, effectiveness of different methods of disinfection was evaluated.

  18. Photocatalytic equipment with nitrogen-doped titanium dioxide for air cleaning and disinfecting

    NASA Astrophysics Data System (ADS)

    Son Le, Thanh; Buu Ngo, Quoc; Dung Nguyen, Viet; Chau Nguyen, Hoai; Hien Dao, Trong; Tin Tran, Xuan; Kabachkov, E. N.; Balikhin, I. L.

    2014-03-01

    Nitrogen-doped TiO2 nanoparticle photocatalysts were synthesized by a sol-gel procedure using tetra-n-butyl orthotitanate as a titanium precursor and urea as a nitrogen source. Systematic studies for the preparation parameters and their impact on the material's structure were carried out by multiple techniques: thermogravimetric and differential scanning calorimetric analysis, x-ray diffraction, scanning electron microscope, transmission electron microscopy, energy dispersive x-ray spectroscopy and UV-Vis diffuse reflectance spectrophotometry showed that the nitrogen-doped TiO2 calcined at 500 °C for 3 h exhibited a spherical form with a particle size about 15-20 nm and crystal phase presented a mixture of 89.12% anatase. The obtained product was deposited on a porous quartz tube (D = 74 mm l = 418 mm) to manufacture an air photocatalytic cleaner as a prototype of the TIOKRAFT company's equipment. The created air cleaner was able to remove 60% of 10 ppm acetone within 390 min and degrade 98.5% of bacteria (total aerobic bacteria and fungi, 300 cfu m-3) within 120 min in a 10 m3 box. These photodegradation activities of N-TiO2 are higher than that of the commercial nano-TiO2 (Skyspring Inc., USA, particle size of 5-10 nm).

  19. Advanced air revitalization system testing

    NASA Technical Reports Server (NTRS)

    Heppner, D. B.; Hallick, T. M.; Schubert, F. H.

    1983-01-01

    A previously developed experimental air revitalization system was tested cyclically and parametrically. One-button startup without manual interventions; extension by 1350 hours of tests with the system; capability for varying process air carbon dioxide partial pressure and humidity and coolant source for simulation of realistic space vehicle interfaces; dynamic system performance response on the interaction of the electrochemical depolarized carbon dioxide concentrator, the Sabatier carbon dioxide reduction subsystem, and the static feed water electrolysis oxygen generation subsystem, the carbon dioxide concentrator module with unitized core technology for the liquid cooled cell; and a preliminary design for a regenerative air revitalization system for the space station are discussed.

  20. Action spectra for validation of pathogen disinfection in medium-pressure ultraviolet (UV) systems.

    PubMed

    Beck, Sara E; Wright, Harold B; Hargy, Thomas M; Larason, Thomas C; Linden, Karl G

    2015-03-01

    Ultraviolet (UV) reactors used for disinfecting water and wastewater must be validated and monitored over time. The validation process requires understanding the photochemical properties of the pathogens of concern and the challenge microorganisms used to represent them. Specifically for polychromatic UV systems, the organisms' dose responses to UV light and their sensitivity across the UV spectrum must be known. This research measured the UV spectral sensitivity, called action spectra, of Cryptosporidium parvum, and MS2, T1UV, Q Beta, T7, and T7m Coliphages, as well as Bacillus pumilus spores. A tunable laser from the National Institute of Standards and Technology was used to isolate single UV wavelengths at 10 nm intervals between 210 and 290 nm. Above 240 nm, all bacteria and viruses tested exhibited a relative peak sensitivity between 260 and 270 nm. Of the coliphage, MS2 exhibited the highest relative sensitivity below 240 nm, relative to its sensitivity at 254 nm, followed by Q Beta, T1UV, T7m and T7 coliphage. B. pumilus spores were more sensitive to UV light at 220 nm than any of the coliphage. These spectra are required for calculating action spectra correction factors for medium pressure UV system validation, for matching appropriate challenge microorganisms to pathogens, and for improving UV dose monitoring. Additionally, understanding the dose response of these organisms at multiple wavelengths can improve polychromatic UV dose calculations and enable prediction of pathogen inactivation from wavelength-specific disinfection technologies such as UV light emitting diodes (LEDs).

  1. [Effect of ammonia-oxidizing bacteria (AOB) on chloraminated disinfection attenuation in drinking water distribution system].

    PubMed

    Bai, Xiao-Hui; Cai, Yun-Long; Zhou, Bin-Hui; Zhi, Xing-Hua

    2009-06-15

    The growth of microbe and formation of biofilm in water distribution system were important factors affecting the security of water quality. The number of ammonia-oxidizing bacteria (AOB) in biofilm of a chloraminated drinking water distribution system in Shanghai was detected by MPN-Griess method, and the relations among AOB, nitrification and chloraminated disinfection were analyzed. Meanwhile, the effects of AOB on chloraminated disinfection fastness and attenuation by simulation experiment were studied. The result indicated that the number of ammonia-oxidizing bacteria in pipe biofilm was between 1.0 x 10(2)-4.3 x 10(5) MPN/g dry biofilm. Correlation coefficients of AOB with ammonia, nitrite and nitrate were -0.563, 0.603 and -0.563. Correlation coefficients of AOB with total chlorine and mono-chloramine were -0.659 and -0.571. Fastness of AOB to chloramine was higher than heterotrophic bacteria and AOB can deplete more chloramine than HPC.

  2. Action spectra for validation of pathogen disinfection in medium-pressure ultraviolet (UV) systems.

    PubMed

    Beck, Sara E; Wright, Harold B; Hargy, Thomas M; Larason, Thomas C; Linden, Karl G

    2015-03-01

    Ultraviolet (UV) reactors used for disinfecting water and wastewater must be validated and monitored over time. The validation process requires understanding the photochemical properties of the pathogens of concern and the challenge microorganisms used to represent them. Specifically for polychromatic UV systems, the organisms' dose responses to UV light and their sensitivity across the UV spectrum must be known. This research measured the UV spectral sensitivity, called action spectra, of Cryptosporidium parvum, and MS2, T1UV, Q Beta, T7, and T7m Coliphages, as well as Bacillus pumilus spores. A tunable laser from the National Institute of Standards and Technology was used to isolate single UV wavelengths at 10 nm intervals between 210 and 290 nm. Above 240 nm, all bacteria and viruses tested exhibited a relative peak sensitivity between 260 and 270 nm. Of the coliphage, MS2 exhibited the highest relative sensitivity below 240 nm, relative to its sensitivity at 254 nm, followed by Q Beta, T1UV, T7m and T7 coliphage. B. pumilus spores were more sensitive to UV light at 220 nm than any of the coliphage. These spectra are required for calculating action spectra correction factors for medium pressure UV system validation, for matching appropriate challenge microorganisms to pathogens, and for improving UV dose monitoring. Additionally, understanding the dose response of these organisms at multiple wavelengths can improve polychromatic UV dose calculations and enable prediction of pathogen inactivation from wavelength-specific disinfection technologies such as UV light emitting diodes (LEDs). PMID:25506761

  3. Air ejector augmented compressed air energy storage system

    DOEpatents

    Ahrens, Frederick W.; Kartsounes, George T.

    1980-01-01

    Energy is stored in slack demand periods by charging a plurality of underground reservoirs with air to the same peak storage pressure, during peak demand periods throttling the air from one storage reservoir into a gas turbine system at a constant inlet pressure until the air pressure in the reservoir falls to said constant inlet pressure, thereupon permitting air in a second reservoir to flow into said gas turbine system while drawing air from the first reservoir through a variable geometry air ejector and adjusting said variable geometry air ejector, said air flow being essentially at the constant inlet pressure of the gas turbine system.

  4. Air ejector augmented compressed air energy storage system

    DOEpatents

    Ahrens, F.W.; Kartsounes, G.T.

    Energy is stored in slack demand periods by charging a plurality of underground reservoirs with air to the same peak storage pressure, during peak demand periods throttling the air from one storage reservoir into a gas turbine system at a constant inlet pressure until the air presure in the reservoir falls to said constant inlet pressure, thereupon permitting air in a second reservoir to flow into said gas turbine system while drawing air from the first reservoir through a variable geometry air ejector and adjusting said variable geometry air ejector, said air flow being essentially at the constant inlet pressure of the gas turbine system.

  5. Air Pollution Surveillance Systems

    ERIC Educational Resources Information Center

    Morgan, George B.; And Others

    1970-01-01

    Describes atmospheric data monitoring as part of total airpollution control effort. Summarizes types of gaseous, liquid and solid pollutants and their sources; contrast between urban and rural environmental air quality; instrumentation to identify pollutants; and anticipated new non-wet chemical physical and physiochemical techniques tor cetection…

  6. Disinfection of bacterial biofilms in pilot-scale cooling tower systems

    PubMed Central

    Liu, Yang; Zhang, Wei; Sileika, Tadas; Warta, Richard; Cianciotto, Nicholas P.; Packman, Aaron I.

    2015-01-01

    The impact of continuous chlorination and periodic glutaraldehyde treatment on planktonic and biofilm microbial communities was evaluated in pilot-scale cooling towers operated continuously for 3 months. The system was operated at a flow rate of 10,080 l day−1. Experiments were performed with a well-defined microbial consortium containing three heterotrophic bacteria: Pseudomonas aeruginosa, Klebsiella pneumoniae and Flavobacterium sp. The persistence of each species was monitored in the recirculating cooling water loop and in biofilms on steel and PVC coupons in the cooling tower basin. The observed bacterial colonization in cooling towers did not follow trends in growth rates observed under batch conditions and, instead, reflected differences in the ability of each organism to remain attached and form biofilms under the high-through flow conditions in cooling towers. Flavobacterium was the dominant organism in the community, while P. aeruginosa and K. pneumoniae did not attach well to either PVC or steel coupons in cooling towers and were not able to persist in biofilms. As a result, the much greater ability of Flavobacterium to adhere to surfaces protected it from disinfection, whereas P. aeruginosa and K. pneumoniae were subject to rapid disinfection in the planktonic state. PMID:21547755

  7. Nitrogenous disinfection byproducts in English drinking water supply systems: Occurrence, bromine substitution and correlation analysis.

    PubMed

    Bond, Tom; Templeton, Michael R; Mokhtar Kamal, Nurul Hana; Graham, Nigel; Kanda, Rakesh

    2015-11-15

    Despite the recent focus on nitrogenous disinfection byproducts in drinking water, there is limited occurrence data available for many species. This paper analyses the occurrence of seven haloacetonitriles, three haloacetamides, eight halonitromethanes and cyanogen chloride in 20 English drinking water supply systems. It is the first survey of its type to compare bromine substitution factors (BSFs) between the haloacetamides and haloacetonitriles. Concentrations of the dihalogenated haloacetonitriles and haloacetamides were well correlated. Although median concentrations of these two groups were lower in chloraminated than chlorinated surface waters, median BSFs for both in chloraminated samples were approximately double those in chlorinated samples, which is significant because of the higher reported toxicity of the brominated species. Furthermore, median BSFs were moderately higher for the dihalogenated haloacetamides than for the haloacetonitriles. This indicates that, while the dihalogenated haloacetamides were primarily generated from hydrolysis of the corresponding haloacetonitriles, secondary formation pathways also contributed. Median halonitromethane concentrations were remarkably unchanging for the different types of disinfectants and source waters: 0.1 μg · mgTOC(-1) in all cases. Cyanogen chloride only occurred in a limited number of samples, yet when present its concentrations were higher than the other N-DBPs. Concentrations of cyanogen chloride and the sum of the halonitromethanes were not correlated with any other DBPs.

  8. Disinfection of bacterial biofilms in pilot-scale cooling tower systems.

    PubMed

    Liu, Yang; Zhang, Wei; Sileika, Tadas; Warta, Richard; Cianciotto, Nicholas P; Packman, Aaron I

    2011-04-01

    The impact of continuous chlorination and periodic glutaraldehyde treatment on planktonic and biofilm microbial communities was evaluated in pilot-scale cooling towers operated continuously for 3 months. The system was operated at a flow rate of 10,080 l day(-1). Experiments were performed with a well-defined microbial consortium containing three heterotrophic bacteria: Pseudomonas aeruginosa, Klebsiella pneumoniae and Flavobacterium sp. The persistence of each species was monitored in the recirculating cooling water loop and in biofilms on steel and PVC coupons in the cooling tower basin. The observed bacterial colonization in cooling towers did not follow trends in growth rates observed under batch conditions and, instead, reflected differences in the ability of each organism to remain attached and form biofilms under the high-through flow conditions in cooling towers. Flavobacterium was the dominant organism in the community, while P. aeruginosa and K. pneumoniae did not attach well to either PVC or steel coupons in cooling towers and were not able to persist in biofilms. As a result, the much greater ability of Flavobacterium to adhere to surfaces protected it from disinfection, whereas P. aeruginosa and K. pneumoniae were subject to rapid disinfection in the planktonic state.

  9. Disinfection of bacterial biofilms in pilot-scale cooling tower systems.

    PubMed

    Liu, Yang; Zhang, Wei; Sileika, Tadas; Warta, Richard; Cianciotto, Nicholas P; Packman, Aaron I

    2011-04-01

    The impact of continuous chlorination and periodic glutaraldehyde treatment on planktonic and biofilm microbial communities was evaluated in pilot-scale cooling towers operated continuously for 3 months. The system was operated at a flow rate of 10,080 l day(-1). Experiments were performed with a well-defined microbial consortium containing three heterotrophic bacteria: Pseudomonas aeruginosa, Klebsiella pneumoniae and Flavobacterium sp. The persistence of each species was monitored in the recirculating cooling water loop and in biofilms on steel and PVC coupons in the cooling tower basin. The observed bacterial colonization in cooling towers did not follow trends in growth rates observed under batch conditions and, instead, reflected differences in the ability of each organism to remain attached and form biofilms under the high-through flow conditions in cooling towers. Flavobacterium was the dominant organism in the community, while P. aeruginosa and K. pneumoniae did not attach well to either PVC or steel coupons in cooling towers and were not able to persist in biofilms. As a result, the much greater ability of Flavobacterium to adhere to surfaces protected it from disinfection, whereas P. aeruginosa and K. pneumoniae were subject to rapid disinfection in the planktonic state. PMID:21547755

  10. Cold air systems: Sleeping giant

    SciTech Connect

    MacCracken, C.D. )

    1994-04-01

    This article describes how cold air systems help owners increase the profits from their buildings by reducing electric costs and improving indoor air quality through lower relative humidity levels. Cold air distribution involves energy savings, cost savings, space savings, greater comfort, cleaner air, thermal storage, tighter ducting, coil redesign, lower relative humidities, retrofitting, and improved indoor air quality (IAQ). It opens a door for architects, engineers, owners, builders, environmentalists, retrofitters, designers, occupants, and manufacturers. Three things have held up cold air's usage: multiple fan-powered boxes that ate up the energy savings of primary fans. Cold air room diffusers that provided inadequate comfort. Condensation from ducts, boxes, and diffusers. Such problems have been largely eliminated through research and development by utilities and manufacturers. New cold air diffusers no longer need fan powered boxes. It has also been found that condensation is not a concern so long as the ducts are located in air conditioned space, such as drop ceilings or central risers, where relative humidity falls quickly during morning startup.

  11. 40 CFR 141.532 - How does my system develop a disinfection profile and when must it begin?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false How does my system develop a disinfection profile and when must it begin? 141.532 Section 141.532 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS...

  12. Occurrence and Spatial and Temporal Variations of Disinfection By-Products in the Water and Air of Two Indoor Swimming Pools

    PubMed Central

    Catto, Cyril; Sabrina, Simard; Ginette, Charest-Tardif; Manuel, Rodriguez; Robert, Tardif

    2012-01-01

    In order to improve disinfection by-product (DBP) exposure assessment, this study was designed to document both water and air levels of these chemical contaminants in two indoor swimming pools and to analyze their within-day and day-to-day variations in both of them. Intensive sampling was carried out during two one-week campaigns to measure trihalomethanes (THMs) and chloramines (CAMs) in water and air, and haloacetic acids (HAAs) in water several times daily. Water samples were systematically collected at three locations in each pool and air samples were collected at various heights around the pool and in other rooms (e.g., changing room) in the buildings. In addition, the ability of various models to predict air concentrations from water was tested using this database. No clear trends, but actual variations of contamination levels, appeared for both water and air according to the sampling locations and times. Likewise, the available models resulted in realistic but imprecise estimates of air contamination levels from water. This study supports the recommendation that suitable minimal air and water sampling should be carried out in swimming pools to assess exposure to DBPs. PMID:23066383

  13. Air support facilities. [interface between air and surface transportation systems

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Airports are discussed in terms of the interface between the ground and air for transportation systems. The classification systems, design, facilities, administration, and operations of airports are described.

  14. A pulsed light system for the disinfection of flow through water in the presence of inorganic contaminants.

    PubMed

    Garvey, Mary; Rowan, Neil

    2015-06-01

    The use of ultraviolet (UV) light for water disinfection has become increasingly popular due to on-going issues with drinking water and public health. Pulsed UV light has proved to be an effective form of inactivating a range of pathogens including parasite species. However, there are limited data available on the use of pulsed UV light for the disinfection of flowing water in the absence or presence of inorganic contaminants commonly found in water sources. Here, we report on the inactivation of test species including Bacillus endospores following pulsed UV treatment as a flow through system. Significant levels of inactivation were obtained for both retention times tested. The presence of inorganic contaminants iron and/or manganese did affect the rate of disinfection, predominantly resulting in an increase in the levels of inactivation at certain UV doses. The findings of this study suggest that pulsed UV light may provide a method of water disinfection as it successfully inactivated bacterial cells and bacterial endospores in the absence and presence of inorganic contaminants.

  15. Magnus air turbine system

    DOEpatents

    Hanson, Thomas F.

    1982-01-01

    A Magnus effect windmill for generating electrical power is disclosed. A large nacelle-hub mounted pivotally (in Azimuth) atop a support tower carries, in the example disclosed, three elongated barrels arranged in a vertical plane and extending symmetrically radially outwardly from the nacelle. The system provides spin energy to the barrels by internal mechanical coupling in the proper sense to cause, in reaction to an incident wind, a rotational torque of a predetermined sense on the hub. The rotating hub carries a set of power take-off rollers which ride on a stationary circular track in the nacelle. Shafts carry the power, given to the rollers by the wind driven hub, to a central collector or accumulator gear assembly whose output is divided to drive the spin mechanism for the Magnus barrels and the main electric generator. A planetary gear assembly is interposed between the collector gears and the spin mechanism functioning as a differential which is also connected to an auxiliary electric motor whereby power to the spin mechanism may selectively be provided by the motor. Generally, the motor provides initial spin to the barrels for start-up after which the motor is braked and the spin mechanism is driven as though by a fixed ratio coupling from the rotor hub. During high wind or other unusual conditions, the auxiliary motor may be unbraked and excess spin power may be used to operate the motor as a generator of additional electrical output. Interposed between the collector gears of the rotating hub and the main electric generator is a novel variable speed drive-fly wheel system which is driven by the variable speed of the wind driven rotor and which, in turn, drives the main electric generator at constant angular speed. Reference is made to the complete specification for disclosure of other novel aspects of the system such as, for example, the aerodynamic and structural aspects of the novel Magnus barrels as well as novel gearing and other power coupling

  16. Disinfectants used for environmental disinfection and new room decontamination technology.

    PubMed

    Rutala, William A; Weber, David J

    2013-05-01

    Environmental contamination plays an important role in the transmission of several key health care-associated pathogens. Effective and thorough cleaning/disinfecting of the patient environment is essential. Room decontamination units (such as ultraviolet-C and hydrogen peroxide systems) aid in reducing environmental contamination after terminal room cleaning and disinfection.

  17. Shift in the microbial ecology of a hospital hot water system following the introduction of an on-site monochloramine disinfection system.

    PubMed

    Baron, Julianne L; Vikram, Amit; Duda, Scott; Stout, Janet E; Bibby, Kyle

    2014-01-01

    Drinking water distribution systems, including premise plumbing, contain a diverse microbiological community that may include opportunistic pathogens. On-site supplemental disinfection systems have been proposed as a control method for opportunistic pathogens in premise plumbing. The majority of on-site disinfection systems to date have been installed in hospitals due to the high concentration of opportunistic pathogen susceptible occupants. The installation of on-site supplemental disinfection systems in hospitals allows for evaluation of the impact of on-site disinfection systems on drinking water system microbial ecology prior to widespread application. This study evaluated the impact of supplemental monochloramine on the microbial ecology of a hospital's hot water system. Samples were taken three months and immediately prior to monochloramine treatment and monthly for the first six months of treatment, and all samples were subjected to high throughput Illumina 16S rRNA region sequencing. The microbial community composition of monochloramine treated samples was dramatically different than the baseline months. There was an immediate shift towards decreased relative abundance of Betaproteobacteria, and increased relative abundance of Firmicutes, Alphaproteobacteria, Gammaproteobacteria, Cyanobacteria and Actinobacteria. Following treatment, microbial populations grouped by sampling location rather than sampling time. Over the course of treatment the relative abundance of certain genera containing opportunistic pathogens and genera containing denitrifying bacteria increased. The results demonstrate the driving influence of supplemental disinfection on premise plumbing microbial ecology and suggest the value of further investigation into the overall effects of premise plumbing disinfection strategies on microbial ecology and not solely specific target microorganisms. PMID:25033448

  18. Steerable percussion air drilling system

    SciTech Connect

    Bui, H.D.; Meyers, J.A.; Yost, A.B. II

    1998-12-31

    By increasing penetration rates and bit life, especially in hard formations, the use of down-hole air hammers in the oil field has significantly reduced drilling costs in the Northeast US and West Texas. Unfortunately, drilling by this percussion method has been limited mostly to straight hole applications. This paper presents a new concept of a percussion drilling tool which performs both the function of a down-hole hammer as well as that of a down-hole motor. Such a drilling tool, being introduced here as Steerable Percussion Air Drilling System (SPADS), eliminates the necessity to rotate the drill string and, consequently, enables the use of down-hole air hammers to drill directional wells.

  19. Selection of an ultraviolet disinfection system for a municipal wastewater treatment plant.

    PubMed

    Kang, S J; Allbaugh, T A; Reynhout, J W; Erickson, T L; Olmstead, K P; Thomas, L; Thomas, P

    2004-01-01

    As part of an expansion to an average flow of 45.9 million gallons per day (174 mld), the Ypsilanti Community Utilities Authority wastewater treatment plant in the State of Michigan, USA, elected to install ultraviolet disinfection as a replacement for the existing chlorination process. This paper presents a unique methodology used in selecting the best system based on not only the life cycle costs, and O & M considerations but also the participation of the stakeholders. The Team members consisted of representatives of all departments at the Authority, and these Team members made the decision. The Team evaluated all criteria in the office, which was followed by verification at selected sites with similar types of equipment. The selected equipment then was pilot tested for validation of the dose-kill relationship under normal operation and also under reduced irradiation conditions. A low-pressure, high intensity system was selected, based on life-cycle cost, reliability, safety, and ease of operation. This paper describes the unique methodologies used in making that decision. The full-scale system is scheduled for start-up in Spring 2003.

  20. Effects of disinfection on Legionella spp., eukarya, and biofilms in a hot water system.

    PubMed

    Farhat, Maha; Moletta-Denat, Marina; Frère, Jacques; Onillon, Séverine; Trouilhé, Marie-Cécile; Robine, Enric

    2012-10-01

    Legionella species are frequently detected in hot water systems, attached to the surface as a biofilm. In this work, the dynamics of Legionella spp. and diverse bacteria and eukarya associated together in the biofilm, coming from a pilot scale 1 system simulating a real hot water system, were investigated throughout 6 months after two successive heat shock treatments followed by three successive chemical treatments. Community structure was assessed by a fingerprint technique, single-strand conformation polymorphism (SSCP). In addition, the diversity and dynamics of Legionella and eukarya were investigated by small-subunit (SSU) ribosomal cloning and sequencing. Our results showed that pathogenic Legionella species remained after the heat shock and chemical treatments (Legionella pneumophila and Legionella anisa, respectively). The biofilm was not removed, and the bacterial community structure was transitorily affected by the treatments. Moreover, several amoebae had been detected in the biofilm before treatments (Thecamoebae sp., Vannella sp., and Hartmanella vermiformis) and after the first heat shock treatment, but only H. vermiformis remained. However, another protozoan affiliated with Alveolata, which is known as a host cell for Legionella, dominated the eukaryal species after the second heat shock and chemical treatment tests. Therefore, effective Legionella disinfection may be dependent on the elimination of these important microbial components. We suggest that eradicating Legionella in hot water networks requires better study of bacterial and eukaryal species associated with Legionella in biofilms.

  1. ENVIRONMENTAL TECHNOLOGY VERIFICATION: JOINT (NSF-EPA) VERIFICATION STATEMENT AND REPORT FOR THE UV DISINFECTION OF SECONDARY EFFLUENTS, SUNTEC, INC. MODEL LPX200 DISINFECTION SYSTEM - 03/09/WQPC-SWP

    EPA Science Inventory

    Verification testing of the SUNTEC LPX200 UV Disinfection System to develop the UV delivered dose flow relationship was conducted at the Parsippany-Troy Hills wastewater treatment plant test site in Parsippany, New Jersey. Two lamp modules were mounted parallel in a 6.5-meter lon...

  2. Optical air data systems and methods

    NASA Technical Reports Server (NTRS)

    Caldwell, Loren M. (Inventor); Tang, Shoou-yu (Inventor); O'Brien, Martin (Inventor)

    2010-01-01

    Systems and methods for sensing air outside a moving aircraft are presented. In one embodiment, a system includes a laser for generating laser energy. The system also includes one or more transceivers for projecting the laser energy as laser radiation to the air. Subsequently, each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines one or more air parameters based on the scattered laser radiation. Such air parameters may include air speed, air pressure, air temperature and aircraft orientation angle, such as yaw, angle of attack and sideslip.

  3. Optical air data systems and methods

    NASA Technical Reports Server (NTRS)

    Caldwell, Loren M. (Inventor); O'Brien, Martin J. (Inventor); Weimer, Carl S. (Inventor); Nelson, Loren D. (Inventor)

    2005-01-01

    Systems and methods for sensing air outside a moving aircraft are presented. In one embodiment, a system includes a laser for generating laser energy. The system also includes one or more transceivers for projecting the laser energy as laser radiation to the air. Subsequently, each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines one or more air parameters based on the scattered laser radiation. Such air parameters may include air speed, air pressure, air temperature and aircraft orientation angle, such as yaw, angle of attack and sideslip.

  4. Optical air data systems and methods

    NASA Technical Reports Server (NTRS)

    Caldwell, Loren M. (Inventor); O'Brien, Martin J. (Inventor); Weimer, Carl S. (Inventor); Nelson, Loren D. (Inventor)

    2008-01-01

    Systems and methods for sensing air outside a moving aircraft are presented. In one embodiment, a system includes a laser for generating laser energy. The system also includes one or more transceivers for projecting the laser energy as laser radiation to the air. Subsequently, each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines one or more air parameters based on the scattered laser radiation. Such air parameters may include air speed, air pressure, air temperature and aircraft orientation angle, such as yaw, angle of attack and sideslip.

  5. Air control system providing healthful enclosed environment

    SciTech Connect

    Rhodes, J.A.

    1991-08-27

    This patent describes an environmentally controlled building. It comprises an outer wall defining an outer building perimeter and having at least one fenestration therethrough for passage of personnel; a roof supported by and cooperating with the outer wall to define a building exterior and interior; and an environmental control system for controlling the environment within the building interior, the environmental control system including a heating and air conditioning unit, having an air inlet, for controlling the temperature of air drawing into the air control system; a humidity control unit, having an inlet connected to the heating and air conditioning unit, for controlling the humidity of air within the air control system; an air blower for forcing air from the environmental control system into the building interior; and an air filtering system having an inlet connected to the humidity control unit and an outlet connected to the blower.

  6. Disinfection of Spacecraft Potable Water Systems by Passivation with Ionic Silver

    NASA Technical Reports Server (NTRS)

    Birmele, Michele N.; McCoy, LaShelle e.; Roberts, Michael S.

    2011-01-01

    Microbial growth is common on wetted surfaces in spacecraft environmental control and life support systems despite the use of chemical and physical disinfection methods. Advanced control technologies are needed to limit microorganisms and increase the reliability of life support systems required for long-duration human missions. Silver ions and compounds are widely used as antimicrobial agents for medical applications and continue to be used as a residual biocide in some spacecraft water systems. The National Aeronautics and Space Administration (NASA) has identified silver fluoride for use in the potable water system on the next generation spacecraft. Due to ionic interactions between silver fluoride in solution and wetted metallic surfaces, ionic silver is rapidly depleted from solution and loses its antimicrobial efficacy over time. This report describes research to prolong the antimicrobial efficacy of ionic silver by maintaining its solubility. Three types of metal coupons (lnconel 718, Stainless Steel 316, and Titanium 6AI-4V) used in spacecraft potable water systems were exposed to either a continuous flow of water amended with 0.4 mg/L ionic silver fluoride or to a static, pre-treatment passivation in 50 mg/L ionic silver fluoride with or without a surface oxidation pre-treatment. Coupons were then challenged in a high-shear, CDC bioreactor (BioSurface Technologies) by exposure to six bacteria previously isolated from spacecraft potable water systems. Continuous exposure to 0.4 mg/L ionic silver over the course of 24 hours during the flow phase resulted in a >7-log reduction. The residual effect of a 24-hour passivation treatment in 50 mg/L of ionic silver resulted in a >3-log reduction, whereas a two-week treatment resulted in a >4-log reduction. Results indicate that 0.4 mg/L ionic silver is an effective biocide against many bacteria and that a prepassivation of metal surfaces with silver can provide additional microbial control.

  7. Air Sampling System Evaluation Template

    2000-05-09

    The ASSET1.0 software provides a template with which a user can evaluate an Air Sampling System against the latest version of ANSI N13.1 "Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stacks and Ducts of Nuclear Facilities". The software uses the ANSI N13.1 PIC levels to establish basic design criteria for the existing or proposed sampling system. The software looks at such criteria as PIC level, type of radionuclide emissions, physical state ofmore » the radionuclide, nozzle entrance effects, particulate transmission effects, system and component accuracy and precision evaluations, and basic system operations to provide a detailed look at the subsystems of a monitoring and sampling system/program. A GAP evaluation can then be completed which leads to identification of design and operational flaws in the proposed systems. Corrective measures can then be limited to the GAPs.« less

  8. Effects of plumbing systems on human exposure to disinfection byproducts in water: a case study.

    PubMed

    Chowdhury, Shakhawat

    2016-06-01

    Disinfection byproducts (DBPs) in water distribution systems (WDS) are monitored for regulatory compliance, while populations are exposed to DBPs in tap water that may be different due to stagnation of water in plumbing pipes (PP) and heating in hot water tanks (HWT). This study investigated the effects of water stagnation in PP and HWT on exposure and risk of DBPs to humans. Trihalomethanes (THMs) in PP and HWT were observed to be 1.1-2.4 and 1.6-3.0 times, respectively, to THMs in the WDS, while haloacetic acids (HAAs) were 0.9-1.8 and 1.2-1.9 times, respectively, to HAAs in the WDS. The chronic daily intakes of DBPs from PP and HWT were 0.6-1.8 and 0.5-2.3 times the intakes from WDS. The cancer risks from PP and HWT were 1.46 (0.40-4.3) and 1.68 (0.35-5.1) times the cancer risks from WDS. The findings may assist in regulating DBPs exposure concentrations. PMID:27280613

  9. Removal of disinfection by-products in raw water using a biological powder-activated carbon system.

    PubMed

    Lou, Jie C; Tseng, Wei B; Wu, Ming C; Han, Jia Y; Chen, Bi H

    2012-01-01

    This study investigates the removal efficiency of disinfection by-products (DBPs) in raw water at a water treatment plant using a biological powder-activated carbon system (BPACS). The presence of an excessive amount of DBPs has a large impact on the water quality of drinking water treated from the purification process. This study collected rapidly filtered water from an advanced water treatment plant for use in experiments on raw water. The removal efficiency of the trihalomethane formation potential (THMFP) and haloacetic acids formation potential (HAAFP) was studied under various hydraulic retention times and under organic DOC loadings. The results showed that the BPACS lowered the average concentration of dissolved organic carbon (DOC), UV(254) and the SUVA value (equivalent to UV(254)/DOC) in raw water. The system efficiently removed the THMFP and HAAFP during the treatment of the three primary organic carbon items. These results highlight the importance of the BPACS for efficiently treating disinfection by-products. These discoveries provide important information on biological degradation behaviors that can remove excessive amounts of disinfection by-products from drinking water.

  10. Efficacy of an Automated Multiple Emitter Whole-Room Ultraviolet-C Disinfection System Against Coronaviruses MHV and MERS-CoV.

    PubMed

    Bedell, Kurt; Buchaklian, Adam H; Perlman, Stanley

    2016-05-01

    Efficient and automated methods of disinfecting surfaces contaminated with the Middle Eastern respiratory syndrome coronavirus (MERS-CoV) may prevent the spread of the virus. Here we report the efficacy and use of an automated triple-emitter whole room UV-C disinfection system to inactivate mouse hepatitis virus, strain A59 (MHV-A59) and MERS-CoV viruses on surfaces with a >5 log10 reduction.

  11. Lighting the way to improved disinfection

    SciTech Connect

    Valenti, M.

    1997-07-01

    Ultraviolet light has a proven track record of killing bacteria and viruses found in municipal wastewater. In addition, environmental concerns over the use of chemical disinfectants, coupled with improvements in ultraviolet-lighting technology, have led to the development of UV systems that treat spent metalworking fluids in the industrialized world; disinfect drinking water in developing countries; and clean aquaculture water, ballast water, and hospital air everywhere. A large-scale pilot plant capable of treating less than 1 million gallons per day was built on-site by Los Angeles-based Montgomery Watson and CCCSD in 1992. It demonstrated that UV was just as effective as chlorination in killing bacteria and slightly more effective in destroying viruses found in the Martinez plant`s wastewater. It also showed the lamps would need to be cleaned of fouling every two to four weeks. The paper discusses this plant and the use of UV light in the above-mentioned water treatment processes.

  12. 40 CFR 141.543 - How is the disinfection benchmark calculated?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false How is the disinfection benchmark... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.543 How is the disinfection benchmark calculated? If your system is making a significant change to its disinfection practice, it...

  13. 40 CFR 141.543 - How is the disinfection benchmark calculated?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false How is the disinfection benchmark... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.543 How is the disinfection benchmark calculated? If your system is making a significant change to its disinfection practice, it...

  14. 40 CFR 141.543 - How is the disinfection benchmark calculated?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false How is the disinfection benchmark... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.543 How is the disinfection benchmark calculated? If your system is making a significant change to its disinfection practice, it...

  15. 40 CFR 141.543 - How is the disinfection benchmark calculated?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false How is the disinfection benchmark... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.543 How is the disinfection benchmark calculated? If your system is making a significant change to its disinfection practice, it...

  16. Control of dangerous substances in discharges and microbiological abatement: European framework and a case study of an ozone disinfection system.

    PubMed

    Ostoich, M; Serena, F; Falletti, L; Fantoni, A

    2013-01-01

    satisfied. Therefore, despite the high organic and industrial load of the considered plant and the need to find an alternative system for chlorine, as chlorine disinfection has been banned in the Veneto region since December 2012, ozone efficiency is not completely satisfactory and other systems such as peracetic or performic acids and UV systems must be considered. PMID:23508147

  17. Control of dangerous substances in discharges and microbiological abatement: European framework and a case study of an ozone disinfection system.

    PubMed

    Ostoich, M; Serena, F; Falletti, L; Fantoni, A

    2013-01-01

    satisfied. Therefore, despite the high organic and industrial load of the considered plant and the need to find an alternative system for chlorine, as chlorine disinfection has been banned in the Veneto region since December 2012, ozone efficiency is not completely satisfactory and other systems such as peracetic or performic acids and UV systems must be considered.

  18. Development of static system procedures to study aquatic biofilms and their responses to disinfection and invading species

    NASA Technical Reports Server (NTRS)

    Smithers, G. A.

    1992-01-01

    The microbial ecology facility in the Analytical and Physical Chemistry Branch at Marshall Space Flight Center is tasked with anticipation of potential microbial problems (and opportunities to exploit microorganisms) which may occur in partially closed systems such as space station/vehicles habitats and in water reclamation systems therein, with particular emphasis on the degradation of materials. Within this context, procedures for microbial biofilm research are being developed. Reported here is the development of static system procedures to study aquatic biofilms and their responses to disinfection and invading species. Preliminary investigations have been completed. As procedures are refined, it will be possible to focus more closely on the elucidation of biofilm phenomena.

  19. Disinfection Addition and Disinfection Changes: What It Means to the LCR

    EPA Science Inventory

    This slide presentation’s general points are: Many protective pipe scales are vey dependent on ORP, and hence, state of disinfection. Adding disinfection to anoxic systems will likely cause big chemistry changes in DS and corrosion. Changing disinfectants could cause major l...

  20. Field efficacy evaluation and post-treatment contamination risk assessment of an ultraviolet disinfection and safe storage system.

    PubMed

    Reygadas, Fermin; Gruber, Joshua S; Ray, Isha; Nelson, Kara L

    2015-11-15

    Inconsistent use of household water treatment and safe storage (HWTS) systems reduces their potential health benefits. Ultraviolet (UV) disinfection is more convenient than some existing HWTS systems, but it does not provide post-treatment residual disinfectant, which could leave drinking water vulnerable to recontamination. In this paper, using as-treated analyses, we report on the field efficacy of a UV disinfection system at improving household drinking water quality in rural Mexico. We further assess the risk of post-treatment contamination from the UV system, and develop a process-based model to better understand household risk factors for recontamination. This study was part of a larger cluster-randomized stepped wedge trial, and the results complement previously published population-level results of the intervention on diarrheal prevalence and water quality. Based on the presence of Escherichia coli (proportion of households with ≥ 1 E. coli/100 mL), we estimated a risk difference of -28.0% (95% confidence interval (CI): -33.9%, -22.1%) when comparing intervention to control households; -38.6% (CI: -48.9%, -28.2%) when comparing post- and pre-intervention results; and -37.1% (CI: -45.2%, -28.9%) when comparing UV disinfected water to alternatives within the household. We found substantial increases in post-treatment E. coli contamination when comparing samples from the UV system effluent (5.0%) to samples taken from the storage container (21.1%) and drinking glasses (26.0%). We found that improved household infrastructure, additional extractions from the storage container, additional time from when the storage container was filled, and increased experience of the UV system operator were associated with reductions in post-treatment contamination. Our results suggest that the UV system is efficacious at improving household water quality when used as intended. Promoting safe storage habits is essential for an effective UV system dissemination. The drinking

  1. Field efficacy evaluation and post-treatment contamination risk assessment of an ultraviolet disinfection and safe storage system.

    PubMed

    Reygadas, Fermin; Gruber, Joshua S; Ray, Isha; Nelson, Kara L

    2015-11-15

    Inconsistent use of household water treatment and safe storage (HWTS) systems reduces their potential health benefits. Ultraviolet (UV) disinfection is more convenient than some existing HWTS systems, but it does not provide post-treatment residual disinfectant, which could leave drinking water vulnerable to recontamination. In this paper, using as-treated analyses, we report on the field efficacy of a UV disinfection system at improving household drinking water quality in rural Mexico. We further assess the risk of post-treatment contamination from the UV system, and develop a process-based model to better understand household risk factors for recontamination. This study was part of a larger cluster-randomized stepped wedge trial, and the results complement previously published population-level results of the intervention on diarrheal prevalence and water quality. Based on the presence of Escherichia coli (proportion of households with ≥ 1 E. coli/100 mL), we estimated a risk difference of -28.0% (95% confidence interval (CI): -33.9%, -22.1%) when comparing intervention to control households; -38.6% (CI: -48.9%, -28.2%) when comparing post- and pre-intervention results; and -37.1% (CI: -45.2%, -28.9%) when comparing UV disinfected water to alternatives within the household. We found substantial increases in post-treatment E. coli contamination when comparing samples from the UV system effluent (5.0%) to samples taken from the storage container (21.1%) and drinking glasses (26.0%). We found that improved household infrastructure, additional extractions from the storage container, additional time from when the storage container was filled, and increased experience of the UV system operator were associated with reductions in post-treatment contamination. Our results suggest that the UV system is efficacious at improving household water quality when used as intended. Promoting safe storage habits is essential for an effective UV system dissemination. The drinking

  2. Zoned heating and air conditioning system

    SciTech Connect

    Beachboard, S.A.

    1987-06-16

    This patent describes a zoned heating and air conditioning system comprising: a central air handling system with an air heating means and an air cooling means and a blower connected to an air duct system; thermostats each have heating and cooling set points, respectively associated with and located in different zones of a building; dampers respectively associated with each building zone positioned in the air duct system. Each damper has an open position allowing air into the respective zone from the duct system and a closed position; relay means for connecting one thermostat to the air handling system upon a call for heating or cooling by one thermostat and disconnecting all other thermostats by connecting one thermostat's connections between the thermostat and air handling system. Only one thermostat is connected to the air handling system at a time and the relay means disconnects one thermostat from the air handling system after one thermostat is satisified; and damper actuating means for unlocking each damper in one building zone responsive actuated by a respective zone thermostat connected to the air handling system by the relay means. The damper actuates means including a damper solenoid for each damper located adjacent each damper and connected to a respective zone thermostat. It unlocks each damper in one building zone responsive to being actuated by the respective zone thermostat and unlocks the dampers in one building zone when one thermostat is actuated while preventing the dampers in another thermostat's building zone from unlocking.

  3. Compressed air energy storage system

    DOEpatents

    Ahrens, Frederick W.; Kartsounes, George T.

    1981-01-01

    An internal combustion reciprocating engine is operable as a compressor during slack demand periods utilizing excess power from a power grid to charge air into an air storage reservoir and as an expander during peak demand periods to feed power into the power grid utilizing air obtained from the air storage reservoir together with combustible fuel. Preferably the internal combustion reciprocating engine is operated at high pressure and a low pressure turbine and compressor are also employed for air compression and power generation.

  4. Compressed air energy storage system

    DOEpatents

    Ahrens, F.W.; Kartsounes, G.T.

    An internal combustion reciprocating engine is operable as a compressor during slack demand periods utilizing excess power from a power grid to charge air into an air storage reservoir and as an expander during peak demand periods to feed power into the power grid utilizing air obtained from the air storage reservoir together with combustion reciprocating engine is operated at high pressure and a low pressure turbine and compressor are also employed for air compression and power generation.

  5. Photoactivated disinfection (PAD) of dental root canal system – An ex-vivo study

    PubMed Central

    Mohan, Dennis; Maruthingal, Sunith; Indira, Rajamani; Divakar, Darshan Devang; Al Kheraif, Abdulaziz Abdullah; Ramakrishnaiah, Ravikumar; Durgesh, B.H.; Basavarajappa, Santhosh; John, Jacob

    2015-01-01

    Aim To investigate the efficacy of photo activated disinfection (PAD) in reducing colony-forming unit (CFU) counts of Enterococcus faecalis (E. faecalis) in infected dental root canals. The study compared the efficacy of PAD with conventional endodontic treatment (CET) and also a combination of CET along with PAD. Material and Methods 53 maxillary incisors were taken for the study. Teeth were divided into 3 groups, CET (Group I) (n = 11), PAD (Group II) (n = 21), and a combination of CET and PAD (Group III) which consisted of (n = 21) samples, Group II and Group III were further divided into 2 subgroups, Group IIa, IIb and Group IIIa, IIIb. Strains of E. faecalis were inoculated in all the root canals. CET group samples were treated by chemo-mechanical preparation (CMP) alone, PAD samples were treated with laser alone at 2 different exposure time (4 min and 2 min). In the combination treatment, samples were treated initially by CET and then by PAD for a time period of 4 min and 2 min. Contents of the root canal were aspirated, diluted and plated in Tryptone Soya Broth (TSB) and plates were incubated for 24 h to observe the bacterial regrowth. Results Showed PAD used along with CMP reduced the bacterial load of E. faecalis by 99.5% at 4 min and 98.89% at 2 min. Conclusion PAD may be an adjunctive procedure to kill residual bacteria in the dental root canal systems after standard endodontic root canal preparation. PMID:26858548

  6. Occurrence of regulated and non-regulated disinfection by-products in small drinking water systems.

    PubMed

    Guilherme, Stéphanie; Rodriguez, Manuel J

    2014-12-01

    The occurrence of regulated and non-regulated disinfection by-products (DBPs) was investigated in the drinking water of small systems in two provinces in Canada, Newfoundland and Labrador (NL) and Quebec (QC), through an intensive sampling program. Sixteen DBPs were studied: four trihalomethanes (THMs), five haloacetic acids (HAAs), four haloacetonitriles (HANs), one halonitromethane, chloropikrin (CPK) and two haloketones (HKs). Average measured concentrations of these compounds were much higher than those reported in the literature for medium and large systems. The measured average value for THMs was 75 μg L(-1) (Stdv=69μgL(-1)); HAAs, 77 μg L(-1) (Stdv=75 μg L(-1)); HANs, 2.5 μg L(-1) (Stdv=1.8 μg L(-1)); CPK, 0.4 μg L(-1) (Stdv=0.3 μg L(-1)) and HKs, 6.0 μg L(-1) (Stdv=4.5 μg L(-1)). The gap (some 10 times difference) between the average levels of regulated DBPs (THMs, HAAs) and non-regulated DBPs (HANs, CPK and HKs) is comparable to that observed in large systems where the occurrence of the same compounds has been reported. Generally, investigated DBPs followed a comparable seasonal evolution during the year: they decreased between the fall and winter and then increased to eventually reach a maximum in late summer. This trend was less observable in NL than in QC. However, observed seasonal fluctuations of DBPs were less considerable than those observed in medium and large systems located in similar temperate environments reported in the literature. Spatial variations from the plant to the extremities were high and comparable to those observed in large systems, which is surprising, considering the smaller size of distribution networks supplying small communities. Generally speaking, the results support the premise that problems associated with implementing treatment that removes DBP precursors in water submitted to chlorination can increase population exposure to these contaminants in small systems.

  7. Strategy Guideline. Compact Air Distribution Systems

    SciTech Connect

    Burdick, Arlan

    2013-06-01

    This guideline discusses the benefits and challenges of using a compact air distribution system to handle the reduced loads and reduced air volume needed to condition the space within an energy efficient home. The decision criteria for a compact air distribution system must be determined early in the whole-house design process, considering both supply and return air design. However, careful installation of a compact air distribution system can result in lower material costs from smaller equipment, shorter duct runs, and fewer outlets; increased installation efficiencies, including ease of fitting the system into conditioned space; lower loads on a better balanced HVAC system, and overall improved energy efficiency of the home.

  8. Air Force Training for Instructional Systems Development.

    ERIC Educational Resources Information Center

    Calkins, Ronald R.

    Detailed information is provided about the Air Force Instructional System Development (ISD) Model to supplement the 1979 AECT presentation made in New Orleans. Information of interest to instructional systems designers includes (1) a short overview of the Air Force ISD model, (2) an extended example which demonstrates the Air Training Command…

  9. Strategy Guideline: Compact Air Distribution Systems

    SciTech Connect

    Burdick, A.

    2013-06-01

    This Strategy Guideline discusses the benefits and challenges of using a compact air distribution system to handle the reduced loads and reduced air volume needed to condition the space within an energy efficient home. Traditional systems sized by 'rule of thumb' (i.e., 1 ton of cooling per 400 ft2 of floor space) that 'wash' the exterior walls with conditioned air from floor registers cannot provide appropriate air mixing and moisture removal in low-load homes. A compact air distribution system locates the HVAC equipment centrally with shorter ducts run to interior walls, and ceiling supply outlets throw the air toward the exterior walls along the ceiling plane; alternatively, high sidewall supply outlets throw the air toward the exterior walls. Potential drawbacks include resistance from installing contractors or code officials who are unfamiliar with compact air distribution systems, as well as a lack of availability of low-cost high sidewall or ceiling supply outlets to meet the low air volumes with good throw characteristics. The decision criteria for a compact air distribution system must be determined early in the whole-house design process, considering both supply and return air design. However, careful installation of a compact air distribution system can result in lower material costs from smaller equipment, shorter duct runs, and fewer outlets; increased installation efficiencies, including ease of fitting the system into conditioned space; lower loads on a better balanced HVAC system, and overall improved energy efficiency of the home.

  10. Ultraviolet disinfection of potable water

    SciTech Connect

    Wolfe, R.L. )

    1990-06-01

    Because of upcoming surface and groundwater regulations regarding the control of microbiological and chemical contaminants, there is a need to evaluate the feasibility and effectiveness of ultraviolet (UV) radiation for primary disinfection of potable water supplies. Data is presented on microbicidal wavelengths of UV and distribution of energy output for low and medium-pressure arc lamps. Both systems were found to perform equally well for inactivating microorganisms, but each had distinct advantages in different applications. Approximate dosages for 90% inactivation of selected microorganisms by UV is presented in a table. Cost analysis for disinfection is presented in two tables as well as the advantages and disadvantages of UV disinfection. 38 refs.

  11. Industrial Compressed Air System Energy Efficiency Guidebook.

    SciTech Connect

    United States. Bonneville Power Administration.

    1993-12-01

    Energy efficient design, operation and maintenance of compressed air systems in industrial plants can provide substantial reductions in electric power and other operational costs. This guidebook will help identify cost effective, energy efficiency opportunities in compressed air system design, re-design, operation and maintenance. The guidebook provides: (1) a broad overview of industrial compressed air systems, (2) methods for estimating compressed air consumption and projected air savings, (3) a description of applicable, generic energy conservation measures, and, (4) a review of some compressed air system demonstration projects that have taken place over the last two years. The primary audience for this guidebook includes plant maintenance supervisors, plant engineers, plant managers and others interested in energy management of industrial compressed air systems.

  12. [Air quality control systems: heating, ventilating, and air conditioning (HVAC)].

    PubMed

    Bellucci Sessa, R; Riccio, G

    2004-01-01

    After a brief illustration of the principal layout schemes of Heating, Ventilating, and Air Conditioning (HVAC), the first part of this paper summarizes the standards, both voluntary and compulsory, regulating HVAC facilities design and installation with regard to the question of Indoor Air Quality (IAQ). The paper then examines the problem of ventilation systems maintenance and the essential hygienistic requirements in whose absence HVAC facilities may become a risk factor for people working or living in the building. Lastly, the paper deals with HVAC design strategies and methods, which aim not only to satisfy comfort and air quality requirements, but also to ensure easy and effective maintenance procedures.

  13. Short-term spatial and temporal variability of disinfection by-product occurrence in small drinking water systems.

    PubMed

    Guilherme, Stéphanie; Rodriguez, Manuel J

    2015-06-15

    Disinfection by-products (DBPs) constitute a large family of compounds. Trihalomethanes and haloacetic acids are regulated in various countries, but most DBPs are not. Monitoring DBPs can be delicate, especially for small systems, because various factors influence their formation and speciation. Short-term variations of DBPs can be important and particularly difficult for small systems to handle because they require robust treatment and operation processes. According to our knowledge, for the first time, our study covers the short-term variability of regulated and non-regulated DBP occurrence in small systems in the summer. An intensive sampling program was carried out in six small systems in Canada. Systems in the provinces of Newfoundland and Labrador and Quebec were sampled daily at the water treatment plant and at six different locations along the distribution system. Five DBP families were studied: trihalomethanes, haloacetic acids, haloacetonitriles, halonitromethanes and haloketones. Results show that there were considerable variations in DBP levels from week to week during the month of study and even from day to day within the week. On a daily basis, DBP levels can fluctuate by 22% to 96%. Likewise, the large number of sampling locations served to observe DBP variations along the distribution system. Observations revealed some degradation and decomposition of non-regulated DBPs never before studied in small systems that are associated with the difficulty these systems experience in maintaining adequate levels of residual disinfectant. Finally, this study reveals that the short term temporal variability of DBPs is also influenced by spatial location along the distribution system. In the short term, DBP levels can fluctuate by 23% at the beginning of the system, compared to 40% at the end. Thus, spatial and temporal variations of DBPs in the short term may make it difficult to select representative locations and periods for DBP monitoring purposes in small

  14. Methyl bromide as a building disinfectant: interaction with indoor materials and resulting byproduct formation.

    PubMed

    Corsi, Richard L; Walker, Matthew B; Liljestrand, Howard M; Hubbard, Heidi F; Poppendieck, Dustin G

    2007-05-01

    Several buildings were contaminated with Bacillus anthracis in the fall of 2001. These events required consideration of how to disinfect large indoor spaces for continued worker occupation. The interactions of gaseous disinfectants with indoor materials may inhibit the disinfection process, cause persistence of the disinfectant, and lead to possible byproduct formation and persistence. Methyl bromide (CH3Br) is a candidate for disinfection/deactivation of biological agents in buildings. In this study, 24 indoor materials were exposed to CH3Br for 16 hr at concentrations ranging from 100 to 2500 ppm in 48-L electropolished stainless steel chambers. CH3Br concentrations were measured during and after disinfection. Its interactions with materials were observed to be small, with nearly complete and rapid desorption. Between 3% and 8% of CH3Br adsorbed to four materials (office partition, ceiling tile, particle-board, and gypsum wallboard with satin paint), and the degree of adsorption decreased with increasing relative humidity. The percentage of adsorption to all other materials was <2%. This result suggests that when designing disinfection events with CH3Br, loss to indoor materials can be neglected in terms of disinfectant dose calculations. Possible reaction products were identified and/or quantified before and after exposure to CH3Br. Several monomethylated and dimethylated aliphatic compounds were observed in chamber air at low concentrations after the exposures of six materials to CH3Br. Concentration increases also occurred for chemicals that were observed to naturally off-gas from materials before exposure to CH3Br, suggesting that CH3Br may play a role in enhancing the natural off-gassing of chemicals, for example, by competitive displacement of compounds that already existed in the materials. The results described in this paper should facilitate the design of building disinfection systems involving CH3Br.

  15. Characterization of biofilm and corrosion of cast iron pipes in drinking water distribution system with UV/Cl2 disinfection.

    PubMed

    Zhu, Ying; Wang, Haibo; Li, Xiaoxiao; Hu, Chun; Yang, Min; Qu, Jiuhui

    2014-09-01

    The effect of UV/Cl2 disinfection on the biofilm and corrosion of cast iron pipes in drinking water distribution system were studied using annular reactors (ARs). Passivation occurred more rapidly in the AR with UV/Cl2 than in the one with Cl2 alone, decreasing iron release for higher corrosivity of water. Based on functional gene, pyrosequencing assays and principal component analysis, UV disinfection not only reduced the required initial chlorine dose, but also enhanced denitrifying functional bacteria advantage in the biofilm of corrosion scales. The nitrate-reducing bacteria (NRB) Dechloromonas exhibited the greatest corrosion inhibition by inducing the redox cycling of iron to enhance the precipitation of iron oxides and formation of Fe3O4 in the AR with UV/Cl2, while the rhizobia Bradyrhizobium and Rhizobium, and the NRB Sphingomonas, Brucella producing siderophores had weaker corrosion-inhibition effect by capturing iron in the AR with Cl2. These results indicated that the microbial redox cycling of iron was possibly responsible for higher corrosion inhibition and lower effect of water Larson-Skold Index (LI) changes on corrosion. This finding could be applied toward the control of water quality in drinking water distribution systems.

  16. 40 CFR 141.72 - Disinfection.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... for Giardia lamblia cysts and viruses. If a system uses a disinfectant other than chlorine, the system...) The residual disinfectant concentration in the distribution system, measured as total chlorine, combined chlorine, or chlorine dioxide, as specified in § 141.74 (a)(2) and (b)(6), cannot be...

  17. SpaceX Dragon Air Circulation System

    NASA Technical Reports Server (NTRS)

    Hernandez, Brenda; Piatrovich, Siarhei; Prina, Mauro

    2011-01-01

    The Dragon capsule is a reusable vehicle being developed by Space Exploration Technologies (SpaceX) that will provide commercial cargo transportation to the International Space Station (ISS). Dragon is designed to be a habitable module while it is berthed to ISS. As such, the Dragon Environmental Control System (ECS) consists of pressure control and pressure equalization, air sampling, fire detection, illumination, and an air circulation system. The air circulation system prevents pockets of stagnant air in Dragon that can be hazardous to the ISS crew. In addition, through the inter-module duct, the air circulation system provides fresh air from ISS into Dragon. To utilize the maximum volume of Dragon for cargo packaging, the Dragon ECS air circulation system is designed around cargo rack optimization. At the same time, the air circulation system is designed to meet the National Aeronautics Space Administration (NASA) inter-module and intra-module ventilation requirements and acoustic requirements. A flight like configuration of the Dragon capsule including the air circulation system was recently assembled for testing to assess the design for inter-module and intra-module ventilation and acoustics. The testing included the Dragon capsule, and flight configuration in the pressure section with cargo racks, lockers, all of the air circulation components, and acoustic treatment. The air circulation test was also used to verify the Computational Fluid Dynamics (CFD) model of the Dragon capsule. The CFD model included the same Dragon internal geometry that was assembled for the test. This paper will describe the Dragon air circulation system design which has been verified by testing the system and with CFD analysis.

  18. Sorting through the Wealth of Options: Comparative Evaluation of Two Ultraviolet Disinfection Systems

    PubMed Central

    Nerandzic, Michelle M.; Fisher, Christopher W.; Donskey, Curtis J.

    2014-01-01

    Background Environmental surfaces play an important role in the transmission of healthcare-associated pathogens. Because environmental cleaning is often suboptimal, there is a growing demand for safe, rapid, and automated disinfection technologies, which has lead to a wealth of novel disinfection options available on the market. Specifically, automated ultraviolet-C (UV-C) devices have grown in number due to the documented efficacy of UV-C for reducing healthcare-acquired pathogens in hospital rooms. Here, we assessed and compared the impact of pathogen concentration, organic load, distance, and radiant dose on the killing efficacy of two analogous UV-C devices. Principal Findings The devices performed equivalently for each impact factor assessed. Irradiation delivered for 41 minutes at 4 feet from the devices consistently reduced C. difficile spores by ∼ 3 log10CFU/cm2, MRSA by>4 log10CFU/cm2, and VRE by >5 log10CFU/cm2. Pathogen concentration did not significantly impact the killing efficacy of the devices. However, both a light and heavy organic load had a significant negative impacted on the killing efficacy of the devices. Additionally, increasing the distance to 10 feet from the devices reduced the killing efficacy to ≤3 log10CFU/cm2 for MRSA and VRE and <2 log10CFU/cm2 for C.difficile spores. Delivery of reduced timed doses of irradiation particularly impacted the ability of the devices to kill C. difficile spores. MRSA and VRE were reduced by >3 log10CFU/cm2 after only 10 minutes of irradiation, while C. difficile spores required 40 minutes of irradiation to achieve a similar reduction. Conclusions The UV-C devices were equally effective for killing C. difficile spores, MRSA, and VRE. While neither device would be recommended as a stand-alone disinfection procedure, either device would be a useful adjunctive measure to routine cleaning in healthcare facilities. PMID:25247783

  19. Air ion exposure system for plants

    NASA Technical Reports Server (NTRS)

    Morrow, R. C.; Tibbitts, T. W.

    1987-01-01

    A system was developed for subjecting plants to elevated air ion levels. This system consisted of a rectangular Plexiglas chamber lined with a Faraday cage. Air ions were generated by corona discharge from frayed stainless steel fibers placed at one end of the chamber. This source was capable of producing varying levels of either positive or negative air ions. During plant exposures, environmental conditions were controlled by operating the unit in a growth chamber.

  20. New formaldehyde base disinfectants.

    NASA Technical Reports Server (NTRS)

    Trujillo, R.; Lindell, K. F.

    1973-01-01

    Preparations of formaldehyde in various organic liquids - ethylene glycol, glycerol, and propylene glycol - serve as effective disinfectants towards microbial vegetative cells and spores. This disinfection is a temperature-dependent process and is manifest when these formaldehyde base disinfectants are dissolved in water. The irritating vapors associated with formaldehyde disinfection are not present in either of these new formaldehyde base disinfectants or in aqueous solutions of them.

  1. A New Approach to Performance Analysis of Disinfection Using Grey System Theory

    NASA Astrophysics Data System (ADS)

    Li, Rongguang; He, Wenjie; Han, Hongda; Wu, Wei; Meng, Xianxian

    It is important to reduce sanitary risks related to the presence of pathogens and disinfection can be achieved via chlorination. In this paper, GM (1, 1) model was employed to predict the rate of inactivation with free chlorine for Enterococcus faecalis. The result indicated that GM only required a small amount of data can predict well. The mean absolute percentage errors (MAPEs) using GM(1,1) model lay between 0.04%-9.75%. Research results show that this GM(1,1)model can provide valuable information for public health.

  2. Rooftop Unitary Air Conditioner with Integral Dedicated Outdoor Air System

    SciTech Connect

    Tiax Llc

    2006-02-28

    Energy use of rooftop and other unitary air-conditioners in commercial applications accounts for about 1 quad (10{sup 15} Btu) of primary energy use annually in the U.S. [Reference 7]. The realization that this cooling equipment accounts for the majority of commercial building cooled floorspace and the majority also of commercial building energy use has spurred development of improved-efficiency equipment as well as development of stricter standards addressing efficiency levels. Another key market driver affecting design of rooftop air-conditioning equipment has been concern regarding comfort and the control of humidity. Trends for increases in outdoor air ventilation rates in certain applications, and the increasing concern about indoor air quality problems associated with humidity levels and moisture in buildings points to a need for improved dehumidification capability in air-conditioning equipment of all types. In many cases addressing this issue exacerbates energy efficiency, and vice versa. The integrated dedicated outdoor air system configuration developed in this project addresses both energy and comfort/humidity issues.

  3. Solar Hot-Air System --Memphis, Tennessee

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Solar collectors using air as collection medium provide space heating for four-building office complex in Memphis. 98 page report furnishes details on installation, including: description of system; system startup and acceptance-test results; technical data on collector; installation manuals for collectors, air handler and heat-storage unit.

  4. Effect of temperature and disinfection strategies on ammonia-oxidizing bacteria in a bench-scale drinking water distribution system.

    PubMed

    Pintar, Katarina D M; Slawson, Robin M

    2003-04-01

    The establishment of ammonia-oxidizing bacteria (AOB), a group of autotrophic microorganisms responsible for nitrification in chloraminated distribution systems, was studied in a bench-scale distribution system. The potential significance of temperature and disinfectant residual associated with chloramination in full-scale drinking water distribution systems was assessed. Biofilm development was primarily monitored using AOB abundance and nitrite concentrations. The bench-scale system was initially operated under typical North American summer (22 degrees C) and fall (12 degrees C) temperatures, representing optimal and less optimal growth ranges for these microorganisms. Additional experimentation investigated AOB establishment at a suboptimal winter distribution system temperature of 6 degrees C. The effect of chloramine residual on AOB establishment was studied at higher (0.2-0.6mg/L) and lower (0.05-0.1mg/L) ranges, using a 3:1 (w/w) chlorine:ammonia dosing ratio. Conditions were selected to represent those typically found in a North American distribution system, in areas of low flow and longer retention times, respectively. Finally, the effect of a free chlorine residual on an established nitrifying biofilm was briefly examined. Results clearly indicate that AOB development occurs at all examined temperatures, as well as at selected monochloramine residuals. The maintenance of a disinfectant residual was difficult at times, but was more inhibitory to the nitrifying biofilm than the lower temperature. It can be concluded from the data that nitrification may not be adequately inhibited during the winter months, which may result in more advanced stages of nitrification the following season. Free chlorination can be effective in controlling AOB activity in the short term, but may not prevent reestablishment of a nitrifying biofilm upon return to chloramination.

  5. Decontamination formulations for disinfection and sterilization

    DOEpatents

    Tucker, Mark D.; Engler, Daniel E.

    2007-09-18

    Aqueous decontamination formulations that neutralize biological pathogens for disinfection and sterilization applications. Examples of suitable applications include disinfection of food processing equipment, disinfection of areas containing livestock, mold remediation, sterilization of medical instruments and direct disinfection of food surfaces, such as beef carcasses. The formulations include at least one reactive compound, bleaching activator, inorganic base, and water. The formulations can be packaged as a two-part kit system, and can have a pH value in the range of 7-8.

  6. Optical air data systems and methods

    NASA Technical Reports Server (NTRS)

    Caldwell, Loren M. (Inventor); Tang, Shoou-yu (Inventor); Acott, Phillip E. (Inventor); Spaeth, Lisa G. (Inventor); O'Brien, Martin (Inventor)

    2011-01-01

    Systems and methods for sensing air includes at least one, and in some embodiments three, transceivers for projecting the laser energy as laser radiation to the air. The transceivers are scanned or aligned along several different axes. Each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines air temperatures, wind speeds, and wind directions based on the scattered laser radiation. Applications of the system to wind power site evaluation, wind turbine control, traffic safety, general meteorological monitoring and airport safety are presented.

  7. Fluid-bed air-supply system

    DOEpatents

    Atabay, Keramettin

    1979-01-01

    The air-supply system for a fluidized-bed furnace includes two air conduits for the same combustion zone. The conduits feed separate sets of holes in a distributor plate through which fluidizing air flows to reach the bed. During normal operation, only one conduit and set of holes is used, but the second conduit and set of holes is employed during start-up.

  8. Anticipating challenges with in-building disinfection for control of opportunistic pathogens.

    PubMed

    Rhoads, William J; Pruden, Amy; Edwards, Marc A

    2014-06-01

    A new American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standard for control of Legionella (ASHRAE Standard 188, 2013) emphasizes use of in-building disinfection techniques to reduce the exposure of at-risk consumers to opportunistic pathogens in premise plumbing (OPPPs). This standard and other recommendations for OPPP control have implications for scaling in and corrosion of plumbing systems, which can sometimes adversely affect the efficacy of the disinfection method and physical integrity of the plumbing system, prompting this proactive critical review of challenges associated with implementation of Standard 188. PMID:25109200

  9. Disinfecting activities of non-peroxide soft contact lens cold disinfection solutions.

    PubMed

    Shih, K L; Raad, M K; Hu, J C; Gresh, W J; Jiries, S I; Caldwell, L J; Bergamini, M V

    1991-07-01

    The antimicrobial activities of three non-peroxide soft contact lens chemical disinfection systems--ReNu Multi-Purpose Solution (0.00005% polyaminopropyl biguanide), Opti-Soft Disinfecting Solution (0.001% polyquaternium-1), and Opti-Free Rinsing, Disinfecting & Storage Solution (0.001% polyquaternium-1)--were compared to Soft Mate Disinfecting Solution (0.005% chlorhexidine digluconate). Each product was separately inoculated with each of five microorganisms at approximately 10(6) microorganisms per mL. All of the solutions demonstrated excellent disinfecting activity against Pseudomonas aeruginosa and Staphylococcus epidermidis, with complete disinfection occurring within 4 hours. Only Soft Mate disinfected Serratia marcescens within 4 hours. ReNu reduced the microorganisms to 10-100 cells/mL and Opti-Soft and Opti-Free reduced the number to 10(2)-10(3) cells/mL. For the fungal species, Soft Mate showed excellent activity against Candida albicans (disinfection in 4 hours) and reduced Aspergillus fumigatus to 10(3) spores/mL in 4 hours. After 4 hours ReNu, Opti-Soft, and Opti-Free had reduced C. albicans only slightly, to 10(5) cells/mL and displayed virtually no disinfecting activity against A. fumigatus. For these newer chemical disinfection systems, diligent cleaning and rinsing of the soft contact lenses are the most important steps in the patient care regimen.

  10. Review of water disinfection techniques

    NASA Technical Reports Server (NTRS)

    Colombo, Gerald V.; Sauer, Richard L.

    1987-01-01

    Throughout the history of manned space flight the supply of potable water to the astronauts has presented unique problems. Of particular concern has been the microbiological quality of the potable water. This has required the development of both preflight water system servicing procedures to disinfect the systems and inflight disinfectant addition and monitoring devices to ensure continuing microbiological control. The disinfectants successfully used to date have been aqueous chlorine or iodine. Because of special system limitations the use of iodine has been the most successful for inflight use and promises to be the agent most likely to be used in the future. Future spacecraft potable, hygiene, and experiment water systems will utilize recycled water. This will present special problems for water quality control. NASA is currently conducting research and development to solve these problems.

  11. Environmental contamination and airborne microbial counts: a role for hydroxyl radical disinfection units?

    PubMed

    Wong, V; Staniforth, K; Boswell, T C

    2011-07-01

    Environmental contamination is thought to play a role in the spread of infection in hospitals and there has been increased interest in novel air disinfection systems in preventing infection. In this study the efficacy of a hydroxyl radical air disinfection system (Inov8 unit) in reducing the number of airborne bacteria was assessed in a clinical setting. Environmental contamination was assessed using settle plates and air samples in three settings: (1) non-clinical room; (2) non-clinical room with defined activity; and (3) single intensive care unit cubicle. A comparison of air counts and environmental contamination rates was made with the Inov8 units on and off. The Inov8 unit produced an overall reduction in both air sample and settle plate counts in each setting (P<0.001, Wilcoxon signed-rank test). There was a mean reduction in air sample counts of 26%, 39% and 55% for settings 1, 2 and 3 respectively. The corresponding reductions in settle plate counts were 35%, 62% and 54%. These results suggest that this type of novel air disinfection may have a role in improving air quality and reducing environmental contamination within clinical isolation rooms. Further work is required to assess the effect on specific pathogens, and to establish whether this will reduce the risks of patients and/or healthcare workers acquiring such pathogens from the environment.

  12. Air-water flow in subsurface systems

    NASA Astrophysics Data System (ADS)

    Hansen, A.; Mishra, P.

    2013-12-01

    Groundwater traces its roots to tackle challenges of safe and reliable drinking water and food production. When the groundwater level rises, air pressure in the unsaturated Vadose zone increases, forcing air to escape from the ground surface. Abnormally high and low subsurface air pressure can be generated when the groundwater system, rainfall, and sea level fluctuation are favorably combined [Jiao and Li, 2004]. Through this process, contamination in the form of volatile gases may diffuse from the ground surface into residential areas, or possibly move into groundwater from industrial waste sites. It is therefore crucial to understand the combined effects of air-water flow in groundwater system. Here we investigate theoretically and experimentally the effects of air and water flow in groundwater system.

  13. Evaluation of an Innovative Approach to Validation of Ultraviolet (UV) Reactors for Disinfection in Drinking Water Systems

    EPA Science Inventory

    UV disinfection is an effective process for inactivating many microbial pathogens found in source waters with the potential as stand-alone treatment or in combination with other disinfectants. For surface and groundwater sourced drinking water applications, the U.S. Environmental...

  14. Systemic air embolization from penetrating lung injury.

    PubMed

    Meier, G H; Wood, W J; Symbas, P N

    1979-02-01

    This study evaluates the role of increased intratracheal pressure in developing systemic air embolization. Twenty healthy mongrel dogs were monitored for air embolization, both by means of an extracorporeal arteriovenous shunt constructed from transparent plastic tubing for visualization of air emboli and by means of a Doppler flow probe implanted at the root of the aorta. Systemic arterial, left atrial, intratracheal, and intrapleural pressures were recorded. In 10 of the dogs, a penetrating wound of the lung 1 cm wide by 4 cm deep was produced; in 5 the chest was left open and in 5 the chest was closed. The remaining 10 dogs served as controls (with no wound of the lung); in 5 the chest was left open and in the other 5 the chest was closed. No air embolization occurred in any animals at intratracheal pressures less than 65 mm Hg. However, systemic air embolization occurred in every dog in all groups upon hyperinflation of the lung above 65 mm Hg. The control groups differed from the groups with penetrating wound only in the quantity of embolized air. This study suggests that hyperinflation of the lung to an intratracheal pressure above 65 mm Hg results in systemic air embolization and that the presence of a penetrating wound of the lung at such intratracheal pressure predisposes to a greater quantity of air embolization.

  15. AEROMETRIC INFORMATION RETRIEVAL SYSTEM (AIRS) - GRAPHICS

    EPA Science Inventory

    Aerometric Information Retrieval System (AIRS) is a computer-based repository of information about airborne pollution in the United States and various World Health Organization (WHO) member countries. AIRS is administered by the U.S. Environmental Protection Agency, and runs on t...

  16. Solar-powered hot-air system

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Solar-powered air heater supplies part or all of space heating requirements of residential or commercial buildings and is interfaced with air to water heat exchanger to heat domestic hot water. System has potential application in drying agricultural products such as cotton, lumber, corn, grains, and peanuts.

  17. Air Systems Provide Life Support to Miners

    NASA Technical Reports Server (NTRS)

    2014-01-01

    Through a Space Act Agreement with Johnson Space Center, Paragon Space Development Corporation, of Tucson, Arizona, developed the Commercial Crew Transport-Air Revitalization System, designed to provide clean air for crewmembers on short-duration space flights. The technology is now being used to help save miners' lives in the event of an underground disaster.

  18. Disinfection byproducts in swimming pool: occurrences, implications and future needs.

    PubMed

    Chowdhury, Shakhawat; Alhooshani, Khalid; Karanfil, Tanju

    2014-04-15

    Disinfection of swimming pool water is essential to deactivate pathogenic microorganisms. Many swimming pools apply chlorine or bromine based disinfectants to prevent microbial growth. The chlorinated swimming pool water contains higher chlorine residual and is maintained at a higher temperature than a typical drinking water distribution system. It constitutes environments with high levels of disinfection by-products (DBPs) in water and air as a consequence of continuous disinfection and constant organic loading from the bathers. Exposure to those DBPs is inevitable for any bather or trainer, while such exposures can have elevated risks to human health. To date, over 70 peer-reviewed publications have reported various aspects of swimming pool, including types and quantities of DBPs, organic loads from bathers, factors affecting DBPs formation in swimming pool, human exposure and their potential risks. This paper aims to review the state of research on swimming pool including with the focus of DBPs in swimming pools, understand their types and variability, possible health effects and analyze the factors responsible for the formation of various DBPs in a swimming pool. The study identifies the current challenges and future research needs to minimize DBPs formation in a swimming pool and their consequent negative effects to bathers and trainers.

  19. 40 CFR 141.540 - Who has to develop a disinfection benchmark?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... benchmark? 141.540 Section 141.540 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.540 Who has to develop a disinfection benchmark? If you are a subpart H system required to develop a disinfection profile under §§...

  20. 40 CFR 141.540 - Who has to develop a disinfection benchmark?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... benchmark? 141.540 Section 141.540 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.540 Who has to develop a disinfection benchmark? If you are a subpart H system required to develop a disinfection profile under §§...

  1. 40 CFR 141.540 - Who has to develop a disinfection benchmark?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... benchmark? 141.540 Section 141.540 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.540 Who has to develop a disinfection benchmark? If you are a subpart H system required to develop a disinfection profile under §§...

  2. 40 CFR 141.540 - Who has to develop a disinfection benchmark?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... benchmark? 141.540 Section 141.540 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Disinfection-Systems Serving Fewer Than 10,000 People Disinfection Benchmark § 141.540 Who has to develop a disinfection benchmark? If you are a subpart H system required to develop a disinfection profile under §§...

  3. 40 CFR 141.72 - Disinfection.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Disinfection. 141.72 Section 141.72 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL... for Giardia lamblia cysts and viruses. If a system uses a disinfectant other than chlorine, the...

  4. 40 CFR 141.72 - Disinfection.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Disinfection. 141.72 Section 141.72 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL... for Giardia lamblia cysts and viruses. If a system uses a disinfectant other than chlorine, the...

  5. Effects of ozone, ultraviolet and peracetic acid disinfection of a primary-treated municipal effluent on the immune system of rainbow trout (Oncorhynchus mykiss).

    PubMed

    Hébert, N; Gagné, F; Cejka, P; Bouchard, B; Hausler, R; Cyr, D G; Blaise, C; Fournier, M

    2008-08-01

    Municipal sewage effluents are complex mixtures that are known to compromise the health condition of aquatic organisms. The aim of this study was to evaluate the impacts of various wastewater disinfection processes on the immune system of juvenile rainbow trout (Oncorhynchus mykiss). The trout were exposed to a primary-treated effluent for 28 days before and after one of each of the following treatments: ultraviolet (UV) radiation, ozonation and peracetic acid. Immune function was characterized in leucocytes from the anterior head kidney by the following three parameters: phagocytosis activity, natural cytotoxic cells (NCC) function and lymphocyte (B and T) proliferation assays. The results show that the fish mass to length ratio was significantly decreased for the primary-treated and all three disinfection processes. Exposure to the primary-treated effluent led to a significant increase in macrophage-related phagocytosis; the addition of a disinfection step was effective in removing this effect. Both unstimulated and mitogen-stimulated T lymphocyte proliferation in fish decreased dramatically in fish exposed to the ozonated effluent compared to fish exposed to either the primary-treated effluent or to aquarium water. Stimulation of T lymphocytes proliferation was observed with the peracetic acid treatment group. In conclusion, the disinfection strategy used can modify the immune system in fish at the level of T lymphocyte proliferation but was effective to remove the effects on phagocytosis activity.

  6. The effects of air leaks on solar air heating systems

    NASA Technical Reports Server (NTRS)

    Elkin, R.; Cash, M.

    1979-01-01

    This paper presents the results of an investigation to determine the effects of leakages in collector and duct work on the system performance of a typical single-family residence solar air heating system. Positive (leakage out) and negative (leakage in) pressure systems were examined. Collector and duct leakage rates were varied from 10 to 30 percent of the system flow rate. Within the range of leakage rates investigated, solar contribution to heated space and domestic hot water loads was found to be reduced up to 30 percent from the no-leak system contribution with duct leakage equally divided between supply and return duct; with supply duct leakage greater than return leakage a reduction of up to 35 percent was noted. The negative pressure system exhibited a reduction in solar contribution somewhat larger than the positive pressure system for the same leakage rates.

  7. Effect of Disinfectants on Glucose Monitors

    PubMed Central

    Mahoney, John J; Lim, Christine G

    2012-01-01

    Background Monitoring blood glucose levels is an integral part of routine diabetes management. To minimize the risk of transmission of bloodborne pathogens during monitoring, the Centers for Disease Control and Prevention (CDC) recommends that glucose meters be disinfected after each use whenever they are used to test multiple patients. The objective of this study is to assess the compatibility of some common disinfectants with certain blood glucose meter systems. Methods We tested six disinfectants for adverse impact on meter performance or the exterior meter surfaces. The disinfectants tested were 0.525% sodium hypochlorite, 20% 2-propanol and 10% ethanol, 17.2% isopropanol, 55% isopropanol, 70% isopropanol, and hydrogen peroxide. To assess meter performance, we tested OneTouch® Ultra® blood glucose monitoring systems with control solution before and after application of either water or disinfectant. To assess the effect on exterior meter surfaces, we performed a soaking test to simulate long-term exposure to disinfectant. Results Paired t-test results showed that the control solution data associated with disinfectant and with water application were not significantly different for each meter type. However, most of the meter types were adversely affected by hydrogen peroxide and/or by the higher concentrations of alcohol-based disinfectants. Conclusions Although none of the six disinfectants affected meter performance, hydrogen peroxide and isopropanol >20% adversely affected the exterior surfaces of the tested meters. When complying with CDC instructions for meter disinfection, users should use caution and choose disinfectants that have been validated by the meter manufacturer. PMID:22401326

  8. [Computer modeling of electrodynamic processes in SHF-based water disinfection and heating system as part of the spacecrew life support system].

    PubMed

    Klimarev, S I; Zaĭtsev, K A

    2012-01-01

    To optimize the design of SHF-based potable water disinfection and heating subsystem within the life support system (LSS), computer modeling of the super-high frequency electromagnetic field in SHF-based waveguide-coaxial and coaxial running water heaters was performed Software package CST Microwave Studio 2010 was used as the main instrument in the investigation. Results of the investigation can contribute to the development and prototyping of an HSF-based water heater as an integral part of advanced life support system for spacecrews

  9. Exploring the potential synergistic effects of chemical disinfectants and UV on the inactivation of free-living bacteria and treatment of biofilms in a pilot-scale system.

    PubMed

    Vankerckhoven, E; Verbessem, B; Crauwels, S; Declerck, P; Muylaert, K; Willems, K A; Rediers, H

    2011-01-01

    The main objective of this study is to explore possible synergistic or additive effects of combinations of chemical disinfectants (sodium hypochlorite, peracetic acid, hydrogen peroxide, chlorine dioxide) and UV in their efficacy in inactivating free-living bacteria and removing biofilms. In contrast to most studies, this study examines disinfection of municipal water in a pilot-scale system using a mixed bacterial suspension, which enables a better simulation of the conditions encountered in actual industrial environments. It was shown that the combination of either hypochlorite, hydrogen peroxide, peracetic acid, or chlorine dioxide with UV yielded additive effects on the inactivation of free-living bacteria. Actual synergy was observed for the combination of UV and 5 ppm hydrogen peroxide. Regarding biofilm treatment, additive effects were observed using the combination of hydrogen peroxide and UV. The promising results obtained in this study indicate that the combination of UV and chemical disinfectants can considerably reduce the amount of chemicals required for the effective disinfection and treatment of biofilms.

  10. D0 Cryo Instrument Air Backup System

    SciTech Connect

    Urbin, J.; /Fermilab

    1990-11-20

    The D0 instrument air system for cryo controls has an emergency backup supply of nitrogen gas. The backup system consists of a high pressure tube trailer (38 tubes - 2400 psig MAWP), piping, valves, regulators and pressure monitoring instrumentation. The trailer is located south of DAB alongside the LN{sub 2} Dewar. Fixed piping ties to the trailer with a flex-hose. The piping follows the cryo piping bridge entering the south wall of DAB. where it passes through the pipe chase and into the cryo pump room (Rm 315). The high pressure gas is regulated down to 90 psig before tying into the compressor supplied instrument air system. Check valves are installed at the tee for the primary air and the backup N{sub 2}. Normal operating pressure for instrument air is 100-120 psig. With the backup supply pressure set to 90 psig, 'emergency air' is supplied whenever primary air pressure falls below 90 psig. There are two additional, outside connections to the system: one is a connection for repumping the trailer after a minimum backup volume is reached and the other is an auxiliary flex-hose connection for another trailer. All manual valves at system connections will be locked closed when not in use. The system's maximum allowable working pressure (MAWP) is 2400 psi, which is the trailer MAWP. All piping and components have a minimum 2400 psi working pressure. Actual component working pressures are included in the component list.

  11. Air quality and future energy system planning

    NASA Astrophysics Data System (ADS)

    Sobral Mourao, Zenaida; Konadu, Dennis; Lupton, Rick

    2016-04-01

    Ambient air pollution has been linked to an increasing number of premature deaths throughout the world. Projected increases in demand for food, energy resources and manufactured products will likely contribute to exacerbate air pollution with an increasing impact on human health, agricultural productivity and climate change. Current events such as tampering emissions tests by VW car manufacturers, failure to comply with EU Air Quality directives and WHO guidelines by many EU countries, the problem of smog in Chinese cities and new industrial emissions regulations represent unique challenges but also opportunities for regulators, local authorities and industry. However current models and practices of energy and resource use do not consider ambient air impacts as an integral part of the planing process. Furthermore the analysis of drivers, sources and impacts of air pollution is often fragmented, difficult to understand and lacks effective visualization tools that bring all of these components together. This work aims to develop a model that links impacts of air quality on human health and ecosystems to current and future developments in the energy system, industrial and agricultural activity and patterns of land use. The model will be added to the ForeseerTM tool, which is an integrated resource analysis platform that has been developed at the University of Cambridge initially with funding from BP and more recently through the EPSRC funded Whole Systems Energy Modeling (WholeSEM) project. The basis of the tool is a set of linked physical models for energy, water and land, including the technologies that are used to transform these resources into final services such as housing, food, transport and household goods. The new air quality model will explore different feedback effects between energy, land and atmospheric systems with the overarching goal of supporting better communication about the drivers of air quality and to incorporate concerns about air quality into

  12. Systemic Analysis Approaches for Air Transportation

    NASA Technical Reports Server (NTRS)

    Conway, Sheila

    2005-01-01

    Air transportation system designers have had only limited success using traditional operations research and parametric modeling approaches in their analyses of innovations. They need a systemic methodology for modeling of safety-critical infrastructure that is comprehensive, objective, and sufficiently concrete, yet simple enough to be used with reasonable investment. The methodology must also be amenable to quantitative analysis so issues of system safety and stability can be rigorously addressed. However, air transportation has proven itself an extensive, complex system whose behavior is difficult to describe, no less predict. There is a wide range of system analysis techniques available, but some are more appropriate for certain applications than others. Specifically in the area of complex system analysis, the literature suggests that both agent-based models and network analysis techniques may be useful. This paper discusses the theoretical basis for each approach in these applications, and explores their historic and potential further use for air transportation analysis.

  13. Legionnaires' Disease Outbreak at a Long-Term Care Facility Caused by a Cooling Tower Using an Automated Disinfection System--Ohio, 2013.

    PubMed

    Quinn, Celia; Demirjian, Alicia; Watkins, Louise Francois; Tomczyk, Sara; Lucas, Claressa; Brown, Ellen; Kozak-Muiznieks, Natalia; Benitez, Alvaro; Garrison, Laurel E; Kunz, Jasen; Brewer, Scott; Eitniear, Samantha; DiOrio, Mary

    2015-12-01

    On July 9, 2013, an outbreak of Legionnaires' disease (LD) was identified at Long-Term Care Facility A in central Ohio. This article describes the investigation of the outbreak and identification of the outbreak source, a cooling tower using an automated biocide delivery system. In total, 39 outbreak LD cases were identified; among these, six patients died. Water samples from a cooling tower were positive for Legionella pneumophila serogroup 1, reactive to monoclonal antibody 2, with matching sequence type to a patient isolate. An electronic control system turned off cooling tower pumps during low-demand periods, preventing delivery of disinfectant by a timed-release system, and leading to amplification of Legionella in the cooling tower. Guidelines for tower maintenance should address optimal disinfection when using automated systems. PMID:26738313

  14. Electrochemical control of iodine disinfectant for space transportation system and space station potable water

    NASA Technical Reports Server (NTRS)

    Geer, Richard D.

    1989-01-01

    An electrochemical microbial check valve method (EC-MCV) for controlling the iodine disinfectant in potable water (PW) for NASA's space operations was proposed. The factors affecting the design and performance of the unit were analyzed. This showed that it would be feasible to construct a recyclable unit in a small volume that will operate in either an iodine removal or addition mode. The EC-MCV should remove active iodine species rapidly from PW, but the rapid delivery rates at end-use may make complete removal of excess I(-) difficult under some conditions. Its performace change with AgI buildup needs to be investigated, as this controls the time for recycling the unit. The EC-MCV has advantages over the passive microbial check valve (MCV) method currently in use, as it would allow precise control of the I2 level and would not introduce excess I(-) to the water. The presence of oxygen in the EC-MCV needs to be investigated as it could affect the efficiency of I2 addition and excess I(-) removal.

  15. 49 CFR 570.57 - Air brake system and air-over-hydraulic brake subsystem.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Air brake system and air-over-hydraulic brake... STANDARDS Vehicles With GVWR of More Than 10,000 Pounds § 570.57 Air brake system and air-over-hydraulic brake subsystem. The following requirements apply to vehicles with air brake and...

  16. 30 CFR 75.1730 - Compressed air; general; compressed air systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Compressed air; general; compressed air systems... Compressed air; general; compressed air systems. (a) All pressure vessels shall be constructed, installed... Safety and Health district office. (b) Compressors and compressed-air receivers shall be equipped...

  17. 30 CFR 75.1730 - Compressed air; general; compressed air systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Compressed air; general; compressed air systems... Compressed air; general; compressed air systems. (a) All pressure vessels shall be constructed, installed... Safety and Health district office. (b) Compressors and compressed-air receivers shall be equipped...

  18. 30 CFR 75.1730 - Compressed air; general; compressed air systems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Compressed air; general; compressed air systems... Compressed air; general; compressed air systems. (a) All pressure vessels shall be constructed, installed... Safety and Health district office. (b) Compressors and compressed-air receivers shall be equipped...

  19. 30 CFR 75.1730 - Compressed air; general; compressed air systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Compressed air; general; compressed air systems... Compressed air; general; compressed air systems. (a) All pressure vessels shall be constructed, installed... Safety and Health district office. (b) Compressors and compressed-air receivers shall be equipped...

  20. 30 CFR 75.1730 - Compressed air; general; compressed air systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Compressed air; general; compressed air systems... Compressed air; general; compressed air systems. (a) All pressure vessels shall be constructed, installed... Safety and Health district office. (b) Compressors and compressed-air receivers shall be equipped...

  1. 49 CFR 570.57 - Air brake system and air-over-hydraulic brake subsystem.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... reading. (2) The air brake system compressor shall increase the air pressure in the reservoir(s) from the... time allowed for air pressure buildup shall not exceed 45 seconds. (3) The warning device (visual or audible) connected to the brake system air pressure source shall be activated when air pressure is...

  2. N-nitrosamine formation by monochloramine, free chlorine, and peracetic acid disinfection with presence of amine precursors in drinking water system.

    PubMed

    West, Danielle M; Wu, Qihua; Donovan, Ariel; Shi, Honglan; Ma, Yinfa; Jiang, Hua; Wang, Jianmin

    2016-06-01

    In this study, the formation of eight N-nitrosamines, N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine, N-nitrosomethylamine, N-nitrosodi-n-propylamine, N-nitrosodi-n-butylamine, N-Nitrosopiperidine, N-Nitrosopyrrolidine, N-Nitrosomorpholine, were systematically evaluated with respect to seven N-nitrosamine precursors (dimethylamine, trimethylamine, 3-(dimethylaminomethyl)indole, 4-dimethylaminoantipyrine, ethylmethylamine, diethylamine, dipropylamine) and three disinfectants (monochloramine, free chlorine, peracetic acid) under variable dosages, exposure times, and pH in a drinking water system. Without the presence of the seven selected N-nitrosamine precursors N-nitrosamine formation was not observed under any tested condition except very low levels of N-Nitrosopyrrolidine under some conditions. With selected N-nitrosamine precursors present N-nitrosamines formed at different levels under different conditions. The highest N-nitrosamine formation was NDMA with a maximum concentration of 1180 ng/L by monochloramine disinfection with precursors present; much lower levels of N-nitrosamines were formed by free chlorine disinfection; and no detectable level of N-nitrosamines were observed by peracetic acid disinfection except low level of N-Nitrosodi-n-propylamine under some conditions. NDMA formation was not affected by pH while four other N-nitrosamine formations were slightly affected by sample pH tested between 7 and 9, with formation decreasing with increasing pH. Monochloramine exposure time study displayed fast formation of N-nitrosamines, largely formed in four hours of exposure and maximized after seven days. This was a systematic study on the N-nitrosamine formation with the seven major N-nitrosamine precursors presence and absence under different conditions, including peracetic acid disinfection which has not been studied elsewhere.

  3. N-nitrosamine formation by monochloramine, free chlorine, and peracetic acid disinfection with presence of amine precursors in drinking water system.

    PubMed

    West, Danielle M; Wu, Qihua; Donovan, Ariel; Shi, Honglan; Ma, Yinfa; Jiang, Hua; Wang, Jianmin

    2016-06-01

    In this study, the formation of eight N-nitrosamines, N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine, N-nitrosomethylamine, N-nitrosodi-n-propylamine, N-nitrosodi-n-butylamine, N-Nitrosopiperidine, N-Nitrosopyrrolidine, N-Nitrosomorpholine, were systematically evaluated with respect to seven N-nitrosamine precursors (dimethylamine, trimethylamine, 3-(dimethylaminomethyl)indole, 4-dimethylaminoantipyrine, ethylmethylamine, diethylamine, dipropylamine) and three disinfectants (monochloramine, free chlorine, peracetic acid) under variable dosages, exposure times, and pH in a drinking water system. Without the presence of the seven selected N-nitrosamine precursors N-nitrosamine formation was not observed under any tested condition except very low levels of N-Nitrosopyrrolidine under some conditions. With selected N-nitrosamine precursors present N-nitrosamines formed at different levels under different conditions. The highest N-nitrosamine formation was NDMA with a maximum concentration of 1180 ng/L by monochloramine disinfection with precursors present; much lower levels of N-nitrosamines were formed by free chlorine disinfection; and no detectable level of N-nitrosamines were observed by peracetic acid disinfection except low level of N-Nitrosodi-n-propylamine under some conditions. NDMA formation was not affected by pH while four other N-nitrosamine formations were slightly affected by sample pH tested between 7 and 9, with formation decreasing with increasing pH. Monochloramine exposure time study displayed fast formation of N-nitrosamines, largely formed in four hours of exposure and maximized after seven days. This was a systematic study on the N-nitrosamine formation with the seven major N-nitrosamine precursors presence and absence under different conditions, including peracetic acid disinfection which has not been studied elsewhere. PMID:27037659

  4. Computational modeling of ultraviolet disinfection.

    PubMed

    Younis, B A; Yang, T H

    2010-01-01

    The efficient design of ultraviolet light (UV) systems for water and wastewater treatment requires detailed knowledge of the patterns of fluid motion that occur in the disinfection channel. This knowledge is increasingly being obtained using Computational Fluid Dynamics (CFD) software packages that solve the equations governing turbulent fluid-flow motion. In this work, we present predictions of the patterns of flow and the extent of disinfection in a conventional reactor consisting of an open channel with an array of UV lamps placed with their axes perpendicular to the direction of flow. It is shown that the resulting flow is inherently unsteady due to the regular shedding of vortices from the submerged lamps. It is also shown that the accurate prediction of the hydraulic residence time and, consequently, the extent of disinfection is strongly dependent on the ability of the CFD method to capture the occurrence and strength of the vortex shedding, and its effects on the turbulent mixing processes.

  5. Disinfection of Bacillus spores with acidified nitrite.

    PubMed

    Szabo, Jeffrey G; Adcock, Noreen J; Rice, Eugene W

    2014-10-01

    Disinfecting water generated from a bioterrorism contamination event will require large amounts of disinfectant since the volume of water flushed from a drinking water distribution system or wash water collected from a contaminated outdoor area can accumulate quickly. Commonly used disinfectants may be unavailable in the necessary amounts, so evaluation of alternative disinfectants is needed. This study focuses on disinfection of Bacillus spores in water using acidified nitrite. The effect of varying pH (2 or 3), temperature (5°C or 24°C), nitrite concentration (0.01 or 0.1M), buffer (Butterfields or Phosphate Buffered Saline, PBS) and Bacillus species (B. globigii and B. anthracis Sterne) was evaluated. B. globigii was more resistant to disinfection under all water quality conditions. Disinfection was more effective for B. globigii and B. anthracis Sterne at 0.1M nitrite, pH 2, and 24°C. Disinfection of B. anthracis Sterne was enhanced in low ionic strength Butterfields buffer compared to PBS.

  6. Proteomic Adaptations to Starvation Prepare Escherichia coli for Disinfection Tolerance

    PubMed Central

    Du, Zhe; Nandakumar, Renu; Nickerson, Kenneth; Li, Xu

    2015-01-01

    Despite the low nutrient level and constant presence of secondary disinfectants, bacterial re-growth still occurs in drinking water distribution systems. The molecular mechanisms that starved bacteria use to survive low-level chlorine-based disinfectants are not well understood. The objective of this study is to investigate these molecular mechanisms at the protein level that prepare starved cells for disinfection tolerance. Two commonly used secondary disinfectants chlorine and monochloramine, both at 1 mg/L, were used in this study. The proteomes of normal and starved Escherichia coli (K12 MG1655) cells were studied using quantitative proteomics. Over 60-min disinfection, starved cells showed significantly higher disinfection tolerance than normal cells based on the inactivation curves for both chlorine and monochloramine. Proteomic analyses suggest that starvation may prepare cells for the oxidative stress that chlorine-based disinfection will cause by affecting glutathione metabolism. In addition, proteins involved in stress regulation and stress responses were among the ones up-regulated under both starvation and chlorine/monochloramine disinfection. By comparing the fold changes under different conditions, it is suggested that starvation prepares E. coli for disinfection tolerance by increasing the expression of enzymes that can help cells survive chlorine/monochloramine disinfection. Protein co-expression analyses show that proteins in glycolysis and pentose phosphate pathway that were up-regulated under starvation are also involved in disinfection tolerance. Finally, the production and detoxification of methylglyoxal may be involved in the chlorine-based disinfection and cell defense mechanisms. PMID:25463932

  7. Molecular optical air data system (MOADS)

    NASA Astrophysics Data System (ADS)

    Tchoryk, Peter, Jr.; Watkins, Christopher B.; Lindemann, Scott K.; Hays, Paul B.; Nardell, Carl A.

    2001-09-01

    The Molecular Optical Air Data System (MOADS) is a compact optical instrument that can directly measure wind speed and direction, density, and temperature of the air surrounding an aircraft. From these measurements, a complete set of air data products can be determined. Single-axis wind tunnel testing of wind speed and density has just been completed for the current prototype. These wind tunnel measurements have shown that the current prototype meets wind speed accuracy predictions and initial results from density testing indicate a high level of correlation with absolute pressure transducer measurements. A preliminary design for the next generation instrument, the Joint Optical Air Data System (JOADS), has been completed and is intended to meet Joint Striker Fighter (JSF) requirements. Work is also underway to evaluate the application of MOADS to Unmanned Air Vehicles (UAVs), Reusable Launch Vehicles (RLVs), helicopters and weapon systems. Extensions of MOADS technology to wind shear, gust alleviation, and clear air turbulence detection for commercial aircraft are also being pursued. The basic instrument operation, preliminary ground testing (wind tunnel) results, comparison of these results to simulations, next generation instrument capabilities, and plans for a flight demonstration are discussed.

  8. ULTRAVIOLET (UV) DISINFECTION SYSTEMS FOR SECONDARY WASTEWATER EFFLUENT AND WATER REUSE

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) Environmental Technology Verification (ETV) program evaluates the performance of innovative air, water, pollution prevention and monitoring technologies that have the potential to improve human health and the environment. This techn...

  9. Advanced Overfire Air system and design

    SciTech Connect

    Gene berkau

    2004-07-30

    The objective of the proposed project is to design, install and optimize a prototype advanced tangential OFA air system on two mass feed stoker boilers that can burn coal, biomass and a mixture of these fuels. The results will be used to develop a generalized methodology for retrofit designs and optimization of advanced OFA air systems. The advanced OFA system will reduce particulate and NOx emissions and improve overall efficiency by reducing carbon in the ash and excess oxygen. The advanced OFA will also provide capabilities for carrying full load and improved load following and transitional operations.

  10. Reductive dehalogenation of disinfection byproducts by an activated carbon-based electrode system.

    PubMed

    Li, Yuanqing; Kemper, Jerome M; Datuin, Gwen; Akey, Ann; Mitch, William A; Luthy, Richard G

    2016-07-01

    Low molecular weight, uncharged, halogenated disinfection byproducts (DBPs) are poorly removed by the reverse osmosis and advanced oxidation process treatment units often applied for further treatment of municipal wastewater for potable reuse. Granular activated carbon (GAC) treatment effectively sorbed 22 halogenated DBPs. Conversion of the GAC to a cathode within an electrolysis cell resulted in significant degradation of the 22 halogenated DBPs by reductive electrolysis at -1 V vs. Standard Hydrogen Electrode (SHE). The lowest removal efficiency over 6 h electrolysis was for trichloromethane (chloroform; 47%) but removal efficiencies were >90% for 13 of the 22 DBPs. In all cases, DBP degradation was higher than in electrolysis-free controls, and degradation was verified by the production of halides as reduction products. Activated carbons and charcoal were more effective than graphite for electrolysis, with graphite featuring poor sorption for the DBPs. A subset of halogenated DBPs (e.g., haloacetonitriles, chloropicrin) were degraded upon sorption to the GAC, even without electrolysis. Using chloropicrin as a model, experiments indicated that this loss was attributable to the partial reduction of sorbed chloropicrin from reducing equivalents in the GAC. Reducing equivalents depleted by these reactions could be restored when the GAC was treated by reductive electrolysis. GAC treatment of an advanced treatment train effluent for potable reuse effectively reduced the concentrations of chloroform, bromodichloromethane and dichloroacetonitrile measured in the column influent to below the method detection limits. Treatment of the GAC by reductive electrolysis at -1 V vs. SHE over 12 h resulted in significant degradation of the chloroform (63%), bromodichloromethane (96%) and dichloroacetonitrile (99%) accumulated on the GAC. The results suggest that DBPs in advanced treatment train effluents could be captured and degraded continuously by reductive electrolysis

  11. Real-time ArcGIS and heterotrophic plate count based chloramine disinfectant control in water distribution system.

    PubMed

    Bai, Xiaohui; Zhi, Xinghua; Zhu, Huifeng; Meng, Mingqun; Zhang, Mingde

    2015-01-01

    This study investigates the effect of chloramine residual on bacteria growth and regrowth and the relationship between heterotrophic plate counts (HPCs) and the concentration of chloramine residual in the Shanghai drinking water distribution system (DWDS). In this study, models to control HPCs in the water distribution system and consumer taps are also developed. Real-time ArcGIS was applied to show the distribution and changed results of the chloramine residual concentration in the pipe system by using these models. Residual regression analysis was used to get a reasonable range of the threshold values that allows the chloramine residual to efficiently inhibit bacteria growth in the Shanghai DWDS; the threshold values should be between 0.45 and 0.5 mg/L in pipe water and 0.2 and 0.25 mg/L in tap water. The low residual chloramine value (0.05 mg/L) of the Chinese drinking water quality standard may pose a potential health risk for microorganisms that should be improved. Disinfection by-products (DBPs) were detected, but no health risk was identified.

  12. Evaluation of disinfection efficacy and chemical formation using MPUV ballast water treatment system (GloEn-Patrol).

    PubMed

    Jung, Yeon Jung; Yoon, Yeojoon; Pyo, Tae Sung; Lee, Soo-Tae; Shin, Kyoungsoon; Kang, Joon-Wun

    2012-09-01

    This study was undertaken to evaluate the efficacy of inactivation of several indigenous marine species and the formation of oxidants and other by-products using medium-pressure ultraviolet (MPUV) ballast water treatment. The ballast water treatment system (BWTS) used in this study was composed of filtration modules as a pretreatment process, followed by a UV irradiation process equipped with a polychromatic MPUV lamp. The experiments were performed on seawater (Busan, >32 PSU) and brackish water (Nakdong River, 20-22 PSU) with flow rates of 50 and 250 m(3)/h. The disinfection efficacy of the system was evaluated using indigenous species (>50 microm and 10-50 microm) and surrogate microorganisms (E. coli and Enterococci group). The test results successfully met the D-2 regulation of the IMO (International Marine Organization). In addition, oxidants, such as H202, total residual oxidants (TRO) and OH radicals, and potential halogenated by-products, such as haloacetic acids, trihalomethanes and total organic halides, that had potentially formed after MPUV treatment, were measured. In conclusion, the ballast water treatment system employing the MPUV physical process not only effectively eliminated indigenous species in ballast water but also generated no harmful by-products.

  13. Recycled Water Poses Disinfectant Problem

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1973

    1973-01-01

    Discusses the possible health hazards resulting from released nucleic acid of inactivated viruses, chlorinated nonliving organic molecules, and overestimated reliability of waste treatment standards. Suggests the recycle system use a dual disinfectant such as chlorine and ozone in water treatment. (CC)

  14. The Integrated Air Transportation System Evaluation Tool

    NASA Technical Reports Server (NTRS)

    Wingrove, Earl R., III; Hees, Jing; Villani, James A.; Yackovetsky, Robert E. (Technical Monitor)

    2002-01-01

    Throughout U.S. history, our nation has generally enjoyed exceptional economic growth, driven in part by transportation advancements. Looking forward 25 years, when the national highway and skyway systems are saturated, the nation faces new challenges in creating transportation-driven economic growth and wealth. To meet the national requirement for an improved air traffic management system, NASA developed the goal of tripling throughput over the next 20 years, in all weather conditions while maintaining safety. Analysis of the throughput goal has primarily focused on major airline operations, primarily through the hub and spoke system.However, many suggested concepts to increase throughput may operate outside the hub and spoke system. Examples of such concepts include the Small Aircraft Transportation System, civil tiltrotor, and improved rotorcraft. Proper assessment of the potential contribution of these technologies to the domestic air transportation system requires a modeling capability that includes the country's numerous smaller airports, acting as a fundamental component of the National Air space System, and the demand for such concepts and technologies. Under this task for NASA, the Logistics Management Institute developed higher fidelity demand models that capture the interdependence of short-haul air travel with other transportation modes and explicitly consider the costs of commercial air and other transport modes. To accomplish this work, we generated forecasts of the distribution of general aviation based aircraft and GA itinerant operations at each of nearly 3.000 airport based on changes in economic conditions and demographic trends. We also built modules that estimate the demand for travel by different modes, particularly auto, commercial air, and GA. We examined GA demand from two perspectives: top-down and bottom-up, described in detail.

  15. Engine powered auxiliary air supply system

    SciTech Connect

    Mc Lean, J.R.

    1987-01-27

    This patent describes an auxiliary air supply system comprising: an engine; at least one exhaust driven turbocharger including a turbine and a compressor associated therewith for supply of compressed air to the engine; a low pressure compressor including means for powering the low pressure compressor utilizing the engine exhaust gas and flow connected to receive a portion of the compressed air exiting the engine turbocharger compressor; a high pressure compressor including means for powering the high pressure compressor utilizing the engine exhaust gas and flow connected to receive the compressed air exiting the low pressure compressor; and means for directing engine exhaust gases between at least one engine turbocharger and the means for powering the low and high pressure compressors.

  16. Disinfection of football protective equipment using chlorine dioxide produced by the ICA TriNova system

    PubMed Central

    Newsome, Anthony L; DuBois, John D; Tenney, Joel D

    2009-01-01

    Backround Community-associated methicillin-resistant Staphylococcus aureus outbreaks have occurred in individuals engaged in athletic activities such as wrestling and football. Potential disease reduction interventions include the reduction or elimination of bacteria on common use items such as equipment. Chlorine dioxide has a long history of use as a disinfectant. The purpose of this investigation was to evaluate the ability of novel portable chlorine dioxide generation devices to eliminate bacteria contamination of helmets and pads used by individuals engaged in football. Methods In field studies, the number of bacteria associated with heavily used football helmets and shoulder pads was determined before and after overnight treatment with chlorine dioxide gas. Bacteria were recovered using cotton swabs and plated onto trypticase soy agar plates. In laboratory studies, Staphylococcus aureus was applied directly to pads. The penetration of bacteria into the pads was determined by inoculating agar plates with portions of the pads taken from the different layers of padding. The ability to eliminate bacteria on the pad surface and underlying foam layers after treatment with chlorine dioxide was also determined. Results Rates of recovery of bacteria after treatment clearly demonstrated that chlorine dioxide significantly (p < 0.001) reduce and eliminated bacteria found on the surface of pads. For example, the soft surface of shoulder pads from a university averaged 2.7 × 103 recoverable bacteria colonies before chlorine dioxide treatment and 1.3 × 102 recoverable colonies after treatment. In addition, the gas was capable of penetrating the mesh surface layer and killing bacteria in the underlying foam pad layers. Here, 7 × 103 to 4.5 × 103 laboratory applied S. aureus colonies were recovered from underlying layers before treatment and 0 colonies were present after treatment. Both naturally occurring bacteria and S. aureus were susceptible to the treatment process

  17. Combined air and water pollution control system

    NASA Technical Reports Server (NTRS)

    Wolverton, Billy C. (Inventor); Jarrell, Lamont (Inventor)

    1990-01-01

    A bioaquatic air pollution control system for controlling both water and atmospheric pollution is disclosed. The pollution control system includes an exhaust for directing polluted gases out of a furnace and a fluid circulating system which circulates fluid, such as waste water, from a source, past the furnace where the fluid flow entrains the pollutants from the furnace. The combined fluid and pollutants are then directed through a rock/plant/microbial filtering system. A suction pump pumps the treated waste water from the filter system past the exhaust to again entrain more pollutants from the furnace where they are combined with the fluid (waste water) and directed to the filter system.

  18. Secondary air injection system and method

    SciTech Connect

    Wu, Ko-Jen; Walter, Darrell J.

    2014-08-19

    According to one embodiment of the invention, a secondary air injection system includes a first conduit in fluid communication with at least one first exhaust passage of the internal combustion engine and a second conduit in fluid communication with at least one second exhaust passage of the internal combustion engine, wherein the at least one first and second exhaust passages are in fluid communication with a turbocharger. The system also includes an air supply in fluid communication with the first and second conduits and a flow control device that controls fluid communication between the air supply and the first conduit and the second conduit and thereby controls fluid communication to the first and second exhaust passages of the internal combustion engine.

  19. Advanced Air Data Systems for Commercial Aircraft

    NASA Technical Reports Server (NTRS)

    2006-01-01

    It is possible to get a crude estimate of wind speed and direction while driving a car at night in the rain, with the motion of the raindrop reflections in the headlights providing clues about the wind. The clues are difficult to interpret, though, because of the relative motions of ground, car, air, and raindrops. More subtle interpretation is possible if the rain is replaced by fog, because the tiny droplets would follow the swirling currents of air around an illuminated object, like, for example, a walking pedestrian. Microscopic particles in the air (aerosols) are better for helping make assessments of the wind, and reflective air molecules are best of all, providing the most refined measurements. It takes a bright light to penetrate fog, so it is easy to understand how other factors, like replacing the headlights with the intensity of a searchlight, can be advantageous. This is the basic principle behind a lidar system. While a radar system transmits a pulse of radiofrequency energy and interprets the received reflections, a lidar system works in a similar fashion, substituting a near-optical laser pulse. The technique allows the measurement of relative positions and velocities between the transmitter and the air, which allows measurements of relative wind and of air temperature (because temperature is associated with high-frequency random motions on a molecular level). NASA, as well as the National Oceanic and Atmospheric Administration (NOAA), have interests in this advanced lidar technology, as much of their explorative research requires the ability to measure winds and turbulent regions within the atmosphere. Lidar also shows promise for providing warning of turbulent regions within the National Airspace System to allow commercial aircraft to avoid encounters with turbulence and thereby increase the safety of the traveling public. Both agencies currently employ lidar and optical sensing for a variety of weather-related research projects, such as analyzing

  20. Evaluating Radionuclide Air Emission Stack Sampling Systems

    SciTech Connect

    Ballinger, Marcel Y.

    2002-12-16

    The Pacific Northwest National Laboratory (PNNL) operates a number of research and development (R&D) facilities for the U.S. Department of Energy at the Hanford Site, Washington. These facilities are subject to Clean Air Act regulations that require sampling of radionuclide air emissions from some of these facilities. A revision to an American National Standards Institute (ANSI) standard on sampling radioactive air emissions has recently been incorporated into federal and state regulations and a re-evaluation of affected facilities is being performed to determine the impact. The revised standard requires a well-mixed sampling location that must be demonstrated through tests specified in the standard. It also carries a number of maintenance requirements, including inspections and cleaning of the sampling system. Evaluations were performed in 2000 – 2002 on two PNNL facilities to determine the operational and design impacts of the new requirements. The evaluation included inspection and cleaning maintenance activities plus testing to determine if the current sampling locations meet criteria in the revised standard. Results show a wide range of complexity in inspection and cleaning activities depending on accessibility of the system, ease of removal, and potential impact on building operations (need for outages). As expected, these High Efficiency Particulate Air (HEPA)-filtered systems did not show deposition significant enough to cause concerns with blocking of the nozzle or other parts of the system. The tests for sampling system location in the revised standard also varied in complexity depending on accessibility of the sample site and use of a scale model can alleviate many issues. Previous criteria to locate sampling systems at eight duct diameters downstream and two duct diameters upstream of the nearest disturbances is no guarantee of meeting criteria in the revised standard. A computational fluid dynamics model was helpful in understanding flow and

  1. 14 CFR 23.1091 - Air induction system.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Air induction system. 23.1091 Section 23... § 23.1091 Air induction system. (a) The air induction system for each engine and auxiliary power unit and their accessories must supply the air required by that engine and auxiliary power unit and...

  2. 14 CFR 23.1091 - Air induction system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Air induction system. 23.1091 Section 23... § 23.1091 Air induction system. (a) The air induction system for each engine and auxiliary power unit and their accessories must supply the air required by that engine and auxiliary power unit and...

  3. 30 CFR 77.412 - Compressed air systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Compressed air systems. 77.412 Section 77.412... for Mechanical Equipment § 77.412 Compressed air systems. (a) Compressors and compressed-air receivers... involving the pressure system of compressors, receivers, or compressed-air-powered equipment shall not...

  4. 30 CFR 77.412 - Compressed air systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Compressed air systems. 77.412 Section 77.412... for Mechanical Equipment § 77.412 Compressed air systems. (a) Compressors and compressed-air receivers... involving the pressure system of compressors, receivers, or compressed-air-powered equipment shall not...

  5. 30 CFR 77.412 - Compressed air systems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Compressed air systems. 77.412 Section 77.412... for Mechanical Equipment § 77.412 Compressed air systems. (a) Compressors and compressed-air receivers... involving the pressure system of compressors, receivers, or compressed-air-powered equipment shall not...

  6. 30 CFR 77.412 - Compressed air systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Compressed air systems. 77.412 Section 77.412... for Mechanical Equipment § 77.412 Compressed air systems. (a) Compressors and compressed-air receivers... involving the pressure system of compressors, receivers, or compressed-air-powered equipment shall not...

  7. 30 CFR 77.412 - Compressed air systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Compressed air systems. 77.412 Section 77.412... for Mechanical Equipment § 77.412 Compressed air systems. (a) Compressors and compressed-air receivers... involving the pressure system of compressors, receivers, or compressed-air-powered equipment shall not...

  8. Ultraviolet disinfection of contact lenses.

    PubMed

    Harris, M G; Fluss, L; Lem, A; Leong, H

    1993-10-01

    To evaluate the efficacy of ultraviolet (UV) radiation as a method of disinfecting contact lenses and their storage solutions, we contaminated soft lenses (Bausch & Lomb Optima 38), rigid gas permeable (RGP) lenses (Oxyflow F-30), and their storage solutions with three common bacteria. Escherichia coli (E.c.), Staphylococcus epidermis (S.e.), and Serratia marcescens (S.m.). The storage solutions used were saline solution and RGP conditioning solution. We determined the exposure times to 253.7-nm wavelength UV radiation necessary to disinfect the contact lenses and solutions. The decimal reduction values (D values) found for UV radiation were 10 to 200 hundred times shorter than reported for currently available disinfection systems. For E.c., sterilization was attained after 100 s of exposure. For S.e. and S.m., sterilization occurred after 300 s of exposure. Different contact lens solutions transmit UV radiation to various degrees, with saline solution passing more than 90% of the UV radiation. Thus, our results indicate that UV radiation is an effective and rapid method of disinfecting contact lenses and their storage solutions. PMID:8247487

  9. Ultraviolet disinfection of contact lenses.

    PubMed

    Harris, M G; Fluss, L; Lem, A; Leong, H

    1993-10-01

    To evaluate the efficacy of ultraviolet (UV) radiation as a method of disinfecting contact lenses and their storage solutions, we contaminated soft lenses (Bausch & Lomb Optima 38), rigid gas permeable (RGP) lenses (Oxyflow F-30), and their storage solutions with three common bacteria. Escherichia coli (E.c.), Staphylococcus epidermis (S.e.), and Serratia marcescens (S.m.). The storage solutions used were saline solution and RGP conditioning solution. We determined the exposure times to 253.7-nm wavelength UV radiation necessary to disinfect the contact lenses and solutions. The decimal reduction values (D values) found for UV radiation were 10 to 200 hundred times shorter than reported for currently available disinfection systems. For E.c., sterilization was attained after 100 s of exposure. For S.e. and S.m., sterilization occurred after 300 s of exposure. Different contact lens solutions transmit UV radiation to various degrees, with saline solution passing more than 90% of the UV radiation. Thus, our results indicate that UV radiation is an effective and rapid method of disinfecting contact lenses and their storage solutions.

  10. 21. DETAIL OF AIR HANDLER 1 (MST AIRCONDITIONING SYSTEM) INTERIOR, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. DETAIL OF AIR HANDLER 1 (MST AIR-CONDITIONING SYSTEM) INTERIOR, SOUTHEAST CORNER, STATION 30, SLC-3W MST - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  11. Fuel-air ratio controlled carburetion system

    SciTech Connect

    Abbey, H. G.

    1980-02-12

    An automatic control system is disclosed supplying a fuel-air mixture to an internal combustion engine including a variable-venturi carburetor. Air is fed into the input of the venturi, the air passing through the throat thereof whose effective area is adjusted by a mechanism operated by a servo motor. Fuel is fed into the input of the venturi from a fuel reservoir through a main path having a fixed orifice and an auxiliary path formed by a metering valve operated by an auxiliary fuel-control motor. The differential air pressure developed between the inlet of the venturi and the throat thereof is sensed to produce an airvelocity command signal that is applied to a controller adapted to compare the command signal with the servo motor set point to produce an output for governing the servo motor to cause it to seek a null point, thereby defining a closed process control loop. The intake manifold vacuum, which varies in degree as a function of load and speed conditions is sensed to govern the auxiliary fuel-control motor accordingly, is at the same time converted into an auxiliary signal which is applied to the controller in the closed loop to modulate the command signal in a manner establishing an optimum air-fuel ratio under the varying conditions of load and speed.

  12. A warm air poultry brooding system

    SciTech Connect

    Nulte, W.H.

    1980-12-01

    As the energy crisis escalated during the mid-70's, it became apparent that energy intensive industries must seek alternate fuel sources. Georgia Tech realized that one of these industries was the poultry industry. Consequently, a demonstration project of a wood-fired, warm air poultry brooding system was designed and built. Since its completion in mid-1978, the system has demonstrated considerable cost savings as well as being a very functional and reliable system. The system consists of 3 main components--a wood burning furnace, a supply distribution and return duct, and 20 flexible ducts which simulate the function of the propane brooders by providing warm air close to the ground. A separate structure houses the furnace and wood supply. This house is located at the midpoint of the growout house to allow symmetrical and naturally balanced air distribution. Since the system became operational, 16 flocks of birds have been brooded. During this time, wood usage has averaged approximately 30 cords per year while in a neighboring house, that is used as a control house, the propane usage has averaged 3,800 gallons per year. In the area of Georgia where the demonstration project is located, the cost of fuelwood has remained stable over the last 2 years, whereas the price of propane has continually increased. Thus the grower has the benefit of constantly increasing cost savings while utilizing a renewable resource as fuel.

  13. Disinfection. [Wastewater treatment

    SciTech Connect

    Haas, C.N.; McCreary, J.J.

    1982-06-01

    Methods of disinfection of wastewater including chlorination, ultraviolet radiation, ozone, and quaternary compounds are reviewed. Various analytical methods to detect residues of the disinfectants are described. The production of inorganic and nonvolatile organic compounds in conventional water treatment processes is reviewed. (KRM)

  14. 14 CFR 23.1111 - Turbine engine bleed air system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Turbine engine bleed air system. 23.1111 Section 23.1111 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Induction System § 23.1111 Turbine engine bleed air system. For turbine engine bleed air systems,...

  15. 14 CFR 23.1111 - Turbine engine bleed air system.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Turbine engine bleed air system. 23.1111 Section 23.1111 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Induction System § 23.1111 Turbine engine bleed air system. For turbine engine bleed air systems,...

  16. 14 CFR 23.1091 - Air induction system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Air induction system. 23.1091 Section 23... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant Induction System § 23.1091 Air induction system. (a) The air induction system for each engine and auxiliary power...

  17. 14 CFR 23.1111 - Turbine engine bleed air system.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Turbine engine bleed air system. 23.1111 Section 23.1111 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Induction System § 23.1111 Turbine engine bleed air system. For turbine engine bleed air systems,...

  18. 14 CFR 23.1111 - Turbine engine bleed air system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Turbine engine bleed air system. 23.1111 Section 23.1111 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Induction System § 23.1111 Turbine engine bleed air system. For turbine engine bleed air systems,...

  19. 14 CFR 23.1111 - Turbine engine bleed air system.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Turbine engine bleed air system. 23.1111 Section 23.1111 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Induction System § 23.1111 Turbine engine bleed air system. For turbine engine bleed air systems,...

  20. 14 CFR 23.1109 - Turbocharger bleed air system.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Turbocharger bleed air system. 23.1109... Induction System § 23.1109 Turbocharger bleed air system. The following applies to turbocharged bleed air... contamination following any probable failure of the turbocharger or its lubrication system. (b) The...

  1. 14 CFR 23.1109 - Turbocharger bleed air system.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Turbocharger bleed air system. 23.1109... Induction System § 23.1109 Turbocharger bleed air system. The following applies to turbocharged bleed air... contamination following any probable failure of the turbocharger or its lubrication system. (b) The...

  2. 14 CFR 23.1109 - Turbocharger bleed air system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Turbocharger bleed air system. 23.1109... Induction System § 23.1109 Turbocharger bleed air system. The following applies to turbocharged bleed air... contamination following any probable failure of the turbocharger or its lubrication system. (b) The...

  3. 14 CFR 23.1109 - Turbocharger bleed air system.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Turbocharger bleed air system. 23.1109... Induction System § 23.1109 Turbocharger bleed air system. The following applies to turbocharged bleed air... contamination following any probable failure of the turbocharger or its lubrication system. (b) The...

  4. 14 CFR 23.1109 - Turbocharger bleed air system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Turbocharger bleed air system. 23.1109... Induction System § 23.1109 Turbocharger bleed air system. The following applies to turbocharged bleed air... contamination following any probable failure of the turbocharger or its lubrication system. (b) The...

  5. Air Force geographic information and analysis system

    SciTech Connect

    Henney, D.A.; Jansing, D.S.; Durfee, R.C.; Margle, S.M.; Till, L.E.

    1987-01-01

    A microcomputer-based geographic information and analysis system (GIAS) was developed to assist Air Force planners with environmental analysis, natural resources management, and facility and land-use planning. The system processes raster image data, topological data structures, and geometric or vector data similar to that produced by computer-aided design and drafting (CADD) systems, integrating the data where appropriate. Data types included Landsat imagery, scanned images of base maps, digitized point and chain features, topographic elevation data, USGS stream course data, highway networks, railroad networks, and land use/land cover information from USGS interpreted aerial photography. The system is also being developed to provide an integrated display and analysis capability with base maps and facility data bases prepared on CADD systems. 3 refs.

  6. Controlling Disinfection Residual Losses in Drinking Water Distribution Systems: Results from Experimental Studies

    EPA Science Inventory

    It is generally accepted that water quality can deteriorate in a distribution system through reactions in the bulk phase and/or at the pipe wall. These reactions may be physical, chemical and/or microbiological in nature. Perhaps one of the most serious aspects of water quality...

  7. CONTROLLING DISINFECTION BY-PRODUCTS (DBPS) AND MICROBIAL CONTAMINANTS IN SMALL PUBLIC WATER SYSTEMS (PWS)

    EPA Science Inventory

    The purpose of this chaper is to describe the in-house and field research activities specifically designed to evaluate alternative treatment technologies for small community and non-community water systems. The discussion is comprised of four major sections: (1) Particulate Remo...

  8. Controlling Disinfection Residual Losses in Drinking Water Distribution Systems: Results from Experimental Studies

    EPA Science Inventory

    It has become generally accepted that water quality can deteriorate in a distribution system through reactions in the bulk phase and/or at the pipe wall. These reactions may be physical, chemical and/or microbiological in nature. Perhaps one of the most serious aspects of water...

  9. Wood stove with safety forced air system

    SciTech Connect

    Erickson, A.J.; Thulman, R.D.

    1982-08-03

    A high efficiency, air-tight wood stove has a firebox with front, side, rear, top and bottom walls, primary air introducing means for admitting combustion air into the firebox, air flow means adjacent the bottom of the firebox for directing a flow of air upwardly across at least one firebox wall, at least one supplemental air inlet for diverting a portion of the air from the air flow means into the firebox, fan means for forcing air through the air flow means and through the supplemental air inlet, the size of the primary air introducing means being chosen to automatically restrict the combustion in the firebox if the fan means stops to maintain the temperature of the stove and surroundings at safe levels.

  10. Electrochemical air revitalization system optimization investigation

    NASA Technical Reports Server (NTRS)

    Woods, R. R.; Schubert, F. H.; Hallick, T. M.

    1975-01-01

    A program to characterize a Breadboard of an Electrochemical Air Revitalization System (BEARS) was successfully completed. The BEARS is composed of three components: (1) a water vapor electrolysis module (WVEM) for O2 production and partial humidity control, (2) an electrochemical depolarized carbon dioxide concentrator module (EDCM) for CO2 control, and (3) a power-sharing controller, designed to utilize the power produced by the EDCM to partially offset the WVEM power requirements. It is concluded from the results of this work that the concept of electrochemical air revitalization with power-sharing is a viable solution to the problem of providing a localized topping force for O2 generation, CO2 removal and partial humidity control aboard manned spacecraft. Continued development of the EARS concept is recommended, applying the operational experience and limits identified during the BEARS program to testing of a one-man capacity system and toward the development of advanced system controls to optimize EARS operation for given interfaces and requirements. Successful completion of this development will produce timely technology necessary to plan future advanced environmental control and life support system programs and experiments.

  11. Assessment of disinfectants in explosive destruction system for biological agent destruction : LDRD final report FY04.

    SciTech Connect

    Simmons, Blake Alexander; Didlake, John E. Jr.; Bradshaw, Robert W.; Crooker, Paul J.; Buffleben, George M.

    2005-01-01

    Treatment systems that can neutralize biological agents are needed to mitigate risks from novel and legacy biohazards. Tests with Bacillus thuringiensis and Bacillus steurothemophilus spores were performed in a 190-liter, 1-112 lb TNT equivalent rated Explosive Destruction System (EDS) system to evaluate its capability to treat and destroy biological agents. Five tests were conducted using three different agents to kill the spores. The EDS was operated in steam autoclave, gas fumigation and liquid decontamination modes. The first three tests used EDS as an autoclave, which uses pressurized steam to kill the spores. Autoclaving was performed at 130-140 deg C for up to 2-hours. Tests with chlorine dioxide at 750 ppm concentration for 1 hour and 10% (vol) aqueous chlorine bleach solution for 1 hour were also performed. All tests resulted in complete neutralization of the bacterial spores based on no bacterial growth in post-treatment incubations. Explosively opening a glass container to expose the bacterial spores for treatment with steam was demonstrated and could easily be done for chlorine dioxide gas or liquid bleach.

  12. Oxidation of disinfectants with Cl-substituted structure by a Fenton-like system Cu(2+)/H2O2 and analysis on their structure-reactivity relationship.

    PubMed

    Peng, Jianbiao; Li, Jianhua; Shi, Huanhuan; Wang, Zunyao; Gao, Shixiang

    2016-01-01

    As widely used chemicals intended to protect human being from infection of microorganisms, disinfectants are ubiquitous in the environment. Among them chlorine-substituted phenol is a basic structure in many disinfectant molecules. Removal of these pollutants from wastewater is of great concern. The oxidative degradation of antimicrobial agents such as triclosan, chlorofene, and dichlorofene by a Fenton-like system Cu(2+)/H2O2 was examined. Reaction conditions such as temperature, initial concentrations of H2O2 and Cu(2+), and pH were optimized using triclosan as a representative. The degradation kinetics of the above disinfectants followed pseudo-first-order kinetics under the investigated conditions. Fourteen chlorophenols (CPs) with different chlorine substitution were also studied to evaluate the influence of molecular structure on the degradation process in the Cu(2+)/H2O2 system. Fourteen structure-related parameters were calculated using Gaussian 09 program. A quantitative structure-activity relationship (QSAR) model was established using SPSS software with measured rate constant (k) as dependent variable and calculated molecular descriptors as independent variables. A three-parameter model including energy of HOMO (E homo), molar heat capacity at constant volume (Cv(θ)), and the most positive net charge of hydrogen atoms (qH(+)) was selected for k prediction, with correlation coefficient R(2) = 0.878. Analyses of the model demonstrated that the Cv(θ) was the most significant factor affecting the k of chlorophenols. Variance analysis and standard t-value test were used to validate the model.

  13. Oxidation of disinfectants with Cl-substituted structure by a Fenton-like system Cu(2+)/H2O2 and analysis on their structure-reactivity relationship.

    PubMed

    Peng, Jianbiao; Li, Jianhua; Shi, Huanhuan; Wang, Zunyao; Gao, Shixiang

    2016-01-01

    As widely used chemicals intended to protect human being from infection of microorganisms, disinfectants are ubiquitous in the environment. Among them chlorine-substituted phenol is a basic structure in many disinfectant molecules. Removal of these pollutants from wastewater is of great concern. The oxidative degradation of antimicrobial agents such as triclosan, chlorofene, and dichlorofene by a Fenton-like system Cu(2+)/H2O2 was examined. Reaction conditions such as temperature, initial concentrations of H2O2 and Cu(2+), and pH were optimized using triclosan as a representative. The degradation kinetics of the above disinfectants followed pseudo-first-order kinetics under the investigated conditions. Fourteen chlorophenols (CPs) with different chlorine substitution were also studied to evaluate the influence of molecular structure on the degradation process in the Cu(2+)/H2O2 system. Fourteen structure-related parameters were calculated using Gaussian 09 program. A quantitative structure-activity relationship (QSAR) model was established using SPSS software with measured rate constant (k) as dependent variable and calculated molecular descriptors as independent variables. A three-parameter model including energy of HOMO (E homo), molar heat capacity at constant volume (Cv(θ)), and the most positive net charge of hydrogen atoms (qH(+)) was selected for k prediction, with correlation coefficient R(2) = 0.878. Analyses of the model demonstrated that the Cv(θ) was the most significant factor affecting the k of chlorophenols. Variance analysis and standard t-value test were used to validate the model. PMID:26408114

  14. Antimicrobial Resources for Disinfection of Potable Water Systems for Future Spacecraft

    NASA Technical Reports Server (NTRS)

    Morford, Megan A.; Birmele, Michele; Roberts, Michael S.

    2012-01-01

    As human exploration adventures beyond low earth orbit, life support systems will require more innovation and research to become self-sustaining and durable. One major concern about future space travel is the ability to store and decontaminate water for consumption and hygiene. This project explores materials and technologies for possible use in future water systems without requiring point-of-use (POU) filtering or chemical additives such as iodine or silver that require multiple doses to remain effective. This experimentation tested the efficacy of a variety of antimicrobial materials against biofilm formation in a high shear CDC Biofilm Reactor (CBR) and some materials in a low shear Drip Flow Reactor (DFR) which(also utilizes ultra violet light emitting diodes (UVLEDs) as an antimicrobial resource. Most materials were tested in the CBR using the ASTM E 2562-07 1method involving the Pseudomonas aeruginosa and coupon samples that vary in their antimicrobial coatings and surface layer topographies. In a controlled environmental chamber (CEC), the CBR underwent a batch phase, continuous flow phase (CFP), and a harvest before analysis. The DFR portion of this experimentation was performed in order to assess the antimicrobial capabilities of ultraviolet-A LEDs (UV-A) in potable water systems. The ASTM E 2647-08 was modified in order to incorporate UV-A LEDs and to operate as a closed, re-circulating system. The modified DFR apparatus that was utilized contains 4 separate channels each of which contain 2 UV-A LEDs (1 chamber is masked off to serve as a control) and each channel is equipped with its own reservoir and peristaltic pump head. The 10 DFR runs discussed in this report include 4 initial experimental runs that contained blank microscope slides to test the UVA LEDs alone, 2 that incorporated solid silver coupons, 2 that utilized titanium dioxide (Ti02) coupons as a photocatalyst, and 2 runs that utilized silver coated acrylic slides. Both the CBR and DFR

  15. Operating systems in the air transportation environment.

    NASA Technical Reports Server (NTRS)

    Cherry, G. W.

    1971-01-01

    Consideration of the problems facing air transport at present, and to be expected in the future. In the Northeast Corridor these problems involve community acceptance, airway and airport congestion and delays, passenger acceptance, noise reduction, and improvements in low-density short-haul economics. In the development of a superior short-haul operating system, terminal-configured vs cruise-configured vehicles are evaluated. CTOL, STOL, and VTOL aircraft of various types are discussed. In the field of noise abatement, it is shown that flight procedural techniques are capable of supplementing ?quiet engine' technology.

  16. The promise of air cargo: System aspects and vehicle design

    NASA Technical Reports Server (NTRS)

    Whitehead, A. H., Jr.

    1976-01-01

    The current operation of the air cargo system is reviewed. An assessment of the future of air cargo is provided by: (1) analyzing statistics and trends, (2) by noting system problems and inefficiencies, (3) by analyzing characteristics of 'air eligible' commodities, and (4) by showing the promise of new technology for future cargo aircraft with significant improvements in costs and efficiency. The following topics are discussed: (1) air cargo demand forecasts; (2) economics of air cargo transport; (3) the integrated air cargo system; (4) evolution of airfreighter design; and (5) the span distributed load concept.

  17. Design and bidding of UV disinfection equipment -- Case study

    SciTech Connect

    Akyurek, M.

    1998-07-01

    Ultraviolet (UV) disinfection systems are being widely considered for application to treated wastewaters, in lieu of conventional chlorination facilities. The number of UV systems operating in the US was approximately 50 in 1984. In 1990 there were over 500 systems, a ten-fold increase. The use of UV disinfection has increased since 1990, and will likely to increase in the future. It is anticipated that as many chlorine disinfection facilities reach their useful life, most of them will be replaced with UV disinfection systems. Several manufacturers offer different UV disinfection equipment. Each offers something different for the designer. There are also different approaches used in estimating the number of lamps needed for the disinfection system. The lack of standardization in determination of the number of lamps for a UV system poses problems for the designer. Such was the case during the design of the disinfection system for the Watertown, SD Wastewater Treatment Plant (WWRP). The purpose of this paper is to present a case study for the design and bidding of UV disinfection equipment.

  18. Air conditioning system and component therefore distributing air flow from opposite directions

    NASA Technical Reports Server (NTRS)

    Obler, H. D.; Bauer, H. B. (Inventor)

    1974-01-01

    The air conditioning system comprises a plurality of separate air conditioning units coupled to a common supply duct such that air may be introduced into the supply duct in two opposite flow directions. A plurality of outlets such as registers or auxiliary or branch ducts communicate with the supply duct and valve means are disposed in the supply duct at at least some of the outlets for automatically channelling a controllable amount of air from the supply duct to the associated outlet regardless of the direction of air flow within the supply duct. The valve means comprises an automatic air volume control apparatus for distribution within the air supply duct into which air may be introduced from two opposite directions. The apparatus incorporates a freely swinging movable vane in the supply duct to automatically channel into the associated outlet only the deflected air flow which has the higher relative pressure.

  19. One man electrochemical air revitalization system

    NASA Technical Reports Server (NTRS)

    Huddleston, J. C.; Aylward, J. R.

    1975-01-01

    An integrated water vapor electrolysis (WVE) hydrogen depolarized CO2 concentrator (HDC) system sized for one man support over a wide range of inlet air conditions was designed, fabricated, and tested. Data obtained during 110 days of testing verified that this system can provide the necessary oxygen, CO2 removal, and partial humidity control to support one man (without exceeding a cabin partial pressure of 3.0 mmHg for CO2 and while maintaining a 20% oxygen level), when operated at a WVE current of 50 amperes and an HDC current of 18 amperes. An evaluation to determine the physical properties of tetramethylammonium bicarbonate (TMAC) and hydroxide was made. This provides the necessary electrolyte information for designing an HDC cell using TMAC.

  20. 46 CFR 197.310 - Air compressor system.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Air compressor system. 197.310 Section 197.310 Shipping... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.310 Air compressor system. A compressor used to supply breathing air to a diver must have— (a) A volume tank that is— (1) Built and stamped...

  1. 46 CFR 197.310 - Air compressor system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Air compressor system. 197.310 Section 197.310 Shipping... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.310 Air compressor system. A compressor used to supply breathing air to a diver must have— (a) A volume tank that is— (1) Built and stamped...

  2. Efficiency of water disinfectants against Legionella pneumophila and Acanthamoeba.

    PubMed

    Dupuy, Mathieu; Mazoua, Stéphane; Berne, Florence; Bodet, Charles; Garrec, Nathalie; Herbelin, Pascaline; Ménard-Szczebara, Florence; Oberti, Sandrine; Rodier, Marie-Hélène; Soreau, Sylvie; Wallet, France; Héchard, Yann

    2011-01-01

    Free-living amoebae might be pathogenic by themselves and be a reservoir for bacterial pathogens, such as Legionella pneumophila. Not only could amoebae protect intra-cellular Legionella but Legionella grown within amoebae could undergo physiological modifications and become more resistant and more virulent. Therefore, it is important to study the efficiency of treatments on amoebae and Legionella grown within these amoebae to improve their application and to limit their impact on the environment. With this aim, we compared various water disinfectants against trophozoites of three Acanthamoeba strains and L. pneumophila alone or in co-culture. Three oxidizing disinfectants (chlorine, monochloramine, and chlorine dioxide) were assessed. All the samples were treated with disinfectants for 1 h and the disinfectant concentration was followed to calculate disinfectant exposure (Ct). We noticed that there were significant differences of susceptibility among the Acanthamoeba strains. However no difference was observed between infected and non-infected amoebae. Also, the comparison between the three disinfectants indicates that monochloramine was efficient at the same level towards free or co-cultured L. pneumophila while chlorine and chlorine dioxide were less efficient on co-cultured L. pneumophila. It suggests that these disinfectants should have different modes of action. Finally, our results provide for the first time disinfectant exposure values for Acanthamoeba treatments that might be used as references for disinfection of water systems.

  3. HVAC system performance and indoor air quality

    SciTech Connect

    Newman, J.L. )

    1991-01-01

    This paper reports that in the mid-seventies, the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) promulgated ASHRAE Standard 90-75 Energy Conservation in New Building Design, which called for revised minimum ventilation rates and the elimination of energy-wasting HVAC systems. Most building codes which cover energy conservation in the late seventies and eighties referred to this standard. This lowering of ventilation rates, coupled with the tighter building envelope (walls, windows, doors and roof) led to a reduction in outside air, both by engineering design and by minimizing infiltration through the structure. The minimum ventilation rates are based on the assumption that average concentrations of tobacco smoke exist in all enclosed spaces (30 percent of the population being smokers at two cigarettes per hour), rather than having separate rates for smoking and nonsmoking areas, as in the 1981 revision of the Standard. If tobacco smoke is ever declared a carcinogen, it will undoubtedly prompt a review of Standard 62-1989, as well as hasten totally smoke-free buildings.

  4. Disinfection By-Products: Formation and Occurrence in Drinking Water

    EPA Science Inventory

    The disinfection of drinking water has been rightly hailed as a public health triumph of the twentieth century. Millions of people worldwide receive quality drinking water every day from their public water systems. However, chemical disinfection has also produced an unintended he...

  5. The Next Generation of Disinfection By-Products

    EPA Science Inventory

    The disinfection of drinking water has been rightly hailed as a public health triumph of the 20th century. Millions of people worldwide receive quality drinking water every day from their public water systems. However, chemical disinfection has also produced an unintended health ...

  6. 40 CFR 141.172 - Disinfection profiling and benchmarking.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Disinfection profiling and benchmarking. 141.172 Section 141.172 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED..., 2000. As a minimum, the system with a single point of disinfectant application prior to entrance to...

  7. 40 CFR 141.172 - Disinfection profiling and benchmarking.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Disinfection profiling and benchmarking. 141.172 Section 141.172 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED..., 2000. As a minimum, the system with a single point of disinfectant application prior to entrance to...

  8. 40 CFR 141.172 - Disinfection profiling and benchmarking.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Disinfection profiling and benchmarking. 141.172 Section 141.172 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED..., 2000. As a minimum, the system with a single point of disinfectant application prior to entrance to...

  9. 40 CFR 141.172 - Disinfection profiling and benchmarking.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Disinfection profiling and benchmarking. 141.172 Section 141.172 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED..., 2000. As a minimum, the system with a single point of disinfectant application prior to entrance to...

  10. 40 CFR 141.172 - Disinfection profiling and benchmarking.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Disinfection profiling and benchmarking. 141.172 Section 141.172 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED..., 2000. As a minimum, the system with a single point of disinfectant application prior to entrance to...

  11. The Next Generation of Drinking Water Disinfection By-Products

    EPA Science Inventory

    The disinfection of drinking water has been rightly hailed as a public health triumph of the 20th century. Millions of people worldwide receive quality drinking water every day from their public water systems. However, chemical disinfection has also produced an unintended healt...

  12. Guidelines for ultraviolet disinfection of drinking water: considerations for Ontario.

    PubMed

    Hofmann, Ron; Andrews, Bob; Lachmaniuk, Pat

    The Ontario Ministry of the Environment is actively investigating protocols for approving the installation of ultraviolet (UV) disinfection systems for drinking water disinfection. This paper discusses issues that may be considered for selecting the appropriate UV dose, validating UV reactor performance, and monitoring the performance of the reactor once installed.

  13. Biofilm and siderophore effects on secondary waste water disinfection.

    PubMed

    Saidi, N; Kouki, S; Mehri, I; Ben Rejeb, A; Belila, A; Hassen, A; Ouzari, H

    2011-10-01

    The efficiency of ultraviolet (UV) light disinfection of wastewater effluent using a large-scale pilot system was studied. The relationship between biofilm and siderophore production and UV doses received by Pseudomonas aeruginosa strain ATCC 15442 was determined. UV decreased pyoverdine production and enhanced biofilm production. Consequently external factors conditioned by both pyoverdine and biofilm may affect the UV effect on bacterial disinfection.

  14. Evaluation of disinfectants to prevent mechanical transmission of viruses and a viroid in greenhouse tomato production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In an effort to select disinfectant(s) with capability to deactivate infectivity from a broad range of viruses and viroids that are commonly observed in greenhouse tomato production systems, a total of 16 disinfectants were evaluated against Pepino mosaic virus (PepMV), Tomato mosaic virus (ToMV), T...

  15. Heating, ventilation and air conditioning systems

    SciTech Connect

    Kyle, D.M.; Sullivan, R.A.

    1993-02-01

    A study is made of several outstanding issues concerning the commercial development of environmental control systems for electric vehicles (EVs). Engineering design constraints such as federal regulations and consumer requirements are first identified. Next, heating and cooling loads in a sample automobile are calculated using a computer model available from the literature. The heating and cooling loads are then used as a basis for estimating the electrical consumption that is to be expected for heat pumps installed in EVs. The heat pump performance is evaluated using an automobile heat pump computer model which has been developed recently at Oak Ridge National Laboratory (ORNL). The heat pump design used as input to the model consists of typical finned-tube heat exchangers and a hermetic compressor driven by a variable-speed brushless dc motor. The simulations suggest that to attain reasonable system efficiencies, the interior heat exchangers that are currently installed as automobile air conditioning will need to be enlarged. Regarding the thermal envelope of the automobile itself, calculations are made which show that considerable energy savings will result if steps are taken to reduce {open_quote}hot soak{close_quote} temperatures and if the outdoor air ventilation rate is well controlled. When these changes are made, heating and cooling should consume less than 10% of the total stored electrical energy for steady driving in most U.S. climates. However, this result depends strongly upon the type of driving: The fraction of total power for heating and cooling ({open_quote}range penalty{close_quote}) increases sharply for driving scenarios having low average propulsion power, such as stop-and-go driving.

  16. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  17. Chalkbrood transmission in the alfalfa leafcutting bee: the impact of disinfecting bee cocoons in loose cell management systems.

    PubMed

    James, R R

    2011-08-01

    Understanding pathogen transmission could illuminate new methods for disease prevention. A case in point is chalkbrood in the alfalfa leafcutting bee [Megachile rotundata (F.)]. Propagation of this solitary bee is severely hampered by chalkbrood, a larval disease caused by Ascosphaera aggregata (Ascomycota). Alfalfa leafcutting bees nest in existing cavities in wood or hollow reeds and overwinter as larvae. In the early summer, emerging adults frequently must chew through dead, diseased siblings that block their exit, becoming contaminated with chalkbrood spores in the process. When alfalfa leafcutting bees are used as a commercial pollinator, the cocoons are removed from nesting boards to reduce chalkbrood transmission, but the disease is still common. To determine if these removed cocoons (called loose cells) are an important source of disease transmission, they were disinfected with a fungicide before bees were incubated, and released in the field. Chalkbrood prevalence among the progeny of the treated bees was reduced up to 50% in one field trial, but not significantly when tested in an on-farm trial. Thus, substantial disease transmission still occurred when the loose cells were disinfected, and even when clean nesting materials were used. In conclusion, pathogen transmission must still be occurring from another source that has yet to be identified. Another possible source of transmission could arise from bees that emerge midsummer in populations with a high percent of multivoltinism, but dirty nesting boards and feral bees also may be minor sources of transmission. PMID:22251678

  18. Systems evaluation of low density air transportation concepts

    NASA Technical Reports Server (NTRS)

    Bruce, R. W.; Webb, H. M.

    1972-01-01

    Methods were studied for improving air transportation to low-density population regions in the U.S. through the application of new aeronautical technology. The low-density air service concepts are developed for selected regions, and critical technologies that presently limit the effective application of low-density air transportation systems are identified.

  19. Effective photocatalytic disinfection of E. coli K-12 using AgBr-Ag-Bi2WO6 nanojunction system irradiated by visible light: the role of diffusing hydroxyl radicals.

    PubMed

    Zhang, Li-Sha; Wong, Kin-Hang; Yip, Ho-Yin; Hu, Chun; Yu, Jimmy C; Chan, Chiu-Yeung; Wong, Po-Keung

    2010-02-15

    Urgent development of effective and low-cost disinfecting technologies is needed to address the problems caused by an outbreak of harmful microorganisms. In this work, we report an effective photocatalytic disinfection of E. coli K-12 by using a AgBr-Ag-Bi(2)WO(6) nanojunction system as a catalyst under visible light (lambda >or= 400 nm) irradiation. The visible-light-driven (VLD) AgBr-Ag-Bi(2)WO(6) nanojunction could completely inactivate 5 x 10(7) cfu mL(-1) E. coli K-12 within 15 min, which was superior to other VLD photocatalysts such as Bi(2)WO(6) superstructure, Ag-Bi(2)WO(6) and AgBr-Ag-TiO(2) composite. Moreover, the photochemical mechanism of bactericidal action for the AgBr-Ag-Bi(2)WO(6) nanojunction was investigated by using different scavengers. It was found that the diffusing hydroxyl radicals generated both by the oxidative pathway and the reductive pathway play an important role in the photocatalytic disinfection. Moreover, direct contact between the AgBr-Ag-Bi(2)WO(6) nanojunction and bacterial cells was not necessary for the photocatalytic disinfection of E. coli K-12. Finally, the photocatalytic destruction of the bacterial cells was directly observed by TEM images and further confirmed by the determination of potassium ion (K(+)) leakage from the killed bacteria. This work provides a potential effective VLD photocatalyst to disinfect the bacterial cells, even to destruct the biofilm that can provide shelter and substratum for microorganisms and resist to disinfection.

  20. Effective photocatalytic disinfection of E. coli K-12 using AgBr-Ag-Bi2WO6 nanojunction system irradiated by visible light: the role of diffusing hydroxyl radicals.

    PubMed

    Zhang, Li-Sha; Wong, Kin-Hang; Yip, Ho-Yin; Hu, Chun; Yu, Jimmy C; Chan, Chiu-Yeung; Wong, Po-Keung

    2010-02-15

    Urgent development of effective and low-cost disinfecting technologies is needed to address the problems caused by an outbreak of harmful microorganisms. In this work, we report an effective photocatalytic disinfection of E. coli K-12 by using a AgBr-Ag-Bi(2)WO(6) nanojunction system as a catalyst under visible light (lambda >or= 400 nm) irradiation. The visible-light-driven (VLD) AgBr-Ag-Bi(2)WO(6) nanojunction could completely inactivate 5 x 10(7) cfu mL(-1) E. coli K-12 within 15 min, which was superior to other VLD photocatalysts such as Bi(2)WO(6) superstructure, Ag-Bi(2)WO(6) and AgBr-Ag-TiO(2) composite. Moreover, the photochemical mechanism of bactericidal action for the AgBr-Ag-Bi(2)WO(6) nanojunction was investigated by using different scavengers. It was found that the diffusing hydroxyl radicals generated both by the oxidative pathway and the reductive pathway play an important role in the photocatalytic disinfection. Moreover, direct contact between the AgBr-Ag-Bi(2)WO(6) nanojunction and bacterial cells was not necessary for the photocatalytic disinfection of E. coli K-12. Finally, the photocatalytic destruction of the bacterial cells was directly observed by TEM images and further confirmed by the determination of potassium ion (K(+)) leakage from the killed bacteria. This work provides a potential effective VLD photocatalyst to disinfect the bacterial cells, even to destruct the biofilm that can provide shelter and substratum for microorganisms and resist to disinfection. PMID:20085257

  1. Closed-loop air cooling system for a turbine engine

    DOEpatents

    North, William Edward

    2000-01-01

    Method and apparatus are disclosed for providing a closed-loop air cooling system for a turbine engine. The method and apparatus provide for bleeding pressurized air from a gas turbine engine compressor for use in cooling the turbine components. The compressed air is cascaded through the various stages of the turbine. At each stage a portion of the compressed air is returned to the compressor where useful work is recovered.

  2. Compressed Air System Improvements at an Automotive Plant

    SciTech Connect

    2000-10-01

    In 1998, the Ford Motor Company implemented a compressed air system improvement project at its Woodhaven Stamping plant in Woodhaven, Michigan. As a result of the system approach that it took towards improving the plant's compressed air system, the plant was able to take an 800-hp air compressor offline, shut down several high pressure satellite compressors, and operate the remaining compressors more efficiently.

  3. 40 CFR 141.72 - Disinfection.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... serves water to the public. Water in the distribution system with a heterotrophic bacteria concentration... heterotrophic bacteria plate count (HPC) is measured; c=number of instances where the residual disinfectant... system with a heterotrophic bacteria concentration less than or equal to 500/ml, measured...

  4. 40 CFR 141.72 - Disinfection.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... serves water to the public. Water in the distribution system with a heterotrophic bacteria concentration... heterotrophic bacteria plate count (HPC) is measured; c=number of instances where the residual disinfectant... system with a heterotrophic bacteria concentration less than or equal to 500/ml, measured...

  5. Energy savings potential in air conditioners and chiller systems

    DOE PAGES

    Kaya, Durmus; Alidrisi, Hisham

    2014-01-22

    In the current paper we quantified and evaluated the energy saving potential in air conditioners and chiller systems. Here, we also showed how to reduce the cost of air conditioners and chiller systems in existing facilities on the basis of payback periods. Among the measures investigated were: (1) installing higher efficiency air conditioners, (2) installing higher efficiency chillers, (3) duty cycling air conditioning units, and (4) utilizing existing economizers on air conditioning units. For each method, examples were provided from Arizona, USA. In these examples, the amount of saved energy, the financial evaluation of this energy, and the investment costmore » and pay back periods were calculated.« less

  6. Energy savings potential in air conditioners and chiller systems

    SciTech Connect

    Kaya, Durmus; Alidrisi, Hisham

    2014-01-22

    In the current paper we quantified and evaluated the energy saving potential in air conditioners and chiller systems. Here, we also showed how to reduce the cost of air conditioners and chiller systems in existing facilities on the basis of payback periods. Among the measures investigated were: (1) installing higher efficiency air conditioners, (2) installing higher efficiency chillers, (3) duty cycling air conditioning units, and (4) utilizing existing economizers on air conditioning units. For each method, examples were provided from Arizona, USA. In these examples, the amount of saved energy, the financial evaluation of this energy, and the investment cost and pay back periods were calculated.

  7. Controlling Legionella in hospital drinking water: an evidence-based review of disinfection methods.

    PubMed

    Lin, Yusen E; Stout, Janet E; Yu, Victor L

    2011-02-01

    Hospital-acquired Legionnaires' disease is directly linked to the presence of Legionella in hospital drinking water. Disinfecting the drinking water system is an effective preventive measure. The efficacy of any disinfection measures should be validated in a stepwise fashion from laboratory assessment to a controlled multiple-hospital evaluation over a prolonged period of time. In this review, we evaluate systemic disinfection methods (copper-silver ionization, chlorine dioxide, monochloramine, ultraviolet light, and hyperchlorination), a focal disinfection method (point-of-use filtration), and short-term disinfection methods in outbreak situations (superheat-and-flush with or without hyperchlorination). The infection control practitioner should take the lead in selection of the disinfection system and the vendor. Formal appraisals by other hospitals with experience of the system under consideration is indicated. Routine performance of surveillance cultures of drinking water to detect Legionella and monitoring of disinfectant concentrations are necessary to ensure long-term efficacy.

  8. The air transportation/energy system

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The changing pattern of transportation is discussed, and the energy intensiveness of various modes of transportation is also analyzed. Sociopsychological data affecting why people travel by air are presented, along with governmental regulation and air transportation economics. The aviation user tax structure is shown in tabular form.

  9. Method of aeration disinfecting and drying grain in bulk and pretreating seeds and a transverse blow silo grain dryer therefor

    DOEpatents

    Danchenko, Vitaliy G.; Noyes, Ronald T.; Potapovych, Larysa P.

    2012-02-28

    Aeration drying and disinfecting grain crops in bulk and pretreating seeds includes passing through a bulk of grain crops and seeds disinfecting and drying agents including an ozone and air mixture and surrounding air, subdividing the disinfecting and drying agents into a plurality of streams spaced from one another in a vertical direction, and passing the streams at different heights through levels located at corresponding heights of the bulk of grain crops and seeds transversely in a substantially horizontal direction.

  10. PremAir{trademark} catalyst systems: A new approach to clean air

    SciTech Connect

    Poles, T.; Anderson, D.R.; Durilla, M.; Heck, R.; Hoke, J.; Ober, R.; Rudy, W.

    1996-12-01

    PremAir{trademark} catalyst systems represents a new approach to air pollution control--one that focuses on destroying pollutants already in the air. PremAir is the trademark for a family of developmental catalysts capable of reducing ozone, carbon monoxide and potentially other pollutants in ambient air that comes into contact with catalyst-coated surfaces. The more air that comes into contact with the surface the more pollutants that can be destroyed. For this reason, Engelhard has focused its attention on heat-exchange equipment such as automotive radiators and air-conditioner condensers. It is because of advances in catalysis achieved at Engelhard that PremAir catalysts are active at the low temperatures found in these environments. In Los Angeles, which has the country`s worst smog problem, approximately one trillion cubic feet per day of air pass through car radiators and five trillion cubic feet per day pass through air conditioners. Most of the research, development and testing work performed to date has been on ozone catalysts and their application to car radiators. This paper discusses that work and the potential benefits associated with the PremAir technology. In addition, preliminary work on stationary applications of this new technology is discussed.

  11. The microbiological quality of air improves when using air conditioning systems in cars

    PubMed Central

    2010-01-01

    Background Because of better comfort, air conditioning systems are a common feature in automobiles these days. However, its impact on the number of particles and microorganisms inside the vehicle - and by this its impact on the risk of an allergic reaction - is yet unknown. Methods Over a time period of 30 months, the quality of air was investigated in three different types of cars (VW Passat, VW Polo FSI, Seat Alhambra) that were all equipped with a automatic air conditioning system. Operation modes using fresh air from outside the car as well as circulating air from inside the car were examined. The total number of microorganisms and the number of mold spores were measured by impaction in a high flow air sampler. Particles of 0.5 to 5.0 μm diameter were counted by a laser particle counter device. Results Overall 32 occasions of sampling were performed. The concentration of microorganisms outside the cars was always higher than it was inside the cars. Few minutes after starting the air conditioning system the total number of microorganisms was reduced by 81.7%, the number of mold spores was reduced by 83.3%, and the number of particles was reduced by 87.8%. There were no significant differences neither between the types of cars nor between the types of operation mode of the air conditioning system (fresh air vs. circulating air). All parameters that were looked for in this study improved during utilization of the car's air conditioning system. Conclusions We believe that the risk of an allergic reaction will be reduced during use also. Nevertheless, we recommend regular maintenance of the system and replacement of older filters after defined changing intervals. PMID:20515449

  12. Impact of disinfection on drinking water biofilm bacterial community.

    PubMed

    Mi, Zilong; Dai, Yu; Xie, Shuguang; Chen, Chao; Zhang, Xiaojian

    2015-11-01

    Disinfectants are commonly applied to control the growth of microorganisms in drinking water distribution systems. However, the effect of disinfection on drinking water microbial community remains poorly understood. The present study investigated the impacts of different disinfectants (chlorine and chloramine) and dosages on biofilm bacterial community in bench-scale pipe section reactors. Illumina MiSeq sequencing illustrated that disinfection strategy could affect both bacterial diversity and community structure of drinking water biofilm. Proteobacteria tended to predominate in chloraminated drinking water biofilms, while Firmicutes in chlorinated and unchlorinated biofilms. The major proteobacterial groups were influenced by both disinfectant type and dosage. In addition, chloramination had a more profound impact on bacterial community than chlorination.

  13. UV disinfection pilot plant study at the Savannah River Site

    SciTech Connect

    Huffines, R.L.; Beavers, B.A.

    1993-01-01

    An ultraviolet light disinfection system pilot plant was operated at the Savannah River Site Central Shops sanitary wastewater treatment package plant July 14, 1992 through August 13, 1992. The purpose was to determine the effectiveness of ultraviolet light disinfection on the effluent from the small package-type wastewater treatment plants currently used on-site. This pilot plant consisted of a rack of UV lights suspended in a stainless steel channel through which a sidestream of effluent from the treatment plant clarifier was pumped. Fecal coliform analyses were performed on the influent to and effluent from the pilot unit to verify the disinfection process. UV disinfection was highly effective in reducing fecal coliform colonies within NPDES permit limitations even under process upset conditions. The average fecal coliform reduction exceeded 99.7% using ultraviolet light disinfection under normal operating conditions at the package treatment plants.

  14. UV disinfection pilot plant study at the Savannah River Site

    SciTech Connect

    Huffines, R.L.; Beavers, B.A.

    1993-05-01

    An ultraviolet light disinfection system pilot plant was operated at the Savannah River Site Central Shops sanitary wastewater treatment package plant July 14, 1992 through August 13, 1992. The purpose was to determine the effectiveness of ultraviolet light disinfection on the effluent from the small package-type wastewater treatment plants currently used on-site. This pilot plant consisted of a rack of UV lights suspended in a stainless steel channel through which a sidestream of effluent from the treatment plant clarifier was pumped. Fecal coliform analyses were performed on the influent to and effluent from the pilot unit to verify the disinfection process. UV disinfection was highly effective in reducing fecal coliform colonies within NPDES permit limitations even under process upset conditions. The average fecal coliform reduction exceeded 99.7% using ultraviolet light disinfection under normal operating conditions at the package treatment plants.

  15. Impact of disinfection on drinking water biofilm bacterial community.

    PubMed

    Mi, Zilong; Dai, Yu; Xie, Shuguang; Chen, Chao; Zhang, Xiaojian

    2015-11-01

    Disinfectants are commonly applied to control the growth of microorganisms in drinking water distribution systems. However, the effect of disinfection on drinking water microbial community remains poorly understood. The present study investigated the impacts of different disinfectants (chlorine and chloramine) and dosages on biofilm bacterial community in bench-scale pipe section reactors. Illumina MiSeq sequencing illustrated that disinfection strategy could affect both bacterial diversity and community structure of drinking water biofilm. Proteobacteria tended to predominate in chloraminated drinking water biofilms, while Firmicutes in chlorinated and unchlorinated biofilms. The major proteobacterial groups were influenced by both disinfectant type and dosage. In addition, chloramination had a more profound impact on bacterial community than chlorination. PMID:26574105

  16. GOSAT Air Pollution Watch - Rapid Response System for Local Air Pollution

    NASA Astrophysics Data System (ADS)

    Matsunaga, T.; Sawada, Y.; Kamei, A.; Uchiyama, A.

    2015-12-01

    GOSAT (Greenhouse Gases Observing Satellite) launched in 2009 and its successor, GOSAT-2, to be launched in FY 2017, have push-broom imaging systems with more than one UV band with higher spatial resolution than OMI, MODIS, and VIIRS. Such imaging systems are useful for mapping the spatial extent of the optically thick air mass with particulate matters. GOSAT Air Pollution Watch, a rapid response system mainly using GOSAT CAI (Cloud and Aerosol Imager) data for local air pollution issues is being developed in NIES (National Institute for Environmental Studies) GOSAT-2 Project. The current design of GOSAT Air Pollution Watch has three data processing steps as follows: Step 1) Making a cloud mask Step 2) Estimating AOT (Aerosol Optical Thickness) in the UV region (380 nm for CAI) Step 3) Converting AOT to atmospheric pollution parameters such as PM2.5 concentration Data processing algorithms in GOSAT Air Pollution Watch are based on GOSAT/GOSAT-2 algorithms for aerosol product generation with some modification for faster and timely data processing. Data from GOSAT Air Pollution Watch will be used to inform the general public the current distribution of the polluted air. In addition, they will contribute to short term prediction of the spatial extent of the polluted air using atmospheric transport models. In this presentation, the background, the current status, and the future prospect of GOSAT Air Pollution Watch will be reported together with the development status of GOSAT-2.

  17. Natural Air Purifier

    NASA Technical Reports Server (NTRS)

    1993-01-01

    NASA environmental research has led to a plant-based air filtering system. Dr. B.C. Wolverton, a former NASA engineer who developed a biological filtering system for space life support, served as a consultant to Terra Firma Environmental. The company is marketing the BioFilter, a natural air purifier that combines activated carbon and other filter media with living plants and microorganisms. The filter material traps and holds indoor pollutants; plant roots and microorganisms then convert the pollutants into food for the plant. Most non-flowering house plants will work. After pollutants have been removed, the cleansed air is returned to the room through slits in the planter. Terra Firma is currently developing a filter that will also disinfect the air.

  18. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    SciTech Connect

    Rudd, Armin; Bergey, Daniel

    2014-02-01

    In this project, Building America research team Building Science Corporation tested the effectiveness of ventilation systems at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. This was because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four system factor categories: balance, distribution, outside air source, and recirculation filtration. Recommended system factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.

  19. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    SciTech Connect

    Rudd, A.; Bergey, D.

    2014-02-01

    Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. It was inferior because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.

  20. Recent advances in drinking water disinfection: successes and challenges.

    PubMed

    Ngwenya, Nonhlanhla; Ncube, Esper J; Parsons, James

    2013-01-01

    Drinking water is the most important single source of human exposure to gastroenteric diseases, mainly as a result of the ingestion of microbial contaminated water. Waterborne microbial agents that pose a health risk to humans include enteropathogenic bacteria, viruses, and protozoa. Therefore, properly assessing whether these hazardous agents enter drinking water supplies, and if they do, whether they are disinfected adequately, are undoubtedly aspects critical to protecting public health. As new pathogens emerge, monitoring for relevant indicator microorganisms (e.g., process microbial indicators, fecal indicators, and index and model organisms) is crucial to ensuring drinking water safety. Another crucially important step to maintaining public health is implementing Water Safety Plans (WSPs), as is recommended by the current WHO Guidelines for Drinking Water Quality. Good WSPs include creating health-based targets that aim to reduce microbial risks and adverse health effects to which a population is exposed through drinking water. The use of disinfectants to inactivate microbial pathogens in drinking water has played a central role in reducing the incidence of waterborne diseases and is considered to be among the most successful interventions for preserving and promoting public health. Chlorine-based disinfectants are the most commonly used disinfectants and are cheap and easy to use. Free chlorine is an effective disinfectant for bacteria and viruses; however, it is not always effective against C. parvum and G. lamblia. Another limitation of using chlorination is that it produces disinfection by-products (DBPs), which pose potential health risks of their own. Currently, most drinking water regulations aggressively address DBP problems in public water distribution systems. The DBPs of most concern include the trihalomethanes (THMs), the haloacetic acids (HAAs), bromate, and chlorite. However, in the latest edition of the WHO Guidelines for Drinking Water Quality

  1. Recent advances in drinking water disinfection: successes and challenges.

    PubMed

    Ngwenya, Nonhlanhla; Ncube, Esper J; Parsons, James

    2013-01-01

    Drinking water is the most important single source of human exposure to gastroenteric diseases, mainly as a result of the ingestion of microbial contaminated water. Waterborne microbial agents that pose a health risk to humans include enteropathogenic bacteria, viruses, and protozoa. Therefore, properly assessing whether these hazardous agents enter drinking water supplies, and if they do, whether they are disinfected adequately, are undoubtedly aspects critical to protecting public health. As new pathogens emerge, monitoring for relevant indicator microorganisms (e.g., process microbial indicators, fecal indicators, and index and model organisms) is crucial to ensuring drinking water safety. Another crucially important step to maintaining public health is implementing Water Safety Plans (WSPs), as is recommended by the current WHO Guidelines for Drinking Water Quality. Good WSPs include creating health-based targets that aim to reduce microbial risks and adverse health effects to which a population is exposed through drinking water. The use of disinfectants to inactivate microbial pathogens in drinking water has played a central role in reducing the incidence of waterborne diseases and is considered to be among the most successful interventions for preserving and promoting public health. Chlorine-based disinfectants are the most commonly used disinfectants and are cheap and easy to use. Free chlorine is an effective disinfectant for bacteria and viruses; however, it is not always effective against C. parvum and G. lamblia. Another limitation of using chlorination is that it produces disinfection by-products (DBPs), which pose potential health risks of their own. Currently, most drinking water regulations aggressively address DBP problems in public water distribution systems. The DBPs of most concern include the trihalomethanes (THMs), the haloacetic acids (HAAs), bromate, and chlorite. However, in the latest edition of the WHO Guidelines for Drinking Water Quality

  2. Optical air data systems and methods

    NASA Technical Reports Server (NTRS)

    Caldwell, Loren M. (Inventor); Tang, Shoou-Yu (Inventor); O'Brien, Martin J. (Inventor)

    2011-01-01

    A method for remotely sensing air outside a moving aircraft includes generating laser radiation within a swept frequency range. A portion of the laser radiation is projected from the aircraft into the air to induce scattered laser radiation. Filtered scattered laser radiation, filtered laser radiation, and unfiltered laser radiation are detected. At least one actual ratio is determined from data corresponding to the filtered scattered laser radiation and the unfiltered laser radiation. One or more air parameters are determined by correlating the actual ratio to at least one reference ratio.

  3. Optical air data systems and methods

    NASA Technical Reports Server (NTRS)

    Caldwell, Loren M. (Inventor); Tang, Shoou-Yu (Inventor); O'Brien, Martin J. (Inventor)

    2009-01-01

    A method for remotely sensing air outside a moving aircraft includes generating laser radiation within a swept frequency range. A portion of the laser radiation is projected from the aircraft into the air to induce scattered laser radiation. Filtered scattered laser radiation, filtered laser radiation, and unfiltered laser radiation are detected. At least one actual ratio is determined from data corresponding to the filtered scattered laser radiation and the unfiltered laser radiation. One or more air parameters are determined by correlating the actual ratio to at least one reference ratio.

  4. Air conditioning system with supplemental ice storing and cooling capacity

    DOEpatents

    Weng, Kuo-Lianq; Weng, Kuo-Liang

    1998-01-01

    The present air conditioning system with ice storing and cooling capacity can generate and store ice in its pipe assembly or in an ice storage tank particularly equipped for the system, depending on the type of the air conditioning system. The system is characterized in particular in that ice can be produced and stored in the air conditioning system whereby the time of supplying cooled air can be effectively extended with the merit that the operation cycle of the on and off of the compressor can be prolonged, extending the operation lifespan of the compressor in one aspect. In another aspect, ice production and storage in great amount can be performed in an off-peak period of the electrical power consumption and the stored ice can be utilized in the peak period of the power consumption so as to provide supplemental cooling capacity for the compressor of the air conditioning system whereby the shift of peak and off-peak power consumption can be effected with ease. The present air conditioning system can lower the installation expense for an ice-storing air conditioning system and can also be applied to an old conventional air conditioning system.

  5. The effectiveness of photocatalytic ionisation disinfection of filter materials.

    PubMed

    Pietrzak, Katarzyna; Gutarowska, Beata

    2013-01-01

    The purpose of this study was to determine the effectiveness of photocatalytic ionisation as a disinfection method for filter materials contaminated by microorganisms, and to assess how air relative humidity (RH), time and microbe type influence the effectiveness of this disinfection. In the quantitative analysis of a used car air filter, bacterial contamination equalled 1.2 x 10(5) cfu/cm2, fungal contamination was 3.8 x 10(6) cfu/cm2, and the isolated microorganisms were Aspergillus niger, Bacillus megaterium, Cladosporium herbarum, Cryptococcus laurenti, Micrococcus sp., Rhodotorula glutinis and Staphylococcus cohnii. In the model experiment, three isolates (C. herbarum, R. glutinis, S. cohnii) and 3 ATCC species (A. niger, E. coli, S. aureus) were used for photocatalytic ionisation disinfection. The conditions of effective photocatalytic ionisation disinfection (R > or = 99.9%) were established as 2-3 h at RH = 77% (bacteria) and 6-24 h at RH = 53% (fungi). RH has an influence on the effectiveness of the photocatalytic disinfection process; the highest effectiveness was obtained for bacteria at RH = 77%, with results 5% higher than for RH = 49%. The studies show that the sensitivity of microorganisms to photocatalytic ionisation disinfection is ordered as follows: Gram-positive bacteria (S. cohnii, S. aureus), Gram-negative bacteria (E. coli), yeasts (R. glutinis), and moulds (C. herbarum, A. niger). Of all the mathematical models used for the description of death dynamics after photocatalytic ionisation disinfection, the Chick-Watson model is the most useful, but for more resistant microorganisms, the delayed Chick-Watson model is highly recommended. It therefore seems, that the presented disinfection method of photocatalytic ionisation can be successfully used to clean filtration materials.

  6. CHLORINE DISINFECTION OF AEROMONAS

    EPA Science Inventory

    The bacterial genus Aeromonas is currently listed on the USEPA's Candidate Contaminant List (CCL). Resistance to chemical disinfection is an essential aspect regarding all microbial groups listed on the CCL. This study was designed to determine the inactivation kinetics of Aeromo...

  7. Air pollution and the respiratory system.

    PubMed

    Arbex, Marcos Abdo; Santos, Ubiratan de Paula; Martins, Lourdes Conceição; Saldiva, Paulo Hilário Nascimento; Pereira, Luiz Alberto Amador; Braga, Alfésio Luis Ferreira

    2012-01-01

    Over the past 250 years-since the Industrial Revolution accelerated the process of pollutant emission, which, until then, had been limited to the domestic use of fuels (mineral and vegetal) and intermittent volcanic emissions-air pollution has been present in various scenarios. Today, approximately 50% of the people in the world live in cities and urban areas and are exposed to progressively higher levels of air pollutants. This is a non-systematic review on the different types and sources of air pollutants, as well as on the respiratory effects attributed to exposure to such contaminants. Aggravation of the symptoms of disease, together with increases in the demand for emergency treatment, the number of hospitalizations, and the number of deaths, can be attributed to particulate and gaseous pollutants, emitted by various sources. Chronic exposure to air pollutants not only causes decompensation of pre-existing diseases but also increases the number of new cases of asthma, COPD, and lung cancer, even in rural areas. Air pollutants now rival tobacco smoke as the leading risk factor for these diseases. We hope that we can impress upon pulmonologists and clinicians the relevance of investigating exposure to air pollutants and of recognizing this as a risk factor that should be taken into account in the adoption of best practices for the control of the acute decompensation of respiratory diseases and for maintenance treatment between exacerbations.

  8. 46 CFR 197.310 - Air compressor system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Air compressor system. 197.310 Section 197.310 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE OCCUPATIONAL SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.310 Air compressor system. A...

  9. Thermal Environment for Classrooms. Central System Approach to Air Conditioning.

    ERIC Educational Resources Information Center

    Triechler, Walter W.

    This speech compares the air conditioning requirements of high-rise office buildings with those of large centralized school complexes. A description of one particular air conditioning system provides information about the system's arrangement, functions, performance efficiency, and cost effectiveness. (MLF)

  10. 14 CFR 33.66 - Bleed air system.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Bleed air system. 33.66 Section 33.66 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.66 Bleed air system....

  11. 14 CFR 33.66 - Bleed air system.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Bleed air system. 33.66 Section 33.66 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.66 Bleed air system....

  12. 14 CFR 33.66 - Bleed air system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Bleed air system. 33.66 Section 33.66 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.66 Bleed air system....

  13. 14 CFR 33.66 - Bleed air system.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Bleed air system. 33.66 Section 33.66 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.66 Bleed air system....

  14. EMISSIONS PROCESSING FOR THE ETA/ CMAQ AIR QUALITY FORECAST SYSTEM

    EPA Science Inventory

    NOAA and EPA have created an Air Quality Forecast (AQF) system. This AQF system links an adaptation of the EPA's Community Multiscale Air Quality Model with the 12 kilometer ETA model running operationally at NOAA's National Center for Environmental Predication (NCEP). One of the...

  15. Secondary air control system in an internal combustion engine

    SciTech Connect

    Takeda, K.

    1981-11-10

    This application discloses a secondary air control system in an internal combustion engine. The system comprises: an exhaust gas purifying device mounted on an exhaust pipe; a secondary air control valve which comprises a diaphragm actuated by vacuum pressure for controlling secondary supply air to said exhaust gas purifying device; a solenoid valve for controlling said vacuum pressure which acts upon said secondary air control valve; a vacuum sensor which detects the vacuum pressure at a small venturi of a carburetor; a thermo-sensor for detecting the intake air temperature; an air flow meter mounted on a secondary air supply pipe; a thermo-sensor for detecting the secondary air temperature mounted on said secondary air supply pipe, and; a computer to which said valuum sensor, said thermo-sensors, and said air flow meter are connected so as to feed input signals thereto, said solenoid valve being connected to the output of said computer so as to control the secondary air quantity in response to said input signals.

  16. An insight of disinfection by-product (DBP) formation by alternative disinfectants for swimming pool disinfection under tropical conditions.

    PubMed

    Yang, Linyan; Schmalz, Christina; Zhou, Jin; Zwiener, Christian; Chang, Victor W-C; Ge, Liya; Wan, Man Pun

    2016-09-15

    Sodium hypochlorite (NaClO) is the most commonly used disinfectant in pool treatment system. Outdoor pools usually suffer from the strong sunlight irradiation which degrades the free chlorine rapidly. In addition, more pools start to adopt the recirculation of swimming pool water, which intensifies the disinfection by-product (DBP) accumulation issue. Given these potential drawbacks of using NaClO in the tropical environment, two alternative organic-based disinfectants, trichloroisocyanuric acid (TCCA, C3Cl3N3O3) and bromochlorodimethylhydantoin (BCDMH, C5H6BrClN2O2), were investigated and compared to NaClO in terms of their self-degradation and the formation of DBPs, including trihalomethanes (THMs) and haloacetic acids (HAAs), under simulated tropical climate conditions. The result reveals that halogen stabilizer, TCCA, had the advantages of slower free chlorine degradation and lower DBP concentration compared to NaClO, which makes it a good alternative disinfectant. BCDMH was not recommended mainly due to the highly reactive disinfecting ingredient, hypobromous acid (HBrO), which fails to sustain the continuous disinfection requirement. Total disinfectant dosage was the main factor that affects residual chlorine/bromine and THM/HAA formation regardless of different disinfectant dosing methods, e.g. shock dosing (one-time spiking) in the beginning, and continuous dosing during the whole experimental period. Two-stage second-order-kinetic-based models demonstrate a good correlation between the measured and predicted data for chlorine decay (R(2) ≥ 0.95), THM (R(2) ≥ 0.99) and HAA (R(2) ≥ 0.83) formation. Higher temperature was found to enhance the DBP formation due to the temperature dependence of reaction rates. Thus, temperature control of pools, especially for those preferring higher temperatures (e.g. hydrotherapy and spa), should take both bather comfort and DBP formation potential into consideration. It is also observed that chlorine competition

  17. Improving Compressed Air System Performance: A Sourcebook for Industry

    SciTech Connect

    2003-11-01

    NREL will produce this sourcebook for DOE's Industrial Technologies Office as part of a series of documents on industrial energy equipment. The sourcebook is a reference for industrial compressed air system users, outlining opportunities to improve system efficiency.

  18. Residential Forced Air System Cabinet Leakage and Blower Performance

    SciTech Connect

    Walker, Iain S.; Dickerhoff, Darryl J.; Delp, William W.

    2010-03-01

    This project evaluated the air leakage and electric power consumption of Residential HVAC components, with a particular focus on air leakage of furnace cabinets. Laboratory testing of HVAC components indicated that air leakage can be significant and highly variable from unit to unit ? indicating the need for a standard test method and specifying maximum allowable air leakage in California State energy codes. To further this effort, this project provided technical assistance for the development of a national standard for Residential HVAC equipment air leakage. This standard is being developed by ASHRAE and is called"ASHRAE Standard 193P - Method of test for Determining the Air Leakage Rate of HVAC Equipment". The final part of this project evaluated techniques for measurement of furnace blower power consumption. A draft test procedure for power consumption was developed in collaboration with the Canadian General Standards Board: CSA 823"Performance Standard for air handlers in residential space conditioning systems".

  19. Application of automated thermal disinfection instead of sterilisation procedures for treatment of rotating dental instruments: efficacy against viruses?

    PubMed

    Rabenau, H F; Nentwig, G H; Doerr, H W

    1997-08-01

    In dentistry it is of primary importance to take into consideration microbial transfer due to the nature of the construction of rotating dental instruments. This aspect was the starting point for our research with the question whether or not sterilisation is fundamentally necessary for slow and high speed hand pieces to make them "safe" out of a virological point of view, or whether a thermal disinfection could also possibly be adequate for this purpose. In this context, we tested the efficiency of the cleaning and disinfection capacity of an automated steam disinfection and sterilisation unit (Sirona Hygiene Center, Siemens, AG, Bensheim) intended to the hygienic treatment of dental instruments with respect to viruses. In model tests the corresponding instruments were experimentally infected with herpes simplex virus type 1 (HSV) and simian vacuoling virus (SV40). As indicator systems we used for both cell cultures (measurement of the degree of infectiosity) and (for HSV) polymerase chain reactions (PCR; determination of viral nucleic acids). In the tests for (residual) infectiosity after thermal disinfection (as an isolated step of the Hygienic Centre) and also for a combination of cleaning and subsequent thermal disinfection (also after protein application), no infectious virus could be found in the interior of the slow handpieces and turbines tested. In opposite to this, infectious HSV and SV40 could be found after completion of every isolated cleaning program in the turbine (in all three ducts) and in the slow handpiece (only in the gearbox duct in the case of HSV, and in the case of SV40 also in the water and air ducts in very small amounts). The PCR analyses showed that no nucleic acids could be found in both instruments (in the air and water ducts) following a practice-relevant combination of cleaning and disinfection, but that PCR-positive signals were obtained for the larger-volume gearbox and drive and return air ducts in 1 or 2 of 3 test samples. The

  20. Application of automated thermal disinfection instead of sterilisation procedures for treatment of rotating dental instruments: efficacy against viruses?

    PubMed

    Rabenau, H F; Nentwig, G H; Doerr, H W

    1997-08-01

    In dentistry it is of primary importance to take into consideration microbial transfer due to the nature of the construction of rotating dental instruments. This aspect was the starting point for our research with the question whether or not sterilisation is fundamentally necessary for slow and high speed hand pieces to make them "safe" out of a virological point of view, or whether a thermal disinfection could also possibly be adequate for this purpose. In this context, we tested the efficiency of the cleaning and disinfection capacity of an automated steam disinfection and sterilisation unit (Sirona Hygiene Center, Siemens, AG, Bensheim) intended to the hygienic treatment of dental instruments with respect to viruses. In model tests the corresponding instruments were experimentally infected with herpes simplex virus type 1 (HSV) and simian vacuoling virus (SV40). As indicator systems we used for both cell cultures (measurement of the degree of infectiosity) and (for HSV) polymerase chain reactions (PCR; determination of viral nucleic acids). In the tests for (residual) infectiosity after thermal disinfection (as an isolated step of the Hygienic Centre) and also for a combination of cleaning and subsequent thermal disinfection (also after protein application), no infectious virus could be found in the interior of the slow handpieces and turbines tested. In opposite to this, infectious HSV and SV40 could be found after completion of every isolated cleaning program in the turbine (in all three ducts) and in the slow handpiece (only in the gearbox duct in the case of HSV, and in the case of SV40 also in the water and air ducts in very small amounts). The PCR analyses showed that no nucleic acids could be found in both instruments (in the air and water ducts) following a practice-relevant combination of cleaning and disinfection, but that PCR-positive signals were obtained for the larger-volume gearbox and drive and return air ducts in 1 or 2 of 3 test samples. The

  1. Disinfecting action of a new multi-purpose disinfection solution for contact lenses.

    PubMed

    Rosenthal, R A; Bell, W M; Abshire, R

    1999-01-01

    The disinfection activity of a new multipurpose disinfection solution (OPTI-FREE Express with ALDOX) was compared to several other contact lens disinfecting solutions. The new solution is preserved with polyquaternium-1 and myristamidopropyl dimethylamine. The other solutions included 3% hydrogen peroxide systems and multipurpose solutions (MPS) preserved with polyhexamethylene biguanide. The products were tested for antimicrobial activity against Staphylococcus spp., Pseudomonas aeruginosa, Serratia marcescens, Candida albicans, Fusarium solani, and Aspergillus fumigatus. OPTI-FREE Express provided a broader range of antimicrobial activity than the MPS. It provided activity similar to that demonstrated by 3% hydrogen peroxide systems, but unlike the hydrogen peroxide system tested, it also prevented re growth of the organisms during extended storage. PMID:16303414

  2. Disinfectants for spacecraft applications - An overview

    NASA Technical Reports Server (NTRS)

    Koenig, David W.; Mallary, Laura L.; Pierson, Duane L.

    1991-01-01

    The review of disinfectants for use on manned missions emphasizes the need for contamination control to prevent the detrimental effects of bacteria growth on crew health. Microbial control is possible by means of biocides, but the selected product has to meet stringent toxicity requirements for the small environments in spacecraft. The testing and evaluation is described of four biocide candidates: hydrogen peroxide, quaternary ammonium compounds, iodine, and glutaraldehyde. The effectiveness of the disinfectants are analyzed in terms of the ability to treat typical microbial counts from Skylab missions in a closed environment. It is shown that many biocide candidates are not compatible with the ECLSS, water-recovery management, and air-revitalization subsystems of the Space Station Freedom. The use of hydrogen peroxide is proposed with a secondary stronger agent for microbial spills from biological experiments.

  3. Cold Vacuum Drying Instrument Air System Design Description (SYS 12)

    SciTech Connect

    SHAPLEY, B.J.; TRAN, Y.S.

    2000-06-05

    This system design description (SDD) addresses the instrument air (IA) system of the spent nuclear fuel (SNF). This IA system provides instrument quality air to the Cold Vacuum Drying (CVD) Facility. The IA system is a general service system that supports the operation of the heating, ventilation, and air conditioning (HVAC) system, the process equipment skids, and process instruments in the CVD Facility. The following discussion is limited to the compressor, dryer, piping, and valving that provide the IA as shown in Drawings H-1-82222, Cold Vacuum Drying Facility Mechanical Utilities Compressed & Instrument Air P&ID, and H-1.82161, Cold Vacuum Drying Facility Process Equipment Skid P&ID MCO/Cusk Interface. Figure 1-1 shows the physical location of the 1A system in the CVD Facility.

  4. Air cycle machine for an aircraft environmental control system

    NASA Technical Reports Server (NTRS)

    Decrisantis, Angelo A. (Inventor); O'Coin, James R. (Inventor); Taddey, Edmund P. (Inventor)

    2010-01-01

    An ECS system includes an ACM mounted adjacent an air-liquid heat exchanger through a diffuser that contains a diffuser plate. The diffuser plate receives airflow from the ACM which strikes the diffuser plate and flows radially outward and around the diffuser plate and into the air-liquid heat exchanger to provide minimal pressure loss and proper flow distribution into the air-liquid heat exchanger with significantly less packaging space.

  5. Commercial Disinfectants During Disinfection Process Validation: More Failures than Success

    PubMed Central

    Chumber, Sushil Kumar; Khanduri, Uma

    2016-01-01

    Introduction Disinfection process validation is mandatory before introduction of a new disinfectant in hospital services. Commercial disinfection brands often question existing hospital policy claiming greater efficacy and lack of toxicity of their products. Inadvertent inadequate disinfection leads to morbidity, patient’s economic burden, and the risk of mortality. Aim To evaluate commercial disinfectants for high, intermediate and low-level disinfection so as to identify utility for our routine situations. Materials and Methods This laboratory based experiment was conducted at St Stephen Hospital, Delhi during July-September 2013. Twelve commercial disinfectants: Sanidex®, Sanocid®, Cidex®, SekuSept Aktiv®, BIB Forte®, Alprojet W®, Desnet®, Sanihygiene®, Incidin®, D125®, Lonzagard®, and Glutishield® were tested. Time-kill assay (suspension test) was performed against six indicator bacteria (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella Typhi, Bacillus cereus, and Mycobacterium fortuitum). Low and high inoculum (final concentrations 1.5X106 and 9X106 cfu/ml) of the first five bacteria while only low level of M. fortuitum was tested. Results Cidex® (2.4% Glutaraldehyde) performed best as high level disinfectant while newer quarternary ammonium compounds (QACs) (Incidin®, D125®, and Lonzagard®) were good at low level disinfection. Sanidex® (0.55% Ortho-pthalaldehyde) though mycobactericidal took 10 minutes for sporicidal activity. Older QAC containing BIB Forte® and Desnet® took 20 minutes to fully inhibit P. aeruginosa. All disinfectants effectively reduced S. Typhi to zero counts within 5 minutes. Conclusion Cidex® is a good high-level disinfectant while newer QACs (Incidin®, D125®, and Lonzagard®) were capable low-level disinfectants. PMID:27656441

  6. Conductive diamond sono-electrochemical disinfection (CDSED) for municipal wastewater reclamation.

    PubMed

    Llanos, Javier; Cotillas, Salvador; Cañizares, Pablo; Rodrigo, Manuel A

    2015-01-01

    In the present work, the disinfection of actual effluents from a municipal wastewater treatment plant (WWTP) by a conductive diamond sono-electrochemical process was assessed. First, efficiency of single electrodisinfection process with diamond anodes (without the contribution of ultrasounds) was studied, finding that the total disinfection can be attained at current charges applied below 0.02kAhm(-3). It was also found that the main disinfection mechanism is the attack of Escherichia coli (E. coli) by the disinfectants produced in the electrochemical cell and that the production of chlorates is avoided when working at current densities not higher than 1.27Am(-2). Next, a marked synergistic effect was found when coupling ultrasound (US) irradiation to the electrochemical system (sono-electrochemical disinfection). This increase in the disinfection rate was found to be related to the suppression of the agglomeration of E. coli cells and the enhancement in the production of disinfectant species.

  7. The potential for optical beam shaping of UV laser sources for mass scale quarantine disinfection applications

    NASA Astrophysics Data System (ADS)

    Lizotte, Todd

    2010-08-01

    Recent events concerning H1N1 "swine flu", have demonstrated to the world the significant potential of rapid increases in death and illness among all age groups and even among the healthy population [1] when a highly infectious influenza virus is introduced. In terms of mass casualties due to a pandemic, preparedness and response planning must be done. One course of action to prevent a pandemic outbreak or reduce the impact of a bioterrorist event is the use of isolation or quarantine facilities. The first level of isolation or quarantine is within the personal residence of the person exposed or infected. In the case where, the specific virus is extremely contagious and its onset of symptoms is rapid and severe, there will be a need for the deployment and setup of larger self contained quarantine facilities. Such facilities are used to house infectious individuals to minimize the exposure of susceptible individuals to contagious individuals, especially when specialized care or treatment is required and during the viral shedding period (5 to 7 days). These types of facilities require non-shared air conditioning, heating and ventilating systems where 100% of air is vented to the outside through a series of disinfection systems and staged filters. Although chemical disinfection is possible, there is a desire to incorporate intense UV radiation as a means to deactivate and disinfect airborne virus within hospital settings and isolated mass scale quarantine facilities. UV radiation is also being considered for disinfection of contaminated surfaces, such as table tops, walls and floors in hospitals and temporary quarantine facilities. In such applications the use of UV bulb technology can create many problems, for instance bulb technology requires numerous bulbs to treat a large volume of air, generates significant heat, uses significant power and does not produce large fluxes of UV light efficiently. This paper provides several methods of creating quarantine level

  8. Position paper -- Tank ventilation system design air flow rates

    SciTech Connect

    Goolsby, G.K.

    1995-01-04

    The purpose of this paper is to document a project position on required ventilation system design air flow rates for the waste storage tanks currently being designed by project W-236A, the Multi-Function Waste Tank Facility (MWTF). The Title 1 design primary tank heat removal system consists of two systems: a primary tank vapor space ventilation system; and an annulus ventilation system. At the conclusion of Title 1 design, air flow rates for the primary and annulus ventilation systems were 960 scfm and 4,400 scfm, respectively, per tank. These design flow rates were capable of removing 1,250,000 Btu/hr from each tank. However, recently completed and ongoing studies have resulted in a design change to reduce the extreme case heat load to 700,000 Btu/hr. This revision of the extreme case heat load, coupled with results of scale model evaporative testing performed by WHC Thermal Hydraulics, allow for a reduction of the design air flow rates for both primary and annulus ventilation systems. Based on the preceding discussion, ICF Kaiser Hanford Co. concludes that the design should incorporate the following design air flow rates: Primary ventilation system--500 scfm maximum and Annulus ventilation system--1,100 scfm maximum. In addition, the minimum air flow rates in the primary and annulus ventilation systems will be investigated during Title 2 design. The results of the Title 2 investigation will determine the range of available temperature control using variable air flows to both ventilation systems.

  9. Bactericidal activity of TiO[sub 2] photocatalyst in aqueous media. Toward a solar-assisted water disinfection system

    SciTech Connect

    Wei, C.; Lin, W.Y.; Zainal, Z.; Williams, N.E.; Zhu, K.; Kruzic, A.P.; Smith, R.L.; Rajeshwar, K. )

    1994-05-01

    Irradiation of suspensions of Escherichia coli ([approximately] 10[sup 6] cells/mL) and TiO[sub 2] (anatase) with UV-visible light of wave-lengths longer than 380 nm resulted in the killing of the bacteria within minutes. Oxygen was found to be a prerequisite for the bactericidal properties of the photocatalyst. Bacterial killing was found to adhere to first-order kinetics. The rate constant was proportional to the square root of the concentration of TiO[sub 2] and proportional to the incident light intensity in the range [approximately] 180- [approximately] 1660 [mu]E s[sup [minus]1] m[sup [minus]2]. The trends in these simulated laboratory experiments were mimicked by outdoor tests conducted under the summer noonday sun in Texas. The implications of these results as well as those of previous investigations in terms of practical applicability to solar-assisted water treatment and disinfection at remote sites are discussed relative to water technologies currently considered as viable as alternatives to chlorination. 24 refs., 8 figs.

  10. DOC, Color and Disinfection By-Product Precursor Dynamics along an Urbanization Gradient, Croton Water Supply System, New York, USA

    NASA Astrophysics Data System (ADS)

    Hassett, J. M.; Mitchell, M. J.; Burns, D. A.; Heisig, P. M.

    2005-05-01

    Hydrologic processes in suburban watersheds and their effects on water quality warrant investigation. Biweekly and storm samples were collected and analyzed for base cations, selected anions, and DOC over a one-year period at the outlet of three small (37 - 55 ha) watersheds (one forested, two with different degrees of suburban development) in the Croton Watershed, southeastern New York. Less frequent sampling for Pt/Co color and disinfection by-product precursors (DBPs) were also conducted. Median baseflow concentrations (>3 days since rainfall) of DOC were similar, ranging from 2.1 to 1.8 to 1.7 mg L -1 for the most urbanized to the forested watershed, respectively. On a unit area load basis (kg ha-1 yr-1), the range was from 8.9 to 6.4 to 5.1, again from most urbanized to forested watershed. All three watersheds showed similar storm responses, with evidence for a flushing mechanism in that DOC concentration increased with increasing discharge. Pt/Co color and DBPs (determined as both total trihalomethane and total haloacetic acid formation potentials) showed similar storm behavior, although the range of response was greater than observed for DOC, suggesting a labile DOC fraction was mobilized during storm events. The more urbanized watersheds tended to favor brominated over chlorinated forms of DBPs; the reasons for this are unclear.

  11. Designing Forced-Air HVAC Systems

    SciTech Connect

    2010-08-31

    This guide explains proper calculation of heating and cooling design loads for homes.used to calculated for the home using the protocols set forth in the latest edition of the Air Conditioning Contractors of America’s (ACCA) Manual J (currently the 8th edition), ASHRAE 2009 Handbook of Fundamentals, or an equivalent computation procedure.

  12. IDENTIFICATION OF TI02/UV DISINFECTION BYPRODUCTS IN DRINKING WATER

    EPA Science Inventory

    Due to concern over the presence of trihalomethanes (THMs) and other chlorinated byproducts in chlorinated drinking water, alternative disinfection methods are being explored. One of the alternative treatment methods currently being evaluated for potential use with small systems ...

  13. USEPA Research on Monochloramine Disinfection Kinetics of Nitrosomonas Europaea

    EPA Science Inventory

    Based on utility surveys, 30 to 63% of utilities practicing chloramination for secondary disinfection experience nitrification episodes (American Water Works Association 2006). Nitrification in drinking water distribution systems is undesirable and may result in water quality deg...

  14. US EPA Research on Monochloramine Disinfection Kinetics of Nitrosomonas europaea

    EPA Science Inventory

    Based on utility surveys, 30 to 63% of utilities practicing chloramination for secondary disinfection experience nitrification episodes (American Water Works Association 2006). Nitrification in drinking water distribution systems is undesirable and may result in water quality deg...

  15. Three-Dimensional Air Quality System (3D-AQS)

    NASA Astrophysics Data System (ADS)

    Engel-Cox, J.; Hoff, R.; Weber, S.; Zhang, H.; Prados, A.

    2007-12-01

    The 3-Dimensional Air Quality System (3DAQS) integrates remote sensing observations from a variety of platforms into air quality decision support systems at the U.S. Environmental Protection Agency (EPA), with a focus on particulate air pollution. The decision support systems are the Air Quality System (AQS) / AirQuest database at EPA, Infusing satellite Data into Environmental Applications (IDEA) system, the U.S. Air Quality weblog (Smog Blog) at UMBC, and the Regional East Atmospheric Lidar Mesonet (REALM). The project includes an end user advisory group with representatives from the air quality community providing ongoing feedback. The 3DAQS data sets are UMBC ground based LIDAR, and NASA and NOAA satellite data from MODIS, OMI, AIRS, CALIPSO, MISR, and GASP. Based on end user input, we are co-locating these measurements to the EPA's ground-based air pollution monitors as well as re-gridding to the Community Multiscale Air Quality (CMAQ) model grid. These data provide forecasters and the scientific community with a tool for assessment, analysis, and forecasting of U.S Air Quality. The third dimension and the ability to analyze the vertical transport of particulate pollution are provided by aerosol extinction profiles from the UMBC LIDAR and CALIPSO. We present examples of a 3D visualization tool we are developing to facilitate use of this data. We also present two specific applications of 3D-AQS data. The first is comparisons between PM2.5 monitor data and remote sensing aerosol optical depth (AOD) data, which show moderate agreement but variation with EPA region. The second is a case study for Baltimore, Maryland, as an example of 3D-analysis for a metropolitan area. In that case, some improvement is found in the PM2.5 /LIDAR correlations when using vertical aerosol information to calculate an AOD below the boundary layer.

  16. Attenuating noise generated by variable-air-volume systems

    SciTech Connect

    Stokes, R.

    1985-03-01

    Sound generated by HVAC systems is receiving much attention because they are generally the principal contributors to room background sound levels that may become irritating and distracting noise if not controlled. This article discusses the creation of a quiet working environment through an analysis of the three traditional sound paths associated with air handling systems: radiated sound, inlet or return air sound and discharge sound. Recommended standards are given as well as a brief overview of materials used to fabricate HVAC system components.

  17. 14 CFR 33.66 - Bleed air system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.66 Bleed air system. The engine must supply bleed air without adverse effect on the engine, excluding reduced thrust or...

  18. Compressed air systems. A guidebook on energy and cost savings

    SciTech Connect

    Not Available

    1984-03-30

    This guidebook shows how energy can be saved in compressed air systems. It discusses basic compressed air systems which are typical of those found in industry and describes them and the engineering practices behind them. Energy conservation recommendations follow. These recommendations cover equipment selection, design, maintenance, and operation. Included is information which will help the reader to make economic evaluations of various engineering and equipment alternatives as they affect operations and costs. The appendices include some modern computer based approaches to predicting pressure drop for designing compressed air distribution systems. Also included is a bibliography providing leads for further and more detailed technical information on these and related subjects.

  19. Cytotoxicity assessment of residual high-level disinfectants.

    PubMed

    Ryu, Mizuyuki; Kobayashi, Toshihiro; Kawamukai, Emiko; Quan, Glenlelyn; Furuta, Taro

    2013-01-01

    Some studies show the uptake of disinfectants on medical devices but no studies on their cytotoxicity have been reported. This study aimed to assess that cytotoxicity in a 3-dimensional culture system using HeLa cells grown in matrices composed of collagen. Plastic materials were soaked in the use solutions of the widely used high-level disinfectants, glutaraldehyde (GA), ortho-phthalaldehyde (OPA) and peracetic acid (PAA). After being rinsed, they were allowed to dry and were embedded into the cell medium to investigate the cytotoxicity of the residual disinfectants. Cytotoxicity was observed with the polyvinyl chloride, polyurethane and silicon tubes soaked in GA and OPA, indicating that both disinfectants were absorbed in the test pieces, whereas for PAA, none was observed. As for the polytetrafluoroethylene (PTFE) tubes, no disinfectant displayed cytotoxicity. GA and OPA are primary irritants, having a potential to cause anaphylaxis and other forms of allergic reactions. There should be consideration not only about the toxicity of the residual disinfectant from poor rinsing, but also about the toxicity that would result from the disinfectants that were absorbed and consequently released from the medical devices or materials.

  20. Cytotoxicity assessment of residual high-level disinfectants.

    PubMed

    Ryu, Mizuyuki; Kobayashi, Toshihiro; Kawamukai, Emiko; Quan, Glenlelyn; Furuta, Taro

    2013-01-01

    Some studies show the uptake of disinfectants on medical devices but no studies on their cytotoxicity have been reported. This study aimed to assess that cytotoxicity in a 3-dimensional culture system using HeLa cells grown in matrices composed of collagen. Plastic materials were soaked in the use solutions of the widely used high-level disinfectants, glutaraldehyde (GA), ortho-phthalaldehyde (OPA) and peracetic acid (PAA). After being rinsed, they were allowed to dry and were embedded into the cell medium to investigate the cytotoxicity of the residual disinfectants. Cytotoxicity was observed with the polyvinyl chloride, polyurethane and silicon tubes soaked in GA and OPA, indicating that both disinfectants were absorbed in the test pieces, whereas for PAA, none was observed. As for the polytetrafluoroethylene (PTFE) tubes, no disinfectant displayed cytotoxicity. GA and OPA are primary irritants, having a potential to cause anaphylaxis and other forms of allergic reactions. There should be consideration not only about the toxicity of the residual disinfectant from poor rinsing, but also about the toxicity that would result from the disinfectants that were absorbed and consequently released from the medical devices or materials. PMID:24366628

  1. Evaluation of a pulsed xenon ultraviolet disinfection system for reduction of healthcare-associated pathogens in hospital rooms.

    PubMed

    Nerandzic, Michelle M; Thota, Priyaleela; Sankar C, Thriveen; Jencson, Annette; Cadnum, Jennifer L; Ray, Amy J; Salata, Robert A; Watkins, Richard R; Donskey, Curtis J

    2015-02-01

    OBJECTIVE To determine the effectiveness of a pulsed xenon ultraviolet (PX-UV) disinfection device for reduction in recovery of healthcare-associated pathogens. SETTING Two acute-care hospitals. METHODS We examined the effectiveness of PX-UV for killing of Clostridium difficile spores, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) on glass carriers and evaluated the impact of pathogen concentration, distance from the device, organic load, and shading from the direct field of radiation on killing efficacy. We compared the effectiveness of PX-UV and ultraviolet-C (UV-C) irradiation, each delivered for 10 minutes at 4 feet. In hospital rooms, the frequency of native pathogen contamination on high-touch surfaces was assessed before and after 10 minutes of PX-UV irradiation. RESULTS On carriers, irradiation delivered for 10 minutes at 4 feet from the PX-UV device reduced recovery of C. difficile spores, MRSA, and VRE by 0.55±0.34, 1.85±0.49, and 0.6±0.25 log10 colony-forming units (CFU)/cm2, respectively. Increasing distance from the PX-UV device dramatically reduced killing efficacy, whereas pathogen concentration, organic load, and shading did not. Continuous UV-C achieved significantly greater log10CFU reductions than PX-UV irradiation on glass carriers. On frequently touched surfaces, PX-UV significantly reduced the frequency of positive C. difficile, VRE, and MRSA culture results. CONCLUSIONS The PX-UV device reduced recovery of MRSA, C. difficile, and VRE on glass carriers and on frequently touched surfaces in hospital rooms with a 10-minute UV exposure time. PX-UV was not more effective than continuous UV-C in reducing pathogen recovery on glass slides, suggesting that both forms of UV have some effectiveness at relatively short exposure times.

  2. Microbial contamination and disinfection methods of pacifiers

    PubMed Central

    NELSON, Paulo; LOUVAIN, Márcia Costa; MACARI, Soraia; LUCISANO, Marília Pacífico; da SILVA, Raquel Assed Bezerra; de QUEIROZ, Alexandra Mussolino; GATON-HERNÁNDEZ, Patrícia; da SILVA, Léa Assed Bezerra

    2015-01-01

    Objectives To evaluate the microbial contamination of pacifiers by Mutans Streptococci (MS) and the efficacy of different methods for their disinfection. Methods Twenty-eight children were assigned to a 4-stage changeover system with a 1-week interval. In each stage, children received a new pacifier and the parents were instructed to maintain their normal habits for 1 week. After this time, the pacifiers were subjected to the following 4 disinfection methods: spraying with 0.12% chlorhexidine solution, Brushtox® or sterile tap water, and immersion in boiling tap water for 15 minutes. Microbiological culture for MS and Scanning Electron Microscopy (SEM) were performed. The results were analyzed statistically by Friedman’s non-parametric test (a=0.05). Results The 0.12% chlorhexidine spray was statistically similar to the boiling water (p>0.05) and more effective than the Brushtox® spray and control (p<0.05). The analysis of SEM showed the formation of a cariogenic biofilm in all groups with positive culture. Conclusions Pacifiers become contaminated by MS after their use by children and should be disinfected routinely. Spraying with a 0.12% chlorhexidine solution and immersion in boiling water promoted better disinfection of the pacifiers compared with a commercial antiseptic toothbrush cleanser (Brushtox®). PMID:26537723

  3. Monochloramine disinfection kinetics of Nitrosomonas europaea using propidium monoazide quantitative real-time PCR (PMA-qPCR)

    EPA Science Inventory

    As a result of the implementation of the Stage 1 and Stage 2 Disinfectants and Disinfection Byproduct Rules, monochloramine use as a secondary disinfectant in the United States is predicted to increase to 57% of all surface and 7% of all ground water treatment systems. In additi...

  4. The Adverse Effects of Air Pollution on the Nervous System

    PubMed Central

    Genc, Sermin; Zadeoglulari, Zeynep; Fuss, Stefan H.; Genc, Kursad

    2012-01-01

    Exposure to ambient air pollution is a serious and common public health concern associated with growing morbidity and mortality worldwide. In the last decades, the adverse effects of air pollution on the pulmonary and cardiovascular systems have been well established in a series of major epidemiological and observational studies. In the recent past, air pollution has also been associated with diseases of the central nervous system (CNS), including stroke, Alzheimer's disease, Parkinson's disease, and neurodevelopmental disorders. It has been demonstrated that various components of air pollution, such as nanosized particles, can easily translocate to the CNS where they can activate innate immune responses. Furthermore, systemic inflammation arising from the pulmonary or cardiovascular system can affect CNS health. Despite intense studies on the health effects of ambient air pollution, the underlying molecular mechanisms of susceptibility and disease remain largely elusive. However, emerging evidence suggests that air pollution-induced neuroinflammation, oxidative stress, microglial activation, cerebrovascular dysfunction, and alterations in the blood-brain barrier contribute to CNS pathology. A better understanding of the mediators and mechanisms will enable the development of new strategies to protect individuals at risk and to reduce detrimental effects of air pollution on the nervous system and mental health. PMID:22523490

  5. Combined air stripper/membrane vapor separation systems. Final report

    SciTech Connect

    Wijmans, J.G.; Baker, R.W.; Kamaruddin, H.D.; Kaschemekat, J.; Olsen, R.P.; Rose, M.E.; Segelke, S.V.

    1992-11-01

    Air stripping is an economical and efficient method of removing dissolved volatile organic compounds (VOCs) from contaminated groundwater. Air strippers, however, produce a vent air stream, which must meet the local air quality limits. If the VOC content exceeds the limits, direct discharge is not possible; therefore, a carbon adsorption VOC capture system is used to treat the vent air. This treatment step adds a cost of at least $50/lb of VOC captured. In this program, a combined air stripper/membrane vapor separation system was constructed and demonstrated in the laboratory. The membrane system captures VOCs from the stripper vent stream at a projected cost of $15/lb VOC for a water VOC content of 5 ppmw, and $75/lb VOC for a water VOC content of 1 ppmw. The VOCs are recovered as a small, concentrated liquid fraction for disposal or solvent recycling. The concept has been demonstrated in experiments with a system capable of handling up to 150,000 gpd of water. The existing demonstration system is available for field tests at a DOE facility or remediation site. Replacement of the current short air stripping tower (effective height 3 m) with a taller tower is recommended to improve VOC removal.

  6. Prototype air cleaning system for a firing range

    SciTech Connect

    Glissmeyer, J.A.; Mishima, J.; Bamberger, J.A.

    1985-01-01

    This report recommends air cleaning system components for the US Army Ballistics Research Laboratory's new large-caliber firing range, which is used for testing depleted uranium (DU) penetrators. The new air cleaning system has lower operating costs during the life of the system compared to that anticipated for the existing air cleaning system. The existing system consists of three banks of filters in series; the first two banks are prefilters and the last are high-efficiency particulate air (HEPA) filters. The principal disadvantage of the existing filters is that they are not cleanable and reusable. Pacific Northwest Laboratory focused the search for alternate air cleaning equipment on devices that do not employ liquids as part of the particle collection mechanism. Collected dry particles were assumed preferable to a liquid waste stream. The dry particle collection devices identified included electrostatic precipitators; inertial separators using turning vanes or cyclones; and several devices employing a filter medium such as baghouses, cartridge houses, cleanable filters, and noncleanable filters similar to those in the existing system. The economics of practical air cleaning systems employing the dry particle collection devices were evaluated in 294 different combinations. 7 references, 21 figures, 78 tables.

  7. 7. Northeast view interior, air traffic control and landing system ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Northeast view interior, air traffic control and landing system room 25 - Selfridge Field, Building No. 1050, Northwest corner of Doolittle Avenue & D Street; Harrison Township, Mount Clemens, Macomb County, MI

  8. Technology options for an enhanced air cargo system

    NASA Technical Reports Server (NTRS)

    Winston, M. M.

    1979-01-01

    A view of potential enhancements to the air cargo system through technology application is provided. NASA's role in addressing deficiencies of the current civil and military air cargo systems is outlined. The evolution of conventional airfreighter design is traced and projected through the 1990's. Also, several advanced airfreighter concepts incorporating unconventional design features are described to show their potentials benefits. A number of ongoing NASA technology programs are discussed to indicate the wide range of advanced technologies offering potential benefits to the air cargo system. The promise of advanced airfreighters is then viewed in light of the future air cargo infrastructure predicted by extensive systems studies. The derived outlook concludes that the aircraft technology benefits may be offset somewhat by adverse economic, environmental, and institutional constraints.

  9. View of building 11070 showing vents and forced air system ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of building 11070 showing vents and forced air system on east side, looking southwest. - Naval Ordnance Test Station Inyokern, China Lake Pilot Plant, Maintenance Shop, C Street, China Lake, Kern County, CA

  10. Air cushion landing system stability study

    NASA Astrophysics Data System (ADS)

    Burton, T. D.

    1981-02-01

    An analysis of an inelastic ACLS plunge mode dynamic model is presented. The ACLS has unrestrained side elements and frozen end elements. The model exhibits unstable behavior at certain operating conditions for which the side elements are in contact with the ground. A linear analysis showed this instability to be due mainly to the altitude sensitivities of the cushion to atmosphere airflows and the attendant influence on the dynamic pressure forces on the vehicle. The model instability can be alleviated by isolating side and end elements so that they are all unrestrained and by simultaneously venting the air cushion directly to atmosphere.

  11. 9. Water Purification System and Instrument Air Receiver Tank, view ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Water Purification System and Instrument Air Receiver Tank, view to the south. The water purification system is visible in the right foreground of the photograph and the instrument air receiver tank is visible in the right background of the photograph. - Washington Water Power Clark Fork River Cabinet Gorge Hydroelectric Development, Powerhouse, North Bank of Clark Fork River at Cabinet Gorge, Cabinet, Bonner County, ID

  12. A reliability study of instrument air system design options

    SciTech Connect

    Guey, C.; Skelley, W. ); Gilbert, L.; Anoba, R.; Stutzke, M. )

    1992-01-01

    The existing instrument air system at Turkey Point station uses mobile diesel-driven air compressors. Although these diesel compressors have performed their function well, they represent a maintenance and financial burden requiring engineering review. An engineering evaluation is ongoing to develop several feasible conceptual design options to upgrade the instrument air systems. This phase-1 study was performed to assess the reliability of the various proposed design options. A phase-2 study will be conducted later to determine the core damage frequency for a selected option.

  13. Air data system optimization using a genetic algorithm

    NASA Technical Reports Server (NTRS)

    Deshpande, Samir M.; Kumar, Renjith R.; Seywald, Hans; Siemers, Paul M., III

    1992-01-01

    An optimization method for flush-orifice air data system design has been developed using the Genetic Algorithm approach. The optimization of the orifice array minimizes the effect of normally distributed random noise in the pressure readings on the calculation of air data parameters, namely, angle of attack, sideslip angle and freestream dynamic pressure. The optimization method is applied to the design of Pressure Distribution/Air Data System experiment (PD/ADS) proposed for inclusion in the Aeroassist Flight Experiment (AFE). Results obtained by the Genetic Algorithm method are compared to the results obtained by conventional gradient search method.

  14. Controlling Legionella and Pseudomonas aeruginosa re-growth in therapeutic spas: implementation of physical disinfection treatments, including UV/ultrafiltration, in a respiratory hydrotherapy system.

    PubMed

    Leoni, E; Sanna, T; Zanetti, F; Dallolio, L

    2015-12-01

    The study aimed to assess the efficacy of an integrated water safety plan (WSP) in controlling Legionella re-growth in a respiratory hydrotherapy system located in a spa centre, supplied with sulphurous water, which was initially colonized by Legionella pneumophila. Heterotrophic plate counts, Pseudomonas aeruginosa, Legionella spp. were detected in water samples taken 6-monthly from the hydrotherapy equipment (main circuit, entry to benches, final outlets). On the basis of the results obtained by the continuous monitoring and the changes in conditions, the original WSP, including physical treatments of water and waterlines, environmental surveillance and microbiological monitoring, was integrated introducing a UV/ultrafiltration system. The integrated treatment applied to the sulphurous water (microfiltration/UV irradiation/ultrafiltration), waterlines (superheated stream) and distal outlets (descaling/disinfection of nebulizers and nasal irrigators), ensured the removal of Legionella spp. and P. aeruginosa and a satisfactory microbiological quality over time. The environmental surveillance was successful in evaluating the hazard and identifying the most suitable preventive strategies to avoid Legionella re-growth. Ultrafiltration is a technology to take into account in the control of microbial contamination of therapeutic spas, since it does not modify the chemical composition of the water, thus allowing it to retain its therapeutic properties. PMID:26608761

  15. Controlling Legionella and Pseudomonas aeruginosa re-growth in therapeutic spas: implementation of physical disinfection treatments, including UV/ultrafiltration, in a respiratory hydrotherapy system.

    PubMed

    Leoni, E; Sanna, T; Zanetti, F; Dallolio, L

    2015-12-01

    The study aimed to assess the efficacy of an integrated water safety plan (WSP) in controlling Legionella re-growth in a respiratory hydrotherapy system located in a spa centre, supplied with sulphurous water, which was initially colonized by Legionella pneumophila. Heterotrophic plate counts, Pseudomonas aeruginosa, Legionella spp. were detected in water samples taken 6-monthly from the hydrotherapy equipment (main circuit, entry to benches, final outlets). On the basis of the results obtained by the continuous monitoring and the changes in conditions, the original WSP, including physical treatments of water and waterlines, environmental surveillance and microbiological monitoring, was integrated introducing a UV/ultrafiltration system. The integrated treatment applied to the sulphurous water (microfiltration/UV irradiation/ultrafiltration), waterlines (superheated stream) and distal outlets (descaling/disinfection of nebulizers and nasal irrigators), ensured the removal of Legionella spp. and P. aeruginosa and a satisfactory microbiological quality over time. The environmental surveillance was successful in evaluating the hazard and identifying the most suitable preventive strategies to avoid Legionella re-growth. Ultrafiltration is a technology to take into account in the control of microbial contamination of therapeutic spas, since it does not modify the chemical composition of the water, thus allowing it to retain its therapeutic properties.

  16. Transformations in Air Transportation Systems For the 21st Century

    NASA Technical Reports Server (NTRS)

    Holmes, Bruce J.

    2004-01-01

    Globally, our transportation systems face increasingly discomforting realities: certain of the legacy air and ground infrastructures of the 20th century will not satisfy our 21st century mobility needs. The consequence of inaction is diminished quality of life and economic opportunity for those nations unable to transform from the 20th to 21st century systems. Clearly, new thinking is required regarding business models that cater to consumers value of time, airspace architectures that enable those new business models, and technology strategies for innovating at the system-of-networks level. This lecture proposes a structured way of thinking about transformation from the legacy systems of the 20th century toward new systems for the 21st century. The comparison and contrast between the legacy systems of the 20th century and the transformed systems of the 21st century provides insights into the structure of transformation of air transportation. Where the legacy systems tend to be analog (versus digital), centralized (versus distributed), and scheduled (versus on-demand) for example, transformed 21st century systems become capable of scalability through technological, business, and policy innovations. Where air mobility in our legacy systems of the 20th century brought economic opportunity and quality of life to large service markets, transformed air mobility of the 21st century becomes more equitable available to ever-thinner and widely distributed populations. Several technological developments in the traditional aircraft disciplines as well as in communication, navigation, surveillance and information systems create new foundations for 21st thinking about air transportation. One of the technological developments of importance arises from complexity science and modern network theory. Scale-free (i.e., scalable) networks represent a promising concept space for modeling airspace system architectures, and for assessing network performance in terms of robustness

  17. An Air Quality Data Analysis System for Interrelating Effects, Standards and Needed Source Reductions

    ERIC Educational Resources Information Center

    Larsen, Ralph I.

    1973-01-01

    Makes recommendations for a single air quality data system (using average time) for interrelating air pollution effects, air quality standards, air quality monitoring, diffusion calculations, source-reduction calculations, and emission standards. (JR)

  18. Investigation on wind energy-compressed air power system.

    PubMed

    Jia, Guang-Zheng; Wang, Xuan-Yin; Wu, Gen-Mao

    2004-03-01

    Wind energy is a pollution free and renewable resource widely distributed over China. Aimed at protecting the environment and enlarging application of wind energy, a new approach to application of wind energy by using compressed air power to some extent instead of electricity put forward. This includes: explaining the working principles and characteristics of the wind energy-compressed air power system; discussing the compatibility of wind energy and compressor capacity; presenting the theoretical model and computational simulation of the system. The obtained compressor capacity vs wind power relationship in certain wind velocity range can be helpful in the designing of the wind power-compressed air system. Results of investigations on the application of high-pressure compressed air for pressure reduction led to conclusion that pressure reduction with expander is better than the throttle regulator in energy saving.

  19. Autonomous Integrated Receive System (AIRS) requirements definition. Volume 4: Functional specification for the prototype Automated Integrated Receive System (AIRS)

    NASA Technical Reports Server (NTRS)

    Chie, C. M.

    1984-01-01

    The functional requirements for the performance, design, and testing for the prototype Automated Integrated Receive System (AIRS) to be demonstrated for the TDRSS S-Band Single Access Return Link are presented.

  20. Register Closing Effects on Forced Air Heating System Performance

    SciTech Connect

    Walker, Iain S.

    2003-11-01

    Closing registers in forced air heating systems and leaving some rooms in a house unconditioned has been suggested as a method of quickly saving energy for California consumers. This study combined laboratory measurements of the changes in duct leakage as registers are closed together with modeling techniques to estimate the changes in energy use attributed to closing registers. The results of this study showed that register closing led to increased energy use for a typical California house over a wide combination of climate, duct leakage and number of closed registers. The reduction in building thermal loads due to conditioning only a part of the house was offset by increased duct system losses; mostly due to increased duct leakage. Therefore, the register closing technique is not recommended as a viable energy saving strategy for California houses with ducts located outside conditioned space. The energy penalty associated with the register closing technique was found to be minimized if registers furthest from the air handler are closed first because this tends to only affect the pressures and air leakage for the closed off branch. Closing registers nearer the air handler tends to increase the pressures and air leakage for the whole system. Closing too many registers (more than 60%) is not recommended because the added flow resistance severely restricts the air flow though the system leading to safety concerns. For example, furnaces may operate on the high-limit switch and cooling systems may suffer from frozen coils.

  1. DISINFECTION BYPRODUCTS: THE NEXT GENERATION

    EPA Science Inventory

    Disinfection of drinking water is rightly hailed as a major public health triumph of the 20th Century. Before widespread disinfection of drinking water in the U.S. and Europe, millions of people died from infectious waterborne diseases, such as typhoid and cholera. The microbia...

  2. Sanitizers and Disinfectants Guide. Revised

    ERIC Educational Resources Information Center

    Healthy Schools Network, Inc., 2012

    2012-01-01

    Sanitizers and disinfectants can play an important role in protecting public health. They are designed to kill "pests," including infectious germs and other microorganisms such as bacteria, viruses, and fungi. Unfortunately, sanitizers and disinfectants also contain chemicals that are "pesticides." Exposure to persistent toxic chemicals in…

  3. Advanced air revitalization system modeling and testing

    NASA Technical Reports Server (NTRS)

    Dall-Baumann, Liese; Jeng, Frank; Christian, Steve; Edeer, Marybeth; Lin, Chin

    1990-01-01

    To support manned lunar and Martian exploration, an extensive evaluation of air revitalization subsystems (ARS) is being conducted. The major operations under study include carbon dioxide removal and reduction; oxygen and nitrogen production, storage, and distribution; humidity and temperature control; and trace contaminant control. A comprehensive analysis program based on a generalized block flow model was developed to facilitate the evaluation of various processes and their interaction. ASPEN PLUS was used in modelling carbon dioxide removal and reduction. Several life support test stands were developed to test new and existing technologies for their potential applicability in space. The goal was to identify processes which use compact, lightweight equipment and maximize the recovery of oxygen and water. The carbon dioxide removal test stands include solid amine/vacuum desorption (SAVD), regenerative silver oxide chemisorption, and electrochemical carbon dioxide concentration (EDC). Membrane-based carbon dioxide removal and humidity control, catalytic reduction of carbon dioxide, and catalytic oxidation of trace contaminants were also investigated.

  4. Electronic control system for air fuel ratio compensation in highlands

    SciTech Connect

    Kimura, J.; Noji, A.

    1981-12-29

    An electronic control system which electronically controls the air fuel ratio of a mixture being supplied to a gasoline engine in highlands is described. An orifice device is provided in a passage through which secondary air is supplied to the venturi section of the engine carburetor. An electronic control unit carries out programmed control of the orifice opening of the orifice device in response to the atmospheric pressure and the engine temperature to create a reference pressure. A further electronic control unit drives a second air control valve provided in the secondary air supply passage along a predetermined operating characteristic pattern in response to the difference between the reference pressure and an actual pressure present in the venturi section of the carburetor. A mixture having an optimum air fuel ratio corresponding to the atmospheric pressure can thus be supplied to the engine from the carburetor.

  5. Performance of a photovoltaically powered air-conditioning system

    SciTech Connect

    Kern, Jr, E. C.; Millner, A. R.

    1980-01-01

    A vapor-compression air conditioner coupled directly to a photovoltaic array is discussed. Previous analyses of such a system are reviewed, and a development system designed to test the concept is described. Preliminary experiments indicate that the performance of this initial system falls considerably short of analytic expectations.

  6. Retrofitting Air Conditioning and Duct Systems in Hot, Dry Climates

    SciTech Connect

    Shapiro, C.; Aldrich, R.; Arena, L.

    2012-07-01

    This technical report describes CARB's work with Clark County Community Resources Division in Las Vegas, Nevada, to optimize procedures for upgrading cooling systems on existing homes in the area to implement health, safety, and energy improvements. Detailed monitoring of five AC systems showed that three of the five systems met or exceeded air flow rate goals.

  7. Multi-hole pressure probes to air data system for subsonic small-scale air vehicles

    NASA Astrophysics Data System (ADS)

    Shevchenko, A. M.; Berezin, D. R.; Puzirev, L. N.; Tarasov, A. Z.; Kharitonov, A. M.; Shmakov, A. S.

    2016-10-01

    A brief review of research performed to develop multi-hole probes to measure of aerodynamic angles, dynamic head, and static pressure of a flying vehicle. The basis of these works is the application a well-known classical multi-hole pressure probe technique of measuring of a 3D flow to use in the air data system. Two multi-hole pressure probes with spherical and hemispherical head to air-data system for subsonic small-scale vehicles have been developed. A simple analytical probe model with separation of variables is proposed. The probes were calibrated in the wind tunnel, one of them is in-flight tested.

  8. Microbiological Evaluation of a Range of Disinfectant Products To Control Mixed-Species Biofilm Contamination in a Laboratory Model of a Dental Unit Water System

    PubMed Central

    Walker, J. T.; Bradshaw, D. J.; Fulford, M. R.; Marsh, P. D.

    2003-01-01

    Dental unit water system (DUWS) tubing harbors complex multispecies biofilms that are responsible for high microbial levels at the distal outlet. The aim of this study was to use an established biofilm laboratory model to simulate biofouling of DUWS to evaluate practical, cost-effective, and evidence-based methods of microbial decontamination. Reproducible biofilms were developed in the model over 14 days; decontamination was assessed using total viable counts (TVC) and microscopic-image analysis techniques to view the inner surface of tubing. Flushing did not reduce the biofilm coverage or TVC. Combizyme and ozone did not completely eliminate the viable bacteria (70 and 65% reduction in biofilm TVC, respectively), nor did they remove the biofilm (45 and 57% reduction in biofilm coverage, respectively). Chlorhexidine and Bio2000 (active agent: ethanol and chlorhexidine), Tegodor and Gigasept Rapid (aldehyde based), and Grotanol (hydroxide based) completely eliminated the TVC but did not completely remove biofilm (31, 53 33, 34, and 64.9% reduction of biofilm coverage, respectively). Other products including Grotanol Flussig (phenol based), Betadine (povidone-iodine based), Alpron (chlorite based), and the hydroxide-containing products Sporklenz, Sterilex Ultra, Dialox, Sterilox, Sanosil, Oxigenal, and Grotanat Bohrerbad resulted in a 100% reduction in the biofilm TVC and a >95% reduction in biofilm coverage. The study demonstrated that while many disinfectants achieve a sufficient reduction in TVC they may not necessarily remove unwanted biofilm from the tubing surfaces as tested in this laboratory-controlled biofilm model. PMID:12788733

  9. Air-flow regulation system for a coal gasifier

    DOEpatents

    Fasching, George E.

    1984-01-01

    An improved air-flow regulator for a fixed-bed coal gasifier is provided which allows close air-flow regulation from a compressor source even though the pressure variations are too rapid for a single primary control loop to respond. The improved system includes a primary controller to control a valve in the main (large) air supply line to regulate large slow changes in flow. A secondary controller is used to control a smaller, faster acting valve in a secondary (small) air supply line parallel to the main line valve to regulate rapid cyclic deviations in air flow. A low-pass filter with a time constant of from 20 to 50 seconds couples the output of the secondary controller to the input of the primary controller so that the primary controller only responds to slow changes in the air-flow rate, the faster, cyclic deviations in flow rate sensed and corrected by the secondary controller loop do not reach the primary controller due to the high frequency rejection provided by the filter. This control arrangement provides at least a factor of 5 improvement in air-flow regulation for a coal gasifier in which air is supplied by a reciprocating compressor through a surge tank.

  10. Underfloor air distribution systems: Benefits and when to use the system in building design

    SciTech Connect

    McCarry, B.T.

    1995-12-31

    Underfloor air distribution systems are a viable option for mechanical system building design. They are comprised of raised floor panels with a supply air plenum in the void between the raised floor and the concrete structure. Supply air grilles are flush mounted to the floor to create a flat floor and walking surface. The engineering challenge is to determine when to use underfloor air distribution systems and how to effectively apply them. The best places to use this system are in owner-occupied buildings with a high churn rate and/or frequent technology changes. The benefits of this system include fresh air at the level where building occupants are located, forgiveness for variations in internal cooling loads, easy relocation of the supply air grilles to suit revised layouts, a reduction in energy costs for the mechanical system, and an improvement in indoor air quality.

  11. Disinfection of pumice.

    PubMed

    Setz, J; Heeg, P

    1996-10-01

    Pumice is a potential source of infection for the dental technician and of cross-contamination between different dentures and patients. In this study, the number of microorganisms in two different combinations of pumice and disinfectant was compared with a conventional mixture of pumice and water. The results revealed that under practical conditions the mix of Steribim (pumice containing benzoic acid added by the manufacturer) with water reduced the number of bacteria by 99% compared with a mix of a conventional pumice and water. The addition of an antiseptic product that contained octenidine as active agent to conventional pumice reduced the number of microorganisms by 99.999%.

  12. Measurement results obtained from air quality monitoring system

    SciTech Connect

    Turzanski, P.K.; Beres, R.

    1995-12-31

    An automatic system of air pollution monitoring operates in Cracow since 1991. The organization, assembling and start-up of the network is a result of joint efforts of the US Environmental Protection Agency and the Cracow environmental protection service. At present the automatic monitoring network is operated by the Provincial Inspection of Environmental Protection. There are in total seven stationary stations situated in Cracow to measure air pollution. These stations are supported continuously by one semi-mobile (transportable) station. It allows to modify periodically the area under investigation and therefore the 3-dimensional picture of creation and distribution of air pollutants within Cracow area could be more intelligible.

  13. Integration of air separation membrane and coalescing filter for use on an inlet air system of an engine

    DOEpatents

    Moncelle, Michael E.

    2003-01-01

    An intake air separation system suitable for combustion air of an internal combustion engine. An air separation device of the system includes a plurality of fibers, each fiber having a tube with a permeation barrier layer on the outer surface thereof and a coalescing layer on the inner surface thereof, to restrict fluid droplets from contacting the permeation barrier layer.

  14. Occurrence and exposures to disinfectants and disinfection by-products

    SciTech Connect

    Cumming, R.B.; Jolley, R.L.

    1992-12-31

    Disinfection by-products are associated with all chemical disinfectants. The concentration and toxic nature of the disinfection byproducts (DBPs) is a direct function of the chemical nature of the disinfectant itself and/or of the chemical reactions of the disinfectant with reaction substrates in the water, especially organic constituents. A principal advantage of biological and physical water treatment processes, such as filtration, is the lack of chemical reactions producing disinfectant-related DBPs. The use of the highest quality source water available is important for minimization of DBP formation. In lieu of such high quality water, improvement of water quality by removal of DBP precursors through filtration or other means before application of chemical disinfectants is important. Most, if not all, water treatment experts are aware of these simplistic axioms. In view of the increasing knowledge being developed concerning DBPs including the identification of ``new`` DBPs, prudence dictates minimization of DBP formation. Wholesome drinking water is perhaps the biggest economic bargain available to consumers. The cost-effectiveness of water quality improvement should be evaluated with that in mind.

  15. Occurrence and exposures to disinfectants and disinfection by-products

    SciTech Connect

    Cumming, R.B.; Jolley, R.L.

    1992-01-01

    Disinfection by-products are associated with all chemical disinfectants. The concentration and toxic nature of the disinfection byproducts (DBPs) is a direct function of the chemical nature of the disinfectant itself and/or of the chemical reactions of the disinfectant with reaction substrates in the water, especially organic constituents. A principal advantage of biological and physical water treatment processes, such as filtration, is the lack of chemical reactions producing disinfectant-related DBPs. The use of the highest quality source water available is important for minimization of DBP formation. In lieu of such high quality water, improvement of water quality by removal of DBP precursors through filtration or other means before application of chemical disinfectants is important. Most, if not all, water treatment experts are aware of these simplistic axioms. In view of the increasing knowledge being developed concerning DBPs including the identification of new'' DBPs, prudence dictates minimization of DBP formation. Wholesome drinking water is perhaps the biggest economic bargain available to consumers. The cost-effectiveness of water quality improvement should be evaluated with that in mind.

  16. Application of solar energy to air conditioning systems

    NASA Technical Reports Server (NTRS)

    Nash, J. M.; Harstad, A. J.

    1976-01-01

    The results of a survey of solar energy system applications of air conditioning are summarized. Techniques discussed are both solar powered (absorption cycle and the heat engine/Rankine cycle) and solar related (heat pump). Brief descriptions of the physical implications of various air conditioning techniques, discussions of status, proposed technological improvements, methods of utilization and simulation models are presented, along with an extensive bibliography of related literature.

  17. Performance of air sparging systems: a review of case studies.

    PubMed

    Bass, D H; Hastings, N A; Brown, R A

    2000-02-25

    Fluor Daniel GTI (now IT Corporation) has compiled a database of 49 completed in-situ air sparging case studies. Air sparging is a commonly used remediation technology which volatilizes and enhances aerobic biodegradation of contamination in groundwater and saturated zone soil. The air sparging database was compiled to address questions regarding the effectiveness and permanence of air sparging, and to provide predictive indicators of air sparging success to aid in optimization of existing and future air sparging systems. In each case study, groundwater concentrations were compared before sparging was initiated, just before sparging was terminated, and in the months following shutdown of the sparging system. The case studies included both chlorinated solvents and petroleum hydrocarbon contamination, and covered a wide range of soil conditions and sparge system parameters. In many cases, air sparging achieved a substantial and permanent decrease in groundwater concentrations. Successful systems were achieved with both chlorinated and petroleum contamination, both sandy and silty soils, and both continuous and pulsed flow sparging. In other cases, however, a significant rebound of groundwater concentrations was observed after sparging was terminated. Rebound sometimes required 6 to 12 months to develop fully. Rebound was more frequently observed at sites contaminated with petroleum hydrocarbons than with chlorinated solvents. Petroleum-contaminated sites were more likely to rebound when initial groundwater contamination levels were high enough to suggest the presence of LNAPL or a smear zone of residual LNAPL. Rebound at petroleum sites appeared to be minimized by a high density of sparge wells addressing the entire source area and a high sparge air injection rate. In some cases, rebound appeared to be related to a rising water table.

  18. Resistance of Pseudomonas aeruginosa Isolates to Hydrogel Contact Lens Disinfection Correlates with Cytotoxic Activity

    PubMed Central

    Lakkis, Carol; Fleiszig, Suzanne M. J.

    2001-01-01

    One of the most common pathogens in infection of hydrogel contact lens wearers is Pseudomonas aeruginosa, which can gain access to the eye via contamination of the lens, lens case, and lens care solutions. Only one strain per species is used in current regulatory testing for the marketing of chemical contact lens disinfectants. The aim of this study was to determine whether P. aeruginosa strains vary in their susceptibility to hydrogel contact lens disinfectants. A method for rapidly screening bacterial susceptibility to contact lens disinfectants was developed, based on measurement of the MIC. The susceptibility of 35 P. aeruginosa isolates to two chemical disinfectants was found to vary among strains. MICs ranged from 6.25 to 100% for both disinfectants at 37°C, and a number of strains were not inhibited by a 100% disinfectant concentration in the lens case environment at room temperature (22°C). Resistance to disinfection appeared to be an inherent rather than acquired trait, since some resistant strains had been isolated prior to the introduction of the disinfectants and some susceptible P. aeruginosa strains could not be made more resistant by repeated disinfectant exposure. A number of P. aeruginosa strains which were comparatively more resistant to short-term disinfectant exposure also demonstrated the ability to grow to levels above the initial inoculum in one chemical disinfectant after long-term (24 to 48 h) disinfectant exposure. Resistance was correlated with acute cytotoxic activity toward corneal epithelial cells and with exsA, which encodes a protein that regulates cytotoxicity via a complex type III secretion system. These results suggest that chemical disinfection solutions may select for contamination with cytotoxic strains. Further investigation of the mechanisms and factors responsible for resistance may also lead to strategies for reducing adverse responses to contact lens wear. PMID:11283074

  19. Integrated Collision Avoidance System for Air Vehicle

    NASA Technical Reports Server (NTRS)

    Lin, Ching-Fang (Inventor)

    2013-01-01

    Collision with ground/water/terrain and midair obstacles is one of the common causes of severe aircraft accidents. The various data from the coremicro AHRS/INS/GPS Integration Unit, terrain data base, and object detection sensors are processed to produce collision warning audio/visual messages and collision detection and avoidance of terrain and obstacles through generation of guidance commands in a closed-loop system. The vision sensors provide more information for the Integrated System, such as, terrain recognition and ranging of terrain and obstacles, which plays an important role to the improvement of the Integrated Collision Avoidance System.

  20. Artificial immune system approach for air combat maneuvering

    NASA Astrophysics Data System (ADS)

    Kaneshige, John; Krishnakumar, Kalmanje

    2007-04-01

    Since future air combat missions will involve both manned and unmanned aircraft, the primary motivation for this research is to enable unmanned aircraft with intelligent maneuvering capabilities. During air combat maneuvering, pilots use their knowledge and experience of maneuvering strategies and tactics to determine the best course of action. As a result, we try to capture these aspects using an artificial immune system approach. The biological immune system protects the body against intruders by recognizing and destroying harmful cells or molecules. It can be thought of as a robust adaptive system that is capable of dealing with an enormous variety of disturbances and uncertainties. However, another critical aspect of the immune system is that it can remember how previous encounters were successfully defeated. As a result, it can respond faster to similar encounters in the future. This paper describes how an artificial immune system is used to select and construct air combat maneuvers. These maneuvers are composed of autopilot mode and target commands, which represent the low-level building blocks of the parameterized system. The resulting command sequences are sent to a tactical autopilot system, which has been enhanced with additional modes and an aggressiveness factor for enabling high performance maneuvers. Just as vaccinations train the biological immune system how to combat intruders, training sets are used to teach the maneuvering system how to respond to different enemy aircraft situations. Simulation results are presented, which demonstrate the potential of using immunized maneuver selection for the purposes of air combat maneuvering.

  1. A radome for air traffic control SSR radar systems

    NASA Astrophysics Data System (ADS)

    A new generation of monopulse and discrete interrogation systems has evolved for air traffic control applications that presents significant challenges to total system design and performance. Reliable operation of the antenna system is essential in today's ever increasing air traffic congestion. An important component of the total system is a radome to protect the antenna from the environment and to enable consistent, reliable electromagnetic performance. The various types of radomes that have been employed over the years to protect antennas are discussed and evaluated relative to the air traffic control radar application. The sandwich radome is selected as the best option and a detailed design analysis is presented which considers the vital characteristics of transmissivity, boresight error, and sidelobe perturbations.

  2. Infrared Laser System for Extended Area Monitoring of Air Pollution

    NASA Technical Reports Server (NTRS)

    Snowman, L. R.; Gillmeister, R. J.

    1971-01-01

    An atmospheric pollution monitoring system using a spectrally scanning laser has been developed by the General Electric Company. This paper will report on an evaluation of a breadboard model, and will discuss applications of the concept to various ambient air monitoring situations. The system is adaptable to other tunable lasers. Operating in the middle infrared region, the system uses retroreflectors to measure average concentrations over long paths at low, safe power levels. The concept shows promise of meeting operational needs in ambient air monitoring and providing new data for atmospheric research.

  3. One-man electrochemical air revitalization system evaluation

    NASA Technical Reports Server (NTRS)

    Schbert, F. H.; Marshall, R. D.; Hallick, T. M.; Woods, R. R.

    1976-01-01

    A program to evaluate the performance of a one man capacity, self contained electrochemical air revitalization system was successfully completed. The technology readiness of this concept was demonstrated by characterizing the performance of this one man system over wide ranges in cabin atmospheric conditions. The electrochemical air revitalization system consists of a water vapor electrolysis module to generate oxygen from water vapor in the cabin air, and an electrochemical depolarized carbon dioxide concentrator module to remove carbon dioxide from the cabin air. A control/monitor instrumentation package that uses the electrochemical depolarized concentrator module power generated to partially offset the water vapor electrolysis module power requirements and various structural fluid routing components are also part of the system. The system was designed to meet the one man metabolic oxygen generation and carbon dioxide removal requirements, thereby controlling cabin partial pressure of oxygen at 22 kN/sq m and cabin pressure of carbon dioxide at 400 N/sq m over a wide range in cabin air relative humidity conditions.

  4. Hydrogen-air energy storage gas-turbine system

    NASA Astrophysics Data System (ADS)

    Schastlivtsev, A. I.; Nazarova, O. V.

    2016-02-01

    A hydrogen-air energy storage gas-turbine unit is considered that can be used in both nuclear and centralized power industries. However, it is the most promising when used for power-generating plants based on renewable energy sources (RES). The basic feature of the energy storage system in question is combination of storing the energy in compressed air and hydrogen and oxygen produced by the water electrolysis. Such a process makes the energy storage more flexible, in particular, when applied to RES-based power-generating plants whose generation of power may considerably vary during the course of a day, and also reduces the specific cost of the system by decreasing the required volume of the reservoir. This will allow construction of such systems in any areas independent of the local topography in contrast to the compressed-air energy storage gas-turbine plants, which require large-sized underground reservoirs. It should be noted that, during the energy recovery, the air that arrives from the reservoir is heated by combustion of hydrogen in oxygen, which results in the gas-turbine exhaust gases practically free of substances hazardous to the health and the environment. The results of analysis of a hydrogen-air energy storage gas-turbine system are presented. Its layout and the principle of its operation are described and the basic parameters are computed. The units of the system are analyzed and their costs are assessed; the recovery factor is estimated at more than 60%. According to the obtained results, almost all main components of the hydrogen-air energy storage gas-turbine system are well known at present; therefore, no considerable R&D costs are required. A new component of the system is the H2-O2 combustion chamber; a difficulty in manufacturing it is the necessity of ensuring the combustion of hydrogen in oxygen as complete as possible and preventing formation of nitric oxides.

  5. Regenerable Air Purification System for Gas-Phase Contaminant Control

    NASA Technical Reports Server (NTRS)

    Constantinescu, Ileana C.; Finn, John E.; LeVan, M. Douglas; Lung, Bernadette (Technical Monitor)

    2000-01-01

    Tests of a pre-prototype regenerable air purification system (RAPS) that uses water vapor to displace adsorbed contaminants from an adsorbent column have been performed at NASA Ames Research Center. A unit based on this design can be used for removing trace gas-phase contaminants from spacecraft cabin air or from polluted process streams including incinerator exhaust. During the normal operation mode, contaminants are removed from the air on the column. Regeneration of the column is performed on-line. During regeneration, contaminants are displaced and destroyed inside the closed oxidation loop. In this presentation we discuss initial experimental results for the performance of RAPS in the removal and treatment of several important spacecraft contaminant species from air.

  6. Effect of well disinfection on arsenic in ground water

    USGS Publications Warehouse

    Gotkowitz, M.; Ellickson, K.; Clary, A.; Bowman, G.; Standridge, J.; Sonzogni, W.

    2008-01-01

    Domestic water wells are routinely subjected to in situ chemical disinfection treatments to control nuisance or pathogenic bacteria. Most treatments are chlorine based and presumably cause strongly oxidizing conditions in the wellbore. Water resource managers in Wisconsin were concerned that such treatments might facilitate release of arsenic from sulfide minerals disseminated within a confined sandstone aquifer. To test this hypothesis, a well was subjected to four disinfection treatments over 9 months time. The first treatment consisted of routine pumping of the well without chemical disinfection; three subsequent treatments included chlorine disinfection and pumping. Pretreatment arsenic concentrations in well water ranged from 7.4 to 18 ??g/L. Elevated arsenic concentrations up to 57 ??g/L in the chemical treatment solutions purged from the well are attributed to the disintegration or dissolution of biofilms or scale. Following each of the four treatments, arsenic concentrations decreased to less than 10 ??g/L during a period of pumping. Arsenic concentrations generally returned to pretreatment levels under stagnant, nonpumping conditions imposed following each treatment. Populations of iron-oxidizing, heterotrophic, and sulfate-reducing bacteria decreased following chemical treatments but were never fully eradicated from the well. Strongly oxidizing conditions were induced by the chlorine-based disinfections, but the treatments did not result in sustained increases in well water arsenic. Results suggest that disruption of biofilm and mineral deposits in the well and the water distribution system in tandem with chlorine disinfection can improve water quality in this setting. ?? 2008 The Author(s).

  7. Dental unit waterlines disinfection using hypochlorous acid-based disinfectant

    PubMed Central

    Shajahan, Irfana Fathima; Kandaswamy, D; Srikanth, Padma; Narayana, L Lakshmi; Selvarajan, R

    2016-01-01

    Objective: The purpose of the study was to investigate the efficacy of a new disinfectant to disinfect the dental unit waterlines. Materials and Methods: New dental unit waterlines were installed in 13 dental chairs, and biofilm was allowed to grow for 10 days. Disinfection treatment procedure was carried out in the 12 units, and one unit was left untreated. The dental unit waterlines were removed and analyzed using the scanning electron microscope (SEM) (TESCAN VEGA3 SBU). Result: On examination, SEM images showed that there was no slime layer or bacterial cells seen in any of the 12 cut sections obtained from the treated dental waterlines which mean that there was no evident of biofilm formation. Untreated dental unit waterlines showed a microbial colonization with continuous filamentous organic matrix. There was significant biofilm formation in the control tube relative to the samples. Conclusion: The tested disinfectant was found to be effective in the removal of biofilm from the dental unit waterlines. PMID:27563184

  8. Compressed Air System Optimization: Case Study Food Industry in Indonesia

    NASA Astrophysics Data System (ADS)

    Widayati, Endang; Nuzahar, Hasril

    2016-01-01

    Compressors and compressed air systems was one of the most important utilities in industries or factories. Approximately 10% of the cost of electricity in the industry was used to produce compressed air. Therefore the potential for energy savings in the compressors and compressed air systems had a big challenge. This field was conducted especially in Indonesia food industry or factory. Compressed air system optimization was a technique approach to determine the optimal conditions for the operation of compressors and compressed air systems that included evaluation of the energy needs, supply adjustment, eliminating or reconfiguring the use and operation of inefficient, changing and complementing some equipment and improving operating efficiencies. This technique gave the significant impact for energy saving and costs. The potential savings based on this study through measurement and optimization e.g. system that lowers the pressure of 7.5 barg to 6.8 barg would reduce energy consumption and running costs approximately 4.2%, switch off the compressor GA110 and GA75 was obtained annual savings of USD 52,947 ≈ 455 714 kWh, running GA75 light load or unloaded then obtained annual savings of USD 31,841≈ 270,685 kWh, install new compressor 2x132 kW and 1x 132 kW VSD obtained annual savings of USD 108,325≈ 928,500 kWh. Furthermore it was needed to conduct study of technical aspect of energy saving potential (Investment Grade Audit) and performed Cost Benefit Analysis. This study was one of best practice solutions how to save energy and improve energy performance in compressors and compressed air system.

  9. New challenges to air/gas cleaning systems

    SciTech Connect

    Kovach, J.L.

    1997-08-01

    This paper discusses the need for changes in the design and manufacturing of air and gas cleaning systems to meet waste management and site remediation requirements. Current design and manufacturing practices are primarily directed toward evaluating operational problems with existing systems in nuclear reactor facilities. However, nuclear waste management needs have developed which are much broader in scope and have different processing conditions. Numerous examples of air cleaning needs for waste management activities are provided; the major differences from operating facility needs are the requirement for continuous effluent treatment under widely different processing conditions. Related regulatory issues are also discussed briefly. 1 ref.

  10. Low power, constant-flow air pump systems

    SciTech Connect

    Polito, M.D.; Albert, B.

    1994-01-01

    A rugged, yet small and lightweight constant-flow air pump system has been designed. Flow control is achieved using a novel approach which is three times more power efficient than previous designs. The resultant savings in battery size and weight makes these pumps ideal for sampling air on balloon platforms. The pump package includes meteorological sensors and an onboard computer that stores time and sensor data and turns the constant-flow pump circuit on/off. Some applications of these systems are also presented in this report.

  11. Measured Air Distribution Effectiveness for Residential Mechanical Ventilation Systems

    SciTech Connect

    Sherman, Max; Sherman, Max H.; Walker, Iain S.

    2008-05-01

    The purpose of ventilation is dilute or remove indoor contaminants that an occupant is exposed to. In a multi-zone environment such as a house, there will be different dilution rates and different source strengths in every zone. Most US homes have central HVAC systems, which tend to mix the air thus the indoor conditions between zones. Different types of ventilation systems will provide different amounts of exposure depending on the effectiveness of their air distribution systems and the location of sources and occupants. This paper will report on field measurements using a unique multi-tracer measurement system that has the capacity to measure not only the flow of outdoor air to each zone, but zone-to-zone transport. The paper will derive seven different metrics for the evaluation of air distribution. Measured data from two homes with different levels of natural infiltration will be used to evaluate these metrics for three different ASHRAE Standard 62.2 compliant ventilation systems. Such information can be used to determine the effectiveness of different systems so that appropriate adjustments can be made in residential ventilation standards such as ASHRAE Standard 62.2.

  12. [First results on the use of chloramines to reduce disinfection byproducts in drinking water].

    PubMed

    Azara, Antonio; Muresu, Elena; Dettori, Marco; Ciappeddu, Pierluigi; Deidda, Antonio; Maida, Alessandro

    2010-01-01

    The presence of disinfection byproducts (DBP) in drinking water raises concerns about the safety of chlorination and is one of the problems inherent the use of surface water as a source of drinking water. In order to reduce the presence of DBP (in particular of chlorites), we evaluated the combined use of chlorine dioxide for primary disinfection and monochloramine for residual disinfection in a water purification plant and distribution system in Sardinia (Italy). The results are very encouraging. Disinfection byproducts were reduced and other parameters were found to be within the recommended standards, indicating further improvements of the purification process.

  13. Air Cleaning Devices for HVAC Supply Systems in Schools. Technical Bulletin.

    ERIC Educational Resources Information Center

    Wheeler, Arthur E.

    Guidelines for maintaining indoor air quality in schools with HVAC air cleaning systems are provided in this document. Information is offered on the importance of air cleaning, sources of air contaminants and indoor pollutants, types of air cleaners and particulate filters used in central HVAC systems, vapor and gas removal, and performance…

  14. Comparing irradiation parameters on disinfecting enterrecoccus faecalis in root canal disinfection

    NASA Astrophysics Data System (ADS)

    Sarp, Ayşe. S.; Gülsoy, Murat

    2016-02-01

    Although conventional method carries all the debris, studies on persisting infections in root canals show bacteria and their toxins spread from the root canal and contaminate the apical region. Thus developes apical periodontitis or symptoms, and loss of tooth. Even if the treatment has adequate success, anatomy of root canal system can be very complexwith accessory canals. The disinfecting effect of laser radiation has only recently been used in dentistry. Laser irradiation has a bactericidal effect. Each wavelength has its own advantages and limitations according to their different absorption characteristics, depending on their 'absorption coefficient'. The sterilizing efficiency of two types of wavelengths, a new fiber laser 1940- nm Thulium fiber Laser and an 2940 nm Er:YAG Laser were compared in this study. Irradiation with a power of 0.50 W with 1940- nm Thulium fiber Laser disinfected 95,15% of bacteria, however irradiation with same laser power with Er:YAG Laser caused a reduction of 96,48 %. But there was no significant difference in the disinfection effect of two different laser groups ( p < 0.05, Mann- U-Whitney Test). In addition to this, Er :YAG Laser caused three times more reduction from its own positive control group where 1940- nm Thulium fiber Laser caused 2,5 times effective disinfection.

  15. HESTIA Phase I Test Results: The Air Revitalization System

    NASA Technical Reports Server (NTRS)

    Wright, Sarah E.; Hansen, Scott W.

    2016-01-01

    In any human spaceflight mission, a number of Environmental Control & Life Support System (ECLSS) technologies work together to provide the conditions astronauts need to live healthily, productively, and comfortably in space. In a long-duration mission, many of these ECLSS technologies may use materials supplied by In-Situ Resource Utilization (ISRU), introducing more interactions between systems. The Human Exploration Spacecraft Test-bed for Integration & Advancement (HESTIA) Project aims to create a test-bed to evaluate ECLSS and ISRU technologies and how they interact in a high-fidelity, closed-loop, human-rated analog habitat. Air purity and conditioning are essential components within any ECLSS and for HESTIA's first test they were achieved with the Air Revitalization System (ARS) described below. The ARS provided four essential functions to the test-bed chamber: cooling the air, removing humidity from the air, removing trace contaminants, and scrubbing carbon dioxide (CO2) from the air. In this case, the oxygen supply function was provided by ISRU. In the current configuration, the ARS is a collection of different subsystems. A fan circulates the air, while a condensing heat exchanger (CHX) pulls humidity out of the air. A Trace Contaminant Removal System (TCRS) filters the air of potentially harmful contaminants. Lastly, a Reactive Plastic Lithium Hydroxide (RP-LiOH) unit removes CO2 from the breathing air. During the HESTIA Phase I test in September 2015, the ARS and its individual components each functioned as expected, although further analysis is underway. During the Phase I testing and in prior bench-top tests, the energy balance of heat removed by the CHX was not equal to the cooling it received. This indicated possible instrument error and therefore recalibration of the instruments and follow-up testing is planned in 2016 to address the issue. The ARS was tested in conjunction with two other systems: the Human Metabolic Simulator (HMS) and the

  16. Air Purification in Closed Environments: An Overview of Spacecraft Systems

    NASA Technical Reports Server (NTRS)

    Perry, Jay L.; LeVan, Douglas; Crumbley, Robert (Technical Monitor)

    2002-01-01

    The primary goal for a collective protection system and a spacecraft environmental control and life support system (ECLSS) are strikingly similar. Essentially both function to provide the occupants of a building or vehicle with a safe, habitable environment. The collective protection system shields military and civilian personnel from short-term exposure to external threats presented by toxic agents and industrial chemicals while an ECLSS sustains astronauts for extended periods within the hostile environment of space. Both have air quality control similarities with various aircraft and 'tight' buildings. This paper reviews basic similarities between air purification system requirements for collective protection and an ECLSS that define surprisingly common technological challenges and solutions. Systems developed for air revitalization on board spacecraft are discussed along with some history on their early development as well as a view of future needs. Emphasis is placed upon two systems implemented by the National Aeronautics and Space Administration (NASA) onboard the International Space Station (ISS): the trace contaminant control system (TCCS) and the molecular sieve-based carbon dioxide removal assembly (CDRA). Over its history, the NASA has developed and implemented many life support systems for astronauts. As the duration, complexity, and crew size of manned missions increased from minutes or hours for a single astronaut during Project Mercury to days and ultimately months for crews of 3 or more during the Apollo, Skylab, Shuttle, and ISS programs, these systems have become more sophisticated. Systems aboard spacecraft such as the ISS have been designed to provide long-term environmental control and life support. Challenges facing the NASA's efforts include minimizing mass, volume, and power for such systems, while maximizing their safety, reliability, and performance. This paper will highlight similarities and differences among air purification systems

  17. Hollow Fiber Membrane Dehumidification Device for Air Conditioning System.

    PubMed

    Zhao, Baiwang; Peng, Na; Liang, Canzeng; Yong, Wai Fen; Chung, Tai-Shung

    2015-01-01

    In order to provide a comfortable living and working environment indoors in tropical countries, the outdoor air often needs to be cooled and dehumidified before it enters the rooms. Membrane separation is an emerging technology for air dehumidification and it is based on the solution diffusion mechanism. Water molecules are preferentially permeating through the membranes due to its smaller kinetic diameter and higher condensability than the other gases. Compared to other dehumidification technologies such as direct cooling or desiccation, there is no phase transition involved in membrane dehumidification, neither the contact between the fresh air stream and the desiccants. Hence, membrane dehumidification would not only require less energy consumption but also avoid cross-contamination problems. A pilot scale air dehumidification system is built in this study which comprises nine pieces of one-inch PAN/PDMS hollow fiber membrane modules. A 150 h long-term test shows that the membrane modules has good water vapor transport properties by using a low vacuum force of only 0.78 bar absolute pressure at the lumen side. The water vapor concentration of the feed humid air decreases dramatically from a range of 18-22 g/m³ to a range of 13.5-18.3 g/m³. Most importantly, the total energy saving is up to 26.2% compared with the conventional air conditioning process. PMID:26580660

  18. Hollow Fiber Membrane Dehumidification Device for Air Conditioning System.

    PubMed

    Zhao, Baiwang; Peng, Na; Liang, Canzeng; Yong, Wai Fen; Chung, Tai-Shung

    2015-11-16

    In order to provide a comfortable living and working environment indoors in tropical countries, the outdoor air often needs to be cooled and dehumidified before it enters the rooms. Membrane separation is an emerging technology for air dehumidification and it is based on the solution diffusion mechanism. Water molecules are preferentially permeating through the membranes due to its smaller kinetic diameter and higher condensability than the other gases. Compared to other dehumidification technologies such as direct cooling or desiccation, there is no phase transition involved in membrane dehumidification, neither the contact between the fresh air stream and the desiccants. Hence, membrane dehumidification would not only require less energy consumption but also avoid cross-contamination problems. A pilot scale air dehumidification system is built in this study which comprises nine pieces of one-inch PAN/PDMS hollow fiber membrane modules. A 150 h long-term test shows that the membrane modules has good water vapor transport properties by using a low vacuum force of only 0.78 bar absolute pressure at the lumen side. The water vapor concentration of the feed humid air decreases dramatically from a range of 18-22 g/m³ to a range of 13.5-18.3 g/m³. Most importantly, the total energy saving is up to 26.2% compared with the conventional air conditioning process.

  19. Hollow Fiber Membrane Dehumidification Device for Air Conditioning System

    PubMed Central

    Zhao, Baiwang; Peng, Na; Liang, Canzeng; Yong, Wai Fen; Chung, Tai-Shung

    2015-01-01

    In order to provide a comfortable living and working environment indoors in tropical countries, the outdoor air often needs to be cooled and dehumidified before it enters the rooms. Membrane separation is an emerging technology for air dehumidification and it is based on the solution diffusion mechanism. Water molecules are preferentially permeating through the membranes due to its smaller kinetic diameter and higher condensability than the other gases. Compared to other dehumidification technologies such as direct cooling or desiccation, there is no phase transition involved in membrane dehumidification, neither the contact between the fresh air stream and the desiccants. Hence, membrane dehumidification would not only require less energy consumption but also avoid cross-contamination problems. A pilot scale air dehumidification system is built in this study which comprises nine pieces of one-inch PAN/PDMS hollow fiber membrane modules. A 150 h long-term test shows that the membrane modules has good water vapor transport properties by using a low vacuum force of only 0.78 bar absolute pressure at the lumen side. The water vapor concentration of the feed humid air decreases dramatically from a range of 18–22 g/m3 to a range of 13.5–18.3 g/m3. Most importantly, the total energy saving is up to 26.2% compared with the conventional air conditioning process. PMID:26580660

  20. The effect of UV/H2O2 treatment on disinfection by-product formation potential under simulated distribution system conditions.

    PubMed

    Metz, D H; Meyer, M; Dotson, A; Beerendonk, E; Dionysiou, D D

    2011-07-01

    Advanced oxidation with ultraviolet light and hydrogen peroxide (UV/H(2)O(2)) produces hydroxyl radicals that have the potential to degrade a wide-range of organic micro-pollutants in water. Yet, when this technology is used to reduce target contaminants, natural organic matter can be altered. This study evaluated disinfection by-product (DBP) precursor formation for UV/H(2)O(2) while reducing trace organic contaminants in natural water (>90% for target pharmaceuticals, pesticides and taste and odor producing compounds and 80% atrazine degradation). A year-long UV/H(2)O(2) pilot study was conducted to evaluate DBP precursor formation with varying water quality. The UV pilot reactors were operated to consistently achieve 80% atrazine degradation, allowing comparison of low pressure (LP) and medium pressure (MP) lamp technologies for DBP precursor formation. Two process waters of differing quality were used as pilot influent, i.e., before and after granular activated carbon adsorption. DBP precursors increased under most of the conditions studied. Regulated trihalomethane formation potential increased through the UV/H(2)O(2) reactors from 20 to 118%, depending on temperature and water quality. When Post-GAC water served as reactor influent, less DBPs were produced in comparison to conventionally treated water. Haloacetic acid (HAA5) increased when conventionally treated water served as UV/H(2)O(2) pilot influent, but only increased slightly (MP lamp) when GAC treated water served as pilot influent. No difference in 3-day simulated distribution system DBP concentration was observed between LP and MP UV reactors when 80% atrazine degradation was targeted.

  1. TEWI Evaluation for Household Refrigeration and Air-Conditioning Systems

    NASA Astrophysics Data System (ADS)

    Sobue, Atsushi; Watanabe, Koichi

    In the present study, we have quantitatively evaluated the global warming impact by household refrigerator and air-conditioning systems on the basis of reliable TEWI information. In TEWI evaluation of household refrigerators, the percentage of the impact by refrigerant released to the atmosphere (direct effect) is less than 18.6% in TEWI. In case of room air-conditioners, however, the percentage of direct effect is less than 5.4% in TEWI. Therefore, it was confirmed that impact by CO2 released as a result of the energy consumed to drive the refrigeration or air-conditioning systems throughout their lifetime (indirect effect) is far larger than direct effect by the entire system. A reduction of indirect effect by energy saving is the most effective measure in reducing the global warming impact by refrigeration and air-conditioning systems, For a realization of the energy saving, not only the advanced improvement in energy efficiency by household appliance manufacturers but also the improvement of consumer's mind in selecting the systems and a way of using are concluded important.

  2. Improved fireman's compressed air breathing system pressure vessel development program

    NASA Technical Reports Server (NTRS)

    King, H. A.; Morris, E. E.

    1973-01-01

    Prototype high pressure glass filament-wound, aluminum-lined pressurant vessels suitable for use in a fireman's compressed air breathing system were designed, fabricated, and acceptance tested in order to demonstrate the feasibility of producing such high performance, lightweight units. The 4000 psi tanks have a 60 standard cubic foot (SCF) air capacity, and have a 6.5 inch diamter, 19 inch length, 415 inch volume, weigh 13 pounds when empty, and contain 33 percent more air than the current 45 SCF (2250 psi) steel units. The current steel 60 SCF (3000 psi) tanks weigh approximately twice as much as the prototype when empty, and are 2 inches, or 10 percent shorter. The prototype units also have non-rusting aluminum interiors, which removes the hazard of corrosion, the need for internal coatings, and the possibility of rust particles clogging the breathing system.

  3. Prototype Systems for Measuring Outdoor Air Intake Rates in Rooftop Air Handlers

    SciTech Connect

    Fisk, William J.; Chan, Wanyu R.; Hotchi, Toshifumi

    2015-01-01

    The widespread absence of systems for real-time measurement and feedback control, of minimum outdoor air intake rates in HVAC systems contributes to the poor control of ventilation rates in commercial buildings. Ventilation rates affect building energy consumption and influence occupant health. The project designed fabricated and tested four prototypes of systems for measuring rates of outdoor air intake into roof top air handlers. All prototypes met the ±20% accuracy target at low wind speeds, with all prototypes accurate within approximately ±10% after application of calibration equations. One prototype met the accuracy target without a calibration. With two of four prototype measurement systems, there was no evidence that wind speed or direction affected accuracy; however, winds speeds were generally below usually 3.5 m s-1 (12.6 km h-1) and further testing is desirable. The airflow resistance of the prototypes was generally less than 35 Pa at maximum RTU air flow rates. A pressure drop of this magnitude will increase fan energy consumption by approximately 4%. The project did not have resources necessary to estimate costs of mass produced systems. The retail cost of components and materials used to construct prototypes ranged from approximately $1,200 to $1,700. The test data indicate that the basic designs developed in this project, particularly the designs of two of the prototypes, have considerable merit. Further design refinement, testing, and cost analysis would be necessary to fully assess commercial potential. The designs and test results will be communicated to the HVAC manufacturing community.

  4. Novel air-based system transfers large salmon during harvest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In April of 2015, near the end of our last harvest of 4-6 kg Atlantic salmon, we evaluated an exciting new fish transport technology from Whooshh Innovations (Bellevue, WA) that uses air to move live Atlantic salmon from our growout tank to a finishing/purging tank. The Whooshh system uses a combina...

  5. New Compressor Added to Glenn's 450- psig Combustion Air System

    NASA Technical Reports Server (NTRS)

    Swan, Jeffrey A.

    2000-01-01

    In September 1999, the Central Process Systems Engineering Branch and the Maintenance and the Central Process Systems Operations Branch, released for service a new high pressure compressor to supplement the 450-psig Combustion Air System at the NASA Glenn Research Center at Lewis Field. The new compressor, designated C-18, is located in Glenn s Central Air Equipment Building and is remotely operated from the Central Control Building. C-18 can provide 40 pounds per second (pps) of airflow at pressure to our research customers. This capability augments our existing system capacity (compressors C 4 at 38 pps and C-5 at 32 pps), which is generated from Glenn's Engine Research Building. The C-18 compressor was originally part of Glenn's 21-Inch Hypersonic Tunnel, which was transferred from the Jet Propulsion Laboratory to Glenn in the mid-1980's. With the investment of construction of facilities funding, the compressor was modified, new mechanical and electrical support equipment were purchased, and the unit was installed in the basement of the Central Air Equipment Building. After several weeks of checkout and troubleshooting, the new compressor was ready for long-term, reliable operations. With a total of 110 pps in airflow now available, Glenn is well positioned to support the high-pressure air test requirements of our research customers.

  6. Air Revitalization System Enables Excursions to the Stratosphere

    NASA Technical Reports Server (NTRS)

    2015-01-01

    Paragon Space Development Corporation, based in Tucson, Arizona has had a long history of collaboration with NASA, including developing a modular air purification system under the Commercial Crew Development Program, designed to support the commercial space sector. Using that device and other NASA technology, startup company World View is now gearing up to take customers on helium balloon rides to the stratosphere.

  7. Computational fluid dynamics for turbomachinery internal air systems.

    PubMed

    Chew, John W; Hills, Nicholas J

    2007-10-15

    Considerable progress in development and application of computational fluid dynamics (CFD) for aeroengine internal flow systems has been made in recent years. CFD is regularly used in industry for assessment of air systems, and the performance of CFD for basic axisymmetric rotor/rotor and stator/rotor disc cavities with radial throughflow is largely understood and documented. Incorporation of three-dimensional geometrical features and calculation of unsteady flows are becoming commonplace. Automation of CFD, coupling with thermal models of the solid components, and extension of CFD models to include both air system and main gas path flows are current areas of development. CFD is also being used as a research tool to investigate a number of flow phenomena that are not yet fully understood. These include buoyancy-affected flows in rotating cavities, rim seal flows and mixed air/oil flows. Large eddy simulation has shown considerable promise for the buoyancy-driven flows and its use for air system flows is expected to expand in the future.

  8. 15. VIEW OF THE SPECIAL SHROUDING AND AIR HANDLING SYSTEM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. VIEW OF THE SPECIAL SHROUDING AND AIR HANDLING SYSTEM USED IN BERYLLIUM PRODUCTION. (3/30/89) - Rocky Flats Plant, Non-Nuclear Production Facility, South of Cottonwood Avenue, west of Seventh Avenue & east of Building 460, Golden, Jefferson County, CO

  9. Experimental Air Pressure Tank Systems for Process Control Education

    ERIC Educational Resources Information Center

    Long, Christopher E.; Holland, Charles E.; Gatzke, Edward P.

    2006-01-01

    In process control education, particularly in the field of chemical engineering, there is an inherent need for industrially relevant hands-on apparatuses that enable one to bridge the gap between the theoretical content of coursework and real-world applications. At the University of South Carolina, two experimental air-pressure tank systems have…

  10. PHASE I PILOT AIR CONVEYANCE SYSTEM DESIGN, CLEANING, AND CHARACTERIZATION

    EPA Science Inventory

    The report gives results of a project to develop and refine surface and airborne contamination
    measurement techniques that can be used to evaluate air conveyance system (ACS) cleaning.
    (NOTE: ACS cleaning is advertized to homeowners as a service having a number of benefits...

  11. Chlorine disinfection of grey water for reuse: effect of organics and particles.

    PubMed

    Winward, Gideon P; Avery, Lisa M; Stephenson, Tom; Jefferson, Bruce

    2008-01-01

    Adequate disinfection of grey water prior to reuse is important to prevent the potential transmission of disease-causing microorganisms. Chlorine is a widely utilised disinfectant and as such is a leading contender for disinfection of grey water intended for reuse. This study examined the impact of organics and particles on chlorine disinfection of grey water, measured by total coliform inactivation. The efficacy of disinfection was most closely linked with particle size. Larger particles shielded total coliforms from inactivation and disinfection efficacy decreased with increasing particle size. Blending to extract particle-associated coliforms (PACs) following chlorine disinfection revealed that up to 91% of total coliforms in chlorinated grey water were particle associated. The organic concentration of grey water affected chlorine demand but did not influence the disinfection resistance of total coliforms when a free chlorine residual was maintained. Implications for urban water reuse are discussed and it is recommended that grey water treatment systems target suspended solids removal to ensure removal of PACs prior to disinfection.

  12. Air Quality Model System For The Vienna/bratislava Region

    NASA Astrophysics Data System (ADS)

    Krüger, B. C.; Schmittner, W.; Kromp-Kolb, H.

    A model system has been build up, consisting of the mesoscale meteorological fore- cast model MM5 and the chemical air-quality model CAMx. The coarse grid covers central Europe. By nesting, a spatial resolution of 3 km is reached for the core area, which includes the cities of Vienna (Austria) and Bratislava (Slovakia). In a first approach, the model system has been applied to a 6-day period in Febru- ary 1997, which was characterized by stagnant meteorological conditions. During this episode, primary pollutants like CO and NO2 have been compared with ambient mea- surements for the validation of the new model system. In the future it is foreseen to improve the spatial resolution, to apply the model system also for ozone and particulates, and to utilize it for a short-time forecast of air-quality parameters.

  13. Reduction of sound in ventilation and similar air distribution systems

    NASA Astrophysics Data System (ADS)

    1982-07-01

    This Data Item is available as part of the ESDU Sub-series on Fluid Mechanics Internal Flow. A means of estimating the attenuation of sound in lined plenum chambers and ducts, and through silencers of the types used in ventilation and air-conditioning systems is given. Data are provided in graphical or tabular form for the estimation of typical silencer insertion loss, airflow generated noise and pressure loss. Both rectangular splitter silencers and cylindrical silencers are considered. The data may be used in the initial design of a system or to investigate the appropriate remedial action for an installed air distribution system that is found to be too noisy. The location of silencers in the duct system is considered, and an example is given to illustrate the use of the data provided in the selection and sizing of a silencer for a particular application.

  14. Mathematical model of one-man air revitalization system

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A mathematical model was developed for simulating the steady state performance in electrochemical CO2 concentrators which utilize (NMe4)2 CO3 (aq.) electrolyte. This electrolyte, which accommodates a wide range of air relative humidity, is most suitable for one-man air revitalization systems. The model is based on the solution of coupled nonlinear ordinary differential equations derived from mass transport and rate equations for the processes which take place in the cell. The boundary conditions are obtained by solving the mass and energy transport equations. A shooting method is used to solve the differential equations.

  15. Closed loop air cooling system for combustion turbines

    DOEpatents

    Huber, D.J.; Briesch, M.S.

    1998-07-21

    Convective cooling of turbine hot parts using a closed loop system is disclosed. Preferably, the present invention is applied to cooling the hot parts of combustion turbine power plants, and the cooling provided permits an increase in the inlet temperature and the concomitant benefits of increased efficiency and output. In preferred embodiments, methods and apparatus are disclosed wherein air is removed from the combustion turbine compressor and delivered to passages internal to one or more of a combustor and turbine hot parts. The air cools the combustor and turbine hot parts via convection and heat is transferred through the surfaces of the combustor and turbine hot parts. 1 fig.

  16. Closed loop air cooling system for combustion turbines

    DOEpatents

    Huber, David John; Briesch, Michael Scot

    1998-01-01

    Convective cooling of turbine hot parts using a closed loop system is disclosed. Preferably, the present invention is applied to cooling the hot parts of combustion turbine power plants, and the cooling provided permits an increase in the inlet temperature and the concomitant benefits of increased efficiency and output. In preferred embodiments, methods and apparatus are disclosed wherein air is removed from the combustion turbine compressor and delivered to passages internal to one or more of a combustor and turbine hot parts. The air cools the combustor and turbine hot parts via convection and heat is transferred through the surfaces of the combustor and turbine hot parts.

  17. Developments in skirt systems for air cushion vehicles

    NASA Astrophysics Data System (ADS)

    Inch, Peter; Prentice, Mark E.; Lewis, Carol Jean

    The present evaluation of the development status of air-cushion vehicle (ACV) skirts emphasizes the materials employed, with a view to the formulation of materials-performance requirements for next-generation AVCs and, in particular, an 'air-cushion catamaran' surface-effect ship (SES). Attention is given to novel skirt-design features which furnish substantial savings in maintenance costs. The employment of extant test rig data and the use of CAD methods are discussed, and the features of a novel system for the direct fixing of a bow finger onto an SES structure are noted.

  18. CLASSIFICATION OF THE MGR SUBSURFACE COMPRESSED AIR SYSTEM

    SciTech Connect

    R. Garrett

    1999-08-31

    The purpose of this analysis is to document the Quality Assurance (QA) classification of the Monitored Geologic Repository (MGR) subsurface compressed air system structures, systems and components (SSCs) performed by the MGR Safety Assurance Department. This analysis also provides the basis for revision of YMP/90-55Q, Q-List (YMP 1998). The Q-List identifies those MGR SSCs subject to the requirements of DOE/RW-0333P, ''Quality Assurance Requirements and Description'' (QARD) (DOE 1998).

  19. CLASSIFICATION OF THE MGR SITE COMPRESSED AIR SYSTEM

    SciTech Connect

    J.A. Ziegler

    1999-08-31

    The purpose of this analysis is to document the Quality Assurance (QA) classification of the Monitored Geologic Repository (MGR) site compressed air system structures, systems and components (SSCs) performed by the MGR Safety Assurance Department. This analysis also provides the basis for revision of YMP/90-55Q, Q-List (YMP 1998). The Q-List identifies those MGR SSCs subject to the requirements of DOE/RW-0333P, ''Quality Assurance Requirements and Description'' (QARD) (DOE 1998).

  20. Reduction of pollutants and disinfection of industrial wastewater by an integrated system of copper electrocoagulation and electrochemically generated hydrogen peroxide.

    PubMed

    Barrera-Díaz, Carlos E; Frontana-Uribe, Bernardo A; Roa-Morales, Gabriela; Bilyeu, Bryan W

    2015-01-01

    The objective of this study was to evaluate the effect of copper electrocoagulation and hydrogen peroxide on COD, color, turbidity, and bacterial activity in a mixed industry wastewater. The integrated system of copper electrocoagulation and hydrogen peroxide is effective at reducing the organic and bacterial content of industrial wastewater. The copper electrocoagulation alone reduces COD by 56% in 30 min at pH 2.8, but the combined system reduces COD by 78%, biochemical oxygen demand (BOD5) by 81%, and color by 97% under the same conditions. Colloidal particles are flocculated effectively, as shown by the reduction of zeta potential and the 84% reduction in turbidity and 99% reduction in total solids. Additionally, the total coliforms, fecal coliforms, and bacteria are all reduced by 99%. The integrated system is effective and practical for the reduction of both organic and bacterial content in industrial wastewater.

  1. AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT II, MAINTAINING THE AIR SYSTEM--DETROIT DIESEL ENGINES.

    ERIC Educational Resources Information Center

    Human Engineering Inst., Cleveland, OH.

    THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATION AND MAINTENANCE OF THE DIESEL ENGINE AIR SYSTEM. TOPICS ARE (1) OPERATION AND FUNCTION, (2) AIR CLEANER, (3) AIR SHUT-DOWN HOUSING, (4) EXHAUST SYSTEM, (5) BLOWER, (6) TURBOCHARGER, AND (7) TROUBLE-SHOOTING TIPS ON THE AIR SYSTEM. THE MODULE CONSISTS OF A…

  2. Design and Implementation of Automatic Air Flow Rate Control System

    NASA Astrophysics Data System (ADS)

    Akbar, A.; Saputra, C.; Munir, M. M.; Khairurrijal

    2016-08-01

    Venturimeter is an apparatus that can be used to measure the air flow rate. In this experiment we designed a venturimeter which equipped with a valve that is used to control the air flow rate. The difference of pressure between the cross sections was measured with the differential pressure sensor GA 100-015WD which can calculate the difference of pressures from 0 to 3737.33 Pa. A 42M048C Z36 stepper motor was used to control the valve. The precision of this motor rotation is about 0.15 °. A Graphical User Interface (GUI) was developed to monitor and set the value of flow rate then an 8-bit microcontroller was used to process the control system In this experiment- the venturimeter has been examined to get the optimal parameter of controller. The results show that the controller can set the stable output air flow rate.

  3. An integrated regenerative air revitalization system for spacecraft

    NASA Technical Reports Server (NTRS)

    Noyes, G. P.; Heppner, D. B.; Schubert, F. H.; Quattrone, P. D.

    1982-01-01

    Progress towards development of an air revitalization system (ARS) for spacecraft breathable atmosphere regeneration is assessed, and a preliminary design for a one-person ARS is described. The ARS is considered a necessary component of any permanently manned orbital station, and studies have demonstrated that penalties for expendable air supplies justify an ARS for missions longer than 40 days. CO2 must be removed and O2 returned along with N2, which can be extracted from hydrazine, with the H2 component returning to the operation of the CO2 reduction subsystem. An experimental ARS (ARX-1) features a cabin humidity control unit, a CO2 concentrator, an air-cooled CO2 reduction reactor, an oxygen generator (electrolysis), the hydrazine N2 generator, and a water handling unit. A 120-day test demonstrated one-button startup and 480 hr operation in a normal mode.

  4. THE EMISSION PROCESSING SYSTEM FOR THE ETA/CMAQ AIR QUALITY FORECAST SYSTEM

    EPA Science Inventory

    NOAA and EPA have created an Air Quality Forecast (AQF) system. This AQF system links an adaptation of the EPA's Community Multiscale Air Quality Model with the 12 kilometer ETA model running operationally at NOAA's National Center for Environmental Predication (NCEP). One of th...

  5. Modern technologies for improving cleaning and disinfection of environmental surfaces in hospitals.

    PubMed

    Boyce, John M

    2016-01-01

    Experts agree that careful cleaning and disinfection of environmental surfaces are essential elements of effective infection prevention programs. However, traditional manual cleaning and disinfection practices in hospitals are often suboptimal. This is often due in part to a variety of personnel issues that many Environmental Services departments encounter. Failure to follow manufacturer's recommendations for disinfectant use and lack of antimicrobial activity of some disinfectants against healthcare-associated pathogens may also affect the efficacy of disinfection practices. Improved hydrogen peroxide-based liquid surface disinfectants and a combination product containing peracetic acid and hydrogen peroxide are effective alternatives to disinfectants currently in widespread use, and electrolyzed water (hypochlorous acid) and cold atmospheric pressure plasma show potential for use in hospitals. Creating "self-disinfecting" surfaces by coating medical equipment with metals such as copper or silver, or applying liquid compounds that have persistent antimicrobial activity surfaces are additional strategies that require further investigation. Newer "no-touch" (automated) decontamination technologies include aerosol and vaporized hydrogen peroxide, mobile devices that emit continuous ultraviolet (UV-C) light, a pulsed-xenon UV light system, and use of high-intensity narrow-spectrum (405 nm) light. These "no-touch" technologies have been shown to reduce bacterial contamination of surfaces. A micro-condensation hydrogen peroxide system has been associated in multiple studies with reductions in healthcare-associated colonization or infection, while there is more limited evidence of infection reduction by the pulsed-xenon system. A recently completed prospective, randomized controlled trial of continuous UV-C light should help determine the extent to which this technology can reduce healthcare-associated colonization and infections. In conclusion, continued efforts to

  6. Prefeasibility study on compressed air energy storage systems

    NASA Astrophysics Data System (ADS)

    Elmahgary, Y.; Peltola, E.; Sipilae, K.; Vaeaetaeinen, A.

    1991-08-01

    A prefeasibility study on compressed air energy storage (CALS) systems was launched in VTT in the course of the year 1990. The study was undertaken partly in the Laboratory of Electrical and Automation Engineering and partly in the Road, Traffic and Geotechnical Laboratory. Information on existing mines in Finland which could be used as storage caverns were collected (part 2). The costs of excavating rock caverns for compressed air storage and those for forming suitable storage caverns in existing mines were also estimated. This information was used in the first (and present) part of the report to calculate the economics of CAES. In the present part (part 1) of the study, an analysis of the different possible systems was given following a review of literature on CAES. This was followed by an economic analysis which comprised two separate systems. The first consisted of conventional oil fueled gas turbine plants provided with the CALS system. In the second system, wind turbines were used to run the compressors which are used in charging the compressed air storage cavern. The results of the current prefeasibility study confirmed the economic attractiveness of the CAES in the first system. Wind turbines still seem, however, to be too expensive to compete with coal power plants. More accurate and straight-forward results could be obtained only in a more comprehensive study.

  7. Calibration of NASA Turbulent Air Motion Measurement System

    NASA Technical Reports Server (NTRS)

    Barrick, John D. W.; Ritter, John A.; Watson, Catherine E.; Wynkoop, Mark W.; Quinn, John K.; Norfolk, Daniel R.

    1996-01-01

    A turbulent air motion measurement system (TAMMS) was integrated onboard the Lockheed 188 Electra airplane (designated NASA 429) based at the Wallops Flight Facility in support of the NASA role in global tropospheric research. The system provides air motion and turbulence measurements from an airborne platform which is capable of sampling tropospheric and planetary boundary-layer conditions. TAMMS consists of a gust probe with free-rotating vanes mounted on a 3.7-m epoxy-graphite composite nose boom, a high-resolution inertial navigation system (INS), and data acquisition system. A variation of the tower flyby method augmented with radar tracking was implemented for the calibration of static pressure position error and air temperature probe. Additional flight calibration maneuvers were performed remote from the tower in homogeneous atmospheric conditions. System hardware and instrumentation are described and the calibration procedures discussed. Calibration and flight results are presented to illustrate the overall ability of the system to determine the three-component ambient wind fields during straight and level flight conditions.

  8. Generation of ozone foam and its application for disinfection

    NASA Astrophysics Data System (ADS)

    Hiragaki, Keisuke; Ishimaru, Tomiya; Nakanishi, Masaru; Muraki, Ryouji; Nieda, Masanori; Yamabe, Chobei

    2015-07-01

    Generated ozone foam was applied to the disinfection of Pseudomonas fluorescens. The effect of disinfection has been confirmed experimentally and new equipment for the disinfection of hands using this ozone foam has been put on the market for the practical use. The ozone foam was produced in the foam generator after mixing the water including surfactant (30 mL/min) and air including ozone (1000 ppm = 2.14 g/m3 ~ 1600 ppm = 3.4 g/m3, 300 mL/min). The liquid-to-gas ratio is 100 L/m3. The concentration of dissolved ozone in the thin liquid films of the bubbles was about 3 mg/L which was measured by the chemical method of the KI absorption and titration of sodium thiosulfate solution. The disinfection test samples were prepared using the PET disk on which Pseudomonas fluorescens of its number of more than 108 were attached. Test sample was inserted into ozone foam set on the glass plate for one to 6 min. The survival rate log (N/N0 decreased with time and its value of about-2.6 (i.e., ~1/400) was obtained at 6 min (2 min × 3 times repeated). It was also confirmed that the ozone foam was useful for the disinfection of hands. For more effective disinfection (in case of taking a long time for foam melting), the ozone foam was broken by force and changed into ozone water by which the survival rate decreased ×4 (i.e., N/N0 = 1/10 000) at 4 ~ 6 min. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  9. Pulsed-Plasma Disinfection of Water Containing Escherichia coli

    NASA Astrophysics Data System (ADS)

    Satoh, Kohki; MacGregor, Scott J.; Anderson, John G.; Woolsey, Gerry A.; Fouracre, R. Anthony

    2007-03-01

    The disinfection of water containing the microorganism, Escherichia coli (E. coli) by exposure to a pulsed-discharge plasma generated above the water using a multineedle electrode (plasma-exposure treatment), and by sparging the off-gas of the pulsed plasma into the water (off-gas-sparging treatment), is performed in the ambient gases of air, oxygen, and nitrogen. For the off-gas-sparging treatment, bactericidal action is observed only when oxygen is used as the ambient gas, and ozone is found to generate the bactericidal action. For the plasma-exposure treatment, the density of E. coli bacteria decreases exponentially with plasma-exposure time for all the ambient gases. It may be concluded that the main contributors to E. coli inactivation are particle species produced by the pulsed plasma. For the ambient gases of air and nitrogen, the influence of acidification of the water in the system, as a result of pulsed-plasma exposure, may also contribute to the decay of E. coli density.

  10. Fungal colonization of air filters for use in heating, ventilating, and air conditioning (HVAC) systems.

    PubMed

    Simmons, R B; Crow, S A

    1995-01-01

    New and used cellulosic air filters for HVAC systems including those treated with antimicrobials were suspended in vessels with a range of relative humidities (55-99%) and containing non-sterile potting soil which stimulates fungal growth. Most filters yielded fungi prior to suspension in the chambers but only two of 14 nontreated filters demonstrated fungal colonization following use in HVAC systems. Filters treated with antimicrobials, particularly a phosphated amine complex, demonstrated markedly less fungal colonization than nontreated filters. In comparison with nontreated cellulosic filters, fungal colonization of antimicrobial-treated cellulosic filters was selective and delayed.

  11. EVALUATION OF ON-SITE CHLORINE GENERATORS FOR THE DISINFECTION OF DRINKING WATER

    EPA Science Inventory

    Public Water Systems (PWSs) routinely use various forms of chlorine as the disinfectant of choice for the treatment of drinking water. Chlorine is a popular choice because it is a very effective disinfectant, it is inexpensive, and it is widely available in various forms to suit...

  12. Numerical characterization of the hydrodynamics and thermal behavior of air flow in flexible air distribution system

    NASA Astrophysics Data System (ADS)

    Gharehdaghi, Samad; Moujaes, Samir

    2013-10-01

    Flexible duct air distribution systems are used in a large percentage of residential and small commercial buildings in the United States . Very few empirical or predictive data are available though to help provide the HVAC design engineer with reliable information . Moreover, because of the ducts flexibility, the shapes of these ducts offer a different set of operating fluid flow and thermal conditions from traditional smooth metal ducts. Hence, both the flow field and heat transfer through this kind of ducts are much more complex and merit to be analyzed from a numerical predictive approach. The aim of this research paper is to compute some of the hydrodynamic and heat transfer characteristics of the air flow inside these ducts over a range of Re numbers commonly used in the flow conditions of these air distribution systems. The information resulting from this CFD simulation, where a κ-ɛ turbulent model is used to predict the flow conditions, provide pressure drop and average convective heat transfer coefficients that exist in these ducts and was compared to previously found data. Circulation zones in the depressions of these ducts are found to exist which are suspected of influencing the pressured drop and heat transfer coefficients as compared to smooth ducts. The results show that fully developed conditions exist much earlier with regard to the inlet for both hydrodynamic and thermal entrance regions than what would be expected in smooth ducts under the same turbulent conditions.

  13. Air cargo: An Integrated Systems View. 1978 Summer Faculty Fellowship Program in Engineering Systems Design

    NASA Technical Reports Server (NTRS)

    Keaton, A. (Editor); Eastman, R. (Editor); Hargrove, A. (Editor); Rabiega, W. (Editor); Olsen, R. (Editor); Soberick, M. (Editor)

    1978-01-01

    The national air cargo system is analyzed and how it should be in 1990 is prescribed in order to operate successfully through 2015; that is through one equipment cycle. Elements of the system which are largely under control of the airlines and the aircraft manufacturers are discussed. The discussion deals with aircraft, networks, facilities, and procedures. The regulations which govern the movement of air freight are considered. The larger public policy interests which must be served by the kind of system proposed, the air cargo integrated system (ACIS), are addressed. The possible social, economical, political, and environment impacts of the system are considered. Recommendations are also given.

  14. Impact of Nitrification on the Formation of N-Nitrosamines and Halogenated Disinfection Byproducts within Distribution System Storage Facilities.

    PubMed

    Zeng, Teng; Mitch, William A

    2016-03-15

    Distribution system storage facilities are a critical, yet often overlooked, component of the urban water infrastructure. This study showed elevated concentrations of N-nitrosodimethylamine (NDMA), total N-nitrosamines (TONO), regulated trihalomethanes (THMs) and haloacetic acids (HAAs), 1,1-dichloropropanone (1,1-DCP), trichloroacetaldehyde (TCAL), haloacetonitriles (HANs), and haloacetamides (HAMs) in waters with ongoing nitrification as compared to non-nitrifying waters in storage facilities within five different chloraminated drinking water distribution systems. The concentrations of NDMA, TONO, HANs, and HAMs in the nitrifying waters further increased upon application of simulated distribution system chloramination. The addition of a nitrifying biofilm sample collected from a nitrifying facility to its non-nitrifying influent water led to increases in N-nitrosamine and halogenated DBP formation, suggesting the release of precursors from nitrifying biofilms. Periodic treatment of two nitrifying facilities with breakpoint chlorination (BPC) temporarily suppressed nitrification and reduced precursor levels for N-nitrosamines, HANs, and HAMs, as reflected by lower concentrations of these DBPs measured after re-establishment of a chloramine residual within the facilities than prior to the BPC treatment. However, BPC promoted the formation of halogenated DBPs while a free chlorine residual was maintained. Strategies that minimize application of free chlorine while preventing nitrification are needed to control DBP precursor release in storage facilities.

  15. Development of a Fieldable Air-Coupled Ultrasonic Inspection System

    NASA Astrophysics Data System (ADS)

    Peters, J. J.; Barnard, D. J.; Hsu, D. K.

    2004-02-01

    This paper describes the development of a non-mechanically encoded, simple, field-worthy air-coupled ultrasonic scanning system that gives quantitative information about the size of damage and underlying structure in composite and aluminum aerospace structures. The system consists of the AIRSCAN® air-coupled ultrasonic testing system, the Flock of Birds® real-time motion tracking equipment, a lightweight composite yoke, and laptop PC with data acquisition and processing software. Through transmission C-scan images are generated manually by moving transducers attached to a yoke across the part's surface. The prototype has produced images for a variety of aircraft composite and metal honeycomb structures containing flaws, damages, and repairs. Field tests on commercial and military aircraft as well as rotor blades have begun. Initial test results are shown.

  16. [Assessment of disinfection and sterilization processes in dental practice as an important factors in prevention of infections].

    PubMed

    Podgórska, Marta; Jakimiak, Bozenna; Röhm-Rodowald, Ewa; Chojecka, Agnieszka

    2009-01-01

    The dental health-care settings is an environment where disease transmission occurs easily. Prevention of cross infection is therefore a crucial aspect of dental practice and dental clinic stuffmust adopt certain basic routines while practicing. Infections may be transmitted in the dental operatory through direct contact with blood, oral fluids or other secretions; via indirect contact with contaminated instruments, equipment or environmental surfaces; or by contact with airborne contaminants present in either droplet splatter or aerosols of oral and respiratory fluids. Strategies to prevent dental patient infections have focused on disinfection and sterilization. This study evaluates basic routines in prevention of cross-infection in the dentistry. The sample comprised 100 dentists, who completed questionnaires. Based on inquires the conditions for disinfection and sterilization of medical devices were assessed. The following issues were taken into consideration: the way of disinfection and preparation of the disinfectants, the localization of disinfection, preparing to disinfection, washing and packing of dental devices, the frequency of disinfection, methods of sterilization and the monitoring system, type of sterilizers and the available cycles. The dental practices are well equiped to proceed the steam sterilization, but 33% of dentists don't know the available cycles in their autoclaves. Only 35% of them made sterilization process protocols. Very common are three failures of instruments disinfections: multiple use of disinfectant, adding of disinfectant, adding new instruments. There is still need for improvement in disinfection and sterilization in dental practice, especially including: monitoring and documentation of sterilization process, proper use of disinfectants according to manufactures instructions, frequent disinfection of surfaces which contact with patients. Dental stuff should take part in advanced training courses about disinfection and

  17. [Assessment of disinfection and sterilization processes in dental practice as an important factors in prevention of infections].

    PubMed

    Podgórska, Marta; Jakimiak, Bozenna; Röhm-Rodowald, Ewa; Chojecka, Agnieszka

    2009-01-01

    The dental health-care settings is an environment where disease transmission occurs easily. Prevention of cross infection is therefore a crucial aspect of dental practice and dental clinic stuffmust adopt certain basic routines while practicing. Infections may be transmitted in the dental operatory through direct contact with blood, oral fluids or other secretions; via indirect contact with contaminated instruments, equipment or environmental surfaces; or by contact with airborne contaminants present in either droplet splatter or aerosols of oral and respiratory fluids. Strategies to prevent dental patient infections have focused on disinfection and sterilization. This study evaluates basic routines in prevention of cross-infection in the dentistry. The sample comprised 100 dentists, who completed questionnaires. Based on inquires the conditions for disinfection and sterilization of medical devices were assessed. The following issues were taken into consideration: the way of disinfection and preparation of the disinfectants, the localization of disinfection, preparing to disinfection, washing and packing of dental devices, the frequency of disinfection, methods of sterilization and the monitoring system, type of sterilizers and the available cycles. The dental practices are well equiped to proceed the steam sterilization, but 33% of dentists don't know the available cycles in their autoclaves. Only 35% of them made sterilization process protocols. Very common are three failures of instruments disinfections: multiple use of disinfectant, adding of disinfectant, adding new instruments. There is still need for improvement in disinfection and sterilization in dental practice, especially including: monitoring and documentation of sterilization process, proper use of disinfectants according to manufactures instructions, frequent disinfection of surfaces which contact with patients. Dental stuff should take part in advanced training courses about disinfection and

  18. Effect of different disinfection protocols on microbial and biofilm contamination of dental unit waterlines in community dental practices.

    PubMed

    Dallolio, Laura; Scuderi, Amalia; Rini, Maria S; Valente, Sabrina; Farruggia, Patrizia; Sabattini, Maria A Bucci; Pasquinelli, Gianandrea; Acacci, Anna; Roncarati, Greta; Leoni, Erica

    2014-02-18

    Output water from dental unit waterlines (DUWLs) may be a potential source of infection for both dental healthcare staff and patients. This study compared the efficacy of different disinfection methods with regard to the water quality and the presence of biofilm in DUWLs. Five dental units operating in a public dental health care setting were selected. The control dental unit had no disinfection system; two were disinfected intermittently with peracetic acid/hydrogen peroxide 0.26% and two underwent continuous disinfection with hydrogen peroxide/silver ions (0.02%) and stabilized chlorine dioxide (0.22%), respectively. After three months of applying the disinfection protocols, continuous disinfection systems were more effective than intermittent systems in reducing the microbial contamination of the water, allowing compliance with the CDC guidelines and the European Council regulatory thresholds for drinking water. P. aeruginosa, Legionella spp, sulphite-reducing Clostridium spores, S. aureus and β-haemolytic streptococci were also absent from units treated with continuous disinfection. The biofilm covering the DUWLs was more extensive, thicker and more friable in the intermittent disinfection dental units than in those with continuous disinfection. Overall, the findings showed that the products used for continuous disinfection of dental unit waterlines showed statistically better results than the intermittent treatment products under the study conditions.

  19. Effect of Different Disinfection Protocols on Microbial and Biofilm Contamination of Dental Unit Waterlines in Community Dental Practices

    PubMed Central

    Dallolio, Laura; Scuderi, Amalia; Rini, Maria S.; Valente, Sabrina; Farruggia, Patrizia; Bucci Sabattini, Maria A.; Pasquinelli, Gianandrea; Acacci, Anna; Roncarati, Greta; Leoni, Erica

    2014-01-01

    Output water from dental unit waterlines (DUWLs) may be a potential source of infection for both dental healthcare staff and patients. This study compared the efficacy of different disinfection methods with regard to the water quality and the presence of biofilm in DUWLs. Five dental units operating in a public dental health care setting were selected. The control dental unit had no disinfection system; two were disinfected intermittently with peracetic acid/hydrogen peroxide 0.26% and two underwent continuous disinfection with hydrogen peroxide/silver ions (0.02%) and stabilized chlorine dioxide (0.22%), respectively. After three months of applying the disinfection protocols, continuous disinfection systems were more effective than intermittent systems in reducing the microbial contamination of the water, allowing compliance with the CDC guidelines and the European Council regulatory thresholds for drinking water. P. aeruginosa, Legionella spp, sulphite-reducing Clostridium spores, S. aureus and β-haemolytic streptococci were also absent from units treated with continuous disinfection. The biofilm covering the DUWLs was more extensive, thicker and more friable in the intermittent disinfection dental units than in those with continuous disinfection. Overall, the findings showed that the products used for continuous disinfection of dental unit waterlines showed statistically better results than the intermittent treatment products under the study conditions. PMID:24552789

  20. Effect of different disinfection protocols on microbial and biofilm contamination of dental unit waterlines in community dental practices.

    PubMed

    Dallolio, Laura; Scuderi, Amalia; Rini, Maria S; Valente, Sabrina; Farruggia, Patrizia; Sabattini, Maria A Bucci; Pasquinelli, Gianandrea; Acacci, Anna; Roncarati, Greta; Leoni, Erica

    2014-02-01

    Output water from dental unit waterlines (DUWLs) may be a potential source of infection for both dental healthcare staff and patients. This study compared the efficacy of different disinfection methods with regard to the water quality and the presence of biofilm in DUWLs. Five dental units operating in a public dental health care setting were selected. The control dental unit had no disinfection system; two were disinfected intermittently with peracetic acid/hydrogen peroxide 0.26% and two underwent continuous disinfection with hydrogen peroxide/silver ions (0.02%) and stabilized chlorine dioxide (0.22%), respectively. After three months of applying the disinfection protocols, continuous disinfection systems were more effective than intermittent systems in reducing the microbial contamination of the water, allowing compliance with the CDC guidelines and the European Council regulatory thresholds for drinking water. P. aeruginosa, Legionella spp, sulphite-reducing Clostridium spores, S. aureus and β-haemolytic streptococci were also absent from units treated with continuous disinfection. The biofilm covering the DUWLs was more extensive, thicker and more friable in the intermittent disinfection dental units than in those with continuous disinfection. Overall, the findings showed that the products used for continuous disinfection of dental unit waterlines showed statistically better results than the intermittent treatment products under the study conditions. PMID:24552789

  1. Electrochemical disinfection of toilet wastewater using wastewater electrolysis cell.

    PubMed

    Huang, Xiao; Qu, Yan; Cid, Clément A; Finke, Cody; Hoffmann, Michael R; Lim, Keahying; Jiang, Sunny C

    2016-04-01

    The paucity of proper sanitation facilities has contributed to the spread of waterborne diseases in many developing countries. The primary goal of this study was to demonstrate the feasibility of using a wastewater electrolysis cell (WEC) for toilet wastewater disinfection. The treated wastewater was designed to reuse for toilet flushing and agricultural irrigation. Laboratory-scale electrochemical (EC) disinfection experiments were performed to investigate the disinfection efficiency of the WEC with four seeded microorganisms (Escherichia coli, Enterococcus, recombinant adenovirus serotype 5, and bacteriophage MS2). In addition, the formation of organic disinfection byproducts (DBPs) trihalomethanes (THMs) and haloacetic acids (HAA5) at the end of the EC treatment was also investigated. The results showed that at an applied cell voltage of +4 V, the WEC achieved 5-log10 reductions of all four seeded microorganisms in real toilet wastewater within 60 min. In contrast, chemical chlorination (CC) disinfection using hypochlorite [NaClO] was only effective for the inactivation of bacteria. Due to the rapid formation of chloramines, less than 0.5-log10 reduction of MS2 was observed in toilet wastewater even at the highest [NaClO] dosage (36 mg/L, as Cl2) over a 1 h reaction. Experiments using laboratory model waters showed that free reactive chlorine generated in situ during EC disinfection process was the main disinfectant responsible for the inactivation of microorganisms. However, the production of hydroxyl radicals [OH], and other reactive oxygen species by the active bismuth-doped TiO2 anode were negligible under the same electrolytic conditions. The formation of THMs and HAA5 were found to increase with higher applied cell voltage. Based on the energy consumption estimates, the WEC system can be operated using solar energy stored in a DC battery as the sole power source.

  2. Electrochemical disinfection of toilet wastewater using wastewater electrolysis cell

    PubMed Central

    Huang, Xiao; Qu, Yan; Cid, Clément A.; Finke, Cody; Hoffmann, Michael R.; Lim, Keahying; Jiang, Sunny C.

    2016-01-01

    The paucity of proper sanitation facilities has contributed to the spread of waterborne diseases in many developing countries. The primary goal of this study was to demonstrate the feasibility of using a wastewater electrolysis cell (WEC) for toilet wastewater disinfection. The treated wastewater was designed to reuse for toilet flushing and agricultural irrigation. Laboratory-scale electrochemical (EC) disinfection experiments were performed to investigate the disinfection efficiency of the WEC with four seeded microorganisms (Escherichia coli, Enterococcus, recombinant adenovirus serotype 5, and bacteriophage MS2). In addition, the formation of organic disinfection byproducts (DBPs) trihalomethanes (THMs) and haloacetic acids (HAA5) at the end of the EC treatment was also investigated. The results showed that at an applied cell voltage of +4 V, the WEC achieved 5-log10 reductions of all four seeded microorganisms in real toilet wastewater within 60 min. In contrast, chemical chlorination (CC) disinfection using hypochlorite [NaClO] was only effective for the inactivation of bacteria. Due to the rapid formation of chloramines, less than 0.5-log10 reduction of MS2 was observed in toilet wastewater even at the highest [NaClO] dosage (36 mg/L, as Cl2) over a 1 h reaction. Experiments using laboratory model waters showed that free reactive chlorine generated in situ during EC disinfection process was the main disinfectant responsible for the inactivation of microorganisms. However, the production of hydroxyl radicals [•OH], and other reactive oxygen species by the active bismuth-doped TiO2 anode were negligible under the same electrolytic conditions. The formation of THMs and HAA5 were found to increase with higher applied cell voltage. Based on the energy consumption estimates, the WEC system can be operated using solar energy stored in a DC battery as the sole power source. PMID:26854604

  3. [The problem of heat activation of bacterial spores after disinfection with regard to an aerosol method of decontaminating equipment and rooms].

    PubMed

    Fuhrmann, H; Floerke, I; Böhm, K H

    1986-10-01

    This paper describes investigations on disinfection of germ carriers, contaminated with an alcoholic suspension of Bacillus cereus or Bacillus subtilis. Result of disinfection is compared with that of an additional heat treatment (80 degrees C, 60 min) after disinfection. Besides Formalin, Tegodor forte (Th. Goldschmidt, Essen) and P 3 oxonia active (Henkel KG, Düsseldorf) are tested with different concentration and duration. Heat activation was possible with all three disinfectants. For illuminating the conditions of activation, circumstances of heat action after disinfection with formaldehyde-aerosol have been varied. Heat activation in dry air, moist air and distilled water was not successful. Only in Nutrient Broth (Standard I-Bouillon; Merck, Darmstadt) spores were viable again, after activation. Addition of serum as a protective cover had no influence on the result. Consequences of the results on a disinfection method with formaldehyde-aerosol are discussed.

  4. Transforming the NAS: The Next Generation Air Traffic Control System

    NASA Technical Reports Server (NTRS)

    Erzberger, Heinz

    2004-01-01

    The next-generation air traffic control system must be designed to safely and efficiently accommodate the large growth of traffic expected in the near future. It should be sufficiently scalable to contend with the factor of 2 or more increase in demand expected by the year 2020. Analysis has shown that the current method of controlling air traffic cannot be scaled up to provide such levels of capacity. Therefore, to achieve a large increase in capacity while also giving pilots increased freedom to optimize their flight trajectories requires a fundamental change in the way air traffic is controlled. The key to achieving a factor of 2 or more increase in airspace capacity is to automate separation monitoring and control and to use an air-ground data link to send trajectories and clearances directly between ground-based and airborne systems. In addition to increasing capacity and offering greater flexibility in the selection of trajectories, this approach also has the potential to increase safety by reducing controller and pilot errors that occur in routine monitoring and voice communication tasks.

  5. Health effects of drinking water disinfectants and disinfection by-products

    SciTech Connect

    Condie, L.W.; Bercz, J.P.

    1986-01-01

    This paper summarizes toxicological studies conducted with drinking water disinfectants. Toxicological effects, which are associated with the disinfectants themselves as well as with the by-products formed when disinfectants react with organic material present in water, are considered. The health impact of chemical reactions occurring between residual disinfectants and nutrients in the gastrointestinal tract is also discussed. 40 references, 5 tables.

  6. 40 CFR 141.54 - Maximum residual disinfectant level goals for disinfectants.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Maximum residual disinfectant level goals for disinfectants. 141.54 Section 141.54 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Goals and Maximum Residual Disinfectant Level Goals § 141.54 Maximum residual disinfectant level...

  7. 40 CFR 141.54 - Maximum residual disinfectant level goals for disinfectants.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Maximum residual disinfectant level goals for disinfectants. 141.54 Section 141.54 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Goals and Maximum Residual Disinfectant Level Goals § 141.54 Maximum residual disinfectant level...

  8. 40 CFR 141.54 - Maximum residual disinfectant level goals for disinfectants.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Maximum residual disinfectant level goals for disinfectants. 141.54 Section 141.54 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Goals and Maximum Residual Disinfectant Level Goals § 141.54 Maximum residual disinfectant level...

  9. 40 CFR 141.54 - Maximum residual disinfectant level goals for disinfectants.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Maximum residual disinfectant level goals for disinfectants. 141.54 Section 141.54 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Goals and Maximum Residual Disinfectant Level Goals § 141.54 Maximum residual disinfectant level...

  10. 40 CFR 141.54 - Maximum residual disinfectant level goals for disinfectants.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Maximum residual disinfectant level goals for disinfectants. 141.54 Section 141.54 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Goals and Maximum Residual Disinfectant Level Goals § 141.54 Maximum residual disinfectant level...

  11. High Technology Centrifugal Compressor for Commercial Air Conditioning Systems

    SciTech Connect

    Ruckes, John

    2006-04-15

    R&D Dynamics, Bloomfield, CT in partnership with the State of Connecticut has been developing a high technology, oil-free, energy-efficient centrifugal compressor called CENVA for commercial air conditioning systems under a program funded by the US Department of Energy. The CENVA compressor applies the foil bearing technology used in all modern aircraft, civil and military, air conditioning systems. The CENVA compressor will enhance the efficiency of water and air cooled chillers, packaged roof top units, and other air conditioning systems by providing an 18% reduction in energy consumption in the unit capacity range of 25 to 350 tons of refrigeration The technical approach for CENVA involved the design and development of a high-speed, oil-free foil gas bearing-supported two-stage centrifugal compressor, CENVA encompassed the following high technologies, which are not currently utilized in commercial air conditioning systems: Foil gas bearings operating in HFC-134a; Efficient centrifugal impellers and diffusers; High speed motors and drives; and System integration of above technologies. Extensive design, development and testing efforts were carried out. Significant accomplishments achieved under this program are: (1) A total of 26 builds and over 200 tests were successfully completed with successively improved designs; (2) Use of foil gas bearings in refrigerant R134a was successfully proven; (3) A high speed, high power permanent magnet motor was developed; (4) An encoder was used for signal feedback between motor and controller. Due to temperature limitations of the encoder, the compressor could not operate at higher speed and in turn at higher pressure. In order to alleviate this problem a unique sensorless controller was developed; (5) This controller has successfully been tested as stand alone; however, it has not yet been integrated and tested as a system; (6) The compressor successfully operated at water cooled condensing temperatures Due to temperature

  12. Liquid Desiccant in Air Conditioners: Nano-Engineered Porous Hollow Fiber Membrane-Based Air Conditioning System

    SciTech Connect

    2010-09-02

    BEETIT Project: UTRC is developing an air conditioning system that is optimized for use in warm and humid climates. UTRC’s air conditioning system integrates a liquid drying agent or desiccant and a traditional vapor compression system found in 90% of air conditioners. The drying agent reduces the humidity in the air before it is cooled, using less energy. The technology uses a membrane as a barrier between the air and the liquid salt stream allowing only water vapor to pass through and not the salt molecules. This solves an inherent problem with traditional liquid desiccant systems—carryover of the liquid drying agent into the conditioned air stream—which eliminates corrosion and health issues

  13. New research on bioregenerative air/water purification systems

    NASA Technical Reports Server (NTRS)

    Johnson, Anne H.; Ellender, R. D.; Watkins, Paul J.

    1991-01-01

    For the past several years, air and water purification systems have been developed and used. This technology is based on the combined activities of plants and microorganisms as they function in a natural environment. More recently, researchers have begun to address the problems associated with indoor air pollution. Various common houseplants are currently being evaluated for their abilities to reduce concentrations of volatile organic compounds (VOCS) such as formaldehyde and benzene. With development of the Space Exploration Initiative, missions will increase in duration, and problems with resupply necessitates implementation of regenerative technology. Aspects of bioregenerative technology have been included in a habitat known as the BioHome. The ultimate goal is to use this technology in conjunction with physicochemical systems for air and water purification within closed systems. This study continued the risk assessment of bioregenerative technology with emphasis on biological hazards. In an effort to evaluate the risk for human infection, analyses were directed at enumeration of fecal streptococci and enteric viruses with the BioHome waste water treatment system.

  14. Operational air quality forecasting system for Spain: CALIOPE

    NASA Astrophysics Data System (ADS)

    Baldasano, J. M.; Piot, M.; Jorba, O.; Goncalves, M.; Pay, M.; Pirez, C.; Lopez, E.; Gasso, S.; Martin, F.; García-Vivanco, M.; Palomino, I.; Querol, X.; Pandolfi, M.; Dieguez, J. J.; Padilla, L.

    2009-12-01

    The European Commission (EC) and the United States Environmental Protection Agency (US-EPA) have shown great concerns to understand the transport and dynamics of pollutants in the atmosphere. According to the European directives (1996/62/EC, 2002/3/EC, 2008/50/EC), air quality modeling, if accurately applied, is a useful tool to understand the dynamics of air pollutants, to analyze and forecast the air quality, and to develop programs reducing emissions and alert the population when health-related issues occur. The CALIOPE project, funded by the Spanish Ministry of the Environment, has the main objective to establish an air quality forecasting system for Spain. A partnership of four research institutions composes the CALIOPE project: the Barcelona Supercomputing Center (BSC), the center of investigation CIEMAT, the Earth Sciences Institute ‘Jaume Almera’ (IJA-CSIC) and the CEAM Foundation. CALIOPE will become the official Spanish air quality operational system. This contribution focuses on the recent developments and implementation of the integrated modelling system for the Iberian Peninsula (IP) and Canary Islands (CI) with a high spatial and temporal resolution (4x4 sq. km for IP and 2x2 sq. km for CI, 1 hour), namely WRF-ARW/HERMES04/CMAQ/BSC-DREAM. The HERMES04 emission model has been specifically developed as a high-resolution (1x1 sq. km, 1 hour) emission model for Spain. It includes biogenic and anthropogenic emissions such as on-road and paved-road resuspension production, power plant generation, ship and plane traffic, airports and ports activities, industrial and agricultural sectors as well as domestic and commercial emissions. The qualitative and quantitative evaluation of the model was performed for a reference year (2004) using data from ground-based measurement networks. The products of the CALIOPE system will provide 24h and 48h forecasts for O3, NO2, SO2, CO, PM10 and PM2.5 at surface level. An operational evaluation system has been developed

  15. Applied patent RFID systems for building reacting HEPA air ventilation system in hospital operation rooms.

    PubMed

    Lin, Jesun; Pai, Jar-Yuan; Chen, Chih-Cheng

    2012-12-01

    RFID technology, an automatic identification and data capture technology to provide identification, tracing, security and so on, was widely applied to healthcare industry in these years. Employing HEPA ventilation system in hospital is a way to ensure healthful indoor air quality to protect patients and healthcare workers against hospital-acquired infections. However, the system consumes lots of electricity which cost a lot. This study aims to apply the RFID technology to offer a unique medical staff and patient identification, and reacting HEPA air ventilation system in order to reduce the cost, save energy and prevent the prevalence of hospital-acquired infection. The system, reacting HEPA air ventilation system, contains RFID tags (for medical staffs and patients), sensor, and reacting system which receives the information regarding the number of medical staff and the status of the surgery, and controls the air volume of the HEPA air ventilation system accordingly. A pilot program was carried out in a unit of operation rooms of a medical center with 1,500 beds located in central Taiwan from Jan to Aug 2010. The results found the air ventilation system was able to function much more efficiently with less energy consumed. Furthermore, the indoor air quality could still keep qualified and hospital-acquired infection or other occupational diseases could be prevented.

  16. Evaluation of approaches to quantify total residual oxidants in ballast water management systems employing chlorine for disinfection.

    PubMed

    Zimmer-Faust, Amity G; Ambrose, Richard F; Tamburri, Mario N

    2014-01-01

    With the maturation and certification of several ballast water management systems that employ chlorine as biocide to prevent the spread of invasive species, there is a clear need for accurate and reliable total residual oxidants (TRO) technology to monitor treatment dose and assure the environmental safety of treated water discharged from ships. In this study, instruments used to measure TRO in wastewater and drinking water applications were evaluated for their performance in scenarios mimicking a ballast water treatment application (e.g., diverse hold times, temperatures, and salinities). Parameters chosen for testing these technologies in the past do not reflect conditions expected during ballast water treatment. Salinity, temperature, and oxidant concentration all influenced the response of amperometric sensors. Oxidation reduction potential (ORP) sensors performed more consistently than amperometric sensors under different conditions but it may be difficult to correlate ORP and TRO measurements for the multitude of biogeochemical conditions found naturally in ballast water. N,N-diethyl-p-phenylenediamine (DPD) analyzers and amperometric sensors were also tested under intermittent sampling conditions mimicking a ballasting scenario, with cyclical dosage and discharge operations. When sampling was intermittent, amperometric sensors required excessive response and conditioning times, whereas DPD analyzers provided reasonable estimates of TRO under the ballasting scenario.

  17. Design, Development, and Performance Evaluation of Solar Heating System for Disinfection of Domestic Roof-Harvested Rainwater

    PubMed Central

    Sangodoyin, A. Y.

    2015-01-01

    A box-type solar heater was designed, constructed, and used to determine the effect of solar heating on quality of domestic roof-harvested rainwater (DRHRW). During testing, naturally contaminated DRHRW was harvested in Ibadan, Nigeria, and released into the system at 93.96 Lh−1 (2.61 × 10−5 m3 s−1) in a continuous flow process. Water temperatures at inlet, within the heating chamber, and at outlet from the heating chamber and solar radiation were monitored at 10 min interval. Samples were collected at both inlet to and outlet from the heating chamber at 10 min interval for microbiological analysis. The highest plate stagnation temperature, under no-load condition, was 100°C. The solar water heater attained a maximum operational temperature of 75°C with 89.6 and 94.4% reduction in total viable count and total coliform count, respectively, while Escherichia coli and Staphylococcus aureus were completely eradicated at this temperature. The solar heater developed proved to be effective in enhancing potability of DRHRW in Ibadan, Nigeria. This may be an appropriate household water treatment technology for developing countries, hence, a way of resolving problem of low quality water for potable uses. PMID:27347529

  18. Design, Development, and Performance Evaluation of Solar Heating System for Disinfection of Domestic Roof-Harvested Rainwater.

    PubMed

    Akintola, O A; Sangodoyin, A Y

    2015-01-01

    A box-type solar heater was designed, constructed, and used to determine the effect of solar heating on quality of domestic roof-harvested rainwater (DRHRW). During testing, naturally contaminated DRHRW was harvested in Ibadan, Nigeria, and released into the system at 93.96 Lh(-1) (2.61 × 10(-5) m(3) s(-1)) in a continuous flow process. Water temperatures at inlet, within the heating chamber, and at outlet from the heating chamber and solar radiation were monitored at 10 min interval. Samples were collected at both inlet to and outlet from the heating chamber at 10 min interval for microbiological analysis. The highest plate stagnation temperature, under no-load condition, was 100°C. The solar water heater attained a maximum operational temperature of 75°C with 89.6 and 94.4% reduction in total viable count and total coliform count, respectively, while Escherichia coli and Staphylococcus aureus were completely eradicated at this temperature. The solar heater developed proved to be effective in enhancing potability of DRHRW in Ibadan, Nigeria. This may be an appropriate household water treatment technology for developing countries, hence, a way of resolving problem of low quality water for potable uses.

  19. Drinking water and biofilm disinfection by Fenton-like reaction.

    PubMed

    Gosselin, F; Madeira, L M; Juhna, T; Block, J C

    2013-10-01

    A Fenton-like disinfection process was conducted with Fenton's reagent (H2O2) at pH 3 or 5 on autochthonous drinking water biofilms grown on corroded or non-corroded pipe material. The biofilm disinfection by Fenton-like oxidation was limited by the low content of iron and copper in the biomass grown on non-corroded plumbing. It was slightly improved by spiking the distribution system with some additional iron source (soluble iron II or ferrihydrite particles appeared as interesting candidates). However successful in situ disinfection of biofilms was only achieved in fully corroded cast iron pipes using H2O2 and adjusting the pH to 5. These new results provide additional support for the use of Fenton's processes for cleaning drinking water distribution systems contaminated with biological agents or organics.

  20. Comparison of sampling procedures and microbiological and non-microbiological parameters to evaluate cleaning and disinfection in broiler houses.

    PubMed

    Luyckx, K; Dewulf, J; Van Weyenberg, S; Herman, L; Zoons, J; Vervaet, E; Heyndrickx, M; De Reu, K

    2015-04-01

    Cleaning and disinfection of the broiler stable environment is an essential part of farm hygiene management. Adequate cleaning and disinfection is essential for prevention and control of animal diseases and zoonoses. The goal of this study was to shed light on the dynamics of microbiological and non-microbiological parameters during the successive steps of cleaning and disinfection and to select the most suitable sampling methods and parameters to evaluate cleaning and disinfection in broiler houses. The effectiveness of cleaning and disinfection protocols was measured in six broiler houses on two farms through visual inspection, adenosine triphosphate hygiene monitoring and microbiological analyses. Samples were taken at three time points: 1) before cleaning, 2) after cleaning, and 3) after disinfection. Before cleaning and after disinfection, air samples were taken in addition to agar contact plates and swab samples taken from various sampling points for enumeration of total aerobic flora, Enterococcus spp., and Escherichia coli and the detection of E. coli and Salmonella. After cleaning, air samples, swab samples, and adenosine triphosphate swabs were taken and a visual score was also assigned for each sampling point. The mean total aerobic flora determined by swab samples decreased from 7.7±1.4 to 5.7±1.2 log CFU/625 cm2 after cleaning and to 4.2±1.6 log CFU/625 cm2 after disinfection. Agar contact plates were used as the standard for evaluating cleaning and disinfection, but in this study they were found to be less suitable than swabs for enumeration. In addition to measuring total aerobic flora, Enterococcus spp. seemed to be a better hygiene indicator to evaluate cleaning and disinfection protocols than E. coli. All stables were Salmonella negative, but the detection of its indicator organism E. coli provided additional information for evaluating cleaning and disinfection protocols. Adenosine triphosphate analyses gave additional information about the

  1. D-Zero Instrument Air System Humidity Transmitter Evaluation

    SciTech Connect

    Serges, T.J.; /Fermilab

    1988-07-15

    This report shows the findings that resulted in the purchase of the optimum dew point hygrometer for use in the D-Zero instrument air system (see diagram 2 on page 9). The hygrometer will monitor the air syste m to insure that the dew point level does not go above the normal operating output of the driers (this precise value will be determined during initial system start-up). The following criteria was used in the evaluation: (1) Long term durability; (2) Minimum calibration; (3) Indicate a dew point level down to -40 C accurately; (4) Designed to work in a low humidity region; (5) Minimum maintenance; (6) Fast response time; and (7) Lowest cost provided all other criteria is met.

  2. Regenerable Air Purification System for Gas-Phase Contaminant Control

    NASA Technical Reports Server (NTRS)

    Constantinescu, Ileana C.; Qi, Nan; LeVan, M. Douglas; Finn, Cory K.; Finn, John E.; Luna, Bernadette (Technical Monitor)

    2000-01-01

    A regenerable air purification system (RAPS) that uses water vapor to displace adsorbed contaminants from an. adsorbent column into a closed oxidation loop is under development through cooperative R&D between Vanderbilt University and NASA Ames Research Center. A unit based on this design can be used for removing trace gas-phase contaminants from spacecraft cabin air or from polluted process streams including incinerator exhaust. Recent work has focused on fabrication and operation of a RAPS breadboard at NASA Ames, and on measurement of adsorption isotherm data for several important organic compounds at Vanderbilt. These activities support the use and validation of RAPS modeling software also under development at Vanderbilt, which will in turn be used to construct a prototype system later in the project.

  3. 47 CFR 22.859 - Incumbent commercial aviation air-ground systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Incumbent commercial aviation air-ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service Commercial Aviation Air-Ground Systems § 22.859 Incumbent commercial aviation air-ground systems. This section contains rules...

  4. 47 CFR 22.859 - Incumbent commercial aviation air-ground systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Incumbent commercial aviation air-ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service Commercial Aviation Air-Ground Systems § 22.859 Incumbent commercial aviation air-ground systems. This section contains rules...

  5. 47 CFR 22.859 - Incumbent commercial aviation air-ground systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Incumbent commercial aviation air-ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service Commercial Aviation Air-Ground Systems § 22.859 Incumbent commercial aviation air-ground systems. This section contains rules...

  6. 47 CFR 22.857 - Channel plan for commercial aviation air-ground systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Channel plan for commercial aviation air-ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service Commercial Aviation Air-Ground Systems § 22.857 Channel plan for commercial aviation air-ground systems. The 849-851 MHz and 894-896...

  7. 47 CFR 22.859 - Incumbent commercial aviation air-ground systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Incumbent commercial aviation air-ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service Commercial Aviation Air-Ground Systems § 22.859 Incumbent commercial aviation air-ground systems. This section contains rules...

  8. 47 CFR 22.857 - Channel plan for commercial aviation air-ground systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Channel plan for commercial aviation air-ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service Commercial Aviation Air-Ground Systems § 22.857 Channel plan for commercial aviation air-ground systems. The 849-851 MHz and 894-896...

  9. 47 CFR 22.857 - Channel plan for commercial aviation air-ground systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Channel plan for commercial aviation air-ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service Commercial Aviation Air-Ground Systems § 22.857 Channel plan for commercial aviation air-ground systems. The 849-851 MHz and 894-896...

  10. 47 CFR 22.857 - Channel plan for commercial aviation air-ground systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Channel plan for commercial aviation air-ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service Commercial Aviation Air-Ground Systems § 22.857 Channel plan for commercial aviation air-ground systems. The 849-851 MHz and 894-896...

  11. 47 CFR 22.859 - Incumbent commercial aviation air-ground systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Incumbent commercial aviation air-ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service Commercial Aviation Air-Ground Systems § 22.859 Incumbent commercial aviation air-ground systems. This section contains rules...

  12. 47 CFR 22.857 - Channel plan for commercial aviation air-ground systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Channel plan for commercial aviation air-ground... CARRIER SERVICES PUBLIC MOBILE SERVICES Air-Ground Radiotelephone Service Commercial Aviation Air-Ground Systems § 22.857 Channel plan for commercial aviation air-ground systems. The 849-851 MHz and 894-896...

  13. Modeling urban air pollution with optimized hierarchical fuzzy inference system.

    PubMed

    Tashayo, Behnam; Alimohammadi, Abbas

    2016-10-01

    Environmental exposure assessments (EEA) and epidemiological studies require urban air pollution models with appropriate spatial and temporal resolutions. Uncertain available data and inflexible models can limit air pollution modeling techniques, particularly in under developing countries. This paper develops a hierarchical fuzzy inference system (HFIS) to model air pollution under different land use, transportation, and meteorological conditions. To improve performance, the system treats the issue as a large-scale and high-dimensional problem and develops the proposed model using a three-step approach. In the first step, a geospatial information system (GIS) and probabilistic methods are used to preprocess the data. In the second step, a hierarchical structure is generated based on the problem. In the third step, the accuracy and complexity of the model are simultaneously optimized with a multiple objective particle swarm optimization (MOPSO) algorithm. We examine the capabilities of the proposed model for predicting daily and annual mean PM2.5 and NO2 and compare the accuracy of the results with representative models from existing literature. The benefits provided by the model features, including probabilistic preprocessing, multi-objective optimization, and hierarchical structure, are precisely evaluated by comparing five different consecutive models in terms of accuracy and complexity criteria. Fivefold cross validation is used to assess the performance of the generated models. The respective average RMSEs and coefficients of determination (R (2)) for the test datasets using proposed model are as follows: daily PM2.5 = (8.13, 0.78), annual mean PM2.5 = (4.96, 0.80), daily NO2 = (5.63, 0.79), and annual mean NO2 = (2.89, 0.83). The obtained results demonstrate that the developed hierarchical fuzzy inference system can be utilized for modeling air pollution in EEA and epidemiological studies.

  14. Control of Future Air Traffic Systems via Complexity Bound Management

    NASA Technical Reports Server (NTRS)

    Alexandrov, Natalia

    2013-01-01

    The complexity of the present system for managing air traffic has led to "discreteness" in approaches to creating new concepts: new concepts are created as point designs, based on experience, expertise, and creativity of the proposer. Discrete point designs may be highly successful but they are difficult to substantiate in the face of equally strong substantiation of competing concepts, as well as the state of the art in concept evaluation via simulations. Hybrid concepts may present a compromise - the golden middle. Yet a hybrid of sometimes in principle incompatible concepts forms another point design that faces the challenge of substantiation and validation. We are faced with the need to re-design the air transportation system ab initio. This is a daunting task, especially considering the problem of transitioning from the present system to any fundamentally new system. However, design from scratch is also an opportunity to reconsider approaches to new concept development. In this position paper we propose an approach, Optimized Parametric Functional Design, for systematic development of concepts for management and control of airspace systems, based on optimization formulations in terms of required system functions and states. This reasoning framework, realizable in the context of ab initio system design, offers an approach to deriving substantiated airspace management and control concepts. With growing computational power, we hope that the approach will also yield a methodology for actual dynamic control of airspace

  15. Nozzle for discharging ventilation air from a ventilation system

    SciTech Connect

    Elfverson, S.E.

    1986-09-30

    This patent describes a nozzle for discharging ventilation air from a ventilation system, preferably arranged in a vehicle, including at least one outlet housing with a through-flow duct for ventilation air, a fixed plate transverse to the flow duct and rigidly attached to the outlet housing, and a plurality of plates parallel to the fixed plate. These plates are mutually displaceable in a direction transverse to the flow duct under the action of a control lever passing through the plates, the plates being formed with perforation patterns, which in coaction form ventilation ducts through which the ventilation air can flow and in response to the setting of the control lever cause deviation of the flow direction of the ventilation air. Each displaceable plate is formed with a grid cross comprising at least two intersecting bars, of which one bar has a substantially circular cross section, while the other bar has a substantially elliptical cross section and wherein the control lever is adapted to grip round a grid cross, the control lever having two pairs of longitudinal slots. One pair of the slots is adapted to grip without play one of the intersecting bars in each respective grid cross. The other pair of slots comprises a first slot adapted to grip without play the other of the intersecting bars, and a second slot formed with a width disabling engagement with the other of the intersecting bars.

  16. Aviation System Analysis Capability Air Carrier Investment Model-Cargo

    NASA Technical Reports Server (NTRS)

    Johnson, Jesse; Santmire, Tara

    1999-01-01

    The purpose of the Aviation System Analysis Capability (ASAC) Air Cargo Investment Model-Cargo (ACIMC), is to examine the economic effects of technology investment on the air cargo market, particularly the market for new cargo aircraft. To do so, we have built an econometrically based model designed to operate like the ACIM. Two main drivers account for virtually all of the demand: the growth rate of the Gross Domestic Product (GDP) and changes in the fare yield (which is a proxy of the price charged or fare). These differences arise from a combination of the nature of air cargo demand and the peculiarities of the air cargo market. The net effect of these two factors are that sales of new cargo aircraft are much less sensitive to either increases in GDP or changes in the costs of labor, capital, fuel, materials, and energy associated with the production of new cargo aircraft than the sales of new passenger aircraft. This in conjunction with the relatively small size of the cargo aircraft market means technology improvements to the cargo aircraft will do relatively very little to spur increased sales of new cargo aircraft.

  17. Disinfection of Human Teeth for Educational Purposes.

    ERIC Educational Resources Information Center

    Tate, William H.; White, Robert S.

    1991-01-01

    A study investigated the efficacy of glutaraldehyde and several other disinfectants for disinfecting teeth to be used for teaching and research, as an alternative to autoclaving for teeth with amalgam restorations. Results indicate that formalin was the only disinfectant that penetrated tooth pulp chambers in effective antimicrobial…

  18. [Drinking water decontamination with isolative sorbent disinfectants].

    PubMed

    Krasnov, M S

    2004-01-01

    Drinking water can be decontaminated with the use of isolative sorbent disinfectants. Consideration of the effectiveness of water disinfectants and the sorptive power of porous materials against bacteria and viruses attested to the favour of iodine and silver-containing disinfectants and their compositions on porous aggressive carriers to be employed in extreme conditions such as on board crewed space vehicles.

  19. Air to fuel ratio control system for internal combustion engine

    SciTech Connect

    Nishimura, Y.; Oyama, Y.

    1980-05-06

    An air to fuel ratio control system for an internal combustion engine having a fixed venturi type carburetor is disclosed. The air to fuel ratio control system comprises a device for extracting an atmospheric pressure within a venturi or a pressure corresponding to a relieved venturi vacuum, a device for extracting a static fuel pressure downstream of a main jet provided in a fuel path, a device for comparing those pressures directly or indirectly and a device for controlling the static fuel pressure in accordance with an output of the detecting device. Control is made such that the difference between those pressures is always maintained substantially constant. The air to fuel ratio control system may further comprise a device for detecting composition of exhaust gas of the engine. An output of the composition detecting device is applied to a control device which controls the static fuel pressure based on the output of the differential pressure detecting device and the output of the composition detecting device.

  20. Effect of ionizing radiation on moist air systems

    SciTech Connect

    Reed, D.T.; Van Konynenburg, R.A.

    1987-12-31

    The radiation chemistry of nitrogen/oxygen/water systems is reviewed. General radiolytic effects in dry nitrogen/oxygen systems are relatively well characterized. Irradiation results in the formation of steady state concentrations of ozone, nitrous oxide and nitrogen dioxide. In closed systems, the concentration observed depends on the total dose, temperature and initial gas composition. Only three studies have been published that focus on the radiation chemistry of nitrogen/oxygen/water homogeneous gas systems. Mixed phase work that is relevant to the gaseous system is also summarized. The presence of water vapor results in the formation of nitric acid and significantly changes the chemistry observed in dry air systems. Mechanistic evidence from the studies reviewed are summarized and discussed in relation to characterizing the gas phase during the containment period of a repository in tuff.

  1. Disinfection by-product formation during seawater desalination: A review.

    PubMed

    Kim, Daekyun; Amy, Gary L; Karanfil, Tanju

    2015-09-15

    Due to increased freshwater demand across the globe, seawater desalination has become the technology of choice in augmenting water supplies in many parts of the world. The use of chemical disinfection is necessary in desalination plants for pre-treatment to control both biofouling as well as the post-disinfection of desalinated water. Although chlorine is the most commonly used disinfectant in desalination plants, its reaction with organic matter produces various disinfection by-products (DBPs) (e.g., trihalomethanes [THMs], haloacetic acids [HAAs], and haloacetonitriles [HANs]), and some DBPs are regulated in many countries due to their potential risks to public health. To reduce the formation of chlorinated DBPs, alternative oxidants (disinfectants) such as chloramines, chlorine dioxide, and ozone can be considered, but they also produce other types of DBPs. In addition, due to high levels of bromide and iodide concentrations in seawater, highly cytotoxic and genotoxic DBP species (i.e., brominated and iodinated DBPs) may form in distribution systems, especially when desalinated water is blended with other source waters having higher levels of organic matter. This article reviews the knowledge accumulated in the last few decades on DBP formation during seawater desalination, and summarizes in detail, the occurrence of DBPs in various thermal and membrane plants involving different desalination processes. The review also identifies the current challenges and future research needs for controlling DBP formation in seawater desalination plants and to reduce the potential toxicity of desalinated water.

  2. Disinfection of water by adsorption combined with electrochemical treatment.

    PubMed

    Hussain, S N; de Las Heras, N; Asghar, H M A; Brown, N W; Roberts, E P L

    2014-05-01

    The disinfection performance of a unique process of adsorption combined with electrochemical treatment is evaluated. A flake graphite intercalation compound adsorbent was used, which is effective for the removal of organic contaminants and is amenable to anodic electrochemical regeneration. Adsorption of Escherichia coli on the graphite flake was followed by electrochemical treatment under a range of experimental conditions in a sequential batch reactor. The adsorption of E. coli cells was found to be a fast process and was capable of removing >99.98% of cells from solution after 5 min with a ca. 6.5-log10 reduction in E. coli concentration after 10 min. With electrochemical treatment the adsorbent could be reused, with no decrease in E. coli adsorption observed over five cycles. In the presence of chloride, >8.5-log10 reduction of E. coli concentration was achieved. Disinfection was found to be less effective in the absence of chloride. However, selection of appropriate operating conditions enabled effective disinfection in a chloride free system, reducing the potential for formation of disinfection by-products. The energy consumption required to achieve >8.5-log10 disinfection was 2-7 kWh m(-3).

  3. Disinfection by-product formation during seawater desalination: A review.

    PubMed

    Kim, Daekyun; Amy, Gary L; Karanfil, Tanju

    2015-09-15

    Due to increased freshwater demand across the globe, seawater desalination has become the technology of choice in augmenting water supplies in many parts of the world. The use of chemical disinfection is necessary in desalination plants for pre-treatment to control both biofouling as well as the post-disinfection of desalinated water. Although chlorine is the most commonly used disinfectant in desalination plants, its reaction with organic matter produces various disinfection by-products (DBPs) (e.g., trihalomethanes [THMs], haloacetic acids [HAAs], and haloacetonitriles [HANs]), and some DBPs are regulated in many countries due to their potential risks to public health. To reduce the formation of chlorinated DBPs, alternative oxidants (disinfectants) such as chloramines, chlorine dioxide, and ozone can be considered, but they also produce other types of DBPs. In addition, due to high levels of bromide and iodide concentrations in seawater, highly cytotoxic and genotoxic DBP species (i.e., brominated and iodinated DBPs) may form in distribution systems, especially when desalinated water is blended with other source waters having higher levels of organic matter. This article reviews the knowledge accumulated in the last few decades on DBP formation during seawater desalination, and summarizes in detail, the occurrence of DBPs in various thermal and membrane plants involving different desalination processes. The review also identifies the current challenges and future research needs for controlling DBP formation in seawater desalination plants and to reduce the potential toxicity of desalinated water. PMID:26099832

  4. AirNow Information Management System - Global Earth Observation System of Systems Data Processor for Real-Time Air Quality Data Products

    NASA Astrophysics Data System (ADS)

    Haderman, M.; Dye, T. S.; White, J. E.; Dickerson, P.; Pasch, A. N.; Miller, D. S.; Chan, A. C.

    2012-12-01

    Built upon the success of the U.S. Environmental Protection Agency's (EPA) AirNow program (www.AirNow.gov), the AirNow-International (AirNow-I) system contains an enhanced suite of software programs that process and quality control real-time air quality and environmental data and distribute customized maps, files, and data feeds. The goals of the AirNow-I program are similar to those of the successful U.S. program and include fostering the exchange of environmental data; making advances in air quality knowledge and applications; and building a community of people, organizations, and decision makers in environmental management. In 2010, Shanghai became the first city in China to run this state-of-the-art air quality data management and notification system. AirNow-I consists of a suite of modules (software programs and schedulers) centered on a database. One such module is the Information Management System (IMS), which can automatically produce maps and other data products through the use of GIS software to provide the most current air quality information to the public. Developed with Global Earth Observation System of Systems (GEOSS) interoperability in mind, IMS is based on non-proprietary standards, with preference to formal international standards. The system depends on data and information providers accepting and implementing a set of interoperability arrangements, including technical specifications for collecting, processing, storing, and disseminating shared data, metadata, and products. In particular, the specifications include standards for service-oriented architecture and web-based interfaces, such as a web mapping service (WMS), web coverage service (WCS), web feature service (WFS), sensor web services, and Really Simple Syndication (RSS) feeds. IMS is flexible, open, redundant, and modular. It also allows the merging of data grids to create complex grids that show comprehensive air quality conditions. For example, the AirNow Satellite Data Processor

  5. In vitro activity of disinfectants against Aspergillus spp.

    PubMed

    Mattei, A S; Madrid, I M; Santin, R; Schuch, L F D; Meireles, M C A

    2013-01-01

    Fungi of the Aspergillus genus are widespread and contaminate the environment. Thousands of conidia are released from each phialide and dispersed in the air every day. These fungi are considered important mycose-causing agents in hospitals. Due to this, research to determine prevalent fungi from the Aspergillus genus in hospital environments, and an adequate disinfection program in these areas is are needed. This study evaluated the susceptibility of Aspergillus spp. isolated from a veterinary environment against four disinfectants. Successive dilutions of disinfectants (log2) were used according to CLSI M38-A2 microdilution technique adapted to chemical agents against 18 isolates of this genus. After 72 hours of incubation, the Minimum Inhibiting Concentration and Minimum Fungicidal Concentration capable of inhibiting 50% and 90% of the isolates were determined. Chlorexidine-cetrimine, benzalconium chloride and a chlorophenol derivative proved to be effective against all isolates with a lower MIC than that suggested by the manufacturer, except for the A. flavus strain. Sodium hypochlorite was ineffective against three A. fumigatus, three A. flavus and one A. niger isolate. These results demonstrated that all studied disinfectants were effective against environmental isolates, with the exception of sodium hypochlorite, which showed lower effectiveness.

  6. In vitro activity of disinfectants against Aspergillus spp

    PubMed Central

    Mattei, A.S.; Madrid, I.M.; Santin, R.; Schuch, L.F.D.; Meireles, M.C.A.

    2013-01-01

    Fungi of the Aspergillus genus are widespread and contaminate the environment. Thousands of conidia are released from each phialide and dispersed in the air every day. These fungi are considered important mycose-causing agents in hospitals. Due to this, research to determine prevalent fungi from the Aspergillus genus in hospital environments, and an adequate disinfection program in these areas is are needed. This study evaluated the susceptibility of Aspergillus spp. isolated from a veterinary environment against four disinfectants. Successive dilutions of disinfectants (log2) were used according to CLSI M38-A2 microdilution technique adapted to chemical agents against 18 isolates of this genus. After 72 hours of incubation, the Minimum Inhibiting Concentration and Minimum Fungicidal Concentration capable of inhibiting 50% and 90% of the isolates were determined. Chlorexidine-cetrimine, benzalconium chloride and a chlorophenol derivative proved to be effective against all isolates with a lower MIC than that suggested by the manufacturer, except for the A. flavus strain. Sodium hypochlorite was ineffective against three A. fumigatus, three A. flavus and one A. niger isolate. These results demonstrated that all studied disinfectants were effective against environmental isolates, with the exception of sodium hypochlorite, which showed lower effectiveness. PMID:24294243

  7. Variable oxygen/nitrogen enriched intake air system for internal combustion engine applications

    DOEpatents

    Poola, Ramesh B.; Sekar, Ramanujam R.; Cole, Roger L.

    1997-01-01

    An air supply control system for selectively supplying ambient air, oxygen enriched air and nitrogen enriched air to an intake of an internal combustion engine includes an air mixing chamber that is in fluid communication with the air intake. At least a portion of the ambient air flowing to the mixing chamber is selectively diverted through a secondary path that includes a selectively permeable air separating membrane device due a differential pressure established across the air separating membrane. The permeable membrane device separates a portion of the nitrogen in the ambient air so that oxygen enriched air (permeate) and nitrogen enriched air (retentate) are produced. The oxygen enriched air and the nitrogen enriched air can be selectively supplied to the mixing chamber or expelled to atmosphere. Alternatively, a portion of the nitrogen enriched air can be supplied through another control valve to a monatomic-nitrogen plasma generator device so that atomic nitrogen produced from the nitrogen enriched air can be then injected into the exhaust of the engine. The oxygen enriched air or the nitrogen enriched air becomes mixed with the ambient air in the mixing chamber and then the mixed air is supplied to the intake of the engine. As a result, the air being supplied to the intake of the engine can be regulated with respect to the concentration of oxygen and/or nitrogen.

  8. Air pollution control system research: An iterative approach to developing affordable systems

    NASA Technical Reports Server (NTRS)

    Watt, Lewis C.; Cannon, Fred S.; Heinsohn, Robert J.; Spaeder, Timothy A.

    1995-01-01

    This paper describes a Strategic Environmental Research and Development Program (SERDP) funded project led jointly by the Marine Corps Multi-Commodity Maintenance Centers, and the Air and Energy Engineering Research Laboratory (AEERL) of the USEPA. The research focuses on paint booth exhaust minimization using recirculation, and on volatile organic compound (VOC) oxidation by the modules of a hybrid air pollution control system. The research team is applying bench, pilot and full scale systems to accomplish the goals of reduced cost and improved effectiveness of air treatment systems for paint booth exhaust.

  9. Effect of air pollutants on the pulmonary surfactant system.

    PubMed

    Müller, B; Seifart, C; Barth, P J

    1998-09-01

    Air pollutants have been recognized to influence the structure and function of the surfactant system. Agents that have received the most attention include ozone, nitrogen dioxide, hyperoxia, diesel exhaust, tobacco smoke, silica and fibrous materials such as asbestos. The deleterious effects of air pollutants on the surfactant system depend on the size of the agent, on its solubility in aqueous solutions and chemical reactivity and on its concentration and the duration of exposure. Hereby the following general rules apply: the smaller the agent's size and the less water soluble the pollutant is, the greater the tendency to reach the alveoli during breathing. In addition, the reactivity also determines the depth of penetration into alveoli. Compounds with high reactivity such as O3, which also fulfil the earlier rules, will react with the upper respiratory tract compared with compounds with slightly reduced reactivity, such as NO2, which will penetrate the alveoli. The common consequence of exposure to air pollutants is an accumulation of surfactant phospholipids and surfactant-specific proteins in the bronchoalveolar lavage fluid. These components also are structurally altered, mainly by oxidant gases, resulting in impairment of their biological activity. Thus, for surfactant phospholipids, there is impaired adsorption to the air-liquid interface due to oxidation of their fatty acids. Also, surfactant protein A, regarded as a modulator of the surfactant system, shows impaired functions after exposure to oxidants. It is likely that in addition to the effects described in this review not all effects are known because the molecular effects of several key components (e.g. SP-B and C) have not been well studied.

  10. Advanced bio-energy systems for Air Force installations

    NASA Astrophysics Data System (ADS)

    Huff, W. J.; Bond, D. H.

    1981-10-01

    This investigation was sponsored by the US Air Force to determine the potential of using innovative biomass energy conversion technology interface with in place energy generating hardware to sustain total annual facility energy requirements on a forested airbase. The investigation found that Eglin AFB, FL, has high potential for such a system, but that certain components and subsystems require test, evaluation and demonstration in an Air Force base environment before full implementation is possible. The investigation found that a biomass energy island system could be achieved through a centralized biomass gasification/combined cycle system to produce 135,000 1b/hr 150 psig steam (saturated) and 27 Mwh/hr electrical power from 1480 green tons of wood chips daily. A phased implementation system is recommended, consisting of separate integrable test and evaluation modules for combined cycle wood gasification and for cogeneration, which would dovetail into an expanded basewide energy self sufficient system. The investigation did not consider harvestation of base woodlands, which is the subject of a separate effort to define the wood resource aspects of a total biomass self-sufficient system.

  11. Capability of air filters to retain airborne bacteria and molds in heating, ventilating and air-conditioning (HVAC) systems.

    PubMed

    Möritz, M; Peters, H; Nipko, B; Rüden, H

    2001-07-01

    The capability of air filters (filterclass: F6, F7) to retain airborne outdoor microorganisms was examined in field experiments in two heating, ventilating and air conditioning (HVAC) systems. At the beginning of the 15-month investigation period, the first filter stages of both HVAC systems were equipped with new unused air filters. The number of airborne bacteria and molds before and behind the filters were determined simultaneously in 14 days-intervals using 6-stage Andersen cascade impactors. Under relatively dry (< 80% R. H.) and warm (> 12 degrees C) outdoor air conditions air filters led to a marked reduction of airborne microorganism concentrations (bacteria by approximately 70% and molds by > 80%). However, during long periods of high relative humidity (> 80% R. H.) a proliferation of bacteria on air filters with subsequent release into the filtered air occurred. These microorganisms were mainly smaller than 1.1 microns therefore being part of the respirable fraction. The results showed furthermore that one possibility to avoid microbial proliferation is to limit the relative humidity in the area of the air filters to 80% R. H. (mean of 3 days), e.g. by using preheaters in front of air filters in HVAC-systems.

  12. New disinfection and sterilization methods.

    PubMed Central

    Rutala, W. A.; Weber, D. J.

    2001-01-01

    New disinfection methods include a persistent antimicrobial coating that can be applied to inanimate and animate objects (Surfacine), a high-level disinfectant with reduced exposure time (ortho-phthalaldehyde), and an antimicrobial agent that can be applied to animate and inanimate objects (superoxidized water). New sterilization methods include a chemical sterilization process for endoscopes that integrates cleaning (Endoclens), a rapid (4-hour) readout biological indicator for ethylene oxide sterilization (Attest), and a hydrogen peroxide plasma sterilizer that has a shorter cycle time and improved efficacy (Sterrad 50). PMID:11294738

  13. Integrated Evaluation of Closed Loop Air Revitalization System Components

    NASA Technical Reports Server (NTRS)

    Murdock, K.

    2010-01-01

    NASA s vision and mission statements include an emphasis on human exploration of space, which requires environmental control and life support technologies. This Contractor Report (CR) describes the development and evaluation of an Air Revitalization System, modeling and simulation of the components, and integrated hardware testing with the goal of better understanding the inherent capabilities and limitations of this closed loop system. Major components integrated and tested included a 4-Bed Modular Sieve, Mechanical Compressor Engineering Development Unit, Temperature Swing Adsorption Compressor, and a Sabatier Engineering and Development Unit. The requisite methodolgy and technical results are contained in this CR.

  14. Investigation of air cleaning system response to accident conditions

    SciTech Connect

    Andrae, R.W.; Bolstad, J.W.; Foster, R.D.; Gregory, W.S.; Horak, H.L.; Idar, E.S.; Martin, R.A.; Ricketts, C.I.; Smith, P.R.; Tang, P.K.

    1980-01-01

    Air cleaning system response to the stress of accident conditions are being investigated. A program overview and hghlight recent results of our investigation are presented. The program includes both analytical and experimental investigations. Computer codes for predicting effects of tornados, explosions, fires, and material transport are described. The test facilities used to obtain supportive experimental data to define structural integrity and confinement effectiveness of ventilation system components are described. Examples of experimental results for code verification, blower response to tornado transients, and filter response to tornado and explosion transients are reported.

  15. Liquid over-feeding air conditioning system and method

    DOEpatents

    Mei, V.C.; Chen, F.C.

    1993-09-21

    A refrigeration air conditioning system utilizing a liquid over-feeding operation is described. A liquid refrigerant accumulator-heat exchanger is placed in the system to provide a heat exchange relationship between hot liquid refrigerant discharged from condenser and a relatively cool mixture of liquid and vaporous refrigerant discharged from the evaporator. This heat exchange relationship substantially sub-cools the hot liquid refrigerant which undergoes little or no evaporation across the expansion device and provides a liquid over-feeding operation through the evaporator for effectively using 100 percent of evaporator for cooling purposes and for providing the aforementioned mixture of liquid and vaporous refrigerant. 1 figure.

  16. Liquid over-feeding air conditioning system and method

    DOEpatents

    Mei, Viung C.; Chen, Fang C.

    1993-01-01

    A refrigeration air conditioning system utilizing a liquid over-feeding operation is described. A liquid refrigerant accumulator-heat exchanger is placed in the system to provide a heat exchange relationship between hot liquid refrigerant discharged from condenser and a relatively cool mixture of liquid and vaporous refrigerant discharged from the evaporator. This heat exchange relationship substantially sub-cools the hot liquid refrigerant which undergoes little or no evaporation across the expansion device and provides a liquid over-feeding operation through the evaporator for effectively using 100 percent of evaporator for cooling purposes and for providing the aforementioned mixture of liquid and vaporous refrigerant.

  17. The Air Force Air Program and Information Management System (APIMS): A flexible tool for managing your Title V Operating Permits

    SciTech Connect

    Weston, A.A.; Gordon, S.R.

    1999-07-01

    The Air Force Command Core System (CCS) is an integrated, activity-based risk management system designed to support the information needs of Environment, Safety, and Occupational Health (ESOH) professionals. These professionals are responsible for managing a complex and often dynamic set of requirements, and therefore, have a need for an information system that can readily be customized to meet their specific needs. This dynamic environment also drives the need for flexibility in the system. The Air Program Information Management System (APIMS) is a module within CCS designed to not only manage permit compliance and emission inventories, but also support the monitoring, recordkeeping, and reporting requirements related to air quality issues. This paper will describe the underlying foundation of CCS, the information linkages within the database, and then summarize the functionality available within the APIMS module to support the Air Quality Managers' information needs, placing emphasis on the flexibility the system provides to manage Title V Operating Permits.

  18. Bioassay and dose measurement in UV disinfection.

    PubMed Central

    Qualls, R G; Johnson, J D

    1983-01-01

    A bioassay method was developed to measure the average intensity within a UV disinfection reactor. The survival of spores of Bacillus subtilis was determined as a function of UV dose to prepare a standard curve. Spores were added to unknown systems, and the survival rate was used to determine the average intensity. A modification was used for flow-through reactors by which spores were injected as a spike and collected at a known time after injection. A point source summation method for calculating intensity was verified by bioassay measurements in a simple cylinder. This calculation method was also applied to multiple-lamp reactors. PMID:6405690

  19. Seed disinfection effect of atmospheric pressure plasma and low pressure plasma on Rhizoctonia solani.

    PubMed

    Nishioka, Terumi; Takai, Yuichiro; Kawaradani, Mitsuo; Okada, Kiyotsugu; Tanimoto, Hideo; Misawa, Tatsuya; Kusakari, Shinichi

    2014-01-01

    Gas plasma generated and applied under two different systems, atmospheric pressure plasma and low pressure plasma, was used to investigate the inactivation efficacy on the seedborne pathogenic fungus, Rhizoctonia solani, which had been artificially introduced to brassicaceous seeds. Treatment with atmospheric plasma for 10 min markedly reduced the R. solani survival rate from 100% to 3% but delayed seed germination. The low pressure plasma treatment reduced the fungal survival rate from 83% to 1.7% after 10 min and the inactivation effect was dependent on the treatment time. The seed germination rate after treatment with the low pressure plasma was not significantly different from that of untreated seeds. The air temperature around the seeds in the low pressure system was lower than that of the atmospheric system. These results suggested that gas plasma treatment under low pressure could be effective in disinfecting the seeds without damaging them.

  20. An augmented reality binocular system (ARBS) for air traffic controllers

    NASA Astrophysics Data System (ADS)

    Fulbrook, Jim E.; Ruffner, John W.; Labbe, Roger

    2008-04-01

    The primary means by which air traffic tower controllers obtain information is through direct out-thewindow viewing, although a considerable amount of time is spent looking at electronic displays and other information sources inside the tower cab. The Air Force Research Laboratory sponsored the development of a prototype Augmented Reality Binocular System (ARBS) that enhances tower controller performance, situation awareness, and safety. The ARBS is composed of a virtual binocular (VB) that displays real-time imagery from high resolution telephoto cameras and sensors mounted on pan/tilt units (PTUs). The selected PTU tracks to the movement of the VB, which has an inertial heading and elevation sensor. Relevant airfield situation text and graphic depictions that identify airfield features are overlaid on the imagery. In addition, the display is capable of labeling and tracking vehicles on which an Automatic Dependent Surveillance - Broadcast (ADS-B) system has been installed. The ARBS provides air traffic controllers and airfield security forces with the capability to orient toward, observe, and conduct continuous airfield operations and surveillance/security missions from any number of viewing aspects in limited visibility conditions. In this paper, we describe the ARBS in detail, discuss the results of a Usability Test of the prototype ARBS, and discuss ideas for follow-on efforts to develop the ARBS to a fieldable level.