Alternative strategies to reduce cost and waste volume in HEPA filtration using metallic filter media - 59348

International Nuclear Information System (INIS)

Chadwick, Chris

2012-01-01

Document available in abstract form only. Full text of publication follows: The disposal costs of contaminated HEPA and THE filter elements have been proved to be disproportionately high compared with the cost of the elements themselves. Work published elsewhere (Moore, et el 1992; Bergman et al 1997) suggests that the cost of use of traditional, panel type, glass fibre HEPA filtration trains to the DOE was, during that period, $29.5 million, based on a five year life cycle, and including installation, testing, removal and disposal life cycle costs being based on estimates dating from 1987-1990. Within that cost estimate, $300 was the value given to the filter and $4, 450 was given to the peripheral activity. Clearly, if the $4, 450 component could be reduced, tremendous saving could ensue, in addition to the reduction of the legacy burden of waste volume. This issue exists for operators in both the US and in Europe. If HEPA filters could be cleaned to a condition where they could either be re-used or decontaminated to the extent that they could be stored as a lower cost wasteform or if HEPA/THE filter elements were available without any organic content likely to give rise to flammable or explosive decomposition gases during long term storage this would also reduce the costs and monitoring necessary in storage. (author)

Investigations into the penetration and pressure drop of HEPA filter media during loading with submicron particle aerosols at high concentrations

International Nuclear Information System (INIS)

Leibold, H; Wilhelm, J.G.

1991-01-01

High Efficiency Particulate Air (HEPA) filters are typically employed in particle removal and retention within the air cleaning systems of clean rooms in the pharmaceutical, nuclear and semiconductor industries for dust concentrations of some μg/m 3 . Their extremely high removal efficiencies for submicron particles make them attractive candidates in complying with increasingly lower emission limits for industrial processes that involve dust concentrations of up to several g/m 3 . Cost-effective operation under such conditions requires the filter units to be recleanable. The recleanability of HEPA filter media depends not only on the operating conditions during the cleaning process but also on the filtration conditions during particle loading. The structure and location of the particles captured by the glass fiber matrix greatly affect the degree to which they can be subsequently dislodged and removed from the filter medium. Changes in filtration efficiency with service time for various particle diameters in the critical submicron size range, as well as the effects of filtration velocity on the increase in pressure drop, are important criteria with regard to recleaning HEPA filter units. Of special significance for the recleanability of HEPA filter media is knowledge of how operating conditions affect dust cake formation. (author)

FULL SCALE REGENERABLE HEPA FILTER DESIGN USING SINTERED METAL FILTER ELEMENTS

International Nuclear Information System (INIS)

Gil Ramos; Kenneth Rubow; Ronald Sekellick

2002-01-01

A Department of Energy funded contract involved the development of porous metal as a HEPA filter, and the subsequent design of a full-scale regenerable HEPA filtration system (RHFS). This RHFS could replace the glass fiber HEPA filters currently being used on the high level waste (HLW) tank ventilation system with a system that would be moisture tolerant, durable, and cleanable in place. The origins of the contract are a 1996 investigation at the Savannah River Technology Center (SRTC) regarding the use of porous metal as a HEPA filter material. This contract was divided into Phases I, IIA and IIB. Phase I of the contract evaluated simple filter cylinders in a simulated High Level Waste (HLW) environment and the ability to clean and regenerate the filter media after fouling. Upon the successful completion of Phase I, Phase IIA was conducted, which included lab scale prototype testing and design of a full-scale system. The work completed under Phase IIA included development of a full-scale system design, development of a filter media meeting the HEPA filtration efficiency that would also be regenerable using prescribed cleaning procedures, and the testing of a single element system prototype at Savannah River. All contract objectives were met. The filter media selected was a nickel material already under development at Mott, which met the HEPA filtration efficiency standard. The Mott nickel media met and exceeded the HEPA requirement, providing 99.99% removal against a requirement of 99.97%. Double open-ended elements of this media were provided to the Savannah River Test Center for HLW simulation testing in the single element prototype filter. These elements performed well and further demonstrated the practicality of a metallic media regenerable HEPA filter system. An evaluation of the manufacturing method on many elements demonstrated the reproducibility to meet the HEPA filtration requirement. The full-scale design of the Mott RHFS incorporated several important

Criteria for calculating the efficiency of HEPA filters during and after design basis accidents

International Nuclear Information System (INIS)

Bergman, W.; First, M.W.; Anderson, W.L.; Gilbert, H.; Jacox, J.W.

1994-12-01

We have reviewed the literature on the performance of high efficiency particulate air (HEPA) filters under normal and abnormal conditions to establish criteria for calculating the efficiency of HEPA filters in a DOE nonreactor nuclear facility during and after a Design Basis Accident (DBA). The literature review included the performance of new filters and parameters that may cause deterioration in the filter performance such as filter age, radiation, corrosive chemicals, seismic and rough handling, high temperature, moisture, particle clogging, high air flow and pressure pulses. The deterioration of the filter efficiency depends on the exposure parameters; in severe exposure conditions the filter will be structurally damaged and have a residual efficiency of 0%. Despite the many studies on HEPA filter performance under adverse conditions, there are large gaps and limitations in the data that introduce significant error in the estimates of HEPA filter efficiencies under DBA conditions. Because of this limitation, conservative values of filter efficiency were chosen when there was insufficient data

A user's evaluation of radial flow HEPA filters

International Nuclear Information System (INIS)

Purcell, J.A.

1992-07-01

High efficiency particulate air (HEPA) filters of rectangular cross section have been used to remove particulates and the associated radioactivity from air ventilation streams since the advent of nuclear materials processing. Use of round axial flow HEPA filters is also longstanding. The advantages of radial flow filters in a circular configuration have been well demonstrated in UKAEA during the last 5--7 years. An evaluation of radial flow filters for fissile process gloveboxes reveals several substantial benefits in addition to the advantages claimed in UKAEA Facilities. The radial flow filter may be provided in a favorable geometry resulting in improved criticality safety. The filter configuration lends to in-place testing at the glovebox to exhaust duct interface. This will achieve compliance with DOE Order 6430.1A, Section 99.0.2. Preliminary testing at SRS for radial flow filters manufactured by Flanders Filters, Inc. revealed compliance in all the usual specifications for filtration efficiency, pressure differential and materials of construction. An evaluation, further detailed in this report, indicates that the radial flow HEPA filter should be considered for inclusion in new ventilation system designs

Effect of age on the structural integrity of HEPA filters

International Nuclear Information System (INIS)

Johnson, J.S.; Beason, D.G.; Smith, P.R.; Gregory, W.S.

1989-01-01

All of the controls on high-efficiency particulate air (HEPA) filters are based on rigid manufacturing standards with regard to filtration efficiency, temperature performance, pressure integrity, and strength. Third-party inspection and testing by the US Department of Energy increases the reliability of new HEPA filters, but only routine in-place testing is used to assure that an aging filter performs adequately. In 1980 the Lawrence Livermore National Laboratory initiated a small evaluation to determine if age has a significant effect on the structural integrity of HEPA filters. A series of used uncontaminated filters dating back to 1965 was obtained for these tests. Tensile strength tests on the old media indicated a decrease in strength. To provide additional measurement of the filters' overall strength, several of these aged filters were subjected to pressure pulses equivalent to the NRC Region I tornado pulses and shock wave over pressures. Data from these tests indicate a decrease in breaking pressure of from 25-50%. A large increase in complete filter pack blow-out during the simulated NRC Region I tornado tests was also observed. The preliminary results indicate the need for an administrative lifetime for HEPA filters used in critical nuclear facilities. Due to the unique conditions in each facility, different administrative lifetimes may be necessary

In Situ Cleanable Alternative HEPA Filter Media

International Nuclear Information System (INIS)

Adamson, D. J.; Terry, M. T.

2002-01-01

The Westinghouse Savannah River Company, located at the Savannah River Site in Aiken, South Carolina, is currently testing two types of filter media for possible deployment as in situ regenerable/cleanable High Efficiency Particulate Air (HEPA) filters. The filters are being investigated to replace conventional, disposable, glass-fiber, HEPA filters that require frequent removal, replacement, and disposal. This is not only costly and subjects site personnel to radiation exposure, but adds to the ever-growing waste disposal problem. The types of filter media being tested, as part of a National Energy Technology Laboratory procurement, are sintered nickel metal and ceramic monolith membrane. These media were subjected to a hostile environment to simulate conditions that challenge the high-level waste tank ventilation systems. The environment promoted rapid filter plugging to maximize the number of filter loading/cleaning cycles that would occur in a specified period of time. The filters were challenged using nonradioactive simulated high-level waste materials and atmospheric dust; materials that cause filter pluggage in the field. The filters are cleaned in situ using an aqueous solution. The study found that both filter media were insensitive to high humidity or moisture conditions and were easily cleaned in situ. The filters regenerated to approximately clean filter status even after numerous plugging and in situ cleaning cycles. Air Techniques International is conducting particle retention testing on the filter media at the Oak Ridge Filter Test Facility. The filters are challenged using 0.3-mm di-octyl phthalate particles. Both the ceramic and sintered media have a particle retention efficiency > 99.97%. The sintered metal and ceramic filters not only can be cleaned in situ, but also hold great potential as a long life alternative to conventional HEPA filters. The Defense Nuclear Facility Safety Board Technical Report, ''HEPA Filters Used in the Department of

Factors Influencing HEPA Filter Performance

International Nuclear Information System (INIS)

Parsons, M.S.; Waggoner, Ch.A.

2009-01-01

Properly functioning HEPA air filtration systems depend on a variety of factors that start with the use of fully characterized challenge conditions for system design and then process control during operation. This paper addresses factors that should be considered during the design phase as well as operating parameters that can be monitored to ensure filter function and lifetime. HEPA filters used in nuclear applications are expected to meet design, fabrication, and performance requirements set forth in the ASME AG-1 standard. The DOE publication Nuclear Air Cleaning Handbook (NACH) is an additional guidance document for design and operation HEPA filter systems in DOE facilities. These two guidelines establish basic maximum operating parameters for temperature, maximum aerosol particle size, maximum particulate matter mass concentration, acceptable differential pressure range, and filter media velocity. Each of these parameters is discussed along with data linking variability of each parameter with filter function and lifetime. Temporal uncertainty associated with gas composition, temperature, and absolute pressure of the air flow can have a direct impact on the volumetric flow rate of the system with a corresponding impact on filter media velocity. Correlations between standard units of flow rate (standard meters per minute or cubic feet per minute) versus actual units of volumetric flow rate are shown for variations in relative humidity for a 70 deg. C to 200 deg. C temperature range as an example of gas composition that, uncorrected, will influence media velocity. The AG-1 standard establishes a 2.5 cm/s (5 feet per minute) ceiling for media velocities of nuclear grade HEPA filters. Data are presented that show the impact of media velocities from 2.0 to 4.0 cm/s media velocities (4 to 8 fpm) on differential pressure, filter efficiency, and filter lifetime. Data will also be presented correlating media velocity effects with two different particle size

Aerosol filtration

International Nuclear Information System (INIS)

First, M.W.; Gilbert, H.

1981-01-01

Significant developments in high efficiency filtration for nuclear applications are reviewed for the period 1968 to 1980. Topics of special interest include factory (bench) and in-place test methods, new developments in paper and filter unit construction methods, vented containment air cleaning systems for LMFBR and light water moderated reactors, and decontamination of offgases from nuclear waste volume reduction processes. It is noted that standards development has been vigorously pursued during this period but that advances in filtration theory have been few. One of the significant changes likely to occur in the immediate future is adoption of the European style of HEPA filters for those that have been in service for the past three decades to obtain the benefits of having almost twice as much filter paper in the same filter cartridge. 71 references

Predicting mass loading as a function of pressure difference across prefilter/HEPA filter systems

International Nuclear Information System (INIS)

Novick, V.J.; Klassen, J.F.; Monson, P.R.

1992-01-01

The purpose of this work is to develop a methodology for predicting the mass loading and pressure drop effects on a prefilter/ HEPA filter system. The methodology relies on the use of empirical equations for the specific resistance of the aerosol loaded filter as a function of the particle diameter. These correlations relate the pressure difference across a filter to the mass loading on the filter and accounts for aerosol particle density effects. These predictions are necessary for the efficient design of new filtration systems and for risk assessment studies of existing filter systems. This work specifically addresses the prefilter/HEPA filter Airborne Activity Confinement Systems (AACS) at the Savannah River Plant. In order to determine the mass loading on the system, it is necessary to establish the efficiency characteristics for the prefilter, the mass loading characteristics of the prefilter measured as a function of pressure difference across the prefilter, and the mass loading characteristics of the HEPA filter as a function of pressure difference across the filter. Furthermore, the efficiency and mass loading characteristics need to be determined as a function of the aerosol particle diameter. A review of the literature revealed that no previous work had been performed to characterize the prefilter material of interest. In order to complete the foundation of information necessary to predict total mass loadings on prefilter/HEPA filter systems, it was necessary to determine the prefilter efficiency and mass loading characteristics. The measured prefilter characteristics combined with the previously determined HEPA filter characteristics allowed the resulting pressure difference across both filters to be predicted as a function of total particle mass for a given particle distribution. These predictions compare favorably to experimental measurements (±25%)

Criteria for calculating the efficiency of deep-pleated HEPA filters with aluminum separators during and after design basis accidents

International Nuclear Information System (INIS)

Bergman, W.; First, M.W.; Anderson, W.L.

1995-01-01

We have reviewed the literature on the performance of HEPA filters under normal and abnormal conditions to establish criteria for calculating the efficiency of HEPA filters in a DOE nonreactor nuclear facility during and after a Design Basis Accident (DBA). This study is only applicable to the standard deep-pleated HEPA filter with aluminum separators as specified in ASME N509[1]. Other HEPA filter designs such as the mini-pleat and separatorless filters are not included in this study. The literature review included the performance of new filters and parameters that may cause deterioration in the filter performance such as filter age, radiation, corrosive chemicals, seismic and rough handling, high temperature, moisture, particle clogging, high air flow and pressure pulses. The deterioration of the filter efficiency depends on the exposure parameters; in severe exposure conditions the filter will be damaged and have a residual efficiency of 0%. There are large gaps and limitations in the data that introduce significant error in the estimates of HEPA filter efficiencies under DBA conditions. Because of this limitation, conservative values of filter efficiency were chosen. The estimation of the efficiency of the HEPA filters under DBA conditions involves three steps: (1) The filter pressure drop and environmental parameters are determined during and after the DBA, (2) Comparing the filter pressure drop to a set of threshold values above which the filter is damaged. There is a different threshold value for each combination of environmental parameters, and (3) Determining the filter efficiency. If the filter pressure drop is greater than the threshold value, the filter is damaged and is assigned 0% efficiency. If the pressure drop is less, then the filter is not damaged and the efficiency is determined from literature values of the efficiency at the environmental conditions

Criteria for calculating the efficiency of deep-pleated HEPA filters with aluminum separators during and after design basis accidents

Energy Technology Data Exchange (ETDEWEB)

Bergman, W.; First, M.W.; Anderson, W.L. [Lawrence Livermore National Laboratory, CA (United States)] [and others

1995-02-01

We have reviewed the literature on the performance of HEPA filters under normal and abnormal conditions to establish criteria for calculating the efficiency of HEPA filters in a DOE nonreactor nuclear facility during and after a Design Basis Accident (DBA). This study is only applicable to the standard deep-pleated HEPA filter with aluminum separators as specified in ASME N509[1]. Other HEPA filter designs such as the mini-pleat and separatorless filters are not included in this study. The literature review included the performance of new filters and parameters that may cause deterioration in the filter performance such as filter age, radiation, corrosive chemicals, seismic and rough handling, high temperature, moisture, particle clogging, high air flow and pressure pulses. The deterioration of the filter efficiency depends on the exposure parameters; in severe exposure conditions the filter will be damaged and have a residual efficiency of 0%. There are large gaps and limitations in the data that introduce significant error in the estimates of HEPA filter efficiencies under DBA conditions. Because of this limitation, conservative values of filter efficiency were chosen. The estimation of the efficiency of the HEPA filters under DBA conditions involves three steps: (1) The filter pressure drop and environmental parameters are determined during and after the DBA, (2) Comparing the filter pressure drop to a set of threshold values above which the filter is damaged. There is a different threshold value for each combination of environmental parameters, and (3) Determining the filter efficiency. If the filter pressure drop is greater than the threshold value, the filter is damaged and is assigned 0% efficiency. If the pressure drop is less, then the filter is not damaged and the efficiency is determined from literature values of the efficiency at the environmental conditions.

Evaluating the Efficiency of Hepatoprotector Hepa Veda in Patients with Liver Pathology

Directory of Open Access Journals (Sweden)

Yu.M. Stepanov

2015-04-01

Full Text Available The article presents the results of efficiency of monotherapy with hepatoprotector Hepa veda in patients with liver pathology. There were found a significant decrease of aminotransferase level in patients with non-alcoholic steatohepatitis and a tendency to decrease in patients with chronic viral hepatitis C that showed the efficiency of this hepatoprotector.

Performance of multiple HEPA filters against plutonium aerosols

International Nuclear Information System (INIS)

Gonzales, M.; Elder, J.; Ettinger, H.

1975-01-01

Performance of multiple stages of High Efficiency Particulate Air (HEPA) filters against aerosols similar to those produced by plutonium processing facilities has been verified as part of an experimental program. A system of three HEPA filters in series was tested against 238 PuO 2 aerosol concentrations as high as 3.3 x 10 10 d/s-m 3 . An air nebulization aerosol generation system, using ball milled plutonium oxide suspended in water, provided test aerosols with size characteristics similar to those defined by a field sampling program at several different AEC plutonium processing facilities. Aerosols have been produced ranging from 0.22 μm activity median aerodynamic diameter (amad) to 1.6 μm amad. The smaller size distributions yield 10 to 30 percent of the total activity in the less than 0.22 μm size range allowing efficiency measurement as a function of size for the first two HEPA filters in series. The low level of activity on the sampler downstream of the third HEPA filter (approximately 0.01 c/s) precludes aerosol size characterization downstream of this filter. For the first two HEPA filters, overall efficiency, and efficiency as a function of size, exceeds 99.98 percent including the <0.12 μm and the 0.12 to 0.22 μm size intervals. Efficiency of the third HEPA filter is somewhat lower with an overall average efficiency of 99.8 percent and an apparent minimum efficiency of 99.5 percent. This apparently lower efficiency is an artifact due to the low level of activity on the sampler downstream of HEPA No. 3 and the variations due to counting statistics. Recent runs with higher concentrations, thereby improving statistical variations, show efficiencies well within minimum requirements. (U.S.)

Filtration approach to mitigate indoor Thoron progeny concentration

International Nuclear Information System (INIS)

Wang, J.; Meisenberg, O.; Karg, E.; Tschiersch, J.; Chen, Y.

2010-01-01

This study investigates filtration of air as potential mitigation method of thoron progeny exposure. The experiments were conducted in a model room (volume 7.1 m 3 ) which was equipped with a pump and an HEPA (high efficiency particulate air) filter. Filtration at a rate of 0.2, 0.4, 0.5 and 0.8 h -1 during 88 h proved an effective practice in reducing the total indoor thoron decay product concentration. The results indicate that 0.4-0.8 h -1 filtration rate had almost the same filtration efficiency in decreasing the total thoron EEC (equilibrium equivalent concentration) by 97% while 80% of total thoron EEC were reduced by 0.2 h -1 filtration rate; meanwhile, the unattached thoron EEC rose significantly by 190, 270, 290%, respectively under 0.4-0.8 h -1 filtration rate, whereas 0.2 h -1 filtration rate increased unattached thoron EEC by 40%. The aerosol number size distribution variation reveals that filtration operation removes smaller particles faster or earlier than the larger ones. The annual effective dose calculated was reduced by 91-92% at a filtration rate of 0.4-0.8 h -1 while 75% reduced at 0.2 h -1 filtration rate after 88 h filtration process. (authors)

Qualification of box HEPA filters for nuclear applications

International Nuclear Information System (INIS)

Bergman, W.; Larsen, G.; Wilson, K.; Rainer, F.

1995-03-01

We have successfully completed qualification tests on high efficiency particulate air (HEPA) filters that are encapsulated within a box and manufactured by American Air Filters. The qualification tests are required by the American Society of Mechanical Engineers Standard ASME N509 and the U.S. Military Standard MIL-F-51068 for HEPA filters to be used in nuclear applications. The qualification tests specify minimum filter efficiencies following exposure to heated air, overpressure, and rough handling. Prior to this study, no box HEPA filters from any manufacturer had been qualified despite their wide-spread use in Department of Energy (DOE) facilities. Box HEPA filters are not addressed in any of the existing HEPA standards and only briefly discussed in the Nuclear Air Cleaning Handbook

Efficient transfection of Xenobiotic Responsive Element-biosensor plasmid using diether lipid and phosphatidylcholine liposomes in differentiated HepaRG cells.

Science.gov (United States)

Demazeau, Maxime; Quesnot, Nicolas; Ripoche, Nicolas; Rauch, Claudine; Jeftić, Jelena; Morel, Fabrice; Gauffre, Fabienne; Benvegnu, Thierry; Loyer, Pascal

2017-05-30

In this study, we evaluated cationic liposomes prepared from diether-NH 2 and egg phosphatidylcholine (EPC) for in vitro gene delivery. The impact of the lipid composition, i.e. the EPC and Diether-NH 2 molar ratio, on in vitro transfection efficiency and cytotoxicity was investigated using the human HEK293T and hepatoma HepaRG cells known to be permissive and poorly permissive cells for liposome-mediated gene transfer, respectively. Here, we report that EPC/Diether-NH 2 -based liposomes enabled a very efficient transfection with low cytotoxicity compared to commercial transfection reagents in both HEK293T and proliferating progenitor HepaRG cells. Taking advantage of these non-toxic EPC/Diether-NH 2 -based liposomes, we developed a method to efficiently transfect differentiated hepatocyte-like HepaRG cells and a biosensor plasmid containing a Xenobiotic Responsive Element and a minimal promoter driving the transcription of the luciferase reporter gene. We demonstrated that the luciferase activity was induced by a canonical inducer of cytochrome P450 genes, the benzo[a]pyrene, and two environmental contaminants, the fluoranthene, a polycyclic aromatic hydrocarbon, and the endosulfan, an organochlorine insecticide, known to induce toxicity and genotoxicity in differentiated HepaRG cells. In conclusion, we established a new efficient lipofection-mediated gene transfer in hepatocyte-like HepaRG cells opening new perspectives in drug evaluation relying on xenobiotic inducible biosensor plasmids. Copyright © 2017 Elsevier B.V. All rights reserved.

Experimental investigation of in situ cleanable HEPA filters

International Nuclear Information System (INIS)

Adamson, D.J.

2000-01-01

Savannah River Technology Center (SRTC), High Level Waste Division, Tanks Focus Area, and the Federal Energy Technology Center (FETC) have been investigating high efficiency particulate air (HEPA) filters which can be regenerated or cleaned in situ as an alternative to conventional disposable HEPA filters. This technical report documents concerns pertaining to conventional HEPA filters

Performance of HEPA filters under severe conditions, 3

International Nuclear Information System (INIS)

Osaki, Makoto; Zanma, Tokugo; Kanagawa, Akira.

1986-01-01

Performance of high efficiency particulate air (HEPA) filters at temperatures from ambient to 240 deg C was measured to prove that HEPA filters kept up their regulated decontamination factor (DF) at elevated temperatures. The DF for NaCl aerosol was measured by using a laser particle spectrometer. Pressure drop of HEPA filters at elevated temperatures was also measured. The DF increased at elevated temperatures. The DF at 200 deg C was an order of magnitude higher than that at ambient. The change of DF at elevated temperatures of various HEPA filters was effectively evaluated by using the ratio of single fiber collection efficiencies at ambient to those at elevated temperatures. Pressure drop of HEPA filters also increased at elevated temperatures. The pressure drop at 200 deg C was 1.3 times larger than that at ambient. The change of DF and pressure drop at elevated temperatures was explained by applying Kirsh's theory to elevated temperatures. (author)

In-place HEPA filter penetration test

International Nuclear Information System (INIS)

Bergman, W.; Wilson, K.; Elliott, J.; Bettencourt, B.; Slawski, J.W.

1997-01-01

We have demonstrated the feasibility of conducting penetration tests on high efficiency particulate air (HEPA) filters as installed in nuclear ventilation systems. The in-place penetration test, which is designed to yield equivalent penetration measurements as the standard DOP efficiency test, is based on measuring the aerosol penetration of the filter installation as a function of particle size using a portable laser particle counter. This in-place penetration test is compared to the current in-place leak test using light scattering photometers for single HEPA filter installations and for HEPA filter plenums using the shroud method. Test results show the in-place penetration test is more sensitive than the in-place leak test, has a similar operating procedure, but takes longer to conduct. Additional tests are required to confirm that the in-place penetration test yields identical results as the standard dioctyl phthalate (DOP) penetration test for HEPA filters with controlled leaks in the filter and gasket and duct by-pass leaks. Further development of the procedure is also required to reduce the test time before the in- place penetration test is practical

Filtration Efficiency of Functionalized Ceramic Foam Filters for Aluminum Melt Filtration

Science.gov (United States)

Voigt, Claudia; Jäckel, Eva; Taina, Fabio; Zienert, Tilo; Salomon, Anton; Wolf, Gotthard; Aneziris, Christos G.; Le Brun, Pierre

2017-02-01

The influence of filter surface chemistry on the filtration efficiency of cast aluminum alloys was evaluated for four different filter coating compositions (Al2O3—alumina, MgAl2O4—spinel, 3Al2O3·2SiO2—mullite, and TiO2—rutile). The tests were conducted on a laboratory scale with a filtration pilot plant, which facilitates long-term filtration tests (40 to 76 minutes). This test set-up allows the simultaneous use of two LiMCAs (before and after the filter) for the determination of the efficiency of inclusion removal. The four tested filter surface chemistries exhibited good thermal stability and mechanical robustness after 750 kg of molten aluminum had been cast. All four filter types exhibited a mean filtration efficiency of at least 80 pct. However, differences were also observed. The highest filtration efficiencies were obtained with alumina- and spinel-coated filter surfaces (>90 pct), and the complete removal of the largest inclusions (>90 µm) was observed. The efficiency was slightly lower with mullite- and rutile-coated filter surfaces, in particular for large inclusions. These observations are discussed in relation to the properties of the filters, in particular in terms of, for example, the surface roughness.

HEPA Filter Vulnerability Assessment

International Nuclear Information System (INIS)

GUSTAVSON, R.D.

2000-01-01

This assessment of High Efficiency Particulate Air (HEPA) filter vulnerability was requested by the USDOE Office of River Protection (ORP) to satisfy a DOE-HQ directive to evaluate the effect of filter degradation on the facility authorization basis assumptions. Within the scope of this assessment are ventilation system HEPA filters that are classified as Safety-Class (SC) or Safety-Significant (SS) components that perform an accident mitigation function. The objective of the assessment is to verify whether HEPA filters that perform a safety function during an accident are likely to perform as intended to limit release of hazardous or radioactive materials, considering factors that could degrade the filters. Filter degradation factors considered include aging, wetting of filters, exposure to high temperature, exposure to corrosive or reactive chemicals, and exposure to radiation. Screening and evaluation criteria were developed by a site-wide group of HVAC engineers and HEPA filter experts from published empirical data. For River Protection Project (RPP) filters, the only degradation factor that exceeded the screening threshold was for filter aging. Subsequent evaluation of the effect of filter aging on the filter strength was conducted, and the results were compared with required performance to meet the conditions assumed in the RPP Authorization Basis (AB). It was found that the reduction in filter strength due to aging does not affect the filter performance requirements as specified in the AB. A portion of the HEPA filter vulnerability assessment is being conducted by the ORP and is not part of the scope of this study. The ORP is conducting an assessment of the existing policies and programs relating to maintenance, testing, and change-out of HEPA filters used for SC/SS service. This document presents the results of a HEPA filter vulnerability assessment conducted for the River protection project as requested by the DOE Office of River Protection

HEPA Help

Science.gov (United States)

Rathey, Allen

2006-01-01

Poor indoor air quality in school facilities can detract from the health and productivity of students, teachers and other employees. Asthma--often triggered or aggravated by dust--is the No. 1 cause of chronic absenteeism in schools. Using vacuum cleaners equipped with high-efficiency particulate air (HEPA) filters to clean education institutions…

In-place HEPA filter penetration test

Energy Technology Data Exchange (ETDEWEB)

Bergman, W.; Wilson, K.; Elliott, J. [Lawrence Livermore National Lab., CA (United States)] [and others

1997-08-01

We have demonstrated the feasibility of conducting penetration tests on high efficiency particulate air (HEPA) filters as installed in nuclear ventilation systems. The in-place penetration test, which is designed to yield equivalent penetration measurements as the standard DOP efficiency test, is based on measuring the aerosol penetration of the filter installation as a function of particle size using a portable laser particle counter. This in-place penetration test is compared to the current in-place leak test using light scattering photometers for single HEPA filter installations and for HEPA filter plenums using the shroud method. Test results show the in-place penetration test is more sensitive than the in-place leak test, has a similar operating procedure, but takes longer to conduct. Additional tests are required to confirm that the in-place penetration test yields identical results as the standard dioctyl phthalate (DOP) penetration test for HEPA filters with controlled leaks in the filter and gasket and duct by-pass leaks. Further development of the procedure is also required to reduce the test time before the in-place penetration test is practical. 14 refs., 14 figs., 3 tabs.

Performance testing of HEPA filters: Progress towards a European standard procedure

Energy Technology Data Exchange (ETDEWEB)

Dyment, J.

1997-08-01

Proposals for a future European testing procedure for {open_quotes}High Efficiency Particulate Air Filters (HEPA and ULPA){close_quotes} are being developed by CEN (Comite Europeen de Normalisation). The new standard will be given the status of national standard in participating countries, conflicting national standards being withdrawn. The standard will comprise 5 parts covering the grouping and classification of HEPA and ULPA filters according to their efficiency, fundamental principles of testing, marking etc (in part 1). Part 2 will cover aerosol production, measurement principles, counting equipment and statistics. Parts 3-5 will cover testing flat sheet media, leak testing of filter elements and the efficiency testing of filter elements respectively. The efficiency test methods allow the use of either homogeneous monodisperse or polydisperse aerosols for the determination of particulate filtration efficiencies as a function of particle size. The particle size at which maximum penetration occurs is first determined in flat sheet media tests; tests on filter elements (constructed using the same filter medium) may be carried out using either a homogeneous monodisperse aerosol of the size at which maximum penetration occurs (MPPS) or a polydisperse aerosol whose median size is close to the MPPS. Tests with monodisperse aerosols may be conducted using condensation nucleus counting equipment; tests using polydisperse test aerosols require the use of optical sizing particle counters. When determining the efficiency of filter elements the downstream aerosol concentrations may be determined from air samples obtained using either an overall method (single point sampling after mixing) or a scan method. The scan method also allows {open_quotes}local{close_quotes} efficiency values to be determined. 1 ref., 1 fig., 1 tab.

Extraction of semivolatile organic compounds from high-efficiency particulate air (HEPA) filters by supercritical carbon dioxide

International Nuclear Information System (INIS)

Schilling, J.B.

1997-09-01

Supercritical fluid extraction (SFE) using unmodified carbon dioxide has been explored as an alternative method for the extraction of semivolatile organic compounds from high-efficiency particulate air (HEPA) filters. HEPA filters provide the final stage of containment on many exhaust systems in US Department of Energy (DOE) facilities by preventing the escape of chemical and radioactive materials entrained in the exhausted air. The efficiency of the filters is tested by the manufacturer and DOE using dioctylphthalate (DOP), a substance regulated by the US Environmental Protection Agency under the Resource Conservation and Recovery Act. Therefore, the filters must be analyzed for semivolatile organics before disposal. Ninety-eight acid, base, and neutral semivolatile organics were spiked onto blank HEPA material and extracted using SFE, Soxhlet, automated Soxhlet, and sonication techniques. The SFE conditions were optimized using a Dionex SFE-703 instrument. Average recoveries for the 98 semivolatile compounds are 82.7% for Soxhlet, 74.0% for sonication, 70.2% for SFE, and 62.9% for Soxtec. Supercritical fluid extraction reduces the extraction solvent volume to 10--15 mL, a factor of 20--30 less than Soxhlet and more than 5 times less than Soxtec and sonication. Extraction times of 30--45 min are used compared to 16--18 h for Soxhlet extraction

Analysis of an MCU HEPA filter

Energy Technology Data Exchange (ETDEWEB)

Peters, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fondeur, F. F. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-01-01

A series of direct analyses on three portions (inlet, center, and outlet) of the High Efficiency Particulate Air (HEPA) filter material from the Modular Caustic-Side Solvent Extraction Unit (MCU) have been performed; this includes x-ray methods such as X-Ray Diffraction (XRD), Contained Scanning Electron Microscopy (CSEM) and X-Ray Fluorescence (XRF), as well as Fourier Transform InfraRed spectroscopy (FTIR). Additionally, two leaching studies (one with water, one with dichloromethane) have been performed on three portions (inlet, center, and outlet) of the HEPA filter material, with the leachates being analyzed by Inductively-coupled plasma emission spectroscopy (ICPES), Semi-Volatile Organic Analysis (SVOA) and gammascan. From the results of the analyses, SRNL feels that cesium-depleted solvent is being introduced into the HEPA filter. The most likely avenue for this is mechanical aerosolization of solvent, where the aerosol is then carried along an airstream into the HEPA filter. Once introduced into the HEPA filter media, the solvent wicks throughout the material, and migrates towards the outlet end. Once on the outlet end, continual drying could cause particulate flakes to exit the filter and travel farther down the airstream path.

HEPA filter concerns - an overview

Energy Technology Data Exchange (ETDEWEB)

Leonard, J.F. [Department of Energy, Washington, DC (United States)

1995-02-01

The U.S. Department of Energy (DOE) recently initiated a complete review of the DOE High Efficiency Particulate Air (HEPA) Filter Program to identify areas for improvement. Although this process is currently ongoing, various issues and problems have already been identified for action that not only impacts the DOE HEPA filter program, but potentially the national and international air cleaning community as well. This paper briefly reviews a few of those concerns that may be of interest, and discusses actions initiated by the DOE to address the associated issues and problems. Issues discussed include: guidance standards, in-place testing, specifications, Test Facilities, portable units, vacuum cleaners, substitute aerosols, filter efficiencies, aging/shelf life/service life, fire suppression, handbook, Quality Products List (QPL), QA testing, and evaluations.

Particle Removal Efficiency of the Portable HEPA Air Cleaner in a Simulated Hospital Ward

DEFF Research Database (Denmark)

Qian, Hua; Li, Yuguo; Sun, Hequan

2010-01-01

of beds in an isolation ward is insufficient. An experiment was conducted in a full scale experimental ward with a dimension of 6.7 m × 6 m × 2.7 m and 6 beds to test these hypotheses for a portable HEPA filter. The removal efficiency for different size particles was measured at different locations...

Degradation of HEPA filters exposed to DMSO

International Nuclear Information System (INIS)

Bergman, W.; Wilson, K.; Larsen, G.; Lopez, R.; LeMay, J.

1994-01-01

Dimethyl sulfoxide (DMSO) sprays are being used to remove the high explosive (HE) from nuclear weapons in the process of their dismantlement. A boxed 50 cfm HEPA filter with an integral prefilter was exposed to DMSO vapor and aerosols that were generated by a spray nozzle to simulate conditions expected in the HE dissolution operation. After 198 hours of operation, the pressure drop of the filter had increased from 1.15 inches to 2.85 inches, and the efficiency for 0.3 μm dioctyl sebacate (DOS) aerosols decreased from 99.992% to 98.6%. Most of the DMSO aerosols had collected as a liquid pool inside the boxed HEPA. The liquid was blown out of the filter exit with 100 cfm air flow at the end of the test. Since the filter still met the minimum allowed efficiency of 99.97% after 166 hours of exposure, we recommend replacing the filter every 160 hours of operation or sooner if the pressure drop increases by 50%. Examination of the filter showed that visible cracks appeared at the joints of the wooden frame and a portion of the sealant had pulled away from the frame. Since all of the DMSO will be trapped in the first HEPA filter, the second HEPA filter should not suffer from DMSO degradation. Thus the combined efficiency for the first filter (98.6%) and the second filter (99.97%) is 99.99996% for 0.3μm particles. If the first filter is replaced prior to its degradation, each of the filters will have 99.97% efficiency, and the combined efficiency will be 99.999991%. The collection efficiency for DMSO/HE aerosols will be much higher because the particle size is much greater

Degradation of HEPA filters exposed to DMSO

Energy Technology Data Exchange (ETDEWEB)

Bergman, W.; Wilson, K.; Larsen, G. [Lawrence Livermore National Laboratory, CA (United States)] [and others

1995-02-01

Dimethyl sulfoxide (DMSO) sprays are being used to remove the high explosive (HE) from nuclear weapons in the process of their dismantlement. A boxed 50 cmf HEPA filter with an integral prefilter was exposed to DMSO vapor and aerosols that were generated by a spray nozzle to simulate conditions expected in the HE dissolution operation. After 198 hours of operation, the pressure drop of the filter had increased form 1.15 inches to 2,85 inches, and the efficiency for 0.3 {mu}m dioctyl sebacate (DOS) aerosols decreased form 99.992% to 98.6%. Most of the DMSO aerosols had collected as a liquid pool inside the boxed HEPA. The liquid was blown out of the filter exit with 100 cmf air flow at the end of the test. Since the filter still met the minimum allowed efficiency of 99.97% after 166 hours of exposure, we recommend replacing the filter every 160 hours of operation or sooner if the pressure drop increases by 50%. Examination of the filter showed that visible cracks appeared at the joints of the wooden frame and a portion of the sealant had pulled away from the frame. Since all of the DMSO will be trapped in the first HEPA filter, the second HEPA filter should not suffer from DMSO degradation. Thus the combined efficiency for the first filter (98.6%) and the second filter (99.97%) is 99.99996% for 0.3 {mu}m particles. If the first filter is replaced prior to its degradation, each of the filters will have 99.97% efficiency, and the combined efficiency will be 99.999991%. The collection efficiency for DMSO/HE aerosols will be much higher because the particle size is much greater.

High Efficiency Particulate Air (HEPA) filters from polyester and polypropylene fibre nonwovens

CSIR Research Space (South Africa)

Boguslavsky, L

2010-10-01

Full Text Available filtration efficiency. Glass fibres are more harmful to human, compared to polypropylene and polyester fibre which are chemically inert. Hydroentanglement and chemical bonding techniques were utilised in manufacturing nonwovens for dry filtration. Acrylic...

Ceramic High Efficiency Particulate Air (HEPA) Filter Final Report CRADA No. TC02160.0

Energy Technology Data Exchange (ETDEWEB)

Mitchell, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bergman, W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-08-25

The technical objective of this project was to develop a ceramic HEPA filter technology, by initially producing and testing coupon ceramics, small scale prototypes, and full scale prototype HEPA filters, and to address relevant manufacturing and commercialization technical issues.

Experience with HEPA filters at United States nuclear installations

International Nuclear Information System (INIS)

Bellamy, R.R.

1977-01-01

Part 50 of Title 10 of the United States Code of Federal Regulations requires that a number of atmosphere cleanup systems be included in the design of commercial nuclear power plants to be licensed in the United States. These filtering systems are to contain high efficiency particulate air (HEPA) filters for removal of radioactive particulate matter generated during normal and accident conditions. Recommendations for the design, testing and maintenance of the filtering systems and HEPA filter components are contained in a number of United States Nuclear Regulatory Commission documents and industry standards. This paper will discuss this published guidance available to designers of filtering systems and the plant operators of U.S. commercial nuclear power plants. The paper will also present a survey of published reports of experience with HEPA filters, failures and possible causes for the failures, and other abnormal occurrences pertaining to HEPA filters installed in U.S. nuclear power installations. A discussion will be included of U.S. practices for qualification of HEPA filters before installation, and verification of continued performance capability at scheduled intervals during operation

Development and evaluation of a HEPA filter for increased strength and resistance to elevated temperature

International Nuclear Information System (INIS)

Gilbert, H.; Bergman, W.; Fretthold, J.K.

1992-01-01

We have developed an improved HEPA filter for increased strength and resistance to elevated temperature to improve the reliability of HEPA filters under accident conditions. The improvements to the HEPA filter consist of a silicone rubber sealant and a new HEPA medium reinforced with a glass cloth. Several prototype filters were built and evaluated for temperature and pressure resistance and resistance to rough handling. The temperature resistance test consisted of exposing the HEPA filter to 1,000 scan at 700 degrees F for five minutes. The pressure resistance test consisted of exposing the HEPA filter to a differential pressure of 10 in. w.g. using a water saturated air flow at 95 degrees F. For the rough handling test, we used a vibrating machine designated the Q110. DOP filter efficiency tests were performed before and after each of the environmental tests. In addition to following the standard practice of using a separate new filter for each environmental test, we also subjected the same filter to the elevated temperature test followed by the pressure resistance test. The efficiency test results show that the improved HEPA filter is significantly better than the standard HEPA filter

Combined use of an electrostatic precipitator and a high-efficiency particulate air filter in building ventilation systems: Effects on cardiorespiratory health indicators in healthy adults.

Science.gov (United States)

Day, D B; Xiang, J; Mo, J; Clyde, M A; Weschler, C J; Li, F; Gong, J; Chung, M; Zhang, Y; Zhang, J

2018-05-01

High-efficiency particulate air (HEPA) filtration in combination with an electrostatic precipitator (ESP) can be a cost-effective approach to reducing indoor particulate exposure, but ESPs produce ozone. The health effect of combined ESP-HEPA filtration has not been examined. We conducted an intervention study in 89 volunteers. At baseline, the air-handling units of offices and residences for all subjects were comprised of coarse, ESP, and HEPA filtration. During the 5-week long intervention, the subjects were split into 2 groups, 1 with just the ESP removed and the other with both the ESP and HEPA removed. Each subject was measured for cardiopulmonary risk indicators once at baseline, twice during the intervention, and once 2 weeks after baseline conditions were restored. Measured indoor and outdoor PM 2.5 and ozone concentrations, coupled with time-activity data, were used to calculate exposures. Removal of HEPA filters increased 24-hour mean PM 2.5 exposure by 38 (95% CI: 31, 45) μg/m 3 . Removal of ESPs decreased 24-hour mean ozone exposure by 2.2 (2.0, 2.5) ppb. No biomarkers were significantly associated with HEPA filter removal. In contrast, ESP removal was associated with a -16.1% (-21.5%, -10.4%) change in plasma-soluble P-selectin and a -3.0% (-5.1%, -0.8%) change in systolic blood pressure, suggesting reduced cardiovascular risks. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Centrifugal Filtration System for Severe Accident Source Term Treatment

Energy Technology Data Exchange (ETDEWEB)

Liu, Shu Chang; Yim, Man Sung [KAIST, Daejeon (Korea, Republic of)

2016-05-15

The objective of this paper is to present the conceptual design of a filtration system that can be used to process airborne severe accident source term. Reactor containment may lose its structural integrity due to over-pressurization during a severe accident. This can lead to uncontrolled radioactive releases to the environment. For preventing the dispersion of these uncontrolled radioactive releases to the environment, several ways to capture or mitigate these radioactive source term releases are under investigation at KAIST. Such technologies are based on concepts like a vortex-like air curtain, a chemical spray, and a suction arm. Treatment of the radioactive material captured by these systems would be required, before releasing to environment. For current filtration systems in the nuclear industry, IAEA lists sand, multi-venturi scrubber, high efficiency particulate arresting (HEPA), charcoal and combinations of the above in NS-G-1-10, 4.143. Most if not all of the requirements of the scenario for applying this technology near the containment of an NPP site and the environmental constraints were analyzed for use in the design of the centrifuge filtration system.

Evaluation of Alternative Control for Prevention and or Mitigation of HEPA Filter Failure Accidents at Tank Farm Facilities

International Nuclear Information System (INIS)

GUSTAVSON, R.D.

2000-01-01

This study evaluates the adequacy and benefit of use of HEPA filter differential pressure limiting setpoints to initiate exhauster shut down as an alternative safety control for postulated accidents that might result in filtration failure and subsequent unfiltered release from Tank Farm primary tank ventilators

Evaluation of the effect of media velocity on HEPA filter performance

International Nuclear Information System (INIS)

Alderman, Steven; Parsons, Michael; Hogancamp, Kristina; Norton, O. Perry; Waggoner, Charles

2007-01-01

Section FC of the ASME AG-1 Code addresses glass fiber HEPA filters and restricts the media velocity to a maximum of 2.54 cm/s (5 ft/min). Advances in filter media technology allow glass fiber HEPA filters to function at significantly higher velocities and still achieve HEPA performance. However, diffusional capture of particles < 100 nm is reduced at higher media velocities due to shorter residence times within the media matrix. Therefore, it is unlikely that higher media velocities for HEPA filters will be allowed without data to demonstrate the effect of media velocity on removal of particles in the smaller size classes. In order to address this issue, static testing has been conducted to generate performance related data and a range of dynamic testing has provided data regarding filter lifetimes, loading characteristics, changes in filter efficiency and the most penetrating particle size over time. Testing was conducted using 31 cm x 31 cm x 29 cm deep pleat HEPA filters supplied from two manufacturers. Testing was conducted at media velocities ranging from 2.0-4.5 cm/s with a solid aerosol challenge composed of potassium chloride. Two set of media velocity data were obtained for each filter type. In one set of evaluations, the maximum aerosol challenge particle size was limited to 3 μm, while particles above 3 μm were not constrained in the second set. This provided for considerable variability in the challenge mass mean diameter and overall mass loading rate. Results of this testing will be provided to the ASME AG-1 FC Committee for consideration in future versions of the HEPA standard. In general, the initial filter efficiency decreased with increasing media velocity. However, initial filter efficiencies were generally good in all cases. Filter efficiency values averaged over the first ten minute of the loading cycle ranged from 99.970 to 99.996 %. Additionally, the most penetrating particle size was observed to decrease with increasing media velocity

Experimental investigation of in situ cleanable HEPA filter

International Nuclear Information System (INIS)

Adamson, D.J.

1999-01-01

The Westinghouse Savannah River Company located at the Savannah River Site (SRS) in Aiken, South Carolina is currently testing the feasibility of developing an in situ cleanable high efficiency particulate air (HEPA) filter system. Sintered metal filters are being tested for regenerability or cleanability in simulated conditions found in a high level waste (HLW) tank ventilation system. The filters are being challenged using materials found in HLW tanks. HLW simulated salt, HLW simulated sludge and South Carolina road dust. Various cleaning solutions have been used to clean the filters in situ. The tanks are equipped with a ventilation system to maintain the tank contents at negative pressure to prevent the release of radioactive material to the environment. This system is equipped with conventional disposable glass-fiber HEPA filter cartridges. Removal and disposal of these filters is not only costly, but subjects site personnel to radiation exposure and possible contamination. A test apparatus was designed to simulate the ventilation system of a HLW tank with an in situ cleaning system. Test results indicate that the Mott sintered metal HEPA filter is suitable as an in situ cleanable or regenerable HEPA filter. Data indicates that high humidity or water did not effect the filter performance and the sintered metal HEPA filter was easily cleaned numerous times back to new filter performance by an in situ spray system. The test apparatus allows the cleaning of the soiled HEPA filters to be accomplished without removing the filters from process. This innovative system would eliminate personnel radiation exposure associated with removal of contaminated filters and the high costs of filter replacement and disposal. The results of these investigations indicate that an in situ cleanable HEPA filter system for radioactive and commercial use could be developed and manufactured

Development and evaluation of a HEPA filter for increased strength and resistance to elevated temperature

International Nuclear Information System (INIS)

Gilbert, H.; Bergman, W.; Fretthold, J.K.

1993-01-01

We have completed a preliminary study of an improved HEPA filter for increased strength and resistance to elevated temperature to improve the reliability of the standard deep pleated HEPA filter under accident conditions. The improvements to the HEPA filter consist of a silicone rubber sealant and a new HEPA medium reinforced with a glass cloth. Three prototype filters were built and evaluated for temperature and pressure resistance and resistance to rough handling. The temperature resistance test consisted of exposing the HEPA filter to 1,000 scan (1,700 m 3 /hr) at 700 degrees F (371 degrees C) for five minutes.The pressure resistance test consisted of exposing the HEPA filter to a differential pressure of 10 in. w.g. (2.5 kPa) using a water saturated air flow at 95 degrees F (35 degrees C). For the rough handling test, we used a vibrating machine designated the Q110. DOP filter efficiency tests were performed before and after each of the environmental tests. In addition to following the standard practice of using a separate new filter for each environmental test, we also subjected the same filter to the elevated temperature test followed by the pressure resistance test. The efficiency test results show that the improved HEPA filter is significantly better than the standard HEPA filter. Further studies are recommended to evaluate the improved HEPA filter and to assess its performance under more severe accident conditions

Efficient filtration system for paraffin-catalyst slurry separation

Directory of Open Access Journals (Sweden)

Khodagholi Mohammad Ali

2013-01-01

Full Text Available The filtration efficiency for separating liquid paraffin (or water from a slurry consisting of 25 weight% spherical alumina in a Slurry Bubble Column Reactor (SBCR comprised of a cylindrical tube of 10 cm diameter and 150 cm length was studied. Various differential pressures (ΔP were applied to two separate tubular sintered metal stainless steel filter elements with nominal pore size of 4 and 16μm. The experimental results disclosed that the rate of filtrations increased on applying higher differential pressure to the filter element. Albeit this phenomenon is limited to moderate ΔPs and for ΔP more than 1 bar is neither harmful nor helpful. The highest filtration rates at ΔPs higher than 1 bar were 170 and 248 ml/minute for 4 and 16μm respectively. Using water as the liquid in slurry the rate of filtration enhanced to 4 folds, and this issue reveals impact of viscosity on filtration efficiency clearly. In all situations, the total amount of particles present in the filtrate part never exceeded a few parts per million (ppm. The statistical analysis of the SEM image of the filtrate indicated that by applying higher pressure difference to the filter element the frequency percent of larger particle size increases. The operation of filter cake removing was performed with back flashing of 300 ml of clean liquid with pressures of 3-5 bar of N2 gas.

Requirements for a cleanable steel HEPA filter derived from a systems analysis

International Nuclear Information System (INIS)

Bergman, W.

1996-06-01

A systems analysis was conducted to determine customer requirements for a cleanable high efficiency particulate air (HEPA) filter in DOE Environmental Management (EM) facilities. The three principal drivers for cleanable steel HEPA are large cost savings, improved filter reliability, and new regulations; they produce a strong incentive to DOE customers to use cleanable steel HEPA filters. Input for customer requirements were obtained from field trips to EM sites and from discussions. Most existing applications require that cleanable steel HEPA filters meet size/performance requirements of standard glass HEPA filters; applications in new facilities can relax size/weight/pressure drop requirements on a case-by-case basis. We then obtained input from commercial firms on availability of cleanable steel HEPA filters. Systems analysis then showed that currently available technology was only able to meet customer needs in a limited number of cases. Further development is needed to meet requirements of EM customers. For cleanable steel HEPA to be retrofitted into existing systems, pressure drop and weight must be reduced. Pressure drop can be reduced by developing steel fiber media from 0.5 μm dia steel fibers. Weight can be reduced by packaging the steel fiber media in one of the standard HEPA configurations. Although most applications will be able to use standard 304 or 316L alloys, an acid resistant alloy such as Hastelloy or Inconel will be needed for incinerator and other thermal processes

Performance of multiple HEPA filters against plutonium aerosols

International Nuclear Information System (INIS)

Gonzales, M.; Elder, J.C.; Tillery, M.I.; Ettinger, H.J.

1976-11-01

Performance of multiple stages of high-efficiency particulate air (HEPA) filters has been verified against plutonium aerosols similar in size characteristics to those challenging the air-cleaning systems of plutonium-processing facilities. An experimental program was conducted to test each filter in systems of three HEPA filters operated in series against 238 PuO 2 aerosols as high as 3.3 x 10 10 dis/s . m 3 in activity concentration and ranging from 0.22 μm to 1.6 μm in activity median aerodynamic diameter (amad). Mean penetration (ratio of downstream to upstream concentration) of each of the three filters in series was below 0.0002, but it apparently increased at each successive filter. Penetration vs size measurements showed that maximum penetration of 238 PuO 2 occurred for sizes between 0.4- and 0.7-μm aerodynamic diameter (D/sub ae/). HEPA filter penetration at half of rated flow differed little from full-flow penetration

Viral Penetration of High Efficiency Particulate Air (HEPA) Filters

Science.gov (United States)

2007-02-01

PVC tubing (Excelon® RNT,US Plastics, Lima , Ohio). Each path runs through a test article and thence through one AGI-30 all-glass impingers (Chemglass...a mechanical flow meter (Blue–White 400, Huntington Beach , California, or PMR1-101346, Cole– Parmer, Vernon Hills, Illinois). At the end of the...fibrous Filters." Air Pollution Control Association 30(4): 377-381. Leenders, G. J. M. and J. H. Stadhouders (1980s). "Effectiveness of HEPA

TECHNICAL BASIS DOCUMENT FOR VENTILATION SYSTEM FILTRATION FAILURE LEADING TO AN UNFILTERED RELEASE

Energy Technology Data Exchange (ETDEWEB)

KOZLOWSKI, S.D.

2005-01-06

This document analyzed three scenarios involving failures of HEPA filtration systems leading to releases from liquid waste tanks. The scenarios are failure due to high temperature (fire), overpressure (filter blowout), and unfiltered release due to filter failure, improper installation. etc.

Mitigation of radon and thoron decay products by filtration

International Nuclear Information System (INIS)

Wang Jin; Meisenberg, Oliver; Chen Yongheng; Karg, Erwin; Tschiersch, Jochen

2011-01-01

Inhalation of indoor radon ( 222 Rn) and thoron ( 220 Rn) decay products is the most important source of exposure to ionizing radiation for the human respiratory tract. Decreasing ventilation rates due to energy saving reasons in new buildings suggest additional active mitigation techniques to reduce the exposure in homes with high radon and thoron concentrations but poor ventilation. Filtration techniques with HEPA filters and simple surgical mask material have been tested for their potential to reduce the indoor exposure in terms of the total effective dose for mixed radon and thoron indoor atmospheres. The tests were performed inside an experimental room providing stable conditions. Filtration (at filtration rates of 0.2 h -1 and larger) removes attached radon and thoron decay products effectively but indoor aerosol as well. Therefore the concentration of unattached decay products (which have a higher dose coefficient) may increase. The decrease of the attached decay product concentrations could be theoretically described by a slowly decreasing exponential process. For attached radon decay products, it exhibited a faster but weaker removal process compared to attached thoron decay products (- 70% for attached radon decay products and - 80% for attached thoron decay products at a filtration rate of 0.5 h -1 with an HEPA filter). The concentration of unattached thoron decay products increased distinctly during the filtration process (+ 300%) while that of unattached radon decay products rose only slightly though at a much higher level (+ 17%). In the theoretical description these observed differences could be attributed to the different half-lives of the nuclides. Considering both effects, reduced attached and increased unattached decay product concentrations, filtration could significantly decrease the total effective dose from thoron whereas the overall effect on radon dose is small. A permanent filtration is recommended because of the slow decrease of the

Measuring of filtration efficiency of nonwoven textiles in volume from scattered light by seeding particles

Directory of Open Access Journals (Sweden)

Sidlof P.

2013-04-01

Full Text Available This paper deals with the method which calculates a filtration efficiency of nonwoven textiles from scattered light intensity by seeding particles. Thefiltration efficiency is commonly measured by particle counters. Samples of liquid or gas are taken during a test in front of and behind a filtration material. The concentration of particles is measured and the filtration efficiency is calculated. The filtration efficiency does not have to be uniform in itswhole surface. The uniformity of filtration is another indicator of a quality of filtration materials. Measurements described in this article were performed on a water filtration setup which enables optical access to the place where the filtration material is mounted. Pictures of illuminated seeding particles are made by a laser sheet and a camera. Visualisation of the filtration process enables measuring of the efficiency of separation versus time and also versus two-dimensional position in case of use of a traverse mechanism. The filtration textiles were tested by 1 μm seeding particles. Mean value of light intensity and number of bright pixels in evaluative areas during image analysis were obtained. On the basis of these data, the filtration efficiency iscalculated. The best image analysis method was chosen.

Structural testing of salt loaded HEPA filters for WIPP

International Nuclear Information System (INIS)

Smith, P.R.; Leslie, I.H.; Hensel, E.C.; Shultheis, T.M.; Walls, J.R.

1993-01-01

The ventilation studies of the Waste Isolation Pilot Plant described in this paper were performed by personnel from New Mexico State Univ. in collaboration with Sandia National Laboratories, Los Alamos National Laboratory and Westinghouse Corporation. High efficiency particulate air filters (0.61m by 0.61m by 0.3m) of the type in use at the Waste Isolation Pilot Plant were loaded with salt aerosol provided from that site. The structural strength of salt-loaded, high-efficiency filters was investigated at two humidity levels, high (75%RH) and low (13-14% RH), by subjecting the filters to pressure transients of the types expected from tornadoes. Filters loaded under the high humidity condition proved to have a greater structural strength than did the filters loaded under the low humidity conditions, when both types were subjected to tornado-like pressure pulses. This unexpected results was apparently due to the crystallization of salt upon the wire face guard of the HEPA filter loaded under the high humidity condition which kept salt from penetrating the filter medium while still providing a substantial pressure drop at the standard flow rate. Results are also presented for HEPA filters pre-conditioned at 100% RH before structural testing and for HEPA filters in series with pre-filters

Filter Paper: Solution to High Self-Attenuation Corrections in HEPA Filter Measurements

International Nuclear Information System (INIS)

Oberer, R.B.; Harold, N.B.; Gunn, C.A.; Brummett, M.; Chaing, L.G.

2005-01-01

An 8 by 8 by 6 inch High Efficiency Particulate Air (HEPA) filter was measured as part of a uranium holdup survey in June of 2005 as it has been routinely measured every two months since 1998. Although the survey relies on gross gamma count measurements, this was one of a few measurements that had been converted to a quantitative measurement in 1998. The measurement was analyzed using the traditional Generalized Geometry Holdup (GGH) approach, using HMS3 software, with an area calibration and self-attenuation corrected with an empirical correction factor of 1.06. A result of 172 grams of 235 U was reported. The actual quantity of 235 U in the filter was approximately 1700g. Because of this unusually large discrepancy, the measurement of HEPA filters will be discussed. Various techniques for measuring HEPA filters will be described using the measurement of a 24 by 24 by 12 inch HEPA filter as an example. A new method to correct for self attenuation will be proposed for this measurement Following the discussion of the 24 by 24 by 12 inch HEPA filter, the measurement of the 8 by 8 by 6 inch will be discussed in detail

Mathematics model of filtration efficiency of moisture separator for nuclear reactors

International Nuclear Information System (INIS)

Zhang Zhenzhong; Jiang Feng; Huang Yunfeng

2010-01-01

In order to study the filtration mechanism of the moisture separator for water droplet of 5∼10μm, this paper set up a physical model. For the mixed meshes, they can be classified into three types: standard meshes, bur meshes and middle meshes. For all fibers of the wire meshes and vertical fibers of standard mixed meshes, a Kuwabara flow field is used to track the particle to get the inertial impaction efficiency and then calculate the total filtration efficiency of the meshes. For other fibers, besides the Kuwabara flow field, an around-flat flow field is added to calculate the efficiency. Lastly, the total efficiency of the moisture separator according to the equation of the filtration efficiency for the filters in series is compared with the experimental data. The result shows that, under the standard condition,the calculation value is consistent with the experimental efficiency data. (authors)

Evaluation of particulate filtration efficiency of retrofit particulate filters for light duty vehicles

International Nuclear Information System (INIS)

Van Asch, R.; Verbeek, R.

2009-10-01

In the light of the currently running subsidy programme for particulate filters in the Netherlands, the Dutch ministry of spatial planning and environment (VROM) asked TNO to execute a desk study to evaluate the particulates filtration efficiency of retrofit particulate filters for light duty vehicles (passenger cars and vans). The typical retrofit particulate filters for light duty vehicles are also called 'open' or 'half-open' filters, because a part of the exhaust gas can pass through the particulate filter unfiltered. From design point they are very different from the majority of the factory installed particulate filters, which are also called wall-flow or 'closed' particulate filters. Due to these differences there is a large difference in filtration efficiency. Whereas the 'dosed' particulate filters show a filtration efficiency of larger than 90%, the filtration efficiency of 'open' particulate filters is generally lower (type approval minimum 30%), and strongly dependent on the conditions of use. The objective of the current project was to assess the average filtration efficiency of retrofit (open) particulate fillters on light duty vehicles in real world day to day driving, based on available literature data. Also, the reasons of a possible deviation with the type approval test results (minimum filtration efficiency of 30%) was investigated.

Experimental relationship between the specific resistance of a HEPA [High Efficiency Particulate Air] filter and particle diameters of different aerosol materials

International Nuclear Information System (INIS)

Novick, V.J.; Monson, P.R.; Ellison, P.E.

1990-01-01

The increase in pressure drop across a HEPA filter has been measured as a function of the particle mass loading using two materials with different particle morphologies. The HEPA filter media chosen, is identical to the filter media used in the Airborne Activity Confinement System (AACS) on the Savannah River Reactors. The velocity through the test filter media was the same as the velocity through the AACS media, under normal operating flow conditions. Sodium Chloride challenge particles were generated using an atomizer, resulting in regularly shaped crystalline forms. Ammonium chloride aerosols were formed from the gas phase reaction of HCl and NH 4 OH vapors resulting in irregular agglomerates. In both cases, the generation conditions were adjusted to provide several different particle size distributions. For each particle size distribution, the mass of material loaded per unit area of filter per unit pressure drop for a given filtration velocity (1/Specific resistance) was measured. Theoretical considerations in the most widely accepted filter cake model predict that the mass per unit area and per unit pressure drop should increase with the particle density times the particle diameter squared. However, these test results indicate that the increase in the mass loaded per unit area per unit pressure drop, for both materials, can be better described by plotting the specific resistance divided by the particle density as an inverse function of the particle density times the particle diameter squared. 9 refs., 7 figs

Ventilation design modifications at Los Alamos Scientific Laboratory major plutonium operational areas

International Nuclear Information System (INIS)

Stafford, R.G.; Gallimore, J.C. Jr.; Mitchell, R.N.; Maraman, W.J.; McNeese, W.D.

1975-01-01

Major ventilation design modifications in plutonium operational areas at Los Alamos have occurred during the past two years. An additional stage of HEPA filters has been added to DP West glove-box process exhaust resulting in significant effluent reductions. The additional stage of HEPA filters is unique in that each filter may be individually DOP tested. Radiological filter efficiencies of each process exhaust stage is presented. DP West room air ventilation systems have been modified to incorporate a single stage of HEPA filters in contrast to a previous American Air Filter PL-24 filtration system. Plutonium effluent reductions of 10 2 to 10 3 have resulted in these new systems. Modified DOP testing procedures for room air filtration systems are discussed. Major plutonium areas of the CMR Building utilizing Aerosolve 95 process exhaust filtration systems have been upgraded with two stages of HEPA filters. Significant reductions in effluent are evident. A unique method of DOP testing each bank of HEPA filters is discussed. Radiological efficiencies of both single and two-stage filters are discussed. (U.S.)

Safety evaluation for packaging (onsite) for the Pacific Northwest National Laboratory HEPA filter box

International Nuclear Information System (INIS)

McCoy, J.C.

1998-01-01

This safety evaluation for packaging (SEP) evaluates and documents the safe onsite transport of eight high-efficiency particulate air (HEPA) filters in the Pacific Northwest National Laboratory HEPA Filter Box from the 300 Area of the Hanford Site to the Central Waste Complex and on to burial in the 200 West Area. Use of this SEP is authorized for 1 year from the date of release

Further development of the cleanable steel HEPA filter, cost/benefit analysis, and comparison with competing technologies

Energy Technology Data Exchange (ETDEWEB)

Bergman, W.; Lopez, R.; Wilson, K. [Lawrence Livermore National Lab., CA (United States)] [and others

1997-08-01

We have made further progress in developing a cleanable steel fiber HEPA filter. We fabricated a pleated cylindrical cartridge using commercially available steel fiber media that is made with 1 {mu}m stainless steel fibers and sintered into a sheet form. Test results at the Department of Energy (DOE) Filter Test Station at Oak Ridge show the prototype filter cartridge has 99.99% efficiency for 0.3 {mu}m dioctyl phthalate (DOP) aerosols and a pressure drop of 1.5 inches. Filter loading and cleaning tests using AC Fine dust showed the filter could be repeatedly cleaned using reverse air pulses. Our analysis of commercially optimized filters suggest that cleanable steel HEPA filters need to be made from steel fibers less than 1{mu}m, and preferably 0.5 {mu}m, to meet the standard HEPA filter requirements in production units. We have demonstrated that 0.5 {mu}m steel fibers can be produced using the fiber bundling and drawing process. The 0.5 {mu}m steel fibers are then sintered into small filter samples and tested for efficiency and pressure drop. Test results on the sample showed a penetration of 0.0015 % at 0.3 {mu}m and a pressure drop of 1.15 inches at 6.9 ft/min (3.5 cm/s) velocity. Based on these results, steel fiber media can easily meet the requirements of 0.03 % penetration and 1.0 inch of pressure drop by using less fibers in the media. A cost analysis of the cleanable steel HEPA filter shows that, although the steel HEPA filter costs much more than the standard glass fiber HEPA filter, it has the potential to be very cost effective because of the high disposal costs of contaminated HEPA filters. We estimate that the steel HEPA filter will save an average of $16,000 over its 30 year life. The additional savings from the clean-up costs resulting from ruptured glass HEPA filters during accidents was not included but makes the steel HEPA filter even more cost effective. 33 refs., 28 figs., 1 tab.

In-situ continuous scanning high efficiency particulate air (HEPA) filter monitoring system

International Nuclear Information System (INIS)

Kirchner, K.N.; Johnson, C.M.; Lucerna, J.J.; Barnett, R.L.

1985-01-01

The testing and replacement of HEPA filters, which are widely used in the nuclear industry to purify process air before it is ventilated to the atmosphere, is a costly and labor-intensive undertaking. Current methods of testing filter performance, such as differential pressure measurement and scanning air monitoring, allow for determination of overall filter performance but preclude detection of symptoms of incipient filter failure, such as small holes in the filters themselves. Using current technology, a continual in-situ monitoring system has been designed which provides three major improvements over current methods of filter testing and replacement. This system (1) realizes a cost savings by reducing the number of intact filters which are currently being replaced unnecessarily, (2) provides a more accurate and quantitative measurement of filter performance than is currently achieved with existing testing methods, and (3) reduces personnel exposure to a radioactive environment by automatically performing most testing operations. The operation and performance of the HEPA filter monitoring system are discussed

Performance of HEPA filters under hot dynamic conditions

International Nuclear Information System (INIS)

Frankum, D.P.; Costigan, G.

1995-01-01

Accidents in nuclear facilities involving fires may have implications upon the ventilation systems where high efficiency particulate air (HEPA) filters are used to minimise the airborne release of radioactive or toxic particles. The Filter Development Section at Harwell Laboratory has been investigating the effect of temperature on the performance of HEPA filters under hot dynamic conditions[ 1 ] for a number of years. The test rig is capable of delivering air flows of 10001/s (at ambient conditions) at temperatures up to 500 degrees C, where measurements of the penetration and pressure drop across the filter are obtained. This paper reports the experiments on different constructions of HEPA filters; rectangular and circular. The filters were tested at an air temperature of 200 degrees C for up to 48 hours at the rated airflow to assess their performance. The penetration measurements for rectangular filters were observed to be below 0.021% after prolonged operation. In a number of cases, holes appeared along the pleat creases of circular filters although the penetration remained below 1%. The sealing gasket for these filters was noted to deform with temperature, permitting a leakage path. A prototype high strength circular filter was evaluated at temperatures of up to 400 degrees C with a penetration less than 0.65%

Performance of HEPA filters under hot dynamic conditions

Energy Technology Data Exchange (ETDEWEB)

Frankum, D.P.; Costigan, G. [AEA Technology, Oxfordshire (United Kingdom)

1995-02-01

Accidents in nuclear facilities involving fires may have implications upon the ventilation systems where high efficiency particulate air (HEPA) filters are used to minimise the airborne release of radioactive or toxic particles. The Filter Development Section at Harwell Laboratory has been investigating the effect of temperature on the performance of HEPA filters under hot dynamic conditions[{sub 1}] for a number of years. The test rig is capable of delivering air flows of 10001/s (at ambient conditions) at temperatures up to 500{degrees}C, where measurements of the penetration and pressure drop across the filter are obtained. This paper reports the experiments on different constructions of HEPA filters; rectangular and circular. The filters were tested at an air temperature of 200{degrees}C for up to 48 hours at the rated airflow to assess their performance. The penetration measurements for rectangular filters were observed to be below 0.021% after prolonged operation. In a number of cases, holes appeared along the pleat creases of circular filters although the penetration remained below 1%. The sealing gasket for these filters was noted to deform with temperature, permitting a leakage path. A prototype high strength circular filter was evaluated at temperatures of up to 400{degrees}C with a penetration less than 0.65%.

Volatility and leachability of heavy metals and radionuclides in thermally treated HEPA filter media generated from nuclear facilities

International Nuclear Information System (INIS)

Yoon, In-Ho; Choi, Wang-Kyu; Lee, Suk-Chol; Min, Byung-Youn; Yang, Hee-Chul; Lee, Kune-Woo

2012-01-01

Highlights: ► Thermally treated HEPA filter media was transformed into glassy bulk materials. ► Main radionuclide and heavy metal were Cs-137 and Zn. ► Cs and Zn were transformed into stable form without volatilization and leaching. ► The proposed technique is simple and energy efficient procedure. - Abstract: The purpose of the present study was to apply thermal treatments to reduce the volume of HEPA filter media and to investigate the volatility and leachability of heavy metals and radionuclides during thermal treatment. HEPA filter media were transformed to glassy bulk material by thermal treatment at 900 °C for 2 h. The most abundant heavy metal in the HEPA filter media was Zn, followed by Sr, Pb and Cr, and the main radionuclide was Cs-137. The volatility tests showed that the heavy metals and radionuclides in radioactive HEPA filter media were not volatilized during the thermal treatment. PCT tests indicated that the leachability of heavy metals and radionuclides was relatively low compared to those of other glasses. XRD results showed that Zn and Cs reacted with HEPA filter media and were transformed into crystalline willemite (ZnO·SiO 2 ) and pollucite (Cs 2 OAl 2 O 3 4SiO 2 ), which are not volatile or leachable. The proposed technique for the volume reduction and transformation of radioactive HEPA filter media into glassy bulk material is a simple and energy efficient procedure without additives that can be performed at relatively low temperature compared with conventional vitrification process.

High-efficiency particulate air (HEPA) filter performance following service and radiation exposure

International Nuclear Information System (INIS)

Jones, L.R.

1975-01-01

Small HEPA filters were exposed to a 60 Co source with a radiation strength of 3 x 10 7 rads per hour and then exposed to steam--air mixtures at several times filter design flow, followed by extended exposure to steam and air at reduced flow. Additional filters were exposed to air flow in a reactor confinement system and then similarly tested with steam--air mixture flows. The test data and calculated effects of filter pluggage with moisture on confinement system performance following potential reactor accidents are described. Gamma radiation exposure impaired the performance of new filters only slightly and temporarily improved performance of service aged filters. Normal confinement system service significantly impaired filter performance although not sufficiently to prevent adequate performance of the SRP confinement system following an unlikely reactor accident. Calculations based on measured filter pluggage indicate that during an accident air flow could be reduced approximately 50 percent with service-degraded HEPA filters present, or approximately 10 percent with new filters damaged by the radiation exposure. (U.S.)

The impact of portable high-efficiency particulate air filters on the incidence of invasive aspergillosis in a large acute tertiary-care hospital.

Science.gov (United States)

Abdul Salam, Zakir-Hussain; Karlin, Rubiyah Binte; Ling, Moi Lin; Yang, Kok Soong

2010-05-01

Worldwide, the frequency of invasive fungal infections has been increasing, with a corresponding increase in the numbers of high-risk patients. Exposure reduction through the use of high-efficiency particulate air (HEPA) filters has been the preferred primary preventive strategy for these high-risk patients. Although the efficiency and benefits of fixed HEPA filters is well proven, the benefits of portable HEPA filters are still inconclusive. This was a retrospective study to assess the impact of 48 portable HEPA filter units deployed in selected wards in Singapore General Hospital, an acute tertiary-care hospital in Singapore. Data were extracted between December 2005 and June 2008 on the diagnoses at discharge and microbiological and histological laboratory findings. All patients with possible, probable, or proven invasive aspergillosis (IA) were included. In wards with portable HEPA filters, the incidence rate of IA of 34.61/100,000 patient-days in the pre-installation period was reduced to 17.51/100,000 patient-days in the post-installation period (P = .01), for an incidence rate ratio of 1.98 (95% confidence interval [CI], 1.10-2.97). In wards with no HEPA filters, there was no significant change in the incidence rate during the study period. Portable HEPA filters were associated with an adjusted odds ratio of 0.49 (95% CI, 0.28-0.85; P = .01), adjusted for diagnosis and length of hospital stay. Portable HEPA filters are effective in the prevention of IA. The cost of widespread portable HEPA filtration in hospitals will be more than offset by the decreases in nosocomial infections in general and in IA in particular. Copyright (c) 2010 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Evaluation of data from HEPA filter quality assurance testing stations

International Nuclear Information System (INIS)

Collins, J.T.; Bellamy, R.R.; Allen, J.R.

1979-01-01

In Revision 1 to Regulatory Guide 1.52, issued in July 1976, the NRC recommended that high efficiency particulate air (HEPA) filters for use in engineered safety features (ESF) atmosphere cleanup systems be visually inspected and dioctylphtalate (DOP) tested at either of two Department of Energy (DOE) operated QA Filter Testing Stations prior to their installation and use in commercial nuclear power plants. This practice was initiated because filter vendors were unable to consistently provide a HEPA filter that would meet the stringent requirements established by DOE and NRC and its predecessor the AEC. In 1977, the NRC staff undertook a program to revise Regulatory Guide 1.52 to reflect recently issued industry standards (e.g., ANSI N509 and N510) and current industry practices. Revision 2 to Regulatory Guide 1.52 was formally issued in March 1978. In conducting this review, the recommendation that HEPA filters, intended for use in ESF systems in commercial nuclear power plants, be routinely tested at the DOE-QA Filter Testing Stations was revaluated. As part of this evluation a detailed analysis of the filter test results recorded by the two QA Testing Stations during the period 1971 to 1977 was conducted. This paper summarizes the results of the analysis and explains the rationale for deleting the requirement that all HEPA filters intended for use in ESF systems be tested at the AQ Testing Station

Potential for HEPA filter damage from water spray systems in filter plenums

Energy Technology Data Exchange (ETDEWEB)

Bergman, W. [Lawrence Livermore National Lab., CA (United States); Fretthold, J.K. [Rocky Flats Safe Sites of Colorado, Golden, CO (United States); Slawski, J.W. [Department of Energy, Germantown, MD (United States)

1997-08-01

The water spray systems in high efficiency particulate air (HEPA) filter plenums that are used in nearly all Department of Energy (DOE) facilities for protection against fire was designed under the assumption that the HEPA filters would not be damaged by the water sprays. The most likely scenario for filter damage involves filter plugging by the water spray, followed by the fan blowing out the filter medium. A number of controlled laboratory tests that were previously conducted in the late 1980s are reviewed in this paper to provide a technical basis for the potential HEPA filter damage by the water spray system in HEPA filter plenums. In addition to the laboratory tests, the scenario for BEPA filter damage during fires has also occurred in the field. A fire in a four-stage, BEPA filter plenum at Rocky Flats in 1980 caused the first three stages of BEPA filters to blow out of their housing and the fourth stage to severely bow. Details of this recently declassified fire are presented in this paper. Although these previous findings suggest serious potential problems exist with the current water spray system in filter plenums, additional studies are required to confirm unequivocally that DOE`s critical facilities are at risk. 22 refs., 15 figs.

Air filtration media from electrospun waste high-impact polystyrene fiber membrane

Science.gov (United States)

Zulfi, Akmal; Miftahul Munir, Muhammad; Hapidin, Dian Ahmad; Rajak, Abdul; Edikresnha, Dhewa; Iskandar, Ferry; Khairurrijal, Khairurrijal

2018-03-01

Nanofiber membranes were synthesized from waste high-impact polystyrene (HIPS) using electrospinning method and then applied as air filtration media. The waste HIPS precursor solution with the concentration of 20 wt.% was prepared by dissolving waste HIPS into the mixture of d-limonene and DMF solvents. Beaded or fine nanofibers could be achieved by adjusting the ratio of solvents mixture (d-limonene and DMF). Using the ratios of solvents (d-limonene: DMF) of 3:1, 1:1, and 1:3, it was obtained beaded HIPS nanofibers with the average diameter of 272 nm, beaded HIPS nanofibers with the average diameter of 937, and fine HIPS nanofibers with the average diameter of 621 nm, respectively. From the FTIR spectral analysis, it was found that the FTIR peaks of the HIPS nanofiber membranes are the same as those of the cleaned waste HIPS and there are no FTIR peaks of DMF and d-limonene solvents. These findings implied that the electrospinning process allows the recycling of waste HIPS into HIPS nanofibers without any trapped solvent phases or apparent degradation of the original material. From the contact angle measurement, it was confirmed that the HIPS nanofiber membranes are hydrophobic and the presence of the beads in the HIPS nanofiber membranes varies their contact angles. From the air-filtration test, it was shown that the fiber morphology (beaded or fine nanofibers) considerably affects the filtration performance of the membranes. The presence of beads increased the distance between the fibers so that the pressure drop decreased. Moreover, the basis weight of the membrane greatly affected the filtration efficiency. The HIPS nanofiber membrane with the basis weight of 12.22 g m‑2 had the efficiency greater than 99.999%, which was equivalent to that of the HEPA filter.

Performance of HEPA filters at LLNL following the 1980 and 1989 earthquakes

International Nuclear Information System (INIS)

Bergman, W.; Elliott, J.; Wilson, K.

1995-01-01

The Lawrence Livermore National Laboratory has experienced two significant earthquakes for which data is available to assess the ability of HEPA filters to withstand seismic conditions. A 5.9 magnitude earthquake with an epicenter 10 miles from LLNL struck on January 24, l980. Estimates of the peak ground accelerations ranged from 0.2 to 0.3 g. A 7.0 magnitude earthquake with an epicenter about 50 miles from LLNL struck on October 17, 1989. Measurements of the ground accelerations at LLNL averaged 0.1 g. The results from the in-place filter tests obtained after each of the earthquakes were compiled and studied to determine if the earthquakes had caused filter leakage. Our study showed that only the 1980 earthquake resulted in a small increase in the number of HEPA filters developing leaks. In the 12 months following the 1980 and 1989 earthquakes, the in-place filter tests showed 8.0% and 4.1% of all filters respectively developed leaks. The average percentage of filters developing leaks from 1980 to 1993 was 3.3%+/-1.7%. The increase in the filter leaks is significant for the 1980 earthquake, but not for the 1989 earthquake. No contamination was detected following the earthquakes that would suggest transient releases from the filtration system

Performance of HEPA filters at LLNL following the 1980 and 1989 earthquakes

Energy Technology Data Exchange (ETDEWEB)

Bergman, W.; Elliott, J.; Wilson, K. [Lawrence Livermore National Laboratory, CA (United States)

1995-02-01

The Lawrence Livermore National Laboratory has experienced two significant earthquakes for which data is available to assess the ability of HEPA filters to withstand seismic conditions. A 5.9 magnitude earthquake with an epicenter 10 miles from LLNL struck on January 24, l980. Estimates of the peak ground accelerations ranged from 0.2 to 0.3 g. A 7.0 magnitude earthquake with an epicenter about 50 miles from LLNL struck on October 17, 1989. Measurements of the ground accelerations at LLNL averaged 0.1 g. The results from the in-place filter tests obtained after each of the earthquakes were compiled and studied to determine if the earthquakes had caused filter leakage. Our study showed that only the 1980 earthquake resulted in a small increase in the number of HEPA filters developing leaks. In the 12 months following the 1980 and 1989 earthquakes, the in-place filter tests showed 8.0% and 4.1% of all filters respectively developed leaks. The average percentage of filters developing leaks from 1980 to 1993 was 3.3%+/-1.7%. The increase in the filter leaks is significant for the 1980 earthquake, but not for the 1989 earthquake. No contamination was detected following the earthquakes that would suggest transient releases from the filtration system.

Testing cleanable/reuseable HEPA prefilters for mixed waste incinerator air pollution control systems

Energy Technology Data Exchange (ETDEWEB)

Burns, D.B.; Wong, A.; Walker, B.W.; Paul, J.D. [Westinghouse Savannah River Co., Aiken, SC (United States)

1997-08-01

The Consolidated Incineration Facility (CIF) at the US DOE Savannah River Site is undergoing preoperational testing. The CIF is designed to treat solid and liquid RCRA hazardous and mixed wastes from site operations and clean-up activities. The technologies selected for use in the air pollution control system (APCS) were based on reviews of existing incinerators, air pollution control experience, and recommendations from consultants. This approach resulted in a facility design using experience from other operating hazardous/radioactive incinerators. In order to study the CIF APCS prior to operation, a 1/10 scale pilot facility, the Offgas Components Test Facility (OCTF), was constructed and has been in operation since late 1994. Its mission is to demonstrate the design integrity of the CIF APCS and optimize equipment/instrument performance of the full scale production facility. Operation of the pilot facility has provided long-term performance data of integrated systems and critical facility components. This has reduced facility startup problems and helped ensure compliance with facility performance requirements. Technical support programs assist in assuring all stakeholders the CIF can properly treat combustible hazardous, mixed, and low-level radioactive wastes. High Efficiency Particulate Air (HEPA) filters are used to remove hazardous and radioactive particulates from the exhaust gas strewn before being released into the atmosphere. The HEPA filter change-out frequency has been a potential issue and was the first technical issue to be studied at the OCTF. Tests were conducted to evaluate the performance of HEPA filters under different operating conditions. These tests included evaluating the impact on HEPA life of scrubber operating parameters and the type of HEPA prefilter used. This pilot-scale testing demonstrated satisfactory HEPA filter life when using cleanable metal prefilters and high flows of steam and water in the offgas scrubber. 8 figs., 2 tabs.

Fundamental study on recovery uranium oxide from HEPA filters

International Nuclear Information System (INIS)

Izumida, T.; Noguchi, Y.

1993-01-01

Large numbers of spent HEPA filters are produced at uranium fuel fabrication facilities. Uranium oxide particles have been collected on these filters. Then, a spent HEPA filter treatment system was developed from the viewpoint of recovering the UO 2 and minimizing the volume. The system consists of a mechanical separation process and a chemical dissolution process. This paper describes the results of fundamental experiments on recovering UO 2 from HEPA filters

Evaluation of environmental filtration control of engineered nanoparticles using the Harvard Versatile Engineered Nanomaterial Generation System (VENGES)

Science.gov (United States)

Echevarría-Vega, Manuel E.; Sotiriou, Georgios A.; Santeufemio, Christopher; Schmidt, Daniel; Demokritou, Philip; Ellenbecker, Michael

2013-01-01

Applying engineering controls to airborne engineered nanoparticles (ENPs) is critical to prevent environmental releases and worker exposure. This study evaluated the effectiveness of two air sampling and six air cleaning fabric filters at collecting ENPs using industrially relevant flame-made engineered nanoparticles generated using a versatile engineered nanomaterial generation system (VENGES), recently designed and constructed at Harvard University. VENGES has the ability to generate metal and metal oxide exposure atmospheres while controlling important particle properties such as primary particle size, aerosol size distribution, and agglomeration state. For this study, amorphous SiO2 ENPs with a 15.4 nm primary particle size were generated and diluted with HEPA-filtered air. The aerosol was passed through the filter samples at two different filtration face velocities (2.3 and 3.5 m/min). Particle concentrations as a function of particle size were measured upstream and downstream of the filters using a specially designed filter test system to evaluate filtration efficiency. Real time instruments (FMPS and APS) were used to measure particle concentration for diameters from 5 to 20,000 nm. Membrane-coated fabric filters were found to have enhanced nanoparticle collection efficiency by 20–46 % points compared to non-coated fabric and could provide collection efficiency above 95 %. PMID:23412707

Evaluation of environmental filtration control of engineered nanoparticles using the Harvard Versatile Engineered Nanomaterial Generation System (VENGES)

International Nuclear Information System (INIS)

Tsai, Candace S.-J.; Echevarría-Vega, Manuel E.; Sotiriou, Georgios A.; Santeufemio, Christopher; Schmidt, Daniel; Demokritou, Philip; Ellenbecker, Michael

2012-01-01

Applying engineering controls to airborne engineered nanoparticles (ENPs) is critical to prevent environmental releases and worker exposure. This study evaluated the effectiveness of two air sampling and six air cleaning fabric filters at collecting ENPs using industrially relevant flame-made engineered nanoparticles generated using a versatile engineered nanomaterial generation system (VENGES), recently designed and constructed at Harvard University. VENGES has the ability to generate metal and metal oxide exposure atmospheres while controlling important particle properties such as primary particle size, aerosol size distribution, and agglomeration state. For this study, amorphous SiO 2 ENPs with a 15.4 nm primary particle size were generated and diluted with HEPA-filtered air. The aerosol was passed through the filter samples at two different filtration face velocities (2.3 and 3.5 m/min). Particle concentrations as a function of particle size were measured upstream and downstream of the filters using a specially designed filter test system to evaluate filtration efficiency. Real time instruments (FMPS and APS) were used to measure particle concentration for diameters from 5 to 20,000 nm. Membrane-coated fabric filters were found to have enhanced nanoparticle collection efficiency by 20–46 % points compared to non-coated fabric and could provide collection efficiency above 95%.

Volatility and leachability of heavy metals and radionuclides in thermally treated HEPA filter media generated from nuclear facilities.

Science.gov (United States)

Yoon, In-Ho; Choi, Wang-Kyu; Lee, Suk-Chol; Min, Byung-Youn; Yang, Hee-Chul; Lee, Kune-Woo

2012-06-15

The purpose of the present study was to apply thermal treatments to reduce the volume of HEPA filter media and to investigate the volatility and leachability of heavy metals and radionuclides during thermal treatment. HEPA filter media were transformed to glassy bulk material by thermal treatment at 900°C for 2h. The most abundant heavy metal in the HEPA filter media was Zn, followed by Sr, Pb and Cr, and the main radionuclide was Cs-137. The volatility tests showed that the heavy metals and radionuclides in radioactive HEPA filter media were not volatilized during the thermal treatment. PCT tests indicated that the leachability of heavy metals and radionuclides was relatively low compared to those of other glasses. XRD results showed that Zn and Cs reacted with HEPA filter media and were transformed into crystalline willemite (ZnO·SiO(2)) and pollucite (Cs(2)OAl(2)O(3)4SiO(2)), which are not volatile or leachable. The proposed technique for the volume reduction and transformation of radioactive HEPA filter media into glassy bulk material is a simple and energy efficient procedure without additives that can be performed at relatively low temperature compared with conventional vitrification process. Copyright © 2012 Elsevier B.V. All rights reserved.

DOE standard: Quality assurance inspection and testing of HEPA filters

International Nuclear Information System (INIS)

1999-02-01

This standard establishes essential elements for the quality assurance inspection and testing of HEPA filters by US Department of Energy (DOE)-accepted Filter Test Facilities (FTF). The standard specifies HEPA filter quality assurance inspection and testing practices established in DOE-STD-3022-98, DOE HEPA Filter Test Program, and provides a basis for the preparation of written operating procedures for primary FTF functions

HEPA air filter (image)

Science.gov (United States)

... pet dander and other irritating allergens from the air. Along with other methods to reduce allergens, such ... controlling the amount of allergens circulating in the air. HEPA filters can be found in most air ...

Multiple HEPA filter test methods, January--December 1976

International Nuclear Information System (INIS)

Schuster, B.; Kyle, T.; Osetek, D.

1977-06-01

The testing of tandem high-efficiency particulate air (HEPA) filter systems is of prime importance for the measurement of accurate overall system protection factors. A procedure, based on the use of an intra-cavity laser particle spectrometer, has been developed for measuring protection factors in the 10 8 range. A laboratory scale model of a filter system was constructed and initially tested to determine individual HEPA filter characteristics with regard to size and state (liquid or solid) of several test aerosols. Based on these laboratory measurements, in-situ testing has been successfully conducted on a number of single and tandem filter installations within the Los Alamos Scientific Laboratory as well as on extraordinary large single systems at Rocky Flats. For the purpose of recovery and for simplified solid waste disposal, or prefiltering purposes, two versions of an inhomogeneous electric field air cleaner have been devised and are undergoing testing. Initial experience with one of the systems, which relies on an electrostatic spraying phenomenon, indicates performance efficiency of greater than 99.9% for flow velocities commonly used in air cleaning systems. Among the effluents associated with nuclear fuel reprocessing is 129 I. An intra-cavity laser detection system is under development which shows promise of being able to detect mixing ratios of one part in 10 7 , I 2 in air

Methods for in-place testing of HEPA and iodine filters used in nuclear power plants

International Nuclear Information System (INIS)

Holmberg, R.; Laine, J.

1978-04-01

The purpose of this work was a general investigation of existing in-place test methods and to build an equipment for in-place testing of HEPA and iodine sorption filters. In this work the discussion is limited to methods used in in-place testing of HEPA and iodine sorption filters used in light-water-cooled reactor plants. Dealy systems, built for the separation of noble gases, and testing of them is not discussed in the work. Contaminants present in the air of a reactor containment can roughly be diveded into three groups: aerosols, reactive gases, and noble gases. The aerosols are filtered with HEPA (High Efficiency Particulate Air) filters. The most important reactive gases are molecular iodine and its two compounds: hydrogen iodide and methyl iodide. Of gases to be removed by the filters methyl iodide is the gas most difficult to remove especially at high relative humidities. Impregnated activated charcoal is generally used as sorption material in the iodine filters. Experience gained from the use of nuclear power plants proves that the function of high efficiency air filter systems can not be considered safe until this is proved by in-place tests. In-place tests in use are basically equal. A known test agent is injected upstream of the filter to be tested. The efficiency is calculated from air samples taken from both sides of the filter. (author)

Use of evidence in 3 local level HEPA policies in Denmark

DEFF Research Database (Denmark)

Jakobsen, Mette Winge; Juel Lau, Cathrine; Skovgaard, Thomas

2013-01-01

of relevant evidence for HEPA, resources as well as organizational structure, culture and capacity. Discussion: Our insight into the actual impact of research in HEPA policy making is still sketchy. However, projects such as REPOPA will help to further our understanding of how research and other kind...... activity (HEPA) policies in 7 countries. This presentation draws on the Danish results of the policy analyses. Focus is on the use and the type of research used in three local level HEPA policies in Denmark. Methods: Three municipal level policies were selected for further investigation. Document analysis...

Performance of HEPA Filter Medium under Accidental Conditions in Nuclear Installations

International Nuclear Information System (INIS)

El-Fawal, M.M.

2011-01-01

High Efficiency Particulate Air filters (HEPA Filters) are the main components in ventilation or confinement system for the retention of radioactive particles in nuclear installations. During abnormal conditions or accidents (e.g. fire accident, criticality in a nuclear fuel cycle facility and LOCA in power reactors) the resulting heat, smoke and humidity affect to a large extent the performance of HEPA filters. As a part of a research programme aims at the evaluation and improvement of the performance of HEPA filter media during abnormal conditions, the effect of elevated temperatures up to 400 degree C on the resistance of medium to penetration of water under pressure has been investigated. The test results showed that the resistance of the medium to penetration of water decreases with increase in temperature and thermal exposure time. This could be attributed to burnout of the organic binder used to improve the resistance of the medium to the penetration of water. The results also showed that at 400 degree C the resistance of the medium to the penetration of water disappeared. This was confirmed by inspection of the filter medium samples after exposure to high temperature using a scanning electron microscope. The inspection of the medium samples showed that the organic binder in the medium was deformed and finally collapsed at 400 degree C. Also, a best estimate model for the relation of filter medium resistance to water penetration under elevated temperature has been implemented. The results of this study can help in establishing a regulatory operating limit conditions (OLCs) for HEPA filter operation at high temperatures conditions in nuclear installations

Performance of HEPA Filter Medium under Accidental Conditions in Nuclear Installations

International Nuclear Information System (INIS)

ElFawal, M.M.

2009-01-01

High Efficiency Particulate Air filters (HEPA Filters) are the main components in ventilation or confinement system for the retention of radioactive particles in nuclear installations. During abnormal conditions or accidents (e.g. fire accident, criticality in a nuclear fuel cycle facility and LOCA in power reactors) the resulting heat, smoke and humidity affect to a large extent the performance of HEPA filters. As a part of a research programme aims at the evaluation and improvement of the performance of HEPA filter media during abnormal conditions, the effect of elevated temperatures up to 400 degree C on the resistance of medium to penetration of water under pressure has been investigated. The test results showed that the resistance of the medium to penetration of water decreases with increase in temperature and thermal exposure time. This could be attributed to burnout of the organic binder used to improve the resistance of the medium to the penetration of water. The results also showed that at 400 degree C the resistance of the medium to the penetration of water disappeared. This was confirmed by inspection of the filter medium samples after exposure to high temperature using a scanning electron microscope. The inspection of the medium samples showed that the organic binder in the medium was deformed and finally collapsed at 400 degree C. Also, a best estimate model for the relation of filter medium resistance to water penetration under elevated temperature has been implemented. The results of this study can help in establishing a regulatory operating limit conditions (OLCs) for HEPA filter operation at high temperatures conditions in nuclear installations.

High efficiency particulate air filter experience survey

International Nuclear Information System (INIS)

Carbaugh, E.H.

1983-01-01

Causes and magnitude of HEPA filter changeouts and failures at DOE sites for the years 1977 to 1979 were evaluated. Conclusions inferred from the data follow: HEPA filters have been generally performing the task they were designed for; most changeouts have been made because of filter plugging, preventive maintenance, or precautionary reasons rather than evidence of filter failure; where failures have been experienced, records generally have not been adequate to determine the cause of failure; where cause of failure has been determined, damage attributed to personnel handling and installation has been substantially more prevalent than that from filter environmental exposure. The need for improved personnel training in handling and installation was stressed. Some reduction in filter failure frequency can be achieved by improving the acid and moisture resistance of filters, and providing adequate pretreatment of air prior to HEPA filtration

Applied patent RFID systems for building reacting HEPA air ventilation system in hospital operation rooms.

Science.gov (United States)

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.

Aerosol filtration

International Nuclear Information System (INIS)

Klein, M.; Goossens, W.R.A.; De Smet, M.; Trine, J.; Hertschap, M.

1984-01-01

This report summarizes the work on the development of fibre metallic prefilters to be placed upstream of HEPA filters for the exhaust gases of nuclear process plants. Investigations at ambient and high temperature were carried out. Measurements of the filtration performance of Bekipor porous webs and sintered mats were performed in the AFLT (aerosol filtration at low temperature) unit with a throughput of 15 m 3 /h. A parametric study on the influence of particle size, fibre diameter, number of layers and superficial velocity led to the optimum choice of the working parameters. Three selected filter types were then tested with polydisperse aerosols using a candle-type filter configuration or a flat-type filter configuration. The small-diameter candle type is not well suited for a spraying nozzles regeneration system so that only the flat-type filter was retained for high-temperature tests. A high-temperature test unit (AFHT) with a throughput of 8 to 10 m 3 /h at 400 0 C was used to test the three filter types with an aerosol generated by high-temperature calcination of a simulated nitric acid waste solution traced with 134 Cs. The regeneration of the filter by spray washing and the effect of the regeneration on the filter performance was studied for the three filter types. The porous mats have a higher dust loading capacity than the sintered web which means that their regeneration frequency can be kept lower

Observations of the distribution and the nature of alpha-active particulate material in a HEPA filter used for plutonium-containing dust

International Nuclear Information System (INIS)

Ryan, M.T.; McDowell, W.J.

1977-02-01

Autoradiography has been used to determine the distribution and the nature of plutonium particulate material on a high-efficiency particulate air (HEPA) filter used to filter 239 Pu-containing dust. Higher concentrations of alpha-active material on upstream and downstream folds of the filter indicate uneven airflow through the filter. Observations of aggregate recoil particles on the downstream face of the filter suggest that aggregate recoil transfer, a mechanism which may reduce long-term HEPA filter efficiency, may be occurring. Amounts of alpha activity found on downstream filters confirm this supposition

A device for uranium series leaching from glass fiber in HEPA filter

International Nuclear Information System (INIS)

Gye-Nam Kim; Hye-Min Park; Wang-Kyu Choi; Jei-Kwon Moon

2012-01-01

For the disposal of a high efficiency particulate air (HEPA) glass filter into the environment, the glass fiber should be leached to lower its radioactive concentration to the clearance level. To derive an optimum method for the removal of uranium series from a HEPA glass fiber, five methods were applied in this study. That is, chemical leaching by a 4.0 M HNO 3 -0.1 M Ce(IV) solution, chemical leaching by a 5 wt% NaOH solution, chemical leaching by a 0.5 M H 2 O 2 -1.0 M Na 2 CO 3 solution, chemical consecutive chemical leaching by a 4.0 M HNO 3 solution, and repeated chemical leaching by a 4.0 M HNO 3 solution were used to remove the uranium series. The residual radioactivity concentrations of 238 U, 235 U, 226 Ra, and 234 Th in glass after leaching for 5 h by the 4.0 M HNO 3 -0.1 M Ce(IV) solution were 2.1, 0.3, 1.1, and 1.2 Bq/g. The residual radioactivity concentrations of 238 U, 235 U, 226 Ra, and 234 Th in glass after leaching for 36 h by 4.0 M HNO 3 -0.1 M Ce(IV) solution were 76.9, 3.4, 63.7, and 71.9 Bq/g. The residual radioactivity concentrations of 238 U, 235 U, 226 Ra, and 234 Th in glass after leaching for 8 h by a 0.5 M H 2 O 2 -1.0 M Na 2 CO 3 solution were 8.9, 0.0, 1.91, and 6.4 Bq/g. The residual radioactivity concentrations of 238 U, 235 U, 226 Ra, and 234 Th in glass after consecutive leaching for 8 h by the 4.0 M HNO 3 solution were 2.08, 0.12, 1.55, and 2.0 Bq/g. The residual radioactivity concentrations of 238 U, 235 U, 226 Ra, and 234 Th in glass after three repetitions of leaching for 3 h by the 4.0 M HNO 3 solution were 0.02, 0.02, 0.29, and 0.26 Bq/g. Meanwhile, the removal efficiencies of 238 U, 235 U, 226 Ra, and 234 Th from the waste solution after its precipitation-filtration treatment with NaOH and alum for reuse of the 4.0 M HNO 3 waste solution were 100, 100, 93.3, and 100%. (author)

Closure of 324 Facility potential HEPA filter failure unreviewed safety questions

International Nuclear Information System (INIS)

Enghusen, M.B.

1997-01-01

This document summarizes the activities which occurred to resolve an Unreviewed Safety Question (USQ) for the 324 Facility [Waste Technology Engineering Laboratory] involving Potential HEPA Filter Breach. The facility ventilation system had the capacity to fail the HEPA filters during accident conditions which would totally plug the filters. The ventilation system fans were modified which lowered fan operating parameters and prevented HEPA filter failures which might occur during accident conditions

Survey of life-cycle costs of glass-paper HEPA filters

International Nuclear Information System (INIS)

Moore, P.; Bergman, W.; Gilbert, H.

1992-08-01

We have conducted a survey of the major users of glass-paper HEPA filters in the DOE complex to ascertain the life cycle costs of these filters. Purchase price of the filters is only a minor portion of the costs; the major expenditures are incurred during the removal and disposal of contaminated filters. Through personal interviews, site visits and completion of questionnaires, we have determined the costs associated with the use of HEPA filters in the DOE complex. The total approximate life-cycle cost for a standard (2 in. x 2 in. x 1 in.) glass-paper HEPA filter is $3,000 for one considered low-level waste (LLW), $11,780 for transuranic (TRU) and $15,000 for high-level waste (HLW). The weighted-average cost for a standard HEPA filter in the complex is $4,753

Penetration of HEPA filters by alpha recoil aerosols

International Nuclear Information System (INIS)

McDowell, W.J.; Seeley, F.G.; Ryan, M.T.

1976-01-01

The self-scattering of alpha-active substances has long been recognized and is attributed to expulsion of aggregates of atoms from the surface of alpha-active materials by alpha emission recoil energy, and perhaps to further propulsion of these aggregates by subsequent alpha recoils. Workers at the University of Lowell recently predicted that this phenomenon might affect the retention of alpha-active particulate matter by HEPA filters, and found support in experiments with 212 Pb. Tests at Oak Ridge National Laboratory have confirmed that alpha-emitting particulate matter does penetrate high-efficiency filter media, such as that used in HEPA filters, much more effectively than do non-radioactive or beta-gamma active aerosols. Filter retention efficiencies drastically lower than the 99.9 percent quoted for ordinary particulate matter were observed with 212 Pb, 253 Es, and 238 Pu sources, indicating that the phenomenon is common to all of these and probably to all alpha-emitting materials of appropriate half-life. Results with controlled air-flow through filters in series are consistent with the picture of small particles dislodged from the ''massive'' surface of an alpha-active material, and then repeatedly dislodged from positions on the filter fibers by subsequent alpha recoils. The process shows only a small dependence on the physical form of the source material. Oxide dust, nitrate salt, and plated metal all seem to generate the recoil particles effectively. The amount penetrating a series of filters depends on the total amount of activity in the source material, its specific activity, and the length of time of air flow

Improved HEPA Filter Technology for Flexible and Rigid Containment Barriers

International Nuclear Information System (INIS)

Pinson, Paul Arthur

1998-01-01

Safety and reliability in glovebox operations can be significantly improved and waste packaging efficiencies can be increased by inserting flexible, lightweight, high capacity HEPA filters into the walls of plastic sheet barriers. This HEPA filter/barrier technology can be adapted to a wide variety of applications: disposable waste bags, protective environmental barriers for electronic equipment, single or multiple use glovebag assemblies, flexible glovebox wall elements, and room partitions. These reliable and inexpensive filtered barriers have many uses in fields such as radioactive waste processing, HVAC filter changeout, vapor or grit blasting, asbestos cleanup, pharmaceutical, medical, biological, and electronic equipment containment. The applications can result in significant cost savings, improved operational reliability and safety, and total waste volume reduction. This technology was developed at the Argonne National Laboratory-West (ANL-W) in 1993 and has been used at ANL-W since then at the TRU Waste Characterization Chamber Gloveboxes. Another 1998 AGS Conference paper titled ''TRU Waste Characterization Gloveboxes'', presented by Mr. David Duncan of ANL-W, describes these boxes

Behavior of HEPA filters under high humidity airflows

International Nuclear Information System (INIS)

Ricketts, C.I.

1992-10-01

To help determine and improve the safety margins of High Efficiency Particulate Air (HEPA) filter units in nuclear facilities under possible accident conditions, the structural limits and failure mechanisms of filter in high-humidity airflows were established and the fundamental physical phenomena underlying filter failure or malfunction in humid air were identified. Empirical models for increases in filter pressure drop with time in terms of the relevant airstream parameters were also developed. The weaknesses of currently employed humidity countermeasures used in filter protection are discussed and fundamental explanations for reported filter failures in normal service are given. (orig./DG) [de

Enhanced filtration: progress report, July--September 1976

International Nuclear Information System (INIS)

Nelson, G.O.; Miller, B.H.; Richards, C.P.; Biermann, A.H.

1977-01-01

A theoretical and experimental investigation of non-ionizing electrostatic air filters is presented. These filters are designed to be used as prefilters to aid the HEPA filters currently used in nuclear facilities. Parameters that affect the filter efficiency and a theory that describes the increase in filter efficiency and pressure drop as the filter is loaded with particles are discussed

Multiple HEPA filter test methods. Progress report, January--December 1977

International Nuclear Information System (INIS)

Schuster, B.; Kyle, T.; Osetek, D.

1978-09-01

Tandem high-efficiency particulate air (HEPA) filter efficiency measurements have been successfully performed on a large number of 20,000 CFM installations. The testing procedure relies on the use of a laser intracavity particle spectrometer and a very high-volume thermal dioctyl phthalate aerosol generator designed and constructed specifically for this purpose. For systems that cannot be tested in this fashion, work has been initiated on the generation and detection of a fluorescent self-identifying aerosol to eliminate the background problem. General candidate aerosols and methods to disperse them have been uncovered. Two distinct detection concepts have evolved for the measurement of size and concentration of these particles

A review of DOE HEPA filter component test activities

Energy Technology Data Exchange (ETDEWEB)

Slawski, J.W.; Bresson, J.F. [Informatics Corp., Inc., Albuquerque, NM (United States); Scripsick, R.C. [Los Alamos National Lab., NM (United States)

1997-08-01

All HEPA filters purchased for installation in DOE nuclear facilities are required to be tested at a Filter Test Facility (FTF) prior to installation. The number of HEPA filters purchased by DOE has been reduced so much that the Hanford FTF was closed. From Fiscal Year (FY) 1992 to 1994, funding was not provided to the FTF Technical Support Group (TSG) at the Los Alamos National Laboratory. As a consequence, Round Robin Tests (RRTs), performed twice each year by the FTFs to assess constituency of test results among the FTFs, were not performed in FY 1992 and FY 1993. The Annual Reports of FTF test activities were not prepared for FY 1992 - 1995. Technical support provided to the FTFs was minimal. There is talk of closing a second FTF, and ongoing discussions as to whether DOE will continue to fund operation of the FTFs. In FY 1994, DOE Defense Programs commenced funding the TSG. RRT data for FY 1994 and 1995 have been entered into the database; the FY 1994 RRT report has been issued; and the FY 1995 RRT report is in progress. Data from semiannual reports have been retrieved and entered into the database. Standards related to HEPA filter test and procurement activities are now scheduled for issuance by FY 1996. Continuation of these activities depends on whether DOE will continue to support the HEPA filter test program. The history and activities of the FTFs and the TSG at Los Alamos have been reported at previous Air Cleaning Conferences. Data from the FY 1991 Annual Report of FTF activities was presented at the 1992 Air Cleaning Conference. Preparation of the Annual Reports was temporarily suspended in 1992. However, all of the FTF Semiannual report data have been retrieved and entered into the data base. This paper focuses primarily on the results of HEPA filter tests conducted by FTFs during FY 1992 - FY 1995, and the possible effects of the DOE program uncertainties on the quality of HEPA filters for installation at the DOE sites. 15 refs., 13 tabs.

Use of sulfuric-nitric acid for the recovery of plutonium from HEPA filters. (620.2, WH001/LWE)

International Nuclear Information System (INIS)

Clark, D.E.

1978-09-01

Contaminated high-efficiency particulate air (HEPA) filter media, containing PuO 2 powder which had been calcined at 700 0 C, were treated with concentrated H 2 SO 4 -HNO 3 at 190 to 200 0 C for periods ranging from 0.5 to 2.0 hours. When followed by a dilute HNO 3 rinse, this treatment was shown to be very effective as a plutonium recovery operation (approximately greater than 97% of the plutonium was solubilized). A proposed treatment scheme is given which could provide both a plutonium recovery option for HEPA filters and a reduction in overall waste volume

Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems.

Science.gov (United States)

Ng, Bing Feng; Xiong, Jin Wen; Wan, Man Pun

2017-01-01

The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV) systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency.

Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV systems.

Directory of Open Access Journals (Sweden)

Bing Feng Ng

Full Text Available The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency.

Effluent Scrubbing of Engine Exhaust of a Nuclear Thermal Propulsion Engine

Data.gov (United States)

National Aeronautics and Space Administration — The Institute for Clean Energy Technology (ICET) at MSU already supports long-standing high-efficiency nuclear particulate air (HEPA) filtration research as well as...

Remote aerosol testing of large size HEPA filter banks

International Nuclear Information System (INIS)

Franklin, B.; Pasha, M.; Bronger, C.A.

1987-01-01

Different methods of testing HEPA filter banks are described. Difficulties in remote testing of large banks of HEPA filters in series with minimum distances between banks, and with no available access upstream and downstream of the filter house, are discussed. Modifications incorporated to make the filter system suitable for remote testing without personnel re-entry into the filter house are described for a 51,000 m/sup 3//hr filter unit at the WIPP site

Efficiency and safety of leukocyte filtration during cardiopulmonary bypass for cardiac surgery

NARCIS (Netherlands)

Smit, JJJ; de Vries, AJ; Gu, YJ; van Oeveren, W

Background. Leukocyte filtration of systemic blood during cardiopulmonary bypass surgery to reduce post-operative morbidity has not yet been established because of the enormous leukocyte release from the third space. This study was designed to examine the efficiency and safety of leukocyte

Study of the effect of humidity, particle hygroscopicity and size on the mass loading capacity of HEPA filters

International Nuclear Information System (INIS)

Gupta, A.

1992-01-01

The effect of humidity, particle hygroscopicity and size on the mass loading capacity of glass fiber HEPA filters has been studied. At humidifies above the deliquescent point, the pressure drop across the HEPA filter increased non-linearly with the areal loading density (mass collected/filtration area) of NaCl aerosol, thus significantly reducing the mass loading capacity of the filter compared to dry hygroscopic or non-hygroscopic particle mass loadings. The specific cake resistance, K 2 , has been computed for different test conditions and used as a measure of the mass loading capacity. K. was found to decrease with increasing humidity for the non-hygroscopic aluminum oxide particles and the hygroscopic NaCl particles (at humidities below the deliquescent point). It is postulated that an increase in humidity leads to the formation of a more open particulate cake which lowers the pressure drop for a given mass loading. A formula for predicting K 2 for lognormally distributed aerosols (parameters obtained from impactor data) is derived. The resistance factor, R, calculated using this formula was compared to the theoretical R calculated using the Rudnick-Happel expression. For the non-hygroscopic aluminum oxide the agreement was good but for the hygroscopic sodium chloride, due to large variation in the cake porosity estimates, the agreement was poor

ASME AG-1 Section FC Qualified HEPA Filters; a Particle Loading Comparison - 13435

International Nuclear Information System (INIS)

Stillo, Andrew; Ricketts, Craig I.

2013-01-01

High Efficiency Particulate Air (HEPA) Filters used to protect personnel, the public and the environment from airborne radioactive materials are designed, manufactured and qualified in accordance with ASME AG-1 Code section FC (HEPA Filters) [1]. The qualification process requires that filters manufactured in accordance with this ASME AG-1 code section must meet several performance requirements. These requirements include performance specifications for resistance to airflow, aerosol penetration, resistance to rough handling, resistance to pressure (includes high humidity and water droplet exposure), resistance to heated air, spot flame resistance and a visual/dimensional inspection. None of these requirements evaluate the particle loading capacity of a HEPA filter design. Concerns, over the particle loading capacity, of the different designs included within the ASME AG-1 section FC code[1], have been voiced in the recent past. Additionally, the ability of a filter to maintain its integrity, if subjected to severe operating conditions such as elevated relative humidity, fog conditions or elevated temperature, after loading in use over long service intervals is also a major concern. Although currently qualified HEPA filter media are likely to have similar loading characteristics when evaluated independently, filter pleat geometry can have a significant impact on the in-situ particle loading capacity of filter packs. Aerosol particle characteristics, such as size and composition, may also have a significant impact on filter loading capacity. Test results comparing filter loading capacities for three different aerosol particles and three different filter pack configurations are reviewed. The information presented represents an empirical performance comparison among the filter designs tested. The results may serve as a basis for further discussion toward the possible development of a particle loading test to be included in the qualification requirements of ASME AG-1

ASME AG-1 Section FC Qualified HEPA Filters; a Particle Loading Comparison - 13435

Energy Technology Data Exchange (ETDEWEB)

Stillo, Andrew [Camfil Farr, 1 North Corporate Drive, Riverdale, NJ 07457 (United States); Ricketts, Craig I. [New Mexico State University, Department of Engineering Technology and Surveying Engineering, P.O. Box 30001 MSC 3566, Las Cruces, NM 88003-8001 (United States)

2013-07-01

High Efficiency Particulate Air (HEPA) Filters used to protect personnel, the public and the environment from airborne radioactive materials are designed, manufactured and qualified in accordance with ASME AG-1 Code section FC (HEPA Filters) [1]. The qualification process requires that filters manufactured in accordance with this ASME AG-1 code section must meet several performance requirements. These requirements include performance specifications for resistance to airflow, aerosol penetration, resistance to rough handling, resistance to pressure (includes high humidity and water droplet exposure), resistance to heated air, spot flame resistance and a visual/dimensional inspection. None of these requirements evaluate the particle loading capacity of a HEPA filter design. Concerns, over the particle loading capacity, of the different designs included within the ASME AG-1 section FC code[1], have been voiced in the recent past. Additionally, the ability of a filter to maintain its integrity, if subjected to severe operating conditions such as elevated relative humidity, fog conditions or elevated temperature, after loading in use over long service intervals is also a major concern. Although currently qualified HEPA filter media are likely to have similar loading characteristics when evaluated independently, filter pleat geometry can have a significant impact on the in-situ particle loading capacity of filter packs. Aerosol particle characteristics, such as size and composition, may also have a significant impact on filter loading capacity. Test results comparing filter loading capacities for three different aerosol particles and three different filter pack configurations are reviewed. The information presented represents an empirical performance comparison among the filter designs tested. The results may serve as a basis for further discussion toward the possible development of a particle loading test to be included in the qualification requirements of ASME AG-1

Novel antimony doped tin oxide/carbon aerogel as efficient electrocatalytic filtration membrane

Directory of Open Access Journals (Sweden)

Zhimeng Liu

2016-05-01

Full Text Available A facile method was developed to prepare antimony doped tin oxide (Sb-SnO2/carbon aerogel (CA for use as an electrocatalytic filtration membrane. The preparation process included synthesis of a precursor sol, impregnation, and thermal decomposition. The Sb-SnO2, which was tetragonal in phase with an average crystallite size of 10.8 nm, was uniformly distributed on the CA surface and firmly attached via carbon-oxygen-tin chemical bonds. Preliminary filtration tests indicated that the Sb-SnO2/CA membrane had a high rate of total organic carbon removal for aqueous tetracycline owing to its high current efficiency and electrode stability.

Advanced nuclear precleaner

Energy Technology Data Exchange (ETDEWEB)

Wright, S.R. [InnovaTech, Inc., Durham, NC (United States)

1997-10-01

This Phase II Small Business Innovation Research (SBIR) program`s goal is to develop a dynamic, self-cleaning air precleaner for high-efficiency particulate air (HEPA) filtration systems that would extend significantly the life of HEPA filter banks by reducing the particulate matter that causes filter fouling and increased pack pressure. HEPA filters are widely used in DOE, Department of Defense, and a variety of commercial facilities. InnovaTech, Inc. (Formerly Micro Composite materials Corporation) has developed a proprietary dynamic separation device using a concept called Boundary Layer Momentum Transfer (BLMT) to extract particulate matter from fluid process streams. When used as a prefilter in the HVAC systems or downstream of waste vitrifiers in nuclear power plants, fuel processing facilities, and weapons decommissioning factories, the BLMT filter will dramatically extend the service life and increase the operation efficiency of existing HEPA filtration systems. The BLMT filter is self cleaning, so there will be no degraded flow or increased pressure drop. Because the BLMT filtration process is independent of temperature, it can be designed to work in ambient, medium, or high-temperature applications. During Phase II, the authors are continuing development of the computerized flow simulation model to include turbulence and incorporate expansion into a three-dimensional model that includes airflow behavior inside the filter housing before entering the active BLMT device. A full-scale (1000 ACFM) prototype filter is being designed to meet existing HEPA filter standards and will be fabricated for subsequent testing. Extensive in-house testing will be performed to determine a full range of performance characteristics. Final testing and evaluation of the prototype filter will be conducted at a DOE Quality Assurance Filter Test Station.

Advanced nuclear precleaner

International Nuclear Information System (INIS)

Wright, S.R.

1997-01-01

This Phase II Small Business Innovation Research (SBIR) program's goal is to develop a dynamic, self-cleaning air precleaner for high-efficiency particulate air (HEPA) filtration systems that would extend significantly the life of HEPA filter banks by reducing the particulate matter that causes filter fouling and increased pack pressure. HEPA filters are widely used in DOE, Department of Defense, and a variety of commercial facilities. InnovaTech, Inc. (Formerly Micro Composite materials Corporation) has developed a proprietary dynamic separation device using a concept called Boundary Layer Momentum Transfer (BLMT) to extract particulate matter from fluid process streams. When used as a prefilter in the HVAC systems or downstream of waste vitrifiers in nuclear power plants, fuel processing facilities, and weapons decommissioning factories, the BLMT filter will dramatically extend the service life and increase the operation efficiency of existing HEPA filtration systems. The BLMT filter is self cleaning, so there will be no degraded flow or increased pressure drop. Because the BLMT filtration process is independent of temperature, it can be designed to work in ambient, medium, or high-temperature applications. During Phase II, the authors are continuing development of the computerized flow simulation model to include turbulence and incorporate expansion into a three-dimensional model that includes airflow behavior inside the filter housing before entering the active BLMT device. A full-scale (1000 ACFM) prototype filter is being designed to meet existing HEPA filter standards and will be fabricated for subsequent testing. Extensive in-house testing will be performed to determine a full range of performance characteristics. Final testing and evaluation of the prototype filter will be conducted at a DOE Quality Assurance Filter Test Station

Behavior of the polygonal HEPA filter exposed to water droplets carried by the offgas flow

International Nuclear Information System (INIS)

Jannakos, K.; Potgeter, G.; Legner, W.

1991-01-01

A polygonal high-efficiency particulate air (HEPA) filter element has been developed and tested with a view to cleaning the dissolver offgas from reprocessing plants. It is likewise suited to filter process offgases generated in other plants. Due to its high dew point (about 30 degree C) the dissolver offgas, before being directed into the HEPA filter, is heated with a gas heater to approx. 100 degree C so that condensation in the pipework upstream of the filter and in the filter proper is avoided. In case of failure of the heater the offgas may undergo condensation upstream of the HEPA filter until it is bypassed to a standby heater or a standby filter system. Consequently, the filter may be loaded with water droplets. therefore, experiments have been performed with a view to estimating the behavior of the polygonal filter element when exposed to condensate droplets in a real plant. According to the experiments performed so far it can be anticipated that in case of failure of the heater the amount of condensate produced until bypassing to a standby system will not damage a new or little loaded polygonal filter element. The experiments will be carried on with the goal of investigating the behavior of a heavily loaded polygonal filter element exposed to water droplets

Multi-Canister overpack internal HEPA filters

International Nuclear Information System (INIS)

SMITH, K.E.

1998-01-01

The rationale for locating a filter assembly inside each Multi-Canister Overpack (MCO) rather than include the filter in the Cold Vacuum Drying (CVD) process piping system was to eliminate the potential for contamination to the operators, processing equipment, and the MCO. The internal HEPA filters provide essential protection to facility workers from alpha contamination, both external skin contamination and potential internal depositions. Filters installed in the CVD process piping cannot mitigate potential contamination when breaking the process piping connections. Experience with K-Basin material has shown that even an extremely small release can result in personnel contamination and costly schedule disruptions to perform equipment and facility decontamination. Incorporating the filter function internal to the MCO rather than external is consistent with ALARA requirements of 10 CFR 835. Based on the above, the SNF Project position is to retain the internal HEPA filters in the MCO design

Electrospun Magnetic Nanoparticle-Decorated Nanofiber Filter and Its Applications to High-Efficiency Air Filtration.

Science.gov (United States)

Kim, Juyoung; Chan Hong, Seung; Bae, Gwi Nam; Jung, Jae Hee

2017-10-17

Filtration technology has been widely studied due to concerns about exposure to airborne dust, including metal oxide nanoparticles, which cause serious health problems. The aim of these studies has been to develop mechanisms for the continuous and efficient removal of metal oxide dusts. In this study, we introduce a novel air filtration system based on the magnetic attraction force. The filtration system is composed of a magnetic nanoparticle (MNP)-decorated nanofiber (MNP-NF) filter. Using a simple electrospinning system, we fabricated continuous and smooth electrospun nanofibers with evenly distributed Fe 3 O 4 MNPs. Our electrospun MNP-NF filter exhibited high particle collection efficiency (∼97% at 300 nm particle size) compared to the control filter (w/o MNPs, ∼ 68%), with a ∼ 64% lower pressure drop (∼17 Pa) than the control filter (∼27 Pa). Finally, the filter quality factors of the MNP-NF filter were 4.7 and 11.9 times larger than those of the control filter and the conventional high-efficiency particulate air filters (>99% and ∼269 Pa), respectively. Furthermore, we successfully performed a field test of our MNP-NF filter using dust from a subway station tunnel. This work suggests that our novel MNP-NF filter can be used to facilitate effective protection against hazardous metal oxide dust in real environments.

Health hazards associated with the use of di-(2-ethylhexyl) phthalate (commonly referred to as DOP) in HEPA filter test

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-01-01

Di-(2-ethylhexyl) phthalate (DEHP), commonly referred to as di-octyl phthalate, is an important production chemical in the US. In addition to its major use as an additive in plastics, DEHP is widely used to evaluate the effectiveness of high efficiency particulate air (HEPA) filters. Historically, DEHP was also used in quantitative fit testing for respirators. Evaluations of this compound a decade ago showed that it can induce hepatocellular carcinomas in laboratory animals. Although most Department of Energy (DOE) facilities have since discontinued using DEHP in respirator fit testing, DEHP continues to be used for evaluating HEPA filters. This report summarizes available information on the toxicity, mutagenicity, carcinogenicity, and other hazards and problems posed by DEHP, specifically with reference to HEPA filter testing. Information on work practice improvements as well as the availability and suitability of DEHP substitutes are also presented. This material should assist the DOE in the safe use of this material.

In situ measurement of the efficiency of filtration installations in the nuclear industry by the soda-fluorescein (uranin) aerosol method: AFNOR standard NFX 44.011

International Nuclear Information System (INIS)

Dupoux, J.

1981-01-01

The in situ measurement of the efficiency of filtering installations in the French nuclear industry using the soda-fluorescein (uraniun) aerosol method is presented. A brief description and the interest of the method are discussed. Its use for the location of defects in filter elements and for in situ control of casing with tandem HEPA filter stages is described

Investigation of water accumulation in an offgas test facility HEPA housing

International Nuclear Information System (INIS)

Speed, D.L.; Burns, D.B.; Van Pelt, W.B.; Burns, H.H.

1997-01-01

The Consolidated Incineration Facility, at the Department of Energy's Savannah River Site, is designed to treat solid and liquid RCRA hazardous and mixed wastes generated by site operations and clean-up activities. During CIF's pretrial burn campaigns in 1995, an appreciable amount of water was recovered from the HEPA housings. Questions were immediately raised as to the source of the water, and the degree of wetness of the filters during operation. There are two primary issues involved: Water could reduce the life expectancy and performance of the HEPA filters, housing, and associated ducting, and wet HEPAs also present radiological concerns for personnel during filter change-out. A similar phenomenon was noted at the Offgas Components Test Facility (OCTF), a 1/10 scale pilot of CIF's air pollution control system. Tests at OCTF indicated the water's most likely origin to be vapor condensing out from the flue gas stream due to excessive air in-leakage at housing door seals, ducting flanges, and actual holes in the ducting. The rate of accumulation bears no statistical correlation to such process parameters as steam flow, reheater outlet temperature and offgas velocity in the duct. Test results also indicated that the HEPA filter media is moistened by the initial process flow while the facility is being brought on line. However, even when the HEPA filters were manually drenched prior to startup, they became completely dry within four hours of the time steam was introduced to the reheater. Finally, no demonstrable relationship was found between the degree of filter media wetness and filter dP

Stabilization void-fill encapsulation high-efficiency particulate filters

International Nuclear Information System (INIS)

Alexander, R.G.; Stewart, W.E.; Phillips, S.J.; Serkowski, M.M.; England, J.L.; Boynton, H.C.

1994-05-01

This report discusses high-efficiency particulate air (HEPA) filter systems that which are contaminated with radionuclides are part of the nuclear fuel processing systems conducted by the US Department of Energy (DOE) and require replacement and safe and efficient disposal for plant safety. Two K-3 HEPA filters were removed from service, placed burial boxes, buried, and safely and efficiently stabilized remotely which reduced radiation exposure to personnel and the environment

Investigation and deactivation of B Plant HEPA filters

International Nuclear Information System (INIS)

Roege, P.E.

1997-01-01

This paper describes the integrated approach used to manage environmental, safety, and health considerations related to the B Plant canyon exhaust air filters at the US Department of Energy (DOE) Hanford Site. The narrative illustrates the development and implementation of integrated safety management as applied to a facility and its systems undergoing deactivation. During their lifetime, the high efficiency particulate air (HEPA) filters prevented the release of significant quantities of radioactive materials into the air. As the material in B Plant AVESF accumulated on the filters, it created an unusual situation. Over long periods of time, the radiation dose from the filter loading, combined with aging and chemical exposure actually degrade those filters which were intended to protect against any release to the environment

Analysis of fire and smoke threat to off-gas HEPA filters in a transuranium processing plant

International Nuclear Information System (INIS)

Alvares, N.J.

1988-01-01

The author performed an analysis of fire risk to the high-efficiency particulate air (HEPA) filters that provide ventilation containment for a transuranium processing plant at the Oak Ridge National Laboratory. A fire-safety survey by an independent fire-protection consulting company had identified the HEPA filters in the facility's off-gas containment ventilation system as being at risk from fire effects. Independently studied were the ventilation networks and flow dynamics, and typical fuel loads were analyzed. It was found that virtually no condition for fire initiation exists and that, even if a fire started, its consequences would be minimal as a result of standard shut-down procedures. Moreover, the installed fire-protection system would limit any fire and thus would further reduce smoke or heat exposure to the ventilation components. 4 references, 4 figures, 5 tables

Review of Department of Energy HEPA filter test activities

International Nuclear Information System (INIS)

McIntyre, J.A.

1993-01-01

Filter Test Facilities (FTFs) and the FTF Technical Support Group (TSG) continue to provide services to the Department of Energy (DOE). Additional tasks relating to the HEPA filter cycle have been added to the TSG. The tasks include the quality assessment review for the in-place testing of HEPA filters at DOE sites and the formation of an in-place testing standards writing group. Summary of ongoing FTFs and TSG activities for FY 1990-FY 1992 including the technical input for implementation of the High Flow Alternative Test System (HFATS), update of the DOE Standards, the status of the quality assessment review and in-place testing standards writing group are discussed

HEPA filter fire (and subsequent unfiltered release)

International Nuclear Information System (INIS)

Powers, T.B.

1996-01-01

This document supports the development and presentation of the following accident scenario in the TWRS Final Safety Analysis Report: HEPA Filter Failure - Exposure to High Temperature or Pressure. The calculations needed to quantify the risk associated with this accident scenario are included within

Development of a double-layered ceramic filter for aerosol filtration at high-temperatures: the filter collection efficiency.

Science.gov (United States)

de Freitas, Normanda L; Gonçalves, José A S; Innocentini, Murilo D M; Coury, José R

2006-08-25

The performance of double-layered ceramic filters for aerosol filtration at high temperatures was evaluated in this work. The filtering structure was composed of two layers: a thin granular membrane deposited on a reticulate ceramic support of high porosity. The goal was to minimize the high pressure drop inherent of granular structures, without decreasing their high collection efficiency for small particles. The reticulate support was developed using the technique of ceramic replication of polyurethane foam substrates of 45 and 75 pores per inch (ppi). The filtering membrane was prepared by depositing a thin layer of granular alumina-clay paste on one face of the support. Filters had their permeability and fractional collection efficiency analyzed for filtration of an airborne suspension of phosphatic rock in temperatures ranging from ambient to 700 degrees C. Results revealed that collection efficiency decreased with gas temperature and was enhanced with filtration time. Also, the support layer influenced the collection efficiency: the 75 ppi support was more effective than the 45 ppi. Particle collection efficiency dropped considerably for particles below 2 microm in diameter. The maximum collection occurred for particle diameters of approximately 3 microm, and decreased again for diameters between 4 and 8 microm. Such trend was successfully represented by the proposed correlation, which is based on the classical mechanisms acting on particle collection. Inertial impaction seems to be the predominant collection mechanism, with particle bouncing/re-entrainment acting as detachment mechanisms.

Survey of HEPA filter applications and experience at Department of Energy sites

International Nuclear Information System (INIS)

Carbaugh, E.H.

1981-11-01

Results indicated that approximately 58% of the filters surveyed were changed out in the 1977 to 1979 study period and some 18% of all filters were changed out more than once. Most changeouts (60%) were due to the existence of a high pressure drop across the filter, indicative of filter plugging. The next most recurrent reasons for changeout and their percentage changeouts were leak test failure (15%) and preventive maintenance service life limit (12%). An average filter service life was calculated to be 3.0 years with a 2.0-year standard deviation. The labor required for filter changeout was calculated as 1.5 manhours per filter changed. Filter failures occurred with approximately 12% of all installed filters. Most failures (60%) occurred for unknown reasons and handling or installation damage accounted for an additional 20% of all failures. Media ruptures, filter frame failures and seal failures occurred with approximately equal frequency at 5 to 6% each. Subjective responses to the questionnaire indicate problems are: need for improved acid and moisture resistant filters; filters more readily disposable as radioactive waste; improved personnel training in filter handling and installation; and need for pretreatment of air prior to HEPA filtration

Measurement of filtration efficiency of Nuclepore filters challenged with polystyrene latex nanoparticles: experiments and modeling

International Nuclear Information System (INIS)

Ling, Tsz Yan; Wang Jing; Pui, David Y. H.

2011-01-01

Membrane filtration has been demonstrated to be effective for the removal of liquid-borne nanoparticles (NPs). Such technique can be applied to purify and disinfect drinking water as well as remove NPs in highly pure chemicals used in the industries. This study aims to study the filtration process of a model membrane filter, the Nuclepore filter. Experiments were carried out using standard filtration tools and the nanoparticle tracking analysis (NTA) technique was used to measure particle (50–500 nm) concentration upstream and downstream of the filter to determine the filtration efficiency. The NTA technique has been calibrated using 150-nm polystyrene latex particles to determine its accuracy of particle concentration measurement. Measurements were found reliable within a certain concentration limit (about 10 8 –10 10 particles/cm 3 ), which is dependent on the camera settings during the measurement. Experimental results are comparable with previously published data obtained using the aerosolization method, validating the capability of the NTA technique. The capillary tube model modified from that developed for aerosol filtration was found to be useful to represent the experimental results, when a sticking coefficient of 0.15 is incorporated. This suggests that only 15% of the particle collisions with the filter results in successful attachment. The small sticking coefficient found can be explained by the unfavorable surface interactions between the particles and the filter medium.

Transient Heating and Thermomechanical Stress Modeling of Ceramic HEPA Filters

Energy Technology Data Exchange (ETDEWEB)

Bogle, Brandon [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kelly, James [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Haslam, Jeffrey [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-09-29

The purpose of this report is to showcase an initial finite-element analysis model of a ceramic High-Efficiency Particulate (HEPA) Air filter design. Next generation HEPA filter assemblies are being developed at LLNL to withstand high-temperature fire scenarios by use of ceramics and advanced materials. The filters are meant for use in radiological and nuclear facilities, and are required to survive 500°C fires over an hour duration. During such conditions, however, collecting data under varying parameters can be challenging; therefore, a Finite Element Analysis model of the filter was conducted using COMSOL ® Multiphysics to analyze the effects of fire. Finite Element Analysis (FEA) modelling offers several opportunities: researchers can quickly and easily consider impacts of potential design changes, material selection, and flow characterization on filter performance. Specifically, this model provides stress references for the sealant at high temperatures. Modeling of full filter assemblies was deemed inefficient given the computational requirements, so a section of three tubes from the assembly was modeled. The model looked at the transient heating and thermomechanical stress development during a 500°C air flow at 6 CFM. Significant stresses were found at the ceramic-metal interfaces of the filter, and conservative temperature profiles at locations of interest were plotted. The model can be used for the development of sealants that minimize stresses at the ceramic-metal interface. Further work on the model would include the full filter assembly and consider heat losses to make more accurate predictions.

Overexpression of HepaCAM inhibits cell viability and motility through suppressing nucleus translocation of androgen receptor and ERK signaling in prostate cancer.

Science.gov (United States)

Song, Xuedong; Wang, Yin; Du, Hongfei; Fan, Yanru; Yang, Xue; Wang, Xiaorong; Wu, Xiaohou; Luo, Chunli

2014-07-01

HepaCAM is suppressed in a variety of human cancers, and involved in cell adhesion, growth, migration, invasion, and survival. However, the expression and function of HepaCAM in prostate cancer are still unknown. HepaCAM expression has been detected by RT-PCR, Western blotting and immunohistochemistry staining in prostate cell lines RWPE-1, LNCap, DU145, PC3, and in 75 human prostate tissue specimens, respectively. Meanwhile, the cell proliferation ability was detected by WST-8 assay. The role of HepaCAM in prostate cancer cell migration and invasion was examined by wound healing and transwell assay. And flow cytometry was used to observe the apoptosis of prostate cancer cells. Then we detected changes of Androgen Receptor translocation and ERK signaling using immunofluorescence staining and western blot after overexpression of HepaCAM. The HepaCAM expression was significantly down-regulated in prostate cancer tissues and undetected in prostate cancer cells. However, the low HepaCAM expression was not statistically associated with clinicopathological characteristics of prostate cancer. Overexpression of HepaCAM in prostate cancer cells decreased the cell proliferation, migration and invasion, and induced the cell apoptosis. Meanwhile, HepaCAM prevented the androgen receptor translocation from the cytoplasm to the nucleus and down-regulated the MAPK/ERK signaling. Our results suggested that HepaCAM acted as a tumor suppressor in prostate cancer. HepaCAM inhibited cell viability and motility which might be through suppressing the nuclear translocation of Androgen Receptor and down-regulating the ERK signaling. Therefore, it was indicated that HepaCAM may be a potential therapeutic target for prostate cancer. © 2014 Wiley Periodicals, Inc.

Feasibility for the medium efficiency filter as a postfilter in the air cleaning unit

International Nuclear Information System (INIS)

Lim, H. S.; Jung, D. Y.; Byun, S. C.; Kim, S. H.

2002-01-01

The Air Cleaning Unit (ACU) is provided in a nuclear facility to filter the radioactive materials in gaseous effluents released from the facility during normal operation and during a postulated accident. The Air Cleaning Unit (ACU) consists of pre-HEPA filters, charcoal adsorber, post HEPA filters, fans, etc. The charcoal filters keep on-site dose and off-site effluents ALARA, consistent with regulatory requirements. The function of HEPA filter downstream of charcoal(carbon) adsorber in ACU is to catch potential radioactive carbon dust and to be a backup in the event of failure of upstream HEPA. Previous Regulatory Guide use only post HEPA filter of charcoal adsorber downstream but the Regulatory Guide of current revisions allows use of 95% dust spot efficiency filters in lieu of HEPA at the downstream of the carbon adsorber. In this paper is described that the background information of filters, Current Regulatory Guide of revised by the United States Nuclear Regulatory Commission and the feasibility for the medium efficiency filter as a carbon adsorber post filter in the Air Cleaning Unit

Advantageous use of HepaRG cells for the screening and mechanistic study of drug-induced steatosis

Energy Technology Data Exchange (ETDEWEB)

Tolosa, Laia [Unidad de Hepatología Experimental, Instituto de Investigación Sanitaria La Fe, Valencia 46026 (Spain); Gómez-Lechón, M. José [Unidad de Hepatología Experimental, Instituto de Investigación Sanitaria La Fe, Valencia 46026 (Spain); CIBERehd, FIS, Barcelona 08036 (Spain); Jiménez, Nuria [Unidad de Hepatología Experimental, Instituto de Investigación Sanitaria La Fe, Valencia 46026 (Spain); Hervás, David [Biostatistics Unit, Instituto de Investigación Sanitaria La Fe, Valencia 46026 (Spain); Jover, Ramiro [Unidad de Hepatología Experimental, Instituto de Investigación Sanitaria La Fe, Valencia 46026 (Spain); CIBERehd, FIS, Barcelona 08036 (Spain); Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad de Valencia, Valencia 46010 (Spain); Donato, M. Teresa, E-mail: donato_mte@gva.es [Unidad de Hepatología Experimental, Instituto de Investigación Sanitaria La Fe, Valencia 46026 (Spain); CIBERehd, FIS, Barcelona 08036 (Spain); Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad de Valencia, Valencia 46010 (Spain)

2016-07-01

Only a few in vitro assays have been proposed to evaluate the steatotic potential of new drugs. The present study examines the utility of HepaRG cells as a cell-based assay system for screening drug-induced liver steatosis. A high-content screening assay was run to evaluate multiple toxicity-related cell parameters in HepaRG cells exposed to 28 compounds, including drugs reported to cause steatosis through different mechanisms and non-steatotic compounds. Lipid content was the most sensitive parameter for all the steatotic drugs, whereas no effects on lipid levels were produced by non-steatotic compounds. Apart from fat accumulation, increased ROS production and altered mitochondrial membrane potential were also found in the cells exposed to steatotic drugs, which indicates that all these cellular events contributed to drug-induced hepatotoxicity. These findings are of clinical relevance as most effects were observed at drug concentrations under 100-fold of the therapeutic peak plasmatic concentration. HepaRG cells showed increased lipid overaccumulation vs. HepG2 cells, which suggests greater sensitivity to drug-induced steatosis. An altered expression profile of transcription factors and the genes that code key proteins in lipid metabolism was also found in the cells exposed to drugs capable of inducing liver steatosis. Our results generally indicate the value of HepaRG cells for assessing the risk of liver damage associated with steatogenic compounds and for investigating the molecular mechanisms involved in drug-induced steatosis. - Highlights: • HepaRG cells were explored as an in vitro model to detect steatogenic potential. • Multiple toxicity-related endpoints were analysed by HCS. • HepaRG showed a greater sensitivity to drug-induced steatosis than HepG2 cells. • Changes in the expression of genes related to lipid metabolism were revealed. • HepaRG allow mechanistic understanding of liver damage induced by steatogenic drugs.

Advantageous use of HepaRG cells for the screening and mechanistic study of drug-induced steatosis

International Nuclear Information System (INIS)

Tolosa, Laia; Gómez-Lechón, M. José; Jiménez, Nuria; Hervás, David; Jover, Ramiro; Donato, M. Teresa

2016-01-01

Only a few in vitro assays have been proposed to evaluate the steatotic potential of new drugs. The present study examines the utility of HepaRG cells as a cell-based assay system for screening drug-induced liver steatosis. A high-content screening assay was run to evaluate multiple toxicity-related cell parameters in HepaRG cells exposed to 28 compounds, including drugs reported to cause steatosis through different mechanisms and non-steatotic compounds. Lipid content was the most sensitive parameter for all the steatotic drugs, whereas no effects on lipid levels were produced by non-steatotic compounds. Apart from fat accumulation, increased ROS production and altered mitochondrial membrane potential were also found in the cells exposed to steatotic drugs, which indicates that all these cellular events contributed to drug-induced hepatotoxicity. These findings are of clinical relevance as most effects were observed at drug concentrations under 100-fold of the therapeutic peak plasmatic concentration. HepaRG cells showed increased lipid overaccumulation vs. HepG2 cells, which suggests greater sensitivity to drug-induced steatosis. An altered expression profile of transcription factors and the genes that code key proteins in lipid metabolism was also found in the cells exposed to drugs capable of inducing liver steatosis. Our results generally indicate the value of HepaRG cells for assessing the risk of liver damage associated with steatogenic compounds and for investigating the molecular mechanisms involved in drug-induced steatosis. - Highlights: • HepaRG cells were explored as an in vitro model to detect steatogenic potential. • Multiple toxicity-related endpoints were analysed by HCS. • HepaRG showed a greater sensitivity to drug-induced steatosis than HepG2 cells. • Changes in the expression of genes related to lipid metabolism were revealed. • HepaRG allow mechanistic understanding of liver damage induced by steatogenic drugs.

Solutions for Dioctyl Phthalate (DOP) tested high efficiency particulate air (HEPA) filters destined for disposal at Hanford, Washington

International Nuclear Information System (INIS)

Gablin, K.A.

1992-11-01

In January 1992, Argonne National Laboratory East, Environmental and Waste Management Program, learned that a chemical material used for testing of all HEPA filters at the primary source, Flanders Filter, Inc. in Washington, NC, was considered a hazardous chemical by Washington State Dangerous Waste Regulations. These regulations are under the jurisdiction of the Washington Administration Code, Chapter 173-303, and therefore directly under impact the Hanford Site Solid Waste Acceptance Criteria. Dioctyl Phthalate, ''DOP'' as it is referred to in chemical abbreviation form, is added in small test quantities at the factory, at three Department of Energy (DOE) operated HEPA filter test facilities, and in the installed duct work at various operating laboratories or production facilities. When small amounts of radioactivity are added to the filter media in operation, the result is a mixed waste. This definition would normally only develop in the state of Washington since their acceptance criteria is ten times more stringent then the US Environmental Protection Agencys' (US EPA). Methods of Processing will be discussed, which will include detoxification, physical separation, heat and vacuum separation, and compaction. The economic impact of a mixed waste definition in the State of Washington, and an Low Level Waste (LLW) definition in other locations, may lend this product to be a prime candidate for commercial disposal in the future, or a possible de-listing by the State of Washington

Summary of meeting on disposal of LET ampersand D HEPA filters

International Nuclear Information System (INIS)

1991-01-01

This report is a compilation of correspondence between Westinghouse Idaho Nuclear Company and the US EPA over a period of time from 1988 to 1992 (most from 1991-92) regarding waste management compliance with EPA regulations. Typical subjects include: compliance with satellite accumulation requirements; usage of ''Sure Shot'' containers in place of aerosol cans; notice of upcoming recyclable battery shipments; disposition of batteries; HEPA filter leach sampling and permit impacts; functional and operation requirements for the spent filter handling system; summary of meeting on disposal of LET and D HEPA filters; solvent substitution database report; and mercury vapor light analytical testing

Fire protection considerations in the design of plutonium handling and storage facility

International Nuclear Information System (INIS)

Blanchard, A.

2000-01-01

Unwanted fire in a facility that handles plutonium must be addressed early in the facility design. Such fires have the potential for transporting radioactive contamination throughout the building and widespread downwind dispersal. Features that mitigate such events can be severely challenged during the fire. High temperatures can cause storage containers to burst; a very efficient dispersal mechanism for radioactive contamination. The fire will also establish ventilation patterns that cause the migration of smoke and radioactive contamination throughout the facility. The smoke and soot generated by the fire will enter the exhaust system and travel to the filtration system where it will deposit on the filters. The quantity of smoke generated during a typical multi-room fire is expected to blind most High Efficiency Particulate Airfilter (HEPA) media. The blinding can have two possible outcomes. (1) The air movement though the facility is reduced, compromising the negative pressure containment and allowing contamination to leave the building though doors and other openings; or (2) the filters collapse allowing the contamination to bypass the filtration media and exit the building through the filter plenum. HEPA filter blinding during severe fires can be prevented or mitigated. Increasing the face surface area of HEPA filters will increase the smoke filtration capacity of the system, thus preventing blinding. As an alternative sandfilters can be provided to mitigate the effects of the HEPA filter bypass. Both concepts have distinct advantages. This paper will explore these two design concepts and two others; it will describe the design requirements necessary for each concept to prevent unacceptable contamination spread. The intent is to allow the filter media selection to be based on a comprehensive understanding of the four different design concepts

A single standard for in-place testing of DOE HEPA filters - not

Energy Technology Data Exchange (ETDEWEB)

Mokler, B.V. [Los Alamos National Laboratory, NM (United States)

1995-02-01

This article is a review of arguments against the use of a single standard for in-place testing of DOE HEPA filters. The author feels that the term `standard` entails mandatory compliance. Additionally, the author feels that the variety of DOE HEPA systems requiring in-place testing is such that the guidance for testing must be written in a permissive fashion, allowing options and alternatives. With this in mind, it is not possible to write a single document entailing mandatory compliance for all DOE facilities.

Measurement of Biocolloid Collision Efficiencies for Granular Activated Carbon by Use of a Two-Layer Filtration Model

Science.gov (United States)

Paramonova, Ekaterina; Zerfoss, Erica L.; Logan, Bruce E.

2006-01-01

Point-of-use filters containing granular activated carbon (GAC) are an effective method for removing certain chemicals from water, but their ability to remove bacteria and viruses has been relatively untested. Collision efficiencies (α) were determined using clean-bed filtration theory for two bacteria (Raoutella terrigena 33257 and Escherichia coli 25922), a bacteriophage (MS2), and latex microspheres for four GAC samples. These GAC samples had particle size distributions that were bimodal, but only a single particle diameter can be used in the filtration equation. Therefore, consistent with previous reports, we used a particle diameter based on the smallest diameter of the particles (derived from the projected areas of 10% of the smallest particles). The bacterial collision efficiencies calculated using the filtration model were high (0.8 ≤ α ≤ 4.9), indicating that GAC was an effective capture material. Collision efficiencies greater than unity reflect an underestimation of the collision frequency, likely as a result of particle roughness and wide GAC size distributions. The collision efficiencies for microspheres (0.7 ≤ α ≤ 3.5) were similar to those obtained for bacteria, suggesting that the microspheres were a reasonable surrogate for the bacteria. The bacteriophage collision efficiencies ranged from ≥0.2 to ≤0.4. The predicted levels of removal for 1-cm-thick carbon beds ranged from 0.8 to 3 log for the bacteria and from 0.3 to 1.0 log for the phage. These tests demonstrated that GAC can be an effective material for removal of bacteria and phage and that GAC particle size is a more important factor than relative stickiness for effective particle removal. PMID:16885264

U-235 Holdup Measurements in the 321-M Lathe HEPA Banks

International Nuclear Information System (INIS)

Salaymeh, S.R.

2002-01-01

The Analytical Development Section of Savannah River Technology Center (SRTC) was requested by the Facilities Decommissioning Division (FDD) to determine the holdup of enriched uranium in the 321-M facility as part of an overall deactivation project of the facility. The results of the holdup assays are essential for determining compliance with the Waste Acceptance Criteria, Material Control and Accountability, and to meet criticality safety controls. This report covers holdup measurements of uranium residue in six high efficiency particulate air (HEPA) filter banks of the A-lathe and B-lathe exhaust systems of the 321-M facility. This report discusses the non-destructive assay measurements, assumptions, calculations, and results of the uranium holdup in these six items

Aerosol filtration

International Nuclear Information System (INIS)

First, M.W.; Gilbert, H.

1982-01-01

Significant developments in high-efficiency filtration for nuclear applications are reviewed for the period 1968 to 1980. Topics of special interest include (1) factory (bench) and in-place test methods, (2) new developments in paper and filter unit construction methods, (3) vented containment air cleaning systems for liquid-metal fast breeder reactors and light-water-moderated reactors, and (4) decontamination of off-gases from nuclear waste volume-reduction processes. Standards development has been vigorously pursued during this period, but advances in filtration theory have been few. One of the significant changes likely to occur in the immediate future is adoption of the European style of high-efficiency particulate air filters instead of those which have been in service for the past three decades to obtain the benefits of having almost twice as much filter paper in the same filter cartridge

Studies on Hepa filter test methods

International Nuclear Information System (INIS)

Lee, S.H.; Jon, K.S.; Park, W.J.; Ryoo, R.

1981-01-01

The purpose of this study is to compare testing methods of the HEPA filter adopted in other countries with each other, and to design and construct a test duct system to establish testing methods. The American D.O.P. test method, the British NaCl test method and several other independently developed methods are compared. It is considered that the D.O.P. method is most suitable for in-plant and leak tests

Test plan for N2 HEPA filters assembly shop stock used on PFP E4 exhaust system

International Nuclear Information System (INIS)

DICK, J.D.

1999-01-01

At Plutonium Finishing Plant (PFP) and Plutonium Reclamation Facility (PRF) Self-contained HEPA filters, encased in wooden frames and boxes, are installed in the E4 Exhaust Ventilation System to provide confinement of radioactive releases to the environment and confinement of radioactive contamination within designated zones inside the facility. Recently during the routine testing in-leakage was discovered downstream of the Self-contained HEPA filters boxes. This Test Plan describes the approach to conduct investigation of the root causes for the in-leakage of HEPA filters

Dynamic Heterogeneous Multiscale Filtration Model: Probing Micro- and Macroscopic Filtration Characteristics of Gasoline Particulate Filters.

Science.gov (United States)

Gong, Jian; Viswanathan, Sandeep; Rothamer, David A; Foster, David E; Rutland, Christopher J

2017-10-03

Motivated by high filtration efficiency (mass- and number-based) and low pressure drop requirements for gasoline particulate filters (GPFs), a previously developed heterogeneous multiscale filtration (HMF) model is extended to simulate dynamic filtration characteristics of GPFs. This dynamic HMF model is based on a probability density function (PDF) description of the pore size distribution and classical filtration theory. The microstructure of the porous substrate in a GPF is resolved and included in the model. Fundamental particulate filtration experiments were conducted using an exhaust filtration analysis (EFA) system for model validation. The particulate in the filtration experiments was sampled from a spark-ignition direct-injection (SIDI) gasoline engine. With the dynamic HMF model, evolution of the microscopic characteristics of the substrate (pore size distribution, porosity, permeability, and deposited particulate inside the porous substrate) during filtration can be probed. Also, predicted macroscopic filtration characteristics including particle number concentration and normalized pressure drop show good agreement with the experimental data. The resulting dynamic HMF model can be used to study the dynamic particulate filtration process in GPFs with distinct microstructures, serving as a powerful tool for GPF design and optimization.

Multiple HEPA filter test methods, July 1, 1974--March 31, 1975

International Nuclear Information System (INIS)

Schuster, B.G.; Osetek, D.J.

1975-08-01

A laboratory apparatus has been constructed for testing two HEPA filters in a series configuration. The apparatus consists of an instrumented wind tunnel in which the HEPA filters are mounted, and an auxiliary wind tunnel for obtaining diluted samples of the challenge aerosol upstream of the first filter. Measurements performed with a single particle aerosol spectrometer demonstrate the capability for measuring overall protection factors of greater than 2.5 x 10 8 . The decay of penetration as a function of time in individual HEPA filters indicates no preferential size discrimination in the range of 0.1 μm to 1.0 μm; nor is there a preferential size discrimination of penetration in this same range. A theoretical feasibility study has been performed on the use of an inhomogeneous electric field/induced aerosol electric dipole interaction for potential use as an air cleaning mechanism. Numerical evaluation of a coaxial cylinder geometry indicates that the method is feasible for collection of particles down to 0.1 μm under typical airflow velocity conditions. Small modifications in the geometry may be incorporated to create an instrument capable of measuring particle size. Geometries other than coaxial cylinders are also under investigation

ANALYSIS OF THE FILTRATION EFFICIENCY OF WHITE WINES USING DIFFERENT FILTER AIDS

Directory of Open Access Journals (Sweden)

Pietro Catania

2010-03-01

Full Text Available The global wine market, having recently entered into full crisis, is suffering some changes in its production and marketing. The reasons for these changes are mainly due to new trends in consumer demand for wine safety and quality standards at low cost. Social cellars, in order to be included in this new trend, should focus on the rationalization of the production techniques to reduce the costs and improve the quality of wine. In the case of winemaking for the production of a wine stored in a bag-in-box, filtration is a very important technique because it gives the finished product clearness and stability. The experimentation was based on the application of a low cost filtration technique on white wines in order to test the retention efficiency as a function of various filter aids used in the production of daily wines with an IGT (Typical Geographic Indication brand. The results show that wines obtained from the different tests had no changes in terms of colour and aromas, while remarkable differences were obtained with regards to turbidity.

A Method for Cobalt and Cesium Leaching from Glass Fiber in HEPA Filter

International Nuclear Information System (INIS)

Kim, Gye Nam; Lee, Suk Chol; Yang, Hee Chul; Yoon, In Ho; Choi, Wang Kyu; Moon, Jei Kwon

2011-01-01

A great amount of radioactive waste has been generated during the operation of nuclear facilities. Recently, the storage space of a radioactive waste storage facility in the Korea Atomic Energy Research Institute (KAERI) was almost saturated with many radioactive wastes. So, the present is a point of time that a volume reduction of the wastes in a radioactive waste storage facility needs. There are spent HEPA filter wastes of about 2,226 sets in the radioactive waste storage facility in KAERI. All these spent filter wastes have been stored in accordance with their original form without any treatment. Up to now a compression treatment of these spent HEPA filters has been carried out to repack the compressed spent HEPA filters into a 200 liter drum for their volume reduction. Frame and separator are contaminated with a low concentration of nuclide, while the glass fiber is contaminated with a high concentration of nuclide. So, for the disposal of the glass filter to the environment, the glass fiber should be leached to lower its radioactive concentration first and then must be stabilized by solidification and so on. Therefore, it is necessary to develop a leaching process of glass fiber in a HEPA filter. Leaching is a separation technology, which is often used to remove a metal or a nuclide from a solid mixture with the help of a liquid solvent

Summary of efficiency testing of standard and high-capacity high-efficiency particulate air filters subjected to simulated tornado depressurization and explosive shock waves

International Nuclear Information System (INIS)

Smith, P.R.; Gregory, W.S.

1985-04-01

Pressure transients in nuclear facility air cleaning systems can originate from natural phenomena such as tornadoes or from accident-induced explosive blast waves. This study was concerned with the effective efficiency of high-efficiency particulate air (HEPA) filters during pressure surges resulting from simulated tornado and explosion transients. The primary objective of the study was to examine filter efficiencies at pressure levels below the point of structural failure. Both standard and high-capacity 0.61-m by 0.61-m HEPA filters were evaluated, as were several 0.2-m by 0.2-m HEPA filters. For a particular manufacturer, the material release when subjected to tornado transients is the same (per unit area) for both the 0.2-m by 0.2-m and the 0.61-m by 0.61-m filters. For tornado transients, the material release was on the order of micrograms per square meter. When subjecting clean HEPA filters to simulated tornado transients with aerosol entrained in the pressure pulse, all filters tested showed a degradation of filter efficiency. For explosive transients, the material release from preloaded high-capacity filters was as much as 340 g. When preloaded high-capacity filters were subjected to shock waves approximately 50% of the structural limit level, 1 to 2 mg of particulate was released

Filter testing and development for prolonged transuranic service and waste reduction

International Nuclear Information System (INIS)

Geer, J.A.; Buttedahl, O.I.; Skaats, C.D.; Terada, K.; Woodard, R.W.

1977-02-01

The life of High Efficiency Particulate Air (HEPA) filters used in transuranic service is influenced greatly by the gaseous and particulate matter to which the filters are exposed. The most severe conditions encountered at Rocky Flats are at the ventilation systems serving the plutonium recovery operations in Bldg. 771. A project of filter testing and development for prolonged transuranic service and waste reduction was formally initiated at Rocky Flats on July 1, 1975. The project is directed toward improving filtration methods which will prolong the life of HEPA filter systems without sacrificing effectiveness. Another important aspect of the project is to reduce the volume of HEPA filter waste shipped from the plant for long-term storage. Progress to September 30, 1976, is reported

Problems of multiphase fluid filtration

CERN Document Server

Konovalov, AN

1994-01-01

This book deals with a spectrum of problems related to the mathematical modeling of multiphase filtration. Emphasis is placed on an inseparable triad: model - algorithm - computer code. An analysis of new and traditional filtration problems from the point of view of both their numerical implementation and the reproduction of one or another technological characteristics of the processes under consideration is given. The basic principles which underlie the construction of efficient numerical methods taking into account the filtration problems are discussed: non-evolutionary nature, degeneration,

Noble gas control room accident filtration system for severe accident conditions (N-CRAFT)

International Nuclear Information System (INIS)

Hill, Axel; Stiepani, Cristoph; Drechsler, Michael

2015-01-01

Severe accidents might cause the release of airborne radioactive substances to the environment of the NPP either due to containment leakages or due to intentional filtered containment venting. In the latter case aerosols and iodine are retained, however noble gases are not retainable by the FCVS or by conventional air filtration systems like HEPA filters and iodine absorbers. Radioactive noble gases nevertheless dominate the activity release depending on the venting procedure and the weather conditions. To prevent unacceptable contamination of the control room atmosphere by noble gases, AREVA GmbH has developed a noble gas control room accident filtration system (CRAFT) which can supply purified fresh air to the control room without time limitation. The retention process is based on dynamic adsorption of noble gases on activated carbon. The system consists of delay lines (carbon columns) which are operated by a continuous and simultaneous adsorption and desorption process. CRAFT allows minimization of the dose rate inside the control room and ensures low radiation exposure to the staff by maintaining the control room environment suitable for prolonged occupancy throughout the duration of the accident. CRAFT consists of a proven modular design either transportable or permanently installed. (author)

HEPA Filter Disposal Write-Up 10/19/16

Energy Technology Data Exchange (ETDEWEB)

Loll, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-10-20

Process knowledge (PK) collection on HEPA filters is handled via the same process as other waste streams at LLNL. The Field technician or Characterization point of contact creates an information gathering document (IGD) in the IGD database, with input provided from the generator, and submits it for electronic approval. This document is essentially a waste generation profile, detailing the physical, chemical as well as radiological characteristics, and hazards, of a waste stream. It will typically contain a general, but sometimes detailed, description of the work processes which generated the waste. It will contain PK as well as radiological and industrial hygiene analytical swipe results, and any other analytical or other supporting knowledge related to characterization. The IGD goes through an electronic approval process to formalize the characterization and to ensure the waste has an appropriate disposal path. The waste generator is responsible for providing initial process knowledge information, and approves the IGD before it routed to chemical and radiological waste characterization professionals. This is the standard characterization process for LLNL-generated HEPA Filters.

Investigation of HEPA filters subjected to tornado pressure pulses

International Nuclear Information System (INIS)

Gregory, W.S.; Horak, H.L.; Smith, P.R.; Ricketts, C.

1977-03-01

An experimental program is described that will determine the response of 0.6-x 0.6-m (24-x 24-in.) high-efficiency particulate air (HEPA) filters to tornado-induced pressure transients. A blow-down system will be used to impose pressure differentials across the filters. Progress in construction of this system is reported with a description of the component parts and their functions. The test facility is essentially complete with the exception of an air dryer system that has not yet been delivered. Initial structural testing will begin in March 1977. A description is given of the instrumentation needed to measure air pressure, velocity, turbulence, humidity and particulate concentration. This instrumentation includes pressure transducers, humidity equipment, laser Doppler velocimeters (LDV), signal processors and a data acquisition system. Operational theory of the LDV and its proposed use as a particle counting device are described

Extension of the maintenance cycle of HEPA filters by optimization of the technical characteristics of filters and their construction

International Nuclear Information System (INIS)

Bella, H.; Stiehl, H.H.; Sinhuber, D.

1977-01-01

The knowledge of the parameters of HEPA filters used at present in nuclear plants allows optimization of such filters with respect to flow rate, pressure drop and service life. The application of optimizing new types of HEPA filters of improved performance is reported. The calculated results were checked experimentally. The use of HEPA filters optimized with respect to dust capacity and service life, and the effects of this new type of filter on the reduction of operating and maintenance costs are discussed

Air filtration in HVAC systems

CERN Document Server

Ginestet, Alain; Tronville, Paolo; Hyttinen, Marko

2010-01-01

Air filtration Guidebook will help the designer and user to understand the background and criteria for air filtration, how to select air filters and avoid problems associated with hygienic and other conditions at operation of air filters. The selection of air filters is based on external conditions such as levels of existing pollutants, indoor air quality and energy efficiency requirements.

HEPA Filter Performance under Adverse Conditions

International Nuclear Information System (INIS)

Parsons, Michael; Hogancamp, Kristina; Alderman, Steven; Waggoner, Charles

2007-01-01

This study involved challenging nuclear grade high-efficiency particulate air (HEPA) filters under a variety of conditions that can arise in Department of Energy (DOE) applications such as: low or high RH, controlled and uncontrolled challenge, and filters with physically damaged media or seals (i.e., leaks). Reported findings correlate filter function as measured by traditional differential pressure techniques in comparison with simultaneous instrumental determination of up and down stream PM concentrations. Additionally, emission rates and failure signatures will be discussed for filters that have either failed or exceeded their usable lifetime. Significant findings from this effort include the use of thermocouples up and down stream of the filter housing to detect the presence of moisture. Also demonstrated in the moisture challenge series of tests is the effect of repeated wetting of the filter. This produces a phenomenon referred to as transient failure before the tensile strength of the media weakens to the point of physical failure. An evaluation of the effect of particle size distribution of the challenge aerosol on loading capacity of filters is also included. Results for soot and two size distributions of KCl are reported. Loading capacities for filters ranged from approximately 70 g of soot to nearly 900 g for the larger particle size distribution of KCl. (authors)

High Efficiency Particulate Air (HEPA) Filter Generation, Characterization, and Disposal Experiences at the Oak Ridge National Laboratory

International Nuclear Information System (INIS)

Coffey, D. E.

2002-01-01

High Efficiency Particulate Air filtration is an essential component of the containment and ventilation systems supporting the research and development activities at the Oak Ridge National Laboratory. High Efficiency Particulate Air filters range in size from 7.6cm (3 inch) by 10.2 cm (4 inch) cylindrical shape filters to filter array assemblies up to 2.1 m (7 feet) high by 1.5 m (5 feet) wide. Spent filters are grouped by contaminates trapped in the filter media and become one of the components in the respective waste stream. Waste minimization and pollution prevention efforts are applied for both radiological and non-radiological applications. Radiological applications include laboratory hoods, glove boxes, and hot cells. High Efficiency Particulate Air filters also are generated from intake or pre-filtering applications, decontamination activities, and asbestos abatement applications. The disposal avenues include sanitary/industrial waste, Resource Conservation and Recovery Act and Toxic Substance Control Act, regulated waste, solid low-level waste, contact handled transuranic, and remote handled transuranic waste. This paper discusses characterization and operational experiences associated with the disposal of the spent filters across multiple applications

Rotating Ceramic Water Filter Discs System for Water Filtration

Directory of Open Access Journals (Sweden)

Riyadh Z. Al Zubaidy

2017-04-01

Full Text Available This work aimed to design, construct and operate a new laboratory scale water filtration system. This system was used to examine the efficiency of two ceramic filter discs as a medium for water filtration. These filters were made from two different ceramic mixtures of local red clay, sawdust, and water. The filtration system was designed with two rotating interfered modules of these filters. Rotating these modules generates shear force between water and the surfaces of filter discs of the filtration modules that works to reduce thickness of layer of rejected materials on the filters surfaces. Each module consists of seven filtration units and each unit consists of two ceramic filter discs. The average measured hydraulic conductivity of the first module was 13.7mm/day and that for the second module was 50mm/day. Results showed that the water filtration system can be operated continuously with a constant flow rate and the filtration process was controlled by a skin thin layer of rejected materials. The ceramic water filters of both filtration modules have high removal efficiency of total suspended solids up to 100% and of turbidity up to 99.94%.

Review of Department of Energy HEPA filter test activities, FY 1990--FY 1992

International Nuclear Information System (INIS)

McIntyre, J.A.

1992-01-01

Filter Test Facilities (FTFs) and the FTF Technical Support Group (TSG) continue to provide services to the Department of Energy (DOE). Additional tasks relating to the HEPA filter cycle have been added to the TSG. The tasks include the quality assessment review for the in-place testing of HEPA filters at DOE sites and the formation of an in-place testing standards writing group. Summary of ongoing FTFs and TSG activities for FY 1990-FY 1992 including the technical input for implementation of the High Flow Alternative Test System (HFATS), update of the DOE Standards, the status of the quality assessment review and in-place testing standards writing group are discussed

HEPA filter testing - Department of Energy Office of Nuclear Energy Facilities

Energy Technology Data Exchange (ETDEWEB)

Sherwood, G.L. Jr. [Department of Energy, Washington, DC (United States)

1995-02-01

This paper provides the background of, and some results from, a review of HEPA filter testing during 1993 at selected Department of Energy (DOE) facilities. Recommendations for improvements in standards resulting from the review are also presented.

Development of acid-resistant HEPA filter components

International Nuclear Information System (INIS)

Terada, K.; Woodard, R.W.; Buttedahl, O.I.

1981-01-01

Laboratory and in-service tests of various HEPA filter media and separators were conducted to establish their relative resistances to HNO 3 -HF vapors. Filter medium of glass fiber with Nomex additive and aluminum separators with an epoxy-vinyl coating have performed quite well in the acid environment in the laboratory, and in prototype-filters placed in service in a plenum at Rocky Flats. Proprietary filters with new design and/or components were also tested in service with generally good results

Effect of elevated temperature on the mechanical strength of HEPA filters

International Nuclear Information System (INIS)

Elfawal, M.M.; Eladham, K.A.; Hammed, F.H.; Abdrabbo, M.F.

1993-01-01

The effect of elevated temperature on the mechanical strength of HEPA filters was studied in order to evaluate and improve their performance under high temperature conditions. As part of this study the mechanical strength of HEPA filter medium which is the limiting factor in terms of the filter strength was experimentally studied at elevated temperature up to 400 degree C, and thermal exposure times ranged from 2 min to 4 h. The failure pressures of HEPA filter units after long exposure to 250 degree C were also investigated. The test results show that the medium strength decreases with increase in temperature challenge and thermal exposure time due to burnout of the organic binder used to improve the strength and flexibility of the medium. The test results also show that the tensile strength of the conventional filter medium drops to about 40 % of the value at room temperature after exposure to 250 degree C for 6 h; therefore, the continuous exposure of the conventional filter medium to this temperature is critical. The average failure differential pressures of all commercial tested filters were found to lie between 9 and 18 kPa at ambient temperature and between 6 and 11 kPa after thermal challenge at 250 degree C for 100 h. It was found that swelling and capture of the ends of individual pleats has led to filter failure.3 fig., 2 tab

International Space Station (ISS) Bacterial Filter Elements (BFEs): Filter Efficiency and Pressure Testing of Returned Units

Science.gov (United States)

Green, Robert D.; Agui, Juan H.; Vijayakumar, R.

2017-01-01

The air revitalization system aboard the International Space Station (ISS) provides the vital function of maintaining a clean cabin environment for the crew and the hardware. This becomes a serious challenge in pressurized space compartments since no outside air ventilation is possible, and a larger particulate load is imposed on the filtration system due to lack of sedimentation due to the microgravity environment in Low Earth Orbit (LEO). The ISS Environmental Control and Life Support (ECLS) system architecture in the U.S. Segment uses a distributed particulate filtration approach consisting of traditional High-Efficiency Particulate Adsorption (HEPA) media filters deployed at multiple locations in each U.S. Segment module; these filters are referred to as Bacterial Filter Elements, or BFEs. These filters see a replacement interval, as part of maintenance, of 2-5 years dependent on location in the ISS. In this work, we present particulate removal efficiency, pressure drop, and leak test results for a sample set of 8 BFEs returned from the ISS after filter replacement. The results can potentially be utilized by the ISS Program to ascertain whether the present replacement interval can be maintained or extended to balance the on-ground filter inventory with extension of the lifetime of ISS beyond 2024. These results can also provide meaningful guidance for particulate filter designs under consideration for future deep space exploration missions.

Protection of the vehicle cab environment against bacteria, fungi and endotoxins in composting facilities.

Science.gov (United States)

Schlosser, O; Huyard, A; Rybacki, D; Do Quang, Z

2012-06-01

Microbial quality of air inside vehicle cabs is a major occupational health risk management issue in composting facilities. Large differences and discrepancies in protection factors between vehicles and between biological agents have been reported. This study aimed at estimating the mean protection efficiency of the vehicle cab environment against bioaerosols with higher precision. In-cab measurement results were also analysed to ascertain whether or not these protection systems reduce workers' exposure to tolerable levels. Five front-end loaders, one mobile mixer and two agricultural tractors pulling windrow turners were investigated. Four vehicles were fitted with a pressurisation and high efficiency particulate air (HEPA) filtration system. The four others were only equipped with pleated paper filter without pressurisation. Bacteria, fungi and endotoxins were measured in 72 pairs of air samples, simultaneously collected inside the cab and on the outside of the cab with a CIP 10-M sampler. A front-end loader, purchased a few weeks previously, fitted with a pressurisation and high efficiency particulate air (HEPA) filtration system, and with a clean cab, exhibited a mean protection efficiency of between 99.47% CI 95% [98.58-99.97%] and 99.91% [99.78-99.98%] depending on the biological agent. It is likely that the lower protection efficiency demonstrated in other vehicles was caused by penetration through the only moderately efficient filters, by the absence of pressurisation, by leakage in the filter-sealing system, and by re-suspension of particles which accumulated in dirty cabs. Mean protection efficiency in regards to bacteria and endotoxins ranged between 92.64% [81.87-97.89%] and 98.61% [97.41-99.38%], and between 92.68% [88.11-96.08%] and 98.43% [97.44-99.22%], respectively. The mean protection efficiency was the lowest when confronted with fungal spores, from 59.76% [4.19-90.75%] to 94.71% [91.07-97.37%]. The probability that in-cab exposure to fungi

Evaluation of the HEPA filter in-place test method in a corrosive off-gas environment

International Nuclear Information System (INIS)

Murphy, L.P.; Wong, M.A.; Girton, R.C.

1978-01-01

Experiments were performed to determine if the combined effects of temperature, humidity, and oxides of nitrogen (NO/sub x/) hinder the in-place testing of high-efficiency particulate air (HEPA) filters used for cleaning the off-gas from a nuclear waste solidification facility. The laboratory system that was designed to simulate the process off-gas contained two HEPA filters in series with sample ports before each filter and after the filter bank. The system also included a reaction bomb for partial conversion of NO to NO 2 . Instrumentation measured stream flow, humidity, NO/sub x/ concentration, and temperature. Comparison measurements of the DOP concentrations were made by a forward light-scattering photometer and a single particle intra-cavity laser particle spectrometer. Experimental conditions could be varied, but maximum system capabilities were 95% relative humidity, 90 0 C, and 10,000 ppM of NO/sub x/. A 2 3 factorial experimental design was used for the test program. This design determined the main effects of each factor plus the interactions of the factors in combination. The results indicated that water vapor and NO/sub x/ interfere with the conventional photometer measurements. Suggested modifications that include a unique sample dryer are described to correct the interferences. The laser particle spectrometer appears to be an acceptable instrument for measurements under adverse off-gas conditions

New filtration system for efficient recovery of waterborne Cryptosporidium oocysts and Giardia cysts

DEFF Research Database (Denmark)

Al-Sabi, Mohammad Nafi Solaiman; Gad, J. A.; Riber, Ulla

2015-01-01

-)cysts (1x10(2); 10 replicates) was successfully amplified using real-time PCR.ConclusionsThe use of a metallic filter, sonication and air backwash' were key factors for creating a highly efficient system for recovery of apparently undamaged protozoa.Significance and Impact of the StudyThis reagent......AimsTo develop a filtration unit for efficient recovery of waterborne Cryptosporidium oocysts and Giardia cysts ((oo-)cysts) in drinking water.Methods and ResultsThis unit utilizes a metallic filter and an ultrasound transducer for eluting (oo-)cysts, with a fixed retentate backwash volume; approx....... 400l. Changes in the viability was evaluated by seeding wild type (oo-)cysts (1x10(4)) followed by sonication for 5, 10, 20 or 40s (five replicates for each period). Flow cytometry analysis showed negligible increase in the mortality of (oo-)cysts exposed to 5-10s of sonication. Recovery rate...

Preliminary studies to determine the shelf life of HEPA filters

Energy Technology Data Exchange (ETDEWEB)

Gilbert, H.; Fretthold, J.K.; Rainer, F. [Lawrence Livermore National Laboratory, CA (United States)] [and others

1995-02-01

We have completed a preliminary study using filter media tests and filter qualification tests to investigate the effect of shelf-life on HEPA filter performance. Our media studies showed that the tensile strength decreased with age, but the data were not sufficient to establish a shelf-life. Thermogravimetric analyses demonstrated that one manufacturer had media with low tensile strength due to insufficient binder. The filter qualification tests (heated air and overpressure) conducted on different aged filters showed that filter age is not the primary factor affecting filter performance; materials and the construction design have a greater effect. An unexpected finding of our study was that sub-standard HEPA filters have been installed in DOE facilities despite existing regulations and filter qualification tests. We found that the filter with low tensile strength failed the overpressure test. The same filter had passed the heated air test, but left the filter so structurally weak, it was prone to blow-out. We recommend that DOE initiate a filter qualification program to prevent this occurrence.

Comparison of high efficiency particulate filter testing methods

International Nuclear Information System (INIS)

1985-01-01

High Efficiency Particulate Air (HEPA) filters are used for the removal of submicron size particulates from air streams. In nuclear industry they are used as an important engineering safeguard to prevent the release of air borne radioactive particulates to the environment. HEPA filters used in the nuclear industry should therefore be manufactured and operated under strict quality control. There are three levels of testing HEPA filters: i) testing of the filter media; ii) testing of the assembled filter including filter media and filter housing; and iii) on site testing of the complete filter installation before putting into operation and later for the purpose of periodic control. A co-ordinated research programme on particulate filter testing methods was taken up by the Agency and contracts were awarded to the Member Countries, Belgium, German Democratic Republic, India and Hungary. The investigations carried out by the participants of the present co-ordinated research programme include the results of the nowadays most frequently used HEPA filter testing methods both for filter medium test, rig test and in-situ test purposes. Most of the experiments were carried out at ambient temperature and humidity, but indications were given to extend the investigations to elevated temperature and humidity in the future for the purpose of testing the performance of HEPA filter under severe conditions. A major conclusion of the co-ordinated research programme was that it was not possible to recommend one method as a reference method for in situ testing of high efficiency particulate air filters. Most of the present conventional methods are adequate for current requirements. The reasons why no method is to be recommended were multiple, ranging from economical aspects, through incompatibility of materials to national regulations

Recleaning of HEPA filters by reverse flow - evaluation of the underlying processes and the cleaning technique

International Nuclear Information System (INIS)

Leibold, H.; Leiber, T.; Doeffert, I.; Wilhelm, J.G.

1993-08-01

HEPA filter operation at high concentrations of fine dusts requires the periodic recleaning of the filter units in their service locations. Due to the low mechanical stress induced during the recleaning process the regenration via low pressure reverse flow is a very suitable technique. Recleanability of HEPA filter had been attained for particle diameter >0,4 μm at air velocities up to 1 m/s, but filter clogging occurred in case of smaller particles. The recleaning forces are too weak for particles [de

The effect of media area on the dust holding capacity of deep pleat HEPA filters

International Nuclear Information System (INIS)

Dyment, J.; Loughborough, D.

1997-01-01

The high potential cost of storage, treatment and disposal of radioactive wastes places a premium on the longevity of installed HEPA filters in situations in radioactive processing facilities where dust capacity is a life determining factor. Previous work investigated the dust holding capacity v pressure drop characteristics of different designs of HEPA filter and also the effect of using graded density papers. This paper records an investigation of the effect of media area variation on the dust holding capacity of the open-quotes deep-pleatclose quotes design of HEPA filter. As in the previously reported work two test dusts (carbon black and sub micron sodium chloride) in the range (0.15 - 0.4μm) were used. Media area adjustment was effected by varying the number of separators within the range 60 - 90. Results with the coarser dust allowed an optimum media area to be identified. Media areas greater or smaller than this optimum retained less dust than the optimum for the same terminal pressure drop. Conversely with the finer sodium chloride aerosol the dust holding capacity continued to increase up to the maximum area investigated. 7 refs., 4 figs

The effect of media area on the dust holding capacity of deep pleat HEPA filters

Energy Technology Data Exchange (ETDEWEB)

Dyment, J. [AWE, Aldermaston (United Kingdom); Loughborough, D. [AEAT Harwell, Oxford (United Kingdom)

1997-08-01

The high potential cost of storage, treatment and disposal of radioactive wastes places a premium on the longevity of installed HEPA filters in situations in radioactive processing facilities where dust capacity is a life determining factor. Previous work investigated the dust holding capacity v pressure drop characteristics of different designs of HEPA filter and also the effect of using graded density papers. This paper records an investigation of the effect of media area variation on the dust holding capacity of the {open_quotes}deep-pleat{close_quotes} design of HEPA filter. As in the previously reported work two test dusts (carbon black and sub micron sodium chloride) in the range (0.15 - 0.4{mu}m) were used. Media area adjustment was effected by varying the number of separators within the range 60 - 90. Results with the coarser dust allowed an optimum media area to be identified. Media areas greater or smaller than this optimum retained less dust than the optimum for the same terminal pressure drop. Conversely with the finer sodium chloride aerosol the dust holding capacity continued to increase up to the maximum area investigated. 7 refs., 4 figs.

Three-dimensional HepaRG model as an attractive tool for toxicity testing.

Science.gov (United States)

Leite, Sofia B; Wilk-Zasadna, Iwona; Zaldivar, Jose M; Airola, Elodie; Reis-Fernandes, Marcos A; Mennecozzi, Milena; Guguen-Guillouzo, Christiane; Chesne, Christopher; Guillou, Claude; Alves, Paula M; Coecke, Sandra

2012-11-01

The culture of HepaRG cells as three dimensional (3D) structures in the spinner-bioreactor may represent added value as a hepatic system for toxicological purposes. The use of a cost-effective commercially available bioreactor, which is compatible with high-throughput cell analysis, constitutes an attractive approach for routine use in the drug testing industry. In order to assess specific aspects of the biotransformation capacity of the bioreactor-based HepaRG system, the induction of CYP450 enzymes (i.e., CYP1A2, 2B6, 2C9, and 3A4) and the activity of the phase II enzyme, uridine diphosphate glucuronoltransferase (UGT), were tested. The long-term functionality of the system was demonstrated by 7-week stable profiles of albumin secretion, CYP3A4 induction, and UGT activities. Immunofluorescence-based staining showed formation of tissue-like arrangements including bile canaliculi-like structures and polar distribution of transporters. The use of in silico models to analyze the in vitro data related to hepatotoxic activity of acetaminophen (APAP) demonstrated the advantage of the integration of kinetic and dynamic aspects for a better understanding of the in vitro cell behavior. The bioactivation of APAP and its related cytotoxicity was assessed in a system compatible to high-throughput screening. The approach also proved to be a good strategy to reduce the time necessary to obtain fully differentiated cell cultures. In conclusion, HepaRG cells cultured in 3D spinner-bioreactors are an attractive tool for toxicological studies, showing a liver-like performance and demonstrating a practical applicability for toxicodynamic approaches.

Evaluation of the effect of media velocity on filter efficiency and most penetrating particle size of nuclear grade high-efficiency particulate air filters.

Science.gov (United States)

Alderman, Steven L; Parsons, Michael S; Hogancamp, Kristina U; Waggoner, Charles A

2008-11-01

High-efficiency particulate air (HEPA) filters are widely used to control particulate matter emissions from processes that involve management or treatment of radioactive materials. Section FC of the American Society of Mechanical Engineers AG-1 Code on Nuclear Air and Gas Treatment currently restricts media velocity to a maximum of 2.5 cm/sec in any application where this standard is invoked. There is some desire to eliminate or increase this media velocity limit. A concern is that increasing media velocity will result in higher emissions of ultrafine particles; thus, it is unlikely that higher media velocities will be allowed without data to demonstrate the effect of media velocity on removal of ultrafine particles. In this study, the performance of nuclear grade HEPA filters, with respect to filter efficiency and most penetrating particle size, was evaluated as a function of media velocity. Deep-pleat nuclear grade HEPA filters (31 cm x 31 cm x 29 cm) were evaluated at media velocities ranging from 2.0 to 4.5 cm/sec using a potassium chloride aerosol challenge having a particle size distribution centered near the HEPA filter most penetrating particle size. Filters were challenged under two distinct mass loading rate regimes through the use of or exclusion of a 3 microm aerodynamic diameter cut point cyclone. Filter efficiency and most penetrating particle size measurements were made throughout the duration of filter testing. Filter efficiency measured at the onset of aerosol challenge was noted to decrease with increasing media velocity, with values ranging from 99.999 to 99.977%. The filter most penetrating particle size recorded at the onset of testing was noted to decrease slightly as media velocity was increased and was typically in the range of 110-130 nm. Although additional testing is needed, these findings indicate that filters operating at media velocities up to 4.5 cm/sec will meet or exceed current filter efficiency requirements. Additionally

Penetration of HEPA filters by alpha recoil aerosols

International Nuclear Information System (INIS)

McDowell, W.J.; Seeley, F.G.; Ryan, M.T.

1976-01-01

Tests at Oak Ridge National Laboratory confirmed that alpha-emitting particulate matter does penetrate high-efficiency filter medium, identical to that used in HEPA filters, much more effectively than do non-radioactive or beta-gamma active aerosols. Filter retention efficiencies drastically lower than the 99.97 percent quoted for ordinary particulate matter have been observed with 212 Pb, 253 Es, and 238 Pu sources, indicating that the phenomenon is common to all of these and probably to all alpha-emitting materials of appropriate half-life. Results with controlled air-flow through filters in series are consistent with the picture of small particles dislodged from the ''massive'' surface of an alpha-active material, and then repeatedly dislodged from positions on the filter fibers, by the alpha recoils. The process shows only a small dependence on the physical form of the source material. Oxide dust, nitrate salt, and plated metal all seem to generate the recoil particles effectively. The amount penetrating a series of filters depends on the total amount of activity in the source material, its specific activity, and the length of time of air flow. Dependence on the air flow velocity is slight. It appears that this phenomenon has not been observed in previous experiments with alpha-active aerosols because the tests did not continue for a sufficiently long time. A theoretical model of the process has been developed, amenable to computer handling, that should allow calculation of the rate constants associated with the transfer through and release of radioactive material from a filter system by this process

Development of a low-cost biogas filtration system to achieve higher-power efficient AC generator

Science.gov (United States)

Mojica, Edison E.; Ardaniel, Ar-Ar S.; Leguid, Jeanlou G.; Loyola, Andrea T.

2018-02-01

The paper focuses on the development of a low-cost biogas filtration system for alternating current generator to achieve higher efficiency in terms of power production. A raw biogas energy comprises of 57% combustible element and 43% non-combustible elements containing carbon dioxide (36%), water vapor (5%), hydrogen sulfide (0.5%), nitrogen (1%), oxygen (0 - 2%), and ammonia (0 - 1%). The filtration system composes of six stages: stage 1 is the water scrubber filter intended to remove the carbon dioxide and traces of hydrogen sulfide; stage 2 is the silica gel filter intended to reduce the water vapor; stage 3 is the iron sponge filter intended to remove the remaining hydrogen sulfide; stage 4 is the sodium hydroxide solution filter intended to remove the elemental sulfur formed during the interaction of the hydrogen sulfide and the iron sponge and for further removal of carbon dioxide; stage 5 is the silica gel filter intended to further eliminate the water vapor gained in stage 4; and, stage 6 is the activated carbon filter intended to remove the carbon dioxide. The filtration system was able to lower the non-combustible elements by 72% and thus, increasing the combustible element by 54.38%. The unfiltered biogas is capable of generating 16.3 kW while the filtered biogas is capable of generating 18.6 kW. The increased in methane concentration resulted to 14.11% increase in the power output. The outcome resulted to better engine performance in the generation of electricity.

Institute for Clean Energy Technology Mississippi State University NSR&D Aged HEPA Filter Study Final Report

Energy Technology Data Exchange (ETDEWEB)

Jacks, Robert [Mississippi State Univ., Mississippi State, MS (United States); Stormo, Julie [Mississippi State Univ., Mississippi State, MS (United States); Rose, Coralie [Mississippi State Univ., Mississippi State, MS (United States); Rickert, Jaime [Mississippi State Univ., Mississippi State, MS (United States); Waggoner, Charles A. [Mississippi State Univ., Mississippi State, MS (United States)

2017-03-22

Data have demonstrated that filter media lose tensile strength and the ability to resist the effects of moisture as a function of age. Testing of new and aged filters needs to be conducted to correlate reduction of physical strength of HEPA media to the ability of filters to withstand upset conditions. Appendix C of the Nuclear Air Cleaning Handbook provides the basis for DOE’s HEPA filter service life guidance. However, this appendix also points out the variability of data, and it does not correlate performance of aged filters to degradation of media due to age. Funding awarded by NSR&D to initiate full-scale testing of aged HEPA filters addresses the issue of correlating media degradation due to age with testing of new and aged HEPA filters under a generic design basis event set of conditions. This funding has accelerated the process of describing this study via: (1) establishment of a Technical Working Group of all stakeholders, (2) development and approval of a test plan, (3) development of testing and autopsy procedures, (4) acquiring an initial set of aged filters, (5) testing the initial set of aged filters, and (6) developing the filter test report content for each filter tested. This funding was very timely and has moved the project forward by at least three years. Activities have been correlated with testing conducted under DOE-EM funding for evaluating performance envelopes for AG-1 Section FC Separator and Separatorless filters. This coordination allows correlation of results from the NSR&D Aged Filter Study with results from testing new filters of the Separator and Separatorless Filter Study. DOE-EM efforts have identified approximately 100 more filters of various ages that have been stored under Level B conditions. NSR&D funded work allows a time for rigorous review among subject matter experts before moving forward with development of the testing matrix that will be used for additional filters. The NSR&D data sets are extremely valuable in as much

High efficiency steel filters for nuclear air cleaning

International Nuclear Information System (INIS)

Bergman, W.; Conner, J.; Larsen, G.; Lopez, R.; Turner, C.; Vahla, G.; Violet, C.; Williams, K.

1991-01-01

The authors have, in cooperation with industry, developed high-efficiency filters made from sintered stainless-steel fibers for use in several air-cleaning applications in the nuclear industry. These filters were developed to overcome the failure modes in present high-efficiently particulate air (HEPA) filters. HEPA filters are made from glass paper and glue, and they may fail when they get hot or wet and when they are overpressured. In developing steel filters, they first evaluated the commercially available stainless-steel filter media made from sintered powder and sintered fiber. The sintered-fiber media performed much better than sintered-powder media, and the best media had the smallest fiber diameter. Using the best media, prototype filters were then built for venting compressed gases and evaluated in their automated filter tester

Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems

OpenAIRE

Ng, Bing Feng; Xiong, Jin Wen; Wan, Man Pun

2017-01-01

The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle cl...

Filtration of Nanoparticles: Evolution of Cake Structure and Pressure-Drop

DEFF Research Database (Denmark)

Elmøe, Tobias Dokkedal; Tricoli, Antonio; Grunwaldt, Jan-Dierk

2009-01-01

The detailed three-dimensional accumulation of deposits and the build-up of pressuredrop during filtration of compressible gases laden with nanoparticles (diameter dp=50 nm) through capillaries (1–4 micron radius) was investigated by Langevin dynamics (LD) at Peclet number, Pe, 0.01–10. At low Pe...... with constant solid volume fraction began to form, accompanied with build-up of pressuredrop which was in excellent agreement with classic cake filtration theory. An expression for the solid volume fraction of the cake (fsd,c) was obtained as a sole function of Pe. In addition, the filtration efficiency became...... 1 after clogging, since the cake acts as a perfectly efficient filter. Penetration of nanoparticles takes place until the onset of cake filtration at high Pe (1–10) while for smaller ones (0.01–0.1) it is negligible at the employed capillary radii and length (10 micron). Analytical expressions...

Cross-flow filtration and axial filtration

International Nuclear Information System (INIS)

Kraus, K.A.

1974-01-01

Two relatively novel alternative solid-liquid-separation techniques of filtration are discussed. In cross-flow filtration, the feed is pumped past the filtering surface. While in axial filtration the filter, mounted on a rotor, is moved with respect to the feed. While large-scale application of the axial filter is still in doubt, it permits with little expenditure of time and money, duplication of many hydrodynamic aspects of cross-flow filtration for fine-particle handling problems. The technique has been applied to municipal wastes, low-level radioactive waste treatment plant, lead removal from industrial wastes, removal of pulp-mill contaminants, textile-mill wastes, and pretreatment of saline waters by lime-soda process in preparation for hyperfiltration. Economics and energy requirements are also discussed

Filtration aids in uranium ore processing

International Nuclear Information System (INIS)

Ford, H.L.; Levine, N.M.; Risdon, A.L.

1975-01-01

The patent describes a process whereby improved flocculation efficiency and filtration of carbonate leached uranium ore pulps are obtained by treating the filter feed slurry with an aqueous solution of hydroxyalkyl guar. (J.R.)

The high efficiency steel filters for nuclear air cleaning

International Nuclear Information System (INIS)

Bergman, W.; Larsen, G.; Lopez, R.; Williams, K.; Violet, C.

1990-08-01

We have, in cooperation with industry, developed high-efficiency filters made from sintered stainless-steel fibers for use in several air-cleaning applications in the nuclear industry. These filters were developed to overcome the failure modes in present high-efficiency particulate air (HEPA) filters. HEPA filters are made from glass paper and glue, and they may fail when they get hot or wet and when they are overpressured. In developing our steel filters, we first evaluated the commercially available stainless-steel filter media made from sintered powder and sintered fiber. The sintered-fiber media performed much better than sintered-powder media, and the best media had the smallest fiber diameter. Using the best media, we then built prototype filters for venting compressed gases and evaluated them in our automated filter tester. 12 refs., 20 figs

Evaluation of the ICET Test Stand to Assess the Performance of a Range of Ceramic Media Filter Elements in Support of ASME AG-1 Subsection FO

Energy Technology Data Exchange (ETDEWEB)

Schemmel, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-04-26

High Efficiency Particulate Air (HEPA) filters are defined as extended-medium, dry-type filters with: (1) a minimum particle removal efficiency of no less than 99.97 percent for 0.3 micrometer particles, (2) a maximum, clean resistance of 1.0 inch water column (in. WC) when operated at 1,000 cubic feet per minute (CFM), and (3) a rigid casing that extends the full depth of the medium. Specifically, ceramic media HEPA filters provide better performance at elevated temperatures, are moisture resistant and nonflammable, can perform their function if wetted and exposed to greater pressures, and can be cleaned and reused. This paper describes the modification and design of a large scale test stand which properly evaluates the filtration characteristics of a range of ceramic media filters challenged with a nuclear aerosol agent in order to develop Section FO of ASME AG-1.

HEPA-filter smoke plugging problem

International Nuclear Information System (INIS)

Gaskill, J.R.; Magee, M.W.

1975-01-01

Actual experiences indicate that during the early stages of a fire, pyrolysis and incomplete combustion of organic materials used in the furnishings or interior finishes of laboratories yield copious quantities of smoke particulates, both liquid and solid. Furthermore, the use of fire retardants in materials used for the above purpose interferes with the combustion process, so that burning of such materials in later stages of a fire will yield dense smoke. These particulates can plug up a HEPA filter or even a more porous prefilter, and thus effectively shut off the exhaust ventilation. In this case, the fire room will pressurize and contamination may spread in an uncontrolled manner. Both small- and large-scale tests have been conducted to evaluate the nature and degree of the problem as a function of materials involved, rate of exposure to the fire, and kinds and temperatures of smoke so generated. Some test work has also been done on scrubbing of smoke. Proposed future work is described. (U.S.)

Ultrasound efficiency in relation to sodium hypochlorite and filtration adsorption in microbial elimination in a water treatment plant

Directory of Open Access Journals (Sweden)

Antonio Roberto Crystal Bello

2005-09-01

Full Text Available Processes like ultrasound, chlorination and filtration-adsorption were compared to eliminate microorganisms and to adjust established parameters of public drinking water. A mini water treatment plant (WTP-CB, in pilot scale, was projected and built to evaluate each process influence as: decontamination, coagulation-flocculation, sedimentation and filtration. Total and fecal coliforms, Escherichia coli and heterotrophic bacteria and physic/chemical parameters were quantified from water. Ultrasound, chlorination and filtration-adsorption were efficient to inactivate and/or eliminate bacteria. Ultrasound decontamination in addition to coagulation-flocculation, sedimentation and filtration, could be considered as an alternative treatment water solution where prechlorination, coagulation-flocculation, sedimentation and filtration were used. The chlorination itself was efficient in inactivating bacteria despite of the coagulation-flocculation process; however, in the absence of the coagulation process, the resultant water did not achieve the established parameters. The filtration-adsorption was an important process to eliminate bacteria, showing that the filter retained particles, suspended solids, besides chemical substances and microorganisms.Comparou-se diferentes processos: ultra-som, cloração e filtração/adsorção para eliminação de microrganismos e adequação de outros parâmetros exigidos para água de abastecimento público. Para avaliar a influência de cada processo: desinfecção, coagulação/floculação, decantação e filtração foi projetada e construída uma Estação de Tratamento de Água (ETA-CB em escala piloto. Foram avaliados coliformes, bactérias heterotróficas e parâmetros físico/químicos. Ondas ultra-sônicas, cloração e filtração/adsorção mostraram-se eficientes na inativação e/ou eliminação de bactérias. O processo de desinfecção com ultra-som juntamente com a coagulação/floculação, decanta

Characterizing radionuclides in the B Plant HEPA filters

International Nuclear Information System (INIS)

Roege, P.E.

1998-01-01

B Plant was built during World War II to separate plutonium for nuclear weapons from reactor fuel. Later, the plant was re-equipped and used to separate radioactive fission products from the Hanford Site's nuclear processing waste tanks. The facility is now being deactivated: eliminating, stabilizing, and documenting existing hazards to allow safe surveillance and maintenance pending a final disposition which is yet to be determined. The processing areas of the plant, including process cells and exhaust air system, are heavily contaminated with radioactive cesium and strontium from the tank waste separation process. However, detailed characterization is difficult because many of these areas are inaccessible because of physical barriers and high radiological dose rates. The five existing canyon high efficiency particulate air (HEPA) filters were thought to contain a significant fraction of the inventory, but estimates were highly uncertain. This paper describes the process used to inspect and characterize the radionuclide content in one of these filters. The investigation required a collaborative effort among field and technical personnel. Sophisticated computer modeling and detector technologies were employed in conjunction with sound radiological control and field work practices. The outcome of the effort was a considerable reduction in the filter inventory estimate, accompanied by a greatly improved level of confidence in the data. The information derived from this project will provide a sound basis for future decisions regarding filter disposition

Plutonium Finishing Plant (PFP) Waste Composition and High Efficiency Particulate Air Filter Loading

Energy Technology Data Exchange (ETDEWEB)

ZIMMERMAN, B.D.

2000-12-11

This analysis evaluates the effect of the Plutonium Finishing Plant (PFP) waste isotopic composition on Tank Farms Final Safety Analysis Report (FSAR) accidents involving high-efficiency particulate air (HEPA) filter failure in Double-Contained Receiver Tanks (DCRTs). The HEPA Filter Failure--Exposure to High Temperature or Pressure, and Steam Intrusion From Interfacing Systems accidents are considered. The analysis concludes that dose consequences based on the PFP waste isotopic composition are bounded by previous FSAR analyses. This supports USQD TF-00-0768.

Proposed retrofit of HEPA filter plenums with injection and sampling manifolds for in-place filter testing

Energy Technology Data Exchange (ETDEWEB)

Fretthold, J.K. [EG& G Rocky Flats, Inc., Golden, CO (United States)

1995-02-01

The importance of testing HEPA filter exhaust plenums with consideration for As Low as Reasonably Achievable (ALARA) will require that new technology be applied to existing plenum designs. HEPA filter testing at Rocky Flats has evolved slowly due to a number of reasons. The first plenums were built in the 1950`s, preceding many standards. The plenums were large, which caused air dispersal problems. The systems were variable air flow. Access to the filters was difficult. The test methods became extremely conservative. Changes in methods were difficult to make. The acceptance of new test methods has been made in recent years with the change in plant mission and the emphasis on worker safety.

Submicron and Nanoparticulate Matter Removal by HEPA-Rated Media Filters and Packed Beds of Granular Materials

Science.gov (United States)

Perry, J. L.; Agui, J. H.; Vijayakimar, R

2016-01-01

Contaminants generated aboard crewed spacecraft by diverse sources consist of both gaseous chemical contaminants and particulate matter. Both HEPA media filters and packed beds of granular material, such as activated carbon, which are both commonly employed for cabin atmosphere purification purposes have efficacy for removing nanoparticulate contaminants from the cabin atmosphere. The phenomena associated with particulate matter removal by HEPA media filters and packed beds of granular material are reviewed relative to their efficacy for removing fine (less than 2.5 micrometers) and ultrafine (less than 0.01 micrometers) sized particulate matter. Considerations are discussed for using these methods in an appropriate configuration to provide the most effective performance for a broad range of particle sizes including nanoparticulates.

Impact of humidification and nebulization during expiratory limb protection: an experimental bench study.

Science.gov (United States)

Tonnelier, Alexandre; Lellouche, François; Bouchard, Pierre Alexandre; L'Her, Erwan

2013-08-01

Different filtering devices are used during mechanical ventilation to avoid dysfunction of flow and pressure transducers or for airborne microorganisms containment. Water condensates, resulting from the use of humidifiers, but also residual nebulization particles may have a major influence on expiratory limb resistance. To evaluate the influence of nebulization and active humidification on the resistance of expiratory filters. A respiratory system analog was constructed using a test lung, an ICU ventilator, heated humidifiers, and a piezoelectric nebulizer. Humidifiers were connected to different types of circuits (unheated, mono-heated, new-generation and old-generation bi-heated). Five filter types were evaluated: electrostatic, heat-and-moisture exchanger, standard, specific, and internal heated high-efficiency particulate air [HEPA] filter. Baseline characteristics were obtained from each dry filter. Differential pressure measurements were carried out after 24 hours of continuous in vitro use for each condition, and after 24 hours of use with an old-generation bi-heated circuit without nebulization. While using unheated circuits, measurements had to be interrupted before 24 hours for all the filtering devices except the internal heated HEPA filter. The heat-and-moisture exchangers occluded before 24 hours with the unheated and mono-heated circuits. The circuit type, nebulization practice, and duration of use did not influence the internal heated HEPA filter resistance. Expiratory limb filtration is likely to induce several major adverse events. Expiratory filter resistance increase is due mainly to the humidification circuit type, rather than to nebulization. If filtration is mandatory while using an unheated circuit, a dedicated filter should be used for ≤ 24 hours, or a heated HEPA for a longer duration.

Preliminary studies to determine the shelf life of HEPA filters. Revision 1

International Nuclear Information System (INIS)

Gilbert, H.; Fretthold, J.K.; Rainer, F.; Bergman, W.; Beason, D.

1995-02-01

We have completed a preliminary study using filter media tests and filter qualification tests to investigate the effect of shelf-life on HEPA filter performance. Our media studies showed that the tensile strength decreased with age, but the data were not sufficient to establish a shelf-life. Thermogravimetric analyses demonstrated that one manufacturer had media with low tensile strength due to insufficient binder. The filter qualification tests (heated air and overpressure) conducted on different aged filters showed that filter age is not the primary factor affecting filter performance; materials and the construction design have a greater effect. An unexpected finding of our study was that sub-standard HEPA filters have been installed in DOE facilities despite existing regulations and filter qualification tests. We found that the filter with low tensile strength failed the overpressure test. The same filter had passed the heated air test, but left the filter so structurally weak, it was prone to blow-out. We recommend that DOE initiate a filter qualification program to prevent this occurrence

Stable Overexpression of the Constitutive Androstane Receptor Reduces the Requirement for Culture with Dimethyl Sulfoxide for High Drug Metabolism in HepaRG Cells.

Science.gov (United States)

van der Mark, Vincent A; Rudi de Waart, D; Shevchenko, Valery; Elferink, Ronald P J Oude; Chamuleau, Robert A F M; Hoekstra, Ruurdtje

2017-01-01

Dimethylsulfoxide (DMSO) induces cellular differentiation and expression of drug metabolic enzymes in the human liver cell line HepaRG; however, DMSO also induces cell death and interferes with cellular activities. The aim of this study was to examine whether overexpression of the constitutive androstane receptor (CAR, NR1I3), the nuclear receptor controlling various drug metabolism genes, would sufficiently promote differentiation and drug metabolism in HepaRG cells, optionally without using DMSO. By stable lentiviral overexpression of CAR, HepaRG cultures were less affected by DMSO in total protein content and obtained increased resistance to acetaminophen- and amiodarone-induced cell death. Transcript levels of CAR target genes were significantly increased in HepaRG-CAR cultures without DMSO, resulting in increased activities of cytochrome P450 (P450) enzymes and bilirubin conjugation to levels equal or surpassing those of HepaRG cells cultured with DMSO. Unexpectedly, CAR overexpression also increased the activities of non-CAR target P450s, as well as albumin production. In combination with DMSO treatment, CAR overexpression further increased transcript levels and activities of CAR targets. Induction of CYP1A2 and CYP2B6 remained unchanged, whereas CYP3A4 was reduced. Moreover, the metabolism of low-clearance compounds warfarin and prednisolone was increased. In conclusion, CAR overexpression creates a more physiologically relevant environment for studies on hepatic (drug) metabolism and differentiation in HepaRG cells without the utilization of DMSO. DMSO still may be applied to accomplish higher drug metabolism, required for sensitive assays, such as low-clearance studies and identification of (rare) metabolites, whereas reduced total protein content after DMSO culture is diminished by CAR overexpression. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

PPAR agonists reduce steatosis in oleic acid-overloaded HepaRG cells

International Nuclear Information System (INIS)

Rogue, Alexandra; Anthérieu, Sébastien; Vluggens, Aurore; Umbdenstock, Thierry; Claude, Nancy; Moureyre-Spire, Catherine de la; Weaver, Richard J.; Guillouzo, André

2014-01-01

Although non-alcoholic fatty liver disease (NAFLD) is currently the most common form of chronic liver disease there is no pharmacological agent approved for its treatment. Since peroxisome proliferator-activated receptors (PPARs) are closely associated with hepatic lipid metabolism, they seem to play important roles in NAFLD. However, the effects of PPAR agonists on steatosis that is a common pathology associated with NAFLD, remain largely controversial. In this study, the effects of various PPAR agonists, i.e. fenofibrate, bezafibrate, troglitazone, rosiglitazone, muraglitazar and tesaglitazar on oleic acid-induced steatotic HepaRG cells were investigated after a single 24-hour or 2-week repeat treatment. Lipid vesicles stained by Oil-Red O and triglycerides accumulation caused by oleic acid overload, were decreased, by up to 50%, while fatty acid oxidation was induced after 2-week co-treatment with PPAR agonists. The greatest effects on reduction of steatosis were obtained with the dual PPARα/γ agonist muraglitazar. Such improvement of steatosis was associated with up-regulation of genes related to fatty acid oxidation activity and down-regulation of many genes involved in lipogenesis. Moreover, modulation of expression of some nuclear receptor genes, such as FXR, LXRα and CAR, which are potent actors in the control of lipogenesis, was observed and might explain repression of de novo lipogenesis. Conclusion: Altogether, our in vitro data on steatotic HepaRG cells treated with PPAR agonists correlated well with clinical investigations, bringing a proof of concept that drug-induced reversal of steatosis in human can be evaluated in in vitro before conducting long-term and costly in vivo studies in animals and patients. - Highlights: • There is no pharmacological agent approved for the treatment of NAFLD. • This study demonstrates that PPAR agonists can reduce fatty acid-induced steatosis. • Some nuclear receptors appear to be potent actors in the control

PPAR agonists reduce steatosis in oleic acid-overloaded HepaRG cells

Energy Technology Data Exchange (ETDEWEB)

Rogue, Alexandra [Inserm UMR 991, 35043 Rennes Cedex (France); Université de Rennes 1, Faculté des Sciences Pharmaceutiques et Biologiques, 35043 Rennes Cedex (France); Biologie Servier, Gidy (France); Anthérieu, Sébastien; Vluggens, Aurore [Inserm UMR 991, 35043 Rennes Cedex (France); Université de Rennes 1, Faculté des Sciences Pharmaceutiques et Biologiques, 35043 Rennes Cedex (France); Umbdenstock, Thierry [Technologie Servier, Orléans (France); Claude, Nancy [Institut de Recherches Servier, Courbevoie (France); Moureyre-Spire, Catherine de la; Weaver, Richard J. [Biologie Servier, Gidy (France); Guillouzo, André, E-mail: Andre.Guillouzo@univ-rennes1.fr [Inserm UMR 991, 35043 Rennes Cedex (France); Université de Rennes 1, Faculté des Sciences Pharmaceutiques et Biologiques, 35043 Rennes Cedex (France)

2014-04-01

Although non-alcoholic fatty liver disease (NAFLD) is currently the most common form of chronic liver disease there is no pharmacological agent approved for its treatment. Since peroxisome proliferator-activated receptors (PPARs) are closely associated with hepatic lipid metabolism, they seem to play important roles in NAFLD. However, the effects of PPAR agonists on steatosis that is a common pathology associated with NAFLD, remain largely controversial. In this study, the effects of various PPAR agonists, i.e. fenofibrate, bezafibrate, troglitazone, rosiglitazone, muraglitazar and tesaglitazar on oleic acid-induced steatotic HepaRG cells were investigated after a single 24-hour or 2-week repeat treatment. Lipid vesicles stained by Oil-Red O and triglycerides accumulation caused by oleic acid overload, were decreased, by up to 50%, while fatty acid oxidation was induced after 2-week co-treatment with PPAR agonists. The greatest effects on reduction of steatosis were obtained with the dual PPARα/γ agonist muraglitazar. Such improvement of steatosis was associated with up-regulation of genes related to fatty acid oxidation activity and down-regulation of many genes involved in lipogenesis. Moreover, modulation of expression of some nuclear receptor genes, such as FXR, LXRα and CAR, which are potent actors in the control of lipogenesis, was observed and might explain repression of de novo lipogenesis. Conclusion: Altogether, our in vitro data on steatotic HepaRG cells treated with PPAR agonists correlated well with clinical investigations, bringing a proof of concept that drug-induced reversal of steatosis in human can be evaluated in in vitro before conducting long-term and costly in vivo studies in animals and patients. - Highlights: • There is no pharmacological agent approved for the treatment of NAFLD. • This study demonstrates that PPAR agonists can reduce fatty acid-induced steatosis. • Some nuclear receptors appear to be potent actors in the control

Challenges of Membrane Filtration for Produced Water Treatment in Offshore Oil & Gas Production

DEFF Research Database (Denmark)

Jepsen, Kasper Lund; Hansen, Leif; Mai, Christian

2016-01-01

struggling to their fundamental limit, therefore the membrane filtration technology turns to be a potential candidate for zero pollutant discharge. Membrane filtration technology suffers from the notorious fouling problem, where many methods for fouling prevention and removal are explored, the general idea...... is to guarantee that a relatively high permeability can be kept during filtration. Another crucial issue using membrane filtration technology is its huge energy consumption, for which there is little research has been done so far to systematically investigate and optimize the filtration system’s energy efficiency...

EM Task 9 - Centrifugal membrane filtration

International Nuclear Information System (INIS)

Stepan, Daniel J.; Stevens, Bradley G.; Hetland, Melanie D.

1999-01-01

The overall project consists of several integrated research phases related to the applicability, continued development, demonstration, and commercialization of the SpinTek centrifugal membrane filtration process. Work performed during this reporting period consisted of Phase 2 evaluation of the SpinTek centrifugal membrane filtration technology and Phase 3, Technology Partnering. During Phase 1 testing conducted at the EERC using the SpinTek ST-IIL unit operating on a surrogate tank waste, a solids cake developed on the membrane surface. The solids cake was observed where linear membrane velocities were less than 17.5 ft/s and reduced the unobstructed membrane surface area up to 25%, reducing overall filtration performance. The primary goal of the Phase 2 research effort was to enhance filtration performance through the development and testing of alternative turbulence promoter designs. The turbulence promoters were designed to generate a shear force across the entire membrane surface sufficient to maintain a self-cleaning membrane capability and improve filtration efficiency and long-term performance. Specific Phase 2 research activities included the following: System modifications to accommodate an 11-in.-diameter, two-disk rotating membrane assembly; Development and fabrication of alternative turbulence promoter designs; Testing and evaluation of the existing and alternative turbulence promoters under selected operating conditions using a statistically designed test matrix; and Data reduction and analysis; The objective of Phase 3 research was to demonstrate the effectiveness of SpinTek's centrifugal membrane filtration as a pretreatment to remove suspended solids from a liquid waste upstream of 3M's WWL cartridge technology for the selective removal of technetium (Tc)

Electric air filtration: theory, laboratory studies, hardware development, and field evaluations

International Nuclear Information System (INIS)

Bergman, W.; Biermann, A.; Kuhl, W.

1983-09-01

We summarize the results of a seven-year research project for the US Department of Energy (DOE) to develop electric air filters that extend the service life of high-efficiency particulate air (HEPA) filters used in the nuclear industry. This project was unique to Lawrence Livermore National Laboratory (LLNL), and it entailed comprehensive theory, laboratory studies, and hardware development. We present our work in three major areas: (1) theory of and instrumentation for filter test methods, (2) theoretical and laboratory studies of electric air filters, and (3) development and evaluation of eight experimental electric air filters

Filter aids influence on pressure drop across a filtration system

Science.gov (United States)

Hajar, S.; Rashid, M.; Nurnadia, A.; Ammar, M. R.; Hasfalina, C. M.

2017-06-01

Filter aids is commonly used to reduce pressure drop across air filtration system as it helps to increase the efficiency of filtration of accumulated filter cake. Filtration velocity is one of the main parameters that affect the performance of filter aids material. In this study, a formulated filter aids consisting of PreKot™ and activated carbon mixture (designated as PrekotAC) was tested on PTFE filter media under various filtration velocities of 5, 6, and 8 m/min at a constant material loading of 0.2 mg/mm2. Results showed that pressure drop is highly influenced by filtration velocity where higher filtration velocity leads to a higher pressure drop across the filter cake. It was found that PrekotAC performed better in terms of reducing the pressure drop across the filter cake even at the highest filtration velocity. The diversity in different particle size distribution of non-uniform particle size in the formulated PrekotAC mixture presents a higher permeability causes a lower pressure drop across the accumulated filter cake. The finding suggests that PrekotAC is a promising filter aids material that helps reducing the pressure drop across fabric filtration system.

Porous Metal Filters for Gas and Liquid Applications in the Nuclear Industry

International Nuclear Information System (INIS)

Kenneth, Rubow

2009-01-01

Sintered metal media are ideally suited for use in the most demanding industrial applications where long life is required and often other media are not cost-effective solution. As examples, filtration technology utilizing sintered metal media provides excellent performance in numerous liquid/solids and gas/solid separation applications found in the handling and processing of fluids containing radioactive materials. Many types of filter media, ranging from single use (disposable) to semi-permanent, are utilized today for separation of particulate matter. However, semi-permanent media are usually cleanable, either on or off-line, and are intended for sustainable, often multi-year, operating life in harsh environments. These harsh environments, which may involve corrosive fluids, high temperatures, high pressures or pressure spikes, often requiring continuous filtration service, are ideally suited for all-metal filtration systems employing semi-permanent sintered metal media. Sintered metal media, usually fabricated into tubular metal elements, have proven high particle removal efficiency and demonstrated reliability that uniquely afford excellent performance for demanding liquid/solids and gas/solids separation processes. The filter element and, in certain cases, the entire filter are weldable; therefore, the inherent sealing eliminates the need for potentially problematic seals. These media provide a positive barrier to ensure particulate removal to protect downstream equipment, for product separation, and/or to meet health, safety and environmental regulations. Typical applications for sintered metal media include: 1) gas and liquid filter systems used in various nuclear and radioactive waste processing applications, 2) an all-metal High Efficiency Particulate Air (HEPA) filter developed under Department of Energy (DOE) funding as an alternative to traditional HEPA filters fabricated with conventional glass fibers used on High Level Waste (HLW) tank ventilation

Some observations on air filtration

NARCIS (Netherlands)

Kluyver, A.J.; Visser, J.

1950-01-01

1. A method has been developed for testing the filtration efficiency of some filter materials. For each of the materials investigated — cotton wool, stillite and carbon — a suitable filter has been devised. 2. The filtered air was analyzed as to its germ content with the aid of a set of 3 capillary

Pilot-scale tests of HEME and HEPA dissolution process

Energy Technology Data Exchange (ETDEWEB)

Qureshi, Z.H.; Strege, D.K.

1994-06-01

A series of pilot-scale demonstration tests for the dissolution of High Efficiency Mist Eliminators (HEME`s) and High Efficiency Particulate Airfilters (HEPA) were performed on a 1/5th linear scale. These fiberglass filters are to be used in the Defense Waste Processing Facility (DWPF) to decontaminate the effluents from the off-gases generated during the feed preparation process and vitrification. When removed, these filters will be dissolved in the Decontamination Waste Treatment Tank (DWTT) using 5 wt% NaOH solution. The contaminated fiberglass is converted to an aqueous stream which will be transferred to the waste tanks. The filter metal structure will be rinsed with process water before its disposal as low-level solid waste. The pilot-scale study reported here successfully demonstrated a simple one step process using 5 wt% NaOH solution. The proposed process requires the installation of a new water spray ring with 30 nozzles. In addition to the reduced waste generated, the total process time is reduced to 48 hours only (66% saving in time). The pilot-scale tests clearly demonstrated that the dissolution process of HEMEs has two stages - chemical digestion of the filter and mechanical erosion of the digested filter. The digestion is achieved by a boiling 5 wt% caustic solutions, whereas the mechanical break down of the digested filter is successfully achieved by spraying process water on the digested filter. An alternate method of breaking down the digested filter by increased air sparging of the solution was found to be marginally successful are best. The pilot-scale tests also demonstrated that the products of dissolution are easily pumpable by a centrifugal pump.

Pilot-scale tests of HEME and HEPA dissolution process

International Nuclear Information System (INIS)

Qureshi, Z.H.; Strege, D.K.

1994-06-01

A series of pilot-scale demonstration tests for the dissolution of High Efficiency Mist Eliminators (HEME's) and High Efficiency Particulate Airfilters (HEPA) were performed on a 1/5th linear scale. These fiberglass filters are to be used in the Defense Waste Processing Facility (DWPF) to decontaminate the effluents from the off-gases generated during the feed preparation process and vitrification. When removed, these filters will be dissolved in the Decontamination Waste Treatment Tank (DWTT) using 5 wt% NaOH solution. The contaminated fiberglass is converted to an aqueous stream which will be transferred to the waste tanks. The filter metal structure will be rinsed with process water before its disposal as low-level solid waste. The pilot-scale study reported here successfully demonstrated a simple one step process using 5 wt% NaOH solution. The proposed process requires the installation of a new water spray ring with 30 nozzles. In addition to the reduced waste generated, the total process time is reduced to 48 hours only (66% saving in time). The pilot-scale tests clearly demonstrated that the dissolution process of HEMEs has two stages - chemical digestion of the filter and mechanical erosion of the digested filter. The digestion is achieved by a boiling 5 wt% caustic solutions, whereas the mechanical break down of the digested filter is successfully achieved by spraying process water on the digested filter. An alternate method of breaking down the digested filter by increased air sparging of the solution was found to be marginally successful are best. The pilot-scale tests also demonstrated that the products of dissolution are easily pumpable by a centrifugal pump

Investigation of pressure transients in nuclear filtration systems: construction details of a large shock tube

International Nuclear Information System (INIS)

Smith, P.R.; Gregory, W.S.

1980-04-01

This report documents the construction of a 0.914-m (36-in.)-dia. shock tube on the New Mexico State University caompus. Highly variable low-grade explosions can be simulated with the shock tube. We plan to investigate the response of nuclear facility ventilation system components to low-grade explosions. Components of particular interest are high-capacity, high efficiency paticulate air (HEPA) filters. Shock tube construction details, operating principles, firing sequence, and preliminary results are reported

In-duct countermeasures for reducing fire-generated-smoke-aerosol exposure to HEPA filters

International Nuclear Information System (INIS)

Alvares, N.J.; Beason, D.G.; Ford, H.W.

1978-01-01

An experimental program was conducted to assess the endurance and lifetime of HEPA filters exposed to fire-generated aerosols, and to reduce the aerosol exposure by installing engineering countermeasures in the duct between the fire source and HEPA filters. Large cribs of wood and other potential fuels of interest were ''forcefully burned'' in a partially ventilated enclosure. In a ''forceful burn'' the crib of fuel is continuously exposed to an energetic premixed methane flame during the entire experimental period. This tactic serves two purposes: it optimizes the production of smoke rich in unburned pyrolyzates which provides severe exposure to the filters, and it facilitates the ignition and enhances the combustion of cribs formed with synthetic polymers. The experiments were conducted in an enclosure specifically designed and instrumented for fire tests. The test cell has a volume of 100 m 3 and includes instrumentation to measure the internal temperature distribution, pressure, thermal radiation field, flow fields, gas concentration, particulate size distribution and mass, fuel weight loss, inlet and exit air velocities, and smoke optical density. The countermeasure techniques include the use of passively operated sprinkler systems in the fire test cell, of fine and dense water scrubbing sprays, and of rolling prefiltration systems in the exit duct of the fire test cell. Of the countermeasures surveyed, the rolling prefilter system showed the most promise. This paper concentrates on the effect of control variables; i.e., enclosure air supply, fuel composition and crib porosity on the combustion response; i.e., crib burning rate, enclosure temperature rise, oxygen consumption, and CO, CO 2 and total hydrocarbon production. A discussion of the attempts to rationalize smoke aerosol properties will be included along with results from the effect of countermeasure application on HEPA filter lifetimes

Effects on the efficiency of activated carbon on exposure to welding fumes

Energy Technology Data Exchange (ETDEWEB)

Ghosh, D. [Southern Company Services, Inc., Birmingham, AL (United States)

1995-02-01

It is the intention of this paper to document that certain types of welding fumes have little or no effect on the effectiveness of the carbon filter air filtration efficiency when directly exposed to a controlled amount of welding fumes for a short-term period. The welding processes studied were restricted to shielded metal arc welding (SMAW), flux cored arc welding (FCAW), gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) processes. Contrary to the SMAW and FCAW processes, the GTAW (or TIG) and the GMAW (or MIG) welding processes do not require the use of flux as part of the overall process. Credit was taken for these processes occurring in inert gas environments and producing minimal amount of smoke. It was concluded that a study involving the SMAW process would also envelop the effects of the TIG and MIG welding processes. The quantity of welding fumes generated during the arc welding process is a function of the particular process, the size and type of electrode, welding machine amperage, and operator proficiency. For this study, the amount of welding for specific testing was equated to the amount of welding normally conducted during plant unit outages. Different welding electrodes were also evaluated, and the subsequent testing was limited to an E7018 electrode which was judged to be representative of all carbon and stainless steel electrodes commonly used at the site. The effect of welding fumes on activated charcoal was tested using a filtration unit complete with prefilters, upstream and downstream high efficiency particulate air (HEPA) filters, and a carbon adsorber section. The complete system was field tested in accordance with ANSI N510 standards prior to exposing the filters and the adsorber bed to welding fumes. The carbon samples were tested at an established laboratory using ASTM D3803-1989 standards.

Electrospun ceramic fibermats for filtration applications in lunar missions for in-habitat applications

Science.gov (United States)

Biswas, Apratim

In the absence of atmosphere and hydrosphere, there are few collisions between dust particles in the lunar environment. Further, particles become charged in presence of cosmic rays and similarly charged particles repel each other. Hence particles retain sharp edges and often have high aspect ratios. When exposed to lunar dust, humans show symptoms similar to hay fever. Such particles are also damaging to equipment. Humans and robots, used in operations, can bring such dust particles inside the human habitat making them airborne. High efficiency particulate air (HEPA) filters provide an effective way to trap such particles. But due to environment conditions, polymer based filters are susceptible to mechanical erosion. The presence of high energy radiation, due to the absence of atmosphere and magnetic fields, is also damaging to polymers. Ceramic materials are resistant to abrasion and radiation and hence were chosen as the preferred class of materials for the filtration media. Among all the ceramics, TiO2 was selected for its photocatalytic activity which may play a key role in energy-efficient survival in space or lunar stations. Such fibers are multi-functional with the advantage of self-cleaning property in presence of radiation. However ceramic fibers, including TiO 2 fibers, have a significant disadvantage of their own. They are brittle and were considered too prone to failure to be successfully used as a filtration media when they reach nanometer dimensions. This dissertation describes the advances in fabrication and understanding of fundamentals in overcoming these challenges. In absence of crack initiation sites, amorphous ceramic fibers have near theoretical strength and strain to failure. Amorphous TiO2 -SiO2 fibermats, with lower flaw populations and exceptional surface quality, have been developed. They can be rolled to a radius of curvature of 3.4 mm -- exhibiting flexibility. The fibermats are also mechanically robust and can withstand the stress

Application of Colloidal Filtration Theory on Textile Fibrous Media: Effect of Fiber Orientation on Bacterial Removal Efficiency and Attachment

Science.gov (United States)

Roy, Sukumar; Ghosh, Subrata; Bhowmick, Niranjan

2018-05-01

A mechanism to remove the Pseudomonas bacteria from contaminated water by using textile fibrous media has been proposed in this article. The attachment of Pseudomonas bacteria on nylon fibrous media was studied in laboratory column experiment. A systematic study was carried out to investigate the attachment of bacteria on the fibrous material as a function of fiber orientation to the direction of the liquid flow. Three types of textiles media with different orientation fiber were selected for the experiment (i.e. 0°, 45° and 90°). It was found that the bacteria removal efficiency was comparatively higher at 90° orientation as compared to that of 45° and 0° orientation of fibrous media, suggesting that the removal efficiency of bacteria (1 - Fp) was depended on fiber orientation. The removal trends were explained on the basis of colloidal filtration theory. This is due to the higher single collector contact efficiency and attachment/collision efficiency as observed from the experimental data of removal efficiency.

Magnetic-seeding filtration

International Nuclear Information System (INIS)

Ying, T.Y.; Chin, C.J.; Lu, S.C.; Yiacoumi, S.

1997-10-01

Magnetic-seeding filtration consists of two steps: heterogeneous particle flocculation of magnetic and nonmagnetic particles in a stirred tank and high-gradient magnetic filtration (HGMF). The effects of various parameters affecting magnetic-seeding filtration (HGMF). The effects of various parameters affecting magnetic seeding filtration are theoretically and experimentally investigated. A trajectory model that includes hydrodynamic resistance, van der Waals, and electrostatic forces is developed to calculate the flocculation frequency in a turbulent-shear regime. Fractal dimension is introduced to simulate the open structure of aggregates. A magnetic-filtration model that consists of trajectory analysis, a particle build-up model, a breakthrough model, and a bivariate population-balance model is developed to predict the breakthrough curve of magnetic-seeding filtration. A good agreement between modeling results and experimental data is obtained. The results show that the model developed in this study can be used to predict the performance of magnetic-seeding filtration without using empirical coefficients or fitting parameters. 35 refs., 7 figs., 1 tab

BWR condensate filtration studies

International Nuclear Information System (INIS)

Wilson, J.A.; Pasricha, A.; Rekart, T.E.

1993-09-01

Poor removal of particulate corrosion products (especially iron) from condensate is one of the major problems in BWR systems. The presence of activated corrosion products creates ''hot spots'' and increases piping dose rates. Also, fuel efficiency is reduced and the risk of fuel failure is increased by the deposit of corrosion products on the fuel. Because of these concerns, current EPRI guidelines call for a maximum of 2 ppb of iron in the reactor feedwater with a level of 0.5 ppb being especially desirable. It has become clear that conventional deep bed resins are incapable of meeting these levels. While installation of prefilter systems is an option, it would be more economical for plants with naked deep beds to find an improved bead resin for use in existing systems. BWR condensate filtration technologies are being tested on a condensate side stream at Hope Creek Nuclear Generating Station. After two years of testing, hollow fiber filters (HFF) and fiber matrix filters (FMF), and low crosslink cation resin, all provide acceptable results. The results are presented for pressure drop, filtration efficiency, and water quality measurements. The costs are compared for backwashable non-precoat HFF and FMF. Results are also presented for full deep bed vessel tests of the low crosslink cation resin

Performance of 1000- and 1800- cfm HEPA filters on long exposure to low atmospheric dust loadings, II

International Nuclear Information System (INIS)

First, M.W.; Rudnick, S.N.

1981-01-01

Comparative tests were made to evaluate the performance characteristics of American- and European-design HEPA filters when exposed, for a number of years, to aerosols characteristic of nuclear and biohazard service. Although some of the European-design filters were operated at their rated airflow capacity of 1800 cfm, some were downrated to 1000 cfm to determine if their service life could be more than tripled compared to conventional 1000-cfm Americal-design HEPA filters, as filter theory predicts. Initial results indicate, however, that for the ambient aerosol used in this study, a European-design filter has a service life of only 1.6 times greater than an American-design filter when both operate at 1000 cfm. Further tests are in progress to verify this result

Development of an Electrochemical Ceramic Membrane Filtration System for Efficient Contaminant Removal from Waters.

Science.gov (United States)

Zheng, Junjian; Wang, Zhiwei; Ma, Jinxing; Xu, Shaoping; Wu, Zhichao

2018-04-03

Inability to remove low-molecular-weight anthropogenic contaminants is a critical issue in low-pressure membrane filtration processes for water treatment. In this work, a novel electrochemical ceramic membrane filtration (ECMF) system using TiO 2 @SnO 2 -Sb anode was developed for removing persistent p-chloroaniline (PCA). Results showed that the ECMF system achieved efficient removal of PCA from contaminated waters. At a charging voltage of 3 V, the PCA removal rate of TiO 2 @SnO 2 -Sb ECMF system under flow-through mode was 2.4 times that of flow-by mode. The energy consumption for 50% of PCA removal for TiO 2 @SnO 2 -Sb ECMF at 3 V under flow-through mode was 0.38 Wh/L, much lower than that of flow-by operation (1.5 Wh/L), which was attributed to the improved utilization of the surface adsorbed HO· and dissociated HO· driven by the enhanced mass transfer of PCA toward the anode surface. Benefiting from the increased production of reactive oxygen species such as O 2 •- , H 2 O 2 , and HO· arising from excitation of anatase TiO 2 , TiO 2 @SnO 2 -Sb ECMF exhibited a superior electrocatalytic activity to the SnO 2 -Sb ECMF system. The degradation pathways of PCA initiated by OH· attack were further proposed, with the biodegradable short-chain carboxylic acids (mainly formic, acetic, and oxalic acids) identified as the dominant oxidized products. These results highlight the potential of the ECMF system for cost-effective water purification.

Numerical investigation of adhesion effects on solid particles filtration efficiency

Science.gov (United States)

Shaffee, Amira; Luckham, Paul; Matar, Omar K.

2017-11-01

Our work investigate the effectiveness of particle filtration process, in particular using a fully-coupled Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) approach involving poly-dispersed, adhesive solid particles. We found that an increase in particle adhesion reduces solid production through the opening of a wire-wrap type filter. Over time, as particle agglomerates continuously deposit on top of the filter, layer upon layer of particles is built on top of the filter, forming a particle pack. It is observed that with increasing particle adhesion, the pack height build up also increases and hence decreases the average particle volume fraction of the pack. This trend suggests higher porosity and looser packing of solid particles within the pack with increased adhesion. Furthermore, we found that the pressure drop for adhesive case is lower compared to non-adhesive case. Our results suggest agglomerating solid particles has beneficial effects on particle filtration. One important application of these findings is towards designing and optimizing sand control process for a hydrocarbon well with excessive sand production which is major challenge in oil and gas industry. Funding from PETRONAS and RAEng UK for Research Chair (OKM) gratefully acknowledged.

Portable Hybrid Powered Water Filtration Device

Directory of Open Access Journals (Sweden)

Maria Lourdes V. Balansay

2015-08-01

Full Text Available The existing water filtration device has features that can be developed to be more useful and functional during emergency situations. The project’s development has been aided by following provisions in PEC, NEC, NEMA and Philippine National Standard for Safe Drinking Water provide standards for the construction of the project. These standards protect both the prototype and the user. These also served as guide for the maintenance of every component. The design of the portable hybrid powered water filtration device shows that the project has more advanced features such as portability and the power supply used such as photovoltaic module solar cells and manually operated generator. This also shows its effectiveness and reliability based on the results of discharging test, water quality test and water production test. Based on analysis of the overall financial aspects, the machine can be profitable and the amount of revenue and operating cost will increase as years pass. Using the proper machine/ tools and methods of fabrication helps in easy assembly of the project. The materials and components used are cost effective and efficient. The best time for charging the battery using solar panel is 9:00 am onwards while the hand crank generator is too slow because the generated current is little. The water filtration device is very efficient regarding the operating hours and water production. The machine may have a great effect to society and economy in generation of clean available water at less cost.

Filtration of polydispersed colloids

International Nuclear Information System (INIS)

Nuttall, H.E.

1988-01-01

In this study, the dynamic microscopic form of the population balance model is applied to the problem of polydispersed particle capture in one spatial diffusion. This mathematical modeling approach can be applied to the difficult and potentially important problem of particulate (radiocolloid) transport in the groundwater surrounding a nuclear waste disposal site. To demonstrate the population balance methodology, the equations were developed and used to investigate transport and capture of polydispersed colloids in packed columns. Modeling simulations were compared to experimental column data. The multidimensional form of the population balance equation was used to analyze the transport and capture of polydispersed colloids. A numerical model was developed to describe transport of polydispersed colloids through a one-dimensional porous region. The effects of various size distributions were investigated in terms of capture efficiency. For simulating the column data, it was found by trial and error that as part of the population balance model a linear size dependent filtration function gave a good fit to the measured colloid concentration profile. The effects of constant versus size dependent filtration coefficients were compared and the differences illustrated by the calculated colloid profile within the column. Also observed from the model calculations was the dramatically changing liquid-phase colloid-size distribution which was plotted as a function of position down the column. This modeling approach was excellent for describing and understanding microscopic filtration in porous media

Water quality and treatment of river bank filtrate

Directory of Open Access Journals (Sweden)

W. W. J. M. de Vet

2010-06-01

Full Text Available In drinking water production, river bank filtration has the advantages of dampening peak concentrations of many dissolved components, substantially removing many micropollutants and removing, virtually completely, the pathogens and suspended solids. The production aquifer is not only fed by the river bank infiltrate but also by water percolating through covering layers. In the polder areas, these top layers consist of peat and deposits from river sediments and sea intrusions.

This paper discusses the origin and fate of macro components in river bank filtrate, based on extensive full-scale measurements in well fields and treatment systems of the Drinking Water Company Oasen in the Netherlands. First, it clarifies and illustrates redox reactions and the mixing of river bank filtrate and PW as the dominant processes determining the raw water quality for drinking water production. Next, full-scale results are elaborated on to evaluate trickling filtration as an efficient and proven one-step process to remove methane, iron, ammonium and manganese. The interaction of methane and manganese removal with nitrification in these systems is further analyzed. Methane is mostly stripped during trickling filtration and its removal hardly interferes with nitrification. Under specific conditions, microbial manganese removal may play a dominant role.

Particle counter as a tool to control pre-hydrolyzed coagulant dosing and rapid filtration efficiency in a conventional treatment system.

Science.gov (United States)

Gumińska, Jolanta; Kłos, Marcin

2015-01-01

Filtration efficiency in a conventional water treatment system was analyzed in the context of pre-hydrolyzed coagulant overdosing. Two commercial coagulants of different aluminum speciation were tested. A study was carried out at a water treatment plant supplied with raw water of variable quality. The lack of stability of water quality caused many problems with maintaining the optimal coagulant dose. The achieved results show that the type of coagulant had a very strong influence on the effectiveness of filtration resulting from the application of an improper coagulant dose. The overdosing of high basicity coagulant (PAC85) caused a significant increase of fine particles in the outflow from the sedimentation tanks, which could not be retained in the filter bed due to high surface charge and the small size of hydrolysis products. When using a coagulant of lower basicity (PAC70), it was much easier to control the dose of coagulant and to adjust it to the changing water quality.

A Brief Review of Filtration Studies for Waste Treatment at the Hanford Site

Energy Technology Data Exchange (ETDEWEB)

Daniel, Richard C.; Schonewill, Philip P.; Shimskey, Rick W.; Peterson, Reid A.

2010-12-01

This document completes the requirements of Milestone 1-2, PNNL Draft Literature Review, discussed in the scope of work outlined in the EM-31 Support Project task plan WP-2.3.6-2010-1. The focus of task WP 2.3.6 is to improve the U.S. Department of Energy’s (DOE’s) understanding of filtration operations for high-level waste (HLW) to enhance filtration and cleaning efficiencies, thereby increasing process throughput and reducing the sodium demand (through acid neutralization). Developing the processes for fulfilling the cleaning/backpulsing requirements will result in more efficient operations for both the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and the Savannah River Site (SRS), thereby increasing throughput by limiting cleaning cycles. The purpose of this document is to summarize Pacific Northwest National Laboratory’s (PNNL’s) literature review of historical filtration testing at the laboratory and of testing found in peer-reviewed journals. Eventually, the contents of this document will be merged with a literature review by SRS to produce a summary report for DOE of the results of previous filtration testing at the laboratories and the types of testing that still need to be completed to address the questions about improved filtration performance at WTP and SRS. To this end, this report presents 1) a review of the current state of crossflow filtration knowledge available in the peer-reviewed literature, 2) a detailed review of PNNL-related filtration studies specific to the Hanford site, and 3) an overview of current waste filtration models developed by PNNL and suggested avenues for future model development.

Development of electromagnetic filtration in the feed water circuits

International Nuclear Information System (INIS)

Dolle, L.

1980-01-01

Electromagnetic filtration in the feed water circuit of the steam generators in nuclear power plants is efficient towards insoluble corrosion products. The principle of electromagnetic filtration is shortly recalled and the results of corresponding development work are summarized. The magnitude of water volumes to be treated on the two priviledged parts of the circuit are estimated. These parts are on the feed water tank level and on the blow-down of the steam generator. The practical applications are discussed [fr

Transparent Nanofibrous Mesh Self-Assembled from Molecular LEGOs for High Efficiency Air Filtration with New Functionalities.

Science.gov (United States)

Singh, Varun Kumar; Ravi, Sai Kishore; Sun, Wanxin; Tan, Swee Ching

2017-02-01

Alarming levels of particulate matter pollution in air pose a serious health threat in several countries, therefore intriguing a strong need for an economic and a viable technology of air filtration. Current air purification technology is rather expensive with certain types even having the risk of emitting hazardous by-products. The authors have developed a multifunctional air filter inspired from the nasal hairs possessing an ability to specifically trap/exhale the foreign particles and allergens while still letting the air flow. This design is achieved by introducing different functionalities at different dimensional scale employing a bottom-up approach starting with an organic molecule which is further self-organized to form nanoparticles and ultimately to a nanofibrous mesh. While the molecular building block inherently possesses the property of shielding Ultraviolet (UV) rays, the nanofibrous mesh built up from it aids in trapping the particulate matter while maintaining good air flow. By controlling the concentration of the organic molecule, the formation of fibers has been enabled in the nanoscale regime to obtain high particle-capture possibilities. The self-assembled nanofibrous filter thus designed has achieved a high filtration efficiency of ≈90% for the PM 2.5 particle in congruence with the ability to block the harmful UV radiations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Software Verification and Validation Test Report for the HEPA filter Differential Pressure Fan Interlock System

International Nuclear Information System (INIS)

ERMI, A.M.

2000-01-01

The HEPA Filter Differential Pressure Fan Interlock System PLC ladder logic software was tested using a Software Verification and Validation (VandV) Test Plan as required by the ''Computer Software Quality Assurance Requirements''. The purpose of his document is to report on the results of the software qualification

Measurement of gamma activity from the PUREX stack, Number 296-A-10, HEPA filters

International Nuclear Information System (INIS)

Barnett, J.M.

1995-11-01

In response to the Environmental Protection Agency's requirements for evaluating radioactive emissions from stacks, this test plan was developed. The test plan employs the use of low resolution (NaI) portable gamma spectrometry to identify and measure gamma emitting radionuclides from HEPA filters. The test description, expected results, and test set-up and steps are discussed

Production environment in mineral water plants; Mineral water kojo no seisan kankyo

Energy Technology Data Exchange (ETDEWEB)

Yoshimatsu, A. [Morinaga Engineering Company, Tokyo (Japan)

1996-01-05

This paper summarizes mineral waters as commercial products, and the manufacturing facilities thereof. The most widely used pattern of packaging mineral waters is to use either PET bottle or back-in box. The manufacturing process consists generally of: rough filtration of natural water, storage, activated carbon filtration, filtration, sterilization, ultrafine filtration, warm water bottling, capping, cooling, cartoning, storage, and shipment. The rough filtration removes sands. The activated carbon filtration removes water soluble organics. The sterilization is carried out under conditions of retaining the water at 75{degree}C for 15 seconds or retaining at 120 to 140{degree}C for 2 seconds. The ultrafine filtration uses a ceramic filter with a thickness of 0.2{mu}m. Sterilizing harmful microorganisms uses heating operation and filters to remove bacteria. An example may be cited that uses a bio-clean room for the purpose of controlling the harmful microorganisms. Subject microorganisms include a variety of viruses, rickettsia, bacteria, and fungi. The super-high performance (HEPA) filter used in the sterilization is demanded of collecting dusts with sizes of 0.3{mu}m or larger at a collection efficiency of 99.97% or higher. 3 refs., 4 figs., 1 tab.

Filter Efficiency and Leak Testing of Returned ISS Bacterial Filter Elements After 2.5 Years of Continuous Operation

Science.gov (United States)

Green, Robert D.; Agui, Juan H.; Berger, Gordon M.; Vijayakumar, R.; Perry, Jay L.

2016-01-01

The atmosphere revitalization equipment aboard the International Space Station (ISS) and future deep space exploration vehicles provides the vital functions of maintaining a habitable environment for the crew as well as protecting the hardware from fouling by suspended particulate matter. Providing these functions are challenging in pressurized spacecraft cabins because no outside air ventilation is possible and a larger particulate load is imposed on the filtration system due to lack of sedimentation in reduced gravity conditions. The ISS Environmental Control and Life Support (ECLS) system architecture in the U.S. Segment uses a distributed particulate filtration approach consisting of traditional High-Efficiency Particulate Adsorption (HEPA) filters deployed at multiple locations in each module. These filters are referred to as Bacteria Filter Elements (BFEs). As more experience has been gained with ISS operations, the BFE service life, which was initially one year, has been extended to two to five years, dependent on the location in the U.S. Segment. In previous work we developed a test facility and test protocol for leak testing the ISS BFEs. For this work, we present results of leak testing a sample set of returned BFEs with a service life of 2.5 years, along with particulate removal efficiency and pressure drop measurements. The results can potentially be utilized by the ISS Program to ascertain whether the present replacement interval can be maintained or extended to balance the on-ground filter inventory with extension of the lifetime of ISS to 2024. These results can also provide meaningful guidance for particulate filter designs under consideration for future deep space exploration missions.

Forced-air warming design: evaluation of intake filtration, internal microbial buildup, and airborne-contamination emissions.

Science.gov (United States)

Reed, Mike; Kimberger, Oliver; McGovern, Paul D; Albrecht, Mark C

2013-08-01

Forced-air warming devices are effective for the prevention of surgical hypothermia. However, these devices intake nonsterile floor-level air, and it is unknown whether they have adequate filtration measures to prevent the internal buildup or emission of microbial contaminants. We rated the intake filtration efficiency of a popular current-generation forced-air warming device (Bair Hugger model 750, Arizant Healthcare) using a monodisperse sodium chloride aerosol in the laboratory. We further sampled 23 forced-air warming devices (same model) in daily hospital use for internal microbial buildup and airborne-contamination emissions via swabbing and particle counting. Laboratory testing found the intake filter to be 63.8% efficient. Swabbing detected microorganisms within 100% of the forced-air warming blowers sampled, with isolates of coagulase-negative staphylococci, mold, and micrococci identified. Particle counting showed 96% of forced-air warming blowers to be emitting significant levels of internally generated airborne contaminants out of the hose end. These findings highlight the need for upgraded intake filtration, preferably high-efficiency particulate air filtration (99.97% efficient), on current-generation forced-air warming devices to reduce contamination buildup and emission risks.

Aging assessment of nuclear air-treatment system HEPA filters and adsorbers

International Nuclear Information System (INIS)

Winegardner, W.K.

1993-08-01

A Phase I aging assessment of high-efficiency particulate air (HEPA) filters and activated carbon gas adsorption units (adsorbers) was performed by the Pacific Northwest Laboratory (PNL) as part of the US Nuclear Regulatory Commission's (NRC) Nuclear Plant Aging Research (NPAR) Program. Information concerning design features; failure experience; aging mechanisms, effects, and stressors; and surveillance and monitoring methods for these key air-treatment system components was compiled. Over 1100 failures, or 12 percent of the filter installations, were reported as part of a Department of Energy (DOE) survey. Investigators from other national laboratories have suggested that aging effects could have contributed to over 80 percent of these failures. Tensile strength tests on aged filter media specimens indicated a decrease in strength. Filter aging mechanisms range from those associated with particle loading to reactions that alter properties of sealants and gaskets. Low radioiodine decontamination factors associated with the Three Mile Island (TMI) accident were attributed to the premature aging of the carbon in the adsorbers. Mechanisms that can lead to impaired adsorber performance include oxidation as well as the loss of potentially available active sites as a result of the adsorption of pollutants. Stressors include heat, moisture, radiation, and airborne particles and contaminants

Cross-flow micro-filtration using ceramic membranes

International Nuclear Information System (INIS)

Thern, Gerardo G.; Marajofsky, Adolfo; Rossi, Federico; La Gamma, Ana M.; Chocron, Mauricio

2004-01-01

Pressurized Heavy Water Reactors have a system devoted to the purification and upgrading of the collected heavy water leaks. The purification train is fed with different degradation ratios (D 2 O/H 2 O), activities and impurities. The water is distilled in a packed bed column filled with a mesh type packing. With the purpose of minimizing the column stack corrosion, the water is pre-treated in a train consisting on an activated charcoal bed-strong cationic-anionic resin and a final polishing anionic bed resin. Traces of oils are retained by the charcoal bed but some of them pass through and could be responsible for the resins fouling. The process of micro filtration using ceramic materials is particularly applied to the treatment of waters with oil micro droplets. We describe the development stages of single and double layer filtration ceramic tubes, their characterization and the adaptation to test equipment. The efficiency was evaluated by means of tangential ('cross-flow') filtration of aqueous solutions containing dodecane at the micrograms per ml concentration level. This compound simulates the properties of a typical oil contaminant. A 100-fold reduction in the amount of dodecane in water was observed after the filtration treatment. (author)

GSPEL - Air Filtration Laboratory

Data.gov (United States)

Federal Laboratory Consortium — Evaluation capabilities for air filtration devicesThe Air Filtration Lab provides testing of air filtration devices to demonstrate and validate new or legacy system...

Absolute air filtering equipment in the nuclear industrie. Design - Safety - Experience

International Nuclear Information System (INIS)

Lucas, J.C.

1977-01-01

The problems encountered in the design of absolute filters (HEPA FILTERS) are presented: glass-fibre filter papers; standards and characteristics: efficiency, fire-resistance, humidity-resistance, radiation-resistance, etc; various types of paper folding: deep folds and small folds, dihedrally mounted; filtering elements; designs; characteristics and quality control; The design of filtration equipment is also analysed: mounting in metal or concrete casings. French and American designs (Regulatory Guide 1-52); and gas-tight casings allowing contaminated filters to be renewed without breaking the gas-tight seal

Evaluation of self-contained HEPA filter

Energy Technology Data Exchange (ETDEWEB)

Arndt, T.E. [Westinghouse Hanford Company, Richland, WA (United States)

1995-02-01

This paper presents the results of an evaluation of a self-contained high-efficiency particulate air filter (SHEPA) used in nuclear applications. A SCHEPA consists of filter medium encapsulated in a casing that is part of the system boundary. The SCHEPA filter serves as a combination of filter housing and filter. The filter medium is attached directly to the casing using adhesive as a bonding agent. A cylindrical connection in the middle of the end caps connects the filter assembly to adjoining ductwork. The SCHEPA must perform the functions of a filter housing, filter frame, and filter. It was recognized that the codes and standards do not address the SCHEPA specifically. Therefore, the investigation evaluated the SCHEPA against current codes and standards related to the functional requirements of an air-cleaning system. The specific standards used are required by DOE Order 6430.1A{sup 1} and include ASME N509{sup 3}, ASME N510{sup 4}, ERDA 76-21{sup 5}, MIL-F-51068F{sup 6}, NFPA 90A, {sup 7} and NFPA 91{sup 8}. The evaluation does not address whether the SCHEPA as a standard (off-the-shelf) filter could be upgraded to meet the current code requirements for an air-cleaning unit. The evaluation also did not consider how the SCHEPA was used in a system (e.g., whether it was under positive or negative pressure or whether it served as an air inlet filter to prevent contamination releases under system pressurization). The results of the evaluation show that, the SCHEPA filter does not meet design, fabrication, testing, and documentation requirements of ASME N509{sup 3} and ASME N510{sup 4}. The paper will identify these deficiencies. Specific exhaust system requirements and application should be considered when an evaluation of the SCHEPA filter is being performed in existing systems. When new designs are being comtemplated, other types of HEPA filter housings can be used in lieu of the SCHEPA filter.

40 CFR 141.173 - Filtration.

Science.gov (United States)

2010-07-01

... PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving 10,000 or More People § 141.173 Filtration. A public water system subject to the requirements of this subpart that does... treatment, direct filtration, slow sand filtration, or diatomaceous earth filtration. A public water system...

Filtration aids in uranium ore processing

International Nuclear Information System (INIS)

Ford, H.L.; Levine, N.M.; Risdon, A.R.

1975-01-01

A process of improving the filtration efficiency and separation of uranium ore pulps obtained by carbonate leaching of uranium ore which comprises treating said ore pulps with an aqueous solution of hydroxyalkyl guar selected from the group consisting of hydroxyethyl and hydroxypropyl guar in the amount of 0.1 and 2.0 pounds of hydroxyalkyl guar per ton of uranium ore

The histone deacetylase inhibiting drug Entinostat induces lipid accumulation in differentiated HepaRG cells

Science.gov (United States)

Nunn, Abigail D. G.; Scopigno, Tullio; Pediconi, Natalia; Levrero, Massimo; Hagman, Henning; Kiskis, Juris; Enejder, Annika

2016-06-01

Dietary overload of toxic, free metabolic intermediates leads to disrupted insulin signalling and fatty liver disease. However, it was recently reported that this pathway might not be universal: depletion of histone deacetylase (HDAC) enhances insulin sensitivity alongside hepatic lipid accumulation in mice, but the mechanistic role of microscopic lipid structure in this effect remains unclear. Here we study the effect of Entinostat, a synthetic HDAC inhibitor undergoing clinical trials, on hepatic lipid metabolism in the paradigmatic HepaRG liver cell line. Specifically, we statistically quantify lipid droplet morphology at single cell level utilizing label-free microscopy, coherent anti-Stokes Raman scattering, supported by gene expression. We observe Entinostat efficiently rerouting carbohydrates and free-fatty acids into lipid droplets, upregulating lipid coat protein gene Plin4, and relocating droplets nearer to the nucleus. Our results demonstrate the power of Entinostat to promote lipid synthesis and storage, allowing reduced systemic sugar levels and sequestration of toxic metabolites within protected protein-coated droplets, suggesting a potential therapeutic strategy for diseases such as diabetes and metabolic syndrome.

Chest CT using spectral filtration: radiation dose, image quality, and spectrum of clinical utility

Energy Technology Data Exchange (ETDEWEB)

Braun, Franziska M.; Johnson, Thorsten R.C.; Sommer, Wieland H.; Thierfelder, Kolja M.; Meinel, Felix G. [University Hospital Munich, Institute for Clinical Radiology, Munich (Germany)

2015-06-01

To determine the radiation dose, image quality, and clinical utility of non-enhanced chest CT with spectral filtration. We retrospectively analysed 25 non-contrast chest CT examinations acquired with spectral filtration (tin-filtered Sn100 kVp spectrum) compared to 25 examinations acquired without spectral filtration (120 kV). Radiation metrics were compared. Image noise was measured. Contrast-to-noise-ratio (CNR) and figure-of-merit (FOM) were calculated. Diagnostic confidence for the assessment of various thoracic pathologies was rated by two independent readers. Effective chest diameters were comparable between groups (P = 0.613). In spectral filtration CT, median CTDI{sub vol}, DLP, and size-specific dose estimate (SSDE) were reduced (0.46 vs. 4.3 mGy, 16 vs. 141 mGy*cm, and 0.65 vs. 5.9 mGy, all P < 0.001). Spectral filtration CT had higher image noise (21.3 vs. 13.2 HU, P < 0.001) and lower CNR (47.2 vs. 75.3, P < 0.001), but was more dose-efficient (FOM 10,659 vs. 2,231/mSv, P < 0.001). Diagnostic confidence for parenchymal lung disease and osseous pathologies was lower with spectral filtration CT, but no significant difference was found for pleural pathologies, pulmonary nodules, or pneumonia. Non-contrast chest CT using spectral filtration appears to be sufficient for the assessment of a considerable spectrum of thoracic pathologies, while providing superior dose efficiency, allowing for substantial radiation dose reduction. (orig.)

On some Filtration Procedure for Jump Markov Process Observed in White Gaussian Noise

OpenAIRE

Khas'minskii, Rafail Z.; Lazareva, Betty V.

1992-01-01

The importance of optimal filtration problem for Markov chain with two states observed in Gaussian white noise (GWN) for a lot of concrete technical problems is well known. The equation for a posterior probability $\\pi(t)$ of one of the states was obtained many years ago. The aim of this paper is to study a simple filtration method. It is shown that this simplified filtration is asymptotically efficient in some sense if the diffusion constant of the GWN goes to 0. Some advantages of this proc...

Impact of isomalathion on malathion cytotoxicity and genotoxicity in human HepaRG cells.

OpenAIRE

Josse , Rozenn; Sharanek , Ahmad; Savary , Camille C; Guillouzo , André

2014-01-01

International audience; Isomalathion is a major impurity of technical grade malathion, one of the most abundantly applied insecticides; however little is known about its hepatotoxicity. In the present study, cytotoxicity and genotoxicity of malathion and isomalathion either individually or in combination, were assessed using the metabolically competent human liver HepaRG cell line. Isomalathion reduced cell viability starting at a 100 μM concentration after a 24h exposure. It also significant...

Results from Evaluation of Proposed ASME AG-1 Section FI Metal Media Filters - 13063

Energy Technology Data Exchange (ETDEWEB)

Wilson, John A.; Giffin, Paxton K.; Parsons, Michael S.; Waggoner, Charles A. [Institute for Clean Energy Technology, Mississippi State University, 205 Research Blvd Starkville, MS 39759 (United States)

2013-07-01

High efficiency particulate air (HEPA) filtration technology is commonly used in Department of Energy (DOE) facilities that require control of radioactive particulate matter (PM) emissions due to treatment or management of radioactive materials. Although HEPA technology typically makes use of glass fiber media, metal and ceramic media filters are also capable of filtering efficiencies beyond the required 99.97%. Sintered metal fiber filters are good candidates for use in DOE facilities due to their resistance to corrosive environments and resilience at high temperature and elevated levels of relative humidity. Their strength can protect them from high differential pressure or pressure spikes and allow for back pulse cleaning, extending filter lifetime. Use of these filters has the potential to reduce the cost of filtration in DOE facilities due to life cycle cost savings. ASME AG-1 section FI has not been approved due to a lack of protocols and performance criteria for qualifying section FI filters. The Institute for Clean Energy Technology (ICET) with the aid of the FI project team has developed a Section FI test stand and test plan capable of assisting in the qualification ASME AG-1 section FI filters. Testing done at ICET using the FI test stand evaluates resistance to rated air flow, test aerosol penetration and resistance to heated air of the section FI filters. Data collected during this testing consists of temperature, relative humidity, differential pressure, flow rate, upstream particle concentration, and downstream particle concentration. (authors)

A pump-free microfluidic 3D perfusion platform for the efficient differentiation of human hepatocyte-like cells.

Science.gov (United States)

Ong, Louis Jun Ye; Chong, Lor Huai; Jin, Lin; Singh, Pawan Kumar; Lee, Poh Seng; Yu, Hanry; Ananthanarayanan, Abhishek; Leo, Hwa Liang; Toh, Yi-Chin

2017-10-01

The practical application of microfluidic liver models for in vitro drug testing is partly hampered by their reliance on human primary hepatocytes, which are limited in number and have batch-to-batch variation. Human stem cell-derived hepatocytes offer an attractive alternative cell source, although their 3D differentiation and maturation in a microfluidic platform have not yet been demonstrated. We develop a pump-free microfluidic 3D perfusion platform to achieve long-term and efficient differentiation of human liver progenitor cells into hepatocyte-like cells (HLCs). The device contains a micropillar array to immobilize cells three-dimensionally in a central cell culture compartment flanked by two side perfusion channels. Constant pump-free medium perfusion is accomplished by controlling the differential heights of horizontally orientated inlet and outlet media reservoirs. Computational fluid dynamic simulation is used to estimate the hydrostatic pressure heads required to achieve different perfusion flow rates, which are experimentally validated by micro-particle image velocimetry, as well as viability and functional assessments in a primary rat hepatocyte model. We perform on-chip differentiation of HepaRG, a human bipotent progenitor cell, and discover that 3D microperfusion greatly enhances the hepatocyte differentiation efficiency over static 2D and 3D cultures. However, HepaRG progenitor cells are highly sensitive to the time-point at which microperfusion is applied. Isolated HepaRG cells that are primed as static 3D spheroids before being subjected to microperfusion yield a significantly higher proportion of HLCs (92%) than direct microperfusion of isolated HepaRG cells (62%). This platform potentially offers a simple and efficient means to develop highly functional microfluidic liver models incorporating human stem cell-derived HLCs. Biotechnol. Bioeng. 2017;114: 2360-2370. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Field-analysis of potable water quality and ozone efficiency in ozone-assisted biological filtration systems for surface water treatment.

Science.gov (United States)

Zanacic, Enisa; Stavrinides, John; McMartin, Dena W

2016-11-01

Potable water treatment in small communities is challenging due to a complexity of factors starting with generally poor raw water sources, a smaller tax and consumption base that limit capital and operating funds, and culminating in what is typically a less sophisticated and robust water treatment plant for production and delivery of safe, high quality potable water. The design and optimization of modular ozone-assisted biological filtration systems can address some of these challenges. In surface water treatment, the removal of organic matter (e.g., dissolved organic carbon - DOC), inorganic nutrients and other exposure-related contaminants (e.g., turbidity and dissolved solids) from the raw water source is essential. Thus, a combination of chemical and biological oxidation processes can produce an effective and efficient water treatment plant design that is also affordable and robust. To that end, the ozone-assisted biological filtration water treatment plants in two communities were evaluated to determine the efficacy of oxidation and contaminant removal processes. The results of testing for in-field system performance indicate that plant performance is particularly negatively impacted by high alkalinity, high organics loading, and turbidity. Both bicarbonate and carbonate alkalinity were observed to impede ozone contact and interaction with DOC, resulting in lower than anticipated DOC oxidation efficiency and bioavailability. The ozone dosage at both water treatment plants must be calculated on a more routine basis to better reflect both the raw water DOC concentration and presence of alkalinities to ensure maximized organics oxidation and minimization of trihalomethanes production. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Integrated bio-oxidation and adsorptive filtration reactor for removal of arsenic from wastewater.

Science.gov (United States)

Kamde, Kalyani; Dahake, Rashmi; Pandey, R A; Bansiwal, Amit

2018-01-08

Recently, removal of arsenic from different industrial effluent discharged using simple, efficient and low-cost technique has been widely considered. In this study, removal of arsenic (As) from real wastewater has been studied employing modified bio-oxidation followed by adsorptive filtration method in a novel continuous flow through the reactor. This method includes biological oxidation of ferrous to ferric ions by immobilized Acidothiobacillus ferrooxidans bacteria on granulated activated carbon (GAC) in fixed bed bio-column reactor with the adsorptive filtration unit. Removal efficiency was optimized regarding the initial flow rate of media and ferrous ions concentration. Synthetic wastewater sample having different heavy metal ions such as Arsenic (As), Cobalt (Co), Chromium (Cr), Copper (Cu), Iron (Fe), Lead (Pb) and Manganese (Mn) were also used in the study. The structural and surface changes occurring after the treatment process were scrutinized using FT-IR and Scanning Electron Microscopy (SEM) analysis. The finding showed that not only arsenic can be removed considerably in the bioreactor system, but also removing efficiency was much more (oxidation with adsorptive filtration method improves the removal efficiency of arsenic and other heavy metal ions in wastewater sample.

Simulations of Microbial-Enhanced Oil Recovery: Adsorption and Filtration

DEFF Research Database (Denmark)

Nielsen, Sidsel Marie; Nesterov, Igor; Shapiro, Alexander

2014-01-01

In the context of microbial-enhanced oil recovery (MEOR) with injection of surfactant-producing bacteria into the reservoir, different types of bacteria attachment and growth scenarios are studied using a 1D simulator. The irreversible bacteria attachment due to filtration similar to the deep bed...... applied to filtration model provides formation of two oil banks during recovery. This feature is not reproduced by application of REA model or DBF with growth in attached phase. This makes it possible to select a right model based on the qualitative analysis of the experimental data. A criterion...... is introduced to study the process efficiency: the dimensionless time at which average recovery between pure water injection and maximum surfactant effect is reached. This characteristic recovery period (CRP) was studied as a function of the different MEOR parameters such as bacterial activity, filtration...

Effect of humidity and particle hygroscopicity on the mass loading capacity of high efficiency particulate air (HEPA) filters

International Nuclear Information System (INIS)

Gupta, A.; Biswas, P.; Monson, P.R.; Novick, V.J.

1993-01-01

The effect of humidity, particle hygroscopicity, and size on the mass loading capacity of glass fiber high efficiency particulate air filters was studied. Above the deliquescent point, the pressure drop across the filter increased nonlinearly with areal loading density (mass collected/filtration area) of a NaCl aerosol, thus significantly reducing the mass loading capacity of the filter compared to dry hygroscopic or nonhygroscopic particle mass loadings. The specific cake resistance K 2 was computed for different test conditions and used as a measure of the mass loading capacity. K 2 was found to decrease with increasing humidity for nonhygroscopic aluminum oxide particles and for hygroscopic NaCl particles (at humidities below the deliquescent point). It is postulated that an increase in humidity leads to the formation of a more open particulate cake which lowers the pressure drop for a given mass loading. A formula for predicting K 2 for lognormally distributed aerosols (parameters obtained from impactor data) was derived. The resistance factor, R, calculated using this formula was compared to the theoretical R calculated using the Rudnick-Happel expression. For the nonhygroscopic aluminum oxide, the agreement was good but for the hygroscopic sodium chloride, due to large variation in the cake porosity estimates, the agreement was poor. 17 refs., 6 figs., 3 tabs

HEPA filter leaching concept validation trials at the Idaho Chemical Processing Plant

International Nuclear Information System (INIS)

Chakravartty, A.C.

1995-04-01

The enclosed report documents six New Waste Calcining Facility (NWCF) HEPA filter leaching trials conducted at the Idaho Chemical Processing Plant using a filter leaching system to validate the filter leaching treatment concept. The test results show that a modified filter leaching system will be able to successfully remove both hazardous and radiological constituents to RCRA disposal levels. Based on the success of the filter leach trials, the existing leaching system will be modified to provide a safe, simple, effective, and operationally flexible filter leaching system

Human HepaRG Cells can be Cultured in Hanging-drop Plates for Cytochrome P450 Induction and Function Assays.

Science.gov (United States)

Murayama, Norie; Usui, Takashi; Slawny, Nicky; Chesné, Christophe; Yamazaki, Hiroshi

2015-01-01

Recent guidance/guidelines for industry recommend that cytochrome P450 induction can be assessed using human hepatocyte enzyme activity and/or mRNA levels to evaluate potential drug- drug interactions. To evaluate time-dependent cytochrome P450 induction precisely, induction of CYP1A2, CYP2B6, and CYP3A4 mRNA was confirmed (>2-fold) by the treatment with omeprazole, phenobarbital, and rifampicin, respectively, for 24 or 48 h on day 3 from the start of culture. After 24 h, the fold induction of CYP1A2 with 3.6 and 1.8x10(4) HepaRG cells per well was lower than that for 7.2x10(4) cells. CYP1A2 induction levels at 24 h were higher than those after 48 h. In contrast, higher CYP2B6 inductions were confirmed after 48 h exposure than after 24 h, independent of the number of cells per well. To help reduce the use of human cryopreserved hepatocytes, typical P450-dependent enzyme activities were investigated in human HepaRG cells cultured in commercial hanging-drop plates. Newly designed 96-well hanging-drop plates were capable of maintaining human CYP3A-dependent midazolam hydroxylation activities for up to 4 days using only 10% of the recommended initial 7.2x10(4) cells per well. Favorable HepaRG function using hanging-drop plates was confirmed by detecting 1'- hydroxymidazolam O-glucuronide on day 3, suggesting an improvement over traditional control plates in which this metabolite can be detected for 24-well plates. These results suggest that the catalytic function and/or induction of CYP1A2, CYP2B6, and CYP3A4 can be readily assessed with reduced numbers of starting HepaRG cells cultured in three-dimensional cultures in drops prepared with hanging-drop plates.

Highway-runoff quality, and treatment efficiencies of a hydrodynamic-settling device and a stormwater-filtration device in Milwaukee, Wisconsin

Science.gov (United States)

Horwatich, Judy A.; Bannerman, Roger T.; Pearson, Robert

2011-01-01

The treatment efficiencies of two prefabricated stormwater-treatment devices were tested at a freeway site in a high-density urban part of Milwaukee, Wisconsin. One treatment device is categorized as a hydrodynamic-settling device (HSD), which removes pollutants by sedimentation and flotation. The other treatment device is categorized as a stormwater-filtration device (SFD), which removes pollutants by filtration and sedimentation. During runoff events, flow measurements were recorded and water-quality samples were collected at the inlet and outlet of each device. Efficiency-ratio and summation-of-load (SOL) calculations were used to estimate the treatment efficiency of each device. Event-mean concentrations and loads that were decreased by passing through the HSD include total suspended solids (TSS), suspended sediment (SS), total phosphorus (TP), total copper (TCu), and total zinc (TZn). The efficiency ratios for these constituents were 42, 57, 17, 33, and 23 percent, respectively. The SOL removal rates for these constituents were 25, 49, 10, 27, and 16 percent, respectively. Event-mean concentrations and loads that increased by passing through the HSD include chloride (Cl), total dissolved solids (TDS), and dissolved zinc (DZn). The efficiency ratios for these constituents were -347, -177, and 20 percent, respectively. Four constituents—dissolved phosphorus (DP), chemical oxygen demand (COD), total polycyclic aromatic hydrocarbon (PAH), and dissolved copper (DCu)—are not included in the list of computed efficiency ratio and SOL because the variability between sampled inlet and outlet pairs were not significantly different. Event-mean concentrations and loads that decreased by passing through the SFD include TSS, SS, TP, DCu, TCu, DZn, TZn, and COD. The efficiency ratios for these constituents were 59, 90, 40, 21, 66, 23, 66, and 18, respectively. The SOLs for these constituents were 50, 89, 37, 19, 60, 20, 65, and 21, respectively. Two constituents—DP and

Simulation of impaction filtration of aerosol droplets in porous media

OpenAIRE

Ghazaryan, L.; Lopez Penha, D.J.; Geurts, Bernardus J.; Stolz, S.; Stolz, Steffen; Winkelmann, Christoph; Pereira, J.C.F; Sequeira, A.; Pereira, J.M.C.

2010-01-01

We report on the development of a method to simulate from first principles the particle filtration efficiency of filters that are composed of structured porous media. We assume that the ratio of particle density to the fluid density is high. We concentrate on the motion of the particles in a laminar flow and quantify the role of inertial effects on the filtration of an ensemble of particles. We adopt the Euler-Lagrange approach, distinguishing a flow field in which the motion of a large numbe...

Volume reduction of contaminated filter wastes

International Nuclear Information System (INIS)

Buttedahl, O.I.; Terada, K.

1976-01-01

Reported are details of a pilot project to design and construct a compactor to reduce the handling of high efficiency particulate air (HEPA) filters used in air filtration systems at facilities where radioactive materials are processed. In such systems at Rocky Flats Plant, filters require frequent change and removal. Large quantities are used and will be increased for future operations. With the completion of the pilot model, it has been demonstrated that volume reductions of more than 80% can be achieved and cost savings will be realized also

Evaluation of Impact of Coagulant Type on Operation Parameters in Direct Filtration

Directory of Open Access Journals (Sweden)

Ali Torabian

2007-06-01

Full Text Available Numerous advantages have been reported on PAC (poly aluminum chloride used as a coagulant over other coagulants such as alum and ferric chloride used in conventional water treatment process with medium and high turbidity levels. These include lower amounts of PACL required specially in removing turbidity, larger floc grain formation, reduced floc sedimentation time, lower sludge production, and relaxation of the need for pH adjustment by lime, among others. The present study aims to evaluate the effects of different coagulants such as ferric chloride and PACL on direct filtration and to identify the most effective material based on both turbidity and particle removal efficiencies. A perfectly experimental pilot system, including raw water preparation, coagulation, flocculation, distribution measurement, and filtration units, was designed and used. Raw water turbidity level in the experimental pilot was below 10 NTU. The effects of various parameters such as coagulant type, filtration rate, and coagulant dosage on the performance of the filter were investigated. The results obtained from several filtration cycles under different conditions indicated that average effluent turbidity level, effluent particle numbers, effluent turbidity variation graph, and effluent particle graph were lower throughout the filtration cycle when PACL was used compared to when ferric chloride was used as the coagulant. Increasing filtration rate led to increased turbidity and particle number. Addition of 2 mg/l of PACL (poor coagulation and flocculation scenario was compared with addition of 5 mg/l of ferric chloride (strong coagulation and flocculation scenario. The results indicated that higher average values of turbidity removal but lower turbidity and particle removal efficiencies obtained in the case of the poor coagulation and flocculation scenario.

High efficiency filtration of liquid-metal-generated aerosols

International Nuclear Information System (INIS)

First, M.W.

1977-01-01

This paper will present data on filter performance for the range of sodium-containing aerorols that can result from large and small releases of hot metallic sodium into confined spaces containing air or special atmospheres and will compare the particle collection effectiveness, space and power requirements, service life, and disposal of the collected materials for the several options. Prompt reduction of in-vessel aerosols with methods that induce rapid coagulation and sedimentation by the application of violent turbulance, sonic energy, or electrostatic attraction; by aerosol scavenging with massive inert dust additions; and by a number of other innovative methods is of special interest because of their potential ability to bring down the aerosol cloud very rapidly and thereby to reduce vessel out-leakage drastically; as well as to relieve the particle load on filters. These methods will be examined as supplements to filtration methods for control of sodium-containing aerosols

In Vivo Evaluation of a New Embolic Spherical Particle (HepaSphere) in a Kidney Animal Model

International Nuclear Information System (INIS)

Luis, Esther de; Bilbao, Jose I.; Ciercoles, Jose A. Garcia Jalon de; Martinez-Cuesta, Antonio; Martino Rodriguez, Alba de; Lozano, Maria D.

2008-01-01

HepaSphere is a new spherical embolic material developed in a dry state that absorbs fluids and adapts to the vessel wall, leaving no space between the particle and the arterial wall. The aim of this study was to elucidate the final in vivo size, deformation, final location, and main properties of the particles when reconstituted with two different contrast media (Iodixanol and Ioxaglate) in an animal model. Two sizes of 'dry-state' particles (50-100 and 150-200 μm) were reconstituted using both ionic and nonionic contrast media. The mixture was used to partly embolize both kidneys in an animal model (14 pigs). The animals were sacrificed 4 weeks after the procedure and the samples processed. The final size of the particles was 230.2 ± 62.5 μm for the 50- to 100-μm dry-state particles and 314.4 ± 71 μm for the 150- to 200-μm dry-state particles. When the contrast medium (ionic versus nonionic) used for the reconstitution was studied to compare (Student's t-test) the final size of the particles, no differences were found (p > 0.05). The mean in vivo deformation for HepaSphere was 17.1% ± 12.3%. No differences (p > 0.05) were found in the deformation of the particle regarding the dry-state size or the contrast medium (Mann-Whitney test). We conclude that HepaSphere is stable, occludes perfectly, and morphologically adapts to the vessel lumen of the arteries embolized. There is no recanalization of the arteries 4 weeks after embolization. Its final in vivo size is predictable and the particle has the same properties in terms of size and deformation with the two different contrast media (Iodixanol and Ioxaglate)

High-Temperature Particulate Matter Filtration with Resilient Yttria-Stabilized ZrO2 Nanofiber Sponge.

Science.gov (United States)

Wang, Haolun; Lin, Sen; Yang, Shen; Yang, Xudong; Song, Jianan; Wang, Dong; Wang, Haiyang; Liu, Zhenglian; Li, Bo; Fang, Minghao; Wang, Ning; Wu, Hui

2018-05-01

Particulate matter (PM) is a major air pollutant in many regions, jeopardizing ecosystems and public health. Filtration at pollutant source is one of the most important ways to protect the environment, however, considering the high-temperature exhaust gas emissions, effective removal of PM and related pollutants from their sources remains a major challenge. In this study, a resilient, heat-resisting, and high-efficiency PM filter based on yttria-stabilized ZrO 2 (YSZ) nanofiber sponge produced with a scalable solution blow spinning process is reported. The porous 3D sponge composed of YSZ nanofibers is lightweight (density of 20 mg cm -3 ) and resilient at both room temperature and high temperatures. At room-temperature conditions, the YSZ nanofiber sponge exhibits 99.4% filtration efficiency for aerosol particles with size in the range of 20-600 nm, associated with a low pressure drop of only 57 Pa under an airflow velocity of 4.8 cm s -1 . At a high temperature of 750 °C, the ceramic sponge maintains a high filtration efficiency of 99.97% for PM 0.3-2.5 under a high airflow velocity of 10 cm s -1 . A practical vehicle exhaust filter to capture particles with filtration efficiency of >98.3% is also assembled. Hence, the YSZ nanofiber sponge has enormous potential to be applied in industry. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Studies on soy protein isolate/polyvinyl alcohol hybrid nanofiber membranes as multi-functional eco-friendly filtration materials

International Nuclear Information System (INIS)

Fang, Qun; Zhu, Ming; Yu, Siruo; Sui, Gang; Yang, Xiaoping

2016-01-01

Highlights: • Biodegradable filtration membranes were prepared. • Polar groups in the membrane surface helped capture fine particles. • Loading filtration efficiency can reach 99.99% in the case of small pressure drop. • Filtration membrane showed antimicrobial activity to Escherichia coli. - Abstract: A biodegradable and multifunctional air filtration membrane was prepared by electrospinning of soy protein isolate (SPI)/polyvinyl alcohol (PVA) system in this paper. The optimized SPI/PVA proportion in the spinning solution was determined according to the analyses of microstructure, surface chemical characteristic and mechanical property of the hybrid nanofiber membranes. Under the preferred preparation condition, two kinds of polymer materials displayed a good compatibility in the hybrid nanofibers, and a large number of polar groups existed in the membrane surface. The loading filtration efficiency of the nanofiber membrane with optimal material ratio and areal density can reach 99.99% after test of 30 min for fine particles smaller than 2.5 μm in the case of small pressure drop. Besides, this kind of filtration membrane showed an antimicrobial activity to Escherichia coli in the study. The SPI/PVA hybrid nanofiber membrane with proper material composition and microstructure can be used as a new type of high performance eco-friendly filtration materials.

Studies on soy protein isolate/polyvinyl alcohol hybrid nanofiber membranes as multi-functional eco-friendly filtration materials

Energy Technology Data Exchange (ETDEWEB)

Fang, Qun; Zhu, Ming; Yu, Siruo; Sui, Gang, E-mail: suigang@mail.buct.edu.cn; Yang, Xiaoping

2016-12-15

Highlights: • Biodegradable filtration membranes were prepared. • Polar groups in the membrane surface helped capture fine particles. • Loading filtration efficiency can reach 99.99% in the case of small pressure drop. • Filtration membrane showed antimicrobial activity to Escherichia coli. - Abstract: A biodegradable and multifunctional air filtration membrane was prepared by electrospinning of soy protein isolate (SPI)/polyvinyl alcohol (PVA) system in this paper. The optimized SPI/PVA proportion in the spinning solution was determined according to the analyses of microstructure, surface chemical characteristic and mechanical property of the hybrid nanofiber membranes. Under the preferred preparation condition, two kinds of polymer materials displayed a good compatibility in the hybrid nanofibers, and a large number of polar groups existed in the membrane surface. The loading filtration efficiency of the nanofiber membrane with optimal material ratio and areal density can reach 99.99% after test of 30 min for fine particles smaller than 2.5 μm in the case of small pressure drop. Besides, this kind of filtration membrane showed an antimicrobial activity to Escherichia coli in the study. The SPI/PVA hybrid nanofiber membrane with proper material composition and microstructure can be used as a new type of high performance eco-friendly filtration materials.

The Use of Innovative Ceramic-Carbon Bonded Filters Used for Filtration of Liquid Alloys and Evaluation of the Filtration Efficiency

Directory of Open Access Journals (Sweden)

Karwiński A.

2014-08-01

Full Text Available Extremely intense development of civilization requires from foundry casting technologies very high quality and not expensive castings. In the foundries, there are many treatments that allow increasing of the final properties of produced castings such as refining, modification, heat treatment, etc. One of the methods of increasing the quality of the casting by removing inclusions from the liquid alloy is filtration. The use of ceramic-carbon foam filters in filtration process is still analysed phenomenon that allows improving the final properties of castings. A modern method of research, testing and synthesis of innovative chemical compositions allows improving the properties of such filters. In the paper the evaluation of application properties of developed ceramic-carbon bonded foam filters is presented. The quality of the foam filters is evaluated by Computer Tomography and foundry trials in pouring of liquid metal in test molds. Additionally computer simulations were made to visualize the flow characteristics in the foam filter. The analysed filters are the result of the research work of Foundry Research Institute and the Institute of Ceramics and Building Materials, Refractory Materials Department in Gliwice.

Experiences in radioactive gaseous effluent management in JAERI

International Nuclear Information System (INIS)

Yoshida, Y.; Matsui, H.; Yamamoto, H.; Ikezawa, Y.; Hirayama, K.; Kokubu, M.

1983-01-01

In the Japan Research Reactor-II (JRR-2), the main source of 41 Ar generation is the exhaust air from the horizontal experimental holes and the pneumatic tubes. For the horizontal experimental holes, the flow of exhaust air through the holes was decreased by improving the airtightness, and a decay duct of capacity 2.4 m 3 was installed in the middle of the exhaust line. In consequence, the release rate of 41 Ar was reduced by 6-8%. For the pneumatic tubes, a mechanical shutter was installed in the tube. The shutter stops the exhaust air flow, except when the pneumatic tube is used. Prior to the use, the activated air in the tube is led to a decay tank. As a result, the 41 Ar release rate was reduced by 10-20%. By the above means, the yearly exposure at the site boundary was reduced to 0.36 mR from 2.6 mR. In Hot Laboratory for metallurgical examination of spent fuel, the exhaust filtration system consists of filters in the cave, i.e. frame trap, prefilter, HEPA filter, and the main filter system, i.e. prefilter, two-stage HEPA filter and charcoal filter (the charcoal filter is by-passed to lengthen its life when radioiodine is not released). Values of removal efficiency and the dispersion factor for iodine were 80% and 4.4x10 - 3 and for cesium 97% and 3.5x10 - 3 , respectively. The exhaust filtration system in Radioactive Waste Incineration Plant consists of a two-stage ceramic filter installed immediately after the incinerator, air cooler, two-stage HEPA filter and final scrubber. The decontamination factor of the two-stage ceramic filter is 1x10 6 for particulate matter, when measured with radioactive particles from burning of simulated contaminants with 75 mCi of 137 Cs. The decontamination factor of the HEPA filter after the ceramic filter is about 10 3 . The overall decontamination factor for the plant is estimated to be more than 10 6

Novel Particulate Air-Filtration Media: Market Survey

Science.gov (United States)

2013-02-01

larger and more efficient filter designs similar to those being considered for future integrated respirator/helmet systems. To avoid eliminating ...including nonwoven, woven, and electret and combinations of media. Some of the manufacturers identified themselves as specializing in biofiltration or...Three Millipore products were identified. The 0.2 µm hydrophobic Aervent PTFE membrane62 is used for the sterile filtration of gases . Aerex

Filtration behaviors of rod-shaped bacterial broths in unsteady-state phase of cross-flow filtration

Energy Technology Data Exchange (ETDEWEB)

Tanaka, T.; Usui, K.; Koda, K.; Nakanishi, K. [Okayama University, Okayama (Japan). Faculty of Engineering

1996-12-20

Filtration behaviors in the unsteady-state phase of crossflow filtration of broths of Bacillus subtilis, Escherichia coli, and Lactobacillus delbrueckii, which are rod-shaped, were studied from the viewpoint of the changes in the specific resistance and in the structure of the microbial cake formed on the membrane surface. The permeation flux followed the cake filtration law at the initial stage of the crossflow filtration of the broths of B. subtilis and E. coli, where the cells deposited randomly on the membrane. In the case of the crossflow filtration of a L. delbrueckii broth, the period of random deposition was shorter. The specific resistance for the cake formed at the initial stage agreed with that measured in dead-end filtration. Then, the specific resistance started to increase in comparison with that measured in dead-end filtration due to shear-induced arrangement of the cells. The extent of the increase in specific resistance became higher and the time taken to start the cell arrangement became shorter with increasing circulation flow rate. The increase in specific resistance due to the shear-induced arrangement was more appreciable in the crossflow filtration of the broth of L. delbrueckii than that of B. subtilis and E. coli. The average permeation flux was increased considerably by applying periodical backwashing with appropriate time intervals. The permeation flux was well predicted by the cake filtration law, since the cells deposited in a way similar to that for dead-end filtration during a sufficiently short period of crossflow filtration in a backwashing mode. 21 refs., 11 figs.

Feasibility study of micro-filtration for algae separation in an innovative nuclear effluents decontamination process

International Nuclear Information System (INIS)

Gouvion Saint Cyr, D. de; Wisniewski, C.; Schrive, L.; Farhi, E.; Rivasseau, C.

2014-01-01

Bio-remediation technologies often offer efficiency, cost and environmental impact benefits against physico-chemical technologies. Concerning the remediation of radionuclide-containing water, a few bio-based technologies have been proposed but none is currently operational in highly radioactive environments. A new radio-tolerant micro-alga, isolated from a nuclear facility, possesses properties that offer new decontamination prospects for the nuclear industry or for the clean-up of environmental water. A pilot-scale treatment unit based on this alga is currently under development for the decontamination of radioactive water. It includes separation and/or concentration steps relying on membrane filtration. This work aims at verifying the feasibility of micro-filtration as separation step for the targeted algae separation. Recommendations about the choice of operating conditions limiting and/or controlling the membrane fouling are provided with the objective to enhance the separation efficiency. Lab-scale dead-end filtration tests were implemented and the key factors involved in the separation performances were investigated. Membrane characteristics, biomass composition, and hydrodynamic conditions were considered. Organic membranes provided adequate filtration performance. Membrane fouling was essentially induced by a rapid reversible algae deposit and to a lesser extent by irreversible pore blockage caused by smaller particles and dissolved organic matter. To cancel the reversible fouling, hydrodynamic actions such as stirring and back-flush efficiently prevented algae deposit, allowing higher filtration productivity. This study demonstrates the feasibility of membrane separation for micro-algae harvesting at laboratory-scale and specifies the suitable working conditions. (authors)

Filtration behavior of silver nanoparticle agglomerates and effects of the agglomerate model in data analysis

International Nuclear Information System (INIS)

Buha, Jelena; Fissan, Heinz; Wang, Jing

2013-01-01

In many data evaluation procedures for particle measuring devices and in filtration models, spherical particles are assumed. However, significant fractions of aerosol particles are agglomerates of small primary spheres. The morphology of particles in filtration processes may not be known a priori and if the filtration data are processed with wrong assumption, errors can be induced. In this work, we have quantified such errors for the case of open-structured agglomerates. Filtration efficiency tests with polydisperse silver nanoparticle agglomerates and their sintered spheres were performed. After the sintering process, particles with a compact structure with the shape close to a sphere are obtained, which are referred to as sintered spheres in the present study. The testing method involved generation of particulate forms, passing the particles through the testing section, and measurement of the particle number concentrations and size distributions before and after the filter. Measurements of the aerosols upstream and downstream of the filter were conducted using scanning mobility particle sizers (SMPS, TSI Inc.), which covered the rage from 10 to 480 nm. Particles were additionally characterized from the electron microscopic images and the average primary particle size was determined to be 16.8 nm. The number-size distribution curves were obtained and used for penetration calculation. The penetration was dependent on the particle size and morphology. Silver-sintered spheres were captured with a lower efficiency than agglomerates with the same mobility diameter because of the stronger interception effect for agglomerates. Data analysis of the number-size distribution for agglomerates was processed based on sphere assumption and using the model for open-structured agglomerates developed by Lall and Friedlander. The efficiencies based on total concentrations of number, surface and volume were affected when the agglomerate model was used. The effect was weakest for the

Remote operated vehicle with carbon dioxide blasting (ROVCO{sub 2})

Energy Technology Data Exchange (ETDEWEB)

Resnick, A.M. [Oceaneering International, Inc., Upper Marlboro, MD (United States)

1995-10-01

The Remote Operated Vehicle with Carbon Dioxide Blasting (ROVCO{sub 2}), as shown in a front view is a six-wheeled remote land vehicle used to decontaminate concrete floors. The remote vehicle has a high pressure Cryogenesis blasting subsystem, Oceaneering Technologies (OTECH) developed a CO{sub 2} xY Orthogonal Translational End Effector (COYOTEE) subsystem, and a vacuum/filtration and containment subsystem. The cryogenesis subsystem performs the actual decontamination work and consists of the dry ice supply unit, the blasting nozzle, the remotely controlled electric and pneumatic valves, and the vacuum work-head. The COYOTEE subsystem positions the blasting work-head within a planar work space and the vacuum subsystem provides filtration and containment of the debris generated by the CO{sub 2} blasting. It employs a High Efficiency Particulate Air (HEPA) filtration unit to separate contaminants for disposal. All of the above systems are attached to the vehicle subsystem via the support structure.

Filtration and compression of organic materials

DEFF Research Database (Denmark)

Christensen, Morten Lykkegaard; Keiding, Kristian

is to use more simple systems. Dextran-MnO2 particles and polystyrene particles with a water-swollen polyacrylic acid shell have therefore been synthesised. These particles have been filtered and used to study the non-linear filtration behaviour. The compressibility of the formed cake has been investigated......The conventional filtration theory has been based on filtrations of incompressible particles such as anatase, kaolin and clay. The filtration models have later been used for organic slurries but can often not explain the observed experimental data. At constant pressure, the filtrate volume does...... and the discrepancy between the filtration theory and the observed filtration behaviour explained as a time-dependent collapse of the formed cake (creep). Thus, the creep phenomenon has been adopted in the conventional filtration models and it will be shown that the model can be used to simulate filtration data...

Influence of Low-Temperature Plasma Treatment on The Liquid Filtration Efficiency of Melt-Blown PP Nonwovens in The Conditions of Simulated Use of Respiratory Protective Equipment

Directory of Open Access Journals (Sweden)

Majchrzycka Katarzyna

2017-06-01

Full Text Available Filtering nonwovens produced with melt-blown technology are one of the most basic materials used in the construction of respiratory protective equipment (RPE against harmful aerosols, including bio- and nanoaerosols. The improvement of their filtering properties can be achieved by the development of quasi-permanent electric charge on the fibres. Usually corona discharge method is utilized for this purpose. In the presented study, it was assumed that the low-temperature plasma treatment could be applied as an alternative method for the manufacturing of conventional electret nonwovens for the RPE construction. Low temperature plasma treatment of polypropylene nonwovens was carried out with various process gases (argon, nitrogen, oxygen or air in a wide range of process parameters (gas flow velocity, time of treatment and power supplied to the reactor electrodes. After the modification, nonwovens were evaluated in terms of filtration efficiency of paraffin oil mist. The stability of the modification results was tested after 12 months of storage and after conditioning at elevated temperature and relative humidity conditions. Moreover, scanning electron microscopy and ATR-IR spectroscopy were used to assess changes in surface topography and chemical composition of the fibres. The modification of melt-blown nonwovens with nitrogen, oxygen and air plasma did not result in a satisfactory improvement of the filtration efficiency. In case of argon plasma treatment, up to 82% increase of filtration efficiency of paraffin oil mist was observed in relation to untreated samples. This effect was stable after 12 months of storage in normal conditions and after thermal conditioning in (70 ± 3°C for 24 h. The use of low-temperature plasma treatment was proven to be a promising improvement direction of filtering properties of nonwovens used for the protection of respiratory tract against harmful aerosols.

Silica incorporated membrane for wastewater based filtration

Science.gov (United States)

Fernandes, C. S.; Bilad, M. R.; Nordin, N. A. H. M.

2017-10-01

Membrane technology has long been applied for waste water treatment industries due to its numerous advantages compared to other conventional processes. However, the biggest challenge in pressure driven membrane process is membrane fouling. Fouling decreases the productivity and efficiency of the filtration, reduces the lifespan of the membrane and reduces the overall efficiency of water treatment processes. In this study, a novel membrane material is developed for water filtration. The developed membrane incorporates silica nanoparticles mainly to improve its structural properties. Membranes with different loadings of silica nanoparticles were applied in this study. The result shows an increase in clean water permeability and filterability of the membrane for treating activated sludge, microalgae solution, secondary effluent and raw sewage as feed. Adding silica into the membrane matrix does not significantly alter contact angle and membrane pore size. We believe that silica acts as an effective pore forming agent that increases the number of pores without significantly altering the pore sizes. A higher number of small pores on the surface of the membrane could reduce membrane fouling because of a low specific loading imposed to individual pores.

Comparison of Emery 3004 and 3006 characteristics with DOP for possible use in HEPA filter leak tests

Energy Technology Data Exchange (ETDEWEB)

Kovach, B.J.; Banks, E.M.; Kovacs, G. [Nuclear Consulting Services, Inc., Columbus, OH (United States)

1995-02-01

The particle size distribution, concentration, liquid to aerosol conversion rate and ignition properties of DOP, Emery 3004 and Emery 3006 aerosols generated by the NUCON Aerosol Generators Models SN-10 and DG-F were obtained. Results demonstrate the Emery products are acceptable replacements for DOP in performing leak testing of HEPA filters.

Filtration in Porous Media

DEFF Research Database (Denmark)

Yuan, Hao; Shapiro, Alexander

There is a considerable and ongoing effort aimed at understanding the transport and the deposition of suspended particles in porous media, especially non-Fickian transport and non-exponential deposition of particles. In this work, the influential parameters in filtration models are studied...... to understand their effects on the non-Fickian transport and the non-exponential deposition. The filtration models are validated by the comparisons between the modelling results and the experimental data.The elliptic equation with distributed filtration coefficients may be applied to model non-Fickian transport...... and hyperexponential deposition. The filtration model accounting for the migration of surface associated particles may be applied for non-monotonic deposition....

Granular filtration for airborne particles : correlation between experiments and models

Energy Technology Data Exchange (ETDEWEB)

Golshahi, L.; Tan, Z. [Calgary Univ., AB (Canada). Schulich School of Engineering, Mechanical and Manufacturing Dept.; Abedi, J. [Calgary Univ., AB (Canada). Schulich School of Engineering, Chemical and Petroleum Engineering Dept.

2009-10-15

A new design for a packed bed granular filter was presented. The cylindrical packed bed was designed to filter particles in the range of approximately 10 nm to 15 {mu}m in diameter in different kinetic conditions and configurations. The aim of the study was to develop a precise empirical model to predict the filtration efficiency of the packed beds. A collision-type atomizer was used to generate polydisperse sodium chloride aerosol particles. The effect of flow rates was studied using a thermal mass flow meter. A regression analysis technique was used to determine the correlation between single granule and total packed bed efficiency for the entire granular filter. The experimental data were then compared with results obtained from the theoretical analysis. The least square method was used to correlate experimental data and to develop generalized equations for single granule efficiency. The study showed that the granular filter media has a high filtration efficiency for both micron and submicron particles. It was concluded that the effect of media thickness was more significant at higher flow rates than at lower flow rates. 10 refs., 3 figs.

High temperature filtration of radioactivable corrosion products in the primary circuit of PWR type reactors

International Nuclear Information System (INIS)

Dolle, L.

1976-01-01

A effective limitation to the deposition of radioactive corrosion products in the core of a reactor at power operation, is to be obtained by filtering the water of the primary circuit at a flow rate upper than 1% of the coolant flow rate. However, in view of accounting for more important release of corrosion products during the reactor start-up and also for some possible variations in the efficiency of the system, it is better that the flow rate to be treated by the cleaning circuit is stated at 5%. Filtration must be effected at the temperature of the primary circuit and preferably on each loop. To this end, the feasibility of electromagnetic filtration or filtration through a deep bed of granulated graphite has been studied. The on-loop tests effected on each filter gave efficiencies and yields respectively upper than 90% and 99% for magnetite and ferrite particles in suspension in water at 250 deg C. Such results confirm the interest lying in high temperature filtration and lead to envisage its application to reactors [fr

Filtration of Oil-furnace Carbon Black Dust Particles from the Tail Gases by Filter Bags With PTFE Membrane

Directory of Open Access Journals (Sweden)

Čuzela, D.

2010-01-01

Full Text Available During the industrial production of oil furnace carbon black, tail gases containing oil-furnace carbon black dust particles are emitted to the atmosphere. In the carbon black plant, Petrokemija d. d., there are six exhaust stacks for tail gases. Each of them has installed process equipment for cleaning tail gases. Efficiency of cleaning mainly depends on equipment construction and cleaning technology. The vicinity of the town, quality of the air in the region of Kutina, regarding floating particles PM10, and corporate responsibility for further enviromental improvement, imposes development of new methods that will decrease the emmision of oil-furnace carbon black dust particles in the air. Combining centrifugal percipitator and filter, special construction of cyclofilter for filtration of oil-furnace carbon black dust particles from tail gases by using PTFE (polytetrafluoroethylene membrane filter bags, was designed. Developed filtration technique provides η = 99.9 % efficiency of filtration. Construction part of the filter contains the newest generation of PTFE membrane filter bags with the ability of jet pulse cleaning. Using the PTFE membrane filter bags technology, filtration efficiency for oil-furnace carbon black dust particles in tail gases of maximum γ=5mgm-3can be achieved. The filtration efficiency was monitored continuously measuring the concentration of the oil-furnace carbon black dust particles in the tail gases with the help of in situ electronic probe. The accomplished filtration technology is the base for the installation of the PTFE membrane filter bags in the main operation filters which will provide better protection of the air in the town of Kutina against floating particles PM10.

Advanced Filter Technology For Nuclear Thermal Propulsion

Science.gov (United States)

Castillon, Erick

2015-01-01

The Scrubber System focuses on using HEPA filters and carbon filtration to purify the exhaust of a Nuclear Thermal Propulsion engine of its aerosols and radioactive particles; however, new technology may lend itself to alternate filtration options, which may lead to reduction in cost while at the same time have the same filtering, if not greater, filtering capabilities, as its predecessors. Extensive research on various types of filtration methods was conducted with only four showing real promise: ionization, cyclonic separation, classic filtration, and host molecules. With the four methods defined, more research was needed to find the devices suitable for each method. Each filtration option was matched with a device: cyclonic separators for the method of the same name, electrostatic separators for ionization, HEGA filters, and carcerands for the host molecule method. Through many hours of research, the best alternative for aerosol filtration was determined to be the electrostatic precipitator because of its high durability against flow rate and its ability to cleanse up to 99.99% of contaminants as small as 0.001 micron. Carcerands, which are the only alternative to filtering radioactive particles, were found to be non-existent commercially because of their status as a "work in progress" at research institutions. Nevertheless, the conclusions after the research were that HEPA filters is recommended as the best option for filtering aerosols and carbon filtration is best for filtering radioactive particles.

Dose- and time-dependent effects of phenobarbital on gene expression profiling in human hepatoma HepaRG cells

International Nuclear Information System (INIS)

Lambert, Carine B.; Spire, Catherine; Claude, Nancy; Guillouzo, Andre

2009-01-01

Phenobarbital (PB) induces or represses a wide spectrum of genes in rodent liver. Much less is known about its effects in human liver. We used pangenomic cDNA microarrays to analyze concentration- and time-dependent gene expression profile changes induced by PB in the well-differentiated human HepaRG cell line. Changes in gene expression profiles clustered at specific concentration ranges and treatment times. The number of correctly annotated genes significantly modulated by at least three different PB concentration ranges (spanning 0.5 to 3.2 mM) at 20 h exposure amounted to 77 and 128 genes (p ≤ 0.01) at 2- and 1.8-fold filter changes, respectively. At low concentrations (0.5 and 1 mM), PB-responsive genes included the well-recognized CAR- and PXR-dependent responsive cytochromes P450 (CYP2B6, CYP3A4), sulfotransferase 2A1 and plasma transporters (ABCB1, ABCC2), as well as a number of genes critically involved in various metabolic pathways, including lipid (CYP4A11, CYP4F3), vitamin D (CYP24A1) and bile (CYP7A1 and CYP8B1) metabolism. At concentrations of 3.2 mM or higher after 20 h, and especially 48 h, increased cytotoxic effects were associated with disregulation of numerous genes related to oxidative stress, DNA repair and apoptosis. Primary human hepatocyte cultures were also exposed to 1 and 3.2 mM PB for 20 h and the changes were comparable to those found in HepaRG cells treated under the same conditions. Taken altogether, our data provide further evidence that HepaRG cells closely resemble primary human hepatocytes and provide new information on the effects of PB in human liver. These data also emphasize the importance of investigating dose- and time-dependent effects of chemicals when using toxicogenomic approaches

Liquid aerosol filtration by fibrous filters in interception and inertial regimes; Filtration des aerosols liquides par les filtres a fibres en regimes d`interception et d`inertie

Energy Technology Data Exchange (ETDEWEB)

Gougeon, R

1994-09-26

In most previous studies of aerosol filtration, attention is focused on the maximum penetrating particle size region where the predominant mechanisms for collection are brownian diffusion and interception. In contrary the inertial regime remains poorly understood. Therefore, the aim of this study was to improve understanding of the behaviour of fibrous filters with liquid aerosols ar high frontal velocities both in the stationary and nonstationary filtration. Stationary filtration is first investigated. Experiments are done with special filters called `formettes` which have well defined structural characteristics. Precise results obtained with those filters allow us to select two relations quoted in the literature in order to describe the diffusion and the interception and to determine an empirical correlation describing the inertial impaction. Then this correlation with an industrial filter. In the second part, the evolution of the performances of fibrous filters loaded with liquid aerosols is studied experimentally and theoretically. We show that, in the inertial regime the filter efficiency first decreases and then increases rapidly with the loading rate. This increase is particularly important at high frontal velocities and with big particles. Macroscopic observations of high loaded filters show that the liquid is located in the fibre`s intersections to form big flat surfaces. A tentative of describing the evolution of the filter efficiency in modifying our stationary filtration model in order to take into account those liquid surfaces in the filter gives encouraging results. (authors). 92 refs., 93 figs., 11 tabs., 4 appends.

Non-stationary open-flow filtration of ground waters at the Pripyat'-Dnieper inter river

International Nuclear Information System (INIS)

Tarapon, A.G.

1989-01-01

Consideration is given to filtration of ground waters into rivers and to effect of drainage devices. Investigations were conducted with use of modelling of planned and profile filtration of ground waters at the electric models. Efficiency of engineering protection facilities suggested, was studied to prevent contamination of water intakes. Modelling shown, that contamination washing out process was in a cycle character with 1 year period. Use of drainage canal with the water level 0.8 m lower than in the river, is an effective way to prevent filtration of ground waters into the Pripyat' and the Dnieper from the upper open-flow aquiver

Hot filtration 2

International Nuclear Information System (INIS)

Jimenez Rebagliati, Raul; Liberman, S.J.

1982-01-01

The magnetic filtration technique allows the removal of suspended magnetic species from a fluid at high flow rate and temperature. It is specially advantageous for water purification in systems such as thermonuclear and thermoelectric plants in which corrosion products must be removed from the heat transport and cooling circuits. Using diluted aqueous suspensions of magnetite, the behaviour of a ball matrix filter was studied as a function of flow rate, temperature and concentration of particles. The retention efficiency shows an exponential decay with fluid's velocity and viscosity in agreement with theory. Within the range of concentration considered, there is no change in the retention with concentration. Design parameters for filters according to plant's needs are obtained from the results of this study. (Author) [es

Corrosion-product filtration in PWRs: Topical report

International Nuclear Information System (INIS)

Balakrishnan, P.V.; Buckley, L.P.

1988-04-01

As part of a programme on the optimization of pressurized water reactor (PWR) secondary side water treatment, laboratory-scale studies on filtration of the feedwater using materials having chemically active adsorbing surfaces were carried out. Graphite, zirconia and titania were identified, from a review of existing literature, as suitable filtration media, the last two because of their ion-exchange capability. The efficiency of filters packed with granular graphite for filtration of simulated feed train corrosion products and the pressure drop across the filters were determined as functions of filter dimensions and operating parameters at room temperature. A rough sizing of a full-flow feedwater filter using granular graphite was done on the basis of observations from the room temperature tests. Further studies are suggested at low concentrations of the corrosion product and at high temperature typical of steam generator feedwater after the high pressure heaters to derive realistic design parameters for a filter for installation in the PWR secondary circuit. Zirconia was produced in the form of spherical particles using a sol-gel process. The zirconia behaved as an anion exchanger at low pH and as a cation exchanger at high pH. Its suitability for purification of water at high temperature should be determined by futher studies. 30 refs., 16 figs., 8 tabs

PROBLEMS OF NONSTATIONARY FILTRATION

Directory of Open Access Journals (Sweden)

Vsevolod A. Shabanov

2018-03-01

Full Text Available he article deals with the classical hydrodynamic theory of filtration. Discusses models of soil, fluid and nature of fluid flow that formed the basis for the creation of the classic filtration theory. Also discusses the assumptions made for the linearization of the equations. Evaluated the scope of the classical filtration theory. Proposed a new model of filtration through a porous medium, based on the application of the laws of theoretical mechanics. It is based on the classical model of soil: the soil is composed of capillaries with ..parallel axes, in which the liquid moves. For tasks of infiltration equations of motion. Considered special cases of unsteady motion of a finite volume of liquid. Numerical example a machine experiment.

Aerosol filtration with metallic fibrous filters

International Nuclear Information System (INIS)

Klein, M.; Goossens, W.R.A.

1983-01-01

The filtration efficiency of stainless steel fibrous filters (BEKIPOR porous mats and sintered webs) is determined using submicronic monodisperse polystyrene aerosols. Lasers spectrometers are used for the aerosol measurements. The parameters varied are the fiber diameter, the number of layers, the aerosol diameter and the superficial velocity. Two selected types of filters are tested with polydisperse methylene blue aerosols to determine the effect of bed loading on the filter performance and to test washing techniques for the regeneration of the filter

Organo-clay/anthracite filtration for oil removal

International Nuclear Information System (INIS)

Moazed, H.; Viragahavan, T.

1999-01-01

An advantage of organo-clay compared to other sorbents is that it can selectively remove organic pollutants from contaminated waters. An investigation was conducted to determine the potential of an organo-clay/anthracite mixture as a filter media for the removal of oil from synthetic and real oily waters. Also included in the study were column filtration studies using synthetic and real waste waters to determine the sorptive capacity of the material. In general, oil removal efficiencies in a 300 mm organo-clay/anthracite bed decreased with an increase in flow rates. Results of eight hour studies indicated that the depth of an organo-clay/anthracite bed has a direct effect on oil removal efficiency. The Thomas equation provides a reasonable fit of the data based on breakthrough studies. The model can be used to determine the parameters needed to design full-scale filtration columns. The uptake of oil by an organo-clay/anthracite mixture is well described by an equation including time such as the Weber or Moris model. The maximum solid-phase concentration of the solute values obtained from the Thomas equation were comparable to the values found by a mass balance approach. 12 refs., 8 figs., 4 tabs

Experiment on a multilayer type air filter for the filtration of sodium aerosol

International Nuclear Information System (INIS)

Otake, N.; Nozaki, O.

1987-01-01

An emergency air filter system of FBR was developed by using a multilayer type filter to protect the function of HEPA filter from clogging due to loading of sodium aerosol. To examine the effect of loading of sodium aerosol on the filter system, sodium aerosol consisting of sodium oxides and the related compound was supplied to the filter system. Several parameters to determine the effectiveness of the multilayer type filter were surveyed. It was confirmed that the emergency air filter system of FBR consisting of the multilayer type filter, a medium filter, HEPA filter with standard size (610 mm x 610 mm) in series could hold 800 g-Na at 1.5 kPa without clogging

Test of precoat filtration technology for treatment of swimming pool water.

Science.gov (United States)

Christensen, Morten Lykkegaard; Klausen, Morten Møller; Christensen, Peter Vittrup

2018-02-01

The technical performance of a precoat filter was compared with that of a traditional sand filter. Particle concentration and size distribution were measured before and after the filtration of swimming pool water. Both the sand and precoat filters could reduce the particle concentration in the effluent. However, higher particle removal efficiency was generally observed for the precoat filter, especially for particles smaller than 10 μm in diameter. Adding flocculant improved the removal efficiency of the sand filter, resulting in removal efficiencies comparable to those of the precoat filter. Three powders, i.e., two types of perlite (Harbolite ® and Aquatec perlite) and cellulose fibers (Arbocel ® ), were tested for the precoat filter, but no significant difference in particle removal efficiency was observed among them. The maximum efficiency was reached within 30-40 min of filtration. The energy required for the pumps increased by approximately 35% over a period of 14 days. The energy consumption could be reduced by replacing the powder on the filter cloth. The sand filter was backwashed once a week, while the powder on the precoat filter was replaced every two weeks. Under these conditions, it was possible to reduce the water used for cleaning by 88% if the precoat filter was used instead of the sand filter.

Complexant Identification in Hanford Waste Simulant Sr/TRU Filtrate

International Nuclear Information System (INIS)

Bannochie, C.J.

2003-01-01

This project was designed to characterize the available multidentate ligand species and metal ion complexes of iron, strontium and manganese formed with the parent chelators, complexing agents and their fragment products. Complex identification was applied to AN-102 and AN-107 filtrate simulants for Hanford waste after an oxidation reaction with sodium permanganate to create a freshly precipitated manganese dioxide solid for adsorption of transuranic elements. Separation efficiency of different ligands was investigated based on the exchange capability of different ion exchange and ion exclusion analytical columns including Dionex IonPac AS-5A, AS-10, AS-11 and AS-6. The elution programs developed with different mobile phase concentrations were based on the change in the effective charge of the anionic species and therefore the retention on the stationary phase. In the present work, qualitative and quantitative assessments of multidentate ligands were investigated. Identification methods for the metal ion complexes responsible for solubilizing Fe, Mn and Sr were applied to aged and fresh simulant waste filtrates. Although concentration measurements of both fresh and 3-week aged filtrates showed that the degradation process occurs mainly due to the harsh chemical environment, it was found that the concentration of iron and manganese did not increase, within the error of the analytical measurements, after three weeks when compared with fresh filtrate

Filtrations of free groups as intersections

OpenAIRE

Efrat, Ido

2013-01-01

For several natural filtrations of a free group S we express the n-th term of the filtration as the intersection of all kernels of homomorphisms from S to certain groups of upper-triangular unipotent matrices. This generalizes a classical result of Grun for the lower central filtration. In particular, we do this for the n-th term in the lower p-central filtration of S.

EM Task 9 - Centrifugal Membrane Filtration

International Nuclear Information System (INIS)

Stevens, B.G.; Stepan, D.J.; Hetland, M.D.

1998-01-01

This project is designed to establish the utility of a novel centrifugal membrane filtration technology for the remediation of liquid mixed waste streams at US Department of Energy (DOE) facilities in support of the DOE Environmental Management (EM) program. The Energy and Environmental Research Center (EERC) has teamed with SpinTek Membrane Systems, Inc., a small business and owner of the novel centrifugal membrane filtration technology, to establish the applicability of the technology to DOE site remediation and the commercial viability of the technology for liquid mixed waste stream remediation. The technology is a uniquely configured process that makes use of ultrafiltration and centrifugal force to separate suspended and dissolved solids from liquid waste streams, producing a filtered water stream and a low-volume contaminated concentrate stream. This technology has the potential for effective and efficient waste volume minimization, the treatment of liquid tank wastes, the remediation of contaminated groundwater plumes, and the treatment of secondary liquid waste streams from other remediation processes, as well as the liquid waste stream generated during decontamination and decommissioning activities

Parking Lot Runoff Quality and Treatment Efficiency of a Stormwater-Filtration Device, Madison, Wisconsin, 2005-07

Science.gov (United States)

Horwatich, Judy A.; Bannerman, Roger T.

2010-01-01

To evaluate the treatment efficiency of a stormwater-filtration device (SFD) for potential use at Wisconsin Department of Transportation (WisDOT) park-and-ride facilities, a SFD was installed at an employee parking lot in downtown Madison, Wisconsin. This type of parking lot was chosen for the test site because the constituent concentrations and particle-size distributions (PSDs) were expected to be similar to those of a typical park-and-ride lot operated by WisDOT. The objective of this particular installation was to reduce loads of total suspended solids (TSS) in stormwater runoff to Lake Monona. This study also was designed to provide a range of treatment efficiencies expected for a SFD. Samples from the inlet and outlet were analyzed for 33 organic and inorganic constituents, including 18 polycyclic aromatic hydrocarbons (PAHs). Samples were also analyzed for physical properties, including PSD. Water-quality samples were collected for 51 runoff events from November 2005 to August 2007. Samples from all runoff events were analyzed for concentrations of suspended sediment (SS). Samples from 31 runoff events were analyzed for 15 constituents, samples from 15 runoff events were analyzed for PAHs, and samples from 36 events were analyzed for PSD. The treatment efficiency of the SFD was calculated using the summation of loads (SOL) and the efficiency ratio methods. Constituents for which the concentrations and (or) loads were decreased by the SFD include TSS, SS, volatile suspended solids, total phosphorous (TP), total copper, total zinc, and PAHs. The efficiency ratios for these constituents are 45, 37, 38, 55, 22, 5, and 46 percent, respectively. The SOLs for these constituents are 32, 37, 28, 36, 23, 8, and 48 percent, respectively. The SOL for chloride was -21 and the efficiency ratio was -18. Six chemical constituents or properties-dissolved phosphorus, chemical oxygen demand, dissolved zinc, total dissolved solids, dissolved chemical oxygen demand, and

Effectiveness of interim stage filter in the exhaust system of glove boxes

International Nuclear Information System (INIS)

Patre, D.K.; Vangara, H.; Thanamani, S.; Gopalakrishnan, R.K.; Mhatre, Amol M.

2018-01-01

All operations in radiochemical laboratories are carried out in containment systems like Glove boxes and Fume hoods. For controlling air contamination two separate air cleaning systems are incorporated. Laboratory has general ventilation system and glove boxes are provided with a negative pressure system (NPS). Glove box exhaust air is passed through three stage filtration systems: in situ, interim and final before discharging to the atmosphere. In addition to the individual HEPA filters of each glove box, there is an interim HEPA filter bank introduced at the laboratory end. This was introduced to reduce a load on main exhaust filter system. Finally the exhaust air is discharged through the final stage HEPA filter located in the filter house through the Stack. The interim HEPA filter bank provides additional protection for the release of particulate activity and reduces load on the final stage filters. In the present work efforts have been put to validate the interim stage filter, which has been introduced, to limit the environmental release

Selecting Cells for Bioartificial Liver Devices and the Importance of a 3D Culture Environment: A Functional Comparison between the HepaRG and C3A Cell Lines.

Science.gov (United States)

van Wenum, Martien; Adam, Aziza A A; Hakvoort, Theodorus B M; Hendriks, Erik J; Shevchenko, Valery; van Gulik, Thomas M; Chamuleau, Robert A F M; Hoekstra, Ruurdtje

2016-01-01

Recently, the first clinical trials on Bioartificial Livers (BALs) loaded with a proliferative human hepatocyte cell source have started. There are two cell lines that are currently in an advanced state of BAL development; HepaRG and HepG2/C3A. In this study we aimed to compare both cell lines on applicability in BALs and to identify possible strategies for further improvement. We tested both cell lines in monolayer- and BAL cultures on growth characteristics, hepatic differentiation, nitrogen-, carbohydrate-, amino acid- and xenobiotic metabolism. Interestingly, both cell lines adapted the hepatocyte phenotype more closely when cultured in BALs; e.g. monolayer cultures produced lactate, while BAL cultures showed diminished lactate production (C3A) or conversion to elimination (HepaRG), and urea cycle activity increased upon BAL culturing in both cell lines. HepaRG-BALs outperformed C3A-BALs on xenobiotic metabolism, ammonia elimination and lactate elimination, while protein synthesis was comparable. In BAL cultures of both cell lines ammonia elimination correlated positively with glutamine production and glutamate consumption, suggesting ammonia elimination was mainly driven by the balance between glutaminase and glutamine synthetase activity. Both cell lines lacked significant urea cycle activity and both required multiple culture weeks before reaching optimal differentiation in BALs. In conclusion, culturing in BALs enhanced hepatic functionality of both cell lines and from these, the HepaRG cells are the most promising proliferative cell source for BAL application.

Separation of nanoparticles: Filtration and scavenging from waste incineration plants.

Science.gov (United States)

Förster, Henning; Thajudeen, Thaseem; Funk, Christine; Peukert, Wolfgang

2016-06-01

Increased amounts of nanoparticles are applied in products of everyday life and despite material recycling efforts, at the end of their life cycle they are fed into waste incineration plants. This raises the question on the fate of nanoparticles during incineration. In terms of environmental impact the key question is how well airborne nanoparticles are removed by separation processes on their way to the bag house filters and by the existing filtration process based on pulse-jet cleanable fibrous filter media. Therefore, we investigate the scavenging and the filtration of metal nanoparticles under typical conditions in waste incineration plants. The scavenging process is investigated by a population balance model while the nanoparticle filtration experiments are realized in a filter test rig. The results show that depending on the particle sizes, in some cases nearly 80% of the nanoparticles are scavenged by fly ash particles before they reach the bag house filter. For the filtration step dust cakes with a pressure drop of 500Pa or higher are found to be very effective in preventing nanoparticles from penetrating through the filter. Thus, regeneration of the filter must be undertaken with care in order to guarantee highly efficient collection of particles even in the lower nanometre size regime. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optimization of suspensions filtration with compressible cake

Directory of Open Access Journals (Sweden)

Janacova Dagmar

2016-01-01

Full Text Available In this paper there is described filtering process for separating reaction mixture after enzymatic hydrolysis to process the chromium tanning waste. Filtration of this mixture is very complicated because it is case of mixture filtration with compressible cake. Successful process strongly depends on mathematical describing of filtration, calculating optimal values of pressure difference, specific resistant of filtration cake and temperature maintenance which is connected with viscosity change. The mathematic model of filtration with compressible cake we verified in laboratory conditions on special filtration device developed on our department.

Visualization and evaluation of flow during water filtration: Parameterization and sensitivity analysis

Directory of Open Access Journals (Sweden)

Bílek Petr

2016-01-01

Full Text Available This paper deals with visualization and evaluation of flow during filtration of water seeded by artificial microscopic particles. Planar laser induced fluorescence (PLIF is a wide spread method for visualization and non-invasive characterization of flow. However the method uses fluorescent dyes or fluorescent particles in special cases. In this article the flow is seeded by non-fluorescent monodisperse polystyrene particles with the diameter smaller than one micrometer. The monodisperse sub-micron particles are very suitable for testing of textile filtration materials. Nevertheless non-fluorescent particles are not useful for PLIF method. A water filtration setup with an optical access to the place, were a tested filter is mounted, was built and used for the experiments. Concentration of particles in front of and behind the tested filter in a laser light sheet measured is and the local filtration efficiency expressed is. The article describes further progress in the measurement. It was carried out sensitivity analysis, parameterization and performance of the method during several simulations and experiments.

Simulation of impaction filtration of aerosol droplets in porous media

NARCIS (Netherlands)

Ghazaryan, L.; Lopez Penha, D.J.; Geurts, Bernardus J.; Stolz, S.; Stolz, Steffen; Winkelmann, Christoph; Pereira, J.C.F; Sequeira, A.; Pereira, J.M.C.

2010-01-01

We report on the development of a method to simulate from first principles the particle filtration efficiency of filters that are composed of structured porous media. We assume that the ratio of particle density to the fluid density is high. We concentrate on the motion of the particles in a laminar

Water Filtration Products

Science.gov (United States)

1986-01-01

American Water Corporation manufactures water filtration products which incorporate technology originally developed for manned space operations. The formula involves granular activated charcoal and other ingredients, and removes substances by catalytic reactions, mechanical filtration, and absorption. Details are proprietary. A NASA literature search contributed to development of the compound. The technology is being extended to a deodorizing compound called Biofresh which traps gas and moisture inside the unit. Further applications are anticipated.

Polyaluminium chloride as an alternative to alum for the direct filtration of drinking water.

Science.gov (United States)

Zarchi, Idit; Friedler, Eran; Rebhun, Menahem

2013-01-01

The efficiency of various polyaluminium chloride coagulants (PACls) was compared to the efficiency of aluminium sulfate (alum) in the coagulation-flocculation process preceding direct filtration in drinking water treatment. The comparative study consisted of two separate yet complementary series of experiments: the first series included short (5-7 h) and long (24 h) filter runs conducted at a pilot filtration plant equipped with large filter columns that simulated full-scale filters. Partially treated surface water from the Sea of Galilee, characterized by very low turbidity (-1 NTU), was used. In the second series of experiments, speciation of aluminium in situ was investigated using the ferron assay method. Results from the pilot-scale study indicate that most PACls were as or more efficient a coagulant as alum for direct filtration of surface water without requiring acid addition for pH adjustment and subsequent base addition for re-stabilizing the water. Consequently, cost analysis of the chemicals needed for the process showed that treatment with PACl would be significantly less costly than treatment with alum. The aluminium speciation experiments revealed that the performance of the coagulant is more influenced by the species present during the coagulation process than those present in the original reagents.

77 FR 48165 - Cooperative Research and Development Agreement (CRADA) Opportunity With the Department of...

Science.gov (United States)

2012-08-13

... perform in-place decontamination of heating, ventilation, and cooling (HVAC) HEPA filtration systems. The... target agents (FMDV and ASFV) and test microorganisms (Bacillus subtilis, Vaccinia Virus, Geobacillius stearothermophilus, and potentially other commercially available spore strips) will be used to test the efficacy of...

Health Benefits of Particle Filtration

Energy Technology Data Exchange (ETDEWEB)

Fisk, William J.

2013-10-01

The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also, reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percent age improvement in health outcomes is typically modest, for example, 7percent to 25percent. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

Health Benefits of Particle Filtration

Energy Technology Data Exchange (ETDEWEB)

Fisk, William J.

2013-10-01

The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percentage improvement in health outcomes is typically modest, e.g., 7percent to 25percent. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

Filtration Behaviour and Fouling Mechanisms of Polysaccharides

Directory of Open Access Journals (Sweden)

Sondus Jamal

2014-07-01

Full Text Available This study investigated filtration behaviors of polysaccharides solutions, both alone and in mixture with proteins, in the short-time constant flux filtration with the focus on factors affecting the transmembrane pressure (TMP increase rate, the irreversible filtration resistance, and the membrane rejection behavior. The results showed that the TMP increase rates in the short-time constant flux filtration of alginate solutions were significantly affected by the calcium addition, alginate concentration, and flux. Although the addition of calcium resulted in a decrease in the TMP increase rate, it was found that the irreversible fouling developed during the filtration increased with the calcium addition, implying that the double-sided effect of calcium on membrane filtration and that the TMP increase rate observed in the filtration does not always reflect the irreversible membrane fouling development. It was also found that for the filtration of solutions containing mixed alginate and BSA, alginate exerted a dominant effect on the TMP increase rate and the membrane exhibited a reduced rejection to both alginate and BSA molecules compared to that in the filtration of the pure alginate or BSA.

Filtration of sodium-fire aerosols

International Nuclear Information System (INIS)

Alexas, A.; Jordan, S.; Lindner, W.

1979-01-01

Different filter devices have been developed and tested with respect to their use in the off-gas system of liquid-metal fast breeder reactors to prevent the escape of sodium-fire aerosols that might be formed in case of an accident. The testing results have shown that the use of a multilayer sand bed filter is still the best method to filter limited amounts of sodium-fire aerosols over a long operating time. Efficiencies on the order of 99.98 and 98.8% were reached for loading capacities of 500 and 1000 g/m 2 , respectively. Unlimited amounts of sodium-fire aerosols can be filtered by wet scrubbers with an efficiency of 70% per scrubber stage. Fiberglas filters connot be used for the filtration of sodium-fire aerosols over a long operating time because the filter material can be destroyed after several days of operating

Health Benefits of Particle Filtration

OpenAIRE

Fisk, William J.

2013-01-01

The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and as...

Relation Between Filtration and Soil Consolidation Theories

Directory of Open Access Journals (Sweden)

Strzelecki Tomasz

2015-03-01

Full Text Available This paper presents a different, than commonly used, form of equations describing the filtration of a viscous compressible fluid through a porous medium in isothermal conditions. This mathematical model is compared with the liquid flow equations used in the theory of consolidation. It is shown that the current commonly used filtration model representation significantly differs from the filtration process representation in Biot’s and Terzaghi’s soil consolidation models, which has a bearing on the use of the methods of determining the filtration coefficient on the basis of oedometer test results. The present analysis of the filtration theory equations should help interpret effective parameters of the non-steady filtration model. Moreover, equations for the flow of a gas through a porous medium and an interpretation of the filtration model effective parameters in this case are presented.

Grey water treatment in urban slums by a filtration system: optimisation of the filtration medium.

Science.gov (United States)

Katukiza, A Y; Ronteltap, M; Niwagaba, C B; Kansiime, F; Lens, P N L

2014-12-15

Two uPVC columns (outer diameter 160 cm, internal diameter 14.6 cm and length 100 cm) were operated in parallel and in series to simulate grey water treatment by media based filtration at unsaturated conditions and constant hydraulic loading rates (HLR). Grey water from bathroom, laundry and kitchen activities was collected from 10 households in the Bwaise III slum in Kampala (Uganda) in separate containers, mixed in equal proportions followed by settling, prior to transferring the influent to the tanks. Column 1 was packed with lava rock to a depth of 60 cm, while column 2 was packed with lava rock (bottom 30 cm) and silica sand, which was later replaced by granular activated carbon (top 30 cm) to further investigate nutrient removal from grey water. Operating the two filter columns in series at a HLR of 20 cm/day resulted in a better effluent quality than at a higher (40 cm/day) HLR. The COD removal efficiencies by filter columns 1 and 2 in series amounted to 90% and 84% at HLR of 20 cm/day and 40 cm/day, respectively. TOC and DOC removal efficiency amounted to 77% and 71% at a HLR of 20 cm/day, but decreased to 72% and 67% at a HLR of 40 cm/day, respectively. The highest log removal of Escherichia coli, Salmonella sp. and total coliforms amounted to 3.68, 3.50 and 3.95 at a HLR of 20 cm/day respectively. The overall removal of pollutants increased with infiltration depth, with the highest pollutant removal efficiency occurring in the top 15 cm layer. Grey water pre-treatment followed by double filtration using coarse and fine media has the potential to reduce the grey water pollution load in slum areas by more than 60%. Copyright © 2014 Elsevier Ltd. All rights reserved.

Particle filtration in consolidated granular systems

International Nuclear Information System (INIS)

Schwartz, L.M.; Wilkinson, D.J.; Bolsterli, M.; Hammond, P.

1993-01-01

Grain-packing algorithms are used to model the mechanical trapping of dilute suspensions of particles by consolidated granular media. We study the distribution of filtrate particles, the formation of a damage zone (internal filter cake), and the transport properties of the host--filter-cake composite. At the early stages of filtration, our simulations suggest simple relationships between the structure of the internal filter cake and the characteristics of the underlying host matrix. These relationships are then used to describe the dynamics of the filtration process. Depending on the grain size and porosity of the host matrix, calculated filtration rates may either be greater than (spurt loss) or less than (due to internal clogging) those predicted by standard surface-filtration models

Production of a ruminant protein supplement by anaerobic fermentation of feedlot waste filtrate

Energy Technology Data Exchange (ETDEWEB)

Reddy, C.A.; Erdman, M.D.

1977-01-01

In studies initiated to develop simple and efficient procedures for the production of feed supplements, it was shown that the filtrate from feedlot wastes diluted with water and filtered could be fermented under anaerobic conditions by mixed rumen bacteria, Lactobacilli, or natural microflora from the feedlot wastes to produce a protein-rich feed supplement. The filtrate is low in carbohydrate and therefore supplemental carbohydrate in the form of whey, molasses, starch from potato processing wastes, or corn starch is necessary. Rigid anaerobic conditions need not be maintained nor must aseptic conditions be observed. (JSR)

Turbidity removal: Gravel and charcoal as roughing filtration media

Directory of Open Access Journals (Sweden)

Josiah A. Adeyemo

2010-10-01

Full Text Available Roughing filtration is an important pre-treatment process for wastewater, because it efficiently separates fine solid particles over prolonged periods, without the addition of chemicals. For this study, a pilot plant was designed at Delmas Coal Mine in the Mpumalanga province of South Africa. The design and sizing of the pilot plant was guided by Wegelin’s design criteria. Gravel was used as a control medium because it is one of the most commonly used roughing filter media and because it was used in developing the criteria. We compared the performance of gravel as a filter medium to that of another locally available material, charcoal, for the removal of turbidity in wastewater. The pilot plant was monitored continuously for 90 days from commissioning until the end of the project. The overall performance of the roughing filter in turbidity removal, using gravel or charcoal, was considered efficient for the pre-treatment of waste water. Charcoal performed slightly better than gravel as a filter medium for the removal of turbidity, possibly because charcoal has a slightly higher specific surface area and porosity than gravel, which could enhance sedimentation and other filtration processes, such as adsorption, respectively.

Method for HEPA filter leak scanning with differentiating aerosol detector

Energy Technology Data Exchange (ETDEWEB)

Kovach, B.J.; Banks, E.M.; Wikoff, W.O. [NUCON International, Inc., Columbus, OH (United States)

1997-08-01

While scanning HEPA filters for leaks with {open_quotes}Off the Shelf{close_quote} aerosol detection equipment, the operator`s scanning speed is limited by the time constant and threshold sensitivity of the detector. This is based on detection of the aerosol density, where the maximum signal is achieved when the scanning probe resides over the pinhole longer than several detector time-constants. Since the differential value of the changing signal can be determined by observing only the first small fraction of the rising signal, using a differentiating amplifier will speed up the locating process. The other advantage of differentiation is that slow signal drift or zero offset will not interfere with the process of locating the leak, since they are not detected. A scanning hand-probe attachable to any NUCON{reg_sign} Aerosol Detector displaying the combination of both aerosol density and differentiated signal was designed. 3 refs., 1 fig.

The use of an air filtration system in podiatry clinics.

Science.gov (United States)

McLarnon, Nichola; Burrow, Gordon; Maclaren, William; Aidoo, Kofi; Hepher, Mike

2003-06-01

A small-scale study was conducted to ascertain the efficiency and effectiveness of an air filtration system for use in podiatry/chiropody clinics (Electromedia Model 35F (A), Clean Air Ltd, Scotland, UK). Three clinics were identified, enabling comparison of data between podiatry clinics in the West of Scotland. The sampling was conducted using a portable Surface Air Sampler (Cherwell Laboratories, Bicester, UK). Samples were taken on two days at three different times before and after installation of the filtration units. The global results of the study indicate the filter has a statistically significant effect on microbial counts, with an average percentage decrease of 65%. This study is the first time, to the authors' knowledge, such a system has been tested within podiatric practice.

Flexographic newspaper deinking : treatment of wash filtrate effluent by membrane technology

Science.gov (United States)

B. Chabot; G.A. Krishnagopalan; S. Abubakr

1999-01-01

Ultrafiltration was investigated as a means to remove flexographic ink pigments from wash filtrate effluent generated from various mixtures of flexographic and offset old newspapers from deinking operations. Membrane separation efficiency was assessed from permeate flux, fouling rate, and ease of membrane regeneration (cleaning). Ultrafiltration was capable of...

Health benefits of particle filtration.

Science.gov (United States)

Fisk, W J

2013-10-01

The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also, reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percentage improvement in health outcomes is typically modest, for example, 7% to 25%. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air. Published 2013. This article is a US Government work and is in the public domain in the USA.

The case for improved HEPA-filter mechanical performance standards revisited

Energy Technology Data Exchange (ETDEWEB)

Ricketts, C.I.; Smith, P.R. [New Mexico State Univ., Las Cruces, NM (United States)

1997-08-01

Under benign operating conditions, High Efficiency Particulate Air (HEPA) filter units serve as reliable and relatively economical components in the air cleaning systems of nuclear facilities worldwide. Despite more than four decades of filter-unit evaluation and improvements, however, the material strength characteristics of the glass fiber filter medium continue to ultimately limit filter functional reliability. In worst-case scenarios involving fire suppression, loss-of-coolant accidents (LOCA`s), or exposure to shock waves or tornado induced flows, rupture of the filter medium of units meeting current qualification standards cannot be entirely ruled out. Even under so-called normal conditions of operation, instances of filter failure reported in the literature leave open questions of filter-unit reliability. Though developments of filter units with improved burst strengths have been pursued outside the United States, support for efforts in this country has been comparatively minimal. This despite user requests for filters with greater moisture resistance, for example. Or the fact that conventional filter designs result in not only the least robust component to be found in a nuclear air cleaning system, but also the one most sensitive to the adverse effects of conditions deviating from those of normal operation. Filter qualification-test specifications of current codes, standards, and regulatory guidelines in the United States are based primarily upon research performed in a 30-year period beginning in the 1950`s. They do not seem to reflect the benefits of the more significant developments and understanding of filter failure modes and mechanisms achieved since that time. One overseas design, based on such knowledge, has proven reliability under adverse operating conditions involving combined and serial challenges. Its widespread use, however, has faltered on a lack of consensus in upgrading filter performance standards. 34 refs., 2 figs., 3 tabs.

Experimental Investigation of In Situ Cleanable or Regenerative Filters for High Level Radioactive Waste Tanks

International Nuclear Information System (INIS)

Adamson, D.J.

2000-01-01

test campaign. Both the sintered metal and ceramic filters passed the challenge test with the efficiency of a conventional HEPA filter each time. The sintered metal and ceramic filters not only can be cleaned in situ but also hold great potential as a long life alternative to conventional HEPA filters. The Defense Nuclear Facility Safety Board Technical Report, entitled HEPA Filters Used in the Department of Energy's Hazardous Facilities, found that conventional glass fiber HEPA filters are structurally weak and easily damaged by water or fire. The structurally stronger sintered metal and ceramic filter media would reduce the potential of a catastrophic HEPA filter failure due to filter media breakthrough in the process ventilation system. An in situ regenerable system may also be applicable to recovery of nuclear materials, such as plutonium, collected on glove box exhaust HEPA filters. This innovative approach of the in situ regenerable filtration system may be a significant improvement upon the shortfalls of conventional disposable HEPA filters

Direct filtration of Biesbosch water and Algae and water treatment in the Netherlands : 3rd Direct Filtration Seminar

NARCIS (Netherlands)

Petrusevski, B.; Vlaski, A.; Van Breemen, A.N.; Alaerts, G.J.

1993-01-01

This presentation summarises basic information on direct filtration, and demonstrates the main research findings, related to the performance of simple in-line direct filtration. The results reported are part of a comprehensive ongoing research programm "Direct filtration of Biesbosch water"

Portable field water sample filtration unit

International Nuclear Information System (INIS)

Hebert, A.J.; Young, G.G.

1977-01-01

A lightweight back-packable field-tested filtration unit is described. The unit is easily cleaned without cross contamination at the part-per-billion level and allows rapid filtration of boiling hot and sometimes muddy water. The filtration results in samples that are free of bacteria and particulates and which resist algae growth even after storage for months. 3 figures

Magnetic-seeding filtration

International Nuclear Information System (INIS)

Depaoli, D.

1996-01-01

This task will investigate the capabilities of magnetic-seeding filtration for the enhanced removal of magnetic and nonmagnetic particulates from liquids. This technology appies to a wide range of liquid wastes, including groundwater, process waters, and tank supernatant. Magnetic-seeding filtration can be used in several aspects of treatment, such as (1) removal of solids, particularly those in the colloidal-size range that are difficult to remove by conventional means; (2) removal of contaminants by precipitation processes; and (3) removal of contaminants by sorption processes

Controlling inclusions through filtration in investment casting process

International Nuclear Information System (INIS)

Ahmad, R.; Marshall, R.I.

2004-01-01

A technique for the placement of a ceramic foam filter in the feeding up of investment mould was developed which proved quite efficient in removing smaller and major inclusions through various filtration modes. Contaminated old aluminum scrap was used to prepare the melt without the addition of any cleansing and covering fluxes and the main reason was to produce more and more inclusions. Vigorous stirring was also intentionally carried out to form as much oxides as possible. During present research work effective filtration was observed. No leakage through sides of the filter occurred and similarly no choking was seen during feeding of molten metal. Microstructural studies showed the maximum retention of inclusions not only on the surface of filters but also within the various channels of the main body of the filter. The microstructures taken from the filtered test pieces were free from inclusions, which showed the effectiveness and proper placement of the filter. (author)

Latest aspects of mechanical filtration

Directory of Open Access Journals (Sweden)

Stanislav Koláček

2013-01-01

Full Text Available The aim of this study was to describe and unify all knowledge about mechanic filtration. The first part deals with the parameters and properties of filtration. Here some important basic concepts are explained such as pressure gradient, filter life, etc. There’s also a description of convenient filtration technology for coarse and fine materials, such as sand, smoke or soot. The second part primarily focuses on the real use and application of filters for liquid and gaseous media. The differences in construction between different types of filters for filtration of fuels, oils, hydraulic fluids, air and cabin filters are described. The last section is focused mainly on new materials for the production of filters. These materials are ceramic or nanomaterials, which can actually be enriched for example with antibacterial silver or some fungicides.

Simulation of the filtration mechanism of hyaluronic acid in total knee prosthesis

International Nuclear Information System (INIS)

Paolo, J Di; Berli, M E; Campana, D M; Ubal, S; Cardenes, L D

2007-01-01

Polyethylene (UHMWPE) wear in current knee prosthesis causes prosthesis loosening after no more than 15 years. In this work, a steady state one-dimensional lubrication model with non- Newtonian fluid, porous elastic layer on tibial component, ultra-filtration mechanism of fluid and some features of the surface roughness is studied through a numerical technique based on the Finite Element Method. The results show that the UHMWPE stiffness makes difficult the lubrication mechanism of the artificial joint and promotes abrasive and fatigue wear. Nevertheless, the use of compliant porous materials on the tibial component could reduce friction and wear. Moreover, the ultra-filtration mechanism promotes efficiency on the joint

Liver Progenitor Cell Line HepaRG Differentiated in a Bioartificial Liver Effectively Supplies Liver Support to Rats with Acute Liver Failure

NARCIS (Netherlands)

Nibourg, Geert A. A.; Chamuleau, Robert A. F. M.; van der Hoeven, Tessa V.; Maas, Martinus A. W.; Ruiter, An F. C.; Lamers, Wouter H.; Oude Elferink, Ronald P. J.; van Gulik, Thomas M.; Hoekstra, Ruurdtje

2012-01-01

A major roadblock to the application of bioartificial livers is the need for a human liver cell line that displays a high and broad level of hepatic functionality. The human bipotent liver progenitor cell line HepaRG is a promising candidate in this respect, for its potential to differentiate into

40 CFR 141.174 - Filtration sampling requirements.

Science.gov (United States)

2010-07-01

... PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection... water system subject to the requirements of this subpart that provides conventional filtration treatment... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Filtration sampling requirements. 141...

40 CFR 141.73 - Filtration.

Science.gov (United States)

2010-07-01

... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Filtration and Disinfection § 141.73 Filtration. A public water system that uses a surface water source or a ground water source under the direct influence of surface water...

Efficiency and Loading Evaluation of High Efficiency Mist Eliminators (HEME) - 12003

Energy Technology Data Exchange (ETDEWEB)

Giffin, Paxton K.; Parsons, Michael S.; Waggoner, Charles A. [Institute for Clean Energy Technology, Mississippi State University, 205 Research Blvd Starkville, MS 39759 (United States)

2012-07-01

High efficiency mist eliminators (HEME) are filters primarily used to remove moisture and/or liquid aerosols from an air stream. HEME elements are designed to reduce aerosol and particulate load on primary High Efficiency Particulate Air (HEPA) filters and to have a liquid particle removal efficiency of approximately 99.5% for aerosols down to sub-micron size particulates. The investigation presented here evaluates the loading capacity of the element in the absence of a water spray cleaning system. The theory is that without the cleaning system, the HEME element will suffer rapid buildup of solid aerosols, greatly reducing the particle loading capacity. Evaluation consists of challenging the element with a waste surrogate dry aerosol and di-octyl phthalate (DOP) at varying intervals of differential pressure to examine the filtering efficiency of three different element designs at three different media velocities. Also, the elements are challenged with a liquid waste surrogate using Laskin nozzles and large dispersion nozzles. These tests allow the loading capacity of the unit to be determined and the effectiveness of washing down the interior of the elements to be evaluated. (authors)

"Chemistry in a spinneret" to fabricate hollow fibers for organic solvent filtration

NARCIS (Netherlands)

Dutczak, S.M.; Tanardi, Cheryl; Kopec, K.K.; Wessling, Matthias; Stamatialis, Dimitrios

2012-01-01

Organic solvent filtration (OSF) is a very efficient separation technique with high potential in many branches of industry. Currently the choice of the commercial membranes is limited only to a few flat sheet membranes and spiral wound modules. It is generally known that a membrane in hollow fiber

40 CFR 141.719 - Additional filtration toolbox components.

Science.gov (United States)

2010-07-01

... taken from a surface water or GWUDI source. A cap, such as GAC, on a single stage of filtration is not... separate stage of filtration if both filtration stages treat entire plant flow taken from a surface water... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Additional filtration toolbox...

High efficiency particulate removal with sintered metal filters

International Nuclear Information System (INIS)

Kirstein, B.E.; Paplawsky, W.J.; Pence, D.T.; Hedahl, T.G.

1981-01-01

Because of their particle removal efficiencies and durability, sintered metal filters have been chosen for high efficiency particulate air (HEPA) filter protection in the off-gas treatment system for the proposed Idaho National Engineering Laboratory Transuranic Waste Treatment Facility. Process evaluation of sintered metal filters indicated a lack of sufficient process design data to ensure trouble-free operation. Subsequence pilot scale testing was performed with flyash as the test particulate. The test results showed that the sintered metal filters can have an efficiency greater than 0.9999999 for the specific test conditions used. Stable pressure drop characteristics were observed in pulsed and reversed flow blowback modes of operation. Over 4900 hours of operation were obtained with operating conditions ranging up to approximately 90 0 C and 24 vol % water vapor in the gas stream

Replacement of HEPA Filters at the LANL CMR Facility: Risks Reduced by Comprehensive Waste Characterization

International Nuclear Information System (INIS)

Corpion, J.; Barr, A.; Martinez, P.; Bader, M.

2002-01-01

In March 2001, the Los Alamos National Laboratory (LANL) completed the replacement of 720 radioactively contaminated HEPA filters for $5.7M. This project was completed five months ahead of schedule and $6.0M under budget with no worker injuries or contaminations. Numerous health and safety, environmental, and waste disposal problems were overcome, including having to perform work in a radioactively contaminated work environment, that was also contaminated with perchlorates (potential explosive). High waste disposal costs were also an issue. A project risk analysis and government cost estimate determined that the cost of performing the work would be $11.8M. To reduce risk, a $1.2M comprehensive condition assessment was performed to determine the degree of toxic and radioactive contamination trapped on the HEPA filters; and to determine whether explosive concentrations of perchlorates were present. Workers from LANL and personnel from Waldheim International of Knoxville, TN collected hundreds of samples wearing personnel protective gear against radioactive, toxic, and explosive hazards. LANL also funded research at the New Mexico Institute of Mining and Technology to determine the explosivity of perchlorates. The data acquired from the condition assessment showed that toxic metals, toxic organic compounds, and explosive concentrations of perchlorates were absent. The data also showed that the extent of actinide metal contamination was less than expected, reducing the potential of transuranic waste generation by 50%. Consequently, $4.2M in cost savings and $1.8M in risk reduction were realized by increased worker productivity and waste segregation

Filtration by eyelashes

Science.gov (United States)

Vistarakula, Krishna; Bergin, Mike; Hu, David

2010-11-01

Nearly every mammalian and avian eye is rimmed with lashes. We investigate experimentally the ability of lashes to reduce airborne particle deposition in the eye. We hypothesize that there is an optimum eyelash length that maximizes both filtration ability and extent of peripheral vision. This hypothesis is tested using a dual approach. Using preserved heads from 36 species of animals at the American Museum of Natural History, we determine the relationship between eye size and eyelash geometry (length and spacing). We test the filtration efficacy of these geometries by deploying outdoor manikins and measuring particle deposition rate as a function of eyelash length.

Low-cost multi-stage filtration enhanced by coagulation-flocculation in upflow gravel filtration

Directory of Open Access Journals (Sweden)

L. D. Sánchez

2012-12-01

Full Text Available This paper assesses the operational and design aspects of coagulation and flocculation in upflow gravel filters (CF-UGF in a multi-stage filtration (MSF plant. This study shows that CF-UGF units improve the performance of MSF considerably, when the system operates with turbidity above 30 NTU. It strongly reduces the load of particulate material before the water enters in the slow sand filters (SSF and therewith avoids short filter runs and prevents early interruption in SSF operations. The removal efficiency of turbidity in the CF-UGF with coagulant was between 85 and 96%, whereas the average efficiency without coagulant dosing was 46% (range: 21–76%. Operating with coagulant also improves the removal efficiency for total coliforms, E-coli and HPC. No reduction was observed in the microbial activity of the SSF, no obstruction of the SSF bed was demonstrated and SSF runs were maintained between 50 and 70 days for a maximum head loss of 0.70 m. The most important advantage is the flexibility of the system to operate with and without coagulant according to the influent turbidity. It was only necessary for 20% of the time to operate with the coagulant. The CF-UGF unit represented 7% of total construction costs and the O&M cost for the use of coagulant represented only 0.3%.

Study on DOP substitutes for leaking rate testing of HEPA filter used in nuclear air cleaning systems

International Nuclear Information System (INIS)

Qiu Dangui; Zhang Jirong; Hou Jianrong; Qiao Taifei; Shen Dapeng; Shi Yingxia

2012-01-01

Based on an extensive investigation over available literatures concerning HEPA filter testing, PEG400, SHELL on dina oil 15 and P.a. were chosen as candidates for Dop substitutes, and on which a series of tests were conducted about their aerosol conversion rate, particle size distribution, Dop detector response and leaking rate in H EPA filter. With consideration of technical properties, safety performance and economy, homemade P.a. is finally selected as the best substitute for Dop among the three. (authors)

Side Stream Filtration for Cooling Towers

Energy Technology Data Exchange (ETDEWEB)

None

2012-10-20

This technology evaluation assesses side stream filtration options for cooling towers, with an objective to assess key attributes that optimize energy and water savings along with providing information on specific technology and implementation options. This information can be used to assist Federal sites to determine which options may be most appropriate for their applications. This evaluation provides an overview of the characterization of side stream filtration technology, describes typical applications, and details specific types of filtration technology.

Cake creep during filtration of flocculated manure

DEFF Research Database (Denmark)

Christensen, Morten Lykkegaard; Keiding, Kristian

is filtered. Hence, it is not possible to scale up the experiments, and it is therefore difficult to optimize the flocculation and estimate the needed filter media area. Similar problems have been observed when sewage sludge and synthetic core-shell colloids are filtered, and it has been suggested......, and the mixing procedure affect the result, and lab-scale experiments are often used to study how these pre-treatments influence the filtration process. However, the existing mathematical filtration models are based on filtration of inorganic particles and cannot simulate the filtration data obtained when manure...

New collector efficiency equation for colloid filtration in both natural and engineered flow conditions

Science.gov (United States)

Nelson, Kirk E.; Ginn, Timothy R.

2011-05-01

A new equation for the collector efficiency (η) of the colloid filtration theory (CFT) is developed via nonlinear regression on the numerical data generated by a large number of Lagrangian simulations conducted in Happel's sphere-in-cell porous media model over a wide range of environmentally relevant conditions. The new equation expands the range of CFT's applicability in the natural subsurface primarily by accommodating departures from power law dependence of η on the Peclet and gravity numbers, a necessary but as of yet unavailable feature for applying CFT to large-scale field transport (e.g., of nanoparticles, radionuclides, or genetically modified organisms) under low groundwater velocity conditions. The new equation also departs from prior equations for colloids in the nanoparticle size range at all fluid velocities. These departures are particularly relevant to subsurface colloid and colloid-facilitated transport where low permeabilities and/or hydraulic gradients lead to low groundwater velocities and/or to nanoparticle fate and transport in porous media in general. We also note the importance of consistency in the conceptualization of particle flux through the single collector model on which most η equations are based for the purpose of attaining a mechanistic understanding of the transport and attachment steps of deposition. A lack of sufficient data for small particles and low velocities warrants further experiments to draw more definitive and comprehensive conclusions regarding the most significant discrepancies between the available equations.

Riverbed Clogging and Sustainability of Riverbank Filtration

Directory of Open Access Journals (Sweden)

Thomas Grischek

2016-12-01

Full Text Available Clogging refers to a reduction of riverbed hydraulic conductivity. Due to difficulties in determining the thickness of the clogging layer, the leakage coefficient (L is introduced and used to quantify the recoverable portion of bank filtrate. L was determined at several riverbank filtration (RBF sites in field tests and using an analytical solution. Results were compared with data from similar experiments in the early 1970s and 1991–1993. In the 1980s, severe river water pollution in conjunction with high water abstraction led to partly unsaturated conditions beneath the riverbed. A leakage coefficient L of 5 × 10−7 s−1 was determined. After water quality improvement, L increased to 1–1.5 × 10−6 s−1. An alternative, cost and time efficient method is presented to estimate accurate leakage coefficients. The analytical solution is based on groundwater level monitoring data from observation wells next to the river, which can later feed into numerical models. The analytical approach was able to reflect long-term changes as well as seasonal variations. Recommendations for its application are given based on experience.

Reliability and Validity of the SE-HEPA: Examining Physical Activity- and Healthy Eating-Specific Self-Efficacy among a Sample of Preadolescents

Science.gov (United States)

Steele, Michael M.; Burns, Leonard G.; Whitaker, Brandi N.

2013-01-01

Objective. The purpose of this study was to examine the psychometric properties of the self-efficacy for healthy eating and physical activity measure (SE-HEPA) for preadolescents. Method. The reliability of the measure was examined to determine if the internal consistency of the measure was adequate (i.e., [alpha]s greater than 0.70). Next, in an…

21 CFR 177.2910 - Ultra-filtration membranes.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ultra-filtration membranes. 177.2910 Section 177... Components of Articles Intended for Repeated Use § 177.2910 Ultra-filtration membranes. Ultra-filtration membranes identified in paragraphs (a)(1), (a)(2), (a)(3), and (a)(4) of this section may be safely used in...

Integration of membrane filtration and photoelectrocatalysis using a TiO{sub 2}/carbon/Al{sub 2}O{sub 3} membrane for enhanced water treatment

Energy Technology Data Exchange (ETDEWEB)

Wang, Guanlong; Chen, Shuo, E-mail: shuochen@dlut.edu.cn; Yu, Hongtao; Quan, Xie

2015-12-15

Highlights: • Membrane filtration was integrated with photoelectrocatalysis for water treatment. • This integrated process (PECM) displays good antifouling capacity in NOMs removal. • PECM process enables efficient removal of chemical contaminants (e.g., RhB). • Enhanced charge separation of PECM process leads to its improved performance. - Abstract: Coupling membrane filtration with photocatalysis provides multifunction involving filtration and photocatalytic degradation for removing pollutants from water, but the performance of photocatalytic membrane is limited due to the quick recombination of photogenerated electron-holes in photocatalytic layer. Herein, a TiO{sub 2}/carbon/Al{sub 2}O{sub 3} membrane was designed and constructed through sequentially depositing graphitic carbon layer with good electro-conductivity and TiO{sub 2} nanoparticles layer with photocatalytic activity on Al{sub 2}O{sub 3} membrane support. When light irradiated on the membrane with a voltage supply, the photogenerated electrons could be drained from photocatalytic layer and separated with holes efficiently, thus endowing the membrane with photoelectrocatalytic function. Membrane performance tests indicated that the photoelectrocatalytic membrane filtration (PECM) showed improved removal of natural organic matters (NOMs) and permeate flux with increasing voltage supply. For PECM process at 1.0 V, its NOMs removal was 1.2 or 1.7 times higher than that of filtration with UV irradiation or filtration alone, and its stable permeate flux was 1.3 or 3 times higher than that of filtration with UV irradiation or filtration alone. Moreover, the PECM process exhibited special advantage in removing organic chemicals (e.g., Rhodamine B), which displayed 1.3 or 3 times higher removal than that of filtration with UV irradiation or filtration alone.

Potential uses of high gradient magnetic filtration for high-temperature water purification in boiling water reactors

International Nuclear Information System (INIS)

Elliott, H.H.; Holloway, J.H.; Abbott, D.G.

1979-01-01

Studies of various high-temperature filter devices indicate a potentially positive impact for high gradient magnetic filtration on boiling water reactor radiation level reduction. Test results on in-plant water composition and impurity crystallography are presented for several typical boiling water reactors (BWRs) on plant streams where high-temperature filtration may be particularly beneficial. An experimental model on the removal of red iron oxide (hematite) from simulated reactor water with a high gradient magnetic filter is presented, as well as the scale-up parameters used to predict the filtration efficiency on various high temperature, in-plant streams. Numerical examples are given to illustrate the crud removal potential of high gradient magnetic filters installed at alternative stream locations under typical, steady-state, plant operating conditions

DQE of wireless digital detectors: Comparative performance with differing filtration schemes

International Nuclear Information System (INIS)

Samei, Ehsan; Murphy, Simon; Christianson, Olav

2013-01-01

Purpose: Wireless flat panel detectors are gaining increased usage in portable medical imaging. Two such detectors were evaluated and compared with a conventional flat-panel detector using the formalism of the International Electrotechnical Commission (IEC 62220-1) for measuring modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE) using two different filtration schemes.Methods: Raw images were acquired for three image receptors (DRX-1C and DRX-1, Carestream Health; Inc., Pixium 4600, Trixell) using a radiographic system with a well-characterized output (Philips Super80 CP, Philips Healthcare). Free in-air exposures were measured using a calibrated radiation meter (Unfors Mult-O-Meter Type 407, Unfors Instruments AB). Additional aluminum filtration and a new alternative combined copper-aluminum filtration were used to conform the x ray output to IEC-specified beam quality definitions RQA5 and RQA9. Using the IEC 62220-1 formalism, each detector was evaluated at X N /2, X N , and 2X N , where the normal exposure level to the detector surface (X N ) was set to 8.73 μGy (1.0 mR). The prescribed edge test device was used to evaluate the MTF, while the NNPS was measured using uniform images. The DQE was then calculated from the MTF and NNPS and compared across detectors, exposures, and filtration schemes.Results: The three DR systems had largely comparable MTFs with DRX-1 demonstrating lower values above 1.0 cycles/mm. At each exposure, DRX-1C and Pixium detectors demonstrated better noise performance than that of DRX-1. Zero-frequency DQEs for DRX-1C, Pixium, and DRX-1 detectors were approximately 74%, 63%, and 38% for RQA5 and 50%, 42%, and 28% for RQA9, respectively.Conclusions: DRX-1C detector exhibited superior DQE performance compared to Pixium and DRX-1. In terms of filtration, the alternative filtration was found to provide comparable performance in terms of rank ordering of different detectors with

Characterization, Washing, Leaching, and Filtration of C-104 Sludge

Energy Technology Data Exchange (ETDEWEB)

KP Brooks; PR Bredt; GR Golcar; SA Hartley; LK Jagoda; KG Rappe; MW Urie

2000-06-09

Approximately 1,400 g of wet Hanford Tank C-104 Sludge was evaluated by Battelle for the high-level waste (HLW) pretreatment processes of ultrafiltration, dilute caustic washing, and elevated-temperature caustic leaching. The filterability of diluted C-104 sludge was measured with a 0.1-{micro}m sintered metal Mott filter using a 24-inch-long, single-element, crossflow filtration system (cells unit filter [CUF]). While the filtrate was being recirculated prior to washing and leaching, a 6.9 wt% solids slurry was evaluated with a matrix of seven 1-hour conditions of varying trans-membrane pressure (30 to 70 psid) and axial velocity (9 to 15 ft/s). The filtrate flux and backpulse efficiency were determined for each condition. The slurry was concentrated to 23 wt% solids, a second matrix of six 1-hour conditions was performed, and data analogous to that recorded in the first matrix were obtained. The low-solids-concentration matrix produced filtrate flux rates that ranged from 0.038 to 0.083 gpm/ft{sup 2}. The high-solids-concentration matrix produced filtrate flux rates that ranged from 0.0095 to 0.0172 gpm/ft{sup 2}. In both cases, the optimum filtrate flux was at the highest axial velocity (15 ft/s) and transmembrane pressure had little effect. Nearly all of the measured filtrate fluxes were more than an order of magnitude greater than the required plant flux for C-104 of 0.00126 gpm/ft{sup 2}. In both matrices, the filtrate flux appeared to be proportional to axial velocity, and the permeability appeared to be inversely proportional to the trans-membrane pressure. The first test condition was repeated as the last test condition for each matrix. In both cases, there was a significant decrease in filtrate flux, indicating some filter fouling during the test matrix that could not be removed by backpulsing alone, although the backpulse number and duration were not optimized. Following testing of these two matrices, the material was washed within the CUF by

In-Water Hull Cleaning & Filtration System

Science.gov (United States)

George, Dan

2015-04-01

through a multi stage filtration unit on the surface. Solids greater than 50 micron are separated through a 1st stage separator and deposited into a disposal bin. Filtrate is then pumped through a series of high flow, back-flushable filters that remove particulate material greater than 5 micron. After the 1st and 2nd stage filtration the filtrate is then disinfected by passing through an automated UV reactor where the treated water is then released back into the ocean. This advancement in hull cleaning technology will allow vessels to be cleaned in areas where dry docking is not possible or viable along with being a preventive measure to reduce Biofouling in the environment. The in-water hull cleaning system certainly has earned its place as being an innovative leader in improving efficiencies and reducing environmental impact. https://www.linkedin.com/groups?mostRecent=&gid=6724648&trk=my_groups-tile-flipgrp

Development of real time detector for fluorescent particles

Energy Technology Data Exchange (ETDEWEB)

Prevost, C.; Vendel, J. [Institut de Protection et de Surete Nucleaire, Gif-Sur-Yvette (France); Seigneur, A. [LETI, Gif-Sur-Yvette (France)

1997-08-01

Aerosols tagged by a fluorescent dye are a worthwhile tool within the framework of ventilation and filtration studies. The detection in real time of a specific particulate tracer allows characterization of ventilation behaviour such as air change rate, the determination of a good or bad mixing zone and transfer coefficient, or the determination of the decontamination factor for High Efficiency Particulate Air (HEPA) filters. Generally, these tests require specific aerosols in order to get rid of the atmospheric aerosol background. Until now the principle of fluorescent aerosol concentration measuring has only allowed an integral response with a time lag by means of sampling on filters and a fluorimetric analysis after specific conditioning of these filters. 5 refs., 13 figs.

Potential radionuclide emissions from stacks on the Hanford site, Part 1: Dose assessment

Energy Technology Data Exchange (ETDEWEB)

Davis, W.E.; Barnett, J.M. [Westinghouse Hanford Company, Richland, WA (United States)

1995-02-01

On February 3, 1993, the U.S. Department of Energy, Richland Operations Office received a Compliance Order and Information Request from the Director of the Air and Toxics Division of the U.S. Environmental Protection Agency, Region 10. The Compliance Order requires RL to evaluate all radionuclide emission points at the Hanford Site to determine which are subject to continuous emission monitoring requirements in 40 CFR 61, Subpart H, and to continuously monitor radionuclide emissions in accordance with requirements in 40 CFR 61.93. The Information Request required RL to provide a written Compliance Plan to meet the requirements of the Compliance Order. A Compliance Plan was submitted to EPA, Region 10, on April 30, 1993. The Compliance Plan specified that a dose assessment would be performed for 84 Westinghouse Hanford Company stacks registered with the Washington State Department of Health on the Hanford Site. Stacks that have the potential emissions to cause an effective dose equivalent to a maximum exposed individual greater than 0.1 mrem/y must be monitored continuously for radionuclide emissions. Five methods were approved by EPA, Region 10 for performing the assessments: Release Fractions from Appendix D of 40 CFR 61, Back Calculations Using A HEPA Filtration Factor, Nondestructive Assay of HEPA Filters, A Spill Release Fraction, and Upstream of HEPA Filter Air Concentrations. The first two methods were extremely conservative for estimating releases. The third method, which used a state-of-the-art portable gamma spectrometer, yielded surprising results from the distribution of radionuclides on the HEPA filters. All five methods are described. Assessments using a HEPA Filtration Factor for back calculations identified 32 stacks that would have emissions that would cause an EDE to the MEI greater than 0.1 mrem y{sup {minus}1}. The number was reduced to 15 stacks when the other methods were applied. The paper discusses reasons for the overestimates.

Removal of iron and manganese using biological roughing up flow filtration technology.

Science.gov (United States)

Pacini, Virginia Alejandra; María Ingallinella, Ana; Sanguinetti, Graciela

2005-11-01

The removal of iron and manganese from groundwater using biological treatment methods is almost unknown in Latin America. Biological systems used in Europe are based on the process of double rapid biofiltration during which dissolved oxygen and pH need to be strictly controlled in order to limit abiotic iron oxidation. The performance of roughing filter technology in a biological treatment process for the removal of iron and manganese, without the use of chemical agents and under natural pH conditions was studied. Two pilot plants, using two different natural groundwaters, were operated with the following treatment line: aeration, up flow roughing filtration and final filtration (either slow or rapid). Iron and manganese removal efficiencies were found to be between 85% and 95%. The high solid retention capability of the roughing filter means that it is possible to remove iron and manganese simultaneously by biotic and abiotic mechanisms. This system combines simple, low-cost operation and maintenance with high iron and manganese removal efficiencies, thus constituting a technology which is particularly suited to small waterworks.

Preferential induction of the AhR gene battery in HepaRG cells after a single or repeated exposure to heterocyclic aromatic amines

International Nuclear Information System (INIS)

Dumont, Julie; Josse, Rozenn; Lambert, Carine; Antherieu, Sebastien; Laurent, Veronique; Loyer, Pascal; Robin, Marie-Anne; Guillouzo, Andre

2010-01-01

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) are two of the most common heterocyclic aromatic amines (HAA) produced during cooking of meat, fish and poultry. Both HAA produce different tumor profiles in rodents and are suspected to be carcinogenic in humans. In order to better understand the molecular basis of HAA toxicity, we have analyzed gene expression profiles in the metabolically competent human HepaRG cells using pangenomic oligonucleotide microarrays, after either a single (24-h) or a repeated (28-day) exposure to 10 μM PhIP or MeIQx. The most responsive genes to both HAA were downstream targets of the arylhydrocarbon receptor (AhR): CYP1A1 and CYP1A2 after both time points and CYP1B1 and ALDH3A1 after 28 days. Accordingly, CYP1A1/1A2 induction in HAA-treated HepaRG cells was prevented by chemical inhibition or small interference RNA-mediated down-regulation of the AhR. Consistently, HAA induced activity of the CYP1A1 promoter, which contains a consensus AhR-related xenobiotic-responsive element (XRE). In addition, several other genes exhibited both time-dependent and compound-specific expression changes with, however, a smaller magnitude than previously reported for the prototypical AhR target genes. These changes concerned genes mainly related to cell growth and proliferation, apoptosis, and cancer. In conclusion, these results identify the AhR gene battery as the preferential target of PhIP and MeIQx in HepaRG cells and further support the hypothesis that intake of HAA in diet might increase human cancer risk.

Design and Characterization of Electrospun Polyamide Nanofiber Media for Air Filtration Applications

Directory of Open Access Journals (Sweden)

Jonas Matulevicius

2014-01-01

Full Text Available Electrospun polyamide 6 (PA 6 and polyamide 6/6 (PA 6/6 nanofibers were produced in order to investigate their experimental characteristics with the goal of obtaining filtration relevant fiber media. The experimental design model of each PA nanofibers contained the following variables: polymer concentration, ratio of solvents, nanofiber media collection time, tip-to-collector distance, and the deposition voltage. The average diameter of the fibers, their morphology, basis weight, thickness, and resulting media solidity were investigated. Effects of each variable on the essential characteristics of PA 6/6 and PA 6 nanofiber media were studied. The comparative analysis of the obtained PA 6/6 and PA 6 nanofiber characteristics revealed that PA 6/6 had higher potential to be used in filtration applications. Based on the experimental results, the graphical representation—response surfaces—for obtaining nanofiber media with the desirable fiber diameter and basis weight characteristics were derived. Based on the modelling results the nanofiber filter media (mats were fabricated. Filtration results revealed that nanofiber filter media electrospun from PA6/6 8% (w/vol solutions with the smallest fiber diameters (62–66 nm had the highest filtration efficiency (PA6/6_30 = 84.9–90.9% and the highest quality factor (PA6/6_10 = 0.0486–0.0749 Pa−1.

Projective Dimension in Filtrated K-Theory

DEFF Research Database (Denmark)

Bentmann, Rasmus Moritz

2013-01-01

Under mild assumptions, we characterise modules with projective resolutions of length n∈N in the target category of filtrated K-theory over a finite topological space in terms of two conditions involving certain Tor -groups. We show that the filtrated K-theory of any separable C∗dash-algebra over...... any topological space with at most four points has projective dimension 2 or less. We observe that this implies a universal coefficient theorem for rational equivariant KK-theory over these spaces. As a contrasting example, we find a separable C∗dash-algebra in the bootstrap class over a certain five......-point space, the filtrated K-theory of which has projective dimension 3. Finally, as an application of our investigations, we exhibit Cuntz-Krieger algebras which have projective dimension 2 in filtrated K-theory over their respective primitive spectrum....

Recent developments in powder resin precoat filtration for condensate clean-up at nuclear power plants with boiling water reactors

International Nuclear Information System (INIS)

Plaisier, L.

1990-01-01

The necessity to optimize condensate clean-up by means of powder resin precoat filtration has gained more and more importance. Not only the cost of powder resins themselves is important in this regard, but even more so the disposal of used resins and replaced filter elements. The factors influencing direct filtration efficiency, resin consumption, and service life of filter elements (powder resin quality; way of preparing the water - resin mixture; precoating method; filter design and piping; type and quality of filter elements, and filtration speed) are outlined. A method designed to reduce filtration speed as much as possible, i.e. to enlarge the filter surface while maintaining its volume and avoiding adverse effects, is described in detail and substantiated by data obtained from pilot tests. (orig./BBR) [de

Inverse Problem of Air Filtration of Nanoparticles: Optimal Quality Factors of Fibrous Filters

Directory of Open Access Journals (Sweden)

Dahua Shou

2015-01-01

Full Text Available Application of nanofibers has become an emerging approach to enhance filtration efficiency, but questions arise about the decrease in Quality factor (QF for certain particles due to the rapidly increasing pressure drop. In this paper, we theoretically investigate the QF of dual-layer filters for filtration of monodisperse and polydisperse nanoparticles. The inverse problem of air filtration, as defined in this work, consists in determining the optimal construction of the two-layer fibrous filter with the maximum QF. In comparison to a single-layer substrate, improved QF values for dual-layer filters are found when a second layer with proper structural parameters is added. The influences of solidity, fiber diameter, filter thickness, face velocity, and particle size on the optimization of QF are studied. The maximum QF values for realistic polydisperse particles with a lognormal size distribution are also found. Furthermore, we propose a modified QF (MQF accounting for the effects of energy cost and flow velocity, which are significant in certain operations. The optimal MQF of the dual-layer filter is found to be over twice that of the first layer. This work provides a quick tool for designing and optimizing fibrous structures with better performance for the air filtration of specific nanoparticles.

Micron-pore-sized metallic filter tube membranes for filtration of particulates and water purification.

Science.gov (United States)

Phelps, T J; Palumbo, A V; Bischoff, B L; Miller, C J; Fagan, L A; McNeilly, M S; Judkins, R R

2008-07-01

Robust filtering techniques capable of efficiently removing particulates and biological agents from water or air suffer from plugging, poor rejuvenation, low permeance, and high backpressure. Operational characteristics of pressure-driven separations are in part controlled by the membrane pore size, charge of particulates, transmembrane pressure and the requirement for sufficient water flux to overcome fouling. With long term use filters decline in permeance due to filter-cake plugging of pores, fouling, or filter deterioration. Though metallic filter tube development at ORNL has focused almost exclusively on gas separations, a small study examined the applicability of these membranes for tangential filtering of aqueous suspensions of bacterial-sized particles. A mixture of fluorescent polystyrene microspheres ranging in size from 0.5 to 6 microm in diameter simulated microorganisms in filtration studies. Compared to a commercial filter, the ORNL 0.6 microm filter averaged approximately 10-fold greater filtration efficiency of the small particles, several-fold greater permeance after considerable use and it returned to approximately 85% of the initial flow upon backflushing versus 30% for the commercial filter. After filtering several liters of the particle-containing suspension, the ORNL composite filter still exhibited greater than 50% of its initial permeance while the commercial filter had decreased to less than 20%. When considering a greater filtration efficiency, greater permeance per unit mass, greater percentage of rejuvenation upon backflushing (up to 3-fold), and likely greater performance with extended use, the ORNL 0.6 microm filters can potentially outperform the commercial filter by factors of 100-1,000 fold.

Dual-color fluorescence imaging to monitor CYP3A4 and CYP3A7 expression in human hepatic carcinoma HepG2 and HepaRG cells.

Directory of Open Access Journals (Sweden)

Saori Tsuji

Full Text Available Human adult hepatocytes expressing CYP3A4, a major cytochrome P450 enzyme, are required for cell-based assays to evaluate the potential risk of drug-drug interactions caused by transcriptional induction of P450 enzymes in early-phase drug discovery and development. However, CYP3A7 is preferentially expressed in premature hepatoblasts and major hepatic carcinoma cell lines. The human hepatocellular carcinoma cell line HepaRG possesses a high self-renewal capacity and can differentiate into hepatic cells similar to human adult hepatocytes in vitro. Transgenic HepaRG cells, in which the expression of fluorescent reporters is regulated by 35 kb regulatory elements of CYP3A4, have a distinct advantage over human hepatocytes isolated by collagenase perfusion, which are unstable in culture. Thus, we created transgenic HepaRG and HepG2 cells by replacing the protein-coding regions of human CYP3A4 and CYP3A7 with enhanced green fluorescent protein (EGFP and DsRed reporters, respectively, in a bacterial artificial chromosome vector that included whole regulatory elements. The intensity of DsRed fluorescence was initially high during the proliferation of transgenic HepaRG cells. However, most EGFP-positive cells were derived from those in which DsRed fluorescence was extinguished. Comparative analyses in these transgenic clones showed that changes in the total fluorescence intensity of EGFP reflected fold changes in the mRNA level of endogenous CYP3A4. Moreover, CYP3A4 induction was monitored by the increase in EGFP fluorescence. Thus, this assay provides a real-time evaluation system for quality assurance of hepatic differentiation into CYP3A4-expressing cells, unfavourable CYP3A4 induction, and fluorescence-activated cell sorting-mediated enrichment of CYP3A4-expressing hepatocytes based on the total fluorescence intensities of fluorescent reporters, without the need for many time-consuming steps.

SimBa: An Efficient Tool for Approximating Rips-Filtration Persistence via Simplicial Batch-Collapse

OpenAIRE

Dey, Tamal K.; Shi, Dayu; Wang, Yusu

2016-01-01

In topological data analysis, a point cloud data P extracted from a metric space is often analyzed by computing the persistence diagram or barcodes of a sequence of Rips complexes built on $P$ indexed by a scale parameter. Unfortunately, even for input of moderate size, the size of the Rips complex may become prohibitively large as the scale parameter increases. Starting with the Sparse Rips filtration introduced by Sheehy, some existing methods aim to reduce the size of the complex so as to ...

Vibrating membrane filtration as improved technology for microalgae dewatering.

Science.gov (United States)

Nurra, Claudia; Clavero, Ester; Salvadó, Joan; Torras, Carles

2014-04-01

The effect of shear-enhanced filtration by vibratory process in microalgae dewatering is presented in this paper. The aim of this research was to investigate the technical performance and improvement of vibrating membrane filtration compared with conventional tangential cross-flow filtration in microalgae concentration. An industrial-scale available commercial set-up was used. Several membrane materials as polyethersulfone, polyacrylonitrile, etc., and mean pore sizes (from 7000Da to 0.2μm) were tested and compared in both filtration set-ups. Experiments were carried-out with Nannochloropsis gaditana and Phaeodactylum tricornutum microalgae. It has been demonstrated that, even if the choice of the membrane depends on its cut-off, its material and the type of microalgae filtrated, dynamic filtration is always the best technology over a conventional one. If with conventional filtration permeability values were in the vicinity of 10L/h/m(2)/bar in steady state phase, with dynamic filtration these values increased to 30L/h/m(2)/bar or more. Copyright © 2014 Elsevier Ltd. All rights reserved.

Chemical and microstructural analyses for heavy metals removal from water media by ceramic membrane filtration.

Science.gov (United States)

Ali, Asmaa; Ahmed, Abdelkader; Gad, Ali

2017-01-01

This study aims to investigate the ability of low cost ceramic membrane filtration in removing three common heavy metals namely; Pb 2+ , Cu 2+ , and Cd 2+ from water media. The work includes manufacturing ceramic membranes with dimensions of 15 by 15 cm and 2 cm thickness. The membranes were made from low cost materials of local clay mixed with different sawdust percentages of 0.5%, 2.0%, and 5.0%. The used clay was characterized by X-ray diffraction (XRD) and X-ray fluorescence analysis. Aqueous solutions of heavy metals were prepared in the laboratory and filtered through the ceramic membranes. The influence of the main parameters such as pH, initial driving pressure head, and concentration of heavy metals on their removal efficiency by ceramic membranes was investigated. Water samples were collected before and after the filtration process and their heavy metal concentrations were determined by chemical analysis. Moreover, a microstructural analysis using scanning electronic microscope (SEM) was performed on ceramic membranes before and after the filtration process. The chemical analysis results showed high removal efficiency up to 99% for the concerned heavy metals. SEM images approved these results by showing adsorbed metal ions on sides of the internal pores of the ceramic membranes.

Potential radionuclide emissions from stacks on the Hanford Site. Part 1: Dose assessment

International Nuclear Information System (INIS)

Davis, W.E.; Barnett, J.M.

1994-06-01

On February 3, 1993, the US Department of Energy, Richland Operations Office (RL) received a Compliance Order and Information Request from the Director of the Air and Toxics Division of the US Environmental Protection Agency (EPA), Region 10. The Compliance Plan specified that a dose assessment would be performed for 84 Westinghouse Hanford Company (WHC) stacks registered with the Washington State Department of Health (WAC 246-247) on the Hanford Site. Stacks that have the potential emissions to cause an effective dose equivalent (EDE) to a maximum exposed individual (MEI) greater than 0.1 mrem y -1 must be monitored continuously for radionuclide emissions. Five methods were approved by EPA, Region 10 for performing the assessments: Release Fractions from Appendix D of 40 CFR 61, Back Calculations Using A HEPA Filtration Factor, Nondestructive Assay of HEPA Filters, A Spill Release Fraction, and Upstream of HEPA Filter Air Concentrations. The first two methods were extremely conservative for estimating releases. The third method which used a state-of-the-art portable gamma spectrometer, yielded surprising results from the distribution of radionuclides on the HEPA filters. All five methods are described

The effect of filter cake viscoelasticity on filtration

DEFF Research Database (Denmark)

Christensen, Morten Lykkegaard

, it is difficult to use the existing mathematical filtration models to simulate and optimise the filtration process. Activated sludge as well as synthetic model particles has been filtrated in this project. The study shows that compression of the formed filter cake is a time dependent process, and not only...

40 CFR 141.71 - Criteria for avoiding filtration.

Science.gov (United States)

2010-07-01

... PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Filtration and Disinfection § 141.71 Criteria for avoiding filtration. A public water system that uses a surface water source must meet all of...)(C)(iii), that filtration is required. A public water system that uses a ground water source under...

Treatment of Wastewater From Car Washes Using Natural Coagulation and Filtration System

Science.gov (United States)

Al-Gheethi, A. A.; Mohamed, R. M. S. R.; Rahman, M. A. A.; Johari, M. R.; Kassim, A. H. M.

2016-07-01

Wastewater generated from carwash is one of the main wastewater resources, which contribute effectively in the increasing of environmental contamination due to the chemical characteristics of the car wastes. The present work aimed to develop an integrated treatment system for carwash wastewater based on coagulation and flocculation using Moringa oleifera and Ferrous Sulphate (FeSO4.7H2O) as well as natural filtration system. The carwash wastewater samples were collected from carwash station located at Parit Raja, Johor, Malaysia. The treatment system of car wash wastewater was designed in the lab scale in four stages included, aeration, coagulation and flocculation, sedimentation and filtration. The coagulation and flocculation unit was carried out using different dosage (35, 70, 105 and 140 mg L-1) of M. oleifera and FeSO4.7H2O, respectively. The efficiency of the integrated treatment system to treat carwash wastewater and to meet Environmental Quality Act (EQA 1974) was evaluated based on the analysis of pH, dissolved oxygen (DO), chemical oxygen demand (COD) and turbidity (NTU). The integrated treatment system was efficient for treatment of raw carwash wastewater. The treated carwash wastewaters meet EQA 1974 regulation 2009 (Standards A) in the term of pH and DO while, turbidity and COD reduced in the wastewater to meet Standards B. The integrated treatment system designed here with natural coagulant (M. oleifera) and filtration unit were effective for primary treatment of carwash wastewater before the final disposal or to be reused again for carwash process.

Relation Between Filtration and Soil Consolidation Theories

OpenAIRE

Strzelecki Tomasz; Strzelecki Michał

2015-01-01

This paper presents a different, than commonly used, form of equations describing the filtration of a viscous compressible fluid through a porous medium in isothermal conditions. This mathematical model is compared with the liquid flow equations used in the theory of consolidation. It is shown that the current commonly used filtration model representation significantly differs from the filtration process representation in Biot’s and Terzaghi’s soil consolidation models, which has a bearing on...

Removal of particulates from nuclear offgas

International Nuclear Information System (INIS)

Burchsted, C.A.

1976-01-01

Particulate removal from nuclear offgases can be broken down into three parts: pretreatment, prefiltration, and absolute filtration. Pretreatment, using conventional air cleaning devices in most cases, is sometimes required to temper the gases and remove heavy concentrations of particulate matter. Prefiltration, if required, serves primarily to protect the final filter stages from heavy dust loadings in order to extend their life. HEPA filters are the most commonly used ''absolute'' filtration devices and are always required for removal of submicrometer particulates that cannot be removed effectively by other devices

A simplified system for doing ICP analysis on radioactive samples

International Nuclear Information System (INIS)

McCown, J.J.

1985-11-01

Methods for setting up equipment to perform analyses on radioactive materials vary considerably from one site to another. Factors include the interests of the group involved, i.e., research vs service work; the type of building containing the lab; the arrangement of the lab for contamination control; previous experiences in operating similar equipment; the local interpretation of safety regulations; and the time and money available for the task. The Chemistry and Analysis group of the Westinghouse Hanford Company performs analytical chemistry in support of many Hanford programs. Samples analyzed cover a wide variety of materials with more than 50% involving radioactivity of one type or another. All of the laboratories in the building are connected to a common exhaust system with ductwork leading to the basement. Double HEPA filtration is provided with the first stage in the basement and the final stage done in the exhaust fan and filter building northwest of the main building. In addition, glove boxes are equipped with small HEPA filters on their outlet providing another stage of filtration. 6 figs

Development of an Indexing Media Filtration System for Long Duration Space Missions

Science.gov (United States)

Agui, Juan H.; Vijayakumar, R.

2013-01-01

The effective maintenance of air quality aboard spacecraft cabins will be vital to future human exploration missions. A key component will be the air cleaning filtration system which will need to remove a broad size range of particles derived from multiple biological and material sources. In addition, during surface missions any extraterrestrial planetary dust, including dust generated by near-by ISRU equipment, which is tracked into the habitat will also need to be managed by the filtration system inside the pressurized habitat compartments. An indexing media filter system is being developed to meet the demand for long-duration missions that will result in dramatic increases in filter service life and loading capacity, and will require minimal crew involvement. The filtration system consists of three stages: an inertial impactor stage, an indexing media stage, and a high-efficiency filter stage, packaged in a stacked modular cartridge configuration. Each stage will target a specific range of particle sizes that optimize the filtration and regeneration performance of the system. An 1/8th scale and full-scale prototype of the filter system have been fabricated and have been tested in the laboratory and reduced gravity environments that simulate conditions on spacecrafts, landers and habitats. Results from recent laboratory and reduce-gravity flight tests data will be presented. The features of the new filter system may also benefit other closed systems, such as submarines, and remote location terrestrial installations where servicing and replacement of filter units is not practical.

Salt disposition alternatives filtration at SRTC

International Nuclear Information System (INIS)

Walker, B. W.; Hobbs, D.

2000-01-01

Several of the prospective salt disposition alternative technologies require a monosodium titanate (MST) contact to remove strontium and actinides from inorganic salt solution feedstock. This feedstock also contains sludge solids from waste removal operations and may contain defoamers added in the evaporator systems. Filtration is required to remove the sludge and MST solids before sending the salt solution for further processing. This report describes testing performed using the Parallel Theological Experimental Filter (PREF). The PREF contains two single tube Mott sintered metal crossflow filters. For this test one filter was isolated so that the maximum velocities could be achieved. Previous studies showed slurries of MST and sludge in the presence of sodium tetraphenylborate (NaTPB) were filterable since the NaTPB slurry formed a filter cake which aided in removing the smaller MST and sludge particles. Some of the salt disposition alternative technologies do not use NaTPB raising the question of how effective crossflow filtration is with a feed stream containing only sludge and MST. Variables investigated included axial velocity, transmembrane pressure, defoamer effects, and solids concentration (MST and sludge). Details of the tests are outlined in the technical report WSRC-RP-98-O0691. Key conclusions from this study are: (1) Severe fouling of the Mott sintered metal filter did not occur with any of the solutions filtered. (2) The highest fluxes, in the range of .46 to 1.02 gpm/f 2 , were obtained when salt solution decanted from settled solids was fed to the filter. These fluxes would achieve 92 to 204 gpm filtrate production for the current ITP filters. The filtrate fluxes were close to the flux of 0.42 gpm/f 2 reported for In Tank Precipitation Salt Solution by Morrisey. (3) For the range of solids loading studied, the filter flux ranged from .04 to .17 gpm/f 2 which would result in a filtrate production rate of 9 to 31 gpm for the current HP filter. (4

Noble gas control room accident filtration system for severe accident conditions N-CRAFT. System design

International Nuclear Information System (INIS)

Hill, Axel

2014-01-01

Severe accidents might cause the release of airborne radioactive substances to the environment of the NPP. This can either be due to leakages of the containment or due to a filtered containment venting in order to ensure the overall integrity of the containment. During the containment venting process aerosols and iodine can be retained by the FCVS which prevents long term ground contamination. Noble gases are not retainable by the FCVS. From this it follows that a large amount of radioactive noble gases (e.g. xenon, krypton) might be present in the nearby environment of the plant dominating the activity release, depending on the venting procedure and the weather conditions. Accident management measures are necessary in case of severe accidents and the prolonged stay of staff inside the main control room (MCR) or emergency response center (ERC) is essential. Therefore, the in leakage and contamination of the MRC and ERC with airborne activity has to be prevented. The radiation exposure of the crises team needs to be minimized. The entrance of noble gases cannot be sufficiently prevented by the conventional air filtration systems such as HEPA filters and iodine absorbers. With the objective to prevent an unacceptable contamination of the MCR/ERC atmosphere by noble gases AREVA GmbH has developed a noble gas retention system. The noble gas control room accident filtration system CRAFT is designed for this case and provides supply of fresh air to the MCR/ERC without time limitation. The retention process of the system is based on the dynamic adsorption of noble gases on activated carbon. The system consists of delay lines (carbon columns) which are operated by a continuous and simultaneous adsorption and desorption process. These cycles ensure a periodic load and flushing of the delay lines retaining the noble gases from entering the MCR. CRAFT allows a minimization of the dose rate inside MCR/ERC and ensures a low radiation exposure to the staff on shift maintaining

Filtration Systems Design for Universal Oils in Agricultural Tractors

Directory of Open Access Journals (Sweden)

R. Majdan

2017-12-01

Full Text Available Three filtration systems using the tractor hydraulic circuit were proposed and verified during the tractors operation. Using the tractor-implement hydraulic system and filter body with accessories the universally useful filtration systems were designed. The designed filtration systems are the second stage of universal oil filtration whereas the first stage is the standard tractor filter. The decrease in the content of iron reached the values 25.53 %, 32.95 % and 41.55 % and the average decrease in oil contamination characterized by average value of decrease in content of iron, copper and silicium reached values 24.3 %, 24.7 % and 35.53 % in dependence on the filtration system and an oil contamination level. The decrease in contamination level verified the ability of designed filtration systems for agricultural tractors.

DQE of wireless digital detectors: Comparative performance with differing filtration schemes

Energy Technology Data Exchange (ETDEWEB)

Samei, Ehsan [Carl E. Ravin Advanced Imaging Laboratories, Departments of Radiology, Biomedical Engineering, Physics, and Electrical and Computer Engineering, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27705 (United States); Murphy, Simon; Christianson, Olav [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States)

2013-08-15

Purpose: Wireless flat panel detectors are gaining increased usage in portable medical imaging. Two such detectors were evaluated and compared with a conventional flat-panel detector using the formalism of the International Electrotechnical Commission (IEC 62220-1) for measuring modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE) using two different filtration schemes.Methods: Raw images were acquired for three image receptors (DRX-1C and DRX-1, Carestream Health; Inc., Pixium 4600, Trixell) using a radiographic system with a well-characterized output (Philips Super80 CP, Philips Healthcare). Free in-air exposures were measured using a calibrated radiation meter (Unfors Mult-O-Meter Type 407, Unfors Instruments AB). Additional aluminum filtration and a new alternative combined copper-aluminum filtration were used to conform the x ray output to IEC-specified beam quality definitions RQA5 and RQA9. Using the IEC 62220-1 formalism, each detector was evaluated at X{sub N}/2, X{sub N}, and 2X{sub N}, where the normal exposure level to the detector surface (X{sub N}) was set to 8.73 μGy (1.0 mR). The prescribed edge test device was used to evaluate the MTF, while the NNPS was measured using uniform images. The DQE was then calculated from the MTF and NNPS and compared across detectors, exposures, and filtration schemes.Results: The three DR systems had largely comparable MTFs with DRX-1 demonstrating lower values above 1.0 cycles/mm. At each exposure, DRX-1C and Pixium detectors demonstrated better noise performance than that of DRX-1. Zero-frequency DQEs for DRX-1C, Pixium, and DRX-1 detectors were approximately 74%, 63%, and 38% for RQA5 and 50%, 42%, and 28% for RQA9, respectively.Conclusions: DRX-1C detector exhibited superior DQE performance compared to Pixium and DRX-1. In terms of filtration, the alternative filtration was found to provide comparable performance in terms of rank ordering of different

DUST FILTRATION BY PLANET-INDUCED GAP EDGES: IMPLICATIONS FOR TRANSITIONAL DISKS

Energy Technology Data Exchange (ETDEWEB)

Zhu Zhaohuan; Dong Ruobing [Department of Astrophysical Sciences, 4 Ivy Lane, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Nelson, Richard P. [Astronomy Unit, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Espaillat, Catherine [Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Hartmann, Lee, E-mail: zhzhu@astro.princeton.edu, E-mail: rdong@astro.princeton.edu, E-mail: lhartm@umich.edu, E-mail: r.p.nelson@qmul.ac.uk, E-mail: cespaillat@cfa.harvard.edu [Department of Astronomy, University of Michigan, 500 Church St., Ann Arbor, MI 48109 (United States)

2012-08-10

By carrying out two-dimensional two-fluid global simulations, we have studied the response of dust to gap formation by a single planet in the gaseous component of a protoplanetary disk-the so-called dust filtration mechanism. We have found that a gap opened by a giant planet at 20 AU in an {alpha} = 0.01, M-dot =10{sup -8} M{sub Sun} yr{sup -1} disk can effectively stop dust particles larger than 0.1 mm drifting inward, leaving a submillimeter (submm) dust cavity/hole. However, smaller particles are difficult to filter by a gap induced by a several M{sub J} planet due to (1) dust diffusion and (2) a high gas accretion velocity at the gap edge. Based on these simulations, an analytic model is derived to understand what size particles can be filtered by the planet-induced gap edge. We show that a dimensionless parameter T{sub s} /{alpha}, which is the ratio between the dimensionless dust stopping time and the disk viscosity parameter, is important for the dust filtration process. Finally, with our updated understanding of dust filtration, we have computed Monte Carlo radiative transfer models with variable dust size distributions to generate the spectral energy distributions of disks with gaps. By comparing with transitional disk observations (e.g., GM Aur), we have found that dust filtration alone has difficulties depleting small particles sufficiently to explain the near-IR deficit of moderate M-dot transitional disks, except under some extreme circumstances. The scenario of gap opening by multiple planets studied previously suffers the same difficulty. One possible solution is to invoke both dust filtration and dust growth in the inner disk. In this scenario, a planet-induced gap filters large dust particles in the disk, and the remaining small dust particles passing to the inner disk can grow efficiently without replenishment from fragmentation of large grains. Predictions for ALMA have also been made based on all these scenarios. We conclude that dust filtration

DUST FILTRATION BY PLANET-INDUCED GAP EDGES: IMPLICATIONS FOR TRANSITIONAL DISKS

International Nuclear Information System (INIS)

Zhu Zhaohuan; Dong Ruobing; Nelson, Richard P.; Espaillat, Catherine; Hartmann, Lee

2012-01-01

By carrying out two-dimensional two-fluid global simulations, we have studied the response of dust to gap formation by a single planet in the gaseous component of a protoplanetary disk—the so-called dust filtration mechanism. We have found that a gap opened by a giant planet at 20 AU in an α = 0.01, M-dot =10 -8 M ☉ yr -1 disk can effectively stop dust particles larger than 0.1 mm drifting inward, leaving a submillimeter (submm) dust cavity/hole. However, smaller particles are difficult to filter by a gap induced by a several M J planet due to (1) dust diffusion and (2) a high gas accretion velocity at the gap edge. Based on these simulations, an analytic model is derived to understand what size particles can be filtered by the planet-induced gap edge. We show that a dimensionless parameter T s /α, which is the ratio between the dimensionless dust stopping time and the disk viscosity parameter, is important for the dust filtration process. Finally, with our updated understanding of dust filtration, we have computed Monte Carlo radiative transfer models with variable dust size distributions to generate the spectral energy distributions of disks with gaps. By comparing with transitional disk observations (e.g., GM Aur), we have found that dust filtration alone has difficulties depleting small particles sufficiently to explain the near-IR deficit of moderate M-dot transitional disks, except under some extreme circumstances. The scenario of gap opening by multiple planets studied previously suffers the same difficulty. One possible solution is to invoke both dust filtration and dust growth in the inner disk. In this scenario, a planet-induced gap filters large dust particles in the disk, and the remaining small dust particles passing to the inner disk can grow efficiently without replenishment from fragmentation of large grains. Predictions for ALMA have also been made based on all these scenarios. We conclude that dust filtration with planet(s) in the disk is a

Filtration of aerosols produced by a sodium fire

International Nuclear Information System (INIS)

Duverger de Cuy, G.; Colome, J.

1977-01-01

The containment system of the Super Phenix reactor takes account of the possibility of contaminated sodium fires, particularly in the vicinity of the fuel storage drum. It is thus necessary to contain the emitted radioactivity associated with a quantity of sodium aerosols of the order of some 10 g/m 3 . Investigations previously carried out had shown that the retention capacity of high-efficiency asbestos filters was clearly insufficient. A new research programme on the filtration of sodium aerosols has thus been worked out with the aim of: gaining a better understanding of the granulometry of the aerosols produced by the fire; checking the efficiency of the new glass-fibre media of which high-efficiency filters are composed; selecting a prefiltering system which, in conjunction with the high-efficiency filter, would ensure a suitable retention capacity for the whole unit. The following prefilters are under investigation: agglomerating cyclones; fabric prefilters (dense filter media - variable density filters - bag filters); water prefilters; sand prefilters. The experimental equipment on which this programme has been based is presented. Results have so far been obtained for agglomerating cyclones (recirculating loop with a cyclone of 95% efficiency), for a number of textile prefilters and for the retention capacity of high-efficiency filters

Public health protection through bank filtration - Kearney Nebraska case study

Science.gov (United States)

Esseks, E.; Bellamy, W.; Heinemann, T.; Stocker, K.

2003-04-01

results of an additional 12-month study. Additional monitoring took place from October 1997 to October 1998. Results of the second study supported the findings of the original 18-week study. The Department finalized approval of the removal credits on December 16, 1999. This paper discusses the 2 studies, ongoing monitoring, decisions made by the Department, and issues the City and the Department have addressed and will be addressing with the addition of new treatment requirements to surface water treatment rules. In addition, this paper examines features of the Island wellfield that may explain the documented bank filtration treatment efficiencies.

Resistance of HEPA filter separator materials to humid air--hydrogen fluoride--fluorine environments

International Nuclear Information System (INIS)

Weber, C.W.; Petit, G.S.; Woodfin, S.B.

1977-01-01

The U. S. Energy Research and Development Administration (ERDA) is interested in the development of a high-efficiency particulate air (HEPA) filter that is resistant to such corrosive reagents as hydrogen fluoride (HF) and fluorine (F 2 ) in air environments of normal relative humidity (about 50% RH). Several types of separator materials are used in the fabrication of commercial filters. The basic types of separator materials are asbestos, Kraft paper, plastic, and aluminum. At the request of the ERDA Division of Operational Safety, the different types of separator materials have been evaluated for their resistance to corrosive attack by HF and F 2 . The separator materials were dynamically tested in the 4-stage multiunit tester located in the Oak Ridge Gaseous Diffusion Plant laboratories. This is the system previously used in the evaluation of the Herty Foundation filter paper samples. Concurrent with the testing of filter media for its resistance to HF and F 2 , another component of the completed filter, the separator, was tested. All samples were exposed to a constant air flow (50% RH) of 32 liters/min, at 100 0 F, containing 900 ppM HF and 300 ppM F 2 . Exposure periods varied from 2 to 1000 h; however, the longer exposures were made only on the stronger candidates. Test results show the plastic and aluminum separator materials to be superior to the other types in resistance to HF and F 2 . The asbestos separators disintegrated after a relatively short exposure time; the Kraft paper types were the next weakest. The Clear Plastic S was the best performer of the plastics tested

Determination of chromate ion in drilling mud filtrates

International Nuclear Information System (INIS)

Whitfill, D.

1980-01-01

A method of determining the amount of chromate ion in an aqueous drilling mud filtrate containing organic color bodies such as lignosulfate wherein the method comprises: (A) treating the aqueous filtrate with an effective amount of hydrogen peroxide to destroy said color bodies, and (B) measuring the amount of chromate ion in the filtrate by means of a spectrophotometer

Filtration of Sludge and Sodium Nonatitanate Solutions

International Nuclear Information System (INIS)

Poirier, M.R.

2000-01-01

The proposed facility designs for the ion exchange and solvent extraction flowsheets under development to treat high level waste at the Savannah River Site use crossflow filtration to remove entrained sludge and monosodium titanate (MST). Bench-scale and pilot-scale testing performed with simulated feed streams showed much lower filtration rates than desired for the process. This report documents an investigation of the impact on filtration of using Honeywell sodium nonatitanate (ST), rather than MST, for strontium and actinide removal

The Perspective of Riverbank Filtration in China

Science.gov (United States)

Li, J.; Teng, Y.; Zhai, Y.; Zuo, R.

2014-12-01

Sustainable drinking water supply can affect the health of people, and the surrounding ecosystems. According to statistics of the monitoring program of drinking water sources in 309 at or above prefecture level of China in 2013, the major pollutants index were total phosphorus, ammonia and manganese in surface drinking water sources, respectively, iron, ammonia and manganese in groundwater drinking water sources, respectively. More than 150 drinking water emergency environmental accidents happened since 2006, 52 of these accidents led to the disruption of water supply in waterworks, and a population of over ten million were affected. It indicated that there is a potential risk for people's health by the use of river water directly and it is necessary to require alternative techniques such as riverbank filtration for improving the drinking water quality. Riverbank filtration is an inexpensive natural process, not only smoothing out normal pollutant concentration found in surface water but also significantly reducing the risk from such emergency events as chemical spill into the river. Riverbank filtration technique has been used in many countries more than 100 years, including China. In China, in 1950s, the bank infiltration technique was first applied in northeast of China. Extensive bank infiltration application was conducted in 1980s, and more than 300 drinking water sources utilities bank infiltration established mainly near the Songhua River Basin, the Yellow River Basin, Haihe River Basin. However, the comparative lack of application and researches on riverbank filtration have formed critical scientific data gap in China. As the performance of riverbank filtration technique depend on not only the design and setting such as well type, pumping rate, but also the local hydrogeology and environmental properties. We recommend more riverbank filtration project and studies to be conducted to collect related significant environmental geology data in China

High efficiency particulate removal with sintered metal filters

International Nuclear Information System (INIS)

Kirstein, B.E.; Paplawsky, W.J.; Pence, D.T.; Hedahl, T.G.

1981-01-01

Because of their particle removal efficiencies and durability, sintered metal filters have been chosen for HEPA filter protection in the off-gas treatment system for the proposed Idaho National Engineering Laboratory Transuranic Waste Treatment Facility. Process evaluation of sintered metal filters indicated a lack of sufficient process design data to assume trouble-free operation. Subsequent pilot-scale testing was performed with fly ash as the test particulate. The test results showed that the sintered metal filters can have an efficiency greater than 0.9999999 for the specific test conditions used. Stable pressure drop characteristics were observed in pulsed and reversed flow blowback modes of operation. Over 4900 hours of operation were obtained with operating conditions ranging up to approximately 90 0 C and 24 volume percent water vapor in the gas stream

Filtration efficiency of an electrostatic fibrous filter: Studying filtration dependency on ultrafine particle exposure and composition

DEFF Research Database (Denmark)

Ardkapan, Siamak Rahimi; Johnson, Matthew S.; Yazdi, Sadegh

2014-01-01

The objective of the present study is to investigate the relationship between ultrafine particle concentrations and removal efficiencies for an electrostatic fibrous filter in a laboratory environment. Electrostatic fibrous filters capture particles efficiently, with a low pressure drop. Therefor...

Hanford underground storage tank waste filtration process evaluation

International Nuclear Information System (INIS)

Walker, B.W.; McCabe, D.J.

1997-01-01

The purpose of this filter study was to evaluate cross-flow filtration as effective solid-liquid separation technology for treating Hanford wastes, outline operating conditions for equipment, examine the expected filter flow rates, and determine proper cleaning. Two Hanford waste processing applications have been identified as candidates for the use of cross-flow filtration. The first of the Hanford applications involves filtration of the decanted supernate from sludge leaching and washing operations. This process involves the concentration and removal of dilute (0.05 wt percent) fines from the bulk of the supernate. The second application involves filtration to wash and concentrate the sludge during out-of-tank processing. This process employs a relatively concentrated (8 wt percent) solids feed stream. Filter studies were conducted with simulants to evaluate whether 0.5 micron cross-flow sintered metal Mott filters and 0.1 micron cross-flow Graver filters can perform solid-liquid separation of the solid/liquid waste streams effectively. In cross-flow filtration the fluid to be filtered flows in parallel to the membrane surface and generates shearing forces and/or turbulence across the filter medium. This shearing influences formation of filter cake stabilizing the filtrate flow rate

Spontaneous water filtration of bio-inspired membrane

Science.gov (United States)

Kim, Kiwoong; Kim, Hyejeong; Lee, Sang Joon

2016-11-01

Water is one of the most important elements for plants, because it is essential for various metabolic activities. Thus, water management systems of vascular plants, such as water collection and water filtration have been optimized through a long history. In this view point, bio-inspired technologies can be developed by mimicking the nature's strategies for the survival of the fittest. However, most of the underlying biophysical features of the optimized water management systems remain unsolved In this study, the biophysical characteristics of water filtration phenomena in the roots of mangrove are experimentally investigated. To understand water-filtration features of the mangrove, the morphological structures of its roots are analyzed. The electrokinetic properties of the root surface are also examined. Based on the quantitatively analyzed information, filtration of sodium ions in the roots are visualized. Motivated by this mechanism, spontaneous desalination mechanism in the root of mangrove is proposed by combining the electrokinetics and hydrodynamic transportation of ions. This study would be helpful for understanding the water-filtration mechanism of the roots of mangrove and developing a new bio-inspired desalination technology. This research was financially supported by the National Research Foundation (NRF) of Korea (Contract Grant Number: 2008-0061991).

Detection and removal of impurities in nitric oxide generated from air by pulsed electrical discharge.

Science.gov (United States)

Yu, Binglan; Blaesi, Aron H; Casey, Noel; Raykhtsaum, Grigory; Zazzeron, Luca; Jones, Rosemary; Morrese, Alexander; Dobrynin, Danil; Malhotra, Rajeev; Bloch, Donald B; Goldstein, Lee E; Zapol, Warren M

2016-11-30

Inhalation of nitric oxide (NO) produces selective pulmonary vasodilation without dilating the systemic circulation. However, the current NO/N 2 cylinder delivery system is cumbersome and expensive. We developed a lightweight, portable, and economical device to generate NO from air by pulsed electrical discharge. The objective of this study was to investigate and optimize the purity and safety of NO generated by this device. By using low temperature streamer discharges in the plasma generator, we produced therapeutic levels of NO with very low levels of nitrogen dioxide (NO 2 ) and ozone. Despite the low temperature, spark generation eroded the surface of the electrodes, contaminating the gas stream with metal particles. During prolonged NO generation there was gradual loss of the iridium high-voltage tip (-90 μg/day) and the platinum-nickel ground electrode (-55 μg/day). Metal particles released from the electrodes were trapped by a high-efficiency particulate air (HEPA) filter. Quadrupole mass spectroscopy measurements of effluent gas during plasma NO generation showed that a single HEPA filter removed all of the metal particles. Mice were exposed to breathing 50 parts per million of electrically generated NO in air for 28 days with only a scavenger and no HEPA filter; the mice did not develop pulmonary inflammation or structural changes and iridium and platinum particles were not detected in the lungs of these mice. In conclusion, an electric plasma generator produced therapeutic levels of NO from air; scavenging and filtration effectively eliminated metallic impurities from the effluent gas. Copyright © 2016 Elsevier Inc. All rights reserved.

The Effect of Ventilation, Filtration and Passive Sorption on Indoor Air Quality in Museum Storage Rooms

DEFF Research Database (Denmark)

Ryhl-Svendsen, M.; Clausen, Geo

2009-01-01

in reducing nitrogen dioxide. Increased ventilation rates were expected to dilute internally generated pollutants, but ambiguous results imply that the emission rate of organic acids may also vary Recirculation/filtration was generally, the most efficient method. A cautious conclusion is that a combination...

Development of a portable sodium fluorescence aerosol generator model

CERN Document Server

LiuQun; Gao Xiao Mei; Jia Ming; Guo Chuang Cheng; Wu Tao; Liu Zhao Feng; Qiu Dan Gui

2002-01-01

A portable sodium fluorescence aerosol generator has been developed. It is a key equipment for in-situ testing of HEPA filters using sodium fluorescence method. The structure and technical specifications of the model generator are presented, along with its performance testing methods. The performance comparison result of the model with two French-made generators is also presented. The self-made generator has performances as follows: the average mass generating rate is 32.9 mg/h, mass median diameter of the particles 0.22 mu m and geometric standard deviation 1.58. The filtration efficiency up to 99.99% can be achieved flow-rate of ventilation system is less than 150000 m sup 3 /h. The portable model weight 25 kg, which is convenient for in situ testing

Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house

Energy Technology Data Exchange (ETDEWEB)

Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Delp, William W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Black, Douglas R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-12-01

This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250m downwind of the I-80 freeway in Sacramento, California. Systems were evaluated for reducing indoor concentrations of outdoor particles in summer and fall/winter, ozone in summer, and particles from stir-fry cooking. Air exchange rate was measured continuously. Energy use was estimated for year-round operation in California. Exhaust ventilation without enhanced filtration produced indoor PM_2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection whereas supply MERV16 filtration reduced PM_2.55 by 97-98% relative to outdoors. Supply filtration systems used little energy but provided no benefits for indoor-generated particles. Systems with MERV13-16 filters in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM_2.5 by 93-98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM_2.5. Indoor ozone was 3-4% of outdoors for all systems except an electronic air cleaner that produced ozone. Filtration via the FAU or portable filtration units lowered PM_2.5 by 25-75% when operated over the hour following cooking. The energy for year-round operation of FAU filtration with an efficient blower motor was estimated at 600 kWh/year.

Transport of micropollutants in a riverbank filtration system

Science.gov (United States)

van Driezum, Inge; Oudega, Thomas; Reiner, Philipp; Zessner, Matthias; Farnleitner, Andreas; Blaschke, Paul

2014-05-01

Groundwater locations at alluvial backwaters are essential for public water supply. Riverbank filtration (RBF) systems are widely used as a means of obtaining public water supplies. Riverbank filtration is an effective way to remove micropollutants from the receiving surface water. The efficiency of the RBF system strongly depends on the residence time of the water in the aquifer and on the soil properties (Ray, 2011). In order to understand all bio- and geochemical processes within the hyporheic zone (e.g. the region were mixing of surface water and groundwater occurs), exchange rates and flow patterns need to be quantified. The main study area covers the porous groundwater aquifer study site (PGWA) - an urban floodplain extending on the left bank of the River Danube downstream of the City of Vienna. It is one of the main groundwater bodies in Austria. Groundwater quality in the PGWA is influenced by a combination of anthropogenic activities, industry, wastewater treatment plants, heavy precipitation events and floodings. The upper layer of the DPA is impermeable, preventing pollution originating from the surface. The upper layer consists of silt. The underlying confined aquifer consists of sand and gravel layers. Hydraulic conductivities range from 5 x 10-2 m/s up to 5 x 10-5 m/s. Underneath the aquifer are alternating sand an clay/silt layers. Samples are taken from two transects in the DPA. These transects consist of four piezometers in the first few meters of the groundwater aquifer. Several other piezometers are placed downstream from the river-groundwater interface. The behaviour of the micropollutants in the hyporheic zone can therefore be studied intensively. The transport behaviour of several micropollutants is modeled using carbamazepine (CBZ) and acesulfame (ACE) as natural tracers. Furthermore, temperature and electrical conductivity data was used for modeling. The micropollutants are measured using an in house developed online SPE-HPLC-MS/MS method

40 CFR 141.717 - Pre-filtration treatment toolbox components.

Science.gov (United States)

2010-07-01

... surface water or GWUDI source. (c) Bank filtration. Systems receive Cryptosporidium treatment credit for... paragraph. Systems using bank filtration when they begin source water monitoring under § 141.701(a) must... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Pre-filtration treatment toolbox...

Use of a tangential filtration unit for processing liquid waste from nuclear laundries

International Nuclear Information System (INIS)

Augustin, X.; Buzonniere, A. de; Barnier, H.

1993-01-01

Nuclear laundries produce large quantities of weakly contaminated effluents charged with insoluble and soluble products. In collaboration with CEA, TECHNICATOME has developed an ultrafiltration process for liquid waste from nuclear laundries, associated with prior in-solubilization of the radiochemical activity. This process 'seeded ultrafiltration' is based on the use of decloggable mineral filter media and combines very high separation efficiency with long membrane life. The efficiency of the tangential filtration unit which has been processing effluents from the Cadarache Nuclear Research Center (CEA-France) nuclear laundry since mid-1988, has been confirmed on several sites

Dynamic optimization of dead-end membrane filtration

NARCIS (Netherlands)

Blankert, B.; Betlem, Bernardus H.L.; Roffel, B.; Marquardt, Wolfgang; Pantelides, Costas

2006-01-01

An operating strategy aimed at minimizing the energy consumption during the filtration phase of dead-end membrane filtration has been formulated. A method allowing fast calculation of trajectories is used to allow incorporation in a hierarchical optimization scheme. The optimal trajectory can be

Assessment of microbiological air quality in hemato-oncology units and its relationship with the occurrence of invasive fungal infections: an integrative review

Directory of Open Access Journals (Sweden)

Mayra Goncalves Menegueti

2013-07-01

Full Text Available Worldwide aging of the human population has promoted an increase in the incidence of neoplasia, including hematological cancers, which render patients particularly vulnerable to invasive fungal infections. For this reason, air filtration in hemato-oncology units has been recommended. However, scarce literature has assessed the impact of microbiological air quality on the occurrence of fungal infections in this population. We performed an integrative review of studies in the MEDLINE database that were published between January 1980 and October 2012, using the following combinations of keywords: air × quality × HEPA, air × quality × hematology, and airborne fungal infections. The search yielded only 13 articles, suggesting that high-efficiency filtering of the ambient air in hemato-oncology units can prevent the incidence of invasive fungal infections. However, no randomized clinical trial was found to confirm this suggestion. Currently, there is no consensus about the maximum allowable count of fungi in the air, which complicates filtration monitoring, including filter maintenance and replacement, and needs to be addressed in future studies.

Study on the Metal Fiber Filter Modeling for Capturing Radioactive Aerosol

Energy Technology Data Exchange (ETDEWEB)

Lee, Seunguk; Lee, Chanhyun; Park, Minchan; Lee, Jaekeun [EcoEnergy Research Institute, Busan (Korea, Republic of)

2015-05-15

The components of air cleaning system are demisters to remove entrained moisture, pre-filters to remove the bulk of the particulate matter, high efficiency particulate air (HEPA) filters, iodine absorbers(generally, activated carbon) and HEPA filters after the absorbers for redundancy and collection of carbon fines. The HEPA filters are most important components to prevent radioactive aerosols from being released to control room and adjacent environment. The Conventional HEPA filter has pleated media for low pressure drop. Consequently, the filters must provide high collection efficiency as well as low pressure drop. Unfortunately, conventional HEPA filters are made of glass fiber and polyester, and pose disposal issues since they cannot be recycled. In fact, 31,055 HEPA filters used in nuclear facilities in the U.S are annually disposed. The Analyses at face velocities 1cm/s and 10cm/s are also carried out, and they also show R2 value of 0.995. However, since official HEPA filter standards are established at face velocity of 5cm/s, this value will be used in further analysis. From the comparative studies carried out at different filter thickness and face velocities, a good correlation is found between the model and the experiment.

How the nuclear industry keeps it gases clean

International Nuclear Information System (INIS)

Anon.

1985-01-01

The paper surveys briefly the papers presented at a conference on gas filtration in the nuclear industry. The theory, development, design, use (under various conditions of temperature, humidity, corrosion), performance, cleaning and testing of fibrous, HEPA, metal, packed bed and magnetic filters are included, and the problems, advantages and disadvantages of the various types of filter are discussed. (U.K.)

Hazards control progress report No. 55, July through December 1977

International Nuclear Information System (INIS)

1978-01-01

Progress is reported on environmental protection and enhanced filtration studies. Environmental protection studies emphasized on-line x-ray fluorescence analysis of transition metals in waste water. Enhanced filtration studies included the following: expansion of test facility; cost-benefit analysis of placing prefilters before HEPA filters; effect of fiber-size distribution on filter pressure drop; and experimental and theoretical studies on filter loading. The following technical notes are included: data retrieval program for the whole body counter; hydrogen cyanide sorption by acid-gas respirator cartridges; glove permeation study; fire safety evaluation of boron-loaded polymer; and high-explosive shipping container studies

A new look at the economic disposal of contaminated aerosol filters

International Nuclear Information System (INIS)

Sinhuber, D.; Stiehl, H.H.; Schroth, W.

1977-01-01

HEPA filter elements loaded with radioactive aerosols represent a large percentage of the radioactive waste of nuclear plants. The HEPA filter elements used at present in air filter units are not suitable to an economic disposal and space-saving final storage on account of their construction. New concepts for HEPA filters are necessary from the point of view of waste disposal. The criteria of these new designs are as follows: reduction of space required for HEPA filters used at the same or even increased flow rates and with the same efficiency; essentially smaller dimensions of HEPA filters for storage in waste containers; removal without contamination, volume reduction (without contamination) for disposal of the HEPA filters; smallest possible volume of the HEPA filters after processing for final storage. The construction of HEPA filters as a result of the requirements mentioned above and taking into consideration the present stage of technology is explained. The advantages of such construction with regard to the criteria mentioned before are presented in comparison with the HEPA filters at present in use

Wind Turbine Gearbox Oil Filtration and Condition Monitoring

Energy Technology Data Exchange (ETDEWEB)

Sheng, Shuangwen

2015-10-25

This is an invited presentation for a pre-conference workshop, titled advances and opportunities in lubrication: wind turbine, at the 2015 Society of Tribologists and Lubrication Engineers (STLE) Tribology Frontiers Conference held in Denver, CO. It gives a brief overview of wind turbine gearbox oil filtration and condition monitoring by highlighting typical industry practices and challenges. The presentation starts with an introduction by covering recent growth of global wind industry, reliability challenges, benefits of oil filtration and condition monitoring, and financial incentives to conduct wind operation and maintenance research, which includes gearbox oil filtration and condition monitoring work presented herein. Then, the presentation moves on to oil filtration by stressing the benefits of filtration, discussing typical main- and offline-loop practices, highlighting important factors considered when specifying a filtration system, and illustrating real-world application challenges through a cold-start example. In the next section on oil condition monitoring, a discussion on oil sample analysis, oil debris monitoring, oil cleanliness measurements and filter analysis is given based on testing results mostly obtained by and at NREL, and by pointing out a few challenges with oil sample analysis. The presentation concludes with a brief touch on future research and development (R and D) opportunities. It is hoping that the information presented can inform the STLE community to start or redirect their R and D work to help the wind industry advance.

Life Support Filtration System Trade Study for Deep Space Missions

Science.gov (United States)

Agui, Juan H.; Perry, Jay L.

2017-01-01

The National Aeronautics and Space Administrations (NASA) technical developments for highly reliable life support systems aim to maximize the viability of long duration deep space missions. Among the life support system functions, airborne particulate matter filtration is a significant driver of launch mass because of the large geometry required to provide adequate filtration performance and because of the number of replacement filters needed to a sustain a mission. A trade analysis incorporating various launch, operational and maintenance parameters was conducted to investigate the trade-offs between the various particulate matter filtration configurations. In addition to typical launch parameters such as mass, volume and power, the amount of crew time dedicated to system maintenance becomes an increasingly crucial factor for long duration missions. The trade analysis evaluated these parameters for conventional particulate matter filtration technologies and a new multi-stage particulate matter filtration system under development by NASAs Glenn Research Center. The multi-stage filtration system features modular components that allow for physical configuration flexibility. Specifically, the filtration system components can be configured in distributed, centralized, and hybrid physical layouts that can result in considerable mass savings compared to conventional particulate matter filtration technologies. The trade analysis results are presented and implications for future transit and surface missions are discussed.

Dynamic optimization of a dead-end filtration trajectory: Blocking filtration laws

NARCIS (Netherlands)

Blankert, B.; Betlem, Bernardus H.L.; Roffel, B.

2006-01-01

An operating model for dead-end membrane filtration is proposed based on the well-known blocking laws. The resulting model contains three parameters representing, the operating strategy, the fouling mechanism and the fouling potential of the feed. The optimal control strategy is determined by

Inhomogeneous electric field air cleaner

International Nuclear Information System (INIS)

Schuster, B.G.

1976-01-01

For applications requiring the filtration of air contaminated with enriched uranium, plutonium or other transuranium compounds, it appears desirable to collect the material in a fashion more amenable to recovery than is now practical when material is collected on HEPA filters. In some instances, it may also be desirable to use an air cleaner of this type to substantially reduce the loading to which HEPA filters are subjected. A theoretical evaluation of such an air cleaner considers the interaction between an electrically neutral particle, dielectric or conducting, with an inhomogeneous electric field. An expression is derived for the force exerted on a particle in an electrode configuration of two concentric cylinders. Equations of motion are obtained for a particle suspended in a laminar flow of air passing through this geometry. An electrical quadrupole geometry is also examined and shown to be inferior to the cylindrical one. The results of two separate configurations of the single cell prototypes of the proposed air cleaner are described. These tests were designed to evaluate collection efficiencies using mono-disperse polystyrene latex and polydisperse NaCl aerosols. The advantages and problems of such systems in terms of a large scale air cleaning facility will be discussed

A study of dynamic filtration; Um estudo sobre filtracao dinamica

Energy Technology Data Exchange (ETDEWEB)

Girao, Joaquim Helder S [PETROBRAS, Natal, RN (Brazil). Distrito de Perfuracao da Bacia Potiguar. Div. de Tecnicas de Perfuracao

1990-12-31

The problems that cause cost increase such as: formation damage and borehole swelling or caving lead us to study the filtration of the liquid part of formation drilling fluid. With the aim of comparing static and dynamic filtration rates, we developed a modest dynamic filtration equipment, consisting of a modified API filter, connected to reservoir by means of a positive injection pump. We carried out various tests, and the results were set in charts and tables. Through these, it is possible to notice how the static and dynamic filtration curves come apart for a same pressure value. We also evaluated the effects of circulation speed, starch concentration and counter pressure. This paper does not include calculations or mathematical models accounting for filtrate invasion radii, but it demonstrates, for example, that cleaning circulation will cause lower filtration rates at lower flows. (author) 5 refs., 11 figs., 14 tabs.

A study of dynamic filtration; Um estudo sobre filtracao dinamica

Energy Technology Data Exchange (ETDEWEB)

Girao, Joaquim Helder S. [PETROBRAS, Natal, RN (Brazil). Distrito de Perfuracao da Bacia Potiguar. Div. de Tecnicas de Perfuracao

1989-12-31

The problems that cause cost increase such as: formation damage and borehole swelling or caving lead us to study the filtration of the liquid part of formation drilling fluid. With the aim of comparing static and dynamic filtration rates, we developed a modest dynamic filtration equipment, consisting of a modified API filter, connected to reservoir by means of a positive injection pump. We carried out various tests, and the results were set in charts and tables. Through these, it is possible to notice how the static and dynamic filtration curves come apart for a same pressure value. We also evaluated the effects of circulation speed, starch concentration and counter pressure. This paper does not include calculations or mathematical models accounting for filtrate invasion radii, but it demonstrates, for example, that cleaning circulation will cause lower filtration rates at lower flows. (author) 5 refs., 11 figs., 14 tabs.

Prediction of the filtrate particle size distribution from the pore size distribution in membrane filtration: Numerical correlations from computer simulations

Science.gov (United States)

Marrufo-Hernández, Norma Alejandra; Hernández-Guerrero, Maribel; Nápoles-Duarte, José Manuel; Palomares-Báez, Juan Pedro; Chávez-Rojo, Marco Antonio

2018-03-01

We present a computational model that describes the diffusion of a hard spheres colloidal fluid through a membrane. The membrane matrix is modeled as a series of flat parallel planes with circular pores of different sizes and random spatial distribution. This model was employed to determine how the size distribution of the colloidal filtrate depends on the size distributions of both, the particles in the feed and the pores of the membrane, as well as to describe the filtration kinetics. A Brownian dynamics simulation study considering normal distributions was developed in order to determine empirical correlations between the parameters that characterize these distributions. The model can also be extended to other distributions such as log-normal. This study could, therefore, facilitate the selection of membranes for industrial or scientific filtration processes once the size distribution of the feed is known and the expected characteristics in the filtrate have been defined.

Review of in-place HEPA filter testing at several DOE facilities

Energy Technology Data Exchange (ETDEWEB)

Mokler, B.V.; Scripsick, R.C. [Los Alamos National Laboratory, NM (United States)

1995-02-01

The Office of Nuclear Energy Self-Assessment recently sponsored reviews of HEPA filter systems at several DOE facilities. One aspect emphasized in these reviews was in-place filter testing practices. Although in-place testing was generally performed as required in facility specifications, we noted several areas in which improvements were possible. Examples of some common problems and approaches to their solution will be presented. Areas of suggested improvement include: (1) ensuring the validity of test results; (2) recognizing and quantifying the uncertainty in penetration measurements; (3) expanding the analysis and reporting of test results to provide more than pass/fail information; (4) addressing the special problems of multiple stage systems; and (5) increasing the technical support and training provided in-place testing personnel. Ensuring the validity of test results, for example, requires more careful attention to the operation of test equipment, checking test measurements and system operating parameters for internal consistency, and more attention to documentation of system geometry and operation. Some issues will require additional study before the results can be incorporated into decision making on filter bank testing requirements and performance specifications.

Review of in-place HEPA filter testing at several DOE facilities

International Nuclear Information System (INIS)

Mokler, B.V.; Scripsick, R.C.

1995-01-01

The Office of Nuclear Energy Self-Assessment recently sponsored reviews of HEPA filter systems at several DOE facilities. One aspect emphasized in these reviews was in-place filter testing practices. Although in-place testing was generally performed as required in facility specifications, we noted several areas in which improvements were possible. Examples of some common problems and approaches to their solution will be presented. Areas of suggested improvement include: (1) ensuring the validity of test results; (2) recognizing and quantifying the uncertainty in penetration measurements; (3) expanding the analysis and reporting of test results to provide more than pass/fail information; (4) addressing the special problems of multiple stage systems; and (5) increasing the technical support and training provided in-place testing personnel. Ensuring the validity of test results, for example, requires more careful attention to the operation of test equipment, checking test measurements and system operating parameters for internal consistency, and more attention to documentation of system geometry and operation. Some issues will require additional study before the results can be incorporated into decision making on filter bank testing requirements and performance specifications

Active osmotic exchanger for advanced filtration at the nano scale

Science.gov (United States)

Marbach, Sophie; Bocquet, Lyderic

2015-11-01

One of the main functions of the kidney is to remove the waste products of an organism, mostly by excreting concentrated urea while reabsorbing water and other molecules. The human kidney is capable of recycling about 200 liters of water per day, at the relatively low cost of 0.5 kJ/L (standard dialysis requiring at least 150 kJ/L). Kidneys are constituted of millions of parallel filtration networks called nephrons. The nephrons of all mammalian kidneys present a specific loop geometry, the Loop of Henle, that is believed to play a key role in the urinary concentrating mechanism. One limb of the loop is permeable to water and the other contains sodium pumps that exchange with a common interstitium. In this work, we take inspiration from this osmotic exchanger design to propose new nanofiltration principles. We first establish simple analytical results to derive general operating principles, based on coupled water permeable pores and osmotic pumps. The best filtration geometry, in terms of power required for a given water recycling ratio, is comparable in many ways to the mammalian nephron. It is not only more efficient than traditional reverse osmosis systems, but can also work at much smaller pressures (of the order of the blood pressure, 0.13 bar, as compared to more than 30 bars for pressure-retarded osmosis systems). We anticipate that our proof of principle will be a starting point for the development of new filtration systems relying on the active osmotic exchanger principle.

Experimental study on filtration and continuous regeneration of a particulate filter system for heavy-duty diesel engines.

Science.gov (United States)

Tang, Tao; Zhang, Jun; Cao, Dongxiao; Shuai, Shijin; Zhao, Yanguang

2014-12-01

This study investigated the filtration and continuous regeneration of a particulate filter system on an engine test bench, consisting of a diesel oxidation catalyst (DOC) and a catalyzed diesel particulate filter (CDPF). Both the DOC and the CDPF led to a high conversion of NO to NO2 for continuous regeneration. The filtration efficiency on solid particle number (SPN) was close to 100%. The post-CDPF particles were mainly in accumulation mode. The downstream SPN was sensitively influenced by the variation of the soot loading. This phenomenon provides a method for determining the balance point temperature by measuring the trend of SPN concentration. Copyright © 2014. Published by Elsevier B.V.

Filtration and retention capacities of filter aids

International Nuclear Information System (INIS)

Mellah, A.; Boualia, A.

1992-01-01

The present work involves the filtration of impure uranyl nitrate solutions by different filter aids such as kieselguhr, celite and bleaching clay. The retention of substances contained in uranyl nitrate solution was determined using the three filter aids. A study of the effects of granulometry and filter earths treatment (thermal and chemical) on the filtration rate was performed

Fire protection countermeasures for containment ventilation systems

International Nuclear Information System (INIS)

Alvares, N.; Beason, D.; Bergman, V.; Creighton, J.; Ford, H.; Lipska, A.

1980-01-01

The goal of this project is to find countermeasures to protect High Efficiency Particulate Air (HEPA) filters, in exit ventilation ducts, from the heat and smoke generated by fire. Initially, methods were developed to cool fire-heated air by fine water spray upstream of the filters. It was recognized that smoke aerosol exposure to HEPA filters could also cause disruption of the containment system. Through testing and analysis, several methods to partially mitigate the smoke exposure to the HEPA filters were identified. A continuous, movable, high-efficiency prefilter using modified commercial equipment was designed. The technique is capable of protecting HEPA filters over the total time duration of the test fires. The reason for success involved the modification of the prefiltration media. Commercially available filter media has particle sorption efficiency that is inversely proportional to media strength. To achieve properties of both efficiency and strength, rolling filter media were laminated with the desired properties. The approach was Edisonian, but truncation in short order to a combination of prefilters was effective. The application of this technique was qualified, since it is of use only to protect HEPA filters from fire-generated smoke aerosols. It is not believed that this technique is cost effective in the total spectrum of containment systems, especially if standard fire protection systems are available in the space. But in areas of high-fire risk, where the potential fuel load is large and ignition sources are plentiful, the complication of a rolling prefilter in exit ventilation ducts to protect HEPA filters from smoke aerosols is definitely justified

40 CFR 141.171 - Criteria for avoiding filtration.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Criteria for avoiding filtration. 141.171 Section 141.171 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection...

Tailored liquid chromatography-mass spectrometry analysis improves the coverage of the intracellular metabolome of HepaRG cells.

Science.gov (United States)

Cuykx, Matthias; Negreira, Noelia; Beirnaert, Charlie; Van den Eede, Nele; Rodrigues, Robim; Vanhaecke, Tamara; Laukens, Kris; Covaci, Adrian

2017-03-03

Metabolomics protocols are often combined with Liquid Chromatography-Mass Spectrometry (LC-MS) using mostly reversed phase chromatography coupled to accurate mass spectrometry, e.g. quadrupole time-of-flight (QTOF) mass spectrometers to measure as many metabolites as possible. In this study, we optimised the LC-MS separation of cell extracts after fractionation in polar and non-polar fractions. Both phases were analysed separately in a tailored approach in four different runs (two for the non-polar and two for the polar-fraction), each of them specifically adapted to improve the separation of the metabolites present in the extract. This approach improves the coverage of a broad range of the metabolome of the HepaRG cells and the separation of intra-class metabolites. The non-polar fraction was analysed using a C18-column with end-capping, mobile phase compositions were specifically adapted for each ionisation mode using different co-solvents and buffers. The polar extracts were analysed with a mixed mode Hydrophilic Interaction Liquid Chromatography (HILIC) system. Acidic metabolites from glycolysis and the Krebs cycle, together with phosphorylated compounds, were best detected with a method using ion pairing (IP) with tributylamine and separation on a phenyl-hexyl column. Accurate mass detection was performed with the QTOF in MS-mode only using an extended dynamic range to improve the quality of the dataset. Parameters with the greatest impact on the detection were the balance between mass accuracy and linear range, the fragmentor voltage, the capillary voltage, the nozzle voltage, and the nebuliser pressure. By using a tailored approach for the intracellular HepaRG metabolome, consisting of three different LC techniques, over 2200 metabolites can be measured with a high precision and acceptable linear range. The developed method is suited for qualitative untargeted LC-MS metabolomics studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Vibrating membrane filtration as improved technology for microalgae dewatering

OpenAIRE

Nurra, C.; Clavero, E.; Salvadó, J.; Torras, C.

2014-01-01

10.1016/j.biortech.2014.01.115 The effect of shear-enhanced filtration by vibratory process in microalgae dewatering is presented in this paper. The aim of this research was to investigate the technical performance and improvement of vibrating membrane filtration compared with conventional tangential cross-flow filtration in microalgae concentration. An industrial-scale available commercial set-up was used. Several membrane materials as polyethersulfone, polyacrylonitrile, etc., and mean ...

Scaling and particulate fouling in membrane filtration systems

NARCIS (Netherlands)

Boerlage, S.F.E.

2001-01-01

In the last decade, pressure driven membrane filtration processes; reverse osmosis, nano, ultra and micro-filtration have undergone steady growth. Drivers for this growth include desalination to combat water scarcity and the removal of various material from water to comply with increasingly

Vacuum distillation/vapor filtration water recovery

Science.gov (United States)

Honegger, R. J.; Neveril, R. B.; Remus, G. A.

1974-01-01

The development and evaluation of a vacuum distillation/vapor filtration (VD/VF) water recovery system are considered. As a functional model, the system converts urine and condensates waste water from six men to potable water on a steady-state basis. The system is designed for 180-day operating durations and for function on the ground, on zero-g aircraft, and in orbit. Preparatory tasks are summarized for conducting low gravity tests of a vacuum distillation/vapor filtration system for recovering water from urine.

Recent Trends in Nanofibrous Membranes and Their Suitability for Air and Water Filtrations

Directory of Open Access Journals (Sweden)

Seeram Ramakrishna

2011-08-01

Full Text Available In recent decades, engineered membranes have become a viable separation technology for a wide range of applications in environmental, food and biomedical fields. Membranes are now competitive compared to conventional techniques such as adsorption, ion exchangers and sand filters. The main advantage of membrane technology is the fact that it works without the addition of any chemicals, with relatively high efficiency and low energy consumption with well arranged process conductions. Hence they are widely utilized in biotechnology, food and drink manufacturing, air filtration and medical uses such as dialysis for kidney failure patients. Membranes from nanofibrous materials possess high surface area to volume ratio, fine tunable pore sizes and their ease of preparation prompted both industry and academic researchers to study their use in many applications. In this paper, modern concepts and current research progress on various nanofibrous membranes, such as water and air filtration media, are presented.

Industrial Application of Open Pore Ceramic Foam for Molten Metal Filtration

Science.gov (United States)

Gauckler, L. J.; Waeber, M. M.; Conti, C.; Jacob-Dulière, M.

Ceramic foam filters were used for industrial filtration of aluminum. Results are compared with laboratory experiments which are in good agreement with trajectory analyses of deep bed filtration for the early stage of filtration.

Dynamic optimization of a dead-end filtration trajectory: non-ideal cake filtration

NARCIS (Netherlands)

Blankert, B.; Kattenbelt, C.; Betlem, Bernardus H.L.; Roffel, B.

2007-01-01

A control strategy aimed at minimizing energy consumption is formulated for non-ideal dead-end cake filtration with an inside-out hollow fiber ultrafiltration membrane system. The non-ideal behavior was assumed to originate from cake compression, non-linear cake resistance and a variable pump

Functional principal component analysis of glomerular filtration rate curves after kidney transplant.

Science.gov (United States)

Dong, Jianghu J; Wang, Liangliang; Gill, Jagbir; Cao, Jiguo

2017-01-01

This article is motivated by some longitudinal clinical data of kidney transplant recipients, where kidney function progression is recorded as the estimated glomerular filtration rates at multiple time points post kidney transplantation. We propose to use the functional principal component analysis method to explore the major source of variations of glomerular filtration rate curves. We find that the estimated functional principal component scores can be used to cluster glomerular filtration rate curves. Ordering functional principal component scores can detect abnormal glomerular filtration rate curves. Finally, functional principal component analysis can effectively estimate missing glomerular filtration rate values and predict future glomerular filtration rate values.

CALCULATION OF LONG-TERM FILTRATION IN A POROUS MEDIUM

Directory of Open Access Journals (Sweden)

Ludmila I. Kuzmina

2018-03-01

Full Text Available he filtration problem in a porous medium is an important part of underground hydromechanics. Filtration of suspensions and colloids determines the processes of strengthening the soil and creating waterproof walls in the ground while building the foundations of buildings and underground structures. It is assumed that the formation of a deposit is dominated by the size-exclusion mechanism of pore blocking: solid particles pass freely through large pores and get stuck at the inlet of pores smaller than the diameter of the particles. A one-dimensional mathematical model for the filtration of a monodisperse suspension includes the equation for the mass balance of suspended and retained particles and the kinetic equation for the growth of the deposit. For the blocking filtration coefficient with a double root, the exact solution is given implicitly. The asymptotics of the filtration problem is constructed for large time. The numerical calculation of the problem is carried out by the finite differences method. It is shown that asymptotic approximations rapidly converge to a solution with the increase of the expansion order.

On a multiscale approach for filter efficiency simulations

KAUST Repository

Iliev, Oleg

2014-07-01

Filtration in general, and the dead end depth filtration of solid particles out of fluid in particular, is intrinsic multiscale problem. The deposition (capturing of particles) essentially depends on local velocity, on microgeometry (pore scale geometry) of the filtering medium and on the diameter distribution of the particles. The deposited (captured) particles change the microstructure of the porous media what leads to change of permeability. The changed permeability directly influences the velocity field and pressure distribution inside the filter element. To close the loop, we mention that the velocity influences the transport and deposition of particles. In certain cases one can evaluate the filtration efficiency considering only microscale or only macroscale models, but in general an accurate prediction of the filtration efficiency requires multiscale models and algorithms. This paper discusses the single scale and the multiscale models, and presents a fractional time step discretization algorithm for the multiscale problem. The velocity within the filter element is computed at macroscale, and is used as input for the solution of microscale problems at selected locations of the porous medium. The microscale problem is solved with respect to transport and capturing of individual particles, and its solution is postprocessed to provide permeability values for macroscale computations. Results from computational experiments with an oil filter are presented and discussed.

Study on the efficiency of the two phase partitioning stirred tank bioreactor on the toluene filtration from the airstream by Pseudomonas putida via

Directory of Open Access Journals (Sweden)

2013-02-01

Full Text Available Introduction: There are different methods for controlling gaseous pollutants formed from air pollution sources that one of the most economical and efficient of them, is bio-filtration. The purpose of this study is Toluene removal from airstream by using the pure Pseudomonas putida bacteria as a fluidized bed in a two phase partitioning stirred tank bioreactor.Toluene ( Metyle benzene is one of the aromatic compounds which uses as a chemical solvent.low to moderate concentration of Toluene causes fatigue, dizziness, weakness,unbalance behaviour, memory loss, insomnia, loss of appetite, loss of vision and hearing. .Material and Method: In this experimental study at first, pure Pseudomonas putida in an aqueous phase containing nutrients and trace elements solution was duplicated and accustomed with Toluene. then solution contained microorganisms with 10% silicon oil was entered to bioreactor. The amount of CO2 and pollutant concentrations in the entrance and exhaust of bioreactor containing Pseudomonas putida was studied during 17 days for each variable. .Result: Experimental findings showed that in the 0.06 m3/h and 0.12 m3/h flow rate, the efficiency of bioreactor containing Pseudomonas putida in the concentration ranges of 283 Mg/m3 to 4710 Mg/m3 was at least 97% and 25% respectively. Statistical analysis (ANOVA showed that in two flow rates of 0.06 m3/h and 0.12 m3/h removal efficiency and mineralization percentage had significant differences .(Pvalue =0.01. .Conclusion: Achieving high efficiencies in pollutants removal was because of the prepared optimum conditions for Pseudomonas putida in the two phase partitioning stirred tank bioreactor with 10% organic phase.

A new concept for filtration units for trapping radioactive aerosols and iodine in the ventilation systems of nuclear power plants with WWER reactors

International Nuclear Information System (INIS)

Foerster, V.; Slanina, S.

1985-01-01

The paper describes a concept for new filtration units in the ventilation systems of nuclear power plants with WWER reactors. The new units are characterized by more stringent requirements on the efficiency of air purification (removal of radioactive contaminants) and various requirements for the quality of air purification in the ventilation systems. Work performed at the Scientific Research Institute for Air Technology has resulted in filtration units of a universal modular type, the structural design of which permits a high degree of variation in their component parts. A brief description is given of the filtration units, their basic technical characteristics and examples of their use in nuclear power plant ventilation systems. (author)

Fate of leaf litter deposits and impacts on oxygen availability in bank filtration column studies.

Science.gov (United States)

Bayarsaikhan, Uranchimeg; Filter, Josefine; Gernert, Ulrich; Jekel, Martin; Ruhl, Aki Sebastian

2018-07-01

Degradation of particulate organic carbon (POC) such as leaf litter might deplete dissolved oxygen within the upper layers of bank filtration, an efficient and robust barrier for pathogens and for various organic micro-pollutants (OMP) in water supply systems worldwide. The degradation of OMP during bank filtration depends on the redox conditions. The present study aimed at identifying the impacts and fates of different local leaves on the oxygen consumption and the possible biological degradation of indicator OMP. Oxygen concentrations initially decreased within the columns from around 8 mg/L in the influent to low concentrations indicating extensive consumption within a short travel distance. Still a substantial oxygen consumption was observed after 250 days. OMP concentrations were not significantly affected by the microbial processes. A layer of calcium carbonate crystallites was observed on the POC layer. Some leaf fragments appeared to be persistant towards degradation and the carbon content relative to nitrogen and sulfur contents decreased within 250 days. The results demonstrate that trees at bank filtration sites might have a strong long-term impact on the subsurface redox conditions. Copyright © 2018 Elsevier Inc. All rights reserved.

Particulate Matter Filtration Design Considerations for Crewed Spacecraft Life Support Systems

Science.gov (United States)

Agui, Juan H.; Vijayakumar, R.; Perry, Jay L.

2016-01-01

Particulate matter filtration is a key component of crewed spacecraft cabin ventilation and life support system (LSS) architectures. The basic particulate matter filtration functional requirements as they relate to an exploration vehicle LSS architecture are presented. Particulate matter filtration concepts are reviewed and design considerations are discussed. A concept for a particulate matter filtration architecture suitable for exploration missions is presented. The conceptual architecture considers the results from developmental work and incorporates best practice design considerations.

Immobilized Filters for Air Filtration

National Research Council Canada - National Science Library

Mahle, John J; Zaiee, Saeed

2002-01-01

... (settling performance) and attrition resistance. The fabricated filter samples will be analyzed in order to determine the physical and chemical factors affecting mechanical strength and chemical filtration...

Leukocyte removal efficiency of cell-washed and unwashed whole blood: an in vitro study.

NARCIS (Netherlands)

Brinke, M. ten; Weerwind, P.W.; Teerenstra, S.; Feron, JC; Meer, W. van der; Brouwer, René

2005-01-01

Leukocyte filtration of the cardiopulmonary bypass (CPB) perfusate after cardiac surgery has evolved as an important technique to prevent effector functions mediated by activated leukocytes. However, little is known about the filtration efficiency. Therefore, an in vitro study was conducted to

Study of efficiency of particles removal by different filtration systems in a municipal wastewater tertiary treatment

International Nuclear Information System (INIS)

Andreu, P. S.; Lardin Mifsut, C.; Farinas Iglesias, M.; Sanchez-Arevalo Serrano, J.; Perez Sanchez, P.; Rancano Perez, A.

2009-01-01

The disinfection of municipal wastewater using ultraviolet radiation depends greatly on the presence within the water of particles in suspension. This work determines how the level of elimination of particles varies depending on the technique of filtration used (open, closed sand filters, with continuous washing of the sand, cloth, disk and ring filters). all systems are very effective in the removal of particles more than 25 microns and for removing helminth eggs. The membrane bio-reactors with ultrafiltration membranes were superior in terms of particle removal when compared to conventional filters. (Author) 11 refs.

Method of electrostatic filtration

International Nuclear Information System (INIS)

Devienne, F.M.

1975-01-01

Electrostatic filtration of secondary ions of mass m in a given mass ratio with a primary ion of mass M which has formed the secondary ions by fission is carried out by a method which consists in forming a singly-charged primary ion of the substance having a molecular mass M and extracting the ion at a voltage V 1 with respect to ground. The primary ion crosses a potential barrier V 2 , in producing the dissociation of the ion into at least two fragments of secondary ions and in extracting the fragment ion of mass m at a voltage V 2 . Filtration is carried out in an electrostatic analyzer through which only the ions of energy eV'' are permitted to pass, detecting the ions which have been filtered. The mass m of the ions is such that (M/m) = (V 1 - V 2 )/(V'' - V 2 )

Is the use of particle air filtration justified? Costs and benefits of filtration with regard to health effects, building cleaning and occupant productivity

DEFF Research Database (Denmark)

Bekö, Gabriel; Clausen, Geo; Weschler, Charles J.

2008-01-01

Estimates of costs and the corresponding benefits of particle filtration have been derived for a standard office building. Reduction in occupants’ exposure to particles during their workday is anticipated to reduce their morbidity and mortality. Filtration may also reduce the costs associated......, the sensitivity of the results to these parameters was evaluated as part of this study. The study also acknowledges that the benefits-to-costs ratio depends on the perspective of the stakeholder: the employer renting the building is impacted by occupant performance and building energy costs; the building owner...... is impacted by maintenance of the building and its HVAC system; society is impacted by the employees’ health and welfare. Regardless of perspective, particle filtration is anticipated to lead to annual savings significantly exceeding the running costs for filtration. However, economic losses resulting from...

Continuous improvements of defectivity rates in immersion photolithography via functionalized membranes in point-of-use photochemical filtration

Science.gov (United States)

D'Urzo, Lucia; Bayana, Hareen; Vandereyken, Jelle; Foubert, Philippe; Wu, Aiwen; Jaber, Jad; Hamzik, James

2017-03-01

Specific "killer-defects", such as micro-line-bridges are one of the key challenges in photolithography's advanced applications, such as multi-pattern. These defects generate from several sources and are very difficult to eliminate. Pointof-use filtration (POU) plays a crucial role on the mitigation, or elimination, of such defects. Previous studies have demonstrated how the contribution of POU filtration could not be studied independently from photoresists design and track hardware settings. Specifically, we investigated how an effective combination of optimized photoresist, filtration rate, filtration pressure, membrane and device cleaning, and single and multilayer filter membranes at optimized pore size could modulate the occurrence of such defects [1, 2, 3 and 4]. However, the ultimate desired behavior for POU filtration is the selective retention of defect precursor molecules contained in commercially available photoresist. This optimal behavior can be achieved via customized membrane functionalization. Membrane functionalization provides additional non-sieving interactions which combined with efficient size exclusion can selectively capture certain defect precursors. The goal of this study is to provide a comprehensive assessment of membrane functionalization applied on an asymmetric ultra-high molecular weight polyethylene (UPE) membrane at different pore size. Defectivity transferred in a 45 nm line 55 nm space (45L/55S) pattern, created through 193 nm immersion (193i) lithography with a positive tone chemically amplified resist (PT-CAR), has been evaluated on organic under-layer coated wafers. Lithography performance, such as critical dimensions (CD), line width roughness (LWR) and focus energy matrix (FEM) is also assessed.

MATHEMATIC MODEL OF ELECTROMAGNETIC FILTRATION PROCESS OF TECHNOLOGICAL LIQUID AND GAS

OpenAIRE

R. A. Мouradova

2005-01-01

Electromagnetic filtration as a perspective method of filtration and purification of liquid and gas finds its wide application in oil and chemical industry. However absence of highly-reliable model of calculation that permits unambiguously main operational parameters of electromagnetic filtration and limits its wide application. 

Filtration system for nuclear power plant

International Nuclear Information System (INIS)

Otani, Takashi; Nakamizo, Hiroshi.

1991-01-01

The filtration system of the present invention comprises a filtering device incorporating ceramic filament element bundles, a pool return line for returning filtrates to a side banker pool or fuel storage pool, a waste sludge discharge line for discharging waste sludges captured in the filter elements by way of washing operation and a settling separation vessel. Ceramics of excellent radiation resistance and having an extremely thin multi-layered structure at the surface are used for the filter elements. Highly radioactive cruds captured at the surface of the elements by liquid passage are removed by supplying water or gas in a pulsative manner in the direction opposite to the liquid passage thereby cleaning the surface of the elements at a high speed. The thus removed high radioactive cruds are concentrically confined within the settling separation layer by gravitational settling separation. Thus, there is no more necessary for disposing the filtration element bundles after use, so that the amount of wastes can be reduced, the radiation dosage can be lowered and the facility can be simplified. (N.H.)

Selecting Cells for Bioartificial Liver Devices and the Importance of a 3D Culture Environment: A Functional Comparison between the HepaRG and C3A Cell Lines

NARCIS (Netherlands)

van Wenum, Martien; Adam, Aziza A. A.; Hakvoort, Theodorus B. M.; Hendriks, Erik J.; Shevchenko, Valery; van Gulik, Thomas M.; Chamuleau, Robert A. F. M.; Hoekstra, Ruurdtje

2016-01-01

Recently, the first clinical trials on Bioartificial Livers (BALs) loaded with a proliferative human hepatocyte cell source have started. There are two cell lines that are currently in an advanced state of BAL development; HepaRG and HepG2/C3A. In this study we aimed to compare both cell lines on

Evaluation of condensate filtration technologies in fossil plants

Energy Technology Data Exchange (ETDEWEB)

D' Angelo, Philip J. [JoDan Technologies Ltd., Glen Mills, PA (United States)

2009-09-15

Long-term protection of electric power generating station boilers depends upon the quality of their feedwater chemistry with respect to the transport and deposition of corrosion products to the boilers from various corrosion sources in the plant's condensate and feedwater cycle. It is in the utility's best interests to expand their programs to include ways to reduce the transport of corrosion products, especially those that occur during plant start-ups. Condensate filtration is a strategy employed by some utilities with demonstrable results in minimizing corrosion product transport and achieving a return on their investment. This paper provides a comparative review of available condensate filtration technologies as well as performance data from fossil plants with the new large diameter high flow filtration systems. Additionally, the paper identifies critical parameters to consider before installation as well as the necessity for agreement between utilities and suppliers on common filtration terminology definitions, to insure an ''apple-to-apple'' basis when comparing a system or technology from more than one supplier. (orig.)

Innovative bio filtration for treatment of wastewater from communities and industry; Biofiltracion innovadora para el tratamiento de aguas residuales producidas por poblaciones e industrias

Energy Technology Data Exchange (ETDEWEB)

Sekoulov, I.; Rudiger, A.; Barz, M.

2009-07-01

Nowadays biological treatments are more and more required to clean municipal and industrial wastewater. More than 500 wastewater treatment plant use bio filtration. Bio filtration is a compact aerated reactor which does not imply expensive investments anymore. The real advantage of using bio filters is the aptitude to adapts the treatment to a wide range of entering polluting load, and also to low temperatures of wastewater. However, this technology needs a frequent cleaning that involves to stop the installation. Aquabiotec has solved this issue by enhancing a sequential cleaning. This new generation of bio filtration is able to treat wastewater steadily, with the same efficiency (>90%) and for lower costs compared to a classical bio filter. (Author) 6 refs.

Impact of Acidification on Pollutants Fate and Soil Filtration Function

Directory of Open Access Journals (Sweden)

Jarmila Makovniková

2014-12-01

Full Text Available The objective of this paper was to investigate the effects of simulated acid load on the fate of inorganic pollutants (Cd, Pb, soil sorption potential, soil filtration func-tion. We made use of a short-term acidification pot experiment with grown plant of spring barley cultivated at 4 different soil types (Fluvisol, Cambisol, Stagnosol, Podzol. The potential of soil filtration was evaluated according to the Eq.: [Soil filtration function]=[Potential of soil sorbents]+[Potential of total content of inor-ganic pollutants]. Potential of soil sorbents (PSS is defined by qualitative (pH, or-ganic matter quality - A400/600 and quantitative factors (carbon content-Cox, humus layer thickness-H according to the Eq.:[PSS]=F(pH+F(A465/665+F(Cox*F(H. Acid load significantly influenced soil sorption potential and thus affected increase in Cd and Pb mobility what was reflected in their transfer into the plants. Results of soil filtration function showed significant change of filtration function in Cambisol.

Real world efficiency of retrofit partial-flow diesel particulate filters for trucks

International Nuclear Information System (INIS)

Van Asch, R.; Verbeek, R.; Ligterink, N.; Kadijk, G.

2009-11-01

In 2006 the Dutch Ministry of Housing, Spatial Planning and the Environment (VROM) introduced an incentive scheme for retrofitting diesel particulate filters on Euro II and Euro III trucks. This scheme involves both partial flow and full flow diesel particulate filters (also called semi-open or open respectively wall-flow or closed filters). In the period 2007 till January 2009 about 15,000 partial flow filters and 8,000 full flow diesel particulate filters were installed. The minimum filtration efficiency requirement for the partial flow diesel particulate filters is 50% during the type approval test. In 2008 an engine dynamometer test programme was conducted to measure the filtration efficiency of retrofit open particulates filters of heavy trucks. This led to somewhat disappointing results with average filtration efficiencies in the range of 5-20% during city and national motorway driving conditions up to 20-40% during long distance motorway driving. This result leads to two main questions: (1) Is this result also representative for medium heavy trucks used for delivery, and (2) do similar efficiencies show up also in tests on entire vehicles, tested under conditions as close as possible to their real world usage profile. To this end, an additional measurement programme was defined, which is reported here. The objective of the study reported here is to determine the real world filtration efficiency of retrofit partial flow particulate filters for a number of trucks under different driving conditions such as city and motorway driving. The emphasis should be on medium heavy trucks typically used for national delivery.

Water Treatment Technology - Filtration.

Science.gov (United States)

Ross-Harrington, Melinda; Kincaid, G. David

One of twelve water treatment technology units, this student manual on filtration provides instructional materials for six competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: purposes of sedimentation basins and flocculation…

Fire protection countermeasures for containment ventilation systems

International Nuclear Information System (INIS)

Alvares, N.J.; Beason, D.G.; Bergman, W.; Ford, H.W.; Lipska, A.E.

1980-01-01

The goal of this project is to find countermeasures to protect HEPA filters in exit ventilation ducts from the heat and smoke generated by fire. Several methods for partially mitigating the smoke exposure to the HEPA filters were identified through testing and analysis. These independently involve controlling the fuel, controlling the fire, and intercepting the smoke aerosol prior to its sorption on the HEPA filter. Exit duct treatment of aerosols is not unusual in industrial applications and involves the use of scrubbers, prefilters, and inertial impaction, depending on the size, distribution, and concentration of the subject aerosol. However, when these unmodified techniques were applied to smoke aerosols from fires on materials, common to experimental laboratories of LLNL, it was found they offered minimal protection to the HEPA filters. Ultimately, a continuous, movable, high-efficiency prefilter using modified commercial equipment was designed. This technique is capable of protecting HEPA filters over the total duration of the test fires. The reason for success involved the modificaton of the prefiltration media. Commercially available filter media has a particle sorption efficiency that is inversely proportional to media strength. To achieve properties of both efficiency and strength, we laminated rolling filter media with the desired properties. It is not true that the use of rolling prefilters solely to protect HEPA filters from fire-generated smoke aerosols is cost effective in every type of containment system, especially if standard fire-protection systems are available in the space. But in areas of high fire risk, where the potential fuel load is large and ignition sources are plentiful, the complication of a rolling prefilter in exit ventilation ducts to protect HEPA filters from smoke aerosols is definitely justified

A Transcriptional Regulatory Network Containing Nuclear Receptors and Long Noncoding RNAs Controls Basal and Drug-Induced Expression of Cytochrome P450s in HepaRG Cells.

Science.gov (United States)

Chen, Liming; Bao, Yifan; Piekos, Stephanie C; Zhu, Kexin; Zhang, Lirong; Zhong, Xiao-Bo

2018-07-01

Cytochrome P450 (P450) enzymes are responsible for metabolizing drugs. Expression of P450s can directly affect drug metabolism, resulting in various outcomes in therapeutic efficacy and adverse effects. Several nuclear receptors are transcription factors that can regulate expression of P450s at both basal and drug-induced levels. Some long noncoding RNAs (lncRNAs) near a transcription factor are found to participate in the regulatory functions of the transcription factors. The aim of this study is to determine whether there is a transcriptional regulatory network containing nuclear receptors and lncRNAs controlling both basal and drug-induced expression of P450s in HepaRG cells. Small interfering RNAs or small hairpin RNAs were applied to knock down four nuclear receptors [hepatocyte nuclear factor 1 α (HNF1 α ), hepatocyte nuclear factor 4 α (HNF4 α ), pregnane X receptor (PXR), and constitutive androstane receptor (CAR)] as well as two lncRNAs [HNF1 α antisense RNA 1 (HNF1 α -AS1) and HNF4 α antisense RNA 1 (HNF4 α -AS1)] in HepaRG cells with or without treatment of phenobarbital or rifampicin. Expression of eight P450 enzymes was examined in both basal and drug-induced levels. CAR and PXR mainly regulated expression of specific P450s. HNF1 α and HNF4 α affected expression of a wide range of P450s as well as other transcription factors. HNF1 α and HNF4 α controlled the expression of their neighborhood lncRNAs, HNF1 α -AS1 and HNF4 α -AS1, respectively. HNF1 α -AS1 and HNF4 α -AS1 was also involved in the regulation of P450s and transcription factors in diverse manners. Altogether, our study concludes that a transcription regulatory network containing the nuclear receptors and lncRNAs controls both basal and drug-induced expression of P450s in HepaRG cells. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

Estimation of characteristics on high temperature filtration system for particle removal in vitrification process

International Nuclear Information System (INIS)

Park, Seung Chul; Ryu, Bo Hyun; Park, Byoung Chul; Ryu, Chang Soo; Hwang, Tae Won; Ha, Jong Hyun

2003-01-01

High temperature filtration technology has been widely used in nuclear industry systems to remove particulate matter from air and gas streams. Air filters are defined as porous structures through which air is passed to separate out entrained particulate matter. Especially among of them, ceramic candle filters are suitable to gain efficient dust removal at high temperatures and achieve high collection efficiencies for (sub-)micron particles. The paper presents experimental results for their application in the pilot scale vitrification plant operations. Experimental results were transformed into design equations for (i) total pressure drop and the effect of face velocity; (ii) the prediction of the operating parameters

Analysis of filtration properties of locally sourced base oil for the ...

African Journals Online (AJOL)

This study examines the use of locally sourced oil like, groundnut oil, melon oil, vegetable oil, soya oil and palm oil as substitute for diesel oil in formulating oil base drilling fluids relative to filtration properties. The filtrate volumes of each of the oils were obtained for filtration control analysis. With increasing potash and ...

[Pollution prevention and control of aqueous extract of astragali radix processed with ZrO2 inorganic ceramic membrane micro-filtration].

Science.gov (United States)

Pan, Lin-Men; Huang, Min-Yan; Guo, Li-Wei

2012-11-01

To study the measures for preventing and controlling the pollution of aqueous extract of Astragali Radix proceeded with inorganic ceramic membrane micro-filtration, in order to find effective measures for preventing and controlling the membrane pollution. The resistance distribution, polymer removal and changes in physical and chemical parameters of the zirconium oxide film of different pore diameters were determined to analyze the state or location of pollutants as well as the regularity of formation. Meanwhile, recoil and ultrasonic physical measures were adopted to strengthen the membrane process, in order to explore the methods for preventing and controlling the membrane pollution. When 0.2 microm of ZrO2 micro-filtrated aqueous extract of Astragali Radix, the rate of pollution was as high as 44.9%. The hole blocking resistance and the concentration polarization resistance were the main filtration resistances, while the surface deposit resistance decreased with the increase in the membrane's hold diameter; after micro-filtration, the liquid turbidity significantly reduced, with slight changes in both pH and viscosity. The 0.2 microm ZrO2 micro-filtration membrane performed better than the 0.05 microm pore size membrane in terms of conductivity. The 0. 2 microm and 0.05 microm pore diameter membranes showed better performance in the removal of pectin. The ultrasonic measure to strengthen membranes is more suitable to this system, with a flux rate up by 41.7%. The membrane optimization process adopts appropriate measures for preventing and controlling the membrane pollution, in order to reduce the membrane pollution, recover membrane performance and increase filtration efficiency.

Additive Difference Schemes for Filtration Problems in Multilayer Systems

CERN Document Server

Ayrjan, E A; Pavlush, M; Fedorov, A V

2000-01-01

In the present paper difference schemes for solution of the plane filtration problem in multilayer systems are analyzed within the framework of difference schemes general theory. Attention is paid to splitting the schemes on physical processes of filtration along water-carring layers and vertical motion between layers. Some absolutely stable additive difference schemes are obtained the realization of which needs no software modification. Parallel algorithm connected with the solving of the filtration problem in every water-carring layer on a single processor is constructed. Program realization on the multi-processor system SPP2000 at JINR is discussed.

High-efficiency particulate air filter test activities at the Department of Energy

International Nuclear Information System (INIS)

Bresson, J.F.

1987-01-01

For the past 2 years, test activities at the three Department of Energy HEPA Filter Test Facilities (FTFs) have been conducted under a unified set of operating standards intended to help achieve consistency in test methods and test results. Reviews of test operations are conducted at each FTF annually, and technical support and guidance are provided on request. Round Robin tests are conducted twice a year to compare penetration and resistance test results among the three FTFs. The FTFs prepare summary test data twice a year, and the data is analyzed for trends with respect to ongoing quality of HEPA filters in nuclear facilities. Data and conclusions from both the Round Robin tests and semiannual reports are discussed, the latter without reference to specific manufacturers. The new DOE standards include provisions for consideration and approval of new test aerosols or test methods, under closely controlled change procedures. Progress in obtaining DOE approval for DOS as a new aerosol, and for the Alternative Test System (ATS) developed by, and reported on by the LANL, as an approved new test method are discussed, as are 2 significant changes in standard NE-F-3-43, related to (a) toxicology test alternatives, and (b) the test aerosol definition. Finally, the emergence of new, higher flow rated HEPA filters and Ultra Low Particulate Air (ULPA) filters will impact DOE's design, procurement, testing and use of HEPA filters in the near future

Preliminary evaluation of fungicidal and termiticidal activities of filtrates from biomass slurry fuel production

Energy Technology Data Exchange (ETDEWEB)

Kartal, S.N. [Istanbul University (Turkey). Forestry Faculty; Imamura, Y. [Kyoto University (Japan). Wood Research Institute; Tsuchiya, F.; Ohsato, K. [JGC Corporation, Yokohama (Japan)

2004-10-01

Biomass slurry fuel (BSF) production has recently been developed as a natural energy for the conversion of solid biomass into fuel. In addition to using fuel, filtrates from BSF production may also serve a chemical source with several organic compounds. There is an increasing interest in the research and application of biomass-based filtrates. In this study, fungicidal and termiticidal properties of filtrates from BSF production using sugi (Cryptomeria japonica) and acacia (Acacia mangium) wood were evaluated in laboratory decay and termite resistance tests. Wood blocks treated with the filtrates showed increased resistance against brown-rot fungus, Formitopsis palustris. However the filtrates from sugi wood processed at 270{sup o}C which contained less phenolic compounds than the other filtrates were effective against white-rot fungus, Trametes versicolor. Phenolic compounds of filtrates seemed to play a role in the decay resistance tests however the filtrates did not increase the durability of the wood blocks against subterranean termites Coptotermes formosanus. Despite high acetic and lactic acid content of the filtrates, vanillin content of the filtrates may have served as an additional food source and promoted termite attack. It can be concluded that filtrates with phenolic compounds from lignin degradation during BSF production can be considered for targeted inhibition of brown-rot. (author)

Properties of plastic filtration material

Energy Technology Data Exchange (ETDEWEB)

Paluch, W.

1988-01-01

Discusses properties of filters made of thermoplastic granulated material. The granulated plastic has a specific density of 10.3-10.6 kN/m/sup 3/ and a bulk density of about 6 kN/m/sup 3/. Its chemical resistance to acids, bases and salts is high but is it soluble in organic solvents. Filters made of this material are characterized by a porosity coefficient of 36.5% and a bulk density of 5.7-6.8 kN/m/sup 3/. Physical and mechanical properties of filter samples made of thermoplastic granulated material (50x50x50 mm) were investigated under laboratory conditions. Compression strength and influencing factors were analyzed (ambient temperature, manufacturing technology). Tests show that this filtration material developed by Poltegor is superior to other filtration materials used in Poland.

A simple filtration method to remove plankton-associated Vibrio cholerae in raw water supplies in developing countries.

Science.gov (United States)

Huq, A; Xu, B; Chowdhury, M A; Islam, M S; Montilla, R; Colwell, R R

1996-07-01

Plankton to which cells of Vibrio cholerae O1 and/or O139 were attached was introduced into 0.5% Instant Ocean microcosms maintained at 25 degrees C. The bulk of the plankton and associated particulates was removed with a filter constructed from either nylon net and one of several different types of sari material, the latter being very inexpensive and readily available in villages in Bangladesh, where V. cholerae is endemic. V. cholerae was enumerated before and after filtration to evaluate the efficiency of the filtration procedure. The results obtained indicate that 99% of V. cholerae, i.e., those cells attached to plankton, were removed from the water samples. Epidemic strains of V. cholerae O1 and O139 from various geographical sources, including Bangladesh, Brazil, India, and Mexico, were included in the experiments. Removal of vibrios from water by this simple filtration method was found to yield consistent results with all strains examined in this study. Thus, it is concluded that a simple filtration procedure involving the use of domestic sari material can reduce the number of cholera vibrios attached to plankton in raw water from ponds and rivers commonly used for drinking. Since untreated water from such sources serves as drinking water for millions of people living in developing countries (e.g., Bangladesh), filtration should prove effective at reducing the incidence and severity of outbreaks, especially in places that lack fuel wood for boiling water and/or municipal water treatment plants. The results of this study provide the basis for determining such reductions, which are to be carried out in the near future.

Calculation code evaluating the confinement of a nuclear facility in case of fires

International Nuclear Information System (INIS)

Laborde, J.C.; Prevost, C.; Vendel, J.

1995-01-01

Accident events involving fire are quite frequent and could have a severe effect on the safety of nuclear facilities. As confinement must be maintained, the ventilation and filtration systems have to be designed to limit radioactive release to the environment. To determine and analyse the consequences of a fire on the contamination confinement, IPSN, COGEMA and SGN are participating in development of a calculation code based on introduction, in the SIMEVENT ventilation code, of various models associated to fire risk and mass transfer in the ventilation networks. This calculation code results from the coupling of the SIMEVENT code with several models describing the temperature in a room resulting of a fire, the temperatures along the ventilation ducts, the contamination transfers through out the ventilation equipments (ducts, dampers, valves, air cleaning systems) and the High Efficiency Particulate Air (HEPA) filters clogging. The paper proposed presents the current level of progress in development of this calculation code. It describes, in particular, the empirical model used for the clogging of HEPA filters by the aerosols derived from the combustion of standard materials used in the nuclear industry. It describes, also, the specific models used to take into account the mass transfers and resulting from the basic mechanisms of aerosols physics. In addition, an assessment of this code is given using the example of a simple laboratory installation

Calculation code evaluating the confinement of a nuclear facility in case of fires

Energy Technology Data Exchange (ETDEWEB)

Laborde, J.C.; Prevost, C.; Vendel, J. [and others

1995-02-01

Accident events involving fire are quite frequent and could have a severe effect on the safety of nuclear facilities. As confinement must be maintained, the ventilation and filtration systems have to be designed to limit radioactive release to the environment. To determine and analyse the consequences of a fire on the contamination confinement, IPSN, COGEMA and SGN are participating in development of a calculation code based on introduction, in the SIMEVENT ventilation code, of various models associated to fire risk and mass transfer in the ventilation networks. This calculation code results from the coupling of the SIMEVENT code with several models describing the temperature in a room resulting of a fire, the temperatures along the ventilation ducts, the contamination transfers through out the ventilation equipments (ducts, dampers, valves, air cleaning systems) and the High Efficiency Particulate Air (HEPA) filters clogging. The paper proposed presents the current level of progress in development of this calculation code. It describes, in particular, the empirical model used for the clogging of HEPA filters by the aerosols derived from the combustion of standard materials used in the nuclear industry. It describes, also, the specific models used to take into account the mass transfers and resulting from the basic mechanisms of aerosols physics. In addition, an assessment of this code is given using the example of a simple laboratory installation.

Microalgae fractionation using steam explosion, dynamic and tangential cross-flow membrane filtration.

Science.gov (United States)

Lorente, E; Hapońska, M; Clavero, E; Torras, C; Salvadó, J

2017-08-01

In this study, the microalga Nannochloropsis gaditana was subjected to acid catalysed steam explosion treatment and the resulting exploded material was subsequently fractionated to separate the different fractions (lipids, sugars and solids). Conventional and vibrational membrane setups were used with several polymeric commercial membranes. Two different routes were followed: 1) filtration+lipid solvent extraction and 2) lipid solvent extraction+filtration. Route 1 revealed to be much better since the used membrane for filtration was able to permeate the sugar aqueous phase and retained the fraction containing lipids; after this, an extraction required a much lower amount of solvent and a better recovering yield. Filtration allowed complete lipid rejection. Dynamic filtration improved permeability compared to the tangential cross-flow filtration. Best membrane performance was achieved using a 5000Da membrane with the dynamic system, obtaining a permeability of 6L/h/m 2 /bar. Copyright © 2017 Elsevier Ltd. All rights reserved.

Purification of contaminated water by filtration through porous glass

Science.gov (United States)

Wydeven, T.; Leban, M. I.

1972-01-01

Method for purifying water that is contaminated with mineral salts and soluble organic compounds is described. Method consists of high pressure filtration of contaminated water through stabilized porous glass membranes. Procedure for conducting filtration is described. Types of materials by percentage amounts removed from the water are identified.

Pathogen filtration to control plant disease outbreak in greenhouse production

Science.gov (United States)

Jeon, Sangho; Krasnow, Charles; Bhalsod, Gemini; Granke, Leah; Harlan, Blair; Hausbeck, Mary; Zhang, Wei

2016-04-01

Previous research has been extensively focused on understanding the fate and transport of human microbial pathogens in soil and water environments. However, little is known about the transport of plant pathogens, although these pathogens are often found in irrigation waters and could cause severe crop damage and economical loss. Water mold pathogens including Phytophthora spp. and Pythium spp. are infective to a wide range of vegetable and floriculture crops, and they are primarily harbored in soils and disseminated through water flow. It is challenging to control these pathogens because they often quickly develop resistance to many fungicides. Therefore, this multi-scale study aimed to investigate physical removal of plant pathogens from water by filtration, thus reducing the pathogen exposure risks to crops. In column-scale experiments, we studied controlling factors on the transport and retention of Phytophthora capsici zoospores in saturated columns packed with iron oxide coated-sand and uncoated-sand under varying solution chemistry. Biflagellate zoospores were less retained than encysted zoospores, and lower solution pH and greater iron oxide content increased the retention of encysted zoospores. These results provided insights on environmental dispersal of Phytophthora zoospores in natural soils as well as on developing cost-effective engineered filtration systems for pathogen removal. Using small-scale greenhouse filtration systems, we further investigated the performance of varying filter media (i.e., granular sand, iron oxide coated ceramic porous media, and activated carbon) in mitigating disease outbreaks of Phytophthora and Pythium for greenhouse-grown squash and poinsettia, respectively, in comparison with fungicide treatment. For squash, filtration by iron oxide coated media was more effective in reducing the Phytophthora infection, comparing to sand filtration and fungicide application. For poinsettia, sand filtration performed better in controlling

Interactions of liquid lithium with various atmospheres, concretes, and insulating materials; and filtration of lithium aerosols

International Nuclear Information System (INIS)

Jeppson, D.W.

1979-06-01

This report describes the facilities and experiments and presents test results of a program being conducted at the hanford Engineering Development Laboratory (HEDL) in support of the fusion reactor development effort. This experimental program is designed to characterize the interaction of liquid lithium with various atmospheres, concretes, and insulating materials. Lithium-atmosphere reaction tests were conducted in normal humidity air, pure nitrogen, and carbon dioxide. These tests are described and their results, such as maximum temperatures, aerosol generated, and reaction rates measured, are reported. Initial lithium temperatures for these tests ranged between 224 0 C and 843 0 C. A lithium-concrete reaction test, using 10 kg of lithium at 327 0 C, and lithium-insulating materials reaction tests, using a few grams of lithium at 350 0 C and 600 0 C, are also described and results are presented. In addition, a lithium-aerosol filter loading test was conducted to determine the mass loading capacity of a commercial high efficiency particulate air (HEPA) filter. The aerosol was characterized, and the loading-capacity-versus-pressure-buildup across the filter is reported

Horizontal-belt filtration at Randfontein Estates Mine

International Nuclear Information System (INIS)

Blendulf, K.A.G.; Everett, D.J.

1979-01-01

The paper describes tests on horizontal-belt filters for the filtration of gold and uranium. The promising results led to the installation of 17 such filters (ten of them 120 m 2 in size) in the mine's metallurgical plants, and their operation is discussed. Although several problems were encountered both in operation and maintenance, it is concluded that, with correct operation and suitable filter cloths, exceptionally good metallurgical recoveries can be achieved at filtration rates twice to three times higher than those on rotary filters [af

Low pressure drop filtration of airborne molecular organic contaminants using open-channel networks

Science.gov (United States)

Dallas, Andrew J.; Joriman, Jon; Ding, Lefei; Weineck, Gerald; Seguin, Kevin

2007-03-01

Airborne molecular contamination (AMC) continues to play a very decisive role in the performance of many microelectronic devices and manufacturing processes. Besides airborne acids and bases, airborne organic contaminants such as 1-methyl-2-pyrrolidinone (NMP), hexamethyldisiloxane (HMDSO), trimethylsilanol (TMS), perfluoroalkylamines and condensables are of primary concern in these applications. Currently, the state of the filtration industry is such that optimum filter life and removal efficiency for organics is offered by granular carbon filter beds. However, the attributes that make packed beds of activated carbon extremely efficient also impart issues related to elevated filter weight and pressure drop. Most of the lower pressure drop AMC filters currently offered are quite expensive and are simply pleated combinations of various adsorptive and reactive media. On the other hand, low pressure drop filters, such as those designed as open-channel networks (OCN's), offer good filter life and removal efficiency with the additional benefits of significant reductions in overall filter weight and pressure drop. Equally important for many applications, the OCN filters can reconstruct the airflow so as to enhance the operation of a tool or process. For tool mount assemblies and fan filter units (FFUs) this can result in reduced fan and blower speeds, which subsequently can provide reduced vibration and energy costs. Additionally, these low pressure drop designs can provide a cost effective way of effectively removing AMC in full fab (or HVAC) filtration applications without significantly affecting air-handling requirements. Herein, we will present a new generation of low pressure drop OCN filters designed for the removal of airborne organics in a wide range of applications.

Landfill Leachate Treatment by Electrocoagulation and Fiber Filtration.

Science.gov (United States)

Li, Runwei; Wang, Boya; Owete, Owete; Dertien, Joe; Lin, Chen; Ahmad, Hafiz; Chen, Gang

2017-11-01

  Landfilling is widely adopted as one of the most economical processes for solid waste disposal. At the same time, landfill leachate is also a great environmental concern owing to its complex composition and high concentrations of contaminants. This research investigated electrocoagulation and fiber filtration for the treatment of landfill leachate. Besides electrical current (i.e., current density) and reaction time, pH played a very important role in arsenic and phosphorus removal by electrocoagulation. The combination of electrocoagulation with fiber filtration achieved a 94% chemical oxygen demand (COD), 87% arsenic, 96% iron, and 86% phosphorus removal. During electrocoagulation, the micro-particles that could not be settled by gravity were removed by the first stage of fiber filtration. Organic contaminants in the leachate were further removed by biodegradation in the second stage of fiber biofiltration.

Penetration of sub-micron aerosol droplets in composite cylindrical filtration elements

International Nuclear Information System (INIS)

Geurts, Bernard J.; Pratte, Pascal; Stolz, Steffen; Stabbert, Regina; Poux, Valerie; Nordlund, Markus; Winkelmann, Christoph

2011-01-01

Advection-diffusion transport of aerosol droplets in composite cylindrical filtration elements is analyzed and compared to experimental data. The penetration, characterizing the fraction of droplets that passes through the pores of a filtration element, is quantified for a range of flow rates. The advection-diffusion transport in a laminar Poiseuille flow is treated numerically for slender pores using a finite difference approach in cylindrical coordinates. The algebraic dependence of the penetration on the Peclet number as predicted theoretically, is confirmed by experimental findings at a variety of aspect ratios of the cylindrical pores. The effective penetration associated with a composite filtration element consisting of a set of parallel cylindrical pores is derived. The overall penetration of heterogeneous composite filtration elements shows an algebraic dependence to the fourth power on the radii of the individual pores that are contained. This gives rise to strong variations in the overall penetration in cases with uneven distributions of pore sizes, highly favoring filtration by the larger pores. The overall penetration is computed for a number of basic geometries, providing a point of reference for filtration design and experimental verification.

The development of a HEPA filter with improved dust holding characteristics

International Nuclear Information System (INIS)

Dyment, J.; Hamblin, C.

1995-01-01

A limitation of the HEPA filters used in the extract of nuclear facilities is their relatively low capacity for captured dust. The costs associated with the disposal of a typical filter means that there are clear incentives to extend filter life. The work described in this report are the initial stages in the development of a filter which incorporates a medium which enhances its dust holding capacity. Experimental equipment was installed to enable the dust loading characteristics of candidate media to be compared with those of the glass fibre based papers currently used in filter construction. These tests involved challenging representative samples of the media with an air stream containing a controlled concentration of thermally generated sodium chloride particles. The dust loading characteristics of the media were then compared in terms of the rate of increasing in pressure differential. A number of open-quotes graded densityclose quotes papers were subsequently identified which appeared to offer significant improvements in dust holding. In the second phase of the programme deep-pleat filters (1,700 M 3 h -1 ) incorporating graded density papers were manufactured and tested. Improvements of up to 50% were observed in their capacity for the sub-micron sodium chloride test dust. Smaller differences (15%) were measured when a coarser, carbon black, challenge was used. This is attributed to the differences in the particles sizes of the two dusts

OPTIMIZATION OF THE PROCESS OF DRYING THE FILTRATE DISTILLERY DREGS

Directory of Open Access Journals (Sweden)

A. A. Shevtsov

2013-01-01

Full Text Available The interactions of various factors affecting the process of drying the filtrate distillery dregs are investigated. Rational conditions for the process of drying the filtrate distillery dregs in a spray dryer are obtained.

Sieve plugs in fenestrae of glomerular capillaries--site of the filtration barrier?

DEFF Research Database (Denmark)

Rostgaard, Jørgen; Qvortrup, Klaus

2002-01-01

The exact location of the filtration barrier of the glomerular capillary wall, which consists of an endothelium, a basement membrane and a visceral epithelium, has not yet been determined. Apparent discrepancies between different investigators in the past could be explained if postmortem...... and a filamentous surface coat about 60 nm thick covered the interfenestral domains of the endothelial cell. Based on these purely morphological data, we dare to suggest that the fenestral plugs are the primary site of the glomerular filtration barrier - albeit highly speculative, nevertheless a logical location...... - and consequently that the glomerular filtration process is a 'tangential-flow' as opposed to a 'dead-end' filtration process. A tangential-flow filtration would minimize 'clogging' and 'concentration polarization' in the 'filter'....

Filtration assay for quantitation of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) specific binding to whole cells in culture

International Nuclear Information System (INIS)

Dold, K.M.; Greenlee, W.F.

1990-01-01

A rapid and sensitive filtration assay for quantitating the specific binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to whole cells in culture is described. Cell monolayers are incubated with [3H]TCDD in the presence or absence of excess unlabeled ligand, detached from the culture dish with trypsin, filtered, and washed with cold (-78 degrees C) acetone to separate free and nonspecifically bound TCDD from specifically bound TCDD. TCDD receptor binding parameters were characterized in the murine hepatoma cell line Hepa1c1c7. The lower limit of detection of TCDD specific binding was in a sample equivalent to 10 micrograms of total cell protein. The equilibrium dissociation constant and stereospecificity for binding to the TCDD receptor were the same as those previously reported with other TCDD receptor assays on broken cell preparations. Analysis of binding in the murine hepatoma TCDD receptor variants TAO-c1BPrc1 and BPrc1 indicated that this assay will detect receptor number or affinity variants, but will not detect nuclear transfer deficient variants. The major advantage of the whole cell binding assay is that it provides the means to rapidly and reproducibly quantitate TCDD specific binding in small samples of whole cells in culture. In addition, this method eliminates loss or degradation of the receptor protein during the fractionation of cells required in previously reported methods. This method should prove useful in screening clonal cell populations for TCDD receptor number and affinity variants, and in screening for TCDD receptor binding activity in complementation studies of receptor deficient cells

Statistical data filtration in neutron coincidence counting

International Nuclear Information System (INIS)

Beddingfield, D.H.; Menlove, H.O.

1992-11-01

We assessed the effectiveness of statistical data filtration to minimize the contribution of matrix materials in 200-ell drums to the nondestructive assay of plutonium. Those matrices were examined: polyethylene, concrete, aluminum, iron, cadmium, and lead. Statistical filtration of neutron coincidence data improved the low-end sensitivity of coincidence counters. Spurious data arising from electrical noise, matrix spallation, and geometric effects were smoothed in a predictable fashion by the statistical filter. The filter effectively lowers the minimum detectable mass limit that can be achieved for plutonium assay using passive neutron coincidence counting

Task 9 - Centrifugal membrane filtration. Semi-annual report, April 1 - September 30, 1997

International Nuclear Information System (INIS)

Stepan, D.J.; Grafsgaard, M.E.

1997-01-01

This project is designed to establish the utility of a novel centrifugal membrane filtration technology for the remediation of liquid mixed waste streams at US Department of Energy (DOE) facilities in support of the DOE Environmental Management (EM) program. The Energy and Environmental Research Center (EERC) has teamed with SpinTek Membrane Systems, Inc., a small business and owner of the novel centrifugal membrane filtration technology, to establish the applicability of the technology to DOE site remediation and the commercial viability of the technology for liquid mixed waste stream remediation. The technology is a uniquely configured process that makes use of ultrafiltration and centrifugal force to separate suspended and dissolved solids from liquid waste streams, producing a filtered water stream and a low-volume contaminated concentrate stream. This technology has the potential for effective and efficient waste volume minimization, the treatment of liquid tank wastes, the remediation of contaminated groundwater plumes, and the treatment of secondary liquid waste streams from other remediation processes, as well as the liquid waste stream generated during decontamination and decommissioning activities

Activation of the sonic hedgehog signaling pathway occurs in the CD133 positive cells of mouse liver cancer Hepa 1–6 cells

Directory of Open Access Journals (Sweden)

Jeng KS

2013-08-01

Full Text Available Kuo-Shyang Jeng,1 I-Shyan Sheen,2 Wen-Juei Jeng,2 Ming-Che Yu,3 Hsin-I Hsiau,3 Fang-Yu Chang,3 Hsin-Hua Tsai31Department of Surgery, Far Eastern Memorial Hospital, Taipei, 2Department of Hepato-Gastroenterology, Chang Gung Memorial Hospital, Linkou Medical Center, Chang Gung University, 3Department of Medical Research, Far Eastern Memorial Hospital, Taipei, Taiwan, Republic of ChinaBackground: The important role of cancer stem cells in carcinogenesis has been emphasized in research. CD133+ cells have been mentioned as liver cancer stem cells in hepatocellular carcinoma (HCC. Some researchers have proposed that the sonic hedgehog (Shh pathway contributes to hepatocarcinogenesis and that the pathway activation occurs mainly in cancer stem cells. We investigated whether the activation of the Shh pathway occurs in CD133+ cells from liver cancer.Materials and methods: We used magnetic sorting to isolate CD133+ cells from mouse cancer Hepa 1–6 cells. To examine the clonogenicity, cell culture and soft agar colony formation assay were performed between CD133+ and CD133- cells. To study the activation of the Shh pathway, we examined the mRNA expressions of Shh, patched homolog 1 (Ptch-1, glioma-associated oncogene homolog 1 (Gli-1, and smoothened homolog (Smoh by real-time polymerase chain reaction of both CD133+ and CD133- cells.Results: The number (mean ± standard deviation of colonies of CD133+ cells and CD133- cells was 1,031.0 ± 104.7 and 119.7 ± 17.6 respectively. This difference was statistically significant (P < 0.001. Their clonogenicity was 13.7% ± 1.4% and 1.6% ± 0.2% respectively with a statistically significant difference found (P < 0.001. CD133+ cells and CD133– cells were found to have statistically significant differences in Shh mRNA and Smoh mRNA (P = 0.005 and P = 0.043 respectively.Conclusion: CD133+ Hepa 1–6 cells have a significantly higher colony proliferation and clonogenicity. The Shh pathway is activated in these

Oviposition Attractancy of Bacterial Culture Filtrates: response of Culex quinquefasciatus

Directory of Open Access Journals (Sweden)

S Poonam

2002-04-01

Full Text Available Oviposition attractants could be used for monitoring as well as controlling mosquitoes by attracting them to lay eggs at chosen sites. In the present study, culture filtrates of seven bacterial species were tested for their attractancy against gravid females of Culex quinquefasciatus. When their oviposition active indices (OAI were studied, the culture filtrates of Bacillus cereus and Pseudomonas fluorescens exhibited oviposition attractancy (OAI = >0.3 at 100 ppm and the OAI were respectively 0.70 and 0.47. Culture filtrates of B. thuringiensis var. israelensis (wild type, B. t. var. israelensis (mutant and B. sphaericus showed attractancy at 2000 ppm with OAI of respectively 0.71, 0.59 and 0.68. However, the OAI of B. megaterium as well as Azospirillum brasilense was 0.13 (at 2000 ppm, which was less than 0.3 required to be considered them as attractants. When the oviposition attractancy of the bacterial culture filtrates were compared with that of a known oviposition attractant, p-cresol (at 10 ppm, the culture filtrates of B. t. var. israelensis (wild type and B. cereus were found to be more active than p-cresol, respectively with 64.2 and 54.3% oviposition.

Filtration characteristics in membrane bioreactors

NARCIS (Netherlands)

Evenblij, H.

2006-01-01

Causes of and remedies for membrane fouling in Membrane Bioreactors for wastewater treatment are only poorly understood and described in scientific literature. A Filtration Characterisation Installation and a measurement protocol were developed with the aim of a) unequivocally determination and

Filtration device for active effluents

International Nuclear Information System (INIS)

Guerin, M.; Meunier, G.

1994-01-01

Among the various techniques relating to solid/liquid separations, filtration is currently utilized for treating radioactive effluents. After testing different equipments on various simulated effluents, the Valduc Center has decided to substitute a monoplate filter for a rotative diatomite precoated filter

Mixture based outlier filtration

Czech Academy of Sciences Publication Activity Database

Pecherková, Pavla; Nagy, Ivan

2006-01-01

Roč. 46, č. 2 (2006), s. 30-35 ISSN 1210-2709 R&D Projects: GA MŠk 1M0572; GA MDS 1F43A/003/120 Institutional research plan: CEZ:AV0Z10750506 Keywords : data filtration * system modelling * mixture models Subject RIV: BD - Theory of Information http://library.utia.cas.cz/prace/20060165.pdf

Combination of granular activated carbon adsorption and deep-bed filtration as a single advanced wastewater treatment step for organic micropollutant and phosphorus removal.

Science.gov (United States)

Altmann, Johannes; Rehfeld, Daniel; Träder, Kai; Sperlich, Alexander; Jekel, Martin

2016-04-01

Adsorption onto granular activated carbon (GAC) is an established technology in water and advanced wastewater treatment for the removal of organic substances from the liquid phase. Besides adsorption, the removal of particulate matter by filtration and biodegradation of organic substances in GAC contactors has frequently been reported. The application of GAC as both adsorbent for organic micropollutant (OMP) removal and filter medium for solids retention in tertiary wastewater filtration represents an energy- and space saving option, but has rarely been considered because high dissolved organic carbon (DOC) and suspended solids concentrations in the influent of the GAC adsorber put a significant burden on this integrated treatment step and might result in frequent backwashing and unsatisfactory filtration efficiency. This pilot-scale study investigates the combination of GAC adsorption and deep-bed filtration with coagulation as a single advanced treatment step for simultaneous removal of OMPs and phosphorus from secondary effluent. GAC was assessed as upper filter layer in dual-media downflow filtration and as mono-media upflow filter with regard to filtration performance and OMP removal. Both filtration concepts effectively removed suspended solids and phosphorus, achieving effluent concentrations of 0.1 mg/L TP and 1 mg/L TSS, respectively. Analysis of grain size distribution and head loss within the filter bed showed that considerable head loss occurred in the topmost filter layer in downflow filtration, indicating that most particles do not penetrate deeply into the filter bed. Upflow filtration exhibited substantially lower head loss and effective utilization of the whole filter bed. Well-adsorbing OMPs (e.g. benzotriazole, carbamazepine) were removed by >80% up to throughputs of 8000-10,000 bed volumes (BV), whereas weakly to medium adsorbing OMPs (e.g. primidone, sulfamethoxazole) showed removals activated carbon (PAC) to deep-bed filtration as a direct

Numerical Solutions of Mechanical Turbulent Filtration Equation Used in Mechatronics and Micro Mechanic

OpenAIRE

Hassan Fathabadi

2013-01-01

In this study, several novel numerical solutions are presented to solve the turbulent filtration equation and its special case called “Non-Newtonian mechanical filtration equation”. The turbulent filtration equation in porous media is a very important equation which has many applications to solve the problems appearing especially in mechatronics, micro mechanic and fluid mechanic. Many applied mechanical problems can be solved using this equation. For example, non-Newtonian mechanical filtrat...

Modeling of Filtration Processes—Microfiltration and Depth Filtration for Harvest of a Therapeutic Protein Expressed in Pichia pastoris at Constant Pressure

Directory of Open Access Journals (Sweden)

Muthukumar Sampath

2014-12-01

Full Text Available Filtration steps are ubiquitous in biotech processes due to the simplicity of operation, ease of scalability and the myriad of operations that they can be used for. Microfiltration, depth filtration, ultrafiltration and diafiltration are some of the most commonly used biotech unit operations. For clean feed streams, when fouling is minimal, scaling of these unit operations is performed linearly based on the filter area per unit volume of feed stream. However, for cases when considerable fouling occurs, such as the case of harvesting a therapeutic product expressed in Pichia pastoris, linear scaling may not be possible and current industrial practices involve use of 20–30% excess filter area over and above the calculated filter area to account for the uncertainty in scaling. In view of the fact that filters used for harvest are likely to have a very limited lifetime, this oversizing of the filters can add considerable cost of goods for the manufacturer. Modeling offers a way out of this conundrum. In this paper, we examine feasibility of using the various proposed models for filtration of a therapeutic product expressed in Pichia pastoris at constant pressure. It is observed that none of the individual models yield a satisfactory fit of the data, thus indicating that more than one fouling mechanism is at work. Filters with smaller pores were found to undergo fouling via complete pore blocking followed by cake filtration. On the other hand, filters with larger pores were found to undergo fouling via intermediate pore blocking followed by cake filtration. The proposed approach can be used for more accurate sizing of microfilters and depth filters.

Effect of operation parameters on the flux stabilization of gravity-driven membrane (GDM) filtration system for decentralized water supply.

Science.gov (United States)

Tang, Xiaobin; Ding, An; Qu, Fangshu; Jia, Ruibao; Chang, Haiqing; Cheng, Xiaoxiang; Liu, Bin; Li, Guibai; Liang, Heng

2016-08-01

A pilot-scale gravity-driven membrane (GDM) filtration system under low gravitational pressure without any pre-treatment, backwash, flushing, or chemical cleaning was carried out to investigate the effect of operation parameters (including operation pressure, aeration mode, and intermittent filtration) on the effluent quality and permeability development. The results revealed that GDM system exhibited an efficient performance for the removal of suspended substances and organic compounds. The stabilization of flux occurred and the average values of stable flux were 6.6, 8.1, and 8.6 Lm(-2) h(-1) for pressures of 65, 120, and 200 mbar, respectively. In contrast, flux stabilization was not observed under continuous and intermittent aeration conditions. However, aeration (especially continuous aeration) was effective to improve flux and alleviate membrane fouling during 1-month operation. Moreover, intermittent filtration would influence the stabilization of permeate flux, resulting in a higher stable flux (ranging from 6 to 13 Lm(-2) h(-1)). The stable flux significantly improved with the increase of intermittent period. Additionally, GDM systems exhibited an efficient recovery of flux after simple physical cleaning and the analyses of resistance reversibility demonstrated that most of the total resistance was hydraulic reversible resistance (50-75 %). Therefore, it is expected that the results of this study can develop strategies to increase membrane permeability and reduce energy consumption in GDM systems for decentralized water supply.

Non-filtration method of processing uranium ores

International Nuclear Information System (INIS)

Laskorin, B.N.; Vodolazov, L.I.; Tokarev, N.N.; Vyalkov, V.I.; Goldobina, V.A.; Gosudarstvennyj Komitet po Ispol'zovaniyu Atomnoj Ehnergii SSSR, Moscow)

1977-01-01

The development of the non-filtration sorption method has lead to procedures of the sorption leaching and the extraction desorption, which have made it possible to intensify the processing of uranium ores and to improve greatly the technical and economic indexes by eliminating the complex method of multiple filtration and re-pulping of cakes. This method makes it possible to involve more poor uranium raw materials, at the same time extracting valuable components such as molybdenum, vanadium, copper, etc. Considerable industrial experience has been acquired in the sorption of dense pulp with a solid-to-liquid phase ratio of 1:1. This has led to a plant production increase of 1.5-3.0 times, an increase of uranium extraction by 5-10%, a two- to- three-fold increase of labour capacity of the main workers, and to a several-fold decrease of reagents, auxiliary materials, electric energy and vapour. This non-filtration method is a continuous process in all its phases thanks to the use of high-yield and high-power equipment for high-density pulps. (author)

Ultra-filtration measurement using CT imaging technology

International Nuclear Information System (INIS)

Lu Junfeng; Lu Wenqiang

2009-01-01