Pollutant removal in subsurface wastewater infiltration systems with ...

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Pollutant removal in subsurface wastewater infiltration systems with/without intermittent ... Water SA. Journal Home · ABOUT THIS JOURNAL · Advanced Search ... wastewater infiltration systems (SWISs) with and without intermittent aeration, ...

Modelling Cr(VI) removal by a combined carbon-activated sludge system

International Nuclear Information System (INIS)

Orozco, A. Micaela Ferro; Contreras, Edgardo M.; Zaritzky, Noemi E.

2008-01-01

The combined carbon-activated sludge process has been proposed as an alternative to protect the biomass against toxic substances in wastewaters; however, the information about the effect of powdered-activated carbon (PAC) addition in activated sludge reactors for the treatment of wastewaters containing Cr(VI) is limited. The objectives of the present study were: (a) to evaluate the removal of hexavalent chromium by (i) activated sludge microorganisms in aerobic batch reactors, (ii) powdered-activated carbon, and (iii) the combined action of powdered-activated carbon and biomass; (b) to propose mathematical models that interpret the experimental results. Different Cr(VI) removal systems were tested: (S1) biomass (activated sludge), (S2) PAC, and (S3) the combined activated carbon-biomass system. A Monod-based mathematical model was used to describe the kinetics of Cr(VI) removal in the system S1. A first-order kinetics with respect to Cr(VI) and PAC respectively, was proposed to model the removal of Cr(VI) in the system S2. Cr(VI) removal in the combined carbon-biomass system (S3) was faster than both Cr(VI) removal using PAC or activated sludge individually. Results showed that the removal of Cr(VI) using the activated carbon-biomass system (S3) was adequately described by combining the kinetic equations proposed for the systems S1 and S2

Hybrid disposal systems and nitrogen removal in individual sewage disposal systems

Energy Technology Data Exchange (ETDEWEB)

Franks, A.L.

1993-06-01

The use of individual disposal systems in ground-water basins that have adverse salt balance conditions and/or geologically unsuitable locations, has become a major problem in many areas of the world. There has been much research in design of systems for disposal of domestic sewage. This research includes both hybrid systems for disposal of domestic sewage. This research includes both hybrid systems for disposal of the treated waste in areas with adverse geologic conditions and systems for the removal of nitrogen and phosphorus prior to percolation to the ground water. This paper outlines the history of development and rationale for design and construction of individual sewage disposal systems and describes the designs and limitations of the hybrid and denitrification units. The disposal systems described include Mounds, Evapotranspiration and Evapotranspiration/Infiltration systems. The denitrification units include those using methanol, sulfur and limestone, gray water and secondary treated wastewater for energy sources.

Radiological/biological/aerosol removal system

Science.gov (United States)

Haslam, Jeffery J

2015-03-17

An air filter replacement system for existing buildings, vehicles, arenas, and other enclosed airspaces includes a replacement air filter for replacing a standard air filter. The replacement air filter has dimensions and air flow specifications that allow it to replace the standard air filter. The replacement air filter includes a filter material that removes radiological or biological or aerosol particles.

A review of virus removal in wastewater treatment pond systems.

Science.gov (United States)

Verbyla, Matthew E; Mihelcic, James R

2015-03-15

Wastewater treatment ponds (lagoons) are one of the most common types of technologies used for wastewater management worldwide, especially in small cities and towns. They are particularly well-suited for systems where the effluent is reused for irrigation. However, the efficiency of virus removal in wastewater treatment pond systems is not very well understood. The main objective of this paper is to critically review the major findings related to virus removal in wastewater treatment pond systems and to statistically analyze results reported in the literature from field studies on virus removal in these systems. A comprehensive analysis of virus removal reported in the literature from 71 different wastewater treatment pond systems reveals only a weak to moderate correlation of virus removal with theoretical hydraulic retention time. On average, one log10 reduction of viruses was achieved for every 14.5-20.9 days of retention, but the 95th percentile value of the data analyzed was 54 days. The mechanisms responsible for virus removal in wastewater treatment ponds were also reviewed. One recent finding is that sedimentation may not be a significant virus removal mechanism in some wastewater ponds. Recent research has also revealed that direct and indirect sunlight-mediated mechanisms are not only dependent on pond water chemistry and optics, but also on the characteristics of the virus and its genome. MS2 coliphage is considered to be the best surrogate for studying sunlight disinfection in ponds. The interaction of viruses with particles, with other microorganisms, and with macroinvertebrates in wastewater treatment ponds has not been extensively studied. It is also unclear whether virus internalization by higher trophic-level organisms has a protective or a detrimental effect on virus viability and transport in pond systems. Similarly, the impact of virus-particle associations on sunlight disinfection in ponds is not well understood. Future research should focus on

Passive heat removal system with injector-condenser

Energy Technology Data Exchange (ETDEWEB)

Soplenkov, K I [All-Russian Inst. of Nuclear Power Plant Operation, Electrogorsk Research and Engineering Centre of Nuclear Power Safety (Russian Federation)

1996-12-01

The system described in this paper is a passive system for decay heat removal from WWERs. It operates off the secondary side of the steam generators (SG). Steam is taken from the SG to operate a passive injector pump which causes secondary fluid to be pumped through a heat exchanger. Variants pass either water or steam from the SG through the heat exchanger. There is a passive initiation scheme. The programme for experimental and theoretical validation of the system is described. (author). 8 figs.

Water removal from a dry barrier cover system

International Nuclear Information System (INIS)

Stormont, J.C.; Ankeny, M.D.; Tansey, M.K.

1994-01-01

The results of the numerical simulations reveal that horizontal air flow through the coarse with reasonable pressure gradients can remove large quantities of water from the cover system. Initially, the water removal from the cover system is dominated by the evaporation and advection of water vapor out of the coarse layer. Once the coarse layer is dry, removal of water by evaporation near the fine/coarse layer interface reduces the local water content and water potential, and water moves toward the fine-coarse layer interface and becomes available for evaporation. This result is important in that it suggests the fine layer water content may be moderated by air flow in the coarse layer. Incorporating diffusion of water vapor from the fine layer into the coarse layer substantially increases the water movement out of the fine layer

Control of the ASTRA decay heat removal system

International Nuclear Information System (INIS)

Nedelik, A.

1982-11-01

To ensure a minimum of core cooling even under severest accident conditions (loss of reactor pool water) a core spray system for decay heat removal has been installed at the ASTRA-reactor. The automatic and manual control of the system, its power supply and test procedures are shortly described. (Author)

An innovative pool with a passive heat removal system

International Nuclear Information System (INIS)

Vitale Di Maio, Damiano; Naviglio, Antonio; Giannetti, Fabio; Manni, Fabio

2012-01-01

Heat removal systems are of primary importance in several industrial processes. As heat sink, a water pool or atmospheric air may be selected. The first solution takes advantage of high heat transfer coefficient with water but it requires active systems to maintain a constant water level; the second solution takes benefit from the unlimited heat removal capacity by air, but it requires a larger heat exchanger to compensate the lower heat transfer coefficient. In NPPs (nuclear power plants) during a nuclear reactor shutdown, as well as in some chemical plants to control runaway reactions, it is possible to use an innovative heat sink that joins the advantages of the two previous solutions. This solution is based on a special heat exchanger submerged in a water pool designed so that when heat removal is requested, active systems are not required to maintain the water level; due to the special design, when the pool is empty, atmospheric air becomes the only heat sink. The special heat exchanger design allows to have a heat exchanger without being oversized and to have a system able to operate for unlimited period without external interventions. This innovative system provides an economic advantage as well as enhanced safety features.

Fermilab satellite refrigerator compressors with the oil- and moisture-removal systems

International Nuclear Information System (INIS)

Satti, J.A.; Andrews, R.A.

1983-08-01

We have designed and tested a helium purification system for the Energy Doubler and the experimental areas. A purification system is installed after each screw compressor in the satellite refrigerators. The purification system removes oil mist, oil vapor, water vapor, and particulate from the compressed helium. The units were designed with consideration of modularity and necessary redundancy (i.e., guard purification). Test results which led to the final configuration are presented, along with achieved performance of the oil removal in the operating system

Nuclear reactor with makeup water assist from residual heat removal system

Science.gov (United States)

Corletti, Michael M.; Schulz, Terry L.

1993-01-01

A pressurized water nuclear reactor uses its residual heat removal system to make up water in the reactor coolant circuit from an in-containment refueling water supply during staged depressurization leading up to passive emergency cooling by gravity feed from the refueling water storage tank, and flooding of the containment building. When depressurization commences due to inadvertence or a manageable leak, the residual heat removal system is activated manually and prevents flooding of the containment when such action is not necessary. Operation of the passive cooling system is not impaired. A high pressure makeup water storage tank is coupled to the reactor coolant circuit, holding makeup coolant at the operational pressure of the reactor. The staged depressurization system vents the coolant circuit to the containment, thus reducing the supply of makeup coolant. The level of makeup coolant can be sensed to trigger opening of successive depressurization conduits. The residual heat removal pumps move water from the refueling water storage tank into the coolant circuit as the coolant circuit is depressurized, preventing reaching the final depressurization stage unless the makeup coolant level continues to drop. The residual heat removal system can also be coupled in a loop with the refueling water supply tank, for an auxiliary heat removal path.

Nuclear reactor with makeup water assist from residual heat removal system

International Nuclear Information System (INIS)

Corletti, M.M.; Schulz, T.L.

1993-01-01

A pressurized water nuclear reactor uses its residual heat removal system to make up water in the reactor coolant circuit from an in-containment refueling water supply during staged depressurization leading up to passive emergency cooling by gravity feed from the refueling water storage tank, and flooding of the containment building. When depressurization commences due to inadvertence or a manageable leak, the residual heat removal system is activated manually and prevents flooding of the containment when such action is not necessary. Operation of the passive cooling system is not impaired. A high pressure makeup water storage tank is coupled to the reactor coolant circuit, holding makeup coolant at the operational pressure of the reactor. The staged depressurization system vents the coolant circuit to the containment, thus reducing the supply of makeup coolant. The level of makeup coolant can be sensed to trigger opening of successive depressurization conduits. The residual heat removal pumps move water from the refueling water storage tank into the coolant circuit as the coolant circuit is depressurized, preventing reaching the final depressurization stage unless the makeup coolant level continues to drop. The residual heat removal system can also be coupled in a loop with the refueling water supply tank, for an auxiliary heat removal path. 2 figures

Nuclear reactor with makeup water assist from residual heat removal system

Science.gov (United States)

Corletti, M.M.; Schulz, T.L.

1993-12-07

A pressurized water nuclear reactor uses its residual heat removal system to make up water in the reactor coolant circuit from an in-containment refueling water supply during staged depressurization leading up to passive emergency cooling by gravity feed from the refueling water storage tank, and flooding of the containment building. When depressurization commences due to inadvertence or a manageable leak, the residual heat removal system is activated manually and prevents flooding of the containment when such action is not necessary. Operation of the passive cooling system is not impaired. A high pressure makeup water storage tank is coupled to the reactor coolant circuit, holding makeup coolant at the operational pressure of the reactor. The staged depressurization system vents the coolant circuit to the containment, thus reducing the supply of makeup coolant. The level of makeup coolant can be sensed to trigger opening of successive depressurization conduits. The residual heat removal pumps move water from the refueling water storage tank into the coolant circuit as the coolant circuit is depressurized, preventing reaching the final depressurization stage unless the makeup coolant level continues to drop. The residual heat removal system can also be coupled in a loop with the refueling water supply tank, for an auxiliary heat removal path. 2 figures.

Residual heat removal system diagnostic advisor

International Nuclear Information System (INIS)

Tripp, L.

1991-01-01

This paper reports on the Residual Heat Removal System (RHRS) Diagnostic Advisor which is an expert system designed to alert the operators to abnormal conditions that exits in the RHRS and offer advice about the cause of the abnormal conditions. The Advisor uses a combination of rule-based and model-based diagnostic techniques to perform its functions. This diagnostic approach leads to a deeper understanding of the RHRS by the Advisor and consequently makes it more robust to unexpected conditions. The main window of the interactive graphic display is a schematic diagram of the RHRS piping system. When a conclusion about a failed component can be reached, the operator can bring up windows that describe the failure mode of the component and a brief explanation about how the Advisor arrived at its conclusion

Software Configuration Management Plan for the Sodium Removal System

International Nuclear Information System (INIS)

HILL, L.F.

2000-01-01

This document establishers the Software Configuration Management Plan (SCMP) for the software associated with the control system of the Sodium Removal System (SRS) located in the Interim Examination and Maintenance (IEM Cell) Facility of the FFTF Flux Test

Pentek metal coating removal system: Baseline report

International Nuclear Information System (INIS)

1997-01-01

The Pentek coating removal technology was tested and is being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU's evaluation of efficiency and cost, this report covers evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The Pentek coating removal system consisted of the ROTO-PEEN Scaler, CORNER-CUTTER reg-sign, and VAC-PAC reg-sign. They are designed to remove coatings from steel, concrete, brick, and wood. The Scaler uses 3M Roto Peen tungsten carbide cutters while the CORNER-CUTTER reg-sign uses solid needles for descaling activities. These hand tools are used with the VAC-PAC reg-sign vacuum system to capture dust and debris as removal of the coating takes place. The safety and health evaluation during the testing demonstration focused on two main areas of exposure: dust and noise. Dust exposure minimal, but noise exposure was significant. Further testing for each exposure is recommended because of the environment where the testing demonstration took place. It is feasible that the dust and noise levels will be higher in an enclosed operating environment of different construction. In addition, other areas of concern found were arm-hand vibration, whole-body, ergonomics, heat stress, tripping hazards, electrical hazards, machine guarding, and lockout/tagout

Usefulness of a clinical scoring system to anticipate difficulty of Norplant removal.

Science.gov (United States)

Blumenthal, P D; Remsburg, R E; Glew, G; McGrath, J A; Gaffikin, L

1995-12-01

Removal of contraceptive implants (e.g. Norplant) is an issue affecting its worldwide acceptability. Reports of difficult, painful removals have resulted in lawsuits and reduced demand. To improve quality of care, we developed a scoring system to anticipate difficult removals. We report on the usefulness of such a system and present client perspectives about the removal experience. A 9-point scoring system based on the visibility, arrangement, and position (VAP) of Norplant capsules was used to assess the anticipated difficulty of removal in 53 consecutive patients. The VAP score was then correlated with removal time and related parameters. Mean removal time was 14.74 min (range 4.75-47). In 20% of patients, the VAP score indicated a potentially difficult removal and the VAP score correlated significantly with removal time (r = 0.3, p = 0.05). Patients expected removal to be moderately difficult (mean visual analog score 4.7 out of a possible 10), but after removal they rated the actual removal experience as relatively easy (mean score 2.6/10). Before the removal, only 48% of patients said they would recommend Norplant to a friend but after removal, 70% said they would do so. A scoring system such as the VAP score can help identify potentially difficult removals so that an experienced remover can be present at the time of removal or an appropriate referral made. However, the VAP score cannot predict variables such as the density of the subcutaneous fibrous tissue "envelope". Although patient anxiety concerning removal may be high, the presence of a competent remover and an easy removal experience reduces this anxiety and encourages patients to be more positive about this method. The value of having properly trained, competent personnel available to perform removals cannot be over-emphasized.

Reducing false positives of microcalcification detection systems by removal of breast arterial calcifications.

Science.gov (United States)

Mordang, Jan-Jurre; Gubern-Mérida, Albert; den Heeten, Gerard; Karssemeijer, Nico

2016-04-01

In the past decades, computer-aided detection (CADe) systems have been developed to aid screening radiologists in the detection of malignant microcalcifications. These systems are useful to avoid perceptual oversights and can increase the radiologists' detection rate. However, due to the high number of false positives marked by these CADe systems, they are not yet suitable as an independent reader. Breast arterial calcifications (BACs) are one of the most frequent false positives marked by CADe systems. In this study, a method is proposed for the elimination of BACs as positive findings. Removal of these false positives will increase the performance of the CADe system in finding malignant microcalcifications. A multistage method is proposed for the removal of BAC findings. The first stage consists of a microcalcification candidate selection, segmentation and grouping of the microcalcifications, and classification to remove obvious false positives. In the second stage, a case-based selection is applied where cases are selected which contain BACs. In the final stage, BACs are removed from the selected cases. The BACs removal stage consists of a GentleBoost classifier trained on microcalcification features describing their shape, topology, and texture. Additionally, novel features are introduced to discriminate BACs from other positive findings. The CADe system was evaluated with and without BACs removal. Here, both systems were applied on a validation set containing 1088 cases of which 95 cases contained malignant microcalcifications. After bootstrapping, free-response receiver operating characteristics and receiver operating characteristics analyses were carried out. Performance between the two systems was compared at 0.98 and 0.95 specificity. At a specificity of 0.98, the sensitivity increased from 37% to 52% and the sensitivity increased from 62% up to 76% at a specificity of 0.95. Partial areas under the curve in the specificity range of 0.8-1.0 were

Operability test procedure [Tank] 241-SY-101 equipment removal system

International Nuclear Information System (INIS)

Mast, J.C.

1994-01-01

The 241-SY-101 equipment removal system (ERS) consists of components, equipment, instrumentation and procedures that will provide the means to disconnect, retrieve, contain, load and transport the Mitigation Pump Assembly (MPA) from waste Tank 241-SY-101 to the Central Waste Complex (CWC). The Operability Test Procedure (OTP) will test the interfaces between ERS components and will rehearse the procedure for MPA removal and transportation to the extent they can be mocked-up at the CTF (Cold Test Facility). At the conclusion of the OTP, the ERS components and equipment will be removed from the CTF, entered into the Component Based Recall System (CBRS), and stored until needed for actual MPA removal and transportation

Residual Heat Removal System qualitative probabilistic safety analysis before and after auto closure interlock removal

International Nuclear Information System (INIS)

Mikulicic, V.; Simic, Z.

1992-01-01

The analysis evaluates the consequences of the removal of the auto closure interlock (ACI) on the Residual Heat Removal System (RHRS) suction/isolation valves at the nuclear power plant. The deletion of the RHRS ACI is in part based on a probabilistic safety analysis (PSA) which justifies the removal based on a criterion of increased availability and reliability. Three different areas to be examined in PSA: the likelihood of an interfacing system LOCA; RHRS availability and reliability; and low temperature overpressurization control. The paper emphasizes particularly the RHRS unavailability and reliability evaluation utilizing the current control circuitry configuration and then with the proposed modification to the control circuitry. (author)

Improvements in iodine and ruthenium removal from advanced liquid processing system

Energy Technology Data Exchange (ETDEWEB)

Skibo, A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-09-27

SRNL has considerable experience in designing, engineering, and operating systems for removing iodine-129 (I-129) and ruthenium-106 (Ru-106) from waste streams that are directly analogous to the Advanced Liquid Processing System (ALPS) waste streams. SRNL proposes to provide the technical background and design and engineering support for an improved I-129 and Ru-106 removal system for application to ALPS on the Fukushima Daiichi Nuclear Power Station (NPS).

Retrofitting of activated charcoal filters in the iodine removal system of Cirus reactor

International Nuclear Information System (INIS)

Arora, M.K.; Thomas, Shibu; Ullas, O.P.; Sharma, V.K.; Singh, Kapil Deo S.

2002-01-01

Full text: The emergency exhaust system for removal of iodine in the 40 MWt Cirus reactor consisted of a caustic scrubber followed by a bank of silver-coated copper mesh filters. The latter filter elements are no longer commercially available, and moreover, there is need to upgrade the system to meet the current safety norms. An iodine removal system based on activated charcoal adsorbers has been selected for this purpose. The design of the system ensures high iodine removal efficiency and thermal safety of the filters for a postulated accident condition beyond design basis accident. The new iodine removal system has been retrofitted during the current refurbishing programme of Cirus and it has been commissioned and tested satisfactorily

Reducing false positives of microcalcification detection systems by removal of breast arterial calcifications

International Nuclear Information System (INIS)

Mordang, Jan-Jurre; Gubern-Mérida, Albert; Karssemeijer, Nico; Heeten, Gerard den

2016-01-01

Purpose: In the past decades, computer-aided detection (CADe) systems have been developed to aid screening radiologists in the detection of malignant microcalcifications. These systems are useful to avoid perceptual oversights and can increase the radiologists’ detection rate. However, due to the high number of false positives marked by these CADe systems, they are not yet suitable as an independent reader. Breast arterial calcifications (BACs) are one of the most frequent false positives marked by CADe systems. In this study, a method is proposed for the elimination of BACs as positive findings. Removal of these false positives will increase the performance of the CADe system in finding malignant microcalcifications. Methods: A multistage method is proposed for the removal of BAC findings. The first stage consists of a microcalcification candidate selection, segmentation and grouping of the microcalcifications, and classification to remove obvious false positives. In the second stage, a case-based selection is applied where cases are selected which contain BACs. In the final stage, BACs are removed from the selected cases. The BACs removal stage consists of a GentleBoost classifier trained on microcalcification features describing their shape, topology, and texture. Additionally, novel features are introduced to discriminate BACs from other positive findings. Results: The CADe system was evaluated with and without BACs removal. Here, both systems were applied on a validation set containing 1088 cases of which 95 cases contained malignant microcalcifications. After bootstrapping, free-response receiver operating characteristics and receiver operating characteristics analyses were carried out. Performance between the two systems was compared at 0.98 and 0.95 specificity. At a specificity of 0.98, the sensitivity increased from 37% to 52% and the sensitivity increased from 62% up to 76% at a specificity of 0.95. Partial areas under the curve in the specificity

Reducing false positives of microcalcification detection systems by removal of breast arterial calcifications

Energy Technology Data Exchange (ETDEWEB)

Mordang, Jan-Jurre, E-mail: Jan-Jurre.Mordang@radboudumc.nl; Gubern-Mérida, Albert; Karssemeijer, Nico [Diagnostic Image Analysis Group, Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen 6525 GA (Netherlands); Heeten, Gerard den [The National Training Centre for Breast Cancer Screening, Nijmegen 6503 GJ, The Netherlands and Department of Radiology, Amsterdam Medical Center, Amsterdam 1100 DD (Netherlands)

2016-04-15

Purpose: In the past decades, computer-aided detection (CADe) systems have been developed to aid screening radiologists in the detection of malignant microcalcifications. These systems are useful to avoid perceptual oversights and can increase the radiologists’ detection rate. However, due to the high number of false positives marked by these CADe systems, they are not yet suitable as an independent reader. Breast arterial calcifications (BACs) are one of the most frequent false positives marked by CADe systems. In this study, a method is proposed for the elimination of BACs as positive findings. Removal of these false positives will increase the performance of the CADe system in finding malignant microcalcifications. Methods: A multistage method is proposed for the removal of BAC findings. The first stage consists of a microcalcification candidate selection, segmentation and grouping of the microcalcifications, and classification to remove obvious false positives. In the second stage, a case-based selection is applied where cases are selected which contain BACs. In the final stage, BACs are removed from the selected cases. The BACs removal stage consists of a GentleBoost classifier trained on microcalcification features describing their shape, topology, and texture. Additionally, novel features are introduced to discriminate BACs from other positive findings. Results: The CADe system was evaluated with and without BACs removal. Here, both systems were applied on a validation set containing 1088 cases of which 95 cases contained malignant microcalcifications. After bootstrapping, free-response receiver operating characteristics and receiver operating characteristics analyses were carried out. Performance between the two systems was compared at 0.98 and 0.95 specificity. At a specificity of 0.98, the sensitivity increased from 37% to 52% and the sensitivity increased from 62% up to 76% at a specificity of 0.95. Partial areas under the curve in the specificity

K basins sludge removal sludge pretreatment system

International Nuclear Information System (INIS)

Chang, H.L.

1997-01-01

The Spent Nuclear Fuels Program is in the process of planning activities to remove spent nuclear fuel and other materials from the 100-K Basins as a remediation effort for clean closure. The 105 K- East and K-West Basins store spent fuel, sludge, and debris. Sludge has accumulated in the 1 00 K Basins as a result of fuel oxidation and a slight amount of general debris being deposited, by settling, in the basin water. The ultimate intent in removing the sludge and fuel is to eliminate the environmental risk posed by storing fuel at the K Basins. The task for this project is to disposition specific constituents of sludge (metallic fuel) to produce a product stream through a pretreatment process that will meet the requirements, including a final particle size acceptable to the Tank Waste Remediation System (TWRS). The purpose of this task is to develop a preconceptual design package for the K Basin sludge pretreatment system. The process equipment/system is at a preconceptual stage, as shown in sketch ES-SNF-01 , while a more refined process system and material/energy balances are ongoing (all sketches are shown in Appendix C). Thus, the overall process and 0535 associated equipment have been conservatively selected and sized, respectively, to establish the cost basis and equipment layout as shown in sketches ES- SNF-02 through 08

After-heat removing system in FBR type reactor

International Nuclear Information System (INIS)

Ohashi, Yukio.

1990-01-01

The after-heat removing system of the present invention removes the after heat generated in a reactor core without using dynamic equipments such as pumps or blowers. There are disposed a first heat exchanger for heating a heat medium by the heat in a reactor container and a second heat exchanger situated above the first heat exchanger for spontaneously air-cooling the heat medium. Recycling pipeways connect the first and the second heat exchangers to form a recycling path for the heat medium. Then, since the second heat exchanger for spontaneously air-cooling the heat medium is disposed above the first heat exchanger and they are connected by the recycling pipeways, the heat medium can be circulated spontaneously. Accordingly, dynamic equipments such as pumps or blowers are no more necessary. As a result, the after-heat removing system of the FBR type reactor of excellent safety and reliability can be obtained. (I.S.)

Boron Removal in Seawater Reverse Osmosis System

KAUST Repository

Rahmawati, Karina

2011-07-01

Reverse osmosis successfully proves to remove more than 99% of solute in seawater, providing fresh water supply with satisfied quality. Due to some operational constraints, however, some trace contaminants removal, such as boron, cannot be achieved in one pass system. The stringent criterion for boron from World Health Organization (WHO) and Saudi Arabia local standard (0.5 mg/l) is hardly fulfilled by single pass sea water reverse osmosis (SWRO) plants. Some design processes have been proposed to deal with boron removal, but they are not economically efficient due to high energy and chemical consumption. The objective of this study was to study boron removal by different reverse osmosis membranes in two pH conditions, with and without antiscalant addition. Thus, it was expected to observe the possibility of operating single pass system and necessity to operate two pass system using low energy membrane. Five membrane samples were obtained from two different manufacturers. Three types of feed water pH were used, pH 8, pH 10, and pH 10 with antiscalant addition. Experiment was conducted in parallel to compare membrane performance from two manufacturers. Filtration was run with fully recycle mode for three days. Sample of permeate and feed were taken every 12 hours, and analyzed for their boron and TDS concentration. Membrane samples were also tested for their surface charge. The results showed that boron rejection increases as the feed pH increases. This was caused by dissociation of boric acid to negatively charged borate ion and more negatively charged membrane surface at elevated pH which enhance boron rejection. This study found that single pass reverse osmosis system, with and without elevating the pH, may not be possible to be applied because of two reasons. First, permeate quality in term of boron, does not fulfill WHO and local Saudi Arabia regulations. Second, severe scaling occurs due to operation in alkaline condition, since Ca and Mg concentration are

Simultaneous biological nutrient removal: evaluation of autotrophic denitrification, heterotrophic nitrification, and biological phosphorus removal in full-scale systems.

Science.gov (United States)

Littleton, Helen X; Daigger, Glen T; Strom, Peter F; Cowan, Robert A

2003-01-01

Simultaneous biological nutrient removal (SBNR) is the biological removal of nitrogen and phosphorus in excess of that required for biomass synthesis in a biological wastewater treatment system without defined anaerobic or anoxic zones. Evidence is growing that significant SBNR can occur in many systems, including the aerobic zone of systems already configured for biological nutrient removal. Although SBNR systems offer several potential advantages, they cannot be fully realized until the mechanisms responsible for SBNR are better understood. Consequently, a research program was initiated with the basic hypothesis that three mechanisms might be responsible for SBNR: the reactor macroenvironment, the floc microenvironment, and novel microorganisms. Previously, the nutrient removal capabilities of seven full-scale, staged, closed-loop bioreactors known as Orbal oxidation ditches were evaluated. Chemical analysis and microbiological observations suggested that SBNR occurred in these systems. Three of these plants were further examined in this research to evaluate the importance of novel microorganisms, especially for nitrogen removal. A screening tool was developed to determine the relative significance of the activities of microorganisms capable of autotrophic denitrification and heterotrophic nitrification-aerobic denitrification in biological nutrient removal systems. The results indicated that novel microorganisms were not substantial contributors to SBNR in the plants studied. Phosphorus metabolism (anaerobic release, aerobic uptake) was also tested in one of the plants. Activity within the mixed liquor that was consistent with current theories for phosphorus-accumulating organisms (PAOs) was observed. Along with other observations, this suggests the presence of PAOs in the facilities studied.

Nitrogen removal and nitrate leaching for forage systems receiving dairy effluent.

Science.gov (United States)

Woodard, Kenneth R; French, Edwin C; Sweat, Lewin A; Graetz, Donald A; Sollenberger, Lynn E; Macoon, Bisoondat; Portier, Kenneth M; Wade, Brett L; Rymph, Stuart J; Prine, Gordon M; Van Horn, Harold H

2002-01-01

Florida dairies need year-round forage systems that prevent loss of N to ground water from waste effluent sprayfields. Our purpose was to quantify forage N removal and monitor nitrate N (NO3(-)-N) concentrations in soil water below the rooting zone for two forage systems during four 12-mo cycles (1996-2000). Soil in the sprayfield is an excessively drained Kershaw sand (thermic, uncoated Typic Quartzipsamment). Over four cycles, average loading rates of effluent N were 500, 690, and 910 kg ha(-1) per cycle. Nitrogen removed by the bermudagrass (Cynodon spp.)-rye (Secale cereale L.) system (BR) during the first three cycles was 465 kg ha(-1) per cycle for the low loading rate, 528 kg ha(-1) for the medium rate, and 585 kg ha(-1) for the high. For the corn (Zea mays L.)-forage sorghum [Sorghum bicolor (L.) Moench]-rye system (CSR), N removals were 320 kg ha(-1) per cycle for the low rate, 327 kg ha(-1) for the medium, and 378 kg ha(-1) for the high. The higher N removals for BR were attributed to higher N concentration in bermudagrass (18.1-24.2 g kg(-1)) than in corn and forage sorghum (10.3-14.7 g kg(-1)). Dry matter yield declined in the fourth cycle for bermudagrass but N removal continued to be higher for BR than CSR. The BR system was much more effective at preventing NO3(-)-N leaching. For CSR, NO3(-)-N levels in soil water (1.5 m below surface) increased steeply during the period between the harvest of one forage and canopy dosure of the next. Overall, the BR system was better than CSR at removing N from the soil and maintaining low NO3(-)-N concentrations below the rooting zone.

Evaluation of Heat Removal Performance of Passive Decay Heat Removal system for S-CO{sub 2} Cooled Micro Modular Reactor

Energy Technology Data Exchange (ETDEWEB)

Moon, Jangsik; Lee, Jeong Ik; Jeong, Yong Hoon [KAIST, Daejeon (Korea, Republic of)

2015-05-15

The modular systems is able to be transported by large trailer. Moreover, dry cooling system is applied for waste heat removal. The characteristics of MMR takes wide range of construction area from coast to desert, isolated area and disaster area. In MMR, Passive decay heat removal system (PDHRS) is necessary for taking the advantage on selection of construction area where external support cannot be offered. The PDHRS guarantees to protect MMR without external support. In this research, PDHRS of MMR is introduced and decay heat removal performance is analyzed. The PDHRS guarantees integrity of reactor coolant system. The high level of decay heat (2 MW) can be removed by PDHRS without offsite power.

High-efficiency SO2 removal in utility FGD systems

International Nuclear Information System (INIS)

Phillips, J.L.; Gray, S.; Dekraker, D.

1995-01-01

The U.S. Department of Energy (DOE) and the Electric Power Research Institute (EPRI) have contracted with Radian Corporation to conduct full-scale testing, process modeling, and economic evaluations of six existing utility flue gas desulfurization (FGD) systems. The project objective is to evaluate low capital cost upgrades for achieving up to 98% sulfur dioxide (SO 2 ) removal efficiency in a variety of FGD system types. The systems include dual-loop, packed absorbers at Tampa Electric Company's Big Bend Station; cocurrent, packed absorbers at Hoosier Energy's Merom Station; dual-loop absorbers with perforated-plate trays at Southwestern Electric Power Company's Pirkey Station; horizontal spray absorbers at PSI Energy's Gibson Station; venturi scrubbers at Duquesne Light's Elrama Station; and open stray absorbers at New york State Electric and Gas Corporations's (NYSEG's) Kintigh Station. All operate in an inhibited-oxidation mode except the system at Big Bend (forced oxidation), and all use limestone reagent except the Elrama system (Mg-lime). The program was conducted to demonstrate that upgrades such as performance additives and/or mechanical modifications can increase system SO 2 removal at low cost. The cost effectiveness of each upgrade has been evaluated on the basis of test results and/or process model predictions for upgraded performance and utility-specific operating and maintenance costs. Results from this upgraded performance and utility-specific operating and maintenance costs. Results from this program may lead some utilities to use SO 2 removal upgrades as an approach for compliance with phase 2 of Title IV of the Clean Air Act Amendments (CAAA) of 1990. This paper summarizes the results of testing, modeling, and economic evaluations that have been completed since July, 1994

Simplified analysis of passive residual heat removal systems for small size PWR's

International Nuclear Information System (INIS)

Botelho, D.A.

1992-02-01

The function and general objectives of a passive residual heat removal system for small size PWR's are defined. The characteristic configuration, the components and the operation modes of this system are concisely described. A preliminary conceptual specification of this system, for a small size PWR of 400 MW thermal, is made analogous to the decay heat removal system of the AP-600 reactor. It is shown by analytic models that such passive systems can dissipate 2% of nominal power within the thermal limits allowed to the reactor fuel elements. (author)

BOA II: Asbestos Pipe-Insulation Removal Robot System. Innovative Technology Summary Report

International Nuclear Information System (INIS)

None

2001-01-01

The objective of this task is to develop and demonstrate a mechanical, asbestos-removal system that can be remotely operated without a containment area. The technology, known as BOA, consists of a pipe-crawler removal head and a boom vehicle system with dual robots. BOA's removal head can be remotely placed on the outside of the pipe and can crawl along the pipe, removing lagging and insulation. The lagging and insulation is cut using a hybrid endmill water-jet cutter and then diced into 2-inch cube sections of ACM. These ACM sections are then removed from the pipe using a set of blasting fan- spray nozzles, vacuumed off through a vacuum hose, and bagged. Careful attention to vacuum and entrapment air flow ensures that the system can operate without a containment area while meeting local and federal standards for fiber count

Development of metal catalyst impregnation technology for membrane-based oxygen removal system

International Nuclear Information System (INIS)

Kim, Mun Soo; Lee, Doo Ho; Kang, Duk Won

2005-01-01

Dissolved oxygen(DO) is a primary cause of PWSCC and its content in reactor coolant system in NPPs has been strictly controlled by various DO removal methods. There are several removal methods of DO, such as vacuum degasification, thermal deaeration, and reductive removal by oxygen scavengers. Although the operation principles of vacuum degasification and thermal deaeration are simple, these methods require a lot of energy for operation and show lower efficiency. And these methods have a few handicaps such as temperature, pH, toxicity, high cost of installation and so on. For the purpose of developing the best method for DO removal from make-up water storage tank, it is necessary to overcome the disadvantages of hydrazine treatment. From this point of view, membrane-based oxygen removal system (MORS) has many advantages than other methods for example, friendly environmental process, versatility of operation conditions with high temperature and low pressure, small space, low cost, etc. Recently de-gassing membrane is widely used in power plant's feed water system for DO removal. De-gassing membrane has some advantages; it removes other dissolved gases such as CO2, N2, as well as O2, and is more economical than Catalytic resin-based Oxygen Removal System. In this study, to obtain better efficiency of MORS, we modified the polypropylene (PP) hollow fiber membrane by plasma treatment and ion beam irradiation supported platinum(Pt), palladium(Pd) as metal catalyst on the surface of the membrane

A decay heat removal system requiring no external energy

International Nuclear Information System (INIS)

Costes, D.; Fermandjian, J.

1983-12-01

A new Decay heat Removal System is described for PWR's with dry containment, i.e. a containment building which encloses no permanent reserve of cooling water. This new system is intended to provide a high level of safety since it uses no external energy, but only the thermodynamic energy of the air-steam-liquid water mixture generated in the containment after the failure of the primary circuit (''LOCA'') or of the secondary circuit. Thermodynamics of the system is evaluated first: after some design considerations, the use of the system for protecting actual PWR's is addressed

Nitrogen removal and microbial communities in a three-stage system simulating a riparian environment.

Science.gov (United States)

Wang, Ziyuan; Wang, Zhixin; Pei, Yuansheng

2014-06-01

The riparian zone is an active interface for nitrogen removal, in which nitrogen transformations by microorganisms have not been valued. In this study, a three-stage system was constructed to simulate the riparian zone environments, and nitrogen removal as well as the microbial community was investigated in this 'engineered riparian system'. The results demonstrated that stage 1 of this system accounted for 41-51 % of total nitrogen removal. Initial ammonium loading and redox potential significantly impacted the nitrogen removal performances. Stages 1 and 2 were both composed of an anoxic/oxic (A/O) zone and an anaerobic column. The A/O zone removed most of the ammonium load (6.8 g/m(2)/day), while the anaerobic column showed a significant nitrate removal rate (11.1 g/m(2)/day). Molecular biological analysis demonstrated that bacterial diversity was high in the A/O zones, where ammonium-oxidizing bacteria and nitrite-oxidizing bacteria accounted for 8.42 and 3.32 % of the bacterial population, respectively. The denitrifying bacteria Acidovorax sp. and the nitrifying bacteria Nitrosospira/Nitrosomonas were the predominant microorganisms in this engineered riparian system. This three-stage system was established to achieve favorable nitrogen removal and the microbial community in the system was also retained. This investigation should deepen our understanding of biological nitrogen removal in engineered riparian zones.

Design and analysis of a new passive residual heat removal system

Energy Technology Data Exchange (ETDEWEB)

Lv, Xing [Key Subject Laboratory of Nuclear Safety and Simulation Technology, Harbin Engineering University, Harbin, Heilongjiang 150001 (China); Peng, Minjun, E-mail: heupmj@163.com [Key Subject Laboratory of Nuclear Safety and Simulation Technology, Harbin Engineering University, Harbin, Heilongjiang 150001 (China); Yuan, Xiao [Guangxi Fangchenggang Nuclear Power Co., Ltd (China); Xia, Genglei [Key Subject Laboratory of Nuclear Safety and Simulation Technology, Harbin Engineering University, Harbin, Heilongjiang 150001 (China)

2016-07-15

Highlights: • An air cooling passive residual heat removal System (PRHRs) is designed. • Using RELAP5/MOD3.4 code to analyze the operation characteristics of the PRHRs. • Noncondensable gas is used to simulate the hydrodynamic behavior in the air cooling tower. • The natural circulations could respectively establish in the primary circuit and the PRHRs circuit. • The PRHRs could remove the residual heat effectively. - Abstract: The inherent safety functions will mitigate the consequences of the accidents, and it can be accomplished through the passive safety systems which employed in the typical pressurized water reactor (PWR). In this paper, a new passive residual heat removal system (PRHRS) is designed for a typical nuclear power plant. PRHRS consists of a steam generator (SG), a cooling tank with two groups of cooling pipes, an air-cooling heat exchanger (AHX), an air-cooling tower, corresponding pipes and valves. The cooling tank which works as an intermediate buffer device is used to transfer the core decay heat to the AHX, and then the core decay heat will be removed to the atmosphere finally. The RELAP5/MOD3.4 code is used to analyze the operation characteristics of PRHRS and the primary loop system. It shows PRHRS could remove the decay heat from the primary loop effectively, and the natural circulations can be established in the primary circuit and the PRHRS circuit respectively. Furthermore, the sensitivity study has also been done to research the effect of various factors on the heat removal capacity.

Valve arrangement for a nuclear plant residual heat removal system

International Nuclear Information System (INIS)

Fidler, G.L.; Hill, R.A.; Carrera, J.P.

1978-01-01

Disclosed is an improved valve arrangement for a two-train Residual Heat Removal System (RHRS) of a nuclear reactor plant which ensures operational integrity of the system under single failure circumstances including loss of one of two electrical power sources

Summary report for Group X6: Heat removal system and system analysis

Energy Technology Data Exchange (ETDEWEB)

Leung, W

2005-12-15

This report is a summary of the activities of the X6 design support for the Heat Removal System (HRS) of MEGAPIE. It can be divided into two main parts: The first part is about the design and manufacturing of he cooling loop (the first 3 chapters), and the second part is dealing with the thermal hydraulic analysis of the overall HRS. This also reflects the change of the X6 activities from design to operation support. The activities of this group are more or less driven by the needs rather than a complete set of tasks given at the start of the project. The first part chronicles the system development. Some of the arguments are probably outdated but are kept in the original form to illustrate the evolution of concepts. The main objective is, of course, to design a heat removal system that can cool the liquid metal spallation target for a 1 MW proton beam i.e. 1.74 mA in 575 MeV). It is also reckoned that the liquid metal, BE (lead-bismuth-eutectic), must be kept liquid even when the proton beam was switched off. This requires either that the cooling system can be shut down or the operating temperature of the coolant be higher than the freezing point of LBE. As for safety concerns, the HRS system must not exert a pressure that exceeds the design pressure of the target beam window in case of a break at the target heat exchanger (THX); this limits the cover gas pressure to about 4 bar(a). These are the basic design principles that carry through the conceptual and engineering design of he system. The organic coolant Diphyl THT was then chosen, because of its wide range of operating temperature (i.e. from 0 to 340 degC) and high boiling point, and a proven record in industrial applications. (author)

Summary report for Group X6: Heat removal system and system analysis

International Nuclear Information System (INIS)

Leung, W.

2005-12-01

This report is a summary of the activities of the X6 design support for the Heat Removal System (HRS) of MEGAPIE. It can be divided into two main parts: The first part is about the design and manufacturing of he cooling loop (the first 3 chapters), and the second part is dealing with the thermal hydraulic analysis of the overall HRS. This also reflects the change of the X6 activities from design to operation support. The activities of this group are more or less driven by the needs rather than a complete set of tasks given at the start of the project. The first part chronicles the system development. Some of the arguments are probably outdated but are kept in the original form to illustrate the evolution of concepts. The main objective is, of course, to design a heat removal system that can cool the liquid metal spallation target for a 1 MW proton beam i.e. 1.74 mA in 575 MeV). It is also reckoned that the liquid metal, BE (lead-bismuth-eutectic), must be kept liquid even when the proton beam was switched off. This requires either that the cooling system can be shut down or the operating temperature of the coolant be higher than the freezing point of LBE. As for safety concerns, the HRS system must not exert a pressure that exceeds the design pressure of the target beam window in case of a break at the target heat exchanger (THX); this limits the cover gas pressure to about 4 bar(a). These are the basic design principles that carry through the conceptual and engineering design of he system. The organic coolant Diphyl THT was then chosen, because of its wide range of operating temperature (i.e. from 0 to 340 degC) and high boiling point, and a proven record in industrial applications. (author)

Designing Bioretention Systems to Improve Nitrogen Removal - poster

Science.gov (United States)

Rain gardens, also referred to as bioretention systems, are designed primarily to infiltrate stormwater flow and reduce surface runoff and peak flows to receiving streams. Additionally, they are known to remove stressors from urban stormwater runoff, including oil and grease, pho...

Removal of pharmaceuticals and personal care products in aquatic plant-based systems: A review

International Nuclear Information System (INIS)

Zhang, Dongqing; Gersberg, Richard M.; Ng, Wun Jern; Tan, Soon Keat

2014-01-01

Pharmaceuticals and personal care products (PPCPs) in the aquatic environment are regarded as emerging contaminants and have attracted increasing concern. The use of aquatic plant-based systems such as constructed wetlands (CWs) for treatment of conventional pollutants has been well documented. However, available research studies on aquatic plant-based systems for PPCP removal are still limited. The removal of PPCPs in CWs often involves a diverse and complex set of physical, chemical and biological processes, which can be affected by the design and operational parameters selected for treatment. This review summarizes the PPCP removal performance in different aquatic plant-based systems. We also review the recent progress made towards a better understanding of the various mechanisms and pathways of PPCP attenuation during such phytoremediation. Additionally, the effect of key CW design characteristics and their interaction with the physico-chemical parameters that may influence the removal of PPCPs in functioning aquatic plant-based systems is discussed. -- Highlights: • Investigation of the removal performance of PPCPs in CW systems. • Investigation of the mechanisms and pathways contributing to PPCP removal in CWs. • Investigation of the effect of CW design parameters on PPCP removal. • Investigation of the correlation between physico-chemical parameters and PPCP removal. -- This review gives an overview of the present state of research on the removal of pharmaceutical and personal care products by means of constructed wetlands

Experiences with on line fault detection system for protection system logic and decay heat removal system logic in Dhruva

International Nuclear Information System (INIS)

Ramkumar, N.; Dutta, P.K.; Darbhe, M.D.; Bharadwaj, G.

2001-01-01

Dhruva is a 100 MW (Thermal) natural uranium fuelled, vertical core, tank type multi purpose research reactor with heavy water acting as moderator, coolant and reflector. Helium is used as cover gas for heavy water system. Reactor Protection System and Decay Heat Removal System (DHRS) have triplicated instrumented channels. The logic for these systems are hybrid in nature with a mixture of relay logic and solid state logic. Fine Impulse Technique(FIT) is employed for On-line fault detection in the solid state logics of these systems. The FIT systems were designed in the early eighties. Operating experiences over the past 15 years has revealed certain deficiencies. In view of this, a microcomputer based state of the art FIT systems for logics of Reactor Protection System and DHRS are being implemented with improved functionalities built into them. This paper describes the operating experience of old FIT systems and improved features of the proposed new FIT systems. (author)

Removing radio-active wastes from nuclear power stations by the STEAG system

International Nuclear Information System (INIS)

Baatz, H.

1978-01-01

The mobile STEAG System for conditioning radio-active wastes from nuclear power stations represents a particularly safe and economic method of removing them in present day conditions. Cementation by the FAFNIR System is used for the greater part of the waste, the liquid concentrate (evaporator concentrate and filter slurry). For the special case of the medium active resin balls from the primary circuits, embedding in plastic by the FAMA process has proved to be the only available successful process so far. The highly active solid waste from the reactor core is decomposed by the MOSAIK System, is packed in transportable and storable containers and is removed from the fuel element storage pond. The systems are so safe that faults or interruptions of power station operation due to faults in removing radio-active wastes can be excluded. (orig.) [de

Excessive heat removal due to feedwater system malfunction

International Nuclear Information System (INIS)

Beader, D.; Peterlin, G.

1986-01-01

Excessive heat removal transient of the Krsko Nuclear Power Plant, caused by steam generators feedwater system malfunctions was simulated by RELAP5/MOD1 computer code. The results are increase of power and reactor scram caused by high-high steam generator level. (author)

Removal of CO2 in closed loop off-gas treatment systems

International Nuclear Information System (INIS)

Clemens, M.K.; Nelson, P.A.; Swift, W.M.

1994-01-01

A closed loop test system has been installed at Argonne National Laboratory (ANL) to demonstrate off-gas treatment, absorption, and purification systems to be used for incineration and vitrification of hazardous and mixed waste. Closed loop systems can virtually eliminate the potential for release of hazardous or toxic materials to the atmosphere during both normal and upset conditions. In initial tests, a 250,000 Btu/h (75 kW thermal) combustor was operated in an open loop to produce a combustion product gas. The CO 2 in these tests was removed by reaction with a fluidized bed of time to produce CaCO 3 . Subsequently, recirculation system was installed to allow closed loop operation with the addition of oxygen to the recycle stream to support combustion. Commercially marketed technologies for removal of CO 2 can be adapted for use on closed loop incineration systems. The paper also describes the Absorbent Solution Treatment (AST) process, based on modifications to commercially demonstrated gas purification technologies. In this process, a side loop system is added to the main loop for removing CO 2 in scrubbing towers using aqueous-based CO 2 absorbents. The remaining gas is returned to the incinerator with oxygen addition. The absorbent is regenerated by driving off the CO 2 and water vapor, which are released to the atmosphere. Contaminants are either recycled for further treatment or form precipitates which are removed during the purification and regeneration process. There are no direct releases of gases or particulates to the environment. The CO 2 and water vapor go through two changes of state before release, effectively separating these combustion products from contaminants released during incineration. The AST process can accept a wide range of waste streams. The system may be retrofitted to existing Facilities or included in the designs for new installations

A passive decay heat removal system for LWRs based on air cooling

Energy Technology Data Exchange (ETDEWEB)

Mochizuki, Hiroyasu, E-mail: mochizki@u-fukui.ac.jp [Research Institute of Nuclear Engineering, University of Fukui, 1-2-4 Kanawa-cho, Tsuruga, Fukui 914-0055 (Japan); Yano, Takahiro [Graduate School of Engineering, University of Fukui, 1-2-4 Kanawa-cho, Tsuruga, Fukui 914-0055 (Japan)

2015-05-15

Highlights: • A passive decay heat removal system for LWRs is discussed. • An air cooler model which condenses steam is developed. • The decay heat can be removed by air coolers with forced convection. • The dimensions of the air cooler are proposed. - Abstract: The present paper describes the capability of an air cooling system (ACS) to remove decay heat from a core of LWR such as an advanced boiling water reactor (ABWR) and a pressurized water reactor (PWR). The motivation of the present research is the Fukushima severe accident (SA) on 11 March 2011. Since emergency cooling systems using electricity were not available due to station blackout (SBO) and malfunctions, many engineers might understand that water cooling was not completely reliable. Therefore, a passive decay heat removal (DHR) system would be proposed in order to prevent such an SA under the conditions of an SBO event. The plant behaviors during the SBO are calculated using the system code NETFLOW++ for the ABWR and PWR with the ACS. Two types of air coolers (ACs) are applied for the ABWR, i.e., a steam condensing air cooler (SCAC) of which intake for heat transfer tubes is provided in the steam region, and single-phase type of which intake is provided in the water region. The DHR characteristics are calculated under the conditions of the forced air circulation and also the natural air convection. As a result of the calculations, the decay heat can be removed safely by the reasonably sized ACS when heat transfer tubes are cooled with the forced air circulation. The heat removal rate per one finned heat transfer tube is evaluated as a function of air flow rate. The heat removal rate increases as a function of the air flow rate.

Electrochemical filtration for turbidity removal in industrial cooling/process water systems

International Nuclear Information System (INIS)

Kumbhar, A.G.; Venkateswaran, G.

2008-01-01

Water samples of large cooling water reservoirs may look visibly clear and transparent, but still may contain sub-micron size particles at sub-parts-per-million levels. Deposition of these particles on heat exchanger surfaces, reduces the heat transfer efficiency in power industry. In nuclear power plants, additionally it creates radiation exposure problems due to activation of fine metallic turbidity in the reactor core and its subsequent transfer to out-of-core surfaces. Sub-micron filtration creates back high-pressure problem. Zeta filters available commercially are prescribed for separating either positively or negatively charged particles. They are of once-use and throw-type. Precipitation surface modified ion exchangers impart chemical impurities to the system. Thus, sub-micron size and dilute turbidity removal from large volumes of waters such as heat exchanger cooling water in nuclear and power industry poses a problem. Electro deposition of the turbidity causing particles, on porous carbon/graphite felt electrodes, is one of the best suited methods for turbidity removal from large volumes of water due to the filter's high permeability, inertness to the system and regenerability resulting in low waste generation. Initially, active indium turbidity removal from RAPS-1 heavy water moderator system, and microbes removal from heat exchanger cooling lake water of RAPS 1 and 2 were demonstrated with in-house designed and fabricated prototype electrochemical filter (ECF). Subsequently, a larger size, high flow filter was fabricated and deployed for iron turbidity removal from active process waters system of Kaiga Generation Station unit 1 and silica and iron turbidity removal from cooling water pond used for heat exchanger of a high temperature high pressure (HTHP) loop at WSCD, Kalpakkam. The ECF proved its exclusive utility for sub-micron size turbidity removal and microbes removal. ECF maneuverability with potential and current for both positively and

Shutdown risk analysis for a BWR plant (residual heat removal systems)

International Nuclear Information System (INIS)

Rebollo Garcia, C.; Merino Teillet, A.; Cerezo, L.

1994-01-01

This report analyses the different risk situations which may arise during refuelling outage at Cofrentes NPP. The most critical situations are determined in terms of the small amount of coolant available and the lowest number of heat removal and water make-up systems available. The available times before the boiling point of the coolant is reached and the subsequent moment when the fuel elements are left uncovered in the event of the failure of the normal heat removal functions are determined. The analysis identifies the alternative systems which can be used besides those required by the technical specification and their capacity for residual heat removal and coolant make-up functions. (Author)

Organic Removal Efficiency of the Nanofiltration and Adsorption Hybrid System in High Strength Wastewater

Directory of Open Access Journals (Sweden)

Amir Hessam Hassani

2011-03-01

Full Text Available Surface and groundwater resources are increasingly jeopardized by discharges from pharmaceutical, chemical, and detergent plants. The high pollutant load of the effluents from these industries requires specific treatments. The objective of this research was to study and compare the nanofiltration and adsorption hybrid system with the plain nanofiltration system in wastewater treatment.For this purpose, a pilot nanofiltration system with a capacity of 7.6 m3/d using 1 and 5 micron filters and a FILMTEC NF90-4040 membrane was used in the first phase of the study. In the second phase, granular activated carbon cartridges were used. Inluent and effluent discharges as well as the COD removal were measured in both systems under variable times and organic load conditions. The results showed that COD removal efficiency was higher in the hybrid system than in the plain naonofiltration one. In the hybrid system, the Maximum in the hybrid system, the COD removal efficiencies achieved for organic loads of 1000, 2000, and 3000 mg/L were 99%, 95.86%, and 92.93%, respectively. The same values for the plain nanofiltration system were 87.34%, 50%, and 29.41%, respectively. It was found that polarization and membrane fouling decreased both the effluent flow and the COD removal efficiency with time. Fouling of the membrane was, however, lower in the hybrid system compared to the plain nanofiltration; thus, the hybrid system was associated with higher values of COD removal and delayed membrane fouling.

ASBESTOS PIPE-INSULATION REMOVAL ROBOT SYSTEM; FINAL

International Nuclear Information System (INIS)

Unknown

2000-01-01

This final topical report details the development, experimentation and field-testing activities for a robotic asbestos pipe-insulation removal robot system developed for use within the DOE's weapon complex as part of their ER and WM program, as well as in industrial abatement. The engineering development, regulatory compliance, cost-benefit and field-trial experiences gathered through this program are summarized

Can a safeguards accountancy system really detect an unauthorized removal

International Nuclear Information System (INIS)

Ehinger, M.H.; Ellis, J.H.

1981-11-01

Theoretical investigations and system studies indicate safeguards material balance data from reprocessing plants can be used to detect unauthorized removals. Plant systems have been modeled and simulated data used to demonstrate the techniques. But how sensitive are the techniques when used with actual plant data. What is the effect of safeguards applications on plant operability. Can safeguards be acceptable to plant operators, and are there any benefits to be derived. The Barnwell Nuclear Fuel Plant (BNFP) has been devoted to answering these and other questions over the past several years. A computerized system of near-real-time accounting and in-process inventory has been implemented and demonstrated during actual plant test runs. Measured inventories and hourly material balance closures have been made to assess safeguards in an operating plant application. The tests have culminated in actual removals of material from the operating plant to investigate the response and measure the sensitivity of the safeguards and data evaluation system

Study on decay heat removal capability of reactor vessel auxiliary cooling system

International Nuclear Information System (INIS)

Nishi, Y.; Kinoshita, I.

1991-01-01

The reactor vessel auxiliary cooling system (RVACS) is a simple, Passive decay heat removal system for an LMFBR. However, the heat removal capacity of this system is small compared to that of an immersed type of decay heat exchanger. In this study, a high-porosity porous body is proposed to enhance the RVACS's heat transfer performance to improve its applicability. The objectives of this study are to propose a new method which is able to use thermal radiation effectively, to confirm its heat removal capability and to estimate its applicability limit of RVACS for an LMFBR. Heat transfer tests were conducted in an experimental facility with a 3.5 m heat transfer height to evaluate the heat transfer performance of the high-porosity porous body. Using the experimental results, plant transient analyses were performed for a 300 MWe pool type LMFBR under a Total Black Out (TBO) condition to confirm the heat removal capability. Furthermore, the relationship between heat removal capability and thermal output of a reactor were evaluated using a simple parameter model

Removal of an acid fume system contaminated with perchlorates located within hot cell

International Nuclear Information System (INIS)

Rosenberg, K.E.; Henslee, S.P.; Vroman, W.R.; Krsul, J.R.; Michelbacher, J.A.; Knighton, G.C.

1992-09-01

An add scrubbing system located within the confines of a highly radioactive hot cell at Argonne National Laboratory-West (ANL-W) was remotely removed. The acid scrubbing system was routinely used for the dissolution of irradiated reactor fuel samples and structural materials. Perchloric acid was one of the acids used in the dissolution process and remained in the system with its inherent risks. Personnel could not enter the hot cell to perform the dismantling of the acid scabbing system due to the high radiation field and the explosion potential associated with the perchlorates. A robot was designed and built at ANL-W and used to dismantle the system without the need for personnel entry into the hot cell. The robot was also used for size reduction of removed components and loading of the removed components into waste containers

Pre-Conceptual Design for Northstar ⁹⁹Mo Process Tritium Removal System

Energy Technology Data Exchange (ETDEWEB)

Nobile, Arthur [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reichert, Heidi [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hollis, William Kirk [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Taylor, Craig Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gordon, John Cameron [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dale, Gregory E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-01-12

In this report we describe a preliminary concept for a Tritium Removal System (TRS) to remove tritium that is generated in the ⁹⁹Mo production process. Preliminary calculations have been performed to evaluate an approximate size for the system. The concept described utilizes well-established detritiation technology based on catalytic oxidation of tritium and tritiated hydrocarbons to water in a high temperature (400 °C) reactor and capture of water in a molecular sieve bed. The TRS concept involves use of a single system that would cycle through each of the seven online target systems and remove tritium that has been accumulated after one week’s run time. The TRS would perform cleanup operations on each target system for a period of approximately 24 hours. This would occur while the system is still online and just prior to target replacement, so tritium levels would at their minimum values for target replacement. In the concept, during normal operation a small fraction (1%) of the helium recirculating in the system would be diverted through the TRS and returned to the flow loop. With this approach sufficient levels of detritiation can be accomplished in a 24 hour period. In the study it was found that because of the need to maintain low oxygen levels in the system (<100 ppm) this increases the size of the catalytic reactor. As a result of this finding, consideration should be given to other methods for removing tritium from the system. Other methods such as catalytic exchange of tritium with an unsaturated organic compound and subsequent trapping on activated carbon or molecular sieve could offer advantages of reducing reactor size and operation at lower reactor temperature. However the most significant advantage of such an approach would be the ability to operate in very low oxygen environments, which would eliminate any concerns for oxidation of the target.

Waste removal systems and recycling participation in residential environments

DEFF Research Database (Denmark)

Thøgersen, John

2002-01-01

Systems for the removal of waste are important although often overlooked elements of any residential environment. It is an old insight that when these systems are ineffective (and this is globally and historically the rule rather than the exception), human living conditions and often even human...... health are severely impaired (Pieters, 1989). More recently, resource waste and environmental hazards from waste have given rise to public and political concern as well, even when disposal systems are well managed. This concern has led to efforts to divert solid waste away from disposal and towards some...

Pegasus International, Inc. coating removal systems

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-02-01

The Pegasus Coating Removal System (PCRS) was demonstrated at Florida International University (FIU) where it was being evaluated for efficiency and cost. In conjunction with the FIU testing demonstration, a human factors assessment was conducted to assess the hazards and associated safety and health issues of concern for workers utilizing this technology. The PCRS is a chemical paste that is applied to the surface using a brush, roller, or airless sprayer. After the type of PCRS, thickness, and dwell time have been determined, a laminated backed material is placed on top of the chemical paste to slow down the drying process and to provide a mechanism to strip-off the chemical. After the dwell time is reached, the chemical substrate can be removed. Scrapers may be used to break-loose the layers as necessary or to break-loose the layers that are not removed when the laminated paper is picked up. Residue may also be cleaned off of the surface with a damp sponge with an agitating motion, absorbent sponges, or a vacuum, as needed. The paint and removal agent is then placed in drums for disposal at a later time. During the assessment sampling was conducted for organic vapors and general observational techniques were conducted for ergonomics. Recommendations for improved worker safety and health during application and removal of the PCRS include: (1) work practices that reflect avoidance of exposure or reducing the risk of exposure; (2) assuring all PPE and equipment are compatible with the chemicals being used; (3) work practices that reduce the worker`s need to walk on the slippery surface caused by the chemical or the use of special anti-slip soles; (4) careful control of overspray (if a spray application is used); and (5) the use of ergonomically designed long-handled tools to apply and remove the chemical (to alleviate some of the ergonomic concerns).

CPP-603 Chloride Removal System Decontamination and Decommissioning

International Nuclear Information System (INIS)

Moser, C.L.

1993-02-01

The CPP-603 (annex) Chloride Removal System (CRS) Decontamination and Decommissioning (D ampersand D) Project is described in this report. The CRS was used for removing Chloride ions and other contaminants that were suspended in the waters of the underwater fuel storage basins in the CPP-603 Fuel Receiving and Storage Facility (FRSF) from 1975 to 1981. The Environmental Checklist and related documents, facility characterization, decision analysis', and D ampersand D plans' were prepared in 1991. Physical D ampersand D activities were begun in mid summer of 1992 and were completed by the end of November 1992. All process equipment and electrical equipment were removed from the annex following accepted asbestos and radiological contamination removal practices. The D ampersand D activities were performed in a manner such that no radiological health or safety hazard to the public or to personnel at the Idaho National Engineering Laboratory (INEL) occurred

Containment hydrogen removal system for a nuclear power plant

International Nuclear Information System (INIS)

Callaghan, V.M.; Flynn, E.P.; Pokora, B.M.

1984-01-01

A hydrogen removal system (10) separates hydrogen from the containment atmosphere of a nuclear power plant using a hydrogen permeable membrane separator (30). Water vapor is removed by condenser (14) from a gas stream withdrawn from the containment atmosphere. The gas stream is then compressed by compressor (24) and cooled (28,34) to the operating temperature of the hydrogen permeable membrane separator (30). The separator (30) separates the gas stream into a first stream, rich in hydrogen permeate, and a second stream that is hydrogen depleted. The separated hydrogen is passed through a charcoal adsorber (48) to adsorb radioactive particles that have passed through the hydrogen permeable membrane (44). The hydrogen is then flared in gas burner (52) with atmospheric air and the combustion products vented to the plant vent. The hydrogen depleted stream is returned to containment through a regenerative heat exchanger (28) and expander (60). Energy is extracted from the expander (60) to drive the compressor (24) thereby reducing the energy input necessary to drive the compressor (24) and thus reducing the hydrogen removal system (10) power requirements

Reliability assessment on decay heat removal system of a fast reactor

International Nuclear Information System (INIS)

Hioki, Kazumasa

1991-01-01

The reliability of a decay heat removal system (DHRS) is influenced by the success criteria, the components which constitute the system, the support systems configuration, and the mission time. Assessments were performed to investigate quantitatively the effects of these items. Failure probabilities of DHRS under forced or natural circulation modes were calculated and then components and systems of large importance for each mode were identified. (author)

Nuclear reactor with makeup water assist from residual heat removal system

International Nuclear Information System (INIS)

Schulz, T.L.; Corletti, M.M.

1994-01-01

A pressurized water nuclear reactor uses its residual heat removal system to make up water in the reactor coolant circuit by pumping water from an in-containment refueling water storage tank during staged depressurization of the coolant circuit, the final stage including passive emergency cooling by gravity feed from the refueling water storage tank to the coolant circuit and to flood the containment building. When depressurization commences due to inadvertence or a manageable leak, the residual heat removal system is activated manually and avoids the final stage of depressurization with its flooding of the containment when such action is not necessary, but does not prevent the final stage when it is necessary. A high pressure makeup water storage tank coupled to the reactor coolant circuit holds makeup coolant at the operational pressure of the reactor. The staged depressurization system vents the coolant circuit to the containment, thus reducing the supply of makeup coolant. The level of makeup coolant can be sensed to trigger opening of successive depressurization conduits. The residual heat removal system can also be coupled in a loop with the refueling water supply tanks for cooling the tank. (Author)

Debris Removal Project K West Canister Cleaning System Performance Specification

International Nuclear Information System (INIS)

FARWICK, C.C.

1999-01-01

Approximately 2,300 metric tons Spent Nuclear Fuel (SNF) are currently stored within two water filled pools, the 105 K East (KE) fuel storage basin and the 105 K West (KW) fuel storage basin, at the U.S. Department of Energy, Richland Operations Office (RL). The SNF Project is responsible for operation of the K Basins and for the materials within them. A subproject to the SNF Project is the Debris Removal Subproject, which is responsible for removal of empty canisters and lids from the basins. Design criteria for a Canister Cleaning System to be installed in the KW Basin. This documents the requirements for design and installation of the system

BOA: Asbestos pipe insulation removal robot system. Phase 1

Energy Technology Data Exchange (ETDEWEB)

Schempf, H.; Bares, J.E.

1995-02-01

The project described in this report targets the development of a mechanized system for safe, cost-efficient and automated abatement of asbestos containing materials used as pipe insulation. Based on several key design criteria and site visits, a proof-of-concept prototype robot system, dubbed BOA, was designed and built, which automatically strips the lagging and insulation from the pipes, and encapsulates them under complete vacuum operation. The system can operate on straight runs of piping in horizontal or vertical orientations. Currently we are limited to four-inch diameter piping without obstacles as well as a somewhat laborious emplacement and removal procedure -- restrictions to be alleviated through continued development. BOA removed asbestos at a rate of 4-5 ft./h compared to 3 ft./h for manual removal of asbestos with a 3-person crew. The containment and vacuum system on BOA was able to achieve the regulatory requirement for airborne fiber emissions of 0.01 fibers/ccm/ 8-hr. shift. This program consists of two phases. The first phase was completed and a demonstration was given to a review panel, consisting of DOE headquarters and site representatives as well as commercial abatement industry representatives. Based on the technical and programmatic recommendations drafted, presented and discussed during the review meeting, a new plan for the Phase II effort of this project was developed. Phase 11 will consist of a 26-month effort, with an up-front 4-month site-, market-, cost/benefit and regulatory study before the next BOA robot (14 months) is built, and then deployed and demonstrated (3 months) at a DOE site (such as Fernald or Oak Ridge) by the beginning of FY`97.

Removal performance of toluene, p-xylene and ethylene using a plasma-pretreated biotrickling system

Energy Technology Data Exchange (ETDEWEB)

Kim, H.J.; Han, B.; Kim, S.J.; Kim, Y.J. [Korea Inst. of Machinery and Materials (Korea, Republic of)

2010-07-01

The use of biological systems for removing volatile organic compounds (VOCs) from gaseous emissions was discussed. The systems rely on microorganism activity and do not produce any secondary pollution. Recently, the integration of biofiltration and UV photooxidation has been performed to remove VOCs in air. The systems using both UV photooxidation and biofiltration removed recalcitrant and VOCs more effectively than a stand-alone process using only biofiltration, because the UV pre-treatment not only removes the gases, but also changes them to easily biodegradable and water soluble byproducts such as acids and aldehydes. The biotrickling filter in this study was exposed to toluene gas only for over one month to cultivate specific microorganisms. The non-thermal plasma was a dielectric barrier discharge (DBD) plasma. The performance for removing toluene, p-xylene, and ethylene by the biotrickling filter, the plasma reactor and the plasma-pretreated bio-trickling system was investigated at a variety of flow rates and inlet concentrations of the test gases. The experimental results showed that the removal efficiencies of the integrated system of non-thermal plasma and biotrickling filter for p-xylene and ethylene were enhanced by 28.0 and 29.7 percent respectively, and increased by only 5.3 percent for toluene, as compared to those of the stand-alone biotrickling filtration. It was concluded that the plasma-pretreated biofiltration system could enhance the performance of the biotrickling filter for removing VOC gases, particularly for reducing low biodegradable pollutants with high loading which are chemically different from the cultivated gases. 12 refs., 7 figs.

Experimental and analytical studies of a passive shutdown heat removal system for advanced LMRs

International Nuclear Information System (INIS)

Heineman, J.; Kraimer, M.; Lottes, P.; Pedersen, D.; Stewart, R.; Tessier, J.

1988-01-01

A facility designed and constructed to demonstrate the viability of natural convection passive heat removal systems as a key feature of innovative LMR Shutdown Heat Removal (SHR) systems is in operation at Argonne National Laboratory (ANL). This Natural Convection Shutdown Heat Removal Test Facility (NSTF) is being used to investigate the heat transfer performance of the GE/PRISM and the RI/SAFR passive designs. This paper presents a description of the NSTF, the pretest analysis of the Radiant Reactor Vessel Auxiliary Cooling System (RVACS) in support of the GE/PRISM IFR concept, and experiment results for the RVACS simulation. Preliminary results show excellent agreement with predicted system performance

Experimental and analytical studies of a passive shutdown heat removal system for advanced LMRs

Energy Technology Data Exchange (ETDEWEB)

Heineman, J.; Kraimer, M.; Lottes, P.; Pedersen, D.; Stewart, R.; Tessier, J.

1988-01-01

A facility designed and constructed to demonstrate the viability of natural convection passive heat removal systems as a key feature of innovative LMR Shutdown Heat Removal (SHR) systems is in operation at Argonne National Laboratory (ANL). This Natural Convection Shutdown Heat Removal Test Facility (NSTF) is being used to investigate the heat transfer performance of the GE/PRISM and the RI/SAFR passive designs. This paper presents a description of the NSTF, the pretest analysis of the Radiant Reactor Vessel Auxiliary Cooling System (RVACS) in support of the GE/PRISM IFR concept, and experiment results for the RVACS simulation. Preliminary results show excellent agreement with predicted system performance.

TMI defueling project fuel debris removal system

International Nuclear Information System (INIS)

Burdge, B.

1992-01-01

The three mile Island Unit 2 (TMI-2) pressurized water reactor loss-of-coolant accident on March 28, 1979, presented the nuclear community with many challenging remediation problems; most importantly, the removal of the fission products within the reactor containment vessel. To meet this removal problem, an air-lift system (ALS) can be used to employ compressed air to produce the motive force for transporting debris. Debris is separated from the transport stream by gravity separation. The entire method does not rely on any moving parts. Full-scale testing of the ALS at the Idaho National Engineering Laboratory (INEL) has demonstrated the capability of transporting fuel debris from beneath the LCSA into a standard fuel debris bucket at a minimum rate of 230 kg/min

High-efficiency SO{sub 2} removal in utility FGD systems

Energy Technology Data Exchange (ETDEWEB)

Phillips, J.L.; Gray, S.; Dekraker, D. [Radian Corporation, Austin, TX (United States)] [and others

1995-11-01

The U.S. Department of Energy (DOE) and the Electric Power Research Institute (EPRI) have contracted with Radian Corporation to conduct full-scale testing, process modeling, and economic evaluations of six existing utility flue gas desulfurization (FGD) systems. The project objective is to evaluate low capital cost upgrades for achieving up to 98% sulfur dioxide (SO{sub 2}) removal efficiency in a variety of FGD system types. The systems include dual-loop, packed absorbers at Tampa Electric Company`s Big Bend Station; cocurrent, packed absorbers at Hoosier Energy`s Merom Station; dual-loop absorbers with perforated-plate trays at Southwestern Electric Power Company`s Pirkey Station; horizontal spray absorbers at PSI Energy`s Gibson Station; venturi scrubbers at Duquesne Light`s Elrama Station; and open stray absorbers at New york State Electric and Gas Corporations`s (NYSEG`s) Kintigh Station. All operate in an inhibited-oxidation mode except the system at Big Bend (forced oxidation), and all use limestone reagent except the Elrama system (Mg-lime). The program was conducted to demonstrate that upgrades such as performance additives and/or mechanical modifications can increase system SO{sub 2} removal at low cost. The cost effectiveness of each upgrade has been evaluated on the basis of test results and/or process model predictions for upgraded performance and utility-specific operating and maintenance costs. Results from this upgraded performance and utility-specific operating and maintenance costs. Results from this program may lead some utilities to use SO{sub 2} removal upgrades as an approach for compliance with phase 2 of Title IV of the Clean Air Act Amendments (CAAA) of 1990. This paper summarizes the results of testing, modeling, and economic evaluations that have been completed since July, 1994.

Development of a new decay heat removal system for a high temperature gas-cooled reactor

International Nuclear Information System (INIS)

Sim, Yoon Sub; Park, Rae Young; Kim, Seyun

2007-01-01

The heat removal capacity of a RCCS is one of the major parameters limiting the capacity of a HTGR based on a passive safety system. To improve the plant economy of a HTGR, the decay heat removal capacity needs to be improved. For this, a new analysis system of an algebraic method for the performance of various RCCS designs was set up and the heat transfer characteristics and performance of the designs were analyzed. Based on the analysis results, a new passive decay heat removal system with a substantially improved performance, LFDRS was developed. With the new system, one can have an expectation that the heat removal capacity of a HTGR could be doubled

Pentek metal coating removal system: Baseline report; Greenbook (chapter)

International Nuclear Information System (INIS)

1997-01-01

The Pentek coating removal technology was tested and is being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU's evaluation of efficiency and cost, this report covers evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The Pentek coating removal system consisted of the ROTO-PEEN Scaler, CORNER-CUTTER reg-sign, and VAC-PAC reg-sign. They are designed to remove coatings from steel, concrete, brick, and wood. The Scaler uses 3M Roto Peen tungsten carbide cutters while the CORNER-CUTTER reg-sign uses solid needles for descaling activities. These hand tools are used with the VAC-PAC reg-sign vacuum system to capture dust and debris as removal of the coating takes place. The safety and health evaluation during the testing demonstration focused on two main areas of exposure: dust and noise. Dust exposure minimal, but noise exposure was significant. Further testing for each exposure is recommended because of the environment where the testing demonstration took place. It is feasible that the dust and noise levels will be higher in an enclosed operating environment of different construction. In addition, other areas of concern found were arm-hand vibration, whole-body, ergonomics, heat stress, tripping hazards, electrical hazards, machine guarding, and lockout/tagout

Mathematical modeling based evaluation and simulation of boron removal in bioelectrochemical systems.

Science.gov (United States)

Ping, Qingyun; Abu-Reesh, Ibrahim M; He, Zhen

2016-11-01

Boron removal is an arising issue in desalination plants due to boron's toxicity. As an emerging treatment concept, bioelectrochemical systems (BES) can achieve potentially cost-effective boron removal by taking advantage of cathodic-produced alkali. Prior studies have demonstrated successful removal of boron in microbial desalination cells (MDCs) and microbial fuel cells (MFCs), both of which are representative BES. Herein, mathematical models were developed to further evaluate boron removal by different BES and understand the key operating factors. The models delivered very good prediction of the boron concentration in the MDC integrated with Donnan Dialysis (DD) system with the lowest relative root-mean-square error (RMSE) of 0.00%; the predication of the MFC performance generated the highest RMSE of 18.55%. The model results of salt concentration, solution pH, and current generation were well fitted with experimental data for RMSE values mostly below 10%. The long term simulation of the MDC-DD system suggests that the accumulation of salt in the catholyte/stripping solution could have a positive impact on the removal of boron due to osmosis-driven convection. The current generation in the MDC may have little influence on the boron removal, while in the MFC the current-driven electromigration can contribute up to 40% of boron removal. Osmosis-induced convection transport of boron could be the major driving force for boron removal to a low level 22.2 in order to avoid boron accumulation in the anolyte effluent. Copyright © 2016 Elsevier B.V. All rights reserved.

Application of two-stage biofilter system for the removal of odorous compounds.

Science.gov (United States)

Jeong, Gwi-Taek; Park, Don-Hee; Lee, Gwang-Yeon; Cha, Jin-Myeong

2006-01-01

Biofiltration is a biological process which is considered to be one of the more successful examples of biotechnological applications to environmental engineering, and is most commonly used in the removal of odoriferous compounds. In this study, we have attempted to assess the efficiency with which both single and complex odoriferous compounds could be removed, using one- or two-stage biofiltration systems. The tested single odor gases, limonene, alpha-pinene, and iso-butyl alcohol, were separately evaluated in the biofilters. Both limonene and alpha-pinene were removed by 90% or more EC (elimination capacity), 364 g/m3/h and 321 g/m3/h, respectively, at an input concentration of 50 ppm and a retention time of 30 s. The iso-butyl alcohol was maintained with an effective removal yield of more than 90% (EC 375 g/m3/h) at an input concentration of 100 ppm. The complex gas removal scheme was applied with a 200 ppm inlet concentration of ethanol, 70 ppm of acetaldehyde, and 70 ppm of toluene with residence time of 45 s in a one- or two-stage biofiltration system. The removal yield of toluene was determined to be lower than that of the other gases in the one-stage biofilter. Otherwise, the complex gases were sufficiently eliminated by the two-stage biofiltration system.

A passive decay-heat removal system for an ABWR based on air cooling

Energy Technology Data Exchange (ETDEWEB)

Mochizuki, Hiroyasu, E-mail: mochizki@u-fukui.ac.jp [Research Institute of Nuclear Engineering, University of Fukui, 1-2-4 Kanawa-cho, Tsuruga, Fukui 914-0055 (Japan); Yano, Takahiro [School of Engineering, University of Fukui, 1-2-4 Kanawa-cho, Tsuruga, Fukui 914-0055 (Japan)

2017-01-15

Highlights: • A passive decay heat removal system for an ABWR is discussed using combined system of the reactor and an air cooler. • Effect of number of pass of the finned heat transfer tubes on heat removal is investigated. • The decay heat can be removed by air coolers with natural convection. • Two types of air cooler are evaluated, i.e., steam condensing and water cooling types. • Measures how to improve the heat removal rate and to make compact air cooler are discussed. - Abstract: This paper describes the capability of an air cooling system (ACS) operated under natural convection conditions to remove decay heat from the core of an Advanced Boiling Water Reactor (ABWR). The motivation of the present research is the Fukushima Severe Accident (SA). The plant suffered damages due to the tsunami and entered a state of Station Blackout (SBO) during which seawater cooling was not available. To prevent this kind of situation, we proposed a passive decay heat removal system (DHRS) in the previous study. The plant behavior during the SBO was calculated using the system code NETFLOW++ assuming an ABWR with the ACS. However, decay heat removal under an air natural convection was difficult. In the present study, a countermeasure to increase heat removal rate is proposed and plant transients with the ACS are calculated under natural convection conditions. The key issue is decreasing pressure drop over the tube banks in order to increase air flow rate. The results of the calculations indicate that the decay heat can be removed by the air natural convection after safety relief valves are actuated many times during a day. Duct height and heat transfer tube arrangement of the AC are discussed in order to design a compact and efficient AC for the natural convection mode. As a result, a 4-pass heat transfer tubes with 2-row staggered arrangement is the candidate of the AC for the DHRS under the air natural convection conditions. The heat removal rate is re-evaluated as

West Valley waste removal system study

International Nuclear Information System (INIS)

Janicek, G.P.

1981-04-01

This study addresses the specific task of removing high-level wastes from underground tanks at Western New York Nuclear Center and delivering them to an onsite waste solidification plant. It begins with a review of the design and construction features of the waste storage tanks pertinent to the waste removal task with particular emphasis on the unique and complex tank internals which severely complicate the task of removal. It follows with a review of tank cleaning techniques used and under study at both Hanford and Savannah River and previous studies proposing the use of these techniques at West Valley. It concludes from these reviews that existing techniques are not directly transferable to West Valley and that a new approach is required utilizing selected feature and attributes from existing methodology. The study also concludes, from an investigation of the constraints imposed by the processing facility, that waste removal will be intermittent, requiring batch transfer over the anticipated 3 years of processing operations. Based on these reviews and conclusions, the study proposes that the acid waste be processed first and that one of the 15,000-gallon acid tanks then be used for batch feeding the neutralized waste. The proposed system would employ commercially available pumping equipment to transfer the wastes from the batch tank to processing via existing process piping. A commercially available mixed-flow pump and eight turbine pumps would homogenize the neutralized waste in conjunction with eight custom-fabricated sluicers for periodic transfer to the batch tank

Applicability of Zeolite Based Systems for Ammonia Removal and Recovery From Wastewater.

Science.gov (United States)

Das, Pallabi; Prasad, Bably; Singh, Krishna Kant Kumar

2017-09-01

  Ammonia discharged in industrial effluents bears deleterious effects and necessitates remediation. Integrated systems devoted to recovery of ammonia in a useful form and remediation of the same addresses the challenges of waste management and its utilization. A comparative performance evaluation study was undertaken to access the suitability of different zeolite based systems (commercial zeolites and zeolites synthesized from fly ash) for removal of ammonia followed by its subsequent release. Four main parameters which were studied to evaluate the applicability of such systems for large scale usage are cost-effectiveness, ammonia removal efficiency, performance on regeneration, and ammonia release percentage. The results indicated that synthetic zeolites outperformed zeolites synthesized from fly ash, although the later proved to be more efficient in terms of total cost incurred. Process technology development in this direction will be a trade-of between cost and ammonia removal and release efficiencies.

Contaminant removal and hydraulic conductivity of laboratory rain garden systems for stormwater treatment.

Science.gov (United States)

Good, J F; O'Sullivan, A D; Wicke, D; Cochrane, T A

2012-01-01

In order to evaluate the influence of substrate composition on stormwater treatment and hydraulic effectiveness, mesocosm-scale (180 L, 0.17 m(2)) laboratory rain gardens were established. Saturated (constant head) hydraulic conductivity was determined before and after contaminant (Cu, Zn, Pb and nutrients) removal experiments on three rain garden systems with various proportions of organic topsoil. The system with only topsoil had the lowest saturated hydraulic conductivity (160-164 mm/h) and poorest metal removal efficiency (Cu ≤ 69.0% and Zn ≤ 71.4%). Systems with sand and a sand-topsoil mix demonstrated good metal removal (Cu up to 83.3%, Zn up to 94.5%, Pb up to 97.3%) with adequate hydraulic conductivity (sand: 800-805 mm/h, sand-topsoil: 290-302 mm/h). Total metal amounts in the effluent were pH was elevated (up to 7.38) provided by the calcareous sand in two of the systems, whereas the topsoil-only system lacked an alkaline source. Organic topsoil, a typical component in rain garden systems, influenced pH, resulting in poorer treatment due to higher dissolved metal fractions.

BOA II: pipe-asbestos insulation removal system

International Nuclear Information System (INIS)

Schempf, H.; Mutschler; Boehmke, S.; Chemel, B.; Piepgras, C.

1996-01-01

BOA system is a mobile pipe-external robotic crawler used to remotely strip and bag asbestos-containing lagging and insulation materials from various diameter pipes in (primarily) industrial installations. Steam and process lines within the DOE weapons complex warrant the use of a remote device due to high labor costs and high level of radioactive contamination, making manual removal costly and inefficient. Currently targeted facilities for demonstration and remediation are Fernald in Ohio and Oak Ridge in Tennessee

Removal of Shippingport Station primary system components and piping

International Nuclear Information System (INIS)

LaGuardia, T.S.; Lipsett, S.M.

1987-01-01

The dismantling workscope for the Shippingport Station Decommissioning Project was divided into subtasks to permit the work to be subcontracted to the maximum extent practicable. Major subtasks were identified and described by Activity specifications which could then be grouped into logical work packages to be put out for bid. Two of the largest dismantling work packages, removal of piping and components, were grouped together and designated as Activity Specifications 4 and 5. TLG Services, Inc. and Cleveland Wrecking Company formed a Joint Venture to perform this work during a two-year period at a cost of approximately $7 million. The major portions of this dismantling workscope are described. The primary system components within this workscope consist of the stainless steel reactor coolant piping, check valves, reactor coolant pumps, steam generators, and reactor purification demineralizers and coolers. The work performed, the heavy rigging preparations and procedures, the cutting tools used, component draining/capping techniques to prevent spills, contamination containment, airborne control techniques, and lessons learned during the removal of these primary system components are described. Summaries of crew size and composition, labor hours, duration hours and radiation exposure to workers are provided and discussed briefly. The successful completion of this work is evidence of the engineering, planning, equipment, materials and labor pool available to remove large, radioactively contaminated components safely. This experience will help decommissioning planners to prepare for the removal of reactor components in future decommissioning

Mathematical modeling based evaluation and simulation of boron removal in bioelectrochemical systems

Energy Technology Data Exchange (ETDEWEB)

Ping, Qingyun [Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States); Abu-Reesh, Ibrahim M. [Department of Chemical Engineering, College of Engineering, Qatar University, P.O. Box 2713, Doha (Qatar); He, Zhen, E-mail: zhenhe@vt.edu [Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States)

2016-11-01

Boron removal is an arising issue in desalination plants due to boron's toxicity. As an emerging treatment concept, bioelectrochemical systems (BES) can achieve potentially cost-effective boron removal by taking advantage of cathodic-produced alkali. Prior studies have demonstrated successful removal of boron in microbial desalination cells (MDCs) and microbial fuel cells (MFCs), both of which are representative BES. Herein, mathematical models were developed to further evaluate boron removal by different BES and understand the key operating factors. The models delivered very good prediction of the boron concentration in the MDC integrated with Donnan Dialysis (DD) system with the lowest relative root-mean-square error (RMSE) of 0.00%; the predication of the MFC performance generated the highest RMSE of 18.55%. The model results of salt concentration, solution pH, and current generation were well fitted with experimental data for RMSE values mostly below 10%. The long term simulation of the MDC-DD system suggests that the accumulation of salt in the catholyte/stripping solution could have a positive impact on the removal of boron due to osmosis-driven convection. The current generation in the MDC may have little influence on the boron removal, while in the MFC the current-driven electromigration can contribute up to 40% of boron removal. Osmosis-induced convection transport of boron could be the major driving force for boron removal to a low level < 2 mg L{sup −} {sup 1}. The ratio between the anolyte and the catholyte flow rates should be kept > 22.2 in order to avoid boron accumulation in the anolyte effluent. - Highlights: • Mathematical models are developed to understand boron removal in BES. • Boron removal can be driven by electromigration induced by current generation. • Diffusion induced by a salt concentration gradient also contributes to boron removal. • Osmosis and current driven convection transport play diverse roles in different BES.

Apparatus and method for removing solvent from carbon dioxide in resin recycling system

Science.gov (United States)

Bohnert, George W [Harrisonville, MO; Hand, Thomas E [Lee's Summit, MO; DeLaurentiis, Gary M [Jamestown, CA

2009-01-06

A two-step resin recycling system and method solvent that produces essentially contaminant-free synthetic resin material. The system and method includes one or more solvent wash vessels to expose resin particles to a solvent, the solvent contacting the resin particles in the one or more solvent wash vessels to substantially remove contaminants on the resin particles. A separator is provided to separate the solvent from the resin particles after removal from the one or more solvent wash vessels. The resin particles are next exposed to carbon dioxide in a closed loop carbon dioxide system. The closed loop system includes a carbon dioxide vessel where the carbon dioxide is exposed to the resin, substantially removing any residual solvent remaining on the resin particles after separation. A separation vessel is also provided to separate the solvent from the solvent laden carbon dioxide. Both the carbon dioxide and the solvent are reused after separation in the separation vessel.

Removal of fine particles in wet flue gas desulfurization system by heterogeneous condensation

Energy Technology Data Exchange (ETDEWEB)

Yang, L.J.; Bao, J.J.; Yan, J.P.; Liu, J.H.; Song, S.J.; Fan, F.X. [Southeast University, Nanjing (China). School of Energy & Environment

2010-01-01

A novel process to remove fine particles with high efficiency by heterogeneous condensation in a wet flue gas desulfurization (WFGD) system is presented. A supersaturated vapor phase, necessary for condensational growth of fine particles, was achieved in the SO{sub 2} absorption zone and at the top of the wet FGD scrubber by adding steam in the gas inlet and above the scrubbing liquid inlet of the scrubber, respectively. The condensational grown droplets were then removed by the scrubbing liquid and a high-efficiency demister. The results show that the effectiveness of the WFGD system for removal of fine particles is related to the SO{sub 2} absorbent employed. When using CaCO{sub 3} and NH{sub 3} {center_dot} H{sub 2}O to remove SO{sub 2} from flue gas, the fine particle removal efficiencies are lower than those for Na2CO{sub 3} and water, and the morphology and elemental composition of fine particles are changed. This effect can be attributed to the formation of aerosol particles in the limestone and ammonia-based FGD processes. The performance of the WFGD system for removal of fine particles can be significantly improved for both steam addition cases, for which the removal efficiency increases with increasing amount of added steam. A high liquid to gas ratio is beneficial for efficient removal of fine particles by heterogeneous condensation of water vapor.

Assessment of the cryogenic distillation system in Cernavoda tritium removal facility

International Nuclear Information System (INIS)

Pasca, Gheorghe; Draghia, Mirela; Porcariu, Florina; Ana, George

2010-01-01

Full text: This paper aims at presenting an assessment of the Cryogenic Distillation system (CD) in the Cernavoda Tritium Removal Facility (CTRF). The cryogenic distillation system is one of the key components of the CTRF which comprises other systems as: the liquid phase catalytic exchange system, designed to transfer tritium from heavy water to a deuterium stream to be fed into the CD system; the atmosphere detritiation system; the tritium recovery system; the tritium/hydrogen monitoring system; the central interlocking system; the tritium extraction and storage system. Thus, the need to build a tritium separation and recovery system results from economic opportunities offered both by heavy water reuse and tritium production, but, at the same time, it offers an alternative for the storage of tritiated heavy water as radioactive waste. (authors)

BOA: Pipe asbestos insulation removal robot system

International Nuclear Information System (INIS)

Schempf, H.; Bares, J.; Schnorr, W.

1995-01-01

The BOA system is a mobile pipe-external robotic crawler used to remotely strip and bag asbestos-containing lagging and insulation materials (ACLIM) from various diameter pipes in (primarily) industrial installations. Steam and process lines within the DOE weapons complex warrant the use of a remote device due to the high labor costs and high level of radioactive contamination, making manual removal extremely costly and highly inefficient. Currently targeted facilities for demonstration and remediation are Fernald in Ohio and Oak Ridge in Tennessee

BOA: Pipe-asbestos insulation removal robot system

Energy Technology Data Exchange (ETDEWEB)

Schempf, H.; Bares, J.; Schnorr, W. [Carnegie Mellon Univ., Pittsburgh, PA (United States)

1995-10-01

The BOA system is a mobile pipe-external robotic crawler used to remotely strip and bag asbestos-containing lagging and insulation materials (ACLIM) from various diameter pipes in (primarily) industrial installations. Steam and process lines within the DOE weapons complex warrant the use of a remote device due to the high labor costs and high level of radioactive contamination, making manual removal extremely costly and highly inefficient. Currently targeted facilities for demonstration and remediation are Fernald in Ohio and Oak Ridge in Tennessee.

BOA: Pipe-asbestos insulation removal robot system

International Nuclear Information System (INIS)

Schempf, H.; Bares, J.; Schnorr, W.

1995-01-01

The BOA system is a mobile pipe-external robotic crawler used to remotely strip and bag asbestos-containing lagging and insulation materials (ACLIM) from various diameter pipes in (primarily) industrial installations. Steam and process lines within the DOE weapons complex warrant the use of a remote device due to the high labor costs and high level of radioactive contamination, making manual removal extremely costly and highly inefficient. Currently targeted facilities for demonstration and remediation are Fernald in Ohio and Oak Ridge in Tennessee

Design of Passive Decay Heat Removal System using Mercury Thermosyphon for SFR

Energy Technology Data Exchange (ETDEWEB)

You, Byung Hyun; Jeong, Yong Hoon [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2013-10-15

In this study, thermosyphon application is suggested to accomplish the fully passive safety grade system and compactness of components via enhance the heat removal performance. A two-phase evaporating thermosyphon operates when the evaporator is heated, the working fluid start boiling, the vapor that is formed moves to the condenser, where it is condensed on the walls, giving up the heat of phase change to the cooling fluid. Gravity forces cause the condensate to condensed liquid flow to the evaporator again. These processes occur continuously, which causes transfer of heat from evaporator to condenser vice versa. After the thermal design and performance evaluation, the results were compared with the performance of conventional DRACS system. For the same amount of decay heat removal performance of PDRC system of KALIMER-600 mercury thermosyphon system can archive around 30∼50% of compactness. For the detailed design, improved analytical model and experimental data for the validation will be required to specify the new DHR system.

Satellite refrigerator compressors with the oil and moisture removal systems

International Nuclear Information System (INIS)

Satti, J.A.

1983-08-01

There are twenty-eight compressors installed around the Main Accelerator Ring in seven locations. Drawing 9140-ME-129720 shows the piping and the components schematic for four Mycom compressor skids per building with each having an independent oil and moisture removal system. The Mycom skids each consist of an oil injected screw compressor of 750 SCFM capacity with a 350 hp motor, oil pump, oil cooler, and oil separator. Helium gas returning from the heat exchanger train is compressed from 1 atm to 20 atm in the compressor. The compressed gas is then passed through the three coalescer de-mister where oil mist is separated from the helium gas. The helium gas then flows through the charcoal adsorber and molecular sieve where any residual oil vapor and water vapor are removed. The final stage of purification is the final filter which removes any remaining particulates from the compressed helium gas. The end product of this system is compressed and purified helium gas ready to be cooled down to cryogenic temperatures

Nitrogen removal and nitrate leaching for two perennial, sod-based forage systems receiving dairy effluent.

Science.gov (United States)

Woodard, Kenneth R; French, Edwin C; Sweat, Lewin A; Graetz, Donald A; Sollenberger, Lynn E; Macoon, Bisoondat; Portier, Kenneth M; Rymph, Stuart J; Wade, Brett L; Prine, Gordon M; Van Horn, Harold H

2003-01-01

In northern Florida, year-round forage systems are used in dairy effluent sprayfields to reduce nitrate leaching. Our purpose was to quantify forage N removal and monitor nitrate N (NO3(-)-N) concentration below the rooting zone for two perennial, sod-based, triple-cropping systems over four 12-mo cycles (1996-2000). The soil is an excessively drained Kershaw sand (thermic, uncoated Typic Quartzip-samment). Effluent N rates were 500, 690, and 910 kg ha(-1) per cycle. Differences in N removal between a corn (Zea mays L.)-bermudagrass (Cynodon spp.)-rye (Secale cereale L.) system (CBR) and corn-perennial peanut (Arachis glabrata Benth.)-rye system (CPR) were primarily related to the performance of the perennial forages. Nitrogen removal of corn (125-170 kg ha(-1)) and rye (62-90 kg ha(-1)) was relatively stable between systems and among cycles. The greatest N removal was measured for CBR in the first cycle (408 kg ha(-1)), with the bermudagrass removing an average of 191 kg N ha(-1). In later cycles, N removal for bermudagrass declined because dry matter (DM) yield declined. Yield and N removal of perennial peanut increased over the four cycles. Nitrate N concentrations below the rooting zone were lower for CBR than CPR in the first two cycles, but differences were inconsistent in the latter two. The CBR system maintained low NO3(-)-N leaching in the first cycle when the bermudagrass was the most productive; however, it was not a sustainable system for long-term prevention of NO3(-)-N leaching due to declining bermudagrass yield in subsequent cycles. For CPR, effluent N rates > or = 500 kg ha(-1) yr(-1) have the potential to negatively affect ground water quality.

Natural Organic Matter Removal and Fouling in a Low Pressure Hybrid Membrane Systems

Directory of Open Access Journals (Sweden)

Vedat Uyak

2014-01-01

Full Text Available The objective of this study was to investigate powdered activated carbon (PAC contribution to natural organic matter (NOM removal by a submerged MF and UF hybrid systems. It was found that filtration of surface waters by a bare MF and UF membranes removed negligible TOC; by contrast, significant amounts of TOC were removed when daily added PAC particles were predeposited on the membrane surfaces. These results support the assumption that the membranes surface properties and PAC layer structure might have considerably influential factor on NOM removal. Moreover, it was concluded that the dominant removal mechanism of hybrid membrane system is adsorption of NOM within PAC layer rather than size exclusion of NOM by both of membrane pores. Transmembrane pressure (TMP increases with PAC membrane systems support the view that PAC adsorption pretreatment will not prevent the development of membrane pressure; on the contrary, PAC particles themselves caused membrane fouling by blocking the entrance of pores of MF and UF membranes. Although all three source waters have similar HPI content, it appears that the PAC interaction with the entrance of membrane pores was responsible for offsetting the NOM fractional effects on membrane fouling for these source waters.

Results from evaporation tests to support the MWTF heat removal system design

International Nuclear Information System (INIS)

Crea, B.A.

1994-01-01

An experimental tests program was conducted to measure the evaporative heat removal from the surface of a tank of simulated waste. The results contained in this report constitute definition design data for the latest heat removal function of the MWTF primary ventilation system

Oxygen Limited Bioreactors System For Nitrogen Removal Using Immobilized Mix Culture

Science.gov (United States)

Pathak, B. K.; Sumino, T.; Saiki, Y.; Kazama, F.

2005-12-01

Recently nutrients concentrations especially nitrogen in natural water is alarming in the world wide. Most of the effort is being done on the removal of high concentration of nitrogen especially from the wastewater treatment plants. The removal efficiency is targeted in all considering the effluent discharge standard set by the national environment agency. In many cases, it does not meet the required standard and receiving water is being polluted. Eutrophication in natural water bodies has been reported even if the nitrogen concentration is low and self purification of natural systems itself is not sufficient to remove the nitrogen due to complex phenomenon. In order to recover the pristine water environment, it is very essential to explore bioreactor systems for natural water systems using immobilized mix culture. Microorganism were entrapped in Polyethylene glycol (PEG) prepolymer gel and cut into 3mm cubic immobilized pellets. Four laboratory scale micro bio-reactors having 0.1 L volumes were packed with immobilized pellets with 50% compact ratio. RUN1, RUN2, RUN3 and RUN4 were packed with immobilized pellets from reservoirs sediments, activated sludge (AS), mixed of AS, AG and biodegradable plastic and anaerobic granules (AG) respectively. Water from Shiokawa Reservoirs was feed to all reactors with supplemental ammonia and nitrite nitrogen as specified in the results and discussions. The reactors were operated dark incubated room in continuous flow mode with hydraulic retention time of 12 hours under oxygen limiting condition. Ammonium, nitrate nitrite nitrogen and total organic carbon (TOC) concentrations were measured as described in APWA and AWWA (1998). Laboratory scale four bioreactors containing different combination of immobilized cell were monitored for 218 days. Influent NH4+-N and NO2--N concentration were 2.27±0.43 and 2.05±0.41 mg/l respectively. Average dissolved oxygen concentration and pH in the reactors were 0.40-2.5 mg/l and pH 6

Technology for meat-grinding systems to improve removal of hard particles from ground meat.

Science.gov (United States)

Zhao, Y; Sebranek, J G

1997-03-01

With increased consumption of ground meat, especially ground beef, quality issues for these products have become more important to industry and consumers alike. Ground meats are usually obtained from relatively low-value cuts and trimmings, and may on occasion contain undesirable hard particles. Hard particles in coarse-ground meat products may include bone chips or fragments, cartilage and dense connective tissue; all of which are considered undesirable defects and which can be reduced by utilizing hard-particle removal systems during grinding operations. This review discusses the principles of hard-particle separation from ground meat, the factors which influence performance of particle separation and some commercially available particle removal systems. Product and processing parameters such as initial bone and connective tissue content, fat content, temperature, pre-grinding size and grinder knife design are considered important for removing hard particles effectively. Pressure gradient on the grinder knife/plate interface was found to play a significant role in particle separation from soft (fat and lean) tissue. Various commercial systems, which are classified as central removal and periphery removal systems, are also discussed. Finally, the authors suggest some processing considerations for meat grinding to help achieve the best quality ground meat for consumers' satisfaction.

BOA: Asbestos pipe-insulation removal robot system, Phase 2. Topical report, January--June 1995

Energy Technology Data Exchange (ETDEWEB)

Schempf, H.; Bares, J.E.

1995-06-01

This report explored the regulatory impact and cost-benefit of a robotic thermal asbestos pipe-insulation removal system over the current manual abatement work practice. The authors are currently in the second phase of a two-phase program to develop a robotic asbestos abatement system, comprised of a ground-based support system (including vacuum, fluid delivery, computing/electronics/power, and other subsystems) and several on-pipe removal units, each sized to handle pipes within a given diameter range. The intent of this study was to (i) aid in developing design and operational criteria for the overall system to maximize cost-efficiency, and (ii) to determine the commercial potential of a robotic pipe-insulation abatement system.

System Study: Residual Heat Removal 1998-2014

Energy Technology Data Exchange (ETDEWEB)

Schroeder, John Alton [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-12-01

This report presents an unreliability evaluation of the residual heat removal (RHR) system in two modes of operation (low-pressure injection in response to a large loss-of-coolant accident and post-trip shutdown-cooling) at 104 U.S. commercial nuclear power plants. Demand, run hours, and failure data from fiscal year 1998 through 2014 for selected components were obtained from the Institute of Nuclear Power Operations (INPO) Consolidated Events Database (ICES). The unreliability results are trended for the most recent 10 year period, while yearly estimates for system unreliability are provided for the entire active period. No statistically significant increasing trends were identified in the RHR results. A highly statistically significant decreasing trend was observed for the RHR injection mode start-only unreliability. Statistically significant decreasing trends were observed for RHR shutdown cooling mode start-only unreliability and RHR shutdown cooling model 24-hour unreliability.

Integrated nitrogen removal biofilter system with ceramic membrane for advanced post-treatment of municipal wastewater.

Science.gov (United States)

Son, Dong-Jin; Yun, Chan-Young; Kim, Woo-Yeol; Zhang, Xing-Ya; Kim, Dae-Gun; Chang, Duk; Sunwoo, Young; Hong, Ki-Ho

2016-12-01

The pre-denitrification biofilm process for nitrogen removal was combined with ceramic membrane with pore sizes of 0.05-0.1 µm as a system for advanced post-treatment of municipal wastewater. The system was operated under an empty bed hydraulic retention time of 7.8 h, recirculation ratio of 3, and transmembrane pressure of 0.47 bar. The system showed average removals of organics, total nitrogen, and solids as high as 93%, 80%, and 100%, respectively. Rapid nitrification could be achieved and denitrification was performed in the anoxic filter without external carbon supplements. The residual particulate organics and nitrogen in effluent from biofilm process could be also removed successfully through membrane filtration and the removal of total coliform was noticeably improved after membrane filtration. Thus, a system composed of the pre-denitrification biofilm process with ceramic membrane would be a compact and flexible option for advanced post-treatment of municipal wastewater.

Novel flow-through bioremediation system for removing nitrate from nursery discharge water.

Science.gov (United States)

Chris Wilson, P; Albano, Joseph P

2013-11-30

Nitrate losses in surface runoff water from nursery production areas can be significant. This study evaluated the potential use of microbial-based (denitrification), flow-through bioreactors for their nitrate-remediation ability. Duplicate bioreactor systems were constructed at a local foliage plant nursery. Each bioreactor system consisted of four 242 L tanks with connections alternating between bottom and top. Each tank was filled with approximately 113 L of Kaldness media to provide surface area for attachment of native microflora. Molasses was supplied as a carbon source for denitrification and water flow rates through the systems ranged from 5 to 18 L min(-1) during tests. Automatic water samplers were used to collect composite samples every 15 min from both the inflow and the exit flow water. Results indicate consistent removal of 80-100% of the nitrate flowing into the systems. Accumulation of ammoniacal and nitrite nitrogen did not occur, indicating that the nitrate-nitrogen was removed from the water, and not simply transformed into another water-soluble species. Occasions where removal rates were less than 80% were usually traced to faulty delivery of the carbon source. Results indicate that modular microbial-based bioremediation systems may be a useful tool for helping water managers meet stringent nitrogen water quality regulations, especially at nurseries with limited space for expansion of water retention facilities. Copyright © 2013 Elsevier Ltd. All rights reserved.

Arsenic removal from water employing a combined system: photooxidation and adsorption.

Science.gov (United States)

Lescano, Maia; Zalazar, Cristina; Brandi, Rodolfo

2015-03-01

A combined system employing photochemical oxidation (UV/H2O2) and adsorption for arsenic removal from water was designed and evaluated. In this work, a bench-scale photochemical annular reactor was developed being connected alternately to a pair of adsorption columns filled with titanium dioxide (TiO2) and granular ferric hydroxide (GFH). The experiences were performed by varying the relation of As concentration (As (III)/As (V) weight ratio) at constant hydrogen peroxide concentration and incident radiation. Experimental oxidation results were compared with theoretical predictions using an intrinsic kinetic model previously obtained. In addition, the effectiveness of the process was evaluated using a groundwater sample. The mathematical model of the entire system was developed. It could be used as an effective tool for the design and prediction of the behaviour of these types of systems. The combined technology is efficient and promising for arsenic removal to small and medium scale.

Controlled biomass removal - the key parameter to achieve enhanced biological phosphorus removal in biofilm systems

DEFF Research Database (Denmark)

Morgenroth, E.

1999-01-01

the influence of the following processes on EBPR in biofilms was evaluated: (1) mass transfer limitation for oxygen (2) mass transfer limitation for organic substrate, (3) lack of controlled removal of biomass from the system. It was shown that mass transfer of soluble components (oxygen and organic substrate...

ETV REPORT: REMOVAL OF CHEMICAL CONTAMINANTS IN DRINKING WATER — ECOWATER SYSTEMS, INC. ERO-R450E WATER TREATMENT SYSTEM

Science.gov (United States)

The EcoWater Systems ERO-R450E POU drinking water treatment system was tested for removal of aldicarb, benzene, cadmium, carbofuran, cesium, chloroform, dichlorvos, dicrotophos, fenamiphos, mercury, mevinphos, oxamyl, strontium, and strychnine. The ERO-R450E employs a reverse os...

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.

Technical solutions for tritium removal from Cernavoda NPP heavy water systems

International Nuclear Information System (INIS)

Barariu, Gheorghe; Panait, Adrian

2002-01-01

In CANDU nuclear plants 2400 KCi/GW(e) - year tritium is generated. At a CANDU - 600 reactor similar to Cernavoda NPP Unit 1, 1500 KCi/year of tritium is generated 95% being in the D 2 O moderator, which can achieve a radioactivity level of 80 - 100 Ci/kg. Tritium in heavy water contributes with 30 - 50% to the doses received by operation personnel and with 20% to the radioactivity released to the environment. The extraction of tritium heavy water at CANDU reactors implies the following possibilities: - the radioactivity level reduction in the operation area; - the maintenance and repair cost reduction due to reduction of personnel protection measures and increased labor productivity; - the increase of NPP utilization factor by shutdown time reduction for maintenance and repair; - tritium concentration reduction from technological systems, ensuring thus the possibility of redesigning the systems in order to lower the cost of investment; - profitable use of extracted tritium. Technical measures provided by AECL project for CANDU 600 at Cernavoda make possible to satisfy the current standards concerning tritium concentration in the operation area atmosphere of 5 x 10 -6 Ci/m 3 . The regulations recommend that the radioactivity level should be maintained as low as possible in conformity with ALARA principles. Also, it is possible that norms will become more restrictive in the future, so the tritium removal technology is a good preventive measure which may become very necessary. The methods, which currently reached the industrial or pilot stages, are based on catalyzed chemical exchange, the heavy water electrolysis, and deuterium distillation. They are known as: VPCE - Vapour Phase Catalytic Exchange; LPCE - Liquid Phase Catalytic Exchange; DE - Direct Electrolysis; CD - Cryogenic Distillation. As transfer processes the catalyzed chemical exchange and heavy water electrolysis are used while concentration of tritium gas is done by cryogenic distillation. At present the

The Effect of HLRs on Nitrogen Removal by Using a Pilot-scale Aerated Steel Slag System

Directory of Open Access Journals (Sweden)

Hamdan R.

2017-01-01

Full Text Available Discharge from domestic wastewater treatment plant amongst the main sources of nitrogen pollution in the environment. However, to remove nitrogen conventionally in domestic wastewater require high cost and complex chemical treatment method. Vertical flow aerated rock filter emerged as one of attractive alternative wastewater treatment method due to simplicity and compactness of the system. However, the application is yet to be developed in warm climate countries in particular Malaysia. Therefore, this study was conducted to investigate the effect of hydraulic loading rate (HLR to the performance of a pilot-scale Vertical Flow Aerated Rock Filter (VFARF in removing nitrogen from domestic wastewater using pilot-scale VFARF systems with steel slag as the filter media. Furthermore, this study has been designed to focus on the effects of two HLRs; 2.72 and 1.04 m3/m3.day. Influent and effluent of the filter systems were monitored biweekly basis for 11 weeks and analyzed for selected parameters. Results from this study shows that the VFARF with HLR 1.04 m3/m3.day has performed better in terms of removal ammonium-nitrogen and TKN as the system able to remove 90.4 ± 6.9%, 86.2 ± 10.7%, whilst the VFARF with 2.72 m3/m3.day remove 87.4 ± 9.9%, 80 ± 11.7%, respectively. From the observation, it can be concluded that nitrogen removal does affect by HLR as the removal in lower HLR system was higher due to high DO level in the VFARF system with 1.04 m3/m3.day which range from 4.5 to 5.1 mg/L whilst the DO level was slightly lower in the VFARF system with 2.72 m3/m3.day in the range of 3.7 to 4.5 mg/L.

An in vitro study: Evaluation of intracanal calcium hydroxide removal with different file systems

Directory of Open Access Journals (Sweden)

Atul Jain

2017-01-01

Full Text Available Background: Calcium hydroxide (Ca(OH2 is the most commonly used intracanal material; it needs to be removed in entirety before obturation. Several techniques have been used for the same including use of various hand and rotary files. Aim: This study was carried out to compare the efficacy of Hand K files and single and multiple rotary file system in removal of Ca(OH2. Methodology: Distobuccal root of 45 maxillary molars were selected on the basis of specified inclusion and exclusion criteria. They were divided into three groups - Group 1 (H and K file, Group 2 (HERO Shaper, and Group 3 (One Shape. Biomechanical preparation (BMP was carried out as per the manufacturer's instructions; 2.5% sodium hypochlorite was used as the irrigant and 17% ethylenediaminetetraacetic acid as the penultimate irrigant. Ca(OH2powder was mixed with normal saline to obtain a paste; canals were filled with this paste using a Lentulo spiral and were sealed. After 7 days, Ca(OH2was removed, using the same file system as that used for BMP. Samples were sectioned longitudinally and evaluated under a stereomicroscope. Statistical Analysis: Statistical analysis of the obtained data was carried out using one-way analysis of variance test. Results: HERO Shaper displayed better removal of Ca(OH2than One Shape and Hand K file. Moreover, removal was better in the middle third of canal than apical third. Conclusion: Multiple rotary file system (HERO Shaper is more effective in removal of Ca(OH2than the single file system (One Shape

Capital and Operating Cost of Small Arsenic Removal System and their Most Frequent Maintenance Problems

Science.gov (United States)

This presentation will first summarize the capital and operating cost of treatment systems by type and size of the systems. The treatment systems include adsorptive media (AM) systems, iron removal (IR), coagulation/filtration (CF), ion exchange (IX) systems, and point-of-use rev...

Passive safety systems for decay heat removal of MRX

Energy Technology Data Exchange (ETDEWEB)

Ochiai, M; Iida, H; Hoshi, T [Japan Atomic Energy Research Inst., Ibaraki (Japan). Nuclear Ship System Lab.

1996-12-01

The MRX (marine Reactor X) is an advanced marine reactor, its design has been studied in Japan Atomic Energy Research Institute. It is characterized by four features, integral type PWR, in-vessel type control rod drive mechanisms, water-filled containment vessel and passive decay heat removal system. A water-filled containment vessel is of great advantage since it ensures compactness of a reactor plant by realizing compact radiation shielding. The containment vessel also yields passive safety of MRX in the event of a LOCA by passively maintaining core flooding without any emergency water injection. Natural circulation of water in the vessels (reactor and containment vessels) is one of key factors of passive decay heat removal systems of MRX, since decay heat is transferred from fuel rods to atmosphere by natural circulation of the primary water, water in the containment vessel and thermal medium in heat pipe system for the containment vessel water cooling in case of long terms cooling after a LOCA as well as after reactor scram. Thus, the ideal of water-filled containment vessel is considered to be very profitable and significant in safety and economical point of view. This idea is, however, not so familiar for a conventional nuclear system, so experimental and analytical efforts are carried out for evaluation of hydrothermal behaviours in the reactor pressure vessel and in the containment vessel in the event of a LOCA. The results show the effectiveness of the new design concept. Additional work will also be conducted to investigate the practical maintenance of instruments in the containment vessel. (author). 4 refs, 9 figs, 2 tabs.

Removal of heavy-metal ions from dilute waste streams using membrane-based hybrid systems

International Nuclear Information System (INIS)

Friesen, D.T.; Edlund, D.J.

1993-01-01

At Bend research, the authors have developed hybrid systems that couple a process that removes solvent (water) and a process that removes solute (metal ions) such that toxic heavy-metal ions can be efficiently and selectively removed to very low levels while simultaneously concentrating the heavy-metal ions in relatively pure form. Although this technology is broadly applicable, the authors are focusing on the development of a system to treat groundwater that is contaminated with heavy-metal ions. The process utilizes coupled transport and reverse osmosis to reduce chromium and uranium concentration down to parts-per-billion levels

The effect of four different irrigation systems in the removal of a root canal sealer.

Science.gov (United States)

Grischke, J; Müller-Heine, A; Hülsmann, M

2014-09-01

The aim of this study was to compare the efficiency of sonic, ultrasonic, and hydrodynamic devices in the removal of a root canal sealer from the surface and from simulated irregularities of root canals. Fifty-three root canals with two standardized grooves in the apical and coronal parts of longitudinally split roots were covered with AH Plus root canal sealer. Compared were the effects of (control) syringe irrigation, (1) CanalBrush, (2) passive ultrasonic irrigation, (3) EndoActivator, and (4) RinsEndo on the removal of the sealer. The specimens were divided into four groups (N = 12) and one control group (N = 5) via randomization. The amount of remaining sealer in the root canal irregularities was evaluated under a microscope using a 4-grade scoring system, whereas the remaining sealer on the root canal surface was evaluated with a 7-grade scoring system. Passive ultrasonic irrigation is more effective than the other tested irrigation systems or syringe irrigation in removing sealer from root canal walls (p irrigation shows a superior effect on sealer removal from the root canal surface during endodontic retreatment. Cleaning of lateral grooves seems not to be possible with one of the techniques investigated. Incomplete removal of root canal sealer during re-treatment may cause treatment failure. Passive Ultrasonic irrigation seems to be the most effective system to remove sealer from a root canal.

ENSURING SANITARY RELIABILITY OF TERRITORIES WHEN USING REMOVABLE SEWERAGE SYSTEM

Directory of Open Access Journals (Sweden)

Nikitina Irina Nikolaevna

2015-12-01

Full Text Available It was found out that in most cases the system of removable water disposal is arranged with violations, i.e. cesspools that collect runoffs are either not designed at all — waste water merge into an open trench (ditch, and then water is filtered into the ground, or are designed against the rules (instead of a cesspool the user presupposes a simple hole dug in the ground. The authors witnessed the cases of ingress of wastewater into open waters, near which holiday villages are situated. This fact raises the question on the necessity of solving these problems which will prevent pollution of soil and surface waters, as well as the surrounding areas by sewages to prevent the development of infections and to prevent environmental disaster on a local scale. If you have a small rate of water flow in a summer cottage, it is feasible to design a sump for removal of faecal discharge (human physiological discharge, which are the most dangerous. It is advisable to install in the ground sealed (cumulative capacity, and build headroom on the top in the form of a toilet cabin (detached structure. This will allow completely getting rid of contamination with sewage effluents. The volume of the tank must be calculated individually depending on the water consumption on the site. Periodically it is needed to call out a cesspoolage truck after filling the reservoir, which would be then emptied of faecal material. In the last 20 years in our country a promising trend in removable sanitation began to develop — bio toilets. They became popular in country houses, as well as for persons with disabilities A composting toilet is a portable container, which is very compact and can be installed in any location of a country house. A more costly option, but an environmentally sound and convenient one to use is the construction of local water disposal systems with the use of not only mechanical, but also biological treatment. The choice of a particular scheme of

Removal of nitrogen and phosphorus from dairy wastewater using constructed wetlands systems operating in batch

Directory of Open Access Journals (Sweden)

Ronaldo Rocha Bastos

2012-08-01

Full Text Available This work presents the results of a study conducted for a period of seven months on the effectiveness of constructed wetland systems for the treatment of dairy wastewater aiming at removing, nitrogen and phosphorus. Six experimental systems were assembled with a net volume of 115 L using HDPE tanks, with length/width ratio of 2:1. In three of the systems, gravel 0 was used as substrate, while gravel 0 and sand was used in the three others, in the percentage of 80% and 20%, respectively. The systems were operated in batch cycles of 48 hours, applying 7.5 L of influent per cycle. Four of the experimental units were cultivated, and two kept as controls. The selected species chosen were the macrophytes, Typha domingensis and Hedychium coronarium. The removal efficiency concerning nitrogen compounds showed to be quite promising with values ranging from 29.4 to 73.4%, while phosphorus removal from the beds was lower, reaching efficiencies between 18.61 and 34.3%, considered good values, since the removal of these substances is quite difficult through conventional treatment.

ROGER a potential orbital space debris removal system

Science.gov (United States)

Starke, Juergen; Bischof, Bernd; Foth, W.-O.; -J., J.; Günther

The previous activities in the field of On Orbit Servicing studied in the 1990's included in partic-ular the capability of vehicles in GEO to capture and support satellites (mainly communication satellites) to enable repair and continuation of operations, and finally the controlled transfer the target into a permanent graveyard orbit. The specific capture tools for these applications were mostly based on robotic systems to capture and fix the target under specific dynamic constraints (e.g. slowly tumbling target) without damage, and to allow the stabilization, re-orientation and potential repair of the target and subsequent release or transport to the final disposal orbit. Due to the drastically increasing number of debris particularly in the Low Earth Orbits (SSO) the active debris removal is now necessary to counteract to the predicted debris production cascade (Kessler Syndrome), which means the pollution of the total sphere in low earth orbit and not only the SSO area. In most of the debris congresses it was recommended to start removal with the still integrated systems as soon as possible. In the case of large debris objects, the soft capture system can be replaced by a simpler and robust system able to operate from a safe distance to the target and flexible enough to capture and hold different types of targets such as deactivated and/or defective satellites, upper stages and big fragments. These nominally non -cooperative targets might be partially destroyed by the capture process, but the production of additional debris shall be avoided. A major argument for the commercial applications is a multi-target mission potential, which is possible at GEO because the transfer propellant requirement to the disposal orbit and the return to the orbit of the next potential target is relative low (orbits with similar inclination and altitude). The proposed ROGER system is designed as a spacecraft with rendezvous capabilities including inspection in the vicinity of the

Performance of ALMR passive decay heat removal system

International Nuclear Information System (INIS)

Boardman, C.E.; Hunsbedt, A.

1991-01-01

The Advanced Liquid Metal Reactor (ALMR) concept has a totally passive safety-grade decay heat removal system referred to as the Reactor Vessel Auxiliary Cooling System (RVACS) that rejects heat from the small (471 MWt) modular reactor to the environmental air by natural convection heat transfer. The system has no active components, requires no operator action to initiate, and is inherently reliable. The RVACS can perform its function under off-normal or degraded operating conditions without significant loss in performance. Several such events are described and the RVACS thermal performance for each is given and compared to the normal operation performance. The basic RVACS performance as well as the performance during several off-normal events have been updated to reflect design changes for recycled fuel with minor actinides for end of equilibrium cycle conditions. The performance results for several other off-normal events involving various degrees of RVACS air flow passage blockages are presented. The results demonstrated that the RVACS is unusually tolerant to a wide range of postulated faults. (author)

A coupled system of half-nitritation and ANAMMOX for mature landfill leachate nitrogen removal.

Science.gov (United States)

Li, Yun; Li, Jun; Zhao, Baihang; Wang, Xiujie; Zhang, Yanzhuo; Wei, Jia; Bian, Wei

2017-09-01

A coupled system of membrane bioreactor-nitritation (MBR-nitritation) and up-flow anaerobic sludge blanket-anaerobic ammonium oxidation (UASB-ANAMMOX) was employed to treat mature landfill leachate containing high ammonia nitrogen and low C/N. MBR-nitritation was successfully realized for undiluted mature landfill leachate with initial concentrations of 900-1500 mg/L [Formula: see text] and 2000-4000 mg/L chemical oxygen demand. The effluent [Formula: see text] concentration and the [Formula: see text] accumulation efficiency were 889 mg/L and 97% at 125 d, respectively. Half-nitritation was quickly realized by adjustment of hydraulic retention time and dissolved oxygen (DO), and a low DO control strategy could allow long-term stable operation. The UASB-ANAMMOX system showed high effective nitrogen removal at a low concentration of mature landfill leachate. The nitrogen removal efficiency was inhibited at excessive influent substrate concentration and the nitrogen removal efficiency of the system decreased as the concentration of mature landfill leachate increased. The MBR-nitritation and UASB-ANAMMOX processes were coupled for mature landfill leachate treatment and together resulted in high effective nitrogen removal. The effluent average total nitrogen concentration and removal efficiency values were 176 mg/L and 83%, respectively. However, the average nitrogen removal load decreased from 2.16 to 0.77 g/(L d) at higher concentrations of mature landfill leachate.

Development of contaminated concrete removing system 'Clean cut method'

International Nuclear Information System (INIS)

Kinoshita, Takehiko; Tanaka, Tsutomu; Funakawa, Naoyoshi; Idemura, Hajime; Sakashita, Fumio; Tajitsu, Yoshiteru

1989-01-01

In the case of decommissioning nuclear facilities such as nuclear power stations, nuclear fuel facilities and RI handling facilities and carrying out reconstruction works, if there is radioactive contamination on the surfaces of concrete structures such as the floors and walls of the buildings for nuclear facilities, it must be removed. Since concrete is porous, contamination infiltrates into the inside of concrete, and the wiping of surfaces only or chemical decontamination cannot remove it, therefore in most cases, contaminated concrete must be removed. The removal of concrete surfaces has been carried out with chipping hammers, grinders and so on, but many problems arise due to it. In order to solve these problems, the mechanical cutting method was newly devised, and clean cut method (CCRS) was completed. The depth of cutting from concrete surface is set beforehand, and the part to be removed is accurately cut, at the same time, the concrete powder generated is collected nearly perfectly, and recovered into a drum. The outline of the method and the constitution of the system, the features of the clean cut method, the development of the technology for cutting concrete and the technology for recovering concrete powder, and the test of verifying decontamination are reported. (K.I.)

300 GPM Solids Removal System A True Replacement for Back Flushable Powdered Filter Systems - 13607

Energy Technology Data Exchange (ETDEWEB)

Ping, Mark R.; Lewis, Mark [EnergySolutions, Suite 100, Center Point II, 100 Center Point Circle, Columbia, SC 29210 (United States)

2013-07-01

The EnergySolutions Solids Removal System (SRS) utilizes stainless steel cross-flow ultra-filtration (XUF) technology which allows it to reliably remove suspended solids greater than one (1) micron from liquid radwaste streams. The SRS is designed as a pre-treatment step for solids separation prior to processing through other technologies such as Ion Exchange Resin (IER) and/or Reverse Osmosis (RO), etc. Utilizing this pre-treatment approach ensures successful production of reactor grade water while 1) decreasing the amount of radioactive water being discharged to the environment; and 2) decreasing the amount of radioactive waste that must ultimately be disposed of due to the elimination of spent powdered filter media. (authors)

300 GPM Solids Removal System A True Replacement for Back Flushable Powdered Filter Systems - 13607

International Nuclear Information System (INIS)

Ping, Mark R.; Lewis, Mark

2013-01-01

The EnergySolutions Solids Removal System (SRS) utilizes stainless steel cross-flow ultra-filtration (XUF) technology which allows it to reliably remove suspended solids greater than one (1) micron from liquid radwaste streams. The SRS is designed as a pre-treatment step for solids separation prior to processing through other technologies such as Ion Exchange Resin (IER) and/or Reverse Osmosis (RO), etc. Utilizing this pre-treatment approach ensures successful production of reactor grade water while 1) decreasing the amount of radioactive water being discharged to the environment; and 2) decreasing the amount of radioactive waste that must ultimately be disposed of due to the elimination of spent powdered filter media. (authors)

Comparisons Study of Phosphate Removal in Unaerated and Aerated High Calcium Steel Slag Filter System of Different pH Feed

Directory of Open Access Journals (Sweden)

Ahmad Siti Zu Nurain

2017-01-01

Full Text Available Excess phosphorus in water body will lead to eutrophication. This study investigated the phosphate removal efficiencies of unaerated and aerated filter systems using high composition of Calcium (Ca steel slag as the filter media at different pH values of the wastewater influents. Lab-scale filters were developed using 25 mg/L synthetic wastewater and weekly sampling was done to monitor the phosphate removal efficiencies together with the concentration of metals (Calcium (Ca and Magnesium (Mg. The results show that both unaerated and aerated systems have excellent phosphate removal efficiency at all acidic, neutral and alkaline pH feed, though unaerated systems removed slightly better compared to aerated systems; 76-98% and 69-97% respectively. The dominant phosphate removal mechanism for aerated systems was adsorption, meanwhilefor unaerated systems; both adsorption and precipitation for acidic and neutral pH, whileprecipitation was more dominant at basic pH. The performance of unaerated systems are slightly better compared to aerated systems, however, aerated systems are recommended to be applied when simultaneous removal of nutrients (phosphorus and nitrogen are concerned.

Enhanced Cr(VI) removal from groundwater by Fe0-H2O system with bio-amended iron corrosion

DEFF Research Database (Denmark)

Yin, Weizhao; Li, Yongtao; Wu, Jinhua

2017-01-01

Abstract A one-pot bio-iron system was established to investigate synergetic abiotic and biotic effects between iron and microorganisms on Cr(VI) removal. More diverse iron corrosion and reactive solids, such as green rusts, lepidocrocite and magnetite were found in the bio-iron system than...... transfer on the solid phase. The results also showed that the reduction of Cr(VI) by microorganisms was insignificant, indicating the adsorption/co-precipitation of Cr by iron oxides on iron surface was responsible for the overall Cr(VI) removal. Our study demonstrated that the bio-amended iron corrosion...... in the Fe0-H2O system, leading to 4.3 times higher Cr(VI) removal efficiency in the bio-iron system than in the Fe0-H2O system. The cycling experiment also showed that the Cr(VI) removal capacity of Fe0 in the bio-iron system was 12.4 times higher than that in the Fe0-H2O system. A 62 days of life...

Research on How to Remove Efficiently the Condensate Water of Sampling System

International Nuclear Information System (INIS)

Cho, SungHwan; Kim, MinSoo; Choi, HoYoung; In, WonHo

2015-01-01

Corrosion was caused in the measurement chamber inside the O 2 and H 2 analyzer, and thus measuring the concentration of O 2 and H 2 was not possible. It was confirmed that the cause of the occurrence of condensate water is due to the temperature difference caused during the process of the internal gas of the disposal and degasifier tank being brought into the analyzer. Thus, a heating system was installed inside and outside of the sampling panel for gas to remove generated condensate water in the analyzer and pipe. For the case where condensate water is not removed by the heating system, drain port is also installed in the sampling panel for gas to collect the condensate water of the sampling system. It was verified that there is a great volume of condensate water existing in the pipe line during the purging process after installing manufactured goods. The condensate water was fully removed by the installed heating cable and drain port. The heating cable was operated constantly at a temperature of 80 to 90 .deg. C, which allows the precise measurement of gas concentration and longer maintenance duration by blocking of the condensate water before being produced. To install instruments for measuring the gas, such as an O 2 and H 2 analyzer etc., consideration regarding whether there condensate water is present due to the temperature difference between the measuring system and analyzer is required

Research on How to Remove Efficiently the Condensate Water of Sampling System

Energy Technology Data Exchange (ETDEWEB)

Cho, SungHwan; Kim, MinSoo; Choi, HoYoung; In, WonHo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

Corrosion was caused in the measurement chamber inside the O{sub 2} and H{sub 2} analyzer, and thus measuring the concentration of O{sub 2} and H{sub 2} was not possible. It was confirmed that the cause of the occurrence of condensate water is due to the temperature difference caused during the process of the internal gas of the disposal and degasifier tank being brought into the analyzer. Thus, a heating system was installed inside and outside of the sampling panel for gas to remove generated condensate water in the analyzer and pipe. For the case where condensate water is not removed by the heating system, drain port is also installed in the sampling panel for gas to collect the condensate water of the sampling system. It was verified that there is a great volume of condensate water existing in the pipe line during the purging process after installing manufactured goods. The condensate water was fully removed by the installed heating cable and drain port. The heating cable was operated constantly at a temperature of 80 to 90 .deg. C, which allows the precise measurement of gas concentration and longer maintenance duration by blocking of the condensate water before being produced. To install instruments for measuring the gas, such as an O{sub 2} and H{sub 2} analyzer etc., consideration regarding whether there condensate water is present due to the temperature difference between the measuring system and analyzer is required.

Numerical investigation of passive heat removal system via steam generator in VVER 1200

International Nuclear Information System (INIS)

Dinh Anh Tuan; Duong Thanh Tung; Tran Chi Thanh; Nguyen Van Thai

2015-01-01

Passive heat removal system (PHRS) via Steam Generator is an important part in VVER design. In case of Design Basic Accidents such as blackout, failure of feed water supply to steam generator or coolant leakage with failure of emergency core cooling at high pressure. PHRS is designed to remove the residual heat from reactor core through steam generator to heat exchanger which is placed outside reactor vessel. In order to evaluate the passive system, a numerical investigation using a CFD code is performed. However, PHRS has complex geometry for using CFD simulation. Thus, RELAP5 is applied to provide the wall heat flux of tube in the heat exchanger tank. The natural convection in the heat exchanger tank is investigated in this report. Numerical results show temperature and velocity distribution in the heat exchanger tank are calculated with different wall heat flux corresponding to various transient conditions. The calculated results contribute to the capacity analysis of passive heat removal system and giving valuable information for safe operation of VVER 1200. (author)

Evaluation of Organic Matter Removal Efficiency and Microbial Enzyme Activity in Vertical-Flow Constructed Wetland Systems

Directory of Open Access Journals (Sweden)

Qiaoling Xu

2016-09-01

Full Text Available In this study, enzyme activities and their relationships to organics purification were investigated in three different vertical flow constructed wetlands, namely system A (planting Pennisetum sinese Roxb, system B (planting Pennisetum purpureum Schum., and system C (no plant. These three wetland systems were fed with simulation domestic sewage at an influent flow rate of 20 cm/day. The results showed that the final removal efficiency of Chemical Oxygen Demand (COD in these three systems was 87%, 85% and 63%, respectively. Planting Pennisetum sinese Roxb and Pennisetum purpureum Schum. could improve the amount of adsorption and interception for organic matter in the substrate, and the amount of interception of organic matter in planting the Pennisetum sinese Roxb system was higher than that in planting the Pennisetum purpureum Schum. system. The activities of enzymes (urease, phosphatase and cellulase in systems A and B were higher than those in system C, and these enzyme activities in the top layer (0–30 cm were significantly higher than in the other layers. The correlations between the activities of urease, phosphatase, cellulase and the COD removal rates were R = 0.815, 0.961 and 0.973, respectively. It suggests that using Pennisetum sinese Roxb and Pennisetum purpureum Schum. as wetland plants could promote organics removal, and the activities of urease, phosphatase and cellulase in those three systems were important indicators for COD purification from wastewater. In addition, 0–30 cm was the main function layer. This study could provide a theoretical basis for COD removal in the wetland system and supply new plant materials for selection.

Optimization of the Carbon Dioxide Removal Assembly (CDRA-4EU) in Support of the International Space System and Advanced Exploration Systems

Science.gov (United States)

Knox, James C.; Stanley, Christine M.

2015-01-01

The Life Support Systems Project (LSSP) under the Advanced Exploration Systems (AES) program builds upon the work performed under the AES Atmosphere Resource Recovery and Environmental Monitoring (ARREM) project focusing on the numerous technology development areas. The Carbon Dioxide (CO2) removal and associated air drying development efforts are focused on improving the current state-of-the-art system on the International Space Station (ISS) utilizing fixed beds of sorbent pellets by seeking more robust pelletized sorbents, evaluating structured sorbents, and examining alternate bed configurations to improve system efficiency and reliability. A component of the CO2 removal effort utilizes a virtual Carbon Dioxide Removal Assembly, revision 4 (CDRA-4) test bed to test a large number of potential operational configurations with independent variations in flow rate, cycle time, heater ramp rate, and set point. Initial ground testing will provide prerequisite source data and provide baseline data in support of the virtual CDRA. Once the configurations with the highest performance and lowest power requirements are determined by the virtual CDRA, the results will be confirmed by testing these configurations with the CDRA-4EU ground test hardware. This paper describes the initial ground testing of select configurations. The development of the virtual CDRA under the AES-LSS Project will be discussed in a companion paper.

Advanced Product Water Removal and Management (APWR) Fuel Cell System, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The proposed innovation is a passive, self-regulating, gravity-independent Advanced Product Water Removal (APWR) system for Polymer Electrolyte Membrane (PEM)...

Bacteriophage Technique for Assessing Viral Removal in Constructed Wetland and Detention Pond Systems

Directory of Open Access Journals (Sweden)

Z Yousefi, CM Davies, HJ Bavor

2004-10-01

Full Text Available Constructed wetland and detention pond as a treatment system was applied for stormwater management in two adjacent areas in western Sydney. F-specific RNA and somatic coliphages were used as a model for assessing two systems for removal of viral pollution, fate, behavior and survival of viruses in the sediment. Water samples were collected weekly in sterile containers and sediment samples were collected three times using a box dredge sampler via a boat at the inlet, middle and outlet areas of the systems. F-specific RNA coliphages were enumerated using the double layer plaque assay (ISO 1995 with Salmonella typhimurium WG49 as a host. Survival test continued 28 d for each sub-sample. Viral removal in constructed wetland was more effective than the detention pond system. Survival of somatic coliphages in the inlet and middle of the systems was similar. Slope of declining for outlet of two systems was very slow and completely stable in whole of test duration. Constructed wetland may offer an attractive alternative to stormwater management for reducing the load of disease-causing viruses to the receiving waters.

A removable optical sealing system for application to international safeguards

International Nuclear Information System (INIS)

Martin, R.E.

1985-06-01

A removable, optically verifiable sealing system for CANDU spent fuel storage facilities has been developed. The seal is based on the use of unique crystal patterns formed in a pure metal identity/integrity element and has been designed for easy installation and removal using simple tooling. Since the seal is optically verified, a wide range of commercial instruments, including those in use by the IAEA, can be used to verify it. Futhermore, optical verification allows the level of scrutiny to be matched with the degree of confidence required to be confident that spent fuel has not been diverted

Advanced Product Water Removal and Management (APWR) Fuel Cell System, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The proposed innovation is a passive, self-regulating, gravity-independent Advanced Product Water Removal and management (APWR) system for incorporation into Polymer...

Construction of an integrated enzyme system consisting azoreductase and glucose 1-dehydrogenase for dye removal.

Science.gov (United States)

Yang, Yuyi; Wei, Buqing; Zhao, Yuhua; Wang, Jun

2013-02-01

Azo dyes are toxic and carcinogenic and are often present in industrial effluents. In this research, azoreductase and glucose 1-dehydrogenase were coupled for both continuous generation of the cofactor NADH and azo dye removal. The results show that 85% maximum relative activity of azoreductase in an integrated enzyme system was obtained at the conditions: 1U azoreductase:10U glucose 1-dehydrogenase, 250mM glucose, 1.0mM NAD(+) and 150μM methyl red. Sensitivity analysis of the factors in the enzyme system affecting dye removal examined by an artificial neural network model shows that the relative importance of enzyme ratio between azoreductase and glucose 1-dehydrogenase was 22%, followed by dye concentration (27%), NAD(+) concentration (23%) and glucose concentration (22%), indicating none of the variables could be ignored in the enzyme system. Batch results show that the enzyme system has application potential for dye removal. Copyright © 2012 Elsevier Ltd. All rights reserved.

Asbestos removal and disposal information system: a user's guide

International Nuclear Information System (INIS)

Knight, P.S.; Eisenhower, B.M.

1982-10-01

Program ASBS01, written for the staff of the Department of Environmental Management (DEM) at Oak Ridge National Laboratory (ORNL), is an on-line management information system that provides file maintenance and information retrievability for demolition and/or renovation operations involving friable (capable of becoming an airborne health hazard) asbestos material at the Laboratory. System 1022 is the data base management system used. The screen processor SCOPE provides the DEM staff with system prompts for ease of use and data integrity. Data for the system comes from two UCN forms: (1) Notice of Intention to Demolish or Renovate Friable Asbestos Material (UCN-13385) and (2) Request for the Disposal of Asbestos or Material Containing Asbestos (UCN-13386). Examples of the forms are in Appendix A. Data is entered into the system as requests are submitted to DEM. Total amounts of friable asbestos removed in demolition and/or renovation operations can be generated by the program upon user request. These totals are submitted in a quarterly report to the Environmental Protection Branch of the US Department of Energy (DOE) on a continuing basis (see Appendix B). This report describes the operation of the computer program ASBS01 from data entry to generation of totals. Each data attribute of the master file ASBSTO.DMS is described in detail, and a sample session is given for user reference

Costs of Arsenic Removal Technologies for Small Water Systems: U.S. EPA Arsenic Removal Technology Demonstration Program

Science.gov (United States)

As part of the Arsenic Rule Implementation Research Program, between July 2003 and July 2011, the U.S. environmental Protection Agency (EPA) conducted 50 full-scale demonstration projects on treatment systems removing arsenic from drinking water in 26 states throughout the U.S. ...

Capital and Operating Costs of Small Arsenic Removal Adsorptive Media Systems

Science.gov (United States)

The U.S. Environmental Protection Agency (EPA) conducted 50 full-scale demonstration projects on treatment systems removing arsenic from drinking water in 26 states throughout the U.S. The projects were conducted to evaluate the performance, reliability, and cost of arsenic remo...

Passive Decay Heat Removal System Options for S-CO2 Cooled Micro Modular Reactor

International Nuclear Information System (INIS)

Moon, Jangsik; Jeong, Yong Hoon; Lee, Jeong Ik

2014-01-01

To achieve modularization of whole reactor system, Micro Modular Reactor (MMR) which has been being developed in KAIST took S-CO 2 Brayton power cycle. The S-CO 2 power cycle is suitable for SMR due to high cycle efficiency, simple layout, small turbine and small heat exchanger. These characteristics of S-CO 2 power cycle enable modular reactor system and make reduced system size. The reduced size and modular system motived MMR to have mobility by large trailer. Due to minimized on-site construction by modular system, MMR can be deployed in any electricity demand, even in isolated area. To achieve the objective, fully passive safety systems of MMR were designed to have high reliability when any offsite power is unavailable. In this research, the basic concept about MMR and Passive Decay Heat Removal (PDHR) system options for MMR are presented. LOCA, LOFA, LOHS and SBO are considered as DBAs of MMR. To cope with the DBAs, passive decay heat removal system is designed. Water cooled PDHR system shows simple layout, but has CCF with reactor systems and cannot cover all DBAs. On the other hand, air cooled PDHR system with two-phase closed thermosyphon shows high reliability due to minimized CCF and is able to cope with all DBAs. Therefore, the PDHR system of MMR will follows the air-cooled PDHR system and the air cooled system will be explored

Removal of contaminated asphalt layers by using heat generating powder metallic systems

International Nuclear Information System (INIS)

Barinov, A.S.; Karlina, O.K.; Ojovan, M.I.

1996-01-01

Heat generating systems on the base of powder metallic fuel were used for the removal of contaminated asphalt layers. Decontamination of spots which had complex geometric form was performed. Asphalt layers with deep contamination were removed essentially all radionuclides being retained in asphalt residue. Only a small part (1 - 2 %) of radionuclides could pass to combustion slag. No radionuclides were detected in aerosol-gas phase during decontamination process

Safety analysis of increase in heat removal from reactor coolant system with inadvertent operation of passive residual heat removal at no load conditions

Energy Technology Data Exchange (ETDEWEB)

Shao, Ge; Cao, Xuewu [School of Mechanical and Engineering, Shanghai Jiao Tong University, Shanghai (China)

2015-06-15

The advanced passive pressurized water reactor (PWR) is being constructed in China and the passive residual heat removal (PRHR) system was designed to remove the decay heat. During accident scenarios with increase of heat removal from the primary coolant system, the actuation of the PRHR will enhance the cooldown of the primary coolant system. There is a risk of power excursion during the cooldown of the primary coolant system. Therefore, it is necessary to analyze the thermal hydraulic behavior of the reactor coolant system (RCS) at this condition. The advanced passive PWR model, including major components in the RCS, is built by SCDAP/RELAP5 code. The thermal hydraulic behavior of the core is studied for two typical accident sequences with PRHR actuation to investigate the core cooling capability with conservative assumptions, a main steam line break (MSLB) event and inadvertent opening of a steam generator (SG) safety valve event. The results show that the core is ultimately shut down by the boric acid solution delivered by Core Makeup Tank (CMT) injections. The effects of CMT boric acid concentration and the activation delay time on accident consequences are analyzed for MSLB, which shows that there is no consequential damage to the fuel or reactor coolant system in the selected conditions.

Intensified nitrogen and phosphorus removal in a novel electrolysis-integrated tidal flow constructed wetland system.

Science.gov (United States)

Ju, Xinxin; Wu, Shubiao; Zhang, Yansheng; Dong, Renjie

2014-08-01

A novel electrolysis-integrated tidal flow constructed wetland (CW) system was developed in this study. The dynamics of intensified nitrogen and phosphorus removal and that of hydrogen sulphide control were evaluated. Ammonium removal of up to 80% was achieved with an inflow concentration of 60 mg/L in wetland systems with and without electrolysis integration. Effluent nitrate concentration decreased from 2 mg/L to less than 0.5 mg/L with the decrease in current intensity from 1.5 mA/cm(2) to 0.57 mA/cm(2) in the electrolysis-integrated wetland system, thus indicating that the current intensity of electrolysis plays an important role in nitrogen transformations. Phosphorus removal was significantly enhanced, exceeding 95% in the electrolysis-integrated CW system because of the in-situ formation of a ferric iron coagulant through the electro-dissolution of a sacrificial iron anode. Moreover, the electrolyzed wetland system effectively inhibits sulphide accumulation as a result of a sulphide precipitation coupled with ferrous-iron electro-dissolution and/or an inhibition of bacterial sulphate reduction under increased aerobic conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Nitrogen and phosphorus removed from a subsurface flow multi-stage filtration system purifying agricultural runoff.

Science.gov (United States)

Zhao, Yaqi; Huang, Lei; Chen, Yucheng

2018-07-01

Agricultural nonpoint source pollution has been increasingly serious in China since the 1990s. The main causes were excessive inputs of nitrogen fertilizer and pesticides. A multi-stage filtration system was built to test the purification efficiencies and removal characteristics of nitrogen and phosphorus when treating agricultural runoff. Simulated runoff pollution was prepared by using river water as source water based on the monitoring of local agricultural runoff. Experimental study had been performed from September to November 2013, adopting 12 h for flooding and 12 h for drying. The results showed that the system was made adaptive to variation of inflow quality and quantity, and had good removal for dissolved total nitrogen, total nitrogen, dissolved total phosphorus (DTP), and total phosphorus, and the average removal rate was 27%, 36%, 32%, and 48%, respectively. Except nitrate ([Formula: see text]), other forms of nitrogen and phosphorus all decreased with the increase of stages. Nitrogen was removed mainly in particle form the first stage, and mostly removed in dissolved form the second and third stage. Phosphorus was removed mainly in particulate during the first two stages, but the removal of particulate phosphorus and DTP were almost the same in the last stage. An approximate logarithmic relationship between removal loading and influent loading to nitrogen and phosphorus was noted in the experimental system, and the correlation coefficient was 0.78-0.94. [Formula: see text]: ammonium; [Formula: see text]: nitrite; [Formula: see text]: nitrate; DTN: dissolved total nitrogen; TN: total nitrogen; DTP: dissolved total phosphorus; TP: total phosphorus; PN: particulate nitrogen; PP: particulate phosphorus.

An efficient venturi scrubber system to remove submicron particles in exhaust gas.

Science.gov (United States)

Tsai, Chuen-Jinn; Lin, Chia-Hung; Wang, Yu-Min; Hunag, Cheng-Hsiung; Li, Shou-Nan; Wu, Zong-Xue; Wang, Feng-Cai

2005-03-01

An efficient venturi scrubber system making use of heterogeneous nucleation and condensational growth of particles was designed and tested to remove fine particles from the exhaust of a local scrubber where residual SiH4 gas was abated and lots of fine SiO2 particles were generated. In front of the venturi scrubber, normal-temperature fine-water mist mixes with high-temperature exhaust gas to cool it to the saturation temperature, allowing submicron particles to grow into micron sizes. The grown particles are then scrubbed efficiently in the venturi scrubber. Test results show that the present venturi scrubber system is effective for removing submicron particles. For SiO2 particles greater than 0.1microm, the removal efficiency is greater than 80-90%, depending on particle concentration. The corresponding pressure drop is relatively low. For example, the pressure drop of the venturi scrubber is approximately 15.4 +/- 2.4 cm H2O when the liquid-to-gas ratio is 1.50 L/m3. A theoretical calculation has been conducted to simulate particle growth process and the removal efficiency of the venturi scrubber. The theoretical results agree with the experimental data reasonably well when SiO2 particle diameter is greater than 0.1 microm.

Alternate particle removal technologies for the Airborne Activity Confinement System at the Savannah River Site

International Nuclear Information System (INIS)

Brockmann, J.E.; Adkins, C.L.J.; Gelbard, F.

1991-09-01

This report presents a review of the filtration technologies available for the removal of particulate material from a gas stream. It was undertaken to identify alternate filtration technologies that may be employed in the Airborne Activity Confinement System (AACS) at the Savannah River Plant. This report is organized into six sections: (1) a discussion of the aerosol source term and its definition, (2) a short discussion of particle and gaseous contaminant removal mechanisms, (3) a brief overview of particle removal technologies, (4) a discussion of the existing AACS and its potential shortcomings, (5) an enumeration of issues to be addressed in upgrading the AACS, and, (6) a detailed discussion of the identified technologies. The purpose of this report is to identity available options to the existing particle removal system. This system is in continuous operation during routine operation of the reactor. As will be seen, there are a number of options and the selection of any technology or combination of technologies will depend on the design aerosol source term (yet to be appropriately defined) as well as the flow requirements and configuration. This report does not select a specific technology. It focuses on particulate removal and qualitatively on the removal of radio-iodine and mist elimination. Candidate technologies have been selected from industrial and nuclear gas cleaning applications

Study on grey theoretical model of passive residual heat removal system

International Nuclear Information System (INIS)

Zhou Tao; Yang Ruichang; Su, G.H.; Jia Dounan; Sugiyama, K.

2004-01-01

Natural Circulation Passive Residual Heat Removal System is treated as a Grey System by taking into account of its complexity and uncertainty of effect for factors each other. The magnitude and degree of some factors are confirmed by grey incidence analysis method; The one-one relationship of some variables is built by GM (1, 1) model; The relationship between key factor and other effect factors is built (1, 4) model. Grey model shows its more advantage of precision through comparing with multivariate model. (author)

Removal of polycyclic aromatic hydrocarbons (PAHs) from textile dyeing sludge by ultrasound combined zero-valent iron/EDTA/Air system.

Science.gov (United States)

Man, Xiaoyuan; Ning, Xun-An; Zou, Haiyuan; Liang, Jieying; Sun, Jian; Lu, Xingwen; Sun, Jiekui

2018-01-01

This paper proposes a combined ultrasound (US) and zero-valent iron/EDTA/Air (ZEA) system to remove polycyclic aromatic hydrocarbons (PAHs) from textile dyeing sludge. The removal efficiencies of 16 PAHs using ZEA, US/Air (air injected into the US process), and US/ZEA treatments were investigated, together with the effects of various operating parameters. The enhanced mechanisms of US and the role of reactive oxygen species (ROS) in removing PAHs in the US/ZEA system were explored. Results showed that only 42.5% and 32.9% of ∑16 PAHs were removed by ZEA and US/Air treatments respectively, whereas 70.1% were removed by US/ZEA treatment, (with favorable operating conditions of 2.0 mM EDTA, 15 g/L ZVI, and 1.08 w/cm 3 ultrasonic density). The US/ZEA system could be used with a wide pH range. US led to synergistic improvement of PAHs removal in the ZEA system by enhancing sludge disintegration to release PAHs and promoting ZVI corrosion and oxygen activation. In the US/ZEA system, PAHs could be degraded by ROS (namely OH, O 2 - /HO 2 , and Fe(IV)) and adsorbed by ZVI, during which the ROS made the predominant contribution. This study provides important insights into the application of a US/ZEA system to remove PAHs from sludge. Copyright © 2017 Elsevier Ltd. All rights reserved.

Removal of micro-organisms in a small-scale hydroponics wastewater treatment system.

Science.gov (United States)

Ottoson, J; Norström, A; Dalhammar, G

2005-01-01

To measure the microbial removal capacity of a small-scale hydroponics wastewater treatment plant. Paired samples were taken from untreated, partly-treated and treated wastewater and analysed for faecal microbial indicators, i.e. coliforms, Escherichia coli, enterococci, Clostridium perfringens spores and somatic coliphages, by culture based methods. Escherichia coli was never detected in effluent water after >5.8-log removal. Enterococci, coliforms, spores and coliphages were removed by 4.5, 4.1, 2.3 and 2.5 log respectively. Most of the removal (60-87%) took place in the latter part of the system because of settling, normal inactivation (retention time 12.7 d) and sand filtration. Time-dependent log-linear removal was shown for spores (k = -0.17 log d(-1), r(2) = 0.99). Hydroponics wastewater treatment removed micro-organisms satisfactorily. Investigations on the microbial removal capacity of hydroponics have only been performed for bacterial indicators. In this study it has been shown that virus and (oo)cyst process indicators were removed and that hydroponics can be an alternative to conventional wastewater treatment.

A multi-process phytoremediation system for removal of polycyclic aromatic hydrocarbons from contaminated soils

International Nuclear Information System (INIS)

Huang Xiaodong; El-Alawi, Yousef; Penrose, Donna M.; Glick, Bernard R.; Greenberg, Bruce M.

2004-01-01

To improve phytoremediation processes, multiple techniques that comprise different aspects of contaminant removal from soils have been combined. Using creosote as a test contaminant, a multi-process phytoremediation system composed of physical (volatilization), photochemical (photooxidation) and microbial remediation, and phytoremediation (plant-assisted remediation) processes was developed. The techniques applied to realize these processes were land-farming (aeration and light exposure), introduction of contaminant degrading bacteria, plant growth promoting rhizobacteria (PGPR), and plant growth of contaminant-tolerant tall fescue (Festuca arundinacea). Over a 4-month period, the average efficiency of removal of 16 priority PAHs by the multi-process remediation system was twice that of land-farming, 50% more than bioremediation alone, and 45% more than phytoremediation by itself. Importantly, the multi-process system was capable of removing most of the highly hydrophobic, soil-bound PAHs from soil. The key elements for successful phytoremediation were the use of plant species that have the ability to proliferate in the presence of high levels of contaminants and strains of PGPR that increase plant tolerance to contaminants and accelerate plant growth in heavily contaminated soils. The synergistic use of these approaches resulted in rapid and massive biomass accumulation of plant tissue in contaminated soil, putatively providing more active metabolic processes, leading to more rapid and more complete removal of PAHs. - Persistent PAH contaminants in soils can be removed more completely and rapidly by using multiple remediation processes

Regenerating an Arsenic Removal Iron-Based Adsorptive Media System, Part 2: Performance and Cost

Science.gov (United States)

The replacement of exhausted, adsorptive media used to remove arsenic from drinking water accounts for approximately 80% of the total operational and maintenance (O/M) costs of this commonly used small system technology. The results of three, full scale system studies of an on-s...

URANIUM REMOVAL FROM DRINKING WATER USING A SMALL FULL-SCALE SYSTEM

Science.gov (United States)

This report presents background and history of water quality, the basis for design and nine months of actual operating data for a small, full-scale strong-base ion exchange system that is used to remove uranium from a water supply serving a school in Jefferson County, CO. Informa...

Evaporation and condensation devices for passive heat removal systems in nuclear power engineering

International Nuclear Information System (INIS)

Gershuni, A.N.; Pis'mennyj, E.N.; Nishchik, A.P.

2016-01-01

The paper justifies advantages of evaporation and condensation heat transfer devices as means of passive heat removal and thermal shielding in nuclear power engineering. The main thermophysical factors that limit heat transfer capacity of evaporation and condensation systems have been examined in the research. The results of experimental studies of heat engineering properties of elongated (8-m) vertically oriented evaporation and condensation devices (two-phase thermosyphons), which showed a high enough heat transfer capacity, as well as stability and reliability both in steady state and in start-up modes, are provided. The paper presents the examples of schematic designs of evaporation and condensation systems for passive heat removal and thermal shielding in application to nuclear power equipment

Computer Simulation and Modeling of CO2 Removal Systems for Exploration 2013-2014

Science.gov (United States)

Coker, R.; Knox, J.; Gomez, C.

2015-01-01

The Atmosphere Revitalization Recovery and Environmental Monitoring (ARREM) project was initiated in September of 2011 as part of the Advanced Exploration Systems (AES) program. Under the ARREM project and the follow-on Life Support Systems (LSS) project, testing of sub-scale and full-scale systems has been combined with multiphysics computer simulations for evaluation and optimization of subsystem approaches. In particular, this paper will describes the testing and 1-D modeling of the combined water desiccant and carbon dioxide sorbent subsystems of the carbon dioxide removal assembly (CDRA). The goal is a full system predictive model of CDRA to guide system optimization and development.

Removal of trace organic contaminants by a membrane bioreactor-granular activated carbon (MBR-GAC) system.

Science.gov (United States)

Nguyen, Luong N; Hai, Faisal I; Kang, Jinguo; Price, William E; Nghiem, Long D

2012-06-01

The removal of trace organics by a membrane bioreactor-granular activated carbon (MBR-GAC) integrated system were investigated. The results confirmed that MBR treatment can be effective for the removal of hydrophobic (log D>3.2) and readily biodegradable trace organics. The data also highlighted the limitation of MBR in removing hydrophilic and persistent compounds (e.g. carbamazepine, diclofenac, and fenoprop) and that GAC could complement MBR very well as a post-treatment process. The MBR-GAC system showed high removal of all selected trace organics including those that are hydrophilic and persistent to biological degradation at up to 406 bed volumes (BV). However, over an extended period, breakthrough of diclofenac was observed after 7320 BV. This suggests that strict monitoring should be applied over the lifetime of the GAC column to detect the breakthrough of hydrophilic and persistent compounds which have low removal by MBR treatment. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Experimental investigation on improving the removal effect of WFGD system on fine particles by heterogeneous condensation

Energy Technology Data Exchange (ETDEWEB)

Bao, Jingjing; Yang, Linjun; Yan, Jinpei; Xiong, Guilong; Shen, Xianglin [Southeast Univ., Nanjing (China). School of Energy and Environment

2013-07-01

Heterogeneous condensation of water vapor as a preconditioning technique for the removal of fine particles from flue gas was investigated experimentally in a wet flue gas desulfurization (WFGD) system. A supersaturated vapor phase, necessary for condensational growth of fine particles, was achieved in the SO{sub 2} absorption zone and at the top of the wet FGD scrubber by adding steam in the gas inlet and above the scrubbing liquid inlet of the scrubber, respectively. The condensational grown droplets were then removed by the scrubbing liquid and a high-efficiency demister. The results show that the effectiveness of the WFGD system for removal of fine particles is related to the SO{sub 2} absorbent and the types of scrubber employed. Despite a little better effectiveness for the removal of fine particles in the rotating-stream-tray scrubber at the same liquid-to-gas ratio, The similar trends are obtained between the spray scrubber and rotating-stream-tray scrubber. Due to the formation of aerosol particles in the limestone and ammonia-based FGD processes, the fine particle removal efficiencies are lower than those for Na{sub 2}CO{sub 3} and water. The performance of the WFGD system for removal of fine particles can be significantly improved for both steam addition cases, for which the removal efficiency increases with increasing amount of added steam. A high liquid to gas ratio is beneficial for efficient removal of fine particles by heterogeneous condensation of water vapor.

[Treatment of removable partial dentures. 2. Causes and consequences of a reduced occlusal system].

Science.gov (United States)

Witter, D J; Barèl, J C; de Baat, C; Keltjens, H M A M; Creugers, N H J

2011-01-01

The occlusal system is part of the orofacial system and consists of the maxillary and mandibular alveolar ridge and teeth which are occluding or not or the removable denture teeth. The most prevalent causes of loss of teeth are insufficient oral self care or inadequate professional oral healthcare service. A reduced dentition can be described in terms of diastemas in the anterior region and number of occluding pairs of (pre)molars, differentiated as interrupted or shortened dental arches. Characteristic of a healthy functional occlusal system are the absence of pathology and the possibility to practice all oral functions without inconvenience. The consequences of a reduced occlusal system may be overload and/or migration of teeth, mandibular instability, and impaired esthetics and chewing function. Morphological and functional alterations can be considered to be adaptations to changed situations or to be pathological. The distinction between adaptation and pathology cannot be sharply defined. If prosthetic replacement of teeth is needed, the trend is to avoid removable partial dentures.

Removal of nitrogen by a layered soil infiltration system during intermittent storm events.

Science.gov (United States)

Cho, Kang Woo; Song, Kyung Guen; Cho, Jin Woo; Kim, Tae Gyun; Ahn, Kyu Hong

2009-07-01

The fates of various nitrogen species were investigated in a layered biological infiltration system under an intermittently wetting regime. The layered system consisted of a mulch layer, coarse soil layer (CSL), and fine soil layer (FSL). The effects of soil texture were assessed focusing on the infiltration rate and the removal of inorganic nitrogen species. The infiltration rate drastically decreased when the uniformity coefficient was larger than four. The ammonium in the synthetic runoff was shown to be removed via adsorption during the stormwater dosing and nitrification during subsequent dry days. Stable ammonium adsorption was observed when the silt and clay content of CSL was greater than 3%. This study revealed that the nitrate leaching was caused by nitrification during dry days. Various patterns of nitrate flushing were observed depending on the soil configuration. The washout of nitrate was more severe as the silt/clay content of the CSL was greater. However, proper layering of soil proved to enhance the nitrate removal. Consequently, a strictly sandy CSL over FSL with a silt and clay content of 10% was the best configuration for the removal of ammonium and nitrate.

Erosion of Embolization Coils into the Renal Collecting System: Removal with Prone Transradial Renal Arteriography and Nephroscopy.

Science.gov (United States)

Srinivasa, Ravi N; Chick, Jeffrey Forris Beecham; Hage, Anthony; Ramamurthi, Aishu; Wolf, J Stuart; Gemmete, Joseph J; Dauw, Casey A

2017-10-01

Removal of embolization coils eroded into the renal collecting system poses a risk of hemorrhage, which may need to be addressed with arteriography and embolization at the time of treatment. The purpose of this report is to describe a novel approach, by which prone percutaneous nephroscopic coil retrieval is coupled with simultaneous prone transradial renal arterial access to mitigate this potential complication. A retrospective chart review of the electronic medical record systems was performed from January 2008 to May 2017 to identify patients who had undergone percutaneous removal of embolization coils eroded into the renal collecting system. Patients who had migration of embolization coils into the renal collecting system who were symptomatic with pain, hydronephrosis, or infection were considered for inclusion. Patients who had coil migration, but were asymptomatic were not offered removal. Patient demographics and case characteristics were examined as were operative outcomes. A total of three patients fulfilled the study criteria. Migrated embolization coils were able to be effectively removed in all patients. Of the patients, two underwent simultaneous prone transradial renal arteriography with placement of an occlusion balloon catheter into the segmental artery of interest. In one patient, significant arterial bleeding was encountered after coil removal, which was effectively addressed with simultaneous arteriography and glue embolization. Erosion of embolization coils into the renal collecting system, while rare, may be a significant long-term complication of coil embolization. Combining nephroscopy with prone transradial arteriography in preparation for procedure-associated hemorrhage may make removal of migrated coils safer.

Removal of COD, phenols and ammonium from Lurgi coal gasification wastewater using A2O-MBR system

International Nuclear Information System (INIS)

Wang, Zixing; Xu, Xiaochen; Gong, Zheng; Yang, Fenglin

2012-01-01

Highlights: ► Anaerobic–anoxic–aerobic MBR system treated the coal gasification wastewater. ► COD removal rate was 97.4% with effluent concentration less than 100 mg/L. ► NH 4 + -N removal rate was 92.8% with effluent concentration less than 12 mg/L. ► HRT and recycle ratio strongly affected the performance of the system. ► GC/MS analysis found refractory organic removal in anaerobic and anoxic stage. - Abstract: As a typical industrial wastewater, coal gasification wastewater has poor biodegradability and high toxicity. In this paper, a laboratory-scale anaerobic–anoxic–oxic membrane reactor (A 2 O-MBR) system was developed to investigate the treatment ability of coal gasification wastewater. The removal capacity of each pollutants used in this system were determined at different hydraulic residence times (HRT) and mixed liquor recycle ratios (R). The experimental results showed that this system could effectively deal with COD and phenol removal and remain in a stable level when the operational parameters altered, while the nitrification was sensitive to operational conditions. The best performance was obtained at HRT of 48 h and R of 3. The maximum removal efficiencies of COD, NH 4 + -N and phenols were 97.4%, 92.8% and 99.7%, with final concentrations in the effluent of 71 mg/L, 9.6 mg/L and 3 mg/L, respectively. Organics degradation and transformation were analyzed by GC/MS and it was found that anaerobic process played an important role in degradation of refractory compounds.

Simulation and optimisation of the data acquisition system for tritium removal pilot plant

International Nuclear Information System (INIS)

Retevoi, Carmen Maria; Stefan, Iuliana; Balteanu, Ovidiu; Stefan, Liviu

2004-01-01

Optimization and simulation of systems especially in science and engineering can help to reduce risk and cost of design and testing processes. A huge number of codes has been developed to support modeling and simulation efforts. All of these software tools support the use of one or more mathematical model classes. Despite all of these efforts, it is hard to find simulation software, which is capable of combining several model classes in a real industry standard environment. The paper presents a simulation software product for controlling and data acquisition system of cryogenic installation process in the tritium removal pilot plant, using an industry standard programming environment widely applied to data acquisition, process control and data visualization, namely LabView. One of the problems in a tritium separation installation is controlling the temperature. To solve this problem it is necessary to develop a simulation system which includes the mathematical model for cryogenic distillation. Also with this simulation system we can approach the safety system which ensures the monitoring of radiations and toxic gases from installation. All elements used in controlling, modeling and simulation of the process, as well as, in the datalogging and supervisory control module from tritium removal installation are new. (authors)

Experimental research on passive residual heat remove system for advanced PWR

International Nuclear Information System (INIS)

Huang Yanping; Zhuo Wenbin; Yang Zumao; Xiao Zejun; Chen Bingde

2003-01-01

The experimental and qualified results of MISAP in the research of passive residual heat remove system of advanced PWR performed in the Bubble physics and natural circulation laboratory in Nuclear Power Institute of China in the past ten years is overviewed. Further researches for engineering research and design are also suggested

Efficient TEA CO2 laser based coating removal system

CSIR Research Space (South Africa)

Prinsloo, FJ

2007-04-01

Full Text Available stream_source_info Prinsloo_2007.pdf.txt stream_content_type text/plain stream_size 11617 Content-Encoding UTF-8 stream_name Prinsloo_2007.pdf.txt Content-Type text/plain; charset=UTF-8 Efficient TEA CO2 laser based... by keeping energy density below the damage threshold. The advantage of a pulsed TEA CO2 laser system is that a laser frequency and temporal profile can be chosen to maximize paint removal and concurrently minimize substrate damage. To achieve...

Assessment of the advantages of a residual heat removal system inside the reactor pressure vessel

Energy Technology Data Exchange (ETDEWEB)

Gautier, G.M. [Commissariat a l`Energie Atomique, Saint-Paul-Lez-Durance (France)

1995-09-01

In the framework of research on diversified means for removing residual heat from pressurized water reactors, the CEA is studying a passive system called RRP (Refroidissement du Reacteur au Primaire, or primary circuit cooling system). This system consists of integrated heat-exchangers and a layout of the internal structures so as to obtain convection from the primary circuit inside the vessel, whatever the state of the loops. This system is operational for all primary circuit temperatures and pressures, as well as for a wide range of conditions: such as independent from the state of the loops, low volume of water in the primary circuit, compatibility with either a passive or an active operation mode, and compatibility with any other decay heat removal systems. This paper presents an evaluation of the performance of the RRP system in the event of a small primary circuit break in a totally passive operation mode without the intervention of any another system. The results of this evaluation show the potential interest of such a system: a clear increase of the time-delay for the implementation of a low pressure safety injection system and no need for the use of a high pressure safety injection system.

Performance improvement of the finned passive PVT system using reflectors like removable insulation covers

International Nuclear Information System (INIS)

Ziapour, Behrooz M.; Palideh, Vahid; Mokhtari, Farhad

2016-01-01

Highlights: • A passive PVT system means the combination of a PV panel and a compact solar water heater. • Comparative study was done on performance characteristics in passive and hybrid PVT systems. • Reflectors effects on performance of a finned passive PVT system were numerically studied. • Results show that the finned passive PVT system has higher performance than the hybrid type. • Reflectors reduce the night heat losses and increase the solar radiation rate on PVT system. - Abstract: A passive photovoltaic–thermal system (PVT) is the combination of a photovoltaic (PV) panel and a compact solar water heater for co-generation of heat and electricity. This system bears considerable heat losses to ambient, particularly at noncollection times. One simple way to overcome this problem is to use a removable insulation cover on the collector's outer glazing. In this paper, the effects of the reflectors on day and night performance of a finned passive PVT system were numerically studied. At nonenergy collection time, the reflectors can turn and cover the collector cover glass as a nonconductor material. Simulation results showed that the reflectors reduce the night heat losses and increase the solar radiation rate on the absorber plate. The use of removable insulation reflectors resulted to saving extra sensibly thermal energy. Also, the solar cells power generation (P_s_c), in the case of reflectors installed, was reinforced.

Effect of operational cycle time length on nitrogen removal in an alternating oxidation ditch system.

Science.gov (United States)

Mantziaras, I D; Stamou, A; Katsiri, A

2011-06-01

This paper refers to nitrogen removal optimization of an alternating oxidation ditch system through the use of a mathematical model and pilot testing. The pilot system where measurements have been made has a total volume of 120 m(3) and consists of two ditches operating in four phases during one cycle and performs carbon oxidation, nitrification, denitrification and settling. The mathematical model consists of one-dimensional mass balance (convection-dispersion) equations based on the IAWPRC ASM 1 model. After the calibration and verification of the model, simulation system performance was made. Optimization is achieved by testing operational cycles and phases with different time lengths. The limits of EU directive 91/271 for nitrogen removal have been used for comparison. The findings show that operational cycles with smaller time lengths can achieve higher nitrogen removals and that an "equilibrium" between phase time percentages in the whole cycle, for a given inflow, must be achieved.

[Treatment of removable partial dentures. 2. Causes and consequences of a reduced occlusal system

NARCIS (Netherlands)

Witter, D.J.; Barel, J.C.; Baat, C. de; Keltjens, H.M.A.M.; Creugers, N.H.J.

2011-01-01

The occlusal system is part of the orofacial system and consists of the maxillary and mandibular alveolar ridge and teeth which are occluding or not or the removable denture teeth. The most prevalent causes of loss of teeth are insufficient oral self care or inadequate professional oral healthcare

Optimization of arsenic removal water treatment system through characterization of terminal electron accepting processes.

Science.gov (United States)

Upadhyaya, Giridhar; Clancy, Tara M; Brown, Jess; Hayes, Kim F; Raskin, Lutgarde

2012-11-06

Terminal electron accepting process (TEAP) zones developed when a simulated groundwater containing dissolved oxygen (DO), nitrate, arsenate, and sulfate was treated in a fixed-bed bioreactor system consisting of two reactors (reactors A and B) in series. When the reactors were operated with an empty bed contact time (EBCT) of 20 min each, DO-, nitrate-, sulfate-, and arsenate-reducing TEAP zones were located within reactor A. As a consequence, sulfate reduction and subsequent arsenic removal through arsenic sulfide precipitation and/or arsenic adsorption on or coprecipitation with iron sulfides occurred in reactor A. This resulted in the removal of arsenic-laden solids during backwashing of reactor A. To minimize this by shifting the sulfate-reducing zone to reactor B, the EBCT of reactor A was sequentially lowered from 20 min to 15, 10, and 7 min. While 50 mg/L (0.81 mM) nitrate was completely removed at all EBCTs, more than 90% of 300 μg/L (4 μM) arsenic was removed with the total EBCT as low as 27 min. Sulfate- and arsenate-reducing bacteria were identified throughout the system through clone libraries and quantitative PCR targeting the 16S rRNA, dissimilatory (bi)sulfite reductase (dsrAB), and dissimilatory arsenate reductase (arrA) genes. Results of reverse transcriptase (RT) qPCR of partial dsrAB (i.e., dsrA) and arrA transcripts corresponded with system performance. The RT qPCR results indicated colocation of sulfate- and arsenate-reducing activities, in the presence of iron(II), suggesting their importance in arsenic removal.

Methyl-orange and cadmium simultaneous removal using fly ash and photo-Fenton systems

International Nuclear Information System (INIS)

Visa, Maria; Duta, Anca

2013-01-01

Highlights: ► The mixed substrates of FA-M + TiO 2 proved to be highly efficient in adsorption. ► FA-M + photo-Fenton are a low-cost material for advanced treatment of wastewater. ► The adsorbed MO may act as a complexion agent, increasing the affinity for metals. ► Dye removal by photodegradation is the favourable mechanism compared to adsorption. -- Abstract: Wastewaters resulting from the textile and dye finishing industries need complex treatment for efficient removal of colour and other compounds existent in the dyeing and rising baths (heavy metals, surfactants, equalizers, etc.). Modified fly ash (FA) mixed with TiO 2 photocatalyst represent a viable option for simultaneous removal of dyes and heavy metals, and the optimized conditions are discussed in this paper for synthetic wastewaters containing methyl-orange (MO) and cadmium. For a cost-effective dye removal process, further tests were done, replacing the photocatalyst with a (photo)Fenton system. The optimized technological parameters (contact time, amount of fly ash and amount of Fe 2+ /H 2 O 2 ) allow to reach removal efficiencies up to 88% for the heavy metal and up to 70% for the dye. The adsorption mechanisms and the process kinetic are discussed, also considering the possibility of in situ generation of the Fenton system, due to the fly ash composition

Methyl-orange and cadmium simultaneous removal using fly ash and photo-Fenton systems

Energy Technology Data Exchange (ETDEWEB)

Visa, Maria, E-mail: visamro2000@yahoo.com [Transilvania University of Brasov, Department of Renewable Energy Systems and Recycling, Eroilor 29, 500036 Brasov (Romania); Duta, Anca, E-mail: a.duta@unitbv.ro [Transilvania University of Brasov, Department of Renewable Energy Systems and Recycling, Eroilor 29, 500036 Brasov (Romania)

2013-01-15

Highlights: ► The mixed substrates of FA-M + TiO{sub 2} proved to be highly efficient in adsorption. ► FA-M + photo-Fenton are a low-cost material for advanced treatment of wastewater. ► The adsorbed MO may act as a complexion agent, increasing the affinity for metals. ► Dye removal by photodegradation is the favourable mechanism compared to adsorption. -- Abstract: Wastewaters resulting from the textile and dye finishing industries need complex treatment for efficient removal of colour and other compounds existent in the dyeing and rising baths (heavy metals, surfactants, equalizers, etc.). Modified fly ash (FA) mixed with TiO{sub 2} photocatalyst represent a viable option for simultaneous removal of dyes and heavy metals, and the optimized conditions are discussed in this paper for synthetic wastewaters containing methyl-orange (MO) and cadmium. For a cost-effective dye removal process, further tests were done, replacing the photocatalyst with a (photo)Fenton system. The optimized technological parameters (contact time, amount of fly ash and amount of Fe{sup 2+}/H{sub 2}O{sub 2}) allow to reach removal efficiencies up to 88% for the heavy metal and up to 70% for the dye. The adsorption mechanisms and the process kinetic are discussed, also considering the possibility of in situ generation of the Fenton system, due to the fly ash composition.

System for chemical decontamination of nuclear reactor primary systems

International Nuclear Information System (INIS)

Schlonski, J.S.; McGiure, M.F.; Corpora, G.J.

1992-01-01

This patent describes a method of chemically decontaminating a nuclear reactor primary system, having a residual heat removal system with one or more residual heat removal heat exchangers, each having an upstream and a downstream side, at or above ambient pressure. It comprises: injecting decontamination chemicals using an injection means; circulating the injected decontamination chemicals throughout the primary system; directing the circulated decontamination chemicals and process fluids to a means for removing suspended solids and dissolved materials after the circulated chemicals and process fluids have passed through the residual heat removal heat exchanger; decontaminating the process fluids; and feeding the decontaminated process fluids to the injection means. This patent also describes a chemical decontamination system for use at, or above, ambient pressure in a nuclear reactor primary system having a residual heat removal system. It comprises: means for injecting decontamination chemicals into the primary system; means for removing dissolved and suspended materials and decontamination chemicals from the primary system; one or more residual heat removal pumps; means located downstream of one of the residual heat removal heat exchangers; and a return line connecting the means

Comparative efficiency of final endodontic cleansing procedures in removing a radioactive albumin from root canal systems

International Nuclear Information System (INIS)

Cecic, P.A.; Peters, D.D.; Grower, M.F.

1984-01-01

Fifty-six teeth were initially instrumented, with the use of seven irrigants or irrigant combinations, and filled with radioactive albumin. The study then showed the relative ability of three final endodontic procedures (copious reirrigation with saline solution, drying with paper points, and reassuring patency of the canal with the final instrument) to remove the albumin. Even after copious irrigation, each additional procedure removed statistically significant amounts of albumin. Alternating an organic solvent and an inorganic solvent did appear to leave the canal system in the optimal condition for final cleansing procedures. The study then correlated the relative efficiency of irrigation alone versus instrumentation plus irrigation in removing the remaining albumin from the canal systems. Reinstrumentation plus copious irrigation removed significantly more albumin than copious irrigation alone

Assessment of the advantages of a residual heat removal system inside the reactor pressure vessel

International Nuclear Information System (INIS)

Gautier, G.M.

1995-01-01

In the framework of research on diversified means for removing the residual heat from pressurized water reactors, the CEA is studying a passive system called RRP (Refroidissement du Reacteur au Primaire, or primary circuit cooling system), which includes integrated heat-exchangers and a layout of the internal structures so as to obtain convection from the primary circuit inside the vessel, whatever the state of the loops. This system is operational for all primary circuit temperatures and pressures, as well as for a wide range of conditions: it is independent of the state of the loops, even if the volume of water in the primary circuit is small, it is compatible with either a passive or an active operation mode, and compatible with any other decay heat removal systems. An evaluation is presented here of the performance of the RRP system in the event of a small primary circuit break in a totally passive operation mode without the intervention of another system. The results of this evaluation show the interest of such a system: a clear increase of the time-delay for the implementation of a low pressure safety injection system, no need for the use of a high pressure safety injection system. (author). 4 refs., 7 figs., 1 tab

Design Strategies and Preliminary Prototype for a Low-Cost Arsenic Removal System for Rural Bangladesh

Energy Technology Data Exchange (ETDEWEB)

Mathieu, Johanna L.; Gadgil, Ashok J.; Kowolik, Kristin; Qazi, Shefah; Agogino, Alice M.

2009-09-14

Researchers have invented a material called ARUBA -- Arsenic Removal Using Bottom Ash -- that effectively and affordably removes arsenic from Bangladesh groundwater. Through analysis of studies across a range of disciplines, observations, and informal interviews conducted over three trips to Bangladesh, we have applied mechanical engineering design methodology to develop eight key design strategies, which were used in the development of a low-cost, community-scale water treatment system that uses ARUBA to removearsenic from drinking water. We have constructed, tested, and analysed a scale version of the system. Experiments have shown that the system is capable of reducing high levels of arsenic (nearly 600 ppb) to below the Bangladesh standard of 50 ppb, while remaining affordable to people living on less than US$2/day. The system could be sustainably implemented as a public-private partnership in rural Bangladesh.

Sorbent Structural Impacts Due to Humidity on Carbon Dioxide Removal Sorbents for Advanced Exploration Systems

Science.gov (United States)

Watson, David; Knox, James C.; West, Phillip; Stanley, Christine M.; Bush, Richard

2015-01-01

The Life Support Systems Project (LSSP) under the Advanced Exploration Systems (AES) program builds upon the work performed under the AES Atmosphere Resource Recovery and Environmental Monitoring (ARREM) project focusing on the numerous technology development areas. The CO2 removal and associated air drying development efforts are focused on improving the current state-of-the-art system on the International Space Station (ISS) utilizing fixed beds of sorbent pellets by seeking more robust pelletized sorbents, evaluating structured sorbents, and examining alternate bed configurations to improve system efficiency and reliability. A component of the CO2 removal effort encompasses structural stability testing of existing and emerging sorbents. Testing will be performed on dry sorbents and sorbents that have been conditioned to three humidity levels. This paper describes the sorbent structural stability screening efforts in support of the LSS Project within the AES Program.

PANDA experiment and International Standard Problem for passive cooling systems for afterheat removal

International Nuclear Information System (INIS)

Yadigaroglu, G.; Aksan, N.S.

1999-01-01

In the context of OECD/NEA, Paul Scherrer Institut (PSI) is working on an International Standard Problem which is to provide information on the efficiency and use of computer program systems for passive afterheat removal systems. The PANDA test facility of PSI was designed for these investigations. A six-phase PANDA experiment provides a basis for pre-calculation and recalculation of selected phases covering a limited number of system-typical operating states and phenomena. The experiment was specified and carried out in the year under report [de

CLASSIFICATION OF SYSTEMS FOR PASSIVE AFTERHEAT REMOVAL FROM REACTOR CONTAINMENT OF NUCLEAR POWER PLANT WITH WATER-COOLED POWER REACTOR

Directory of Open Access Journals (Sweden)

N. Khaled

2014-01-01

Full Text Available A classification on systems for passive afterheat removal from reactor containment has been developed in the paper.  The classification permits to make a detailed analysis of various concepts pertaining to systems for passive afterheat removal from reactor containment of new generation. The paper considers main classification features of the given systems.

Radium removal for a small community water-supply system. Research report, 1 October 1985-30 September 1987

International Nuclear Information System (INIS)

Mangelson, K.A.

1988-07-01

In 1984, a radium-removal treatment plant was constructed for the small community of Redhill Forest located in the central mountains of Colorado. The treatment plant consists of a process for removing iron and manganese ahead of an ion-exchange process for the removal of radium. The raw water comes from deep wells and has naturally occurring radium and iron concentrations of about 30-40 pCi/L and 7-10 mg/L, respectively. Before the raw water enters the main treatment plant, the raw water is aerated to remove radon gas and carbon dioxide. The unique features of the Redhill Forest Treatment Plant are related to the ways in which the radium removed from the raw water is further treated and eventually disposed of as treatment plant waste. A separate system removes only radium from the backwash/regeneration water of the ion exchange process and the radium is permanently complexed on a Radium Selective Complexer (RSC) resin made by Dow Chemical. The RSC resin containing radium is replaced with virgin resin as needed and the resin waste transported to a permanent final disposal site in Beatty, NV. This report presents a detailed description of the Redhill Forest treatment system and the results of in-depth monitoring of the processes and other factors relating to the overall operation of the radium-removal system. Included are descriptions of modifications made in the plant operation to improve the overall system operation and of the procedures for final disposal of the RSC resin-containing radium

Aging assessment of Residual Heat Removal systems in Boiling Water Reactors

International Nuclear Information System (INIS)

Lofaro, R.J.; Aggarwal, S.

1992-01-01

The effects of aging on Residual Heat Removal systems in Boiling Water Reactors have been studied as part of the Nuclear Plant Aging Research Program. The aging phenomena has been characterized by analyzing operating experience from various national data bases. In addition, actual plant data was obtained to supplement and validate the data base findings

Failure Modes and Effects Analysis (FMEA) of the Residual Heat Removal System

International Nuclear Information System (INIS)

Eggleston, F.T.

1976-01-01

The Residual Heat Removal System (RHRS) transfer heat from the Reactor Coolant System (RCS) to the reactor plant Component Cooling System (CCS) to reduce the temperature of the RCS at a controlled rate during the second part of normal plant cooldown and maintains the desired temperature until the plant is restarted. By the use of an analytic tool, the Failure Modes and Effects Analysis, it is shown that the RHRS, because of its redundant two train design, is able to accommodate any credible component single failure with the only effect being an extension in the required cooldown time, thus demonstrating the reliability of the RHRS to perform its intended function

Heavy metal removal in an UASB-CW system treating municipal wastewater.

Science.gov (United States)

de la Varga, D; Díaz, M A; Ruiz, I; Soto, M

2013-10-01

The objective of the present study was to investigate for the first time the long-term removal of heavy metals (HMs) in a combined UASB-CW system treating municipal wastewater. The research was carried out in a field pilot plant constituted for an up-flow anaerobic sludge bed (UASB) digester as a pretreatment, followed by a surface flow constructed wetland (CW) and finally by a subsurface flow CW. While the UASB showed (pseudo) steady state operational conditions and generated a periodical purge of sludge, CWs were characterised by the progressive accumulation and mineralisation of retained solids. This paper analyses the evolution of HM removal from the water stream over time (over a period of 4.7 year of operation) and the accumulation of HMs in UASB sludge and CW sediments at two horizons of 2.7 and 4.0 year of operation. High removal efficiencies were found for some metals in the following order: Sn > Cr > Cu > Pb > Zn > Fe (63-94%). Medium removal efficiencies were registered for Ni (49%), Hg (42%), and Ag (40%), and finally Mn and As showed negative percentage removals. Removal efficiencies of total HMs were higher in UASB and SF units and lower in the last SSF unit. Copyright © 2013 Elsevier Ltd. All rights reserved.

Investigating the mechanism of clofibric acid removal in Fe0/H2O systems

International Nuclear Information System (INIS)

Ghauch, Antoine; Abou Assi, Hala; Tuqan, Almuthanna

2010-01-01

Since the introduction of iron wall technology, the inherent relationship between contaminant removal and iron corrosion has been mostly attributed to electron transfer from the metal body (direct reduction). This thermodynamically founded premise has failed to explain several experimental facts. Recently, a new concept considering adsorption and co-precipitation as fundamental contaminant removal mechanisms was introduced. This consistent concept has faced very skeptic views and necessarily needs experimental validation. The present work was the first independent attempt to validate the new concept using clofibric acid (CLO) as model compound. For this purpose, a powdered Fe 0 material (Fe 0 ) was used in CLO removal experiments under various experimental conditions. Additional experiments were performed with plated Fe 0 (mFe 0 : Fe 0 /Pd 0 , Fe 0 /Ni 0 ) to support the discussion of removal mechanism. Main investigated experimental variables included: abundance of O 2 , abundance of iron corrosion products (ICPs) and shaking operations. Results corroborated the concept that quantitative contaminant removal in Fe 0 /H 2 O systems occurs within the oxide-film in the vicinity of Fe 0 . Additionally, mixing type and shaking intensity significantly influenced the extent of CLO removal. More importantly, HPLC/MS revealed that the identity of reaction products depends on the extent of iron corrosion or the abundance of ICPs. The investigation of the CLO/Fe 0 /H 2 O system disproved the popular view that direct reduction mediates contaminant removal in the presence of Fe 0 .

Programmable removal of bacterial strains by use of genome-targeting CRISPR-Cas systems.

Science.gov (United States)

Gomaa, Ahmed A; Klumpe, Heidi E; Luo, Michelle L; Selle, Kurt; Barrangou, Rodolphe; Beisel, Chase L

2014-01-28

CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) systems in bacteria and archaea employ CRISPR RNAs to specifically recognize the complementary DNA of foreign invaders, leading to sequence-specific cleavage or degradation of the target DNA. Recent work has shown that the accidental or intentional targeting of the bacterial genome is cytotoxic and can lead to cell death. Here, we have demonstrated that genome targeting with CRISPR-Cas systems can be employed for the sequence-specific and titratable removal of individual bacterial strains and species. Using the type I-E CRISPR-Cas system in Escherichia coli as a model, we found that this effect could be elicited using native or imported systems and was similarly potent regardless of the genomic location, strand, or transcriptional activity of the target sequence. Furthermore, the specificity of targeting with CRISPR RNAs could readily distinguish between even highly similar strains in pure or mixed cultures. Finally, varying the collection of delivered CRISPR RNAs could quantitatively control the relative number of individual strains within a mixed culture. Critically, the observed selectivity and programmability of bacterial removal would be virtually impossible with traditional antibiotics, bacteriophages, selectable markers, or tailored growth conditions. Once delivery challenges are addressed, we envision that this approach could offer a novel means to quantitatively control the composition of environmental and industrial microbial consortia and may open new avenues for the development of "smart" antibiotics that circumvent multidrug resistance and differentiate between pathogenic and beneficial microorganisms. Controlling the composition of microbial populations is a critical aspect in medicine, biotechnology, and environmental cycles. While different antimicrobial strategies, such as antibiotics, antimicrobial peptides, and lytic bacteriophages, offer partial solutions

Process and system for removing impurities from a gas

Science.gov (United States)

Henningsen, Gunnar; Knowlton, Teddy Merrill; Findlay, John George; Schlather, Jerry Neal; Turk, Brian S

2014-04-15

A fluidized reactor system for removing impurities from a gas and an associated process are provided. The system includes a fluidized absorber for contacting a feed gas with a sorbent stream to reduce the impurity content of the feed gas; a fluidized solids regenerator for contacting an impurity loaded sorbent stream with a regeneration gas to reduce the impurity content of the sorbent stream; a first non-mechanical gas seal forming solids transfer device adapted to receive an impurity loaded sorbent stream from the absorber and transport the impurity loaded sorbent stream to the regenerator at a controllable flow rate in response to an aeration gas; and a second non-mechanical gas seal forming solids transfer device adapted to receive a sorbent stream of reduced impurity content from the regenerator and transfer the sorbent stream of reduced impurity content to the absorber without changing the flow rate of the sorbent stream.

Solvent cleaning system and method for removing contaminants from solvent used in resin recycling

Science.gov (United States)

Bohnert, George W [Harrisonville, MO; Hand, Thomas E [Lee's Summit, MO; DeLaurentiis, Gary M [Jamestown, CA

2009-01-06

A two step solvent and carbon dioxide based system that produces essentially contaminant-free synthetic resin material and which further includes a solvent cleaning system for periodically removing the contaminants from the solvent so that the solvent can be reused and the contaminants can be collected and safely discarded in an environmentally safe manner.

Preliminary screening of small-scale domestic wastewater treatment systems for removal of pharmaceutical and personal care products

DEFF Research Database (Denmark)

Matamoros, Victor; Arias, Carlos Alberto; Brix, Hans

2009-01-01

, two biological sand filters, five horizontal subsurface flow and four vertical flow constructed wetlands. As expected, all systems removed TSS and BOD5 efficiently (>95% removal). The PPCP removal efficiencies exceeded 80% with the exception of carbamazepine, diclofenac and ketoprofen because...

Performance of the constructed wetland systems in pollutants removal from hog wastewater

Directory of Open Access Journals (Sweden)

Wallison da Silva Freitas

2010-08-01

Full Text Available The main objective of this work was to evaluate the efficiency of a constructed wetland systems (CWS for pollutants removal, in mono crop and multi crop with three different species of plants, originated from hog wastewater treatment (HW. Therefore, 5 CWS of 24.0 m x 1.1 m x 0.7 m were constructed, sealed with a membrane of polyvinyl chloride (PVC and filled with 0.4 m of small gravel. In CWS1, CWS2 and CWS3 grown to cattail (Typha latifolia L., Alternanthera philoxeroides (Mart. Griseb. and Tifton 85 grass (Cynodon dactylon Pers., respectively. In the bed of CWS4 was planted at 1st third Alternanthera, cattail, in the 2nd third and tifton-85 grass and in the 3rd third of. The CWS5 was not planted and it was used as control. After passing through a filter filled with crushed bagasse of sugar cane, the HW was applied to the CWS in a flow of 0.8 m3 d-1, which corresponded to a hydraulic detention time of 4.8 days. According to the results it was shown that the five CWS(s had statistically nearly the same removal of pollutants, and the average removal efficiency of TSS, COD, BOD and Zn, were 91, 89, 86 and 94%, respectively. Also high removals were obtained concerning the ST, N-total, NH4+ and P-total, with average values of 62, 59, 52 and 50%, respectively. The plants in all planted CWS worked in a similar way maintaining the system efficiency and the non cultivated CWS presented analogous capacity of pollutants removal when compared to the cultivated CWS(s.

Electrically enhanced MBR system for total nutrient removal in remote northern applications.

Science.gov (United States)

Wei, V; Elektorowicz, M; Oleszkiewicz, J A

2012-01-01

Thousands of sparsely populated communities scatter in the remote areas of northern Canada. It is economically preferable to adopt the decentralized systems to treat the domestic wastewater because of the vast human inhabitant distribution and cold climatic conditions. Electro-technologies such as electrofiltration, elctrofloatation, electrocoagulation and electrokinetic separation have been applied in water and conventional wastewater treatment for decades due to the minimum requirements of chemicals as well as ease of operation. The membrane bioreactor (MBR) is gaining popularity in recent years as an alternative water/wastewater treatment technology. However, few studies have been conducted to hyphenate these two technologies. The purpose of this work is to design a novel electrically enhanced membrane bioreactor (EMBR) as an alternative decentralized wastewater treatment system with improved nutrient removal and reduced membrane fouling. Two identical submerged membranes (GE ZW-1 hollow fiber module) were used for the experiment, with one as a control. The EMBR and control MBR were operated for 4 months at room temperature (20 ± 2 °C) with synthetic feed and 2 months at 10 °C with real sewage. The following results were observed: (1) the transmembrane pressure (TMP) increased significantly more slowly in the EMBR and the interval between the cleaning cycles of the EMBR increased at least twice; (2) the dissolved chemical oxygen demand (COD) or total organic carbon (TOC) in the EMBR biomass was reduced from 30 to 51%, correspondingly, concentrations of the extracellular polymeric substances (EPS), the major suspicious membrane foulants, decreased by 26-46% in the EMBR; (3) both control and EMBR removed >99% of ammonium-N and >95% of dissolved COD, in addition, ortho-P removal in the EMBR was >90%, compared with 47-61% of ortho-P removal in the MBR; and (4) the advantage of the EMBR over the conventional MBR in terms of membrane fouling retardation and

Removal of triazine herbicides from aqueous systems by a biofilm reactor continuously or intermittently operated.

Science.gov (United States)

Sánchez-Sánchez, R; Ahuatzi-Chacón, D; Galíndez-Mayer, J; Ruiz-Ordaz, N; Salmerón-Alcocer, A

2013-10-15

The impact of pesticide movement via overland flow or tile drainage water on the quality of receiving water bodies has been a serious concern in the last decades; thus, for remediation of water contaminated with herbicides, bioreaction systems designed to retain biomass have been proposed. In this context, the aim of this study was to evaluate the atrazine and terbutryn biodegradation capacity of a microbial consortium, immobilized in a biofilm reactor (PBR), packed with fragments of porous volcanic stone. The microbial consortium, constituted by four predominant bacterial strains, was used to degrade a commercial formulation of atrazine and terbutryn in the biofilm reactor, intermittently or continuously operated at volumetric loading rates ranging from 44 to 306 mg L(-1) d(-1). The complete removal of both herbicides was achieved in both systems; however, higher volumetric removal rates were obtained in the continuous system. It was demonstrated that the adjuvants of the commercial formulation of the herbicide significantly enhanced the removal of atrazine and terbutryn. Copyright © 2013 Elsevier Ltd. All rights reserved.

Recovery of reactor electrical assemblies using differential de-encapsulation to remove dielectric insulation systems

International Nuclear Information System (INIS)

Hubrig, J.G.; Hammerstone, E.B.

1986-01-01

State-of-the-art de-encapsulation technologies associated with the conventional dielectric insulation systems employed in the construction of electrical coils and power distribution systems do not allow for accurate fatigue/failure analysis or reliable recovery of costly assembly components. Differential de-encapsulation allows for the selective removal of contemporary thermoset resin based insulation systems to allow non-destructive penetration of insulation wall thicknesses to both examine critical areas and recover high performance metallic and non-metallic inserts for remanufacture; significantly reducing replacement costs and reactor downtime. The authors' analysis describes how the availability of engineering data from the selective and non-destructive removal of insulation materials will aid in the evaluation of original manufacture, materials and procedures; enabling redesign to enhance subsequent on line performance. They also discuss why the ability to recover coil and core assemblies for remanufacture will have a major economic impact on reactor management costs

Waste heat recovery system including a mechanism for collection, detection and removal of non-condensable gas

Science.gov (United States)

Ernst, Timothy C.; Zigan, James A.

2017-06-20

The disclosure describes a non-condensable gas collection, detection, and removal system for a WHR system that helps to maintain cycle efficiency of the WHR system across the life of an engine system associated with the WHR system. A storage volume is configured to collect non-condensable gas received from the working fluid circuit, and a release valve is configured to selectively release non-condensable gas contained within the storage volume.

Unavailability of the residual system heat removal of Angra 1 by Bayesian networks considering dependent failures

International Nuclear Information System (INIS)

Gomes, Many R.S.; Melo, Paulo F.F.F. e

2015-01-01

This work models by Bayesian networks the residual heat removal system (SRCR) of Angra I nuclear power plant, using fault tree mapping for systematically identifying all possible modes of occurrence caused by a large loss of coolant accident (large LOCA). The focus is on dependent events, such as the bridge system structure of the residual heat removal system and the occurrence of common-cause failures. We used the Netica™ tool kit, Norsys Software Corporation and Python 2.7.5 for modeling Bayesian networks and Microsoft Excel for modeling fault trees. Working with dependent events using Bayesian networks is similar to the solutions proposed by other models, beyond simple understanding and ease of application and modification throughout the analysis. The results obtained for the unavailability of the system were satisfactory, showing that in most cases the system will be available to mitigate the effects of an accident as described above. (author)

Unavailability of the residual system heat removal of Angra 1 by Bayesian networks considering dependent failures

Energy Technology Data Exchange (ETDEWEB)

Gomes, Many R.S.; Melo, Paulo F.F.F. e, E-mail: mgomes@con.ufrj.br, E-mail: frutuoso@nuclear.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Programa de Pos-Graduacao em Engenharia Nuclear

2015-07-01

This work models by Bayesian networks the residual heat removal system (SRCR) of Angra I nuclear power plant, using fault tree mapping for systematically identifying all possible modes of occurrence caused by a large loss of coolant accident (large LOCA). The focus is on dependent events, such as the bridge system structure of the residual heat removal system and the occurrence of common-cause failures. We used the Netica™ tool kit, Norsys Software Corporation and Python 2.7.5 for modeling Bayesian networks and Microsoft Excel for modeling fault trees. Working with dependent events using Bayesian networks is similar to the solutions proposed by other models, beyond simple understanding and ease of application and modification throughout the analysis. The results obtained for the unavailability of the system were satisfactory, showing that in most cases the system will be available to mitigate the effects of an accident as described above. (author)

Characterization and removal of specific organic constituents in an UASB-trickling-filter system treating domestic wastewater.

Science.gov (United States)

Pontes, Patrícia Procópio; Chernicharo, Carlos Augusto de Lemos

2011-01-01

This paper presents the characterization of specific organic constituents (carbohydrates, proteins and lipids) in raw sewage and in the anaerobic and aerobic effluents of a demo-scale (500 inhabitants) UASB- trickling-filter system. The evaluation of such parameters was carried out for two operating conditions, either without sludge recirculation (experiment I) from the trickling filter to the UASB reactor or with sludge recirculation (experiment II), for sludge thickening and stabilization, in the anaerobic reactor. The results showed that the contribution of acetic acid, carbohydrates, proteins and lipids amounted for approximately 70% of the total COD fed to the UASB during experiment I, whereas during experiment II these constituents amounted for only around 40% of the total COD. Although very high BOD and COD overall removal efficiencies were observed for the treatment system (around 90% and 80%, respectively), it was possible to infer that these efficiencies were mainly related to the removal of carbohydrates and lipids (around 80% removal), and of other non-identified constituents. The removal of proteins was much lower (around 50% removal), and the relative contribution of proteins to the total COD increased along the treatment course, being responsible for most of the residual COD of the treatment units. In the present system configuration, the UASB reactor played a major role in the removal of carbohydrates, whereas the trickling filter was very effective in the removal of lipids. The return of aerobic sludge for thickening and stabilization in the UASB reactor did not affect its performance.

Biological removal of the xenobiotic trichloroethylene (TCE) through cometabolism in nitrifying systems.

Science.gov (United States)

Kocamemi, B Alpaslan; Ceçen, F

2010-01-01

In the present study, cometabolic TCE degradation was evaluated using NH(4)-N as the growth-substrate. At initial TCE concentrations up to 845 microg/L, TCE degradation followed first-order kinetics. The increase in ammonium utilization rate favored the degradation of TCE. This ensured that biological transformation of TCE in nitrifying systems is accomplished through a cometabolic pathway by the catalysis of non-specific ammonia oxygenase enzyme of nitrifiers. The transformation yield (T(y)) of TCE, the amount of TCE degraded per unit mass of NH(4)-N, strongly depended on the initial NH(4)-N and TCE concentrations. In order to allow a rough estimation of TCE removal and nitrification at different influent TCE and NH(4)-N concentrations, a linear relationship was developed between 1/T(y) and the initial NH(4)-N/TCE ratio. The estimated T(y) values lead to the conclusion that nitrifying systems are promising candidates for biological removal of TCE through cometabolism.

Relationship between removable prosthesis and some systemics disorders

Directory of Open Access Journals (Sweden)

Pierre Le Bars

2015-01-01

Full Text Available This article reviews the dental literature concerning the potential impact of the removable prosthesis (RP on the health status of patients with certain systemic diseases. Literature was surveyed using Medline/PubMed database resources, as well as a manual search, up to 2015 to identify appropriate articles that addressed the aim of this review. The research used keywords about associations between RP and six pathologies: Human immunodeficiency virus infection, diabetes mellitus, pulmonary diseases, gastric-Helicobacter pylori, cancer, and cardiovascular diseases. Analysis of literature showed that in patients with dentures having one or more of the six general conditions listed, Candida albicans organism is more frequently found in the oral flora compared to healthy denture wearer. Although causality has not been established and pending further research on this topic, the hygienic practices necessary to minimize the risk of numerous pathologies should be strengthened in the case of these patients, all the more in the presence of physical or psychological disability. The relationship between the general diseases and increasing of oral candidiasis denture patients is not explained. Therefore, attention to oral hygiene and professional care for removing C. albicans may be beneficial in these medically compromised patients.

Relationship between removable prosthesis and some systemics disorders.

Science.gov (United States)

Le Bars, Pierre; Kouadio, Alain Ayepa; N'goran, Justin Koffi; Badran, Zahi; Soueidan, Assem

2015-01-01

This article reviews the dental literature concerning the potential impact of the removable prosthesis (RP) on the health status of patients with certain systemic diseases. Literature was surveyed using Medline/PubMed database resources, as well as a manual search, up to 2015 to identify appropriate articles that addressed the aim of this review. The research used keywords about associations between RP and six pathologies: Human immunodeficiency virus infection, diabetes mellitus, pulmonary diseases, gastric-Helicobacter pylori, cancer, and cardiovascular diseases. Analysis of literature showed that in patients with dentures having one or more of the six general conditions listed, Candida albicans organism is more frequently found in the oral flora compared to healthy denture wearer. Although causality has not been established and pending further research on this topic, the hygienic practices necessary to minimize the risk of numerous pathologies should be strengthened in the case of these patients, all the more in the presence of physical or psychological disability. The relationship between the general diseases and increasing of oral candidiasis denture patients is not explained. Therefore, attention to oral hygiene and professional care for removing C. albicans may be beneficial in these medically compromised patients.

Assessing the removal of organic micropollutants by a novel baffled osmotic membrane bioreactor-microfiltration hybrid system

KAUST Repository

Pathak, Nirenkumar; Li, Sheng; Kim, Youngjin; Chekli, Laura; Phuntsho, Sherub; Jang, Am; Ghaffour, NorEddine; Leiknes, TorOve; Shon, Ho Kyong

2018-01-01

A novel approach was employed to study removal of organic micropollutants (OMPs) in a baffled osmotic membrane bioreactor-microfiltration (OMBR-MF) hybrid system under oxic–anoxic conditions. The performance of OMBR-MF system was examined employing three different draw solutes (DS), and three model OMPs. The highest forward osmosis (FO) membrane rejection was attained with atenolol (100 %) due to its higher molar mass and positive charge. With inorganic DS caffeine (94-100 %) revealed highest removal followed by atenolol (89-96 %) and atrazine (16-40 %) respectively. All three OMPs exhibited higher removal with organic DS as compared to inorganic DS. Significant anoxic removal was observed for atrazine under very different redox conditions with extended anoxic cycle time. This can be linked with possible development of different microbial consortia responsible for diverse enzymes secretion. Overall, the OMBR-MF process showed effective removal of total organic carbon (98%) and nutrients (phosphate 97% and total nitrogen 85%), respectively.

Assessing the removal of organic micropollutants by a novel baffled osmotic membrane bioreactor-microfiltration hybrid system

KAUST Repository

Pathak, Nirenkumar

2018-04-14

A novel approach was employed to study removal of organic micropollutants (OMPs) in a baffled osmotic membrane bioreactor-microfiltration (OMBR-MF) hybrid system under oxic–anoxic conditions. The performance of OMBR-MF system was examined employing three different draw solutes (DS), and three model OMPs. The highest forward osmosis (FO) membrane rejection was attained with atenolol (100 %) due to its higher molar mass and positive charge. With inorganic DS caffeine (94-100 %) revealed highest removal followed by atenolol (89-96 %) and atrazine (16-40 %) respectively. All three OMPs exhibited higher removal with organic DS as compared to inorganic DS. Significant anoxic removal was observed for atrazine under very different redox conditions with extended anoxic cycle time. This can be linked with possible development of different microbial consortia responsible for diverse enzymes secretion. Overall, the OMBR-MF process showed effective removal of total organic carbon (98%) and nutrients (phosphate 97% and total nitrogen 85%), respectively.

Analysis and testing of W-DHR system for decay heat removal in the lead-cooled ELSY reactor

International Nuclear Information System (INIS)

Bandini, Giacomino; Meloni, Paride; Polidori, Massimiliano; Gaggini, Piero; Labanti, Valerio; Tarantino, Mariano; Cinotti, Luciano; Presciuttini, Leonardo

2009-01-01

An innovative LFR system that complies with GEN IV goals is under design in the frame of ELSY European project. ELSY is a lead-cooled pool-type reactor of about 1500 MW thermal power which normally relies on the secondary system for decay heat removal. Since the secondary system is not safety-grade and must be fully depressurized in case of detection of a steam generator tube rupture, an independent and much reliable decay heat removal (DHR) system is foreseen on the primary side. Owing to the limited capability of the Reactor Vessel Air Cooling System (RVACS) in this large power reactor, additional safety-grade loops equipped with coolers immersed in the primary coolant are necessary for an efficient removal of decay heat. Some of these loops (W-DHR) are of innovative design and may operate with water at atmospheric pressure. In the frame of the ICE program to be performed on the integral facility CIRCE at ENEA/Brasimone research centre within the EUROTRANS European project, integral circulation experiments with core heat transport and heat removal by steam generator will be conducted in a reactor pool-type configuration. Taking advantage from this experimental program, a mock-up of W-DHR heat exchanger will be tested in order to investigate its functional behavior for decay heat removal. Some pre-test calculations of W-DHR heat exchanger operation in CIRCE have been performed with the RELAP5 thermal-hydraulic code in order to support the heat exchanger design and test conduct. In this paper the experimental activity to be conducted in CIRCE and main results from W-DHR pre-test calculations are presented, along with a preliminary investigation of the W-DHR system efficiency in ELSY configuration. (author)

Analysis of a space debris laser removal system

Science.gov (United States)

Gjesvold, Evan; Straub, Jeremy

2017-05-01

As long as man ventures into space, he will leave behind debris, and as long as he ventures into space, this debris will pose a threat to him and his projects. Space debris must be located and decommissioned. Lasers may prove to be the ideal method, as they can operate at a distance from the debris, have a theoretically infinite supply of energy from the sun, and are a seemingly readily available technology. This paper explores the requirements and reasoning for such a laser debris removal method. A case is made for the negligibility of eliminating rotational velocity from certain systems, while a design schematic is also presented for the implementation of a cube satellite proof of concept.

Thermal-hydraulic analysis of an innovative decay heat removal system for lead-cooled fast reactors

International Nuclear Information System (INIS)

Giannetti, Fabio; Vitale Di Maio, Damiano; Naviglio, Antonio; Caruso, Gianfranco

2016-01-01

Highlights: • LOOP thermal-hydraulic transient analysis for lead-cooled fast reactors. • Passive decay heat removal system concept to avoid lead freezing. • Solution developed for the diversification of the decay heat removal functions. • RELAP5 vs. RELAP5-3D comparison for lead applications. - Abstract: Improvement of safety requirements in GEN IV reactors needs more reliable safety systems, among which the decay heat removal system (DHR) is one of the most important. Complying with the diversification criteria and based on pure passive and very reliable components, an additional DHR for the ALFRED reactor (Advanced Lead Fast Reactor European Demonstrator) has been proposed and its thermal-hydraulic performances are analyzed. It consists in a coupling of two innovative subsystems: the radiative-based direct heat exchanger (DHX), and the pool heat exchanger (PHX). Preliminary thermal-hydraulic analyses, by using RELAP5 and RELAP5-3D© computer programs, have been carried out showing that the whole system can safely operate, in natural circulation, for a long term. Sensitivity analyses for: the emissivity of the DHX surfaces, the PHX water heat transfer coefficient (HTC) and the lead HTC have been carried out. In addition, the effects of the density variation uncertainty on the results has been analyzed and compared. It allowed to assess the feasibility of the system and to evaluate the acceptable range of the studied parameters. A comparison of the results obtained with RELAP5 and RELAP5-3D© has been carried out and the analysis of the differences of the two codes for lead is presented. The features of the innovative DHR allow to match the decay heat removal performance with the trend of the reactor decay heat power after shutdown, minimizing at the same time the risk of lead freezing. This system, proposed for the diversification of the DHR in the LFRs, could be applicable in the other pool-type liquid metal fast reactors.

Thermal-hydraulic analysis of an innovative decay heat removal system for lead-cooled fast reactors

Energy Technology Data Exchange (ETDEWEB)

Giannetti, Fabio; Vitale Di Maio, Damiano; Naviglio, Antonio; Caruso, Gianfranco, E-mail: gianfranco.caruso@uniroma1.it

2016-08-15

Highlights: • LOOP thermal-hydraulic transient analysis for lead-cooled fast reactors. • Passive decay heat removal system concept to avoid lead freezing. • Solution developed for the diversification of the decay heat removal functions. • RELAP5 vs. RELAP5-3D comparison for lead applications. - Abstract: Improvement of safety requirements in GEN IV reactors needs more reliable safety systems, among which the decay heat removal system (DHR) is one of the most important. Complying with the diversification criteria and based on pure passive and very reliable components, an additional DHR for the ALFRED reactor (Advanced Lead Fast Reactor European Demonstrator) has been proposed and its thermal-hydraulic performances are analyzed. It consists in a coupling of two innovative subsystems: the radiative-based direct heat exchanger (DHX), and the pool heat exchanger (PHX). Preliminary thermal-hydraulic analyses, by using RELAP5 and RELAP5-3D© computer programs, have been carried out showing that the whole system can safely operate, in natural circulation, for a long term. Sensitivity analyses for: the emissivity of the DHX surfaces, the PHX water heat transfer coefficient (HTC) and the lead HTC have been carried out. In addition, the effects of the density variation uncertainty on the results has been analyzed and compared. It allowed to assess the feasibility of the system and to evaluate the acceptable range of the studied parameters. A comparison of the results obtained with RELAP5 and RELAP5-3D© has been carried out and the analysis of the differences of the two codes for lead is presented. The features of the innovative DHR allow to match the decay heat removal performance with the trend of the reactor decay heat power after shutdown, minimizing at the same time the risk of lead freezing. This system, proposed for the diversification of the DHR in the LFRs, could be applicable in the other pool-type liquid metal fast reactors.

Comparison of hydraulics and particle removal efficiencies in a mixed cell raceway and Burrows pond rearing system

Science.gov (United States)

Moffitt, Christine M.

2016-01-01

We compared the hydrodynamics of replicate experimental mixed cell and replicate standard Burrows pond rearing systems at the Dworshak National Fish Hatchery, ID, in an effort to identify methods for improved solids removal. We measured and compared the hydraulic residence time, particle removal efficiency, and measures of velocity using several tools. Computational fluid dynamics was used first to characterize hydraulics in the proposed retrofit that included removal of the traditional Burrows pond dividing wall and establishment of four counter rotating cells with appropriate drains and inlet water jets. Hydraulic residence time was subsequently established in the four full scale test tanks using measures of conductivity of a salt tracer introduced into the systems both with and without fish present. Vertical and horizontal velocities were also measured with acoustic Doppler velocimetry in transects across each of the rearing systems. Finally, we introduced ABS sinking beads that simulated fish solids then followed the kinetics of their removal via the drains to establish relative purge rates. The mixed cell raceway provided higher mean velocities and a more uniform velocity distribution than did the Burrows pond. Vectors revealed well-defined, counter-rotating cells in the mixed cell raceway, and were likely contributing factors in achieving a relatively high particle removal efficiency-88.6% versus 8.0% during the test period. We speculate retrofits of rearing ponds to mixed cell systems will improve both the rearing environments for the fish and solids removal, improving the efficiency and bio-security of fish culture. We recommend further testing in hatchery production trials to evaluate fish physiology and growth.

Investigation of characteristics of passive heat removal system based on the assembled heat transfer tube

Energy Technology Data Exchange (ETDEWEB)

Wu, Xiang Cheng; Yan, Changqi; Meng, Zhao Ming; Chen, Kailun; Song, Shao Chuang; Yang, Zong Hao; Yu, Jie [Fundamental Science on Nuclear Safety and Simulation Technology Laboratory, Harbin Engineering University, Harbin (China)

2016-12-15

To get an insight into the operating characteristics of the passive residual heat removal system of molten salt reactors, a two-phase natural circulation test facility was constructed. The system consists of a boiling loop absorbing the heat from the drain tank, a condensing loop consuming the heat, and a steam drum. A steady-state experiment was carried out, in which the thimble temperature ranged from 450 .deg. C to 700 .deg. C and the system pressure was controlled at levels below 150 kPa. When reaching a steady state, the system was operated under saturated conditions. Some important parameters, including heat power, system resistance, and water level in the steam drum and water tank were investigated. The experimental results showed that the natural circulation system is feasible in removing the decay heat, even though some fluctuations may occur in the operation. The uneven temperature distribution in the water tank may be inevitable because convection occurs on the outside of the condensing tube besides boiling with decreasing the decay power. The instabilities in the natural circulation loop are sensitive to heat flux and system resistance rather than the water level in the steam drum and water tank. RELAP5 code shows reasonable results compared with experimental data.

Investigation of Characteristics of Passive Heat Removal System Based on the Assembled Heat Transfer Tube

Directory of Open Access Journals (Sweden)

Xiangcheng Wu

2016-12-01

Full Text Available To get an insight into the operating characteristics of the passive residual heat removal system of molten salt reactors, a two-phase natural circulation test facility was constructed. The system consists of a boiling loop absorbing the heat from the drain tank, a condensing loop consuming the heat, and a steam drum. A steady-state experiment was carried out, in which the thimble temperature ranged from 450°C to 700°C and the system pressure was controlled at levels below 150 kPa. When reaching a steady state, the system was operated under saturated conditions. Some important parameters, including heat power, system resistance, and water level in the steam drum and water tank were investigated. The experimental results showed that the natural circulation system is feasible in removing the decay heat, even though some fluctuations may occur in the operation. The uneven temperature distribution in the water tank may be inevitable because convection occurs on the outside of the condensing tube besides boiling with decreasing the decay power. The instabilities in the natural circulation loop are sensitive to heat flux and system resistance rather than the water level in the steam drum and water tank. RELAP5 code shows reasonable results compared with experimental data.

Effectiveness of photocatalytic filter for removing volatile organic compounds in the heating, ventilation, and air conditioning system.

Science.gov (United States)

Yu, Kuo-Pin; Lee, Grace Whei-May; Huang, Wei-Ming; Wu, Chih-Cheng; Lou, Chia-ling; Yang, Shinhao

2006-05-01

Nowadays, the heating, ventilation, and air conditioning (HVAC) system has been an important facility for maintaining indoor air quality. However, the primary function of typical HVAC systems is to control the temperature and humidity of the supply air. Most indoor air pollutants, such as volatile organic compounds (VOCs), cannot be removed by typical HVAC systems. Thus, some air handling units for removing VOCs should be added in typical HVAC systems. Among all of the air cleaning techniques used to remove indoor VOCs, photocatalytic oxidation is an attractive alternative technique for indoor air purification and deodorization. The objective of this research is to investigate the VOC removal efficiency of the photocatalytic filter in a HVAC system. Toluene and formaldehyde were chosen as the target pollutants. The experiments were conducted in a stainless steel chamber equipped with a simplified HVAC system. A mechanical filter coated with Degussa P25 titania photocatalyst and two commercial photocatalytic filters were used as the photocatalytic filters in this simplified HVAC system. The total air change rates were controlled at 0.5, 0.75, 1, 1.25, and 1.5 hr(-1), and the relative humidity (RH) was controlled at 30%, 50%, and 70%. The ultraviolet lamp used was a 4-W, ultraviolet-C (central wavelength at 254 nm) strip light bulb. The first-order decay constant of toluene and formaldehyde found in this study ranged from 0.381 to 1.01 hr(-1) under different total air change rates, from 0.34 to 0.433 hr(-1) under different RH, and from 0.381 to 0.433 hr(-1) for different photocatalytic filters.

Application study of the heat pipe to the passive decay heat removal system of the modular HTR

International Nuclear Information System (INIS)

Ohashi, K.; Okamoto, F.; Hayakawa, H.; Hayashi, T.

2001-01-01

To investigate the applicability of the heat pipe to the decay hat removal (DHR) system of the modular HTRs, preliminary study of the Heat Pipe DHR System was performed. The results show that the Heat Pipe DHR System is applicable to the modular HTRs and its heat removal capability is sufficient. Especially by applying the variable conductance heat pipe, the possibility of a fully passive DHR system with lower heat loss during normal operation is suggested. The experiments to obtain the fundamental characteristics data of the variable conductance heat pipe were carried out. The experimental results show very clear features of self-control characteristics. The experimental results and the experimental analysis results are also shown. (author)

Pilot scale test of a produced water-treatment system for initial removal of organic compounds

Energy Technology Data Exchange (ETDEWEB)

Sullivan, Enid J [Los Alamos National Laboratory; Kwon, Soondong [UT-AUSTIN; Katz, Lynn [UT-AUSTIN; Kinney, Kerry [UT-AUSTIN

2008-01-01

A pilot-scale test to remove polar and non-polar organics from produced water was performed at a disposal facility in Farmington NM. We used surfactant-modified zeolite (SMZ) adsorbent beds and a membrane bioreactor (MBR) in combination to reduce the organic carbon content of produced water prior to reverse osmosis (RO). Reduction of total influent organic carbon (TOC) to 5 mg/L or less is desirable for efficient RO system operation. Most water disposed at the facility is from coal-bed gas production, with oil production waters intermixed. Up to 20 gal/d of produced water was cycled through two SMZ adsorbent units to remove volatile organic compounds (BTEX, acetone) and semivolatile organic compounds (e.g., napthalene). Output water from the SMZ units was sent to the MBR for removal of the organic acid component of TOC. Removal of inorganic (Mn and Fe oxide) particulates by the SMZ system was observed. The SMZ columns removed up to 40% of the influent TOC (600 mg/L). BTEX concentrations were reduced from the initial input of 70 mg/L to 5 mg/L by the SMZ and to an average of 2 mg/L after the MBR. Removal rates of acetate (input 120-170 mg/L) and TOC (input up to 45 mg/L) were up to 100% and 92%, respectively. The water pH rose from 8.5 to 8.8 following organic acid removal in the MBR; this relatively high pH was likely responsible for observed scaling of the MBR internal membrane. Additional laboratory studies showed the scaling can be reduced by metered addition of acid to reduce the pH. Significantly, organic removal in the MBR was accomplished with a very low biomass concentration of 1 g/L throughout the field trial. An earlier engineering evaluation shows produced water treatment by the SMZ/MBR/RO system would cost from $0.13 to $0.20 per bbl at up to 40 gpm. Current estimated disposal costs for produced water are $1.75 to $4.91 per bbl when transportation costs are included, with even higher rates in some regions. Our results suggest that treatment by an SMZ

Investigating the mechanism of clofibric acid removal in Fe(0)/H2O systems.

Science.gov (United States)

Ghauch, Antoine; Abou Assi, Hala; Tuqan, Almuthanna

2010-04-15

Since the introduction of iron wall technology, the inherent relationship between contaminant removal and iron corrosion has been mostly attributed to electron transfer from the metal body (direct reduction). This thermodynamically founded premise has failed to explain several experimental facts. Recently, a new concept considering adsorption and co-precipitation as fundamental contaminant removal mechanisms was introduced. This consistent concept has faced very skeptic views and necessarily needs experimental validation. The present work was the first independent attempt to validate the new concept using clofibric acid (CLO) as model compound. For this purpose, a powdered Fe(0) material (Fe(0)) was used in CLO removal experiments under various experimental conditions. Additional experiments were performed with plated Fe(0) (mFe(0): Fe(0)/Pd(0), Fe(0)/Ni(0)) to support the discussion of removal mechanism. Main investigated experimental variables included: abundance of O(2), abundance of iron corrosion products (ICPs) and shaking operations. Results corroborated the concept that quantitative contaminant removal in Fe(0)/H(2)O systems occurs within the oxide-film in the vicinity of Fe(0). Additionally, mixing type and shaking intensity significantly influenced the extent of CLO removal. More importantly, HPLC/MS revealed that the identity of reaction products depends on the extent of iron corrosion or the abundance of ICPs. The investigation of the CLO/Fe(0)/H(2)O system disproved the popular view that direct reduction mediates contaminant removal in the presence of Fe(0). 2009 Elsevier B.V. All rights reserved.

Dissolved nutrients and atrazine removal by column-scale monophasic and biphasic rain garden model systems.

Science.gov (United States)

Yang, Hanbae; McCoy, Edward L; Grewal, Parwinder S; Dick, Warren A

2010-08-01

Rain gardens are bioretention systems that have the potential to reduce peak runoff flow and improve water quality in a natural and aesthetically pleasing manner. We compared hydraulic performance and removal efficiencies of nutrients and atrazine in a monophasic rain garden design versus a biphasic design at a column-scale using simulated runoff. The biphasic rain garden was designed to increase retention time and removal efficiency of runoff pollutants by creating a sequence of water saturated to unsaturated conditions. We also evaluated the effect of C substrate availability on pollutant removal efficiency in the biphasic rain garden. Five simulated runoff events with various concentrations of runoff pollutants (i.e. nitrate, phosphate, and atrazine) were applied to the monophasic and biphasic rain gardens once every 5d. Hydraulic performance was consistent over the five simulated runoff events. Peak flow was reduced by approximately 56% for the monophasic design and 80% for the biphasic design. Both rain garden systems showed excellent removal efficiency of phosphate (89-100%) and atrazine (84-100%). However, significantly (prain garden (29-39%). Addition of C substrate in the form of glucose increased removal efficiency of nitrate significantly (prain gardens. (c) 2010 Elsevier Ltd. All rights reserved.

Multi-column adsorption systems with condenser for tritiated water vapor removal

International Nuclear Information System (INIS)

Kotoh, Kenji; Kudo, Kazuhiko

1996-01-01

Two types of multi-column adsorption system are proposed as the system for removal of tritiated moisture from tritium process gases or/and handling room atmospheres. The types are of recycle use of adsorption columns, and are composed of twin or triplet columns and one condenser which is used for collecting the adsorbed moisture from columns in desorption process. The systems utilize the dry gas from a working column as the purge gas for regenerating a saturated column and appropriate an active column for recovery of the tritiated moisture passing through the condenser. Each column hence needs the additional amount of adsorbent for collecting the moisture from the condenser. In the modeling and design of an adsorption column, it is primary to estimate the necessary amount of a candidate adsorbent for its packed-bed. The performance of the proposed systems is examined here by analyzing the dependence of the necessary amount of adsorbent for their columns on process operational conditions and adsorbent moisture-adsorption characteristics. The result shows that the necessary amount is sensitive to the types of adsorption isotherm, and suggests that these systems should employ adsorbents which exhibit the Langmuir-type isotherms. (author)

Micropollutants removal and health risk reduction in a water reclamation and ecological reuse system.

Science.gov (United States)

Ma, Xiaoyan Y; Li, Qiyuan; Wang, Xiaochang C; Wang, Yongkun; Wang, Donghong; Ngo, Huu Hao

2018-07-01

As reclaimed water use is increasing, its safety attracts growing attention, particularly with respect to the health risks associated with the wide range of micropollutants found in the reclaimed water. In this study, sophisticated analysis was conducted for water samples from a water reclamation and ecological reuse system where domestic wastewater was treated using an anaerobic-anoxic-oxic unit followed by a membrane bioreactor (A 2 O-MBR), and the reclaimed water was used for replenishing a landscape lake. A total of 58 organic micropollutants were detected in the system, consisting of 13 polycyclic aromatic hydrocarbons (PAHs), 16 phenols, 3 pesticides, and 26 pharmaceuticals and personal care products (PPCPs). After treatment by the A 2 O-MBR process, effective removal of pesticides and phenols was achieved, while when the reclaimed water entered the landscape lake, PPCPs were further removed. From the physicochemical properties of micropollutants, it could be inferred that phenols and dichlorphos (the only pesticide with considerable concentration in the influent) would have been mainly removed by biodegradation and/or volatilization in the biological treatment process. Additionally, it is probable that sludge adsorption also contributed to the removal of dichlorphos. For the predominant PPCP removal in the landscape lake, various actions, such as adsorption, biodegradation, photolysis, and ecologically mediated processes (via aquatic plants and animals), would have played significant roles. However, according to their logK oc , logK ow and logD (pH = 8) values, it could be concluded that adsorption by suspended solids might be an important action. Although carcinogenic and non-carcinogenic risks associated with all the detected micropollutants were at negligible levels, the hazard quotients (HQs) of PPCPs accounted for 92.03%-97.23% of the HQ Total . With the significant removal of PPCPs through the ecological processes in the landscape lake, the safety

Study of metal removal by square Wetland System with Eleocharis SP. using SR-XRF

International Nuclear Information System (INIS)

Avelino Neto, Sebastiao; Moreira, Silvana

2007-01-01

The pollution of the water resources for metals, results of different economic activities. The objective of the present study was to use the SR-TXRF technique to evaluate the performance of Wetland system cultivated with Eleocharis sp. installed at FEAGRI-UNICAMP, in the metal removal. The metals analyzed were Cr, Mn, Fe, Zn and Pb. Samples of the wastewater in the exit, Eleocharis sp. leaf and medium boulder were collected during 20 weeks consecutively. The system was operated with different outflows and hydraulic detention times (HDT) as: 600 L.day -1 (HDT 2 days), 400 L.day-1 (HDT 3 days), 300 L.day -1 (HDT 4 days) and 200 L.day -1 (HDT 6 days). The main source of metal removal was medium boulder with efficiency varying 30.1% for Cr and 98.9% for Pb, independent of the hydraulic detention time (HDT) used. The efficiency of the wetland in the Cr removal varied between 39.6 and 98.7%, and for Mn was higher than 81.6%. For Fe the performance was higher than 70.6% and for Cu the efficiency varied between 88.4 and 99.7 %, while for Pb the variation was 67.5 to 98.4 %. The wetland system with Eleocharis sp were in agreement with CONAMA legislation concern to Fe, Cu and Zn removal and for HDT of 2, 3, 4 and 6 days (HDT), moreover for Mn was necessary 4 and 6 days (HDT) and for Cr and Pb 6 days (HDT). (author)

Study of metal removal by square Wetland System with Eleocharis SP. using SR-XRF

Energy Technology Data Exchange (ETDEWEB)

Avelino Neto, Sebastiao; Moreira, Silvana [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo]. E-mails: savneto@bol.com.br; silvana@fec.unicamp.br

2007-07-01

The pollution of the water resources for metals, results of different economic activities. The objective of the present study was to use the SR-TXRF technique to evaluate the performance of Wetland system cultivated with Eleocharis sp. installed at FEAGRI-UNICAMP, in the metal removal. The metals analyzed were Cr, Mn, Fe, Zn and Pb. Samples of the wastewater in the exit, Eleocharis sp. leaf and medium boulder were collected during 20 weeks consecutively. The system was operated with different outflows and hydraulic detention times (HDT) as: 600 L.day{sup -1} (HDT 2 days), 400 L.day-1 (HDT 3 days), 300 L.day{sup -1} (HDT 4 days) and 200 L.day{sup -1} (HDT 6 days). The main source of metal removal was medium boulder with efficiency varying 30.1% for Cr and 98.9% for Pb, independent of the hydraulic detention time (HDT) used. The efficiency of the wetland in the Cr removal varied between 39.6 and 98.7%, and for Mn was higher than 81.6%. For Fe the performance was higher than 70.6% and for Cu the efficiency varied between 88.4 and 99.7 %, while for Pb the variation was 67.5 to 98.4 %. The wetland system with Eleocharis sp were in agreement with CONAMA legislation concern to Fe, Cu and Zn removal and for HDT of 2, 3, 4 and 6 days (HDT), moreover for Mn was necessary 4 and 6 days (HDT) and for Cr and Pb 6 days (HDT). (author)

Design and modeling of an advanced marine machinery system including waste heat recovery and removal of sulphur oxides

DEFF Research Database (Denmark)

Frimann Nielsen, Rasmus; Haglind, Fredrik; Larsen, Ulrik

2014-01-01

the efficiency of machinery systems. The wet sulphuric acid process is an effective way of removing flue gas sulphur oxides from land-based coal-fired power plants. Moreover, organic Rankine cycles (ORC) are suitable for heat to power conversion for low temperature heat sources. This paper describes the design...... that an ORC placed after the conventional waste heat recovery system is able to extract the sulphuric acid from the exhaust gas, while at the same time increase the combined cycle thermal efficiency by 2.6%. The findings indicate that the technology has potential in marine applications regarding both energy...... and modeling of a highly efficient machinery system which includes the removal of exhaust gas sulphur oxides. The system consists of a two-stroke diesel engine, the wet sulphuric process for sulphur removal, a conventional steam Rankine cycle and an ORC. Results of numerical modeling efforts suggest...

Numerical modeling analysis of VOC removal processes in different aerobic vertical flow systems for groundwater remediation

NARCIS (Netherlands)

De Biase, C.; Carminati, A.; Oswald, S.E.; Thullner, M.

2013-01-01

Vertical flow systems filled with porous medium have been shown to efficiently remove volatile organic contaminants (VOCs) from contaminated groundwater. To apply this semi-natural remediation strategy it is however necessary to distinguish between removal due to biodegradation and due to volatile

Development of Carbon Dioxide Removal Systems for Advanced Exploration Systems 2014-2015

Science.gov (United States)

Knox, James C.; Coker, Robert; Huff, Timothy L.; Gatens, Robyn; Miller, Lee A.; Stanley, Christine

2015-01-01

A long-term goal for NASA is to enable crewed missions to Mars: first to the vicinity of Mars, and then to the Mars surface. These missions present new challenges for all aspects of spacecraft design in comparison with the International Space Station, as resupply is unavailable in the transit phase, and early return is not possible. Additionally, mass, power, and volume must be minimized for all phases to reduce propulsion needs. Mass reduction is particularly crucial for Mars surface landing and liftoff due to the challenges inherent in these operations for even much smaller payloads. In this paper we describe current and planned developments in the area of carbon dioxide removal to support future crewed Mars missions. Activities are also described that apply to both the resolution of anomalies observed in the ISS CDRA and the design of life support systems for future missions.

Development of Carbon Dioxide Removal Systems for Advanced Exploration Systems 2015-2016

Science.gov (United States)

Knox, James; Coker, Robert; Huff, Tim; Miller, Lee

2016-01-01

A long-term goal for NASA is to enable crewed missions to Mars: first to the vicinity of Mars, and then to the Mars surface. These missions present new challenges for all aspects of spacecraft design in comparison with the International Space Station, as resupply is unavailable in the transit phase, and early return is not possible. Additionally, mass, power, and volume must be minimized for all phases to reduce propulsion needs. Mass reduction is particularly crucial for Mars surface landing and liftoff due to the challenges inherent in these operations for even much smaller payloads. In this paper we describe current and planned developments in the area of carbon dioxide removal to support future crewed Mars missions. Activities are also described that apply to both the resolution of anomalies observed in the ISS CDRA and the design of life support systems for future missions.

ETV REPORT: REMOVAL OF ARSENIC IN DRINKING WATER - PALL CORPORATION MICROZA. MICROFILTRATION SYSTEM

Science.gov (United States)

Verification testing of the Pall Corporation Microza. Microfiltration System for arsenic removal was conducted at the Oakland County Drain Commissioner (OCDC) Plum Creek Development well station located in Oakland County, Michigan from August 19 through October 8, 2004. The sourc...

Highly efficient removal of chromium(VI) by Fe/Ni bimetallic nanoparticles in an ultrasound-assisted system.

Science.gov (United States)

Zhou, Xiaobin; Jing, Guohua; Lv, Bihong; Zhou, Zuoming; Zhu, Runliang

2016-10-01

Highly active Fe/Ni bimetallic nanocomposites were prepared by using the liquid-phase reduction method, and they were proven to be effective for Cr(VI) removal coupled with US irradiation. The US-assisted Fe/Ni bimetallic system could maintain a good performance for Cr(VI) removal at a wide pH range of 3-9. Based on the characterization of the Fe/Ni nanoparticles before and after reaction, the high efficiency of the mixed system could attribute to the synergistic effects of the catalysis of Ni(0) and US cavitation. Ni(0) could facilitate the Cr(VI) reduction through electron transfer and catalytic hydrogenation. Meanwhile, US could fluidize the Fe/Ni nanoparticles to increase the actual reactive surface area and clean off the co-precipitated Fe(III)-Cr(III) hydroxides to maintain the active sites on the surface of the Fe/Ni nanoparticles. Thus, compared with shaking, the US-assisted Fe/Ni system was more efficient on Cr(VI) removal, which achieved 94.7% removal efficiency of Cr(VI) within 10 min. The pseudo-first-order rate constant (kobs) in US-assisted Fe/Ni system (0.5075 min(-1)) was over 5 times higher than that under shaking (0.0972 min(-1)). Moreover, the Fe/Ni nanoparticles still have a good performance under US irradiation after 26 days aging as well as regeneration. Copyright © 2016 Elsevier Ltd. All rights reserved.

Removal of Airborne Contaminants from a Surface Tank by a Push-Pull System

DEFF Research Database (Denmark)

Heiselberg, Per; Topp, Claus

Open surface tanks are used in many industrial processes, and local exhaust systems are often designed to capture and remove toxic fumes diffused from materials in the tanks prior to their escape into the workplace environment. The push-pull system seems to be the most efficient local exhaust...... system, but proper design is required to ensure health and safety of the workers and, furthermore, it is very desirable from an energy conservation point of view to determine an optimum and -an efficient design of push-pull hoods which can exhaust all contaminants with a minimum quantity of volume flow....... The paper describes and discusses different design methods and compares designed values with results from a measurement series of push-pull system efficiency....

A study on the silica removal in primary system using the membrane process

International Nuclear Information System (INIS)

Kim, Bong Jin; Lee, Sang Jin; Yang, Ho Yeon; Kim, Kyung Duk; Jung, Hee Chul; Jo, Hang Rae

2005-01-01

Silica in primary system combines with an alkali grammatical particle metal and forms the zeolite layer which is hindering the heat transfer on the surface of the cladding. Zeolite layer becomes the cause of the damage in this way. The problems of the NPP's primary system have been issued steadily by EPRI. Through a series of experiments of the laboratory scale, we confirmed the applicability of NF membrane for silica removal, as silica rejection rate of NF membrane is about 60 ∼ 70% and boron rejection rate is about 10 ∼ 20%. We accomplished a site experiment about four NF membranes manufactured by FilmTec and Osmonics Inc. In experiment using 400L of SFP water, when operation pressure is 10kg f /cm 2 , we confirmed that the silica rejection rate of NF90-2540 manufactured by FilmTec Inc. is about 98%, boron rejection rate is about 43%. The silica rejection rate of NF270-2540 is about 38%, boron rejection rate is about 3.5%. Afterward, through additional experiments, such as long term characteristic experiments, we are going to design a optimum NF membrane system for silica removal

A study on the silica removal in primary system using the membrane process

Energy Technology Data Exchange (ETDEWEB)

Kim, Bong Jin; Lee, Sang Jin; Yang, Ho Yeon; Kim, Kyung Duk [Korea Hydro and Nuclear Power Co., LTD., Taejeon (Korea, Republic of); Jung, Hee Chul; Jo, Hang Rae [Korea Hydro and Nuclear Power Co., LTD., Uljin (Korea, Republic of)

2005-06-15

Silica in primary system combines with an alkali grammatical particle metal and forms the zeolite layer which is hindering the heat transfer on the surface of the cladding. Zeolite layer becomes the cause of the damage in this way. The problems of the NPP's primary system have been issued steadily by EPRI. Through a series of experiments of the laboratory scale, we confirmed the applicability of NF membrane for silica removal, as silica rejection rate of NF membrane is about 60 {approx} 70% and boron rejection rate is about 10 {approx} 20%. We accomplished a site experiment about four NF membranes manufactured by FilmTec and Osmonics Inc. In experiment using 400L of SFP water, when operation pressure is 10kg{sub f}/cm{sup 2}, we confirmed that the silica rejection rate of NF90-2540 manufactured by FilmTec Inc. is about 98%, boron rejection rate is about 43%. The silica rejection rate of NF270-2540 is about 38%, boron rejection rate is about 3.5%. Afterward, through additional experiments, such as long term characteristic experiments, we are going to design a optimum NF membrane system for silica removal.

Application of bacteriophages to selectively remove Pseudomonas aeruginosa in water and wastewater filtration systems.

Science.gov (United States)

Zhang, Yanyan; Hunt, Heather K; Hu, Zhiqiang

2013-09-01

Water and wastewater filtration systems often house pathogenic bacteria, which must be removed to ensure clean, safe water. Here, we determine the persistence of the model bacterium Pseudomonas aeruginosa in two types of filtration systems, and use P. aeruginosa bacteriophages to determine their ability to selectively remove P. aeruginosa. These systems used beds of either anthracite or granular activated carbon (GAC), which were operated at an empty bed contact time (EBCT) of 45 min. The clean bed filtration systems were loaded with an instantaneous dose of P. aeruginosa at a total cell number of 2.3 (± 0.1 [standard deviation]) × 10(7) cells. An immediate dose of P. aeruginosa phages (1 mL of phage stock at the concentration of 2.7 × 10(7) PFU (Plaque Forming Units)/mL) resulted in a reduction of 50% (± 9%) and >99.9% in the effluent P. aeruginosa concentrations in the clean anthracite and GAC filters, respectively. To further evaluate the effects of P. aeruginosa phages, synthetic stormwater was run through anthracite and GAC biofilters where mixed-culture biofilms were present. Eighty five days after an instantaneous dose of P. aeruginosa (2.3 × 10(7) cells per filter) on day 1, 7.5 (± 2.8) × 10(7) and 1.1 (± 0.5) × 10(7) P. aeruginosa cells/g filter media were detected in the top layer (close to the influent port) of the anthracite and GAC biofilters, respectively, demonstrating the growth and persistence of pathogenic bacteria in the biofilters. A subsequent 1-h dose of phages, at the concentration of 5.1 × 10(6) PFU/mL and flow rate of 1.6 mL/min, removed the P. aeruginosa inside the GAC biofilters and the anthracite biofilters by 70% (± 5%) and 56% (± 1%), respectively, with no P. aeruginosa detected in the effluent, while not affecting ammonia oxidation or the ammonia-oxidizing bacterial community inside the biofilters. These results suggest that phage treatment can selectively remove pathogenic bacteria with minimal impact on beneficial

Microbial community changes in biological phosphate-removal systems on altering sludge phosphorus content

NARCIS (Netherlands)

Liu, WT; Linning, KD; Nakamura, K; Mino, T; Matsuo, T; Forney, LJ

Biomarkers (respiratory quinones and cellular fatty acids) and denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA genes were used to characterize the microbial community structure of lab-scale enhanced biological phosphate-removal (EBPR) systems in response to altering sludge

A portable system for acquiring and removing motion artefact from ECG signals

Science.gov (United States)

Griffiths, A.; Das, A.; Fernandes, B.; Gaydecki, P.

2007-07-01

A novel electrocardiograph (ECG) signal acquisition and display system is under development. It is designed for patients ranging from the elderly to athletes. The signals are obtained from electrodes integrated into a vest, amplified, digitally processed and transmitted via Bluetooth to a PC with a Labview ® interface. Digital signal processing is performed to remove movement artefact and electromyographic (EMG) noise, which severely distorts signal morphology and complicates clinical diagnosis. Independent component analysis (ICA) is also used to improve the signal quality. The complete system will integrate the electronics into a single module which will be embedded in the vest.

A portable system for acquiring and removing motion artefact from ECG signals

Energy Technology Data Exchange (ETDEWEB)

Griffiths, A; Das, A; Fernandes, B; Gaydecki, P [School of Electrical and Electronic Engineering, University of Manchester, PO Box 88, Manchester M60 1QD (United Kingdom)

2007-07-15

A novel electrocardiograph (ECG) signal acquisition and display system is under development. It is designed for patients ranging from the elderly to athletes. The signals are obtained from electrodes integrated into a vest, amplified, digitally processed and transmitted via Bluetooth to a PC with a Labview (registered) interface. Digital signal processing is performed to remove movement artefact and electromyographic (EMG) noise, which severely distorts signal morphology and complicates clinical diagnosis. Independent component analysis (ICA) is also used to improve the signal quality. The complete system will integrate the electronics into a single module which will be embedded in the ves000.

Highly Efficient Closed-Loop CO2 Removal System for Deep-Space ECLSS, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — TDA Research Inc.(TDA) in collaboration with University of Puerto Rico ? Mayaguez (UPRM is proposing to develop a highly efficient CO2 removal system based on UPRM...

Design of passive decay heat removal system using thermosyphon for low temperature and low pressure pool type LWR

Energy Technology Data Exchange (ETDEWEB)

Moon, Jangsik; You, Byung Hyun; Jung, Yong Hun; Jeong, Yong Hoon [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2013-10-15

In seawater desalination process which doesn't need high temperature steam, the reactor has profitability. KAIST has be developing the new reactor design, AHR400, for only desalination. For maximizing safety, the reactor requires passive decay heat removal system. In many nuclear reactors, DHR system is loop form. The DHR system can be designed simple by applying conventional thermosyphon, which is fully passive device, shows high heat transfer performance and simple structure. DHR system utilizes conventional thermosyphon and its heat transfer characteristics are analyzed for AHR400. For maximizing safety of the reactor, passive decay heat removal system are prepared. Thermosyphon is useful device for DHR system of low pressure and low temperature pool type reactor. Thermosyphon is operated fully passive and has simple structure. Bundle of thermosyphon get the goal to prohibit boiling in reactor and high pressure in reactor vessel.

Gadolinium removal from the moderator system of TAPP - 3 using the three layer bed

International Nuclear Information System (INIS)

Tripathi, V.S.; Balaji, V.; Venkateswaran, G.; Dash, S.C.

2008-01-01

Nitric acid leaching from the weak base anion (WBA) exchanger had been evaluated and based on this a 5% mixture of nitric acid loaded weak base anion exchanger with fresh weak base anion exchanger (NLWBA) at the bottom of the ion exchange column has been devised to maintain an outlet pH in the range of 5.0 to 5.5 during Gd removal from the moderator system of TAPP - 3 and 4. A three layered bed had been constituted wherein strong acid cation (SAC) exchanger is placed as the top layer while a mixed bed of SAC and WBA or pure WBA is used as the middle layer and the 5% NLWBA was used as the bottom most layer. This bed configuration would result in an iso-pH regime in the moderator system during the Gd removal along with quantitative removal of Gd. Two three-layer bed columns were prepared at TAPS - 3 and 4 in July 07. The resin was loaded in batches and after preparing the column, the column was deuterated with heavy water (> 99.75 % w/w) at a steady flow rate of 280 ml/min. After achieving high-grade isotopic purity viz. > 99.75 % w/w., these columns were preserved for their use after SDS - 2 actuation in the plant. Biennial Shut Down (BSD) of Unit - 3 was taken on 04-05-08 by SDS-2 actuation resulting in 16.37 ppm Gd in the moderator system. Gd removal to the extent about 8 mg/kg as designed could be done on one three layer bed. The use of this bed has resulted in an iso-pH regime at the column inlet and outlet. Conductivity values observed in the system were within the specifications. The three layer bed of a configuration slightly modified from the one tested in this work is expected to improve the column efficiency to 100% from the presently observed 87% and 97% respectively for the IX-2 and IX-3. (author)

Evaluation of Phosphate and Nitrate Removal Capacity of Anodonta cygnea (Unionidae in Open and Closed Systems

Directory of Open Access Journals (Sweden)

Arash Javanshir

2008-06-01

Full Text Available Discharge of agricultural and industrial effluents into surface water resources cause water quality degradation. The swan mussel (Anodonta cygnea is one of the most important fresh water suspension feeders that can be used for the purpose of pollutant reduction. In order to evaluate the capability of A. cygnea in the reduction of nitrates and phosphates in municipal wastewater, several breeds & Rhyter culture medium were investigated. The results obtained from the open system showed that the growing fresh algae were capable of removing a considerable portion of the dissolved materials. The combined system of mussels and algae had an average nitrate removal efficiency of 76.3% and a phosphate removal efficiency of 75.3%. Based on our results, this breed of mussels may be recommended as a crucial organism in biological wastewater treatment.

Reliability evaluation of power supply and distribution for special heat removal systems in nuclear power stations

International Nuclear Information System (INIS)

Jazbec, D.

1982-01-01

An example of the power supply and distribution of a Special Emergency Heat Removal System (SEHR) shows how an engineering organization may, with the aid of the analytical method of min-cut sets optimize the system reliability. Herein are given the necessary simple calculation methods. (Auth.)

Long term operation of continuous-flow system with enhanced biological phosphorus removal granules at different COD loading.

Science.gov (United States)

Li, Dong; Lv, Yufeng; Zeng, Huiping; Zhang, Jie

2016-09-01

In this study, a continuous-flow system with enhanced biological phosphorus removal (EBPR) granules was operated at different COD concentrations (200, 300 and 400mgL(-)(1)) to investigate the effect of COD loading on this system. The results showed that when the COD concentration in influent was increased to 400mgL(-)(1), the anaerobic COD removal efficiency and total phosphorus removal efficiency reduced obviously and the settling ability of granules deteriorated due to the proliferation of filamentous bacteria. Moreover, high COD loading inhibited the EPS secretion and destroyed the stability of granules. Results of high-through pyrosequencing indicated that filamentous bacteria had a competitive advantage over polyphosphate-accumulating organisms (PAOs) at high COD loading. The performance of system, settling ability of granules and proportion of PAOs gradually recovered to the initial level after the COD concentration was reduced to 200mgL(-)(1) on day 81. Copyright © 2016 Elsevier Ltd. All rights reserved.

A design assessment of tritium removal systems for the mirror advanced reactor study

International Nuclear Information System (INIS)

Sood, S.K.; Kveton, O.K.

1983-01-01

This study investigates the available processes for removing tritium from light water, and selects the most appropriate process for recovering tritium from the various tritiated water streams identified in the Mirror Advanced Reactor Study (MARS). A simplified flowsheet is shown for the process and the main process parameters are identified. Previous experience is utilized to predict direct capital costs and power requirement for the Tritiated Water Removal Unit (TWRU). A number of possibilities are discussed for lowering the cost of the TWRU. An estimate is made of the direct capital cost for the Air Detritiation System that has already been selected as the reference design by MARS personnel. The leakage from the MARS coolant loop is estimated, based on the experience obtained with Ontario Hydro's coolant systems. Design targets are identified for tritium levels in the reactor hall atmosphere and in water and air emissions. Tritium levels are predicted for these and are assessed against the previously identified targets

Loss of residual heat removal system: Diablo Canyon, Unit 2, April 10, 1987

International Nuclear Information System (INIS)

1987-06-01

This report presents the findings of an NRC Augmented Inspection Team (AIT) investigation into the circumstances associated with the loss of residual heat removal (RHR) system capability for a period of approximately one and one-half hours at the Diablo Canyon, Unit 2 reactor facility on April 10, 1987. This event occurred while the Diablo Canyon, Unit 2, a pressurized water reactor, was shutdown with the reactor coolant system (RCS) water level drained to approximately mid-level of the hot leg piping. The reactor containment building equipment hatch was removed at the time of the event, and plant personnel were in the process of removing the primary side manways to gain access into the steam generator channel head areas. Thus, two fission product barriers were breached throughout the event. The RCS temperature increased from approximately 87 0 F to bulk boiling conditions without RCS temperature indication available to the plant operators. The RCS was subsequently pressurized to approximately 7 to 10 psig. The NRC AIT members concluded that the Diablo Canyon, Unit 2 plant was, at the time of the event, in a condition not previously analyzed by the NRC staff. The AIT findings from this event appear significant and generic to other pressurized water reactor facilities licensed by the NRC

The Use of Reactive Materials in Septic Systems for Pathogens and Nitrate Removal

Science.gov (United States)

Suhogusoff, A. V.; Hirata, R.; Aravena, R.; Stimson, J.; Robertson, W.

2009-05-01

The developing countries have an urgent need for cheap and efficient techniques for the improvement of sanitary conditions in areas without public water supply and sewerage system, especially in suburban regions or irregular occupation areas, where there is a great lack of social assistance. In this type of situations, the inhabitants use dug wells for water use and cesspits for disposal of sewage, which usually contaminates the groundwater with nitrate and microorganisms. As part of a study aiming to develop new sewage treatment systems in an irregular occupation area located at the District of Barragem, south region of the municipality of São Paulo (Brazil), a conventional cesspit (named as "Control") and an alternative septic system were constructed and monitored for a year. The design of the alternative septic system included a 1m thickness reactive barrier constituted by BOF (Budget Oxygen Furnace - a byproduct of the steel-making industry) for pathogens removal, then 1m sand package where the wastewater is oxidized and at the bottom the wastewater is in contact with a 0,5m thickness reactive barrier constituted by sawdust (carbon source), where redox conditions are very reducing and denitrification and even methanogenesis can take place. The chemical and biological data collected in the alternative septic system showed complete removal of the pathogens in the BOF barrier, then nitrification occurred between the BOF and the bottom of sand package. However denitrification in the sawdust barrier was incomplete because of the high pH caused by the BOF materials, which can reduced the number of denitrifiers bacteria present in the sawdust barrier. Isotope analyses that are been carried out in the residual nitrate will provided more information about the extent of the denitrification reaction in the alternative septic system. In case of the control cesspit, it was observed the occurrence of high concentration of ammonium, dissolved organic carbon, CO2, CH4 and low

Study on heat removal capability concrete cask system with horizontal orientation

International Nuclear Information System (INIS)

Nabemoto, Toyonobu; Sakai, Mikio; Fujiwara, Hiroaki; Sakaya, Tadatsugu

2002-01-01

In Japan, nuclear fuel cycle, has been promoted, so the recycle fuels formed at nuclear power stations are planned to be processed at reprocessing facilities in future. However, as forming quantities of the recycle fuels are more than reprocessing quantities of the facilities, it is needed to practice a facility (interim storage facility (ISF)) to temporarily store them among the recycle fuels will be reprocessed. The Ishikawajima-Harima Heavy Industries, Co., Ltd. has investigated on vault system and concrete cask system for dry storage system with excellent economical efficiency among various systems on ISFs. As the latter method has a number of actual results in U.S.A., its practice is progressed after some improvements suitable for Japan. When progressing this practice on the latter method on fiscal year 1999, at first, a concrete cask with actual size was experimentally produced, to confirm its productivity. On fiscal year 2000, aiming to establish heat removal evaluation at storage, a thermal load test simulated at the storage was carried out by using this trial product. Here was reported results obtained at a test simulated at repacking carried out on fiscal year 2001. (G.K.)

Optimization of high-rate TN removal in a novel constructed wetland integrated with microelectrolysis system treating high-strength digestate supernatant.

Science.gov (United States)

Guo, Luchen; He, Keli; Wu, Shubiao; Sun, Hao; Wang, Yanfei; Huang, Xu; Dong, Renjie

2016-08-01

The potential of high-rate TN removal in three aerated horizontal subsurface-flow constructed wetlands to treat high-strength anaerobic digestate supernatant was evaluated. Different strategies of intermittent aeration and effluent recirculation were applied to compare their effect on nitrogen depuration performance. Additional glucose supply and iron-activated carbon based post-treatment systems were established and examined, respectively, to further remove nitrate that accumulated in the effluents from aerated wetlands. The results showed that intermittent aeration (1 h on:1 h off) significantly improved nitrification with ammonium removal efficiency of 90% (18.1 g/(m(2)·d)), but limited TN removal efficiency (53%). Even though effluent recirculation (a ratio of 1:1) increased TN removal from 53% to 71%, the effluent nitrate concentration was still high. Additional glucose was used as a post-treatment option and further increased the TN removal to 82%; however, this implementation caused additional organic pollution. Furthermore, the iron-activated carbon system stimulated with a microelectrolysis process achieved greater than 85% effluent nitrate removal and resulted in 86% TN removal. Considering the high TN removal rate, aerated constructed wetlands integrated with a microelectrolysis-driven system show great potential for treating high-strength digestate supernatant. Copyright © 2016 Elsevier Ltd. All rights reserved.

Concept Design of a Gravity Core Cooling Tank as a Passive Residual Heat Removal System for a Research Reactor

International Nuclear Information System (INIS)

Lee, Kwonyeong; Chi, Daeyoung; Kim, Seong Hoon; Seo, Kyoungwoo; Yoon, Juhyeon

2014-01-01

A core downward flow is considered to use a plate type fuel because it is benefit to install the fuel in the core. If a flow inversion from a downward to upward flow in the core by a natural circulation is introduced within a high heat flux region of residual heat, the fuel fails instantly due to zero flow. Therefore, the core downward flow should be sufficiently maintained until the residual heat is in a low heat flux region. In a small power research reactor, inertia generated by a flywheel of the PCP can maintain a downward flow shortly and resolve the problem of a flow inversion. However, a high power research reactor more than 10 MW should have an additional method to have a longer downward flow until a low heat flux. Usually, other research reactors have selected an active residual heat removal system as a safety class. But, an active safety system is difficult to design and expensive to construct. A Gravity Core Cooling Tank (GCCT) beside the reactor pool with a Residual Heat Removal Pipe connecting two pools was developed and designed preliminarily as a passive residual heat removal system for an open-pool type research reactor. It is very simple to design and cheap to construct. Additionally, a non-safety, but active residual heat removal system is applied with the GCCT. It is a Pool Water Cooling and Purification System. It can improve the usability of the research reactor by removing the thermal waves, and purify the reactor pool, the Primary Cooling System, and the GCCT. Moreover, it can reduce the pool top radiation level

Improving the Effectiveness of a Nutrient Removal System Composed of Microalgae and Daphnia by an Artificial Illumination

Directory of Open Access Journals (Sweden)

In-Ho Chang

2014-03-01

Full Text Available For determining the effect of illumination on nutrient removal in an artificial food web (AFW system, we launched a pilot continuous-flow system. The system consisted of a storage basin, a phytoplankton growth chamber, and a zooplankton growth chamber. A 25,000 Lux AFW-light emitting diode (LED on system and an AFW-LED off system were separately operated for 10 days. In the AFW-LED on system, the maximum chlorophyll-a concentration of the phytoplankton chamber was four times higher than that of the AFW-LED off system. With artificial nighttime illumination, the microalgae became both smaller and more nutritious; the microalgae became high quality food for the zooplankton, Daphnia magna. Consequently, this zooplankton became more efficient at extracting nutrients and grew more densely than in the AFW-LED off system condition. In the LED-on condition, the amounts of total nitrogen (TN and total phosphorus (TP flowing into the system for 10 days were 84.7 g and 20.4 g, and the amounts flowing out were 19.5 g (23% and 4.0 g (20%, respectively. In contrast, in the LED-off condition, 83.8 g and 20.6 g of TN and TP flowed into the system while 38.8 g (46% and 6.8 g (33% flowed out, respectively. Artificial illumination significantly improves the removal rate of nutrients in an AFW system.

Effects of iron and calcium carbonate on contaminant removal efficiencies and microbial communities in integrated wastewater treatment systems.

Science.gov (United States)

Zhao, Zhimiao; Song, Xinshan; Zhang, Yinjiang; Zhao, Yufeng; Wang, Bodi; Wang, Yuhui

2017-12-01

In the paper, we explored the influences of different dosages of iron and calcium carbonate on contaminant removal efficiencies and microbial communities in algal ponds combined with constructed wetlands. After 1-year operation of treatment systems, based on the high-throughput pyrosequencing analysis of microbial communities, the optimal operating conditions were obtained as follows: the ACW10 system with Fe 3+ (5.6 mg L -1 ), iron powder (2.8 mg L -1 ), and CaCO 3 powder (0.2 mg L -1 ) in influent as the adjusting agents, initial phosphorus source (PO 4 3- ) in influent, the ratio of nitrogen to phosphorus (N/P) of 30 in influent, and hydraulic retention time (HRT) of 1 day. Total nitrogen (TN) removal efficiency and total phosphorus (TP) removal efficiency were improved significantly. The hydrolysis of CaCO 3 promoted the physicochemical precipitation in contaminant removal. Meanwhile, Fe 3+ and iron powder produced Fe 2+ , which improved contaminant removal. Iron ion improved the diversity, distribution, and metabolic functions of microbial communities in integrated treatment systems. In the treatment ACW10, the dominant phylum in the microbial community was PLANCTOMYCETES, which positively promoted nitrogen removal. After 5 consecutive treatments in ACW10, contaminant removal efficiencies for TN and TP respectively reached 80.6% and 57.3% and total iron concentration in effluent was 0.042 mg L -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

The application of polyelectrolytes to improve liquid radwaste treatment system radionuclide removal efficiency

International Nuclear Information System (INIS)

Homyk, W.A.; Spall, M.J.; Vance, J.N.

1990-01-01

At nuclear plants, miscellaneous waste water treated in the liquid radwaste processing system contains a significant fraction of suspended particulate materials ranging in size from a few microns down to the submicron region. The fewer particles that typically exist as colloids are generally negatively charged by virtue of inorganic and organic anions absorbed onto the particle surfaces. Because many of the radionuclides exist as colloids and resist agglomeration and settling they are not easily removed by mechanical filtration or ion exchange processes. The colloidal materials will easily pass through most filters with conventional pore size ratings and through most ion exchange media. This leads to poor decontamination Factors (dFs) and higher radionuclide releases to the environment. A laboratory-scale testing program was conducted at Indian Point Unit No. 2 to determine the effectiveness of the use of organic polyelectrolytes to destabilize colloidal suspensions in liquid radwaste. Destabilizing colloidal suspensions will improve the removal efficiencies of the suspended material by typical filtration and ion exchange processes. The increased removal efficiencies will provide increased dFs in the liquid radwaste treatment system. The testing focused on identifying the specific organic polyelectrolytes and the associated dosages which would be effective in destabilizing the colloidal suspensions on actual waste water samples. The testing also examined the filtration characteristics of the water source to determine filter parameters such as: body feed material, body feed dosages, specific flow rates, etc., which would provide the basis for the design of filtration systems for these applications. The testing effort and the major conclusions from this investigation are given. 4 refs., 8 figs., 2 tabs

Microbial metabolism and activity in terms of nitrate removal in bioelectrochemical systems

International Nuclear Information System (INIS)

Huang, Baocheng; Feng, Huajun; Ding, Yangcheng; Zheng, Xin; Wang, Meizhen; Li, Na; Shen, Dongsheng; Zhang, Haiyang

2013-01-01

Highlights: • Influence of current on biofilm formation in BES was investigated. • Biofilm formation activity supplying with organic differed with inorganic. • Discussed the influence of signaling molecule and EPS on biofilm formation. -- Abstract: Bioelectrochemical systems (BESs) are a promising technology for generating energy while treating wastewater. By utilizing the electron transfer between the anode and cathode, nitrate can be effectively removed from the BES. Our previous studies show that the carbon source and C/N ratio influences nitrate removal performance. The study presented here investigates how biofilm formation, nitrate removal and signaling molecule release are related in the BESs fed with glucose, starch and HCO 3 − . The results indicate that increasing the current can benefit signaling molecule (DSF) release and extracellular polymeric substances (EPS) excretion, which improves biofilm formation. However, when the current exceeds the optimum value, the influence becomes adverse. Nitrate removal was also improved with increased current, though different carbon sources showed different trends. The highest nitrate removal efficiency of 1.23 ± 0.27, 1.38 ± 0.09, 1.80 ± 0.02 mmol L −1 d −1 for the BESs fed with glucose, starch and HCO 3 − were achieved, respectively. This paper studied the bacterial habits in a BES to better acquire and regulate the reaction process, with the aim of achieving good pollutant removal performance

Application of grey model on analyzing the passive natural circulation residual heat removal system of HTR-10

Institute of Scientific and Technical Information of China (English)

ZHOU Tao; PENG Changhong; WANG Zenghui; WANG Ruosu

2008-01-01

Using the grey correlation analysis, it can be concluded that the reactor pressure vessel wall temperature has the strongest effect on the passive residual heat removal system in HTR (High Temperature gas-cooled Reactor),the chimney height takes the second place, and the influence of inlet air temperature of the chimney is the least. This conclusion is the same as that analyzed by the traditional method. According to the grey model theory, the GM(1,1) and GM(1, 3) model are built based on the inlet air temperature of chimney, pressure vessel temperature and the chimney height. Then the effect of three factors on the heat removal power is studied in this paper. The model plays an important role on data prediction, and is a new method for studying the heat removal power. The method can provide a new theoretical analysis to the passive residual heat removal system of HTR.

Integrated removal of organic load, P, N, on a filters serial system, anaerobic, anoxic and aerobic on dynamic conditions

International Nuclear Information System (INIS)

Correa Mauricio Andres; Sierra, Jorge Humberto

2004-01-01

This paper shows the results obtained during the operation under dynamic conditions of a three biofilters serial system, anaerobic, anoxic and aerobic at lab scale to evaluate the N, P, and organic matter removal. The reactors were continuously fed for 200 days, including the adherence and stability periods, with hydraulic retention time among 2,27 and 0,66 d. for the ANABF and among 1,5 and 0,5 d. for the ANXBF. The adherence period was followed by a control of SSV and the DQO removal in each BF. After good results of adherence the system was fed with an initial average volumetric organic load of 0,441 kg DQO/m 3 /d. and gradually increase during the results of DQO removal over the 50%, until the achievement of the system stability for a maximum organic load of 1,5 kg. The reactor control was made by DQO, PO 4 3 , NTK, NO 2 , NO 3 , SS and alkalinity, determined at enter and exit of each reactor. The removal results for the system of growing adherence was among 90-96% for DQO, 80-90% for total P, and 65-70% for total N

Design of DC Conduction Pump for PGSFR Active Decay Heat Removal System

Energy Technology Data Exchange (ETDEWEB)

Kim, Dehee; Hong, Jonggan; Lee, Taeho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

A DC conduction pump has been designed for the ADHRS of PGSFR. A VBA code developed by ANL was utilized to design and optimize the pump. The pump geometry dependent parameters were optimized to minimize the total current while meeting the design requirements. A double-C type dipole was employed to produce the calculated magnetic strength. Numerical simulations for the magnetic field strength and its distribution around the dipole and for the turbulent flow under magnetic force will be carried out. A Direct Current (DC) conduction Electromagnetic Pump (EMP) has been designed for Active Decay Heat Removal System (ADHRS) of PGSFR. The PGSFR has active as well as passive systems for the DHRS. The passive DHRS (PDHRS) works by natural circulation head and the ADHRS is driven by an EMP for the DHRS sodium loop and a blower for the finned-tube sodium-to-air heat exchanger (FHX). An Annular Linear Induction Pump (ALIP) can be also considered for the ADHRS, but DC conduction pump has been chosen. Selection basis of DHRS EMP is addressed and EMP design for single ADHRS loop with 1MWt heat removal capacity is introduced.

Removal of Pharmaceutical and Personal Care Products (PPCPs) from Municipal Waste Water with Integrated Membrane Systems, MBR-RO/NF.

Science.gov (United States)

Wang, Yonggang; Wang, Xu; Li, Mingwei; Dong, Jing; Sun, Changhong; Chen, Guanyi

2018-02-05

This study focuses on the application of combining membrane bioreactor (MBR) treatment with reverse osmosis (RO) or nanofiltration (NF) membrane treatment for removal of pharmaceuticals and personal care products (PPCPs) in municipal wastewater. Twenty-seven PPCPs were measured in real influent with lowest average concentration being trimethoprim (7.12 ng/L) and the highest being caffeine (18.4 ng/L). The results suggest that the MBR system effectively removes the PPCPs with an efficiency of between 41.08% and 95.41%, and that the integrated membrane systems, MBR-RO/NF, can achieve even higher removal rates of above 95% for most of them. The results also suggest that, due to the differences in removal mechanisms of NF/RO membrane, differences of removal rates exist. In this study, the combination of MBR-NF resulted in the removal of 13 compounds to below detection limits and MBR-RO achieved even better results with removal of 20 compounds to below detection limits.

[NH4+-N removal stability of zeolite media packed multistage-biofilm system for coke-plant wastewater treatment].

Science.gov (United States)

Zhao, Wen-Tao; Huang, Xia; He, Miao; Zhang, Peng-Yi; Zuo, Chen-Yan

2009-02-15

The practical ammonia stripping effectiveness of coke-plant wastewater treatment may vary widely, and high NH4+-N shock loading will lead to the fluctuation of residual NH4+-N concentration of biological effluent. A zeolite media packed multistage-biofilm system (ZMBS) was used for coke-plant wastewater treatment for enhancing the NH4+-N treatment ability of the bio-system to shock loading, as well as achieving high COD removal efficiency. Treatment performance during steady-state and shock loading and transformation of organic pollutants in the system were investigated systematically. The experiment results indicated that when the system was operated at NH4+-N loading 0.21 kg/(m3 x d) and COD loading NH4+-N and COD concentrations were (2.2 +/- 1.2) mg/L, (228 +/- 60) mg/L with average removal efficiencies of (99.1 +/- 0.5)% and (86.0 +/- 2.6)%. During the twice NH4+-N shock loadings [0.03 kg/(m3 x d) and 0.06 kg/(m3 x d)], ZMBS showed a strong resisting ability with average removal efficiencies of 99.0% and 92.9% higher than those of a compared system's 96.8% and 89.3%. By monitoring the change of water quality along the length of the ZMBS's cells, two function zones for different pollutant removal were found to exist, named as decarbonization/nitrification (C/N) zone and nitrification (N) zone, and the NH4+-N removal rate in N zone was 2-8 times as that in C/N zone. TOC concentrations of organic matters with relative molecular weight 1 x 10(4), were 227.6, 104.8 and 35.0 mg/L in raw wastewater, and 31.2, 22.9 and 31.5 mg/L in the effluent, respectively. Organic matters with relative molecular weight 1x 10(3) were the main remained substances in the effluent.

Zero-Valent Metallic Treatment System and Its Application for Removal and Remediation of Polychlorinated Biphenyls (Pcbs)

Science.gov (United States)

Quinn, Jacqueline W. (Inventor); Clausen, Christian A. (Inventor); Geiger, Cherie L. (Inventor); Brooks, Kathleen B. (Inventor)

2012-01-01

PCBs are removed from contaminated media using a treatment system including zero-valent metal particles and an organic hydrogen donating solvent. The treatment system may include a weak acid in order to eliminate the need for a coating of catalytic noble metal on the zero-valent metal particles. If catalyzed zero-valent metal particles are used, the treatment system may include an organic hydrogen donating solvent that is a non-water solvent. The treatment system may be provided as a "paste-like" system that is preferably applied to natural media and ex-situ structures to eliminate PCBs.

Advanced phosphorus recovery using a novel SBR system with granular sludge in simultaneous nitrification, denitrification and phosphorus removal process.

Science.gov (United States)

Lu, Yong-Ze; Wang, Hou-Feng; Kotsopoulos, Thomas A; Zeng, Raymond J

2016-05-01

In this study, a novel process for phosphorus (P) recovery without excess sludge production from granular sludge in simultaneous nitrification-denitrification and P removal (SNDPR) system is presented. Aerobic microbial granules were successfully cultivated in an alternating aerobic-anaerobic sequencing batch reactor (SBR) for removing P and nitrogen (N). Dense and stable granular sludge was created, and the SBR system showed good performance in terms of P and N removal. The removal efficiency was approximately 65.22 % for N, and P was completely removed under stable operating conditions. Afterward, new operating conditions were applied in order to enhance P recovering without excess sludge production. The initial SBR system was equipped with a batch reactor and a non-woven cloth filter, and 1.37 g of CH3COONa·3H2O was added to the batch reactor after mixing it with 1 L of sludge derived from the SBR reactor to enhance P release in the liquid fraction, this comprises the new system configuration. Under the new operating conditions, 93.19 % of the P contained in wastewater was released in the liquid fraction as concentrated orthophosphate from part of granular sludge. This amount of P could be efficiently recovered in the form of struvite. Meanwhile, a deterioration of the denitrification efficiency was observed and the granules were disintegrated into smaller particles. The biomass concentration in the system increased firstly and then maintained at 4.0 ± 0.15 gVSS/L afterward. These results indicate that this P recovery operating (PRO) mode is a promising method to recover P in a SNDPR system with granular sludge. In addition, new insights into the granule transformation when confronted with high chemical oxygen demand (COD) load were provided.

Reliability and Maintainability Analysis for the Amine Swingbed Carbon Dioxide Removal System

Science.gov (United States)

Dunbar, Tyler

2016-01-01

I have performed a reliability & maintainability analysis for the Amine Swingbed payload system. The Amine Swingbed is a carbon dioxide removal technology that has gone through 2,400 hours of International Space Station on-orbit use between 2013 and 2016. While the Amine Swingbed is currently an experimental payload system, the Amine Swingbed may be converted to system hardware. If the Amine Swingbed becomes system hardware, it will supplement the Carbon Dioxide Removal Assembly (CDRA) as the primary CO2 removal technology on the International Space Station. NASA is also considering using the Amine Swingbed as the primary carbon dioxide removal technology for future extravehicular mobility units and for the Orion, which will be used for the Asteroid Redirect and Journey to Mars missions. The qualitative component of the reliability and maintainability analysis is a Failure Modes and Effects Analysis (FMEA). In the FMEA, I have investigated how individual components in the Amine Swingbed may fail, and what the worst case scenario is should a failure occur. The significant failure effects are the loss of ability to remove carbon dioxide, the formation of ammonia due to chemical degradation of the amine, and loss of atmosphere because the Amine Swingbed uses the vacuum of space to regenerate the Amine Swingbed. In the quantitative component of the reliability and maintainability analysis, I have assumed a constant failure rate for both electronic and nonelectronic parts. Using this data, I have created a Poisson distribution to predict the failure rate of the Amine Swingbed as a whole. I have determined a mean time to failure for the Amine Swingbed to be approximately 1,400 hours. The observed mean time to failure for the system is between 600 and 1,200 hours. This range includes initial testing of the Amine Swingbed, as well as software faults that are understood to be non-critical. If many of the commercial parts were switched to military-grade parts, the expected

Removal time and efficacy of Riddell Quick Release Face Guard Attachment System side clips during 1 football season.

Science.gov (United States)

Gruppen, Tonia; Smith, Molly; Ganss, Andrea

2012-01-01

In the National Athletic Trainers' Association position statement, "Acute Management of the Cervical Spine-Injured Athlete," the technique recommended for face-mask (FM) removal is one that "creates the least head and neck motion, is performed most quickly, is the least difficult, and carries the least chance of failure." Industrial and technological advances in football helmet design and FM attachment systems might influence the efficacy of emergency FM removal. To examine the removal times and success rates of the Quick Release (QR) Face Guard Attachment System (Riddell Sports, Inc, Elyria, OH) throughout and at the conclusion of 1 season of play by a National Collegiate Athletic Association Division III football team competing in the Midwest. Controlled laboratory study. College laboratory. A total of 69 randomly selected Revolution IQ (Riddell Sports, Inc) football helmets fitted with the QR system were used. Each helmet was secured to a spine board, and investigators attempted to remove both of the QR side clips from the helmet with the Riddell insertion tool. Dependent variables included total time for removal of both QR side clips from the FM and success rate for removal of both side clips. The overall success rate for removal of both clips was 94.8% (164/173), whereas the mean times for removal of both clips ranged from 9.92 ± 12.06 seconds to 16.65 ± 20.97 seconds over 4 trial sessions. We found no differences among mean times for trial sessions throughout the season of play among the same helmets or among different helmets (P > .05). Removal time and success rate of the Riddell QR were satisfactory during and after 1 season of play despite use in various temperatures and precipitation.

Removal Time and Efficacy of Riddell Quick Release Face Guard Attachment System Side Clips During 1 Football Season

Science.gov (United States)

Gruppen, Tonia; Smith, Molly; Ganss, Andrea

2012-01-01

Context In the National Athletic Trainers' Association position statement, “Acute Management of the Cervical Spine-Injured Athlete,” the technique recommended for face-mask (FM) removal is one that “creates the least head and neck motion, is performed most quickly, is the least difficult, and carries the least chance of failure.” Industrial and technological advances in football helmet design and FM attachment systems might influence the efficacy of emergency FM removal. Objective To examine the removal times and success rates of the Quick Release (QR) Face Guard Attachment System (Riddell Sports, Inc, Elyria, OH) throughout and at the conclusion of 1 season of play by a National Collegiate Athletic Association Division III football team competing in the Midwest. Design Controlled laboratory study. Setting College laboratory. Patients or Other Participants A total of 69 randomly selected Revolution IQ (Riddell Sports, Inc) football helmets fitted with the QR system were used. Intervention(s) Each helmet was secured to a spine board, and investigators attempted to remove both of the QR side clips from the helmet with the Riddell insertion tool. Main Outcome Measure(s) Dependent variables included total time for removal of both QR side clips from the FM and success rate for removal of both side clips. Results The overall success rate for removal of both clips was 94.8% (164/173), whereas the mean times for removal of both clips ranged from 9.92 ± 12.06 seconds to 16.65 ± 20.97 seconds over 4 trial sessions. We found no differences among mean times for trial sessions throughout the season of play among the same helmets or among different helmets (P > .05). Conclusions Removal time and success rate of the Riddell QR were satisfactory during and after 1 season of play despite use in various temperatures and precipitation. PMID:22889658

Regenerating an Arsenic Removal Iron-Based Adsorptive Media System, Part 1: The Regeneration Process

Science.gov (United States)

Adsorptive media technology is a frequently used method of removing arsenic by small water systems because of its simplicity and efficiency. Current practice is to replace the media when it no longer reduces arsenic below the USEPA drinking water maximum contaminant level (MCL) ...

A value/impact assessment for alternative decay heat removal systems

International Nuclear Information System (INIS)

Cave, L.; Kastenberg, W.E.; Lin, K.Y.

1984-01-01

A Value/Impact assessment for several alternative decay heat removal systems has been carried out using several measures. The assessment is based on an extension of the methodology presented in the Value/Impact Handbook and includes the effects of uncertainty. The assessment was carried out as a function of site population density, existing plant features, and new plant features. Value/Impact measures based on population dose are shown to be sensitive to site, while measures which monetize and aggregate risk are less so. The latter are dominated by on-site costs such as replacement power costs. (orig.)

Reliability analysis of emergency decay heat removal system of nuclear ship under various accident conditions

International Nuclear Information System (INIS)

Matsuoka, Takeshi

1984-01-01

A reliability analysis is given for the emergency decay heat removal system of the Nuclear Ship ''Mutsu'' and the emergency sea water cooling system of the Nuclear Ship ''Savannah'', under ten typical nuclear ship accident conditions. Basic event probabilities under these accident conditions are estimated from literature survey. These systems of Mutsu and Savannah have almost the same reliability under the normal condition. The dispersive arrangement of a system is useful to prevent the reduction of the system reliability under the condition of an accident restricted in one room. As for the reliability of these two systems under various accident conditions, it is seen that the configuration and the environmental condition of a system are two main factors which determine the reliability of the system. Furthermore, it was found that, for the evaluation of the effectiveness of safety system of a nuclear ship, it is necessary to evaluate its reliability under various accident conditions. (author)

Biofilms and Oxidizing Biocides; Evaluation of Disinfection and Removal Effects by Using Established Microbial Systems.

Science.gov (United States)

Tachikawa, Mariko

2017-01-01

The formation of bacterial biofilms and their disinfection and removal have been important subjects in the maintenance of water quality in areas such as public spas, swimming pools, food processing lines, industrial water systems, and in the hygienic control of medical devices, hospital procedures, etc. Presented here is an outline of biofilm formation, as well as studies on the disinfection and removal of biofilms by oxidizing biocides using established biofilms. These studies using established biofilms may increase the understanding of the variable response of biofilms to planktonic bacteria, and the unique aspects of oxidizing biocides in the disinfection and removal of biofilms.

Enhanced Removal of Nutrients and Trace Organics from Urban Runoff with Novel Capture, Treatment, and Recharge Systems

Science.gov (United States)

Ashoori, N.; Planes, M. T.; Lefevre, G.; Sedlak, D.; Luthy, R. G.

2017-12-01

Rapid population growth, urban sprawl and impact of climate change are forcing water-stressed areas to rely on new local sources of water supply. Under this scenario, reclamation of stormwater runoff has emerged as a source for irrigation and replenishing drinking-water groundwater reservoirs. However, urban stormwater can be a significant source of pollutants, including nutrients and organic compounds. In order to overcome the stormwater treatment system limitations, this project has developed a pilot-scale column system for passive treatment of infiltrated water using low-cost, low-energy geomedia. The objective was to provide guidance on the design and operation of systems for controlling nutrient and trace organic contaminant releases to surface waters. The work comprised of replicate column studies in the field to test stormwater treatment modules with various media, such as woodchips and biochar, using urban runoff from a watershed in Sonoma, California. Woodchip bioreactors host an endemic population of microorganisms that can be harnessed to biologically degrade nitrate. The columns amended with biochar enhance removal of organic pollutants present in stormwater through physicochemical processes (i.e., adsorption onto biochar) and biodegradation in the column through increasing retention time. The field columns were conditioned with stormwater for eight months before being spiked weekly with 50 ppb of representative trace organics. The key finding was the successful field demonstration of a novel treatment system for both the removal of nitrate and trace organics. Nitrogen removal was successful in all columns for the thirteen month experiment due to the woodchips being an effective source of carbon for denitrifying microorganisms to convert nitrate to nitrogen gases. As for the trace organics experiments, the results highlight an overall attenuation of the studied trace organic compounds by the columns containing woodchip and biochar throughout the five

Study of passive residual heat removal system of a modular small PWR reactor

International Nuclear Information System (INIS)

Araujo, Nathália N.; Su, Jian

2017-01-01

This paper presents a study on the passive residual heat removal system (PRHRS) of a small modular nuclear reactor (SMR) of 75MW. More advanced nuclear reactors, such as generation III + and IV, have passive safety systems that automatically go into action in order to prevent accidents. The purpose of the PRHRS is to transfer the decay heat from the reactor's nuclear fuel, keeping the core cooled after the plant has shut down. It starts operating in the event of fall of power supply to the nuclear station, or in the event of an unavailability of the steam generator water supply system. Removal of decay heat from the core of the reactor is accomplished by the flow of the primary refrigerant by natural circulation through heat exchangers located in a pool filled with water located above the core. The natural circulation is caused by the density gradient between the reactor core and the pool. A thermal and comparative analysis of the PRHRS was performed consisting of the resolution of the mass conservation equations, amount of movement and energy and using incompressible fluid approximations with the Boussinesq approximation. Calculations were performed with the aid of Mathematica software. A design of the heat exchanger and the cooling water tank was done so that the core of the reactor remained cooled for 72 hours using only the PRHRS

Removal of Escherichia coli via low frequency electromagnetic field in riverbank filtration system.

Science.gov (United States)

Selamat, Rossitah; Abustan, Ismail; Rizal Arshad, Mohd; Mokhtar Kamal, Nurul Hana

2018-04-01

The removal of Escherichia coli (E. coli) via low frequency of electromagnetic field (LF-EMF) with different magnetic field was studied. LF-EMF is known as a high magnetic susceptibility method, which could affect E. coli growth without the usage of chemicals. The aim of this study was to investigate the removal of E. coli by using LF-EMF in water abstraction for the riverbank filtration (RBF) application. The effect of LF-EMF with the intensity of 2 to 10mT and 50Hz on coiled column of 1mm copper wire at 1 to 6 hours was assessed. The removal of E. coli after exposing to LF-EMF on the column model was measured using most probable number (MPN/100mL) and colonies forming unit (CFU/100mL) methods. Water flows into the column were varied up to 6 hours and with flowrate of 100 mL/min. Experimental results demonstrate that 100% of E. coli was removed at 8mT after 6 hours exposure. The magnetic field at 10mT removed 100% of E. coli after 4 hours exposure. The results obtained in this study proved that the LF-EMF was efficient in E. coli removal from RBF system. These finding indicated that the LF-EMF intensities and time of exposure can affect the removal of E. coli.

Concepts for passive heat removal and filtration systems under core meltdown conditions

International Nuclear Information System (INIS)

Wilhelm, J.G.; Neitzel, H.-J.

1993-01-01

The objective of the new containment concept being developed by KfK is the complete passive enclosure of a power reactor after a core meltdown accident by means of a solid containment structure and passive removal of the decay heat. This is to be accomplished by cooling the containment walls with ambient air, with thermoconvection as the driving force. The concept of the containment is described. Data are given of the heat removal and the requirements for filtration of the exhaust air, which is contaminated due to the leak rate assumed for the inner containment. The concept for the filter system is described. Various solutions for reduction of the large volumetric flow to be filtered are discussed. 3 refs., 8 figs

Passive Decay Heat Removal Strategy of Integrated Passive Safety System (IPSS) for SBO-combined Accidents

Energy Technology Data Exchange (ETDEWEB)

Kim, Sang Ho; Chang, Soon Heung; Jeong, Yong Hoon [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2014-10-15

The weak points of nuclear safety would be in outmoded nuclear power plants like the Fukushima reactors. One of the systems for the safety enhancement is integrated passive safety system (IPSS) proposed after the Fukushima accidents. It has the five functions for the prevention and mitigation of a severe accident. Passive decay heat removal (PDHR) strategy using IPSS is proposed for coping with SBO-combined accidents in this paper. The two systems for removing decay heat before core-melt were applied in the strategy. The accidents were simulated by MARS code. The reference reactor was OPR1000, specifically Ulchin-3 and 4. The accidents included loss-of-coolant accidents (LOCA) because the coolant losses could be occurred in the SBO condition. The examples were the stuck open of PSV, the abnormal open of SDV and the leakage of RCP seal water. Also, as LOCAs with the failure of active safety injection systems were considered, various LOCAs were simulated in SBO. Based on the thermal hydraulic analysis, the probabilistic safety analysis was carried out for the PDHR strategy to estimate the safety enhancement in terms of the variation of core damage frequency. AIMS-PSA developed by KAERI was used for calculating CDF of the plant. The IPSS was applied in the PDHR strategy which was developed in order to cope with the SBO-combined accidents. The estimation for initiating SGGI or PSIS was based on the pressure in RCS. The simulations for accidents showed that the decay heat could be removed for the safety duration time in SBO. The increase of safety duration time from the strategy provides the increase of time for the restoration of AC power.

Removal of fecal indicators and pathogens in a waste stabilization pond system treating municipal wastewater in India.

Science.gov (United States)

Tyagi, Vinay Kumar; Kazmi, A A; Chopra, A K

2008-11-01

This study assess the removal of fecal indicators (i.e., total coliforms, fecal coliforms, E. coli, fecal streptococci, and pathogens [Salmonella sp. and helminth eggs]) in a full-scale facultative and maturation pond system with primary screening and manual grit removal facility. The capacity of the plant is 6 ML/d. The results showed that the system was able to remove approximately 2.0 to 3.5 log units of fecal indicators and almost 100% of helminth eggs. Meanwhile, Salmonella was not eliminated significantly, as only 1.26 log units removal was found. Removal efficiency of fecal indicator bacteria was reported maximum during summers (3.4 to 4.0 log units) and minimum (1.9 to 2.0 log units) in winters. Further efforts were made to seek the correlation between key physicochemical wastewater quality parameters (biochemical oxygen demand, turbidity, and suspended solids) and indicator microorganisms (total coliforms, fecal coliforms, and fecal streptococci). Among all these parameters, suspended solids showed the highest correlation coefficient (r2) with total coliforms (0.79), fecal coliforms (0.78), and fecal streptococci (0.75). These correlations manifest that the improvement of microbiological quality of wastewater is strongly linked to the removal of suspended solids.

Study of modified two incisions silicone oil removal with a 23G transconjunctival sutureless vitrectomy system

Directory of Open Access Journals (Sweden)

Hai-Jun Yang

2015-01-01

Full Text Available AIM:To evaluate the efficacy and safety of silicone oil removal with a 23G transconjunctival sutureless vitrectomy system linked disposable transfusion tube and self-made suction tip. METHODS: The suction tip was made with a 23G infusion tube be cut from the end of the 5mm. It was used to connect the disposable transfusion tube and 23G puncture cannula. The disposable transfusion tube which was cut from the end of the MaiFei's pipe was connected with the effusion box of the vitreous cutter. Intraocular silicone oil was proactive suction and removed through two incisions on pars plana ciliaris with the vitreous cutter suction system. RESULTS: Only 13 cases(9.8%need suture puncture ports in 132 cases in the operation. Operation time was 7-28min. The average operation time was 15.1± 6.2min. In early postoperative, there were 107 cases(81.1%appeared lower intraocular pressure(CONCLUSION: The surgery that silicone oil is removed through two incisions with a 23G transconjunctival sutureless vitrectomy system linked disposable transfusion tube and self-made suction tip has the advantages of safe, effective, fast, economic, and it is worthy of popularization and application in clinical.

Investigating the mechanism of clofibric acid removal in Fe{sup 0}/H{sub 2}O systems

Energy Technology Data Exchange (ETDEWEB)

Ghauch, Antoine, E-mail: ag23@aub.edu.lb [American University of Beirut, Faculty of Arts and Sciences, Department of Chemistry, P.O. Box 11-0236, Riad El Solh - 1107-2020, Beirut (Lebanon); Abou Assi, Hala; Tuqan, Almuthanna [American University of Beirut, Faculty of Arts and Sciences, Department of Chemistry, P.O. Box 11-0236, Riad El Solh - 1107-2020, Beirut (Lebanon)

2010-04-15

Since the introduction of iron wall technology, the inherent relationship between contaminant removal and iron corrosion has been mostly attributed to electron transfer from the metal body (direct reduction). This thermodynamically founded premise has failed to explain several experimental facts. Recently, a new concept considering adsorption and co-precipitation as fundamental contaminant removal mechanisms was introduced. This consistent concept has faced very skeptic views and necessarily needs experimental validation. The present work was the first independent attempt to validate the new concept using clofibric acid (CLO) as model compound. For this purpose, a powdered Fe{sup 0} material (Fe{sup 0}) was used in CLO removal experiments under various experimental conditions. Additional experiments were performed with plated Fe{sup 0} (mFe{sup 0}: Fe{sup 0}/Pd{sup 0}, Fe{sup 0}/Ni{sup 0}) to support the discussion of removal mechanism. Main investigated experimental variables included: abundance of O{sub 2}, abundance of iron corrosion products (ICPs) and shaking operations. Results corroborated the concept that quantitative contaminant removal in Fe{sup 0}/H{sub 2}O systems occurs within the oxide-film in the vicinity of Fe{sup 0}. Additionally, mixing type and shaking intensity significantly influenced the extent of CLO removal. More importantly, HPLC/MS revealed that the identity of reaction products depends on the extent of iron corrosion or the abundance of ICPs. The investigation of the CLO/Fe{sup 0}/H{sub 2}O system disproved the popular view that direct reduction mediates contaminant removal in the presence of Fe{sup 0}.

CAREM 25: Design of resin bed for purification and boron removal systems

International Nuclear Information System (INIS)

Chocron, Mauricio; Iglesias, Alberto M.; Jimenez Rebagliati, Raul; Raffo Calderon, Maria C.; La Gamma, Ana M.

2000-01-01

The purification of the water the primary coolant of a water cooled nuclear reactor as well as the water of many auxiliary systems is controlled by the use of ion exchange resins. In the present paper, the resin beds for three different systems are specified: the purification and control volume system, the suppression pool water and the spent fuel pool water for the reactor CAREM-25. In all cases the dimensioning calculations have been done taking in consideration the amount of contaminants and corrosion products generated under normal operation or post-accident. Also, the results have been contrasted with the experience of the nuclear power plants in operation in Argentina, international design criteria and international standards. For the primary coolant, the boron-removal beds have been sized and an estimation of the maximum dose received by the resins have been calculated. It have been found that the result is well below the damaging threshold reported in the literature. (author)

BOA: Asbestos pipe-insulation removal robot system. Phase I. Topical report, November 1993--December 1994

International Nuclear Information System (INIS)

Schempf, H.; Bares, J.E.

1995-01-01

Based on several key design criteria and site visits, we developed a Robot design and built a system which automatically strips the lagging and insulation from the pipes, and encapsulates them under complete vacuum operation. The system can operate on straight runs of piping in horizontal or vertical orientations. Currently we are limited to four-inch diameter piping without obstacles as well as a somewhat laborious emplacement and removal procedure. Experimental results indicated that the current robotic abatement process is sound yet needs to be further expanded and modified. One of the main discoveries was that a longitudinal cut to fully allow the paddles to dig in and compress the insulation off the pipe is essential. Furthermore, a different cutting method might be explored to alleviate the need for a deeper cut and to enable a combination of certain functions such as compression and cutting. Unfortunately due to a damaged mechanism caused by extensive testing, we were unable to perform vertical piping abatement experiments, but foresee no trouble in implementing them in the next proposed Phase. Other encouraging results have BOA removing asbestos at a rate of 4-5 ft./h compared to 3 ft./h for manual removal of asbestos with a 3-person crew. However, we feel confident that we can double the asbestos removal rate by improving cutting speed, and increasing the length of the BOA robot. The containment and vacuum system on BOA is able to achieve the regulatory requirement for airborne fiber emissions of 0.01 fibers/ccm/8-hr. shift. Currently, BOA weighs about 117 pounds which is more than a human is permitted to lift overhead under OSHA requirements (i.e., 25 pounds). We are considering designing the robot into two components (i.e., locomotor section and cutter/removal section) to aid human installation as well as incorporating composite materials. A more detailed list of all the technical modifications is given in this topical report

BOA: Asbestos pipe-insulation removal robot system. Phase I. Topical report, November 1993--December 1994

Energy Technology Data Exchange (ETDEWEB)

Schempf, H.; Bares, J.E.

1995-01-01

Based on several key design criteria and site visits, we developed a Robot design and built a system which automatically strips the lagging and insulation from the pipes, and encapsulates them under complete vacuum operation. The system can operate on straight runs of piping in horizontal or vertical orientations. Currently we are limited to four-inch diameter piping without obstacles as well as a somewhat laborious emplacement and removal procedure. Experimental results indicated that the current robotic abatement process is sound yet needs to be further expanded and modified. One of the main discoveries was that a longitudinal cut to fully allow the paddles to dig in and compress the insulation off the pipe is essential. Furthermore, a different cutting method might be explored to alleviate the need for a deeper cut and to enable a combination of certain functions such as compression and cutting. Unfortunately due to a damaged mechanism caused by extensive testing, we were unable to perform vertical piping abatement experiments, but foresee no trouble in implementing them in the next proposed Phase. Other encouraging results have BOA removing asbestos at a rate of 4-5 ft./h compared to 3 ft./h for manual removal of asbestos with a 3-person crew. However, we feel confident that we can double the asbestos removal rate by improving cutting speed, and increasing the length of the BOA robot. The containment and vacuum system on BOA is able to achieve the regulatory requirement for airborne fiber emissions of 0.01 fibers/ccm/8-hr. shift. Currently, BOA weighs about 117 pounds which is more than a human is permitted to lift overhead under OSHA requirements (i.e., 25 pounds). We are considering designing the robot into two components (i.e., locomotor section and cutter/removal section) to aid human installation as well as incorporating composite materials. A more detailed list of all the technical modifications is given in this topical report.

Scale analysis of decay heat removal system between HTR-10 and HTR-PM reactors under accidental conditions

International Nuclear Information System (INIS)

Roberto, Thiago D.; Alvim, Antonio C.M.

2017-01-01

The 10 MW high-temperature gas-cooled test module (HTR-10) is a graphite-moderated and helium-cooled pebble bed reactor prototype that was designed to demonstrate the technical and safety feasibility of this type of reactor project under normal and accidental conditions. In addition, one of the systems responsible for ensuring the safe operation of this type of reactor is the passive decay heat removal system (DHRS), which operates using passive heat removal processes. A demonstration of the heat removal capacity of the DHRS under accidental conditions was analyzed based on a benchmark problem for design-based accidents on an HTR-10, i.e., the pressurized loss of forced cooling (PLOFC) described in technical reports produced by the International Atomic Energy Agency. In fact, the HTR-10 is also a proof-of-concept reactor for the high-temperature gas-cooled reactor pebble-bed module (HTR-PM), which generates approximately 25 times more heat than the HTR-10, with a thermal power of 250 MW, thereby requiring a DHRS with a higher system capacity. Thus, because an HTR-10 is a prototype reactor for an HTR-PM, a scaling analysis of the heat transfer process from the reactor to the DHRS was carried out between the HTR-10 and HTR-PM systems to verify the distortions of scale and the differences between the main dimensionless numbers from the two projects. (author)

Scale analysis of decay heat removal system between HTR-10 and HTR-PM reactors under accidental conditions

Energy Technology Data Exchange (ETDEWEB)

Roberto, Thiago D.; Alvim, Antonio C.M. [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Lapa, Celso M.F., E-mail: thiagodbtr@gmail.com, E-mail: lapa@ien.gov.br, E-mail: alvim@nuclear.ufrj.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-07-01

The 10 MW high-temperature gas-cooled test module (HTR-10) is a graphite-moderated and helium-cooled pebble bed reactor prototype that was designed to demonstrate the technical and safety feasibility of this type of reactor project under normal and accidental conditions. In addition, one of the systems responsible for ensuring the safe operation of this type of reactor is the passive decay heat removal system (DHRS), which operates using passive heat removal processes. A demonstration of the heat removal capacity of the DHRS under accidental conditions was analyzed based on a benchmark problem for design-based accidents on an HTR-10, i.e., the pressurized loss of forced cooling (PLOFC) described in technical reports produced by the International Atomic Energy Agency. In fact, the HTR-10 is also a proof-of-concept reactor for the high-temperature gas-cooled reactor pebble-bed module (HTR-PM), which generates approximately 25 times more heat than the HTR-10, with a thermal power of 250 MW, thereby requiring a DHRS with a higher system capacity. Thus, because an HTR-10 is a prototype reactor for an HTR-PM, a scaling analysis of the heat transfer process from the reactor to the DHRS was carried out between the HTR-10 and HTR-PM systems to verify the distortions of scale and the differences between the main dimensionless numbers from the two projects. (author)

Arsenic removal by discontinuous ZVI two steps system for drinking water production at household scale.

Science.gov (United States)

Casentini, Barbara; Falcione, Fabiano Teo; Amalfitano, Stefano; Fazi, Stefano; Rossetti, Simona

2016-12-01

Different countries in Europe still suffer of elevated arsenic (As) concentration in groundwaters used for human consumption. In the case of households not connected to the distribution system, decentralized water supply systems, such as Point of Use (POU) and Point of Entry (POE), offer a direct benefit for the consumers. Field scale ex-situ treatment systems based on metallic iron (ZVI) are already available for the production of reduced volumes of drinking water in remote areas (village scale). To address drinking water needs at larger scale, we designed a pilot unit able to produce an elevated daily volume of water for human consumption. We tested the long-term As removal efficiency of a two steps ZVI treatment unit for the production of 400 L/day clean water based on the combination of ZVI corrosion process with sedimentation and retention of freshly formed Fe precipitates. The system treated 100 μg/L As(V)-contaminated oxic groundwater in a discontinuous operation mode at a flow rate of 1 L/min for 31 days. Final removal was 77-96% and the most performing step was aeration/sedimentation (A/S) tank with a 60-94% efficiency. Arsenic in the outflow slightly exceeded the drinking water limit of 10 μg/L only after 6000 L treated and Fe concentration was always below 0.2 mg/L. Under proposed operating conditions ZVI passivation readily occurred and, as a consequence, Fe production sharply decreased. Arsenic mobility attached to particulate was 13-60% after ZVI column and 37-100% after A/S tank. Uniform amorphous cluster of Fe nanoparticles (100 nm) formed during aeration drove As removal process with an adsorption capacity corresponding to 20.5 mg As /g Fe . Research studies often focus only on chemico-physical aspects disregarding the importance of biological processes that may co-occur and interfere with ZVI corrosion, As removal and safe water production. We explored the microbial transport dynamics by flow cytometry, proved as a suitable tool 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.

Technical specification improvements to containment heat removal and emergency core cooling systems: Final report

International Nuclear Information System (INIS)

Sullivan, W.P.; Ha, C.; Pentzien, D.C.; Visweswaran, S.

1988-07-01

This report presents the results of an analysis for technical specification improvements to the emergency core cooling systems (ECCS) and containment heat removal systems (EPRI Research Project 2142-3). The objective of this project is to further develop a reliability- and risk-based methodology to provide improvements by considering groups of surveillance test intervals and allowed out-of-service times jointly. This was done for the technical specifications for the ECCS, containment heat removal equipment, and supporting systems of a boiling water reactor plant. The project (1) developed a methodology for optimizing groups of surveillance test intervals and allowed out-of-service times jointly, (2) applied the methodology in a case study of a specific operating plant, Hatch-2, and (3) evaluated benefits of the application. The results of the case study demonstrate that beneficial technical specification improvements can be realized with application of the methodology. By tightening a small group of sensitive surveillance test intervals (STIs) and allowed out-of-service times (AOTs), a larger group of less sensitive STIs and AOTs can be extended resulting in an overall plant operating cost improvement without reducing the plant safety. The reliability- and risk-based methodology and results from this project can be effectively applied for technical specification improvements at other operating plants

Survey and Down-Selection of Acid Gas Removal Systems for the Thermochemical Conversion of Biomass to Ethanol with a Detailed Analysis of an MDEA System

Energy Technology Data Exchange (ETDEWEB)

Nexant, Inc., San Francisco, California

2011-05-01

The first section (Task 1) of this report by Nexant includes a survey and screening of various acid gas removal processes in order to evaluate their capability to meet the specific design requirements for thermochemical ethanol synthesis in NREL's thermochemical ethanol design report (Phillips et al. 2007, NREL/TP-510-41168). MDEA and selexol were short-listed as the most promising acid-gas removal agents based on work described in Task 1. The second report section (Task 2) describes a detailed design of an MDEA (methyl diethanol amine) based acid gas removal system for removing CO2 and H2S from biomass-derived syngas. Only MDEA was chosen for detailed study because of the available resources.

Development and validation of models for simulation of supercritical carbon dioxide Brayton cycles and application to self-propelling heat removal systems in boiling water reactors

International Nuclear Information System (INIS)

Venker, Jeanne

2015-01-01

The objective of the current work was to develop a model that is able to describe the transient behavior of supercritical carbon dioxide (sCO 2 ) Brayton cycles, to be applied to self-propelling residual heat removal systems in boiling water reactors. The developed model has been implemented into the thermohydraulic system code ATHLET. By means of this improved ATHLET version, novel residual heat removal systems, which are based on closed sCO 2 Brayton cycles, can be assessed as a retrofit measure for present light water reactors. Transient simulations are hereby of great importance. The heat removal system has to be modeled explicitly to account for the interaction between the system and the behavior of the plant during different accident conditions. As a first step, transport and thermodynamic fluid properties of supercritical carbon dioxide have been implemented in ATHLET to allow for the simulation of the new working fluid. Additionally, a heat transfer correlation has been selected to represent the specific heat transfer of supercritical carbon dioxide. For the calculation of pressure losses due to wall friction, an approach for turbulent single phase flow has been adopted that is already implemented in ATHLET. In a second step, a component model for radial compressors has been implemented in the system code. Furthermore, the available model for axial turbines has been adapted to simulate the transient behavior of radial turbines. All extensions have been validated against experimental data. In order to simulate the interaction between the self-propelling heat removal system and a generic boiling water reactor, the components of the sCO 2 Brayton cycle have been dimensioned with first principles. An available input deck of a generic BWR has then been extended by the residual heat removal system. The modeled application has shown that the extended version of ATHLET is suitable to simulate sCO 2 Brayton cycles and to evaluate the introduced heat removal system

Functional bacteria and process metabolism of the Denitrifying Sulfur conversion-associated Enhanced Biological Phosphorus Removal (DS-EBPR) system: An investigation by operating the system from deterioration to restoration.

Science.gov (United States)

Guo, Gang; Wu, Di; Hao, Tianwei; Mackey, Hamish Robert; Wei, Li; Wang, Haiguang; Chen, Guanghao

2016-05-15

A sulfur conversion-associated Enhanced Biological Phosphorus (P) Removal (EBPR) system is being developed to cater for the increasing needs to treat saline/brackish wastewater resulting from seawater intrusion into groundwater and sewers and frequent use of sulfate coagulants during drinking water treatment, as well as to meet the demand for eutrophication control in warm climate regions. However, the major functional bacteria and metabolism in this emerging biological nutrient removal system are still poorly understood. This study was thus designed to explore the functional microbes and metabolism in this new EBPR system by manipulating the deterioration, failure and restoration of a lab-scale system. This was achieved by changing the mixed liquor suspended solids (MLSS) concentration to monitor and evaluate the relationships among sulfur conversion (including sulfate reduction and sulfate production), P removal, variation in microbial community structures, and stoichiometric parameters. The results show that the stable Denitrifying Sulfur conversion-associated EBPR (DS-EBPR) system was enriched by sulfate-reducing bacteria (SRB) and sulfide-oxidizing bacteria (SOB). These bacteria synergistically participated in this new EBPR process, thereby inducing an appropriate level of sulfur conversion crucial for achieving a stable DS-EBPR performance, i.e. maintaining sulfur conversion intensity at 15-40 mg S/L, corresponding to an optimal sludge concentration of 6.5 g/L. This range of sulfur conversion favors microbial community competition and various energy flows from internal polymers (i.e. polysulfide or elemental sulfur (poly-S(2-)/S(0)) and poly-β-hydroxyalkanoates (PHA)) for P removal. If this range was exceeded, the system might deteriorate or even fail due to enrichment of glycogen-accumulating organisms (GAOs). Four methods of restoring the failed system were investigated: increasing the sludge concentration, lowering the salinity or doubling the COD

Evaluation of the antimicrobial removal device when used with the BACTEC blood culture system

International Nuclear Information System (INIS)

Strand, C.L.

1982-01-01

A study to determine the value of the Antimicrobial Removal Device (ARD) used in conjunction with radiometric detection of bacteremia using three media was conducted. During a 12-month period, 622 duplicate ARD/BACTEC blood-culture sets were collected. There were 88 positive cultures that yielded 68 pathogenic isolates and 28 probable contaminant isolates. When all patients were considered, 31 pathogenic isolates were detected by both systems, 25 pathogenic isolates were detected faster or only by the BACTEC system, and 12 pathogenic isolates were detected faster or only when the ARD was employed. This difference is statistically significant (P less than 0.05). Thus, the standard BACTEC blood-culture system using three different media was superior to the same BACTEC system using ARD-processed blood specimens. When only patients receiving antimicrobial therapy were considered, there were more pathogenic isolates detected from unprocessed blood than from blood processed in the ARD; however, this difference was not statistically significant. In conclusion, there appears to be no advantage to using the ARD system in conjunction with the three-bottle BACTEC blood-culture system

Heat removal performance of auxiliary cooling system for the high temperature engineering test reactor during scrams

International Nuclear Information System (INIS)

Takeda, Takeshi; Tachibana, Yukio; Iyoku, Tatsuo; Takenaka, Satsuki

2003-01-01

The auxiliary cooling system of the high temperature engineering test reactor (HTTR) is employed for heat removal as an engineered safety feature when the reactor scrams in an accident when forced circulation can cool the core. The HTTR is the first high temperature gas-cooled reactor in Japan with reactor outlet gas temperature of 950 degree sign C and thermal power of 30 MW. The auxiliary cooling system should cool the core continuously avoiding excessive cold shock to core graphite components and water boiling of itself. Simulation tests on manual trip from 9 MW operation and on loss of off-site electric power from 15 MW operation were carried out in the rise-to-power test up to 20 MW of the HTTR. Heat removal characteristics of the auxiliary cooling system were examined by the tests. Empirical correlations of overall heat transfer coefficients were acquired for a helium/water heat exchanger and air cooler for the auxiliary cooling system. Temperatures of fluids in the auxiliary cooling system were predicted on a scram event from 30 MW operation at 950 degree sign C of the reactor outlet coolant temperature. Under the predicted helium condition of the auxiliary cooling system, integrity of fuel blocks among the core graphite components was investigated by stress analysis. Evaluation results showed that overcooling to the core graphite components and boiling of water in the auxiliary cooling system should be prevented where open area condition of louvers in the air cooler is the full open

Horizontal Heat Exchanger Design and Analysis for Passive Heat Removal Systems

Energy Technology Data Exchange (ETDEWEB)

Vierow, Karen

2005-08-29

This report describes a three-year project to investigate the major factors of horizontal heat exchanger performance in passive containment heat removal from a light water reactor following a design basis accident LOCA (Loss of Coolant Accident). The heat exchanger studied in this work may be used in advanced and innovative reactors, in which passive heat removal systems are adopted to improve safety and reliability The application of horizontal tube-bundle condensers to passive containment heat removal is new. In order to show the feasibility of horizontal heat exchangers for passive containment cooling, the following aspects were investigated: 1. the condensation heat transfer characteristics when the incoming fluid contains noncondensable gases 2. the effectiveness of condensate draining in the horizontal orientation 3. the conditions that may lead to unstable condenser operation or highly degraded performance 4. multi-tube behavior with the associated secondary-side effects This project consisted of two experimental investigations and analytical model development for incorporation into industry safety codes such as TRAC and RELAP. A physical understanding of the flow and heat transfer phenomena was obtained and reflected in the analysis models. Two gradute students (one funded by the program) and seven undergraduate students obtained research experience as a part of this program.

Removable splint with locking attachments for maxillary distraction osteogenesis with the RED system.

Science.gov (United States)

Suzuki, E Y; Suzuki, B

2007-12-01

The external traction hooks of the intraoral splint used to control traction forces applied to the maxilla with the rigid external distraction system represent a major barrier to surgical procedures. The purpose of this article is to introduce a removable intraoral splint with locking attachments that can be placed post-surgically immediately before distraction, facilitating surgery and consequently reducing the operative time. Fifteen cleft lip and palate patients underwent maxillary distraction osteogenesis using a rigid external distraction device in combination with the proposed removable splint that was fixed onto the maxillary teeth to provide anchorage. Initial records showed severe maxillary hypoplasia and negative overjet. The removable splint was fabricated using 1.5-mm diameter stainless-steel rigid orthodontic wires soldered to the locking attachments (Y&B Products LP, Chiang Mai, Thailand), making possible its placement post-surgically. Stable splint fixation was achieved prior to the distraction procedure and the desired treatment goals were reached. No complications inserting or removing the splint post-surgically, including pain or discomfort, were observed. The use of the removable splint with locking attachments has proved to be a highly effective fixation approach to manage the severely hypoplastic maxilla, eliminating lip constraints resulting from scarring, and allowing for easier, more deliberate and careful dissection.

Reliability study of a special decay heat removal system of a gas-cooled fast reactor demonstrator

Energy Technology Data Exchange (ETDEWEB)

Burgazzi, Luciano, E-mail: luciano.burgazzi@enea.it

2014-12-15

The European roadmap toward the development of generation IV concepts addresses the safety and reliability assessment of the special system designed for decay heat removal of a gas-cooled fast reactor demonstrator (GFRD). The envisaged system includes the combination of both active and passive means to accomplish the fundamental safety function. Failure probabilities are calculated on various system configurations, according to either pressurized or depressurized accident events under investigation, and integrated with probabilities of occurrence of corresponding hardware components and natural circulation performance assessment. The analysis suggests the improvement of measures against common cause failures (CCF), in terms of an appropriate diversification among the redundant systems, to reduce the system failure risk. Particular emphasis is placed upon passive system reliability assessment, being recognized to be still an open issue, and the approach based on the functional reliability is adopted to address the point. Results highlight natural circulation as a challenging factor for the decay heat removal safety function accomplishment by means of passive devices. With the models presented here, the simplifying assumptions and the limited scenarios considered according to the level of definition of the design, where many systems are not yet established, one can conclude that attention has to be paid to the functional aspects of the passive system, i.e. the ones not pertaining to the “hardware” of the system. In this article the results of the analysis are discussed, where the effects of the analytical assumptions, design options, accident managements on the reliability are examined. The design diversity of the components undergoing CCFs can be effective for the improvement and some accident management measures are also possible by making use of the long grace period in GFRD.

Application of vascular aquatic plants for pollution removal, energy and food production in a biological system

Science.gov (United States)

Wolverton, B. C.; Barlow, R. M.; Mcdonald, R. C.

1975-01-01

Vascular aquatic plants such as water hyacinths (Eichhornia crassipes) (Mart.) Solms and alligator weeds (Alternanthera philoxeroides) (Mart.) Griesb., when utilized in a controlled biological system (including a regular program of harvesting to achieve maximum growth and pollution removal efficiency), may represent a remarkably efficient and inexpensive filtration and disposal system for toxic materials and sewage released into waters near urban and industrial areas. The harvested and processed plant materials are sources of energy, fertilizer, animal feed, and human food. Such a system has industrial, municipal, and agricultural applications.

Model-based optimization biofilm based systems performing autotrophic nitrogen removal using the comprehensive NDHA model

DEFF Research Database (Denmark)

Valverde Pérez, Borja; Ma, Yunjie; Morset, Martin

Completely autotrophic nitrogen removal (CANR) can be obtained in single stage biofilm-based bioreactors. However, their environmental footprint is compromised due to elevated N2O emissions. We developed novel spatially explicit biochemical process model of biofilm based CANR systems that predicts...

Obliged Removal of the Percutaneous Fixation System on the Thoracolumbar Junction in Patients with Idiopathic Scoliosis

Directory of Open Access Journals (Sweden)

Alessandro Landi

2016-12-01

Full Text Available Introduction Minimally invasive percutaneous surgery of the spine is used to treat thoracolumbar junction and lumbar spine fractures by percutaneous fixation. Once fusion has been obtained, it is possible to remove the percutaneous instrumentation after 6 - 12 months. We report the case of an obliged removal of the fixation system at 12 months following operation in a patient with a pre-existing compensated and asymptomatic idiopathic scoliosis. Case Presentation A 48-year-old patient affected by a compensated asymptomatic idiopathic scoliosis with an L3 type A3 fracture. The patient underwent a percutaneous short fixation L2 - L4. In the following months the patient presented progressive worsening of the low back pain and walking difficulties. The percutaneous fixation system was then removed using the same surgical access. Conclusions This particular case explains well the importance of biomechanical balance when a spinal fixation should be perform, and demonstrate how an underestimation of this aspect may cause a worsening of symptoms even if the surgical procedure was correctly performed. It is evident that the removal procedure can lead clinical benefit to a patient, in which the fixation system created a decompensation of the curvature of the spine, thus causing biomechanical alterations and generating pain. In these cases, it may be opportune to limit the fracture reduction during the surgical procedure to modify the least possible the pre-existing scoliosis and to increase the patient’s comfort after the operation. The biomechanical behaviour of the spine is specific for each patient so only a careful detection of it could lead to an optimal therapeutic result.

Development and validation of models for simulation of supercritical carbon dioxide Brayton cycles and application to self-propelling heat removal systems in boiling water reactors

Energy Technology Data Exchange (ETDEWEB)

Venker, Jeanne

2015-03-31

The objective of the current work was to develop a model that is able to describe the transient behavior of supercritical carbon dioxide (sCO{sub 2}) Brayton cycles, to be applied to self-propelling residual heat removal systems in boiling water reactors. The developed model has been implemented into the thermohydraulic system code ATHLET. By means of this improved ATHLET version, novel residual heat removal systems, which are based on closed sCO{sub 2} Brayton cycles, can be assessed as a retrofit measure for present light water reactors. Transient simulations are hereby of great importance. The heat removal system has to be modeled explicitly to account for the interaction between the system and the behavior of the plant during different accident conditions. As a first step, transport and thermodynamic fluid properties of supercritical carbon dioxide have been implemented in ATHLET to allow for the simulation of the new working fluid. Additionally, a heat transfer correlation has been selected to represent the specific heat transfer of supercritical carbon dioxide. For the calculation of pressure losses due to wall friction, an approach for turbulent single phase flow has been adopted that is already implemented in ATHLET. In a second step, a component model for radial compressors has been implemented in the system code. Furthermore, the available model for axial turbines has been adapted to simulate the transient behavior of radial turbines. All extensions have been validated against experimental data. In order to simulate the interaction between the self-propelling heat removal system and a generic boiling water reactor, the components of the sCO{sub 2} Brayton cycle have been dimensioned with first principles. An available input deck of a generic BWR has then been extended by the residual heat removal system. The modeled application has shown that the extended version of ATHLET is suitable to simulate sCO{sub 2} Brayton cycles and to evaluate the introduced

Low concentration volatile organic pollutants removal in combined adsorber-desorber-catalytic reactor system

Directory of Open Access Journals (Sweden)

Arsenijević Zorana

2008-01-01

Full Text Available The removal of volatile organic compounds (VOCs from numerous emission sources is of crucial importance due to more rigorous demands on air quality. Different technologies can be used to treat the VOCs from effluent gases: absorption, physical adsorption, open flame combustion, thermal and catalytic incineration. Their appropriateness for the specific process depends on several factors such as efficiency, energy consumption, secondary pollution, capital investments etc. The distinctive features of the catalytic combustion are high efficiency and selectivity toward be­nign products, low energy consumption and absence of secondary polluti­on. The supported noble catalysts are widely used for catalytic incineration due to their low ignition temperatures and high thermal and chemical stability. In our combined system adsorption and desorption are applied in the spouted bed with draft tube (SBDT unit. The annular zone, loaded with sorbent, was divided in adsorption and desorption section. Draft tube enabled sorbent recirculation between sections. Combustion of desorbed gases to CO2 and water vapor are realized in additive catalytic reactor. This integrated device provided low concentrations VOCs removal with reduced energy consumption. Experiments were conducted on a pilot unit of 220 m3/h nominal capacity. The sorbent was activated carbon, type K81/B - Trayal Corporation, Krusevac. A sphere shaped commercial Pt/Al2O3 catalyst with "egg-shell" macro-distribution was used for the investigation of xylene deep oxidation. Within this paper the investigations of removal of xylene vapors, a typical pollutant in production of liquid pesticides, in combined adsorber/desorber/catalytic reactor system is presented.

75 FR 73972 - Hazardous Waste Management System; Identification and Listing of Hazardous Waste; Removal of...

Science.gov (United States)

2010-11-30

... Waste Management System; Identification and Listing of Hazardous Waste; Removal of Direct Final.... Lists of Subjects in 40 CFR Part 261 Environmental Protection, Hazardous waste, Recycling, Reporting and... follows: PART 261--IDENTIFICATION AND LISTING OF HAZARDOUS WASTE 0 1. The authority citation for part 261...

Studies on the characteristics of the separated heat pipe system with non-condensible gas for the use of the passive decay heat removal in reactor systems

International Nuclear Information System (INIS)

Hayashi, Takao; Ishi, Takayuki; Hayakawa, Hitoshi; Ohashi, Kazutaka

1997-01-01

Experiments on the separated heat pipe system of variable conductance type, which enclose non-condensible gas, have been carried out with intention of applying such system to passive decay heat removal of the modular reactors such as HTR plant. Basic experiments have been carried out on the experimental apparatus consisting of evaporator, vapor transfer tube, condenser tube and return tube which returns the condensed liquid back to the evaporator. Water and methanol were examined as the working fluids and nitrogen gas was enclosed as the non-condensible gas. The behaviors of the system were examined for the parametric changes of the heat input under the various pressures of nitrogen gas initially enclosed, including the case without enclosing N 2 gas for the comparison. The results of the experiments shows very clear features of self control characteristics. The self control mechanism was made clear, that is, in such system in which the condensing area in the condenser expands automatically in accordance with the increase of the heat input to keep the system temperature nearly constant. The working temperature of the system are clearly dependent on the pressure of the non-condensable gas initially enclosed, with higher system working temperature with higher initial gas pressure enclosed. The analyses were done on water and methanol as the working fluids, which show very good agreement with the experimental results. A lot of attractive applications are expected including the self switching feature with minimum heat loss during normal operation with maintaining the sufficient heat removal at accidents. (author)

A case study of enteric virus removal and insights into the associated risk of water reuse for two wastewater treatment pond systems in Bolivia.

Science.gov (United States)

Symonds, E M; Verbyla, M E; Lukasik, J O; Kafle, R C; Breitbart, M; Mihelcic, J R

2014-11-15

Wastewater treatment ponds (WTP) are one of the most widespread treatment technologies in the world; however, the mechanisms and extent of enteric virus removal in these systems are poorly understood. Two WTP systems in Bolivia, with similar overall hydraulic retention times but different first stages of treatment, were analyzed for enteric virus removal. One system consisted of a facultative pond followed by two maturation ponds (three-pond system) and the other consisted of an upflow anaerobic sludge blanket (UASB) reactor followed by two maturation (polishing) ponds (UASB-pond system). Quantitative polymerase chain reaction with reverse transcription (RT-qPCR) was used to measure concentrations of norovirus, rotavirus, and pepper mild mottle virus, while cell culture methods were used to measure concentrations of culturable enteroviruses (EV). Limited virus removal was observed with RT-qPCR in either system; however, the three-pond system removed culturable EV with greater efficiency than the UASB-pond system. The majority of viruses were not associated with particles and only a small proportion was associated with particles larger than 180 μm; thus, it is unlikely that sedimentation is a major mechanism of virus removal. High concentrations of viruses were associated with particles between 0.45 and 180 μm in the UASB reactor effluent, but not in the facultative pond effluent. The association of viruses with this size class of particles may explain why only minimal virus removal was observed in the UASB-pond system. Quantitative microbial risk assessment of the treated effluent for reuse for restricted irrigation indicated that the three-pond system effluent requires an additional 1- to 2-log10 reduction of viruses to achieve the WHO health target of <10(-4) disability-adjusted life years (DALYs) lost per person per year; however, the UASB-pond system effluent may require an additional 2.5- to 4.5-log10 reduction of viruses. Copyright © 2014 Elsevier Ltd. All

Iodine removal in containment filtered venting system during nuclear accident

International Nuclear Information System (INIS)

Bera, Subrata; Deo, Anuj Kumar; Nagrale, D.B.; Paul, U.K.; Prasad, M.; Gaikwad, A.J.

2015-01-01

Post Fukushima nuclear accident, containment filtered venting system is being introduced in Indian nuclear power plant to strengthen the defense in depth safety barrier by depressurizing the containment building along with minimization of radioactivity release to environment during a severe accident. Radioactive iodine is one of the major contributors to radiation dose during early release phase of a severe accident. Physical and Chemical form of iodine and iodine bearing compounds includes particulates, elemental and organic. In the most efficient design of CFVS, wet scrubbing mechanism has been employed through use of venture scrubber. The Iodine removal process in wet scrubber involves two processes: chemical reaction in highly alkaline aqueous solution and impingement of particulates with water droplets produced in the venturi nozzle. In this paper, venturi has been modeled using the Calvert model. The variation of efficiency has been estimated for the different particle sizes. The impact of the shape parameter of log-normal distribution on the amount of scrubbed iodine has also been assessed. Release phase wise the scrubbed amount of iodine in the venturi based CFVS system has been estimated for a typical BWR. (author)

Environmentally friendly technology and equipment of the system of spent FA waste removal for storage at the RT plant

International Nuclear Information System (INIS)

Vovkotrub, Yu.G.; Dorokhin, V.I.; Istomin, V.L.; Markov, B.V.; Samokhotov, S.A.

1999-01-01

Systems having no world analog for removal and disposal of spent fuel assembly tailings and insoluble fragments of crushed fuel element claddings, which have been put into service at radiotechnical plant of Mayak PA, are described. The tailings are brought to a repository by a dolly moving inside a piping (box) using linear asynchronous electric motors, while insoluble fragments are removed via the piping using pulsed pneumatic transportation. It is pointed out that the systems described comply with today's requirements in terms of environmental protection and creation of conditions favorable for the personnel work [ru

Integrated constructed wetland systems: design, operation, and performance of low-cost decentralized wastewater treatment systems.

Science.gov (United States)

Behrends, L L; Bailey, E; Jansen, P; Houke, L; Smith, S

2007-01-01

Several different types of constructed wetland systems are being used as decentralized treatment systems including surface-flow, subsurface-flow, vertical-flow, and hybrid systems. Archetypical wetland systems have design strengths and weaknesses, and therefore it should be possible to design combined (integrated) systems to optimize a number of important treatment processes. This study provides comparative efficacy data for two integrated wetland treatment systems (IWTS) designed to enhance treatment of medium strength wastewater generated from a pilot-scale intensive fish farm. Results from the twenty eight months study included consistently high removal of COD (84% +) and ammonia nitrogen (93%) in both systems. Initially, phosphorus removal was also high (>90%) in both systems, but removal efficacy declined significantly over time. Nitrate removal was significantly better in the system that provided sequential aerobic and anoxic environments. Short hydraulic retention times coupled with sustained removal of COD and ammonia indicate that the ReCip components could be a least-cost wastewater treatment technology in the decentralized market sector.

Economic assessment of biogas-to-electricity generation system with H2S removal by activated carbon in small pig farm

International Nuclear Information System (INIS)

Pipatmanomai, Suneerat; Kaewluan, Sommas; Vitidsant, Tharapong

2009-01-01

This study was conducted to assess the economic feasibility of electricity generation from biogas in small pig farms with and without the H 2 S removal prior to biogas utilisation. The 2% potassium iodide (KI) impregnated activated carbon selected as H 2 S adsorbent was introduced to a biogas-to-electricity generation system in a small pig farm in Thailand as a case study. With the average inlet H 2 S concentration of about 2400 ppm to the adsorption unit, the H 2 S removal efficiency could reach 100% with the adsorption capacity of 0.062 kg of H 2 S/kg of adsorbent. Under the reference scenario (i.e., 45% subsidy on digester installation and fixed electricity price at 0.06 Euro/kWh) and based on an assumption that the biogas was fully utilised for electricity generation in the system, the payback period for the system without H 2 S removal was about 4 years. With H 2 S removal, the payback period was within the economic life of digester but almost twice that of the case without H 2 S removal. The impact of electricity price could be clearly seen for the case of treated biogas. At the electricity price fixed at 0.07 Euro/kWh, the payback period for the case of treated biogas was reduced to about 5.5 years, with a trend to decrease at higher electricity prices. For both treated and untreated biogas, the governmental subsidy was the important factor determining the economics of the biogas-to-electricity systems. Without subsidy, the payback period increased to almost 7 years and about 11 years for the case of untreated and treated biogas, respectively, at the reference electricity price. Although the H 2 S removal added high operation cost to the system, it is still highly recommended not only for preventing engine corrosion but also for the environment benefit in which air pollution by H 2 S/SO 2 emission and impact on human health could be potentially reduced. (author)

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

Design of a dry cask storage system for spent LWR fuels: radiation protection, subcriticality, and heat removal aspects

Energy Technology Data Exchange (ETDEWEB)

Yavuz, U. [Turkish Atomic Energy Authority, Ankara (Turkey). Nuclear Safety Dept.; Zabunoolu, O.H. [Hacettepe Univ., Ankara (Turkey). Dept. of Nuclear Engineering

2006-08-15

Spent nuclear fuel resulting from reactor operation must be safely stored and managed prior to reprocessing and/or final disposal of high-level waste. Any spent fuel storage system must provide for safe receipt, handling, retrieval, and storage of spent fuel. In order to achieve the safe storage, the design should primarily provide for radiation protection, subcriticality of spent fuel, and removal of spent fuel residual heat. This article is focused on the design of a metal-shielded dry-cask storage system, which will host spent LWR fuels burned to 33 000, 45 000, and 55 000 MWd/t U and cooled for 5 or 10 years after discharge from reactor. The storage system is analyzed by taking into account radiation protection, subcriticality, and heat-removal aspects; and appropriate designs, in accordance with the international standards. (orig.)

Sixty Percent Conceptual Design Report: Enterprise Accountability System for Classified Removable Electronic Media

Energy Technology Data Exchange (ETDEWEB)

B. Gardiner; L.Graton; J.Longo; T.Marks, Jr.; B.Martinez; R. Strittmatter; C.Woods; J. Joshua

2003-05-03

Classified removable electronic media (CREM) are tracked in several different ways at the Laboratory. To ensure greater security for CREM, we are creating a single, Laboratory-wide system to track CREM. We are researching technology that can be used to electronically tag and detect CREM, designing a database to track the movement of CREM, and planning to test the system at several locations around the Laboratory. We focus on affixing ''smart tags'' to items we want to track and installing gates at pedestrian portals to detect the entry or exit of tagged items. By means of an enterprise database, the system will track the entry and exit of tagged items into and from CREM storage vaults, vault-type rooms, access corridors, or boundaries of secure areas, as well as the identity of the person carrying an item. We are considering several options for tracking items that can give greater security, but at greater expense.

Effects of advanced treatment systems on the removal of antibiotic resistance genes in wastewater treatment plants from Hangzhou, China.

Science.gov (United States)

Chen, Hong; Zhang, Mingmei

2013-08-06

This study aimed at quantifying the concentration and removal of antibiotic resistance genes (ARGs) in three municipal wastewater treatment plants (WWTPs) employing different advanced treatment systems [biological aerated filter, constructed wetland, and ultraviolet (UV) disinfection]. The concentrations of tetM, tetO, tetQ, tetW, sulI, sulII, intI1, and 16S rDNA genes were examined in wastewater and biosolid samples. In municipal WWTPs, ARG reductions of 1-3 orders of magnitude were observed, and no difference was found among the three municipal WWTPs with different treatment processes (p > 0.05). In advanced treatment systems, 1-3 orders of magnitude of reductions in ARGs were observed in constructed wetlands, 0.6-1.2 orders of magnitude of reductions in ARGs were observed in the biological aerated filter, but no apparent decrease by UV disinfection was observed. A significant difference was found between constructed wetlands and biological filter (p removal of ARGs and 16S rDNA genes (R(2) = 0.391-0.866; p removal values with WWTP (p > 0.05) but also have the advantage in ARG relative abundance removal, and it should be given priority to be an advanced treatment system for further ARG attenuation from WWTP.

Nitrogen removal kinetics in the treatment of landfill leachate by SBR systems

International Nuclear Information System (INIS)

Andreottola, G.; Foladori, P.; Ragazzi, M.

1998-01-01

In this study, laboratory-scale experiments were conducted applying the SBR activated sludge process to leachate from an old MSW landfill operating for 7 years. Due to the fact that old leachate is characterized with a high concentration of ammonia (approximately 1500 mgN/1) and low availability of readily biodegradable organic matter (BOD 5 /COD,06), the aim was to examine the nitrogen removal process and to compare the efficiency of one-stage and two stage systems operating at temperature of 20 C and 12 C. The second alternative SBR configuration is based on the coupling of two SBR reactors: the first one specialized in nitrification and the second one in post-denitrification, with external carbon source addition. By the efficient removal of nitrogen, an on-site pretreatment of leachate allows to comply with the limits required for discharging into sewers or into municipal wastewater treatment plant [it

Radiation-Induced Grafting for the Synthesis of Adsorbents for Phosphate and Chromate Removal from Aqueous Systems

Energy Technology Data Exchange (ETDEWEB)

Kavakli, P A; Kavakli, C; Guven, O [Department of Chemistry, Hacettepe University, Beytepe, 06800, Ankara (Turkey)

2012-09-15

Nonwoven fabrics made of PE coated PP fibres were irradiated by accelerated electrons in inert atmospheres for grafting of two different monomers, glycidyl methacrylate and dimethylaminoethyl methacrylate. Grafting conditions were optimized by a systematic investigation of the effects of absorbed dose, monomer concentration, grafting reaction temperature and duration. 150% grafted copolymers were later modified by protonation and quaternization of poly(dimethylaminoethyl methacrylate) chains and by Cu(II) loading of dipyridyl amine modified poly(glycidyl methacrylate) graft chains. The PE/PP based adsorbents thus prepared were used for their suitability of removing phosphate and chromate ions from aqueous systems. Adsorption/removal studies were carried out in both batch and continuous flow type systems. The selectivity of adsorption of phosphate ions in the presence of other competing anions were also checked showing the enhanced selectivity for phosphate ions. (author)

Hair and bare skin discrimination for laser-assisted hair removal systems.

Science.gov (United States)

Cayir, Sercan; Yetik, Imam Samil

2017-07-01

Laser-assisted hair removal devices aim to remove body hair permanently. In most cases, these devices irradiate the whole area of the skin with a homogenous power density. Thus, a significant portion of the skin, where hair is not present, is burnt unnecessarily causing health risks. Therefore, methods that can distinguish hair regions automatically would be very helpful avoiding these unnecessary applications of laser. This study proposes a new system of algorithms to detect hair regions with the help of a digital camera. Unlike previous limited number of studies, our methods are very fast allowing for real-time application. Proposed methods are based on certain features derived from histograms of hair and skin regions. We compare our algorithm with competing methods in terms of localization performance and computation time and show that a much faster real-time accurate localization of hair regions is possible with the proposed method. Our results show that the algorithm we have developed is extremely fast (around 45 milliseconds) allowing for real-time application with high accuracy hair localization ( 96.48 %).

Experience on the removal of impurities from liquid metal systems by cold-trapping

Energy Technology Data Exchange (ETDEWEB)

Bray, J. A.

1963-10-15

Experience in impurity removal by cold-trapping, which was obtained on DFR and its associated liquid metal rigs, is reviewed. The development of the present DFR cold-trapping system is outlined, and the operation of the additional pumped loops, which were required in order to control the reactor impurity levels, are described. Operation of the liquid metal rigs ancillary to the reactor project is discussed with particular reference to the control of impurity levels. (auth)

Removal of mercury vapor from ambient air of dental clinics using an air cleaning system based on silver nanoparticles

Directory of Open Access Journals (Sweden)

Chiman Saeidi

2015-06-01

Full Text Available Background & objective: Mercury is a toxic and bio-accumulative pollutant that has adverse effects on environmental and human health. There have been a number of attempts to regulate mercury emissions tothe atmosphere. Silver nanoparticles are a number of materials that have highly potential to absorb mercury and formation of mercury amalgam.The aim of this study is removal of mercury vapors in the dental clinic using a n a ir cleaning system based on silver nanoparticles. Methods: In this study, silver nanoparticles coated on the bed of foam and chemical and structural properties were determined using a number of methods such as UV-VIS-NIR spectroscopy and Scanning Electron Microscope (SEM connected the X-ray Emission Spectroscopy Energy (EDS. The a ir cleaning system efficiency to remove of the mercury vapor in simulated conditions in the laboratory and real conditions in the dental clinicwere measured by Cold Vapor Atomic Absorption Spectroscopy (CVAAS. Results: The images of SEM, showed that average sizeof silver nanoparticles in colloidal solution was ∼ 30nm and distribution of silver nanoparticles coated on foam was good. EDS spectrum confirmed associated the presence of silver nanoparticles coated on foam. The significantly difference observed between the concentration of mercury vapor in the off state (9.43 ± 0.342 μg.m-3 and on state (0.51 ± 0.031μg.m-3 of the a ir cleaning system. The mercury vapor removal efficiencyof the a ir cleaning system was calculated 95%. Conclusion : The air cleaning system based on foam coated by silver nanoparticles, undertaken to provide the advantages such as use facilitating, highly efficient operational capacity and cost effective, have highly sufficiency to remove mercury vapor from dental clinics.

Laboratory tests in support of the MSRE reactive gas removal system

International Nuclear Information System (INIS)

Rudolph, J.C.; Del Cul, G.D.; Caja, J.; Toth, L.M.; Williams, D.F.; Thomas, K.S.; Clark, D.E.

1997-07-01

The Molten Salt Reactor Experiment (MSRE) at Oak Ridge National Laboratory has been shut down since December 1969, at which time the molten salt mixture of LiF-BeF 2 -ZrF 4 - 233 UF 4 (64.5-30.3-5.0-0.13 mol%) was transferred to fuel salt drain tanks for storage. In the late 1980s, increased radiation in one of the gas lines from the drain tank was attributed to 233 UF 6 . In 1994 two gas samples were withdraw (from a gas line in the Vent House connecting to the drain tanks) and analyzed. Surprisingly, 350 mm Hg of F 2 , 70 mm Hg of UF 6 , and smaller amounts of other gases were found in both of the samples. To remote this gas from above the drain tanks and all of the associated piping, the reactive gas removal system (RGRS) was designed. This report details the laboratory testing of the RGRS, using natural uranium, prior to its implementation at the MSRE facility. The testing was performed to ensure that the equipment functioned properly and was sufficient to perform the task while minimizing exposure to personnel. In addition, the laboratory work provided the research and development effort necessary to maximize the performance of the system. Throughout this work technicians and staff who were to be involved in RGRS operation at the MSRE site worked directly with the research staff in completing the laboratory testing phase. Consequently, at the end of the laboratory work, the personnel who were to be involved in the actual operations had acquired all of the training and experience necessary to continue with the process of reactive gas removal

Removal of bulk contaminants from radioactive waste water at Bruce A using a clay based flocculent system

International Nuclear Information System (INIS)

Davloor, R.; Harper, B.

2011-01-01

Bruce Power's Bruce Nuclear Generating Station 'A', located on Lake Huron, has a treatment system that processes all aqueous radioactive waste water originating from the station. This Active Liquid Waste Treatment System (ALWTS) consists of collection tanks for the collection of radioactive waste water, a Pre-Treatment System (PTS) for the removal of bulk contaminants and suspended solids, a Reverse Osmosis System (ROS) to remove dissolved solids, an Evaporation and Solidification System (ESS) to concentrate and immobilize solids contained in concentrated waste streams from the ROS, and discharge tanks for the dispersal of the treated water. The ALWTS has been in continuous service since 1999 and is used to treat approximately 100,000 litres of Active Liquid Waste (ALW) each day. With the exception of tritium, it discharges waste water containing near zero concentrations of radioactive and conventional contaminants to the lake. The original design of the Bruce A ALWTS used a Backwashable Filtration System (BFS) to provide solids free water to the ROS, as measured by the Silt Density Index (SDI). During commissioning, the BFS was not successful in backwashing the solids from the filter elements. For approximately one year, a temporary solution was implemented using a Disposable Filtration System (DFS). A cationic polymer was added upstream of the DFS to agglomerate the solids. The system proved to be highly unreliable. It was difficult to agglomerate solids in the waste stream containing high amounts of detergent. As a result, DFS consumption was high and very costly. The SDI specification for the RO membrane was not always met, resulting in a quick decline of performance of the first stage ROS membranes in the treatment process. In addition, the excess cationic polymer in the RO feed caused the membranes to become fouled. In-house station staff, together with personnel from Colloid Environmental Technologies (CETCO) Company, worked to develop and

Removal of bulk contaminants from radioactive waste water at Bruce A using a clay based flocculent system

Energy Technology Data Exchange (ETDEWEB)

Davloor, R.; Harper, B. [Bruce Power, Tiverton, ON (Canada)

2011-07-01

Bruce Power's Bruce Nuclear Generating Station 'A', located on Lake Huron, has a treatment system that processes all aqueous radioactive waste water originating from the station. This Active Liquid Waste Treatment System (ALWTS) consists of collection tanks for the collection of radioactive waste water, a Pre-Treatment System (PTS) for the removal of bulk contaminants and suspended solids, a Reverse Osmosis System (ROS) to remove dissolved solids, an Evaporation and Solidification System (ESS) to concentrate and immobilize solids contained in concentrated waste streams from the ROS, and discharge tanks for the dispersal of the treated water. The ALWTS has been in continuous service since 1999 and is used to treat approximately 100,000 litres of Active Liquid Waste (ALW) each day. With the exception of tritium, it discharges waste water containing near zero concentrations of radioactive and conventional contaminants to the lake. The original design of the Bruce A ALWTS used a Backwashable Filtration System (BFS) to provide solids free water to the ROS, as measured by the Silt Density Index (SDI). During commissioning, the BFS was not successful in backwashing the solids from the filter elements. For approximately one year, a temporary solution was implemented using a Disposable Filtration System (DFS). A cationic polymer was added upstream of the DFS to agglomerate the solids. The system proved to be highly unreliable. It was difficult to agglomerate solids in the waste stream containing high amounts of detergent. As a result, DFS consumption was high and very costly. The SDI specification for the RO membrane was not always met, resulting in a quick decline of performance of the first stage ROS membranes in the treatment process. In addition, the excess cationic polymer in the RO feed caused the membranes to become fouled. In-house station staff, together with personnel from Colloid Environmental Technologies (CETCO) Company, worked to develop and

Removal Efficiency of Nitrogen, Phosphorus and Heavy Metal by Intermittent Cycle Extended Aeration System from Municipal Wastewater (Yazd-ICEAS

Directory of Open Access Journals (Sweden)

Seyed Vahid Ghelmani

2016-09-01

Conclusion: The high removal efficiency of BOD5, TKN, and NH4+ showed that this advanced SBR system had an appropriate efficiency for nitrification. Phosphorus removal (TP had a lower efficiency than those of NH4+ and TKN, but it was within the environmental standard limits. On the other hand, in the advanced SBR the removal efficiency of heavy metals for Cd was not within the standard limits.

Copper (II) Removal In Anaerobic Continuous Column Reactor System By Using Sulfate Reducing Bacteria

Science.gov (United States)

Bilgin, A.; Jaffe, P. R.

2017-12-01

Copper is an essential element for the synthesis of the number of electrons carrying proteins and the enzymes. However, it has a high level of toxicity. In this study; it is aimed to treat copper heavy metal in anaerobic environment by using anaerobic continuous column reactor. Sulfate reducing bacteria culture was obtained in anaerobic medium using enrichment culture method. The column reactor experiments were carried out with bacterial culture obtained from soil by culture enrichment method. The system is operated with continuous feeding and as parallel. In the first rector, only sand was used as packing material. The first column reactor was only fed with the bacteria nutrient media. The same solution was passed through the second reactor, and copper solution removal was investigated by continuously feeding 15-600 mg/L of copper solution at the feeding inlet in the second reactor. When the experiment was carried out by adding the 10 mg/L of initial copper concentration, copper removal in the rate of 45-75% was obtained. In order to determine the use of carbon source during copper removal of mixed bacterial cultures in anaerobic conditions, total organic carbon TOC analysis was used to calculate the change in carbon content, and it was calculated to be between 28% and 75%. When the amount of sulphate is examined, it was observed that it changed between 28-46%. During the copper removal, the amounts of sulphate and carbon moles were equalized and more sulfate was added by changing the nutrient media in order to determine the consumption of sulphate or carbon. Accordingly, when the concentration of added sulphate is increased, it is calculated that between 35-57% of sulphate is spent. In this system, copper concentration of up to 15-600 mg / L were studied.

Development of a ventilation system to remove odors and dust in a large indoor space; Daikukan no shuki funjin jokyo kanki system no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Kadoya, M.; Moteki, M.; Tatsumi, T.; Enokida, D.; Miyagi, H.; Maruoka, T. [Okumura Corp., Osaka (Japan)

1997-07-31

The ventilation system for removing odor and dust was studied for the waste stock yard and working yard of a segregated waste stock facility of 17,280m{sup 3} in air volume. The developed ventilation system includes the air curtain and wind shield plate between the waste stock yard and working yard. Air curtain flow is formed by jet stream from nozzles installed at certain constant intervals. This system was developed through air flow analysis, model experiment, and field measurement. The air flow analysis pointed out that reverse flow derived from a part of air flow contaminates the working yard, however, this system can exclude such reverse flow and reduce CO2 concentration to 1/80. The model experiment result showed that this system can reduce CO2 concentration to 1/18. The field measurement confirmed the air curtain effect by smoke visualization. In the measurement of dummy dust concentration generated for 15min, this system was possible to reduce the concentration to 1/7. 4 refs., 18 figs., 6 tabs.

A concept of passive safety pressurized water reactor system with inherent matching nature of core heat generation and heat removal

International Nuclear Information System (INIS)

Murao, Yoshio; Araya, Fumimasa; Iwamura, Takamichi; Okumura, Keisuke

1995-01-01

The reduction of manpower in operation and maintenance by simplification of the system are essential to improve the safety and the economy of future light water reactors. At the Japan Atomic Energy Research Institute (JAERI), a concept of a simplified passive safety reactor system JPSR was developed for this purpose and in the concept minimization of developing work and conservation of scale-up capability in design were considered. The inherent matching nature of core heat generation and heat removal rate is introduced by the core with high reactivity coefficient for moderator density and low reactivity coefficient for fuel temperature (Doppler effect) and once-through steam generators (SGs). This nature makes the nuclear steam supply system physically-slave for the steam and energy conversion system by controlling feed water mass flow rate. The nature can be obtained by eliminating chemical shim and adopting in-vessel control rod drive mechanism (CRDM) units and a low power density core. In order to simplify the system, a large pressurizer, canned pumps, passive residual heat removal systems with air coolers as a final heat sink and passive coolant injection system are adopted and the functions of volume and boron concentration control and seal water supply are eliminated from the chemical and volume control system (CVCS). The emergency diesel generators and auxiliary component cooling system of 'safety class' for transferring heat to sea water as a final heat sink in emergency are also eliminated. All of systems are built in the containment except for the air coolers of the passive residual heat removal system. The analysis of the system revealed that the primary coolant expansion in 100% load reduction in 60 s can be mitigated in the pressurizer without actuating the pressure relief valves and the pressure in 50% load change in 30 s does not exceed the maximum allowable pressure in accidental conditions in regardless of pressure regulation. (author)

Removal of Retained Adherent Placental Remnants Using the Hysteroscopy Endo-Operative System.

Science.gov (United States)

Zhu, Ke-An; Huang, Huan; Xue, Min; Subedi, Jigyasa; Jamail, Grace; Zhao, Weidong; Xu, Dabao; Xiao, Songshu

2016-01-01

Removal of retained adherent placental remnants (RAPRs) may be challenging using traditional 5Fr or 7Fr hysteroscopic grasping forceps because they are very small. This is particularly true when the retained placental remnant is large. This video demonstrates the advantages of using the Hysteroscopy Endo-Operative System (HEOS), a specially designed operative hysteroscope with a 13Fr working channel, to remove retained placental remnants. Step-by-step explanation of the technique using videos and pictures (educative video) (Canadian Task Force Classification III). Third Xiangya Hospital of Central South University, Hunan, China. A 32-year-old woman was diagnosed with RAPRs 5 weeks after the evacuation of retained placenta after a spontaneous abortion at 16 weeks' gestation. Gynecologic examination revealed an anterior 8-week uterus and no tenderness. Serum β-human chorionic gonadotropin was 150 mIU/L. Sonography revealed an irregular intrauterine mass, 3.5 cm × 3.5 cm × 3 cm in size. Removal of RAPRs using HEOS (Sopro-comeg Company, Bordeaux, France). The operation time was only 12 minutes. The RAPRs were removed completely and quickly in 1 procedure with no complications. The serum β-human chorionic gonadotropin titer normalized 1 week after the procedure. This study was approved by the institutional review board of the Third Xiangya Hospital of Central South University. When indicated, removal of RAPRs using HEOS is safe and simple because of its large and strong cold forceps. Additionally, it avoids electrical and thermal injury to the endometrium, which is particularly important in a population that wants to preserve fertility. Copyright © 2016 AAGL. Published by Elsevier Inc. All rights reserved.

Reliability analyses to detect weak points in secondary-side residual heat removal systems of KWU PWR plants

International Nuclear Information System (INIS)

Schilling, R.

1983-01-01

Requirements made by Federal German licensing authorities called for the analysis of the secondary-side residual heat removal systems of new PWR plants with regard to availability, possible weak points and the balanced nature of the overall system for different incident sequences. Following a description of the generic concept and the process and safety-related systems for steam generator feed and main steam discharge, the reliability of the latter is analyzed for the small break LOCA and emergency power mode incidents, weak points in the process systems identified, remedial measures of a system-specific and test-strategic nature presented and their contribution to improving system availability quantified. A comparison with the results of the German Risk Study on Nuclear Power Plants (GRS) shows a distinct reduction in core meltdown frequency. (orig.)

AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT XIV, I--MAINTAINING THE AIR SYSTEM, CUMMINS DIESEL ENGINE, II--UNIT REMOVAL--TRANSMISSION.

Science.gov (United States)

Human Engineering Inst., Cleveland, OH.

THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATING PRINCIPLES AND MAINTENANCE OF THE DIESEL ENGINE AIR SYSTEM AND THE PROCEDURES FOR TRANSMISSION REMOVAL. TOPICS ARE (1) DEFINITION OF TERMS RELATED TO THE DIESEL AIR SYSTEM, (2) PRNCIPLES OF DIESEL AIR COMPRESSORS, (3) PRINCIPLES OF AIR STARTING MOTORS, (4)…

Removal of traces of toluene and p-xylene in indoor air using biofiltration and a hybrid system (biofiltration + adsorption).

Science.gov (United States)

Luengas, Angela Tatiana; Hort, Cécile; Platel, Vincent; Elias, Ana; Barona, Astrid; Moynault, Laurent

2017-04-01

Biofiltration technology and the hybrid system combining biofiltration and adsorption (onto activated carbon) were compared as possible methods to toluene and p-xylene at parts per million concentration levels (2-45 and 1-33 ppb, respectively). An organic material was used as packing material for the biofiltration process. Even at low empty bed residence times (EBRTs) and concentrations, toluene removal efficiency reached 100% and p-xylene showed an increasing trend on their removal efficiency over the time using biofiltration. The assessment of by-products and particle generation by the biofilter and the hybrid system were taken into account. Acetone and acetic acid were identified as by-products of the biofilter. Particle emissions in the range of 0.03 to 10 μm were recorded for both systems.

75 FR 29217 - Office of the Attorney General; Certification Process for State Capital Counsel Systems; Removal...

Science.gov (United States)

2010-05-25

... Office of the Attorney General; Certification Process for State Capital Counsel Systems; Removal of Final Rule AGENCY: Office of the Attorney General, Department of Justice. ACTION: Notice of proposed... the Attorney General has certified ``that [the] State has established a mechanism for providing...

ETV REPORT: REMOVAL OF CHEMICAL CONTAMINANTS IN DRINKING WATER — PALL/KINETICO PUREFECTA DRINKING WATER TREATMENT SYSTEM

Science.gov (United States)

The Pall/Kinetico Purefecta™ POU drinking water treatment system was tested for removal of aldicarb, benzene, cadmium, carbofuran, cesium, chloroform, dichlorvos, dicrotophos, fenamiphos, mercury, mevinphos, oxamyl, strontium, and strychnine. The Purefecta™ employs several compon...

Investigation and optimization of the novel UASB-MFC integrated system for sulfate removal and bioelectricity generation using the response surface methodology (RSM).

Science.gov (United States)

Zhang, Baogang; Zhang, Jing; Yang, Qi; Feng, Chuanping; Zhu, Yuling; Ye, Zhengfang; Ni, Jinren

2012-11-01

COD/sulfate ratio and hydraulic residence time (HRT), both of which influence sulfate loadings jointly, are recognized as the most two important affecting factors for sulfate removal and bioelectricity generation in the novel up-flow anaerobic sludge blanket reactor-microbial fuel cell (UASB-MFC) integrated system. The response surface methodology (RSM) was employed for the optimization of this system and the optimum condition with COD/sulfate ratio of 2.3 and HRT of 54.3h was obtained with the target of maximizing the power output. In terms of maximizing the total sulfate removal efficiency, the obtained optimum condition was COD/sulfate ratio of 3.7 and HRT of 55.6h. Experimental results indicated the undistorted simulation and reliable optimized results. These demonstrated that RSM was effective to evaluate and optimize the UASB-MFC system for sulfate removal and energy recovery, providing a promising guide to further improvement of the system for potential applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

Vegetated Treatment Systems for Removing Contaminants Associated with Surface Water Toxicity in Agriculture and Urban Runoff.

Science.gov (United States)

Anderson, Brian S; Phillips, Bryn M; Voorhees, Jennifer P; Cahn, Michael

2017-05-15

Urban stormwater and agriculture irrigation runoff contain a complex mixture of contaminants that are often toxic to adjacent receiving waters. Runoff may be treated with simple systems designed to promote sorption of contaminants to vegetation and soils and promote infiltration. Two example systems are described: a bioswale treatment system for urban stormwater treatment, and a vegetated drainage ditch for treating agriculture irrigation runoff. Both have similar attributes that reduce contaminant loading in runoff: vegetation that results in sorption of the contaminants to the soil and plant surfaces, and water infiltration. These systems may also include the integration of granulated activated carbon as a polishing step to remove residual contaminants. Implementation of these systems in agriculture and urban watersheds requires system monitoring to verify treatment efficacy. This includes chemical monitoring for specific contaminants responsible for toxicity. The current paper emphasizes monitoring of current use pesticides since these are responsible for surface water toxicity to aquatic invertebrates.

Passive afterheat removal in the HTGR with the liner cooling system as a heat sink

International Nuclear Information System (INIS)

Rehm, W.; Jahn, W.; Verfondern, K.

1984-09-01

The report deals with the transients of temperature and system pressure and the fission product behaviour in the primary circuit of an HTGR during passive afterheat removal, where the liner cooling system of the PCRV serves as a heat sink. The analysis has been made for the PNP-500-reactor representing nuclear plants with medium thermal power. The investigations show that the liner cooling system is able to control a core heatup. High temperature loads are encountered in the upper core region. In the case of a reactor under pressure the fuel elements and the primary circuit remain intact as the first and second barriers for fission products. In the case of a depressurized primary circuit the liner cooling system also keeps the PCRV at normal operating temperatures. The effects of a core heatup on component damage and release of fission products are thus limited. (orig.) [de

Implementation of New System for Oxygen Generation and Carbon Dioxide Removal =

Science.gov (United States)

Karavolos, Angelo Peter

This research effort develops an integrated system for CO2 removal and O2 production. A unique material, dodeca-tungsto-phosphoric acid (H3PO4W12O3; henceforth referred to as DTPA) is mixed with tetra-ethyl-ortho-silicate Si(OC2H 5)4 or TEOS. This mixture exhibits unique properties of heat absorption and high electrical conductivity. In the system described herein, the DTPA resides within a cross linked arrangement of TEOS. The DTPA furnishes a source of O2, while the TEOS furnishes structural support for the large DTPA crystals. In addition, the large amount of H2O within the crystal also adsorbs CO2. It can also be cross-linked with other polymers such as polycarbonate, for different applications and properties such as flexible textiles. A set of isolated bench experiments were designed to test CO2 adsorption, O2 production, heat production, and voltage production were conducted to test the hypothesis that DTPA can provide CO2 adsorption, O2 generation, heat generation and electrical generation. Five experiments with this apparatus were conducted: (1) a mass balance experiment; (2) an X-ray diffraction experiment; (3) a photo spectroscopic experiment; (4) a calorimetric experiment; and (5) a dielectric experiment. Results illustrate that approximately 2880 grams of this material produces 576 grams of O2, and removes 1760 grams of CO2. The reaction also produces approximately 844 kJ/mole heat, and can supply 12.2 V potential over a period of 4.5 hours. The amount of unused material and the recycling ability suggests the usefulness of the technique to achieve between a 50-75% closed system. In addition, an experiment using 18O tracer demonstrated that approximately 20% of the O2 produced comes from processed CO2 adsorbed by the crystal, while the remaining 80% of the O2 produced comes from replaced O2 within the crystal itself. The device has multiple applications including environmental control and life support for aircraft cabins, space vehicle interiors

Design of CAREM-25 Residual Heat Removal System: Nuclear Safety Aspects

International Nuclear Information System (INIS)

Zanocco, Pablo; Gimenez, Marcelo; Schlamp, Miguel; Barrera, M.

2000-01-01

In this paper Carem-25 residual heat removal system (RHRS) design is analyzed from the nuclear safety point of view.The proposed RHRS is a condenser that transfers the heat to a pool located in the upper level of the containment.The RHRS design basis accident is a reactor loss of heat sink.The following requirements were settled to be verified: a) To remove 2 MW, for a primary circuit pressure of 12.25 MPa and a pool temperature of 100 0 C. b) No condenser tubes flooding, for a primary circuit pressure of 14 MPa and a pool temperature of 100 0 C. c) To reach hot shutdown in 48-hrs, that is to remove of 0.6 MW for a primary circuit pressure of 2.3 MPa and a pool temperature of 120 0 C.Heat transfer regimes inside and outside the condenser and flow patterns were analyzed.Steady state conditions for the above design conditions were modeled.The design requirements were verified taking into account heat transfer coefficients uncertainties and their propagation to the equipment elevation in the containment over the RPV, in order to minimize its elevation and its possible flooding.The resulting condenser tubes were 2 S CH 160 TP 347 SS, with a total area of 4 m 2 and a required minimum height of 6 m from the RPV water level to the condenser outlet headers

Alternatives Generation Analysis Long Length Contaminated Equipment Removal System Storage

International Nuclear Information System (INIS)

BOGER, R.M.

1999-01-01

Major pieces of Characterization sampling equipment are currently stored outdoors. This includes the Long Length Contaminated Equipment receiver trailer and transportation trailer. A decision is required to determine the preferred alternative for facilities to store and maintain this equipment. The Long Length Contaminated Equipment Removal System (LLCERS) consists of many tools, mechanisms, and controllers currently stored in various locations. Much of this equipment should be protected from the elements while being stored. Some of the LLCERS equipment should be protected with some kind of roof cover. This decision analysis is to determine the best alternative for weather protection for the large equipment requiring a cover. Additional details are included in Sections 2.0 and 5.0. Key assumptions used in this analysis are detailed in Section 3.2

Removal of triazine herbicides from freshwater systems using photosynthetic microorganisms

International Nuclear Information System (INIS)

Gonzalez-Barreiro, O.; Rioboo, C.; Herrero, C.; Cid, A.

2006-01-01

The uptake of the triazine herbicides, atrazine and terbutryn, was determined for two freshwater photosynthetic microorganisms, the green microalga Chlorella vulgaris and the cyanobacterium Synechococcus elongatus. An extremely rapid uptake of both pesticides was recorded, although uptake rate was lower for the cyanobacterium, mainly for atrazine. Other parameters related to the herbicide bioconcentration capacity of these microorganisms were also studied. Growth rate, biomass, and cell viability in cultures containing herbicide were clearly affected by herbicide uptake. Herbicide toxicity and microalgae sensitivity were used to determine the effectiveness of the bioconcentration process and the stability of herbicide removal. C. vulgaris showed higher bioconcentration capability for these two triazine herbicides than S. elongatus, especially with regard to terbutryn. This study supports the usefulness of such microorganisms, as a bioremediation technique in freshwater systems polluted with triazine herbicides

Removal of triazine herbicides from freshwater systems using photosynthetic microorganisms

Energy Technology Data Exchange (ETDEWEB)

Gonzalez-Barreiro, O. [Laboratorio de Microbiologia, Facultad de Ciencias, Universidad de A Coruna, Campus da Zapateira s/n. 15071 A Coruna (Spain); Rioboo, C. [Laboratorio de Microbiologia, Facultad de Ciencias, Universidad de A Coruna, Campus da Zapateira s/n. 15071 A Coruna (Spain); Herrero, C. [Laboratorio de Microbiologia, Facultad de Ciencias, Universidad de A Coruna, Campus da Zapateira s/n. 15071 A Coruna (Spain); Cid, A. [Laboratorio de Microbiologia, Facultad de Ciencias, Universidad de A Coruna, Campus da Zapateira s/n. 15071 A Coruna (Spain)]. E-mail: cid@udc.es

2006-11-15

The uptake of the triazine herbicides, atrazine and terbutryn, was determined for two freshwater photosynthetic microorganisms, the green microalga Chlorella vulgaris and the cyanobacterium Synechococcus elongatus. An extremely rapid uptake of both pesticides was recorded, although uptake rate was lower for the cyanobacterium, mainly for atrazine. Other parameters related to the herbicide bioconcentration capacity of these microorganisms were also studied. Growth rate, biomass, and cell viability in cultures containing herbicide were clearly affected by herbicide uptake. Herbicide toxicity and microalgae sensitivity were used to determine the effectiveness of the bioconcentration process and the stability of herbicide removal. C. vulgaris showed higher bioconcentration capability for these two triazine herbicides than S. elongatus, especially with regard to terbutryn. This study supports the usefulness of such microorganisms, as a bioremediation technique in freshwater systems polluted with triazine herbicides.

Design and modeling of an advanced marine machinery system including waste heat recovery and removal of sulphur oxides

DEFF Research Database (Denmark)

Frimann Nielsen, Rasmus; Haglind, Fredrik; Larsen, Ulrik

2013-01-01

-stroke diesel engine and a conventional waste heat recovery system. The results suggest that an organic Rankine cycle placed after the conventional waste heat recovery system is able to extract the sulphuric acid from the exhaust gas, while at the same time increase power generation from waste heat by 32...... consists of a two-stroke diesel engine, the wet sulphuric process for sulphur removal and an advanced waste heat recovery system including a conventional steam Rankine cycle and an organic Rankine cycle. The results are compared with those of a state-of-the-art machinery system featuring a two...

Nitrous oxide production by lithotrophic ammonia-oxidizing bacteria and implications for engineered nitrogen-removal systems.

Science.gov (United States)

Chandran, Kartik; Stein, Lisa Y; Klotz, Martin G; van Loosdrecht, Mark C M

2011-12-01

Chemolithoautotrophic AOB (ammonia-oxidizing bacteria) form a crucial component in microbial nitrogen cycling in both natural and engineered systems. Under specific conditions, including transitions from anoxic to oxic conditions and/or excessive ammonia loading, and the presence of high nitrite (NO₂⁻) concentrations, these bacteria are also documented to produce nitric oxide (NO) and nitrous oxide (N₂O) gases. Essentially, ammonia oxidation in the presence of non-limiting substrate concentrations (ammonia and O₂) is associated with N₂O production. An exceptional scenario that leads to such conditions is the periodical switch between anoxic and oxic conditions, which is rather common in engineered nitrogen-removal systems. In particular, the recovery from, rather than imposition of, anoxic conditions has been demonstrated to result in N₂O production. However, applied engineering perspectives, so far, have largely ignored the contribution of nitrification to N₂O emissions in greenhouse gas inventories from wastewater-treatment plants. Recent field-scale measurements have revealed that nitrification-related N₂O emissions are generally far higher than emissions assigned to heterotrophic denitrification. In the present paper, the metabolic pathways, which could potentially contribute to NO and N₂O production by AOB have been conceptually reconstructed under conditions especially relevant to engineered nitrogen-removal systems. Taken together, the reconstructed pathways, field- and laboratory-scale results suggest that engineering designs that achieve low effluent aqueous nitrogen concentrations also minimize gaseous nitrogen emissions.

Bimetallic Porous Iron (pFe) Materials for Remediation/Removal of Tc from Aqueous Systems

Energy Technology Data Exchange (ETDEWEB)

Li, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-09-29

Remediation of Tc remains an unresolved challenge at SRS and other DOE sites. The objective of this project was to develop novel bimetallic porous iron (pFe) materials for Tc removal from aqueous systems. We showed that the pFe is much more effective in removing TcO₄ - (×30) and ReO₄ - (×8) from artificial groundwater than granular iron. Tc K-edge XANES spectroscopy indicated that Tc speciation on the pFe was 18% adsorbed TcO₄ -, 28% Tc(IV) in Tc dioxide and 54% Tc(IV) into the structure of Fe hydroxide. A variety of catalytic metal nanoparticles (i.e., Ni, Cu, Zn, Ag, Sn and Pd) were successfully deposited on the pFe using scalable chemical reduction methods. The Zn-pFe was outstanding among the six bimetallic pFe materials, with a capacity increase of >100% for TcO₄ - removal and of 50% for ReO₄ - removal, compared to the pFe. These results provide a highly applicable platform for solving critical DOE and industrial needs related to nuclear environmental stewardship and nuclear power production.

Removal of heavy metals from fly ash leachate using combined bioelectrochemical systems and electrolysis

International Nuclear Information System (INIS)

Tao, Hu-Chun; Lei, Tao; Shi, Gang; Sun, Xiao-Nan; Wei, Xue-Yan; Zhang, Li-Juan; Wu, Wei-Min

2014-01-01

Highlights: • Heavy metals removal from MSWI fly ash with BES and electrolysis was confirmed. • 98.5% of Cu(II), 95.4% of Zn(II) and 98.1% of Pb(II) removal were achieved in reactors. • BESs can remove some heavy metals in fly ash with energy saving. -- Abstract: Based on environmental and energetic analysis, a novel combined approach using bioelectrochemical systems (BES) followed by electrolysis reactors (ER) was tested for heavy metals removal from fly ash leachate, which contained high detectable levels of Zn, Pb and Cu according to X-ray diffraction analysis. Acetic acid was used as the fly ash leaching agent and tested under various leaching conditions. A favorable condition for the leaching process was identified to be liquid/solid ratio of 14:1 (w/w) and leaching duration 10 h at initial pH 1.0. It was confirmed that the removal of heavy metals from fly ash leachate with the combination of BESs and ER is feasible. The metal removal efficiency was achieved at 98.5%, 95.4% and 98.1% for Cu(II), Zn(II), and Pb(II), respectively. Results of scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) indicated that Cu(II) was reduced and recovered mainly as metal Cu on cathodes related to power production, while Zn(II) and Pb(II) were not spontaneously reduced in BESs without applied voltage and basically electrolyzed in the electrolysis reactors

75 FR 71353 - Office of the Attorney General; Certification Process for State Capital Counsel Systems; Removal...

Science.gov (United States)

2010-11-23

... the Attorney General; Certification Process for State Capital Counsel Systems; Removal of Final Rule... only if the Attorney General has certified ``that [the] State has established a mechanism for providing... State to qualify for the special habeas procedures, the Attorney General must determine that ``the State...

Removal of inorganic As5+ from a small drinking water system

Directory of Open Access Journals (Sweden)

MARJANA SIMONIC

2009-01-01

Full Text Available The drinking water from a small drinking water system contained arsenic in a concentration of about 50 μg/L. Chemical analyses showed that the pentavalent form of arsenic was present. Since the MCL value is 10 μg/L, it was necessary to implement a technological treatment to make the water suitable for drinking. In order to do so, two technologies were suggested: activated alumina and a-FeOOH (TehnoArz, TA adsorption media. Experiments using both adsorption media were performed on a laboratory scale. It was possible to remove arsenic to below 1 μg/L. The maximal adsorption capacity was found to be 12.7 mg of As5+ per gram of a-FeOOH. Moreover, all the important physico–chemical parameters of the water remained practically unchanged after the treatment. Only a slight release of iron from the media was observed. The Fe–As bond was studied by means of chemical analysis and X-ray powder diffraction. Finally, in addition to showing the capability of arsenic removal by a-FeOOH, a comprehensive optimization of the technological parameters of the selected technology is provided.

Removal of polonium contamination by lead-bismuth eutectic in nuclear systems

International Nuclear Information System (INIS)

Miura, Terumitsu; Obara, Toru; Sekimoto, Hiroshi

2003-01-01

Lead-Bismuth eutectic (LBE) is considered as a promising candidate of the coolant of liquid metal cooled fast reactor, and the coolant and/or target of accelerator driven system. LBE has various good characters for coolant, but it has also some problems such as polonium production. It is necessary to take polonium contamination into consideration, when LBE is used as the coolant. In the present paper, the removal of contaminating polonium from material surface is studied. Baking method is investigated for polonium removal from contaminated quartz glass plate in vacuum. Before and after baking, the mass of the contaminants on the surface and alpha particle counts from contaminated surface is measured. When the contaminated quartz glass plates are baked at more than 400degC for a few minutes, alpha particle counts from the surface decreases by more than 99.7%, and the mass of contaminants decreases by more than 50%. When the baking was performed at 300degC for 15 minutes and more, alpha particle count decreases by more than 80%, and the mass decreases in little. When, the baking temperature is lower than 200degC, alpha particle counts and mass do not decrease. (author)

Centralized Duplicate Removal Video Storage System with Privacy Preservation in IoT

Directory of Open Access Journals (Sweden)

Hongyang Yan

2018-06-01

Full Text Available In recent years, the Internet of Things (IoT has found wide application and attracted much attention. Since most of the end-terminals in IoT have limited capabilities for storage and computing, it has become a trend to outsource the data from local to cloud computing. To further reduce the communication bandwidth and storage space, data deduplication has been widely adopted to eliminate the redundant data. However, since data collected in IoT are sensitive and closely related to users’ personal information, the privacy protection of users’ information becomes a challenge. As the channels, like the wireless channels between the terminals and the cloud servers in IoT, are public and the cloud servers are not fully trusted, data have to be encrypted before being uploaded to the cloud. However, encryption makes the performance of deduplication by the cloud server difficult because the ciphertext will be different even if the underlying plaintext is identical. In this paper, we build a centralized privacy-preserving duplicate removal storage system, which supports both file-level and block-level deduplication. In order to avoid the leakage of statistical information of data, Intel Software Guard Extensions (SGX technology is utilized to protect the deduplication process on the cloud server. The results of the experimental analysis demonstrate that the new scheme can significantly improve the deduplication efficiency and enhance the security. It is envisioned that the duplicated removal system with privacy preservation will be of great use in the centralized storage environment of IoT.

Centralized Duplicate Removal Video Storage System with Privacy Preservation in IoT.

Science.gov (United States)

Yan, Hongyang; Li, Xuan; Wang, Yu; Jia, Chunfu

2018-06-04

In recent years, the Internet of Things (IoT) has found wide application and attracted much attention. Since most of the end-terminals in IoT have limited capabilities for storage and computing, it has become a trend to outsource the data from local to cloud computing. To further reduce the communication bandwidth and storage space, data deduplication has been widely adopted to eliminate the redundant data. However, since data collected in IoT are sensitive and closely related to users' personal information, the privacy protection of users' information becomes a challenge. As the channels, like the wireless channels between the terminals and the cloud servers in IoT, are public and the cloud servers are not fully trusted, data have to be encrypted before being uploaded to the cloud. However, encryption makes the performance of deduplication by the cloud server difficult because the ciphertext will be different even if the underlying plaintext is identical. In this paper, we build a centralized privacy-preserving duplicate removal storage system, which supports both file-level and block-level deduplication. In order to avoid the leakage of statistical information of data, Intel Software Guard Extensions (SGX) technology is utilized to protect the deduplication process on the cloud server. The results of the experimental analysis demonstrate that the new scheme can significantly improve the deduplication efficiency and enhance the security. It is envisioned that the duplicated removal system with privacy preservation will be of great use in the centralized storage environment of IoT.

Process and system for removing sulfur from sulfur-containing gaseous streams

Science.gov (United States)

Basu, Arunabha; Meyer, Howard S.; Lynn, Scott; Leppin, Dennis; Wangerow, James R.

2012-08-14

A multi-stage UCSRP process and system for removal of sulfur from a gaseous stream in which the gaseous stream, which contains a first amount of H.sub.2S, is provided to a first stage UCSRP reactor vessel operating in an excess SO.sub.2 mode at a first amount of SO.sub.2, producing an effluent gas having a reduced amount of SO.sub.2, and in which the effluent gas is provided to a second stage UCSRP reactor vessel operating in an excess H.sub.2S mode, producing a product gas having an amount of H.sub.2S less than said first amount of H.sub.2S.

Development of a Next-Generation Membrane-Integrated Adsorption Processor for CO2 Removal and Compression for Closed-Loop Air Revitalization Systems

Science.gov (United States)

Mulloth, Lila; LeVan, Douglas

2002-01-01

The current CO2 removal technology of NASA is very energy intensive and contains many non-optimized subsystems. This paper discusses the concept of a next-generation, membrane integrated, adsorption processor for CO2 removal nd compression in closed-loop air revitalization systems. This processor will use many times less power than NASA's current CO2 removal technology and will be capable of maintaining a lower CO2 concentration in the cabin than that can be achieved by the existing CO2 removal systems. The compact, consolidated, configuration of gas dryer, CO2 separator, and CO2 compressor will allow continuous recycling of humid air in the cabin and supply of compressed CO2 to the reduction unit for oxygen recovery. The device has potential application to the International Space Station and future, long duration, transit, and planetary missions.

Effectiveness of the ProTaper Universal Retreatment™ system for removing a 10-year-old filling material.

Science.gov (United States)

Aguiar, C; Bernart, F; Lima, G; Câmara, A

2012-01-01

The aim of the present study was to evaluate the effectiveness of the ProTaper Universal Retreatment™ system and the manual technique for removing a 10-year-old filling material. Twenty mesiobuccal canals of mandibular first molars with curvature degrees ranging from 20° to 35° were instrumented by the Double-Flared Instrumentation Technique with the NitiFlex files. The root canals were dried with sterile paper points and filled with gutta-percha and a zinc oxide-eugenol-based sealer using a cold lateral condensation technique. Accesses to the cavities were temporarily sealed with Cavit. The teeth were embedded in gauze containing saline solution, which was renewed every 2 weeks, and were stored at 37 °C in 100% humidity for 10 years. Buccolingual and mesiodistal radiographs were taken to evaluate the quality of the root canal filling. The radiographs were mounted in slide frames to allow them to be evaluated by the three examiners, who were specialists in endodontics. Only the specimens in whom there was agreement between the three evaluators were included in the study. The specimens were divided into 2 groups with 10 root canals each, according to gutta-percha removal techniques: Group 1: ProTaper Universal Retreatment™ system; Group 2: Hedström and K-files. Buccolingual and mesiodistal radiographs were taken and evaluated by three examiners who determined the effectiveness of the removal of the filling material. The presence of material was measured according to a score scale. Data were analyzed statistically by Fisher's exact test at 5% significance level. There were no statistical differences between the two methods in the coronal (P=0.211), and middle (P=0.266) thirds, but there were statistical differences between the two methods in the apical third (P=0.038). Not one of the experimental techniques promoted complete removal of the filling materials. The manual technique with K-file and Hedström files achieved better results than the Pro

Removal of organic micropollutants in an artificial recharge system

Science.gov (United States)

Valhondo, C.; Nödler, K.; Köck-Schulmeyer, M.; Hernandez, M.; Licha, T.; Ayora, C.; Carrera, J.

2012-04-01

Emerging contaminants including pharmaceutically active compounds (PhACs), personal care products (PCPs) and pesticides are increasingly being identified in the environment. Emerging pollutants and their transformation products show low concentration in the environment (ng/L), but the effects of the mixtures and lifelong exposure to humans are currently unknown. Many of these contaminants are removed under aerobic conditions in water treatment plants. However, several pharmaceuticals and metabolites present in wastewater are not eliminated by conventional treatment processes. Several lab studies, however, show that the behaviour of many of these micropollutants is affected by the dominant redox conditions. However, data from field experiments are limited and sometimes contradictory. Artificial recharge is a widespread technology to increase the groundwater resources. In this study we propose a design to enhance the natural remediation potential of the aquifer with the installation of a reactive layer at the bottom of the infiltration pond. This layer is a mixture of compost, aquifer material, clay and iron oxide. This layer is intended to provide an extra amount of DOC to the recharge water and to promote biodegradation by means of the development of different redox zones along the travel path through the unsaturated zone and within the aquifer. Moreover, compost, clay and iron oxide of the layer are assumed to increase sorption surfaces for neutral, cationic and anionic compounds, respectively. The infiltration system is sited in Sant Vicenç dels Horts (Barcelona, Spain). It consists of a decantation pond, receiving raw water from the Llobregat River (highly affected from treatment plant effluents), and an infiltration pond (5600 m2). The infiltration rate is around 1 m3/m2/day. The system is equipped with a network of piezometers, suction cups and tensiometers. Infiltration periods have been performed before and after the installation of the reactive layer

REMOVAL OF ARSENIC IN DRINKING WATER: ARS CFU-50 APC ELECTROFLOCCULATION AND FILTRATION WATER TREATMENT SYSTEM

Science.gov (United States)

ETV testing of the ARS CFU-50 APC Electroflocculation and Filtration Water Treatment System (ARS CFU-50 APC) for arsenic removal was conducted at the Town of Bernalillo Well #3 site from April 18 through May 2, 2006. The source water was chlorinated groundwater from two supply w...

Planning of experimental removal of cadmium in finite bath system using the chocolate clay B as adsorbent

International Nuclear Information System (INIS)

Mota, J.D.; Rodrigues, M.G.F.; Lima, W.S.; Souza, R.S.

2012-01-01

The smectite clays are characterized by having a high cation exchange capacity and ability to remove metal ions. They have great industrial importance, for its abundance and low cost. The first part of this work was to characterize the clay called Chocolate B through the techniques of X-Ray Diffraction, X-Ray Spectroscopy and Energy Dispersive Physical Adsorption of Nitrogen. The second part of the work aims to evaluate the significance of the variables: pH and initial concentration on removal of cadmium in a batch system. In the experimental design used was a 2 2 factorial analysis with the addition at the central point, and evaluated the percentage of removal (Rem%) and removal capacity (EQF). XRD results corroborating the chemical analysis (EDX), characterized as a B Chocolate smectite clays. Statistical analysis showed a strong influence of variable pH on the removal of cadmium. (author)

Copper and zinc removal from roof runoff: from research to full-scale adsorber systems.

Science.gov (United States)

Steiner, M; Boller, M

2006-01-01

Large, uncoated copper and zinc roofs cause environmental problems if their runoff is infiltrated into the underground or discharged into receiving waters. Since source control is not always feasible, barrier systems for efficient copper and zinc removal are recommended in Switzerland. During the last few years, research carried out in order to test the performance of GIH-calcite adsorber filters as a barrier system. Adsorption and mass transport processes were assessed and described in a mathematical model. However, this model is not suitable for practical design, because it does not give explicit access to design parameters such as adsorber diameter and adsorber bed depth. Therefore, for e.g. engineers, an easy to use design guideline for GIH-calcite adsorber systems was developed, mainly based on the mathematical model. The core of this guideline is the design of the depth of the GIH-calcite adsorber layer. The depth is calculated by adding up the GIH depth for sorption equilibrium and the depth for the mass transfer zone (MTZ). Additionally, the arrangement of other adsorber system components such as particle separation and retention volume was considered in the guideline. Investigations of a full-scale adsorber confirm the successful application of this newly developed design guideline for the application of GIH-calcite adsorber systems in practice.

The role and control of sludge age in biological nutrient removal activated sludge systems.

Science.gov (United States)

Ekama, G A

2010-01-01

The sludge age is the most fundamental and important parameter in the design, operation and control of biological nutrient removal (BNR) activated sludge (AS) systems. Generally, the better the effluent and waste sludge quality required from the system, the longer the sludge age, the larger the biological reactor and the more wastewater characteristics need to be known. Controlling the reactor concentration does not control sludge age, only the mass of sludge in the system. When nitrification is a requirement, sludge age control becomes a requirement and the secondary settling tanks can no longer serve the dual purpose of clarifier and waste activated sludge thickeners. The easiest and most practical way to control sludge age is with hydraulic control by wasting a defined proportion of the reactor volume daily. In AS plants with reactor concentration control, nitrification fails first. With hydraulic control of sludge age, nitrification will not fail, rather the plant fails by shedding solids over the secondary settling tank effluent weirs.

Temporary storage or permanent removal? The division of nitrogen between biotic assimilation and denitrification in stormwater biofiltration systems.

Directory of Open Access Journals (Sweden)

Emily G I Payne

Full Text Available The long-term efficacy of stormwater treatment systems requires continuous pollutant removal without substantial re-release. Hence, the division of incoming pollutants between temporary and permanent removal pathways is fundamental. This is pertinent to nitrogen, a critical water body pollutant, which on a broad level may be assimilated by plants or microbes and temporarily stored, or transformed by bacteria to gaseous forms and permanently lost via denitrification. Biofiltration systems have demonstrated effective removal of nitrogen from urban stormwater runoff, but to date studies have been limited to a 'black-box' approach. The lack of understanding on internal nitrogen processes constrains future design and threatens the reliability of long-term system performance. While nitrogen processes have been thoroughly studied in other environments, including wastewater treatment wetlands, biofiltration systems differ fundamentally in design and the composition and hydrology of stormwater inflows, with intermittent inundation and prolonged dry periods. Two mesocosm experiments were conducted to investigate biofilter nitrogen processes using the stable isotope tracer 15NO3(- (nitrate over the course of one inflow event. The immediate partitioning of 15NO3(- between biotic assimilation and denitrification were investigated for a range of different inflow concentrations and plant species. Assimilation was the primary fate for NO3(- under typical stormwater concentrations (∼1-2 mg N/L, contributing an average 89-99% of 15NO3(- processing in biofilter columns containing the most effective plant species, while only 0-3% was denitrified and 0-8% remained in the pore water. Denitrification played a greater role for columns containing less effective species, processing up to 8% of 15NO3(-, and increased further with nitrate loading. This study uniquely applied isotope tracing to biofiltration systems and revealed the dominance of assimilation in stormwater

Developing an Integrated Model Framework for the Assessment of Sustainable Agricultural Residue Removal Limits for Bioenergy Systems

Energy Technology Data Exchange (ETDEWEB)

David Muth, Jr.; Jared Abodeely; Richard Nelson; Douglas McCorkle; Joshua Koch; Kenneth Bryden

2011-08-01

Agricultural residues have significant potential as a feedstock for bioenergy production, but removing these residues can have negative impacts on soil health. Models and datasets that can support decisions about sustainable agricultural residue removal are available; however, no tools currently exist capable of simultaneously addressing all environmental factors that can limit availability of residue. The VE-Suite model integration framework has been used to couple a set of environmental process models to support agricultural residue removal decisions. The RUSLE2, WEPS, and Soil Conditioning Index models have been integrated. A disparate set of databases providing the soils, climate, and management practice data required to run these models have also been integrated. The integrated system has been demonstrated for two example cases. First, an assessment using high spatial fidelity crop yield data has been run for a single farm. This analysis shows the significant variance in sustainably accessible residue across a single farm and crop year. A second example is an aggregate assessment of agricultural residues available in the state of Iowa. This implementation of the integrated systems model demonstrates the capability to run a vast range of scenarios required to represent a large geographic region.

Probabilistic reliability analyses to detect weak points in secondary-side residual heat removal systems of KWU PWR plants

International Nuclear Information System (INIS)

Schilling, R.

1984-01-01

Requirements made by Federal German licensing authorities called for the analysis of the second-side residual heat removal systems of new PWR plants with regard to availability, possible weak points and the balanced nature of the overall system for different incident sequences. Following a description of the generic concept and the process and safety-related systems for steam generator feed and main steam discharge, the reliability of the latter is analyzed for the small break LOCA and emergency power mode incidents, weak points in the process systems are identified, remedial measures of a system-specific and test-strategic nature are presented and their contribution to improving system availability is quantified. A comparison with the results of the German Risk Study on Nuclear Power Plants (GRS) shows a distinct reduction in core meltdown frequency. (orig.)

Whole house particle removal and clean air delivery rates for in-duct and portable ventilation systems.

Science.gov (United States)

Macintosh, David L; Myatt, Theodore A; Ludwig, Jerry F; Baker, Brian J; Suh, Helen H; Spengler, John D

2008-11-01

A novel method for determining whole house particle removal and clean air delivery rates attributable to central and portable ventilation/air cleaning systems is described. The method is used to characterize total and air-cleaner-specific particle removal rates during operation of four in-duct air cleaners and two portable air-cleaning devices in a fully instrumented test home. Operation of in-duct and portable air cleaners typically increased particle removal rates over the baseline rates determined in the absence of operating a central fan or an indoor air cleaner. Removal rates of 0.3- to 0.5-microm particles ranged from 1.5 hr(-1) during operation of an in-duct, 5-in. pleated media filter to 7.2 hr(-1) for an in-duct electrostatic air cleaner in comparison to a baseline rate of 0 hr(-1) when the air handler was operating without a filter. Removal rates for total particulate matter less than 2.5 microm in aerodynamic diameter (PM2.5) mass concentrations were 0.5 hr(-1) under baseline conditions, 0.5 hr(-1) during operation of three portable ionic air cleaners, 1 hr(-1) for an in-duct 1-in. media filter, 2.4 hr(-1) for a single high-efficiency particle arrestance (HEPA) portable air cleaner, 4.6 hr(-1) for an in-duct 5-in. media filter, 4.7 hr(-1) during operation of five portable HEPA filters, 6.1 hr(-1) for a conventional in-duct electronic air cleaner, and 7.5 hr(-1) for a high efficiency in-duct electrostatic air cleaner. Corresponding whole house clean air delivery rates for PM2.5 attributable to the air cleaner independent of losses within the central ventilation system ranged from 2 m3/min for the conventional media filter to 32 m3/min for the high efficiency in-duct electrostatic device. Except for the portable ionic air cleaner, the devices considered here increased particle removal indoors over baseline deposition rates.

Nuclear fuels technologies: Thermally induced gallium removal system (TIGRS), fiscal year 1998 research and development test plan

International Nuclear Information System (INIS)

Buksa, J.J.; Butt, D.P.; Chidester, K.; DeMuth, S.F.; Havrilla, G.J.; James, C.A.; Kolman, D.G.

1997-01-01

This document details the research and development (R and D) activities that will be conducted in Fiscal Year 1998 (FY98) by the Thermally Induced Gallium Removal System (TIGRS) team for the Department of Energy Office of Fissile Materials Disposition. This work is a continuation and extension of experimental activities that have been conducted in support of using weapons-derived plutonium in the fabrication of mixed-oxide (MOX) nuclear fuel for reactor-based plutonium disposition. The ultimate purpose of this work is to demonstrate adequate Thermally Induced Gallium Removal with a prototypic system. This Test Plan presents more than the FY98 R and D efforts in order to frame the Task in its entirety. To achieve the TIGRS Program objectives, R and D activities during the next two years will be focused on (1) process development leading to a prototypic TIGRS design, and (2) prototypic TIGRS design and testing leading to and including a prototypic demonstration of TIGRS operation. Both the process development and system testing efforts will consist of a series of surrogate-based cold tests and plutonium-based hot tests. Some of this testing has already occurred and will continue into FY99

Biogas recirculation for simultaneous calcium removal and biogas purification within an expanded granular sludge bed system treating leachate.

Science.gov (United States)

Luo, Jinghuan; Lu, Xueqin; Liu, Jianyong; Qian, Guangren; Lu, Yongsheng

2014-12-01

Biogas, generated from an expanded granular sludge bed (EGSB) reactor treating municipal solid waste (MSW) leachate, was recirculated for calcium removal from the leachate via a carbonation process with simultaneous biogas purification. Batch trials were performed to optimize the solution pH and imported biogas (CO2) for CaCO3 precipitation. With applicable pH of 10-11 obtained, continuous trials achieved final calcium concentrations of 181-375 mg/L (removal efficiencies≈92.8-96.5%) in the leachate and methane contents of 87.1-91.4% (purification efficiencies≈65.4-82.2%) in the biogas. Calcium-balance study indicates that 23-986 mg Ca/d was released from the bio-system under the carbonized condition where CaCO3 precipitating was moved outside the bioreactor, whereas 7918-9517 mg Ca/d was trapped into the system for the controlled one. These findings demonstrate that carbonation removal of calcium by biogas recirculation could be a promising alternative to pretreat calcium-rich MSW leachate and synergistically to improve methane content. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of recirculation in a three-tank pilot-scale system for pharmaceutical removal with powdered activated carbon.

Science.gov (United States)

Kårelid, Victor; Larsson, Gen; Björlenius, Berndt

2017-05-15

The removal of pharmaceutically active compounds by powdered activated carbon (PAC) in municipal wastewater is a promising solution to the problem of polluted recipient waters. Today, an efficient design strategy is however lacking with regard to high-level overall, and specific, substance removal in the large scale. The performance of PAC-based removal of pharmaceuticals was studied in pilot-scale with respect to the critical parameters; contact time and PAC dose using one PAC product selected by screening in bench-scale. The goal was a minimum of 95% removal of the pharmaceuticals present in the evaluated municipal wastewater. A set of 21 pharmaceuticals was selected from an initial 100 due to their high occurrence in the effluent water of two selected wastewater treatment plants (WWTPs) in Sweden, whereof candidates discussed for future EU regulation directives were included. By using recirculation of PAC over a treatment system using three sequential contact tanks, a combination of the benefits of powdered and granular carbon performance was achieved. The treatment system was designed so that recirculation could be introduced to any of the three tanks to investigate the effect of recirculation on the adsorption performance. This was compared to use of the setup, but without recirculation. A higher degree of pharmaceutical removal was achieved in all recirculation setups, both overall and with respect to specific substances, as compared to without recirculation. Recirculation was tested with nominal contact times of 30, 60 and 120 min and the goal of 95% removal could be achieved already at the shortest contact times at a PAC dose of 10-15 mg/L. In particular, the overall removal could be increased even to 97% and 99%, at 60 and 120 min, respectively, when the recirculation point was the first tank. Recirculation of PAC to either the first or the second contact tank proved to be comparable, while a slightly lower performance was observed with recirculation to

Cadmium analysis using field deployable nano-band electrode system and its removal using electrocoagulation

Science.gov (United States)

Guttula, Mallikarjuna Murthy

Cadmium (Cd) is an extremely toxic metal commonly found in industrial workplaces. Major industrial releases of Cd stem from waste streams, leaching of landfills, and from a variety of operations that involve cadmium or zinc. Particularly, cadmium can be released to drinking water from the corrosion of some galvanized plumbing and water main pipe materials. The United State Environmental Protection Agency (USEPA) has set the Maximum Contaminant Level (MCL) for cadmium at 5 ppb. Long term exposure of cadmium above the MCL results in kidney, liver, bone and blood damage. An accurate and rapid measurement of cadmium in the field remains a technical challenge. In this work, a relatively new method of a Nano-Band Electrode system using anodic stripping voltammetry was optimized by changing deposition potential, electrolyte, and plating time. We efficiently used Electrocoagulation remove cadmium from wastewater and obtained a removal efficiency of +/-99%. Removal mechanism of cadmium in electrocoagulation was also proposed with the help of X-ray Diffraction (XRD), Attenuated Total Reflection - Fourier Transform Infra Red Spectroscopy (ATR-FTIR), and Scanning Electron Microscopy and Energy Dispersive Spectrometer (SEM-EDS).

The steady-state modeling and optimization of a refrigeration system for high heat flux removal

International Nuclear Information System (INIS)

Zhou Rongliang; Zhang Tiejun; Catano, Juan; Wen, John T.; Michna, Gregory J.; Peles, Yoav; Jensen, Michael K.

2010-01-01

Steady-state modeling and optimization of a refrigeration system for high heat flux removal, such as electronics cooling, is studied. The refrigeration cycle proposed consists of multiple evaporators, liquid accumulator, compressor, condenser and expansion valves. To obtain more efficient heat transfer and higher critical heat flux (CHF), the evaporators operate with two-phase flow only. This unique operating condition necessitates the inclusion of a liquid accumulator with integrated heater for the safe operation of the compressor. Due to the projected incorporation of microchannels into the system to enhance the heat transfer in heat sinks, the momentum balance equation, rarely seen in previous vapor compression cycle heat exchangers modeling efforts, is utilized in addition to the mass and energy balance equations to capture the expected significant microchannel pressure drop witnessed in previous experimental investigations. Using the steady-state model developed, a parametric study is performed to study the effect of various external inputs on the system performance. The Pareto optimization is applied to find the optimal system operating conditions for given heat loads such that the system coefficient of performance (COP) is optimized while satisfying the CHF and other system operation constraints. Initial validation efforts show the good agreement between the experimental data and model predictions.

Development of evaluation method for heat removal design of dry storage facilities. pt. 1. Heat removal test on vault storage system of cross flow type

International Nuclear Information System (INIS)

Sakamoto, Kazuaki; Koga, Tomonari; Wataru, Masumi; Hattori, Yasuo

1997-01-01

The report describes the result of heat removal test of passive cooling vault storage system of cross flow type using 1/5 scale model. Based on a prospect of steady increase in the amount of spent fuel, it is needed to establish large capacity dry storage technologies for spent fuel. Air flow patterns, distributions of air temperature and velocity were measured, by which heat removal characteristics of the system were made clear. Air flow patterns in the storage module depended on the ratio of the buoyant force to the inertial force; the former generated by the difference of air temperatures and the height of the storage module, the latter by the difference of air densities between the outlet of the storage module and ambience and the height of the chimney of the storage facility. A simple method to estimate air flow patterns in the storage module was suggested, where Ri(Richardson) number was applied to represent the ratio. Moreover, heat transfer coefficient from a model of storage tube to cooling air was evaluated, and it was concluded that the generalized expression of heat transfer coefficient for common heat exchangers could be applied to the vault storage system of cross flow type, in which dozens of storage tubes were placed in a storage module. (author)

Including Life Cycle Assessment for decision-making in controlling wastewater nutrient removal systems

DEFF Research Database (Denmark)

Corominas, Lluís; Larsen, Henrik Fred; Flores-Alsina, Xavier

2013-01-01

This paper focuses on the use of Life Cycle Assessment (LCA) to evaluate the performance of seventeen control strategies in wastewater treatment plants (WWTPs). It tackles the importance of using site-specific factors for nutrient enrichment when decision-makers have to select best operating....../or energy savings present an environmental benefit for N&P and P-deficient systems. This is not the case when addressing N-deficient systems for which the use of chemicals (even for improving N removal efficiencies) is not always beneficial for the environment. A sensitivity analysis on using weighting...... of the impact categories is conducted to assess how value choices (policy decisions) may affect the management of WWTPs. For the scenarios with only N-limitation, the LCA-based ranking of the control strategies is sensitive to the choice of weighting factors, whereas this is not the case for N&P or P...

REMOVAL OF CHEMICAL AND MICROBIAL CONTAMINANTS IN DRINKING WATER - WATTS PREMIER M-2400 POINT-OF-ENTRY REVERSE OSMOSIS DRINKINGWATER TREATMENT SYSTEM

Science.gov (United States)

The Watts Premier M-2400 POE RO Drinking Water Treatment System was tested at the NSF Drinking Water Treatment Systems Laboratory for removal of the viruses fr and MS2, the bacteria Brevundimonas diminuta, and chemicals aldicarb, benzene, cadmium, carbofuran, cesium, chl...

Evaluation of a membrane bioreactor system as post-treatment waste water treatment for better removal of micropollutants

DEFF Research Database (Denmark)

Arriaga, Sonia; de Jonge, Nadieh; Lund Nielsen, Marc

2016-01-01

Organic micropollutants such as pharmaceuticals are persistent pollutants that are only partially degraded in waste water treatment plants (WWTPs). In this study, a membrane bioreactor (MBR) system was used as a polishing step on a full-scale WWTP, and its ability to remove micropollutants...

After heat removing system of a nuclear reactor

International Nuclear Information System (INIS)

Hayashi, Takao; Yamada, Masao; Ohashi, Kazutaka.

1994-01-01

In a variable conductance heat pipe of an after heat removing system, an evaporation portion and a condensator are connected by a steam diffusing path for an operation fluid and a liquid condensate recycling path. Further, incondensible gases are sealed at the inside together with the operation fluid, and a gas reservoir for the incondensible gases is disposed at the downstream of a condensation portion. If heat input is applied to the evaporation portion of the heat pipe, the incondensible gases are separated to form a boundary between both of them. When the amount of heat applied is small, the incondensible gases partially seal the condensation portion to form a local condensation insensitive portion, so that a heat conductance can be suppressed low. On the other hand, as the amount of heat inputted is increased, the incondensible gases are compressed, the heat conduction area of the condensation portion is increased and a heat conductance is increased to conduct self-control so as to increase heat transfer performance of the heat pipe. Then, the liquid condensate is recycled to the evaporation portion by spontaneous dripping of the condensate itself without wick, thereby enabling to conduct automatic switching so as to increase the heat dissipation amount to maximum. (N.H.)

A Critical Assessment of the Microorganisms Proposed to be Important to Enhanced Biological Phosphorus Removal in Full-Scale Wastewater Treatment Systems.

Science.gov (United States)

Stokholm-Bjerregaard, Mikkel; McIlroy, Simon J; Nierychlo, Marta; Karst, Søren M; Albertsen, Mads; Nielsen, Per H

2017-01-01

Understanding the microbiology of phosphorus (P) removal is considered essential to knowledge-based optimization of enhanced biological P removal (EBPR) systems. Biological P removal is achieved in these systems by promoting the growth of organisms collectively known as the polyphosphate accumulating organisms (PAOs). Also considered important to EBPR are the glycogen accumulating organisms (GAOs), which are theorized to compete with the PAOs for resources at the expense of P removal efficiency. Numerous studies have sought to identify the PAOs and their GAOs competitors, with several candidates proposed for each over the last few decades. The current study collectively assessed the abundance and diversity of all proposed PAOs and GAOs in 18 Danish full-scale wastewater treatment plants with well-working biological nutrient removal over a period of 9 years using 16S rRNA gene amplicon sequencing. The microbial community structure in all plants was relatively stable over time. Evidence for the role of the proposed PAOs and GAOs in EBPR varies and is critically assessed, in light of their calculated amplicon abundances, to indicate which of these are important in full-scale systems. Bacteria from the genus Tetrasphaera were the most abundant of the PAOs. The " Candidatus Accumulibacter" PAOs were in much lower abundance and appear to be biased by the amplicon-based method applied. The genera Dechloromonas, Microlunatus , and Tessaracoccus were identified as abundant putative PAO that require further research attention. Interestingly, the actinobacterial Micropruina and sbr-gs28 phylotypes were among the most abundant of the putative GAOs. Members of the genera Defluviicoccus, Propionivibrio , the family Competibacteraceae, and the spb280 group were also relatively abundant in some plants. Despite observed high abundances of GAOs (periodically exceeding 20% of the amplicon reads), P removal performance was maintained, indicating that these organisms were not

Full-scale radium-removal system for a small community. Research report, 1 October 1985-30 September 1987

International Nuclear Information System (INIS)

Lauch, R.P.; Mangelson, K.A.

1988-08-01

A radium-removal treatment plant was constructed for the small community of Redhill Forest in the central mountains of Colorado. The plant consists of iron removal using oxidation, filtration, and settling; radium and hardness removal using ion exchange; and radium removal from the waste brine using Dow Chemical Company's Radium Selective Complexer (RSC). The raw water comes from deep wells and has naturally occuring radium and iron concentrations of about 30-40 pC/L and 7-10 mg/L, respectively, and is aerated before entering the main treatment plant to remove radon gas and carbon dioxide. A unique feature of the plant is the process that removes radium from the waste brine. The process removes only radium from the spent ion-exchange regeneration water by permanently complexing the radium on the RSC. The RSC is replaced when exhausted and sent to a final disposal site that is acceptable to state regulatory agencies. The overall plant reduces radium from about 35 pCi/L to less than 4 pCi/L. The RSC system has consistently removed over 99% of the radium from the spent ion exchange regenerant. The average inflow radium concentration to the RSC was about 1180 pCi/L, and the average effluent was about 9 pCi/L

Containment heat removal system

International Nuclear Information System (INIS)

Wade, G.E.; Barbanti, G.; Gou, P.F.; Rao, A.S.; Hsu, L.C.

1992-01-01

This patent describes a nuclear system of a type including a containment having a nuclear reactor therein, the nuclear reactor including a pressure vessel and a core in the pressure vessel, the system. It comprises a gravity pool of coolant disposed at an elevation sufficient to permit a flow of coolant into the nuclear reactor pressure vessel against a predetermined pressure within the nuclear reactor pressure vessel; means for reducing a pressure of steam in the nuclear reactor pressure vessel to a value less than the predetermined pressure in the event of a nuclear accident, the means including a depressurization valve connected to the pressure vessel, the means further including steam heat dissipating means such dissipating means including a suppression pool; a supply of water in the suppression pool, there being a headspace in the suppression pool above the water supply; a substantial amount of air in the head space; means for feeding pressurized steam from the nuclear reactor pressure vessel to a location under a surface of the supply of water, the supply of water being effective to absorb heat sufficient to reduce steam pressure below the predetermined pressure; and a check valve for communicating the headspace with the containment, the check valve being oriented to vent air in the headspace to the containment when a pressure in the headspace exceeds a pressure in the containment by a predetermined pressure differential

Efficacy of two rotary retreatment systems in removing Gutta-percha and sealer during endodontic retreatment with or without solvent: A comparative in vitro study.

Science.gov (United States)

Bhagavaldas, Moushmi Chalakkarayil; Diwan, Abhinav; Kusumvalli, S; Pasha, Shiraz; Devale, Madhuri; Chava, Deepak Chowdary

2017-01-01

The aim of this in vitro study was to compare the efficacy of two retreatment rotary systems in the removal of Gutta-percha (GP) and sealer from the root canal walls with or without solvent. Forty-eight extracted human mandibular first premolars were prepared and obturated with GP and AH Plus sealer. Samples were then randomly divided into four groups. Group I was retreated with MtwoR rotary system without solvent, Group II was retreated with MtwoR rotary system with Endosolv R as the solvent, Group III with D-RaCe rotary system without solvent, and Group IV with D-RaCe rotary system and Endosolv R solvent. The cleanliness of canal walls was determined by stereomicroscope (×20) and AutoCAD software. Kruskal-Wallis test and Mann-Whitney U-test were used to compare the data. Results showed that none of the retreatment systems used in this study was able to completely remove the root canal filling material. D-RaCe with or without solvent showed significantly ( P > 0.05) less filling material at all levels compared to MtwoR with/without solvent. Within the limitation of the current study, D-RaCe rotary retreatment system is more effective in removing filling material from root canal walls when compared to MtwoR rotary retreatment system.

ITER cooling systems

International Nuclear Information System (INIS)

Natalizio, A.; Hollies, R.E.; Sochaski, R.O.; Stubley, P.H.

1992-06-01

The ITER reference system uses low-temperature water for heat removal and high-temperature helium for bake-out. As these systems share common equipment, bake-out cannot be performed until the cooling system is drained and dried, and the reactor cannot be started until the helium has been purged from the cooling system. This study examines the feasibility of using a single high-temperature fluid to perform both heat removal and bake-out. The high temperature required for bake-out would also be in the range for power production. The study examines cost, operational benefits, and impact on reactor safety of two options: a high-pressure water system, and a low-pressure organic system. It was concluded that the cost savings and operational benefits are significant; there are no significant adverse safety impacts from operating either the water system or the organic system; and the capital costs of both systems are comparable

PWR auxiliary systems, safety and emergency systems, accident analysis, operation

International Nuclear Information System (INIS)

Meyer, P.J.

1976-01-01

The author presents a description of PWR auxiliary systems like volume control, boric acid control, coolant purification, -degassing, -storage and -treatment system and waste processing systems. Residual heat removal systems, emergency systems and containment designs are discussed. As an accident analysis the author gives a survey over malfunctions and disturbances in the field of reactor operations. (TK) [de

Diatomite Modified Immobilized Delftia sp. for the Bio-Abiotic Removal of Antibiotics Amoxicillin in the Aqueous System

Science.gov (United States)

Gao, Lijuan; Sun, Jing; Guan, Kai; Shen, Tingting; Wang, Xikui

2017-05-01

Diatomite modified sodium alginate (Si/SA) immobilized Delftia sp. A2(2011) (STT01) was applied to degrade amoxicillin. The immobilized pellets provided a direct and visual probe for the degradation process due to their intrinsic bright colour. The results demonstrated that 100% of amoxicillin and 68.5% of CODcr removal were achieved after 72 h, comparing with the cases of sodium alginate (SA) system (81.2%, 46.9%) and the free cells system (60.5%, 35.5%). The degradation kinetics was in good agreement with Michaelis-Menten equation. The maximum rate (Vm ) and Michaelis constant (Km ) were calculated as 9.09 mg L-1 h-1 and 228 mg L-1, respectively. The results further revealed that diatomite not only acted as immobilization support to improve the mechanical strength and lifetime of the pellets but also as absorbent to promote the treatment efficiency. Therefore, both enzymatic catalysis and chemisorption were responsible for the removal of amoxicillin.

A TBB-CUDA Implementation for Background Removal in a Video-Based Fire Detection System

Directory of Open Access Journals (Sweden)

Fan Wang

2014-01-01

Full Text Available This paper presents a parallel TBB-CUDA implementation for the acceleration of single-Gaussian distribution model, which is effective for background removal in the video-based fire detection system. In this framework, TBB mainly deals with initializing work of the estimated Gaussian model running on CPU, and CUDA performs background removal and adaption of the model running on GPU. This implementation can exploit the combined computation power of TBB-CUDA, which can be applied to the real-time environment. Over 220 video sequences are utilized in the experiments. The experimental results illustrate that TBB+CUDA can achieve a higher speedup than both TBB and CUDA. The proposed framework can effectively overcome the disadvantages of limited memory bandwidth and few execution units of CPU, and it reduces data transfer latency and memory latency between CPU and GPU.

Computer based plant display and digital control system of Wolsong NPP Tritium Removal Facility

International Nuclear Information System (INIS)

Jung, C.; Smith, B.; Tosello, G.; Grosbois, J. de; Ahn, J.

2007-01-01

The Wolsong Tritium Removal Facility (WTRF) is an AECL-designed, first-of-a-kind facility that removes tritium from the heavy water that is used in systems of the CANDUM reactors in operation at the Wolsong Nuclear Power Plant in South Korea. The Plant Display and Control System (PDCS) provides digital plant monitoring and control for the WTRF and offers the advantages of state-of-the-art digital control system technologies for operations and maintenance. The overall features of the PDCS will be described and some of the specific approaches taken on the project to save construction time and costs, to reduce in-service life-cycle costs and to improve quality will be presented. The PDCS consists of two separate computer sub-systems: the Digital Control System (DCS) and the Plant Display System (PDS). The PDS provides the computer-based Human Machine Interface (HMI) for operators, and permits efficient supervisory or device level monitoring and control. A System Maintenance Console (SMC) is included in the PDS for the purpose of software and hardware configuration and on-line maintenance. A Historical Data System (HDS) is also included in the PDS as a data-server that continuously captures and logs process data and events for long-term storage and on-demand selective retrieval. The PDCS of WTRF has been designed and implemented based on an off-the-self PDS/DCS product combination, the Delta-V System from Emerson. The design includes fully redundant Ethernet network communications, controllers, power supplies and redundancy on selected I/O modules. The DCS provides field bus communications to interface with 3rd party controllers supplied on specialized skids, and supports HART communication with field transmitters. The DCS control logic was configured using a modular and graphical approach. The control strategies are primarily device control modules implemented as autonomous control loops, and implemented using IEC 61131-3 Function Block Diagram (FBD) and Structured

Development of an attached growth reactor for NH₄-N removal at a drinking water supply system in Kathmandu Valley, Nepal.

Science.gov (United States)

Khanitchaidecha, Wilawan; Shakya, Maneesha; Nakano, Yuichi; Tanaka, Yasuhiro; Kazama, Futaba

2012-01-01

Higher concentrations of ammonium (NH(4)-N) and iron (Fe) than a standard for drinking are typical characteristics of groundwater in the study area. To remove NH(4)-N and Fe, the drinking water supply system in this study consists of a series of treatment units (i.e., aeration and sedimentation, filtration, and chlorination); however, NH(4)-N in treated water is higher than a standard for drinking (i.e., removal efficiency. In accordance with raw groundwater characteristics in the area, effects of low inorganic carbon (IC) and phosphate (PO(4)-P) and high Fe on the removal efficiency were also investigated. The results showed a significant increase in NH(4)-N removal efficiency with reactor length and carrier area. A low IC and PO(4)-P had no effect on NH(4)-N removal, whereas a high Fe decreased the efficiency significantly. The first 550 days operation of a pilot-scale reactor installed in the drinking water supply system showed a gradual increase in the efficiency, reaching to 95-100%, and stability in the performance even with increased flow rate from 210 to 860 L/day. The high efficiency of the present work was indicated because only less than 1 mg of NH(4)-N/L was left over in the treated water.

Simultaneous removal of organic matter and salt ions from saline wastewater in bioelectrochemical systems

KAUST Repository

Kim, Younggy

2013-01-01

A new bioelectrochemical system is proposed for simultaneous removal of salinity and organic matter. In this process, exoelectrogenic microorganisms oxidize organic matter and transfer electrons to the anode, hydrogen is evolved at the cathode by supplying additional voltage, and salt is removed from the wastewater due to the electric potential generated and the use of two ion-exchange membranes. Salinity removal (initial conductivity ~40mS/cm) increased from 21 to 84% by increasing the substrate (sodium acetate) from 2 to 8g/L. A total of 72-94% of the chemical oxygen demand was degraded in the anode and cathode chambers, with 1-4% left in the anode chamber and the balance lost through the anion-exchange membrane into the concentrate waste chamber. The maximum hydrogen production rate was 3.6m3-H2/m3-electrolyte per day at an applied potential of 1.2V. The Coulombic efficiency was ~100%, while the cathode recovery varied from 57 to 100%, depending on the extent of methanogenesis. Exoelectrogenic microbes generated high current densities (7.8mA/cm2) at ≤36g/L of total dissolved solids, but >41g/L eliminated current. These results provide a new method for achieving simultaneous removal of salinity and organic matter from a saline wastewater with H2 production. © 2012 Elsevier B.V.

Enhanced reduction of excess sludge and nutrient removal in a pilot-scale A2O-MBR-TAD system.

Science.gov (United States)

Ventura, J S; Seo, S; Chung, I; Yeom, I; Kim, H; Oh, Y; Jahng, D

2011-01-01

In this study, a pilot scale anaerobic-anoxic-oxic (A2O) process with submerged membrane (MBR) in the oxic tank was coupled with thermophilic aerobic digestion (TAD) reactor and was operated for longer than 600 days to treat real domestic wastewater. Regardless of the varying conditions of the system, the A2O-MBR-TAD process removed MLSS, TCOD, BOD, TN, TP, and E. coli about 99%, 96%, 96%, 70%, 83%, and 99%, respectively. The additional TP removal of the system was due to the precipitating agent directly added in the oxic reactor, without which TP removal was about 56%. In the TAD reactor, receiving MLSS from the oxic tank (MBR), about 25% of TSS and VSS were solubilized during 2 days of retention. The effluent of the TAD reactor was recycled into the anoxic tank of A2O-MBR to provide organic carbon for denitrification and cryptic growth. By controlling the flowrate of wasting stream from the MBR, sludge production decreased to almost zero. From these results, it was concluded that the A2O-MBR-TAD process could be a reliable option for excellent effluent quality and near zero-sludge production.

Granulated Bog Iron Ores as Sorbents in Passive (BioRemediation Systems for Arsenic Removal

Directory of Open Access Journals (Sweden)

Klaudia Debiec

2018-03-01

Full Text Available The main element of PbRS (passive (bioremediation systems are sorbents, which act as natural filters retaining heavy metals and carriers of microorganisms involved in water treatment. Thus, the effectiveness of PbRS is determined by the quality of the (adsorbents, which should be stable under various environmental conditions, have a wide range of applications and be non-toxic to (microorganisms used in these systems. Our previous studies showed that bog iron ores (BIOs meet these requirements. However, further investigation of the physical and chemical parameters of BIOs under environmental conditions is required before their large-scale application in PbRS. The aim of this study was (i to investigate the ability of granulated BIOs (gBIOs to remove arsenic from various types of contaminated waters, and (ii to estimate the application potential of gBIOs in technologies dedicated to water treatment. These studies were conducted on synthetic solutions of arsenic and environmental samples of arsenic contaminated water using a set of adsorption columns filled with gBIOs. The experiments performed in a static system revealed that gBIOs are appropriate arsenic and zinc adsorbent. Dynamic adsorption studies confirmed these results and showed, that the actual sorption efficiency of gBIOs depends on the adsorbate concentration and is directly proportional to them. Desorption analysis showed that As-loaded gBIOs are characterized by high chemical stability and they may be reused for the (adsorption of other elements, i.e., zinc. It was also shown that gBIOs may be used for remediation of both highly oxygenated waters and groundwater or settling ponds, where the oxygen level is low, as both forms of inorganic arsenic (arsenate and arsenite were effectively removed. Arsenic concentration after treatment was <100 μg/L, which is below the limit for industrial water.

Granulated bog iron ores as sorbents in passive (bio)remediation systems for arsenic removal

Science.gov (United States)

Debiec, Klaudia; Rzepa, Grzegorz; Bajda, Tomasz; Uhrynowski, Witold; Sklodowska, Aleksandra; Krzysztoforski, Jan; Drewniak, Lukasz

2018-03-01

The main element of PbRS (passive (bio)remediation systems) are sorbents, which act as natural filters retaining heavy metals and carriers of microorganisms involved in water treatment. Thus, the effectiveness of PbRS is determined by the quality of the (ad)sorbents, which should be stable under various environmental conditions, have a wide range of applications and be non-toxic to (micro)organisms used in these systems. Our previous studies showed that bog iron ores (BIOs) meet these requirements. However, further investigation of the physical and chemical parameters of BIOs under environmental conditions is required before their large-scale application in PbRS. The aim of this study was (i) to investigate the ability of granulated BIOs (gBIOs) to remove arsenic from various types of contaminated waters, and (ii) to estimate the application potential of gBIOs in technologies dedicated to water treatment. These studies were conducted on synthetic solutions of arsenic and environmental samples of arsenic contaminated water using a set of adsorption columns filled with gBIOs. The experiments performed in a static system revealed that gBIOs are appropriate arsenic and zinc adsorbent. Dynamic adsorption studies confirmed these results and showed that the actual sorption efficiency of gBIOs depends on the adsorbate concentration and is directly proportional to them. Desorption analysis showed that As-loaded gBIOs are characterized by high chemical stability and they may be reused for the (ad)sorption of other elements, i.e. zinc. It was also shown that gBIOs may be used for remediation of both highly oxygenated waters and groundwater or settling ponds, where the oxygen level is low, as both forms of inorganic arsenic (arsenate and arsenite) were effectively removed. Arsenic concentration after treatment was <100 µg/L, which is below the limit for industrial water.

Evaluation of pain intensity measurement during the removal of wound dressing material using 'the PainVision™ system' for quantitative analysis of perception and pain sensation in healthy subjects.

Science.gov (United States)

Matsumura, Hajime; Imai, Ryutaro; Gondo, Masahide; Watanabe, Katsueki

2012-08-01

Reducing pain caused by the removal of adhesive wound dressing materials is very important in clinical practice and is also one of the factors to consider when choosing dressing materials. A visual analogue scale is the most popular method for assessing pain, but it is subjective and is difficult to evaluate quantitatively or statistically. Recently, a new method for the quantitative measurement of pain intensity using a painless electrical stimulation system, PainVision™, has been developed. In this study, we evaluated pain intensity during the removal of wound dressing materials in healthy volunteers by comparing pain during the removal of wound dressing materials, which use acrylic pressure-sensitive adhesive and pain during the removal of materials, which use soft silicone adhesive, as evaluated using the PainVision™ system. Pain intensity was significantly lower with the dressing materials, which use soft silicone adhesive when measured with the PainVision™ system. The PainVision™ system promises to be useful for the quantitative assessment of pain caused by the removal of adhesive wound dressing materials. Further studies are needed to determine whether the PainVision™ system is also effective in measuring pain caused by the removal of wound dressing materials in actual wounds. © 2012 The Authors. © 2012 Blackwell Publishing Ltd and Medicalhelplines.com Inc.

Evaluation of acrylamide-removing properties of two Lactobacillus strains under simulated gastrointestinal conditions using a dynamic system.

Science.gov (United States)

Rivas-Jimenez, L; Ramírez-Ortiz, K; González-Córdova, A F; Vallejo-Cordoba, B; Garcia, H S; Hernandez-Mendoza, A

2016-09-01

The aim of this study was to evaluate the capability of Lactobacillus reuteri NRRL 14171 and Lactobacillus casei Shirota to remove dietary acrylamide (AA) under simulated gastrointestinal conditions using a dynamic system. The effects of different AA levels or bacteria concentration on toxin removal by Lactobacillus strains were assessed. Thereafter, AA-removing capability of bacteria strains under either fasting or postprandial simulated gastrointestinal conditions was evaluated. Commercial potato chips were analyzed for their AA content, and then used as a food model. Average AA content (34,162μg/kg) in potato chips exceeded by ca. 34-fold the indicative values recommended by the EU. Toxin removal ability was dependent on AA content and bacterial cell concentration. A reduction on bacterial viability was observed in the food model and at the end of both digestive processes evaluated. However, bacteria survived in enough concentrations to remove part of the toxin (32-73%). Both bacterial strains were able to remove AA under different simulated gastrointestinal conditions, being L. casei Shirota the most effective (ca. 70% removal). These findings confirmed the risk of potato chips as dietary AA exposure for consumers, and that strains of the genus Lactobacillus could be employed to reduce the bioavailability of dietary AA. Copyright © 2016 Elsevier GmbH. All rights reserved.

In situ product removal in fermentation systems: improved process performance and rational extractant selection.

Science.gov (United States)

Dafoe, Julian T; Daugulis, Andrew J

2014-03-01

The separation of inhibitory compounds as they are produced in biotransformation and fermentation systems is termed in situ product removal (ISPR). This review examines recent ISPR strategies employing several classes of extractants including liquids, solids, gases, and combined extraction systems. Improvement through the simple application of an auxiliary phase are tabulated and summarized to indicate the breadth of recent ISPR activities. Studies within the past 5 years that have highlighted and have discussed "second phase" properties, and that have an effect on fermentation performance, are particular focus of this review. ISPR, as a demonstrably effective processing strategy, continues to be widely adopted as more applications are explored; however, focus on the properties of extractants and their rational selection based on first principle considerations will likely be key to successfully applying ISPR to more challenging target molecules.

ARSENIC REMOVAL FROM DRINKING WATER BY IRON REMOVAL PLANTS

Science.gov (United States)

This report documents a long term performance study of two iron removal water treatment plants to remove arsenic from drinking water sources. Performance information was collected from one system located in midwest for one full year and at the second system located in the farwest...

Treatment of coal gasification wastewater by a two-continuous UASB system with step-feed for COD and phenols removal

Energy Technology Data Exchange (ETDEWEB)

Wang, W.; Han, H.J.; Yuan, M.; Li, H.Q.; Fang, F.; Wang, K. [Harbin Institute of Technology, Harbin (China)

2011-05-15

A two-continuous mesophilic (37 {+-} 2{sup o}C) UASB system with step-feed was investigated as an attractive optimization strategy for enhancing COD and total phenols removal of the system and improving aerobic biodegradability of real coal gasification wastewater. Through the step-feed period, the maximum removal efficiencies of COD and total phenols reached 55-60% and 58-63% respectively in the system, at an influent flow distribution ratio of 0.2 and influent COD concentration of 2500 mg/L; the corresponding efficiencies were at low levels of 45-50% and 43-50% respectively at total HRT of 48 h during the single-feed period. The maximum specific methanogenic activity and substrate utilization rate were 592 {+-} 16 mg COD-CH{sub 4}/(gVSS d) and 89 {+-} 12 mg phenol/(gVSS d) during the step-feed operation. After the anaerobic digestion with step-feed, the aerobic effluent COD concentration decreased from 270 {+-} 9 to 215 {+-} 10 mg/L. The results suggested that step-feed enhanced the degradation of refractory organics in the second reactor.

In-pool energy removal system for emergency operation: experiment and analytical assessment

International Nuclear Information System (INIS)

Bianchi, F.; Meloni, P.; Ferri, R.; Achilli, A.

2003-01-01

In the framework of a domestic research program on innovative safety systems, ENEA has developed a device, so-called PERSEO, aimed at increasing the reliability of Residual Heat Removal Systems that implement in-pool heat exchangers. This device is suitable to transfer power from the primary side to the pool without the installation of valves on the pressurized loop, thus reducing thermal-mechanical constraints and thermal-hydraulic instabilities. The experiments have been performed at SIET Thermal-hydraulic Research Centre by modifying the existing PANTHERS IC-PCC facility and RELAP5/mod 3.2 and 3.3 beta releases have been run to perform the pre and post-test analyses respectively. The pre-test calculations provided a quantitative representation of the device behaviour and gave interesting indications on the procedures to be adopted for the experiments. The post-test calculations have been compared with the experimental data addressing particular attention to the simulation of three-dimensional effects of water circulation in both the HX and Overall Pool and have confirmed the RELAP5 code capability to fit the experimental data. The paper deals with the activity performed up to now. (author)

Assessment of alternate ion exchange resins for improved antimony removal from the primary heat transport system

Energy Technology Data Exchange (ETDEWEB)

Burany, R.; Suryanarayan, S.; Husain, A. [Kinectrics, Inc., Toronto, ON (Canada)

2015-07-01

Radiation fields around the CANDU heat transport system are a major contributor to worker dose during inspection, maintenance and refurbishment activities. While Co-60 is typically the dominant contributor to radiation fields in CANDU reactors, Sb-124, an activation product of antimony, is also a significant contributor, accounting for 5-20% of the radiation fields. The goal of this research project was to investigate resins for improved removal of antimony under both oxidizing and reducing conditions.Several candidate resins were tested and short-listed through a sequence of iterative testing. The results of the laboratory testing have identified potential candidates for improved antimony removal. Further testing is required to ensure compatibility with existing station resin specifications. (author)

Small System Use of a Solid Arsenic Oxidizing Media in Place of Chemical Oxidation to Enhance Arsenic Removals

Science.gov (United States)

As part of the USEPA Arsenic Demonstration Program, an arsenic removal adsorptive media treatment system (10 gpm) was installed at Head Start School in Buckeye Lake, Ohio on June 28, 2006. The source water (ground water) contained around 20 µg/L of arsenic, existing predominatel...

HYLIFE-II tritium management system

International Nuclear Information System (INIS)

Longhurst, G.R.; Dolan, T.J.

1993-06-01

The tritium management system performs seven functions: (1) tritium gas removal from the blast chamber, (2) tritium removal from the Flibe, (3) tritium removal from helium sweep gas, (4) tritium removal from room air, (5) hydrogen isotope separation, (6) release of non-hazardous gases through the stack, (7) fixation and disposal of hazardous effluents. About 2 TBq/s (5 MCi/day) of tritium is bred in the Flibe (Li 2 BeF 4 ) molten salt coolant by neutron absorption. Tritium removal is accomplished by a two-stage vacuum disengager in each of three steam generator loops. Each stage consists of a spray of 0.4 mm diameter, hot Flibe droplets into a vacuum chamber 4 m in diameter and 7 m tall. As droplets fall downward into the vacuum, most of the tritium diffuses out and is pumped away. A fraction Φ∼10 -5 of the tritium remains in the Flibe as it leaves the second stage of the vacuum disengager, and about 24% of the remaining tritium penetrates through the steam generator tubes, per pass, so the net leakage into the steam system is about 4.7 MBq/s (11 Ci/day). The required Flibe pumping power for the vacuum disengager system is 6.6 MW. With Flibe primary coolant and a vacuum disengager, an intermediate coolant loop is not needed to prevent tritium from leaking into the steam system. An experiment is needed to demonstrate vacuum disengager operation with Flibe. A secondary containment shell with helium sweep gas captures the tritium permeating out of the Flibe ducts, limiting leaks there to about 1 Ci/day. The tritium inventory in the reactor is about 190 g, residing mostly in the large Flibe recirculation duct walls. The total cost of the tritium management system is 92 M$, of which the vacuum disengagers cost = 56%, the blast chamber vacuum system = 15%, the cryogenic plant = 9%, the emergency air cleanup and waste treatment systems each = 6%, the protium removal system = 3%, and the fuel storage system and inert gas system each = 2%

A Critical Assessment of the Microorganisms Proposed to be Important to Enhanced Biological Phosphorus Removal in Full-Scale Wastewater Treatment Systems

Directory of Open Access Journals (Sweden)

Per H. Nielsen

2017-04-01

Full Text Available Understanding the microbiology of phosphorus (P removal is considered essential to knowledge-based optimization of enhanced biological P removal (EBPR systems. Biological P removal is achieved in these systems by promoting the growth of organisms collectively known as the polyphosphate accumulating organisms (PAOs. Also considered important to EBPR are the glycogen accumulating organisms (GAOs, which are theorized to compete with the PAOs for resources at the expense of P removal efficiency. Numerous studies have sought to identify the PAOs and their GAOs competitors, with several candidates proposed for each over the last few decades. The current study collectively assessed the abundance and diversity of all proposed PAOs and GAOs in 18 Danish full-scale wastewater treatment plants with well-working biological nutrient removal over a period of 9 years using 16S rRNA gene amplicon sequencing. The microbial community structure in all plants was relatively stable over time. Evidence for the role of the proposed PAOs and GAOs in EBPR varies and is critically assessed, in light of their calculated amplicon abundances, to indicate which of these are important in full-scale systems. Bacteria from the genus Tetrasphaera were the most abundant of the PAOs. The “Candidatus Accumulibacter” PAOs were in much lower abundance and appear to be biased by the amplicon-based method applied. The genera Dechloromonas, Microlunatus, and Tessaracoccus were identified as abundant putative PAO that require further research attention. Interestingly, the actinobacterial Micropruina and sbr-gs28 phylotypes were among the most abundant of the putative GAOs. Members of the genera Defluviicoccus, Propionivibrio, the family Competibacteraceae, and the spb280 group were also relatively abundant in some plants. Despite observed high abundances of GAOs (periodically exceeding 20% of the amplicon reads, P removal performance was maintained, indicating that these organisms

In vitro evaluation of the effectiveness of ProTaper universal rotary retreatment system for gutta-percha removal with or without a solvent.

Science.gov (United States)

Takahashi, Cristiane Midori; Cunha, Rodrigo Sanches; de Martin, Alexandre Sigrist; Fontana, Carlos Eduardo; Silveira, Cláudia Fernandes M; da Silveira Bueno, Carlos Eduardo

2009-11-01

Effective removal of gutta-percha in endodontic retreatment is a significant factor to ensure a favorable outcome from failed procedures. The purpose of this study was to evaluate the efficacy of a nickel-titanium rotary instrument system with or without a solvent versus stainless steel hand files for gutta-percha removal. Forty extracted human maxillary anterior teeth were prepared and filled. They were divided into 4 groups: Gates-Glidden and K-files, Gates-Glidden and K-files with chloroform, ProTaper Universal rotary retreatment system, and ProTaper Universal rotary retreatment system with chloroform. The operating time was recorded. The teeth were longitudinally sectioned and photographed. The images were analyzed and the filling remnants were quantified by using the IMAGE TOOL software. With Kruskall-Wallis test, statistical analysis showed that there was no significant difference between the techniques in regard to the amount of the endodontic filling remnants (P ProTaper Universal rotary retreatment system was faster than the hand files (P ProTaper Universal rotary retreatment system without chloroform was faster.

Continuous energy recovery and nutrients removal from molasses wastewater by synergistic system of dark fermentation and algal culture under various fermentation types.

Science.gov (United States)

Ren, Hong-Yu; Kong, Fanying; Ma, Jun; Zhao, Lei; Xie, Guo-Jun; Xing, Defeng; Guo, Wan-Qian; Liu, Bing-Feng; Ren, Nan-Qi

2018-03-01

Synergistic system of dark fermentation and algal culture was initially operated at batch mode to investigate the energy production and nutrients removal from molasses wastewater in butyrate-type, ethanol-type and propionate-type fermentations. Butyrate-type fermentation was the most appropriate fermentation type for the synergistic system and exhibited the accumulative hydrogen volume of 658.3 mL L -1 and hydrogen yield of 131.7 mL g -1 COD. By-products from dark fermentation (mainly acetate and butyrate) were further used to cultivate oleaginous microalgae. The maximum algal biomass and lipid content reached 1.01 g L -1 and 38.5%, respectively. In continuous operation, the synergistic system was stable and efficient, and energy production increased from 8.77 kJ L -1  d -1 (dark fermentation) to 17.3 kJ L -1  d -1 (synergistic system). Total COD, TN and TP removal efficiencies in the synergistic system reached 91.1%, 89.1% and 85.7%, respectively. This study shows the potential of the synergistic system in energy recovery and wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

324 Building liquid waste handling and removal system project plan

Energy Technology Data Exchange (ETDEWEB)

Ham, J.E.

1998-07-29

This report evaluates the modification options for handling radiological liquid waste generated during decontamination and cleanout of the 324 Building. Recent discussions indicate that the Hanford site railroad system will be closed by the end of FY 1998 necessitating the need for an alternate transfer method. The issue of handling of Radioactive Liquid Waste (RLW) from the 324 Building (assuming the 340 Facility is not available to accept the RLW) has been examined in at least two earlier engineering studies (Parsons 1997a and Hobart 1997). Each study identified a similar preferred alternative that included modifying the 324 Building RLWS to allow load-out of wastewater to a truck tanker, while making maximum use of existing piping, tanks, instrumentation, controls and other features to minimize costs and physical changes to the building. This alternative is accepted as the basis for further discussion presented in this study. The goal of this engineering study is to verify the path forward presented in the previous studies and assure that the selected alternative satisfies the 324 Building deactivation goals and objectives as currently described in the project management plan. This study will also evaluate options available to implement the preferred alternative and select the preferred option for implementation of the entire system. Items requiring further examination will also be identified. Finally, the study will provide a conceptual design, schedule and cost estimate for the required modifications to the 324 Building to allow removal of RLW. Attachment 5 is an excerpt from the project baseline schedule found in the Project Management Plan.

AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT XVII, I--MAINTAINING THE LUBRICATION SYSTEM--CUMMINS DIESEL ENGINE, II--UNIT INSTALLATION AND REMOVAL--DRIVE LINES.

Science.gov (United States)

Minnesota State Dept. of Education, St. Paul. Div. of Vocational and Technical Education.

THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE DIESEL ENGINE LUBRICATION SYSTEM AND THE PROCEDURES FOR REMOVAL AND INSTALLATION OF THE DRIVE LINE USED IN DIESEL ENGINE POWER DISTRIBUTION. TOPICS ARE (1) PROLONGING ENGINE LIFE, (2) FUNCTIONS OF THE LUBRICATING SYSTEM, (3) TRACING THE LUBRICANT FLOW, (4) DETERMINING…

Effectiveness of seawater reverse osmosis (SWRO) pretreatment systems in removing transparent exopolymer particles (TEP) substances

KAUST Repository

Lee, Shang-Tse

2015-05-01

Transparent exopolymer particles (TEP) have been reported as one of the main factors of membrane fouling in seawater reverse osmosis (SWRO) process. Research has been focused on algal TEP so far, overlooking bacterial TEP. This thesis investigated the effects of coagulation on removal of bacterial TEP/TEP precursors in seawater and subsequent reduction on TEP fouling in ultrafiltration (UF), as a pretreatment of SWRO. Furthermore, the performance of pretreatment (coagulation + UF) has been investigated on a bench-scale SWRO system. TEP/TEP precursors were harvested from a strain of marine bacteria, Pseudoalteromonas atlantica, isolated from the Red Sea. Isolated bacterial organic matter (BOM), containing 1.5 mg xanthan gum eq./L TEP/TEP precursors, were dosed in Red Sea water to mimic a high TEP concentration event. Bacterial TEP/TEP precursors added to seawater were coagulated with ferric chloride and aluminum sulfate at different dosages and pH. Results showed that ferric chloride had a better removal efficiency on TEP/TEP precursors. Afterwards, the non-coagulated/coagulated seawater were tested on a UF system at a constant flux of 130 L/m2h, using two types of commercially available membranes, with pore sizes of 50 kDa and 100 kDa, respectively. The fouling potential of coagulated water was determined by the Modified Fouling Index (MFI-UF). Transmembrane pressure (TMP) was also continuously monitored to investigate the fouling development on UF membranes. TEP concentrations in samples were determined by the alcian blue staining assay. Liquid chromatography-organic carbon detection (LC-OCD) was used to determine the removal of TEP precursors with particular emphasis on biopolymers. Finally, SWRO tests showed that TEP/TEP precursors had a high fouling potential as indicated by MFI-UF, corresponding to the TMP measurements. Coagulation could substantially reduce TEP/TEP precursors fouling in UF when its dosage was equal or higher than 0.2 mg Fe/L. The flux decline

Characterization of algae removal in a fluidized bed biofilm reactor system for lake water treatment; Kokisei ryudosho seibutsu rokaho ni yoru kosuichu no sorui jokyo tokusei

Energy Technology Data Exchange (ETDEWEB)

Tanaka, T.; Tsuzuki, K.; Nishijima, N.; Takagi, T. [Hitachi, Ltd., Tokyo (Japan); Terazono, K. [Water Resources Environment Technology Center, Tokyo (Japan)

1998-04-10

This paper describes a pilot plant study on algae removal of a fluidized bed biofilm reactor system for lake water treatment. The system does not need backwashing because the fluidized bed suffers no clogging. Moreover, the system uses dissolved oxygen in influent water for aerobic biological treatment without aeration equipment. Thus, this system is a low energy and easy maintenance way to purify eutrophic lake water. The system was operated continuously at a flow rate of 1500 m{sup 3}/d{sup 1} for 9 months at Tsuchiura Port in Lake Kasumigaura. In this study, chlorophyll-a and dissolved oxygen in both influent and effluent water were monitored continuously. In summer (August to September) when water bloom occurred, the average removal efficiency of chlorophyll-a was 64% at the average influent chlorophyll-a concentration of 137.8 {mu}g/l{sup 1}. During the total experimental period (9 months), the average daily amount of removed chlorophyll-a was 40.3 g/d{sup 1} at the average influent chlorophyll-a concentration of 89.5 {mu}g/l{sup 1}. By analyzing the relationship between the removed chlorophyll-a and the consumption of dissolved oxygen, it was estimated that almost all of algae trapped in the reactor was degraded biologically. 20 refs., 12 figs., 2 tabs.

Core cooling system for reactor

International Nuclear Information System (INIS)

Kondo, Ryoichi; Amada, Tatsuo.

1976-01-01

Purpose: To improve the function of residual heat dissipation from the reactor core in case of emergency by providing a secondary cooling system flow channel, through which fluid having been subjected to heat exchange with the fluid flowing in a primary cooling system flow channel flows, with a core residual heat removal system in parallel with a main cooling system provided with a steam generator. Constitution: Heat generated in the core during normal reactor operation is transferred from a primary cooling system flow channel to a secondary cooling system flow channel through a main heat exchanger and then transferred through a steam generator to a water-steam system flow channel. In the event if removal of heat from the core by the main cooling system becomes impossible due to such cause as breakage of the duct line of the primary cooling system flow channel or a trouble in a primary cooling system pump, a flow control valve is opened, and steam generator inlet and outlet valves are closed, thus increasing the flow rate in the core residual heat removal system. Thereafter, a blower is started to cause dissipation of the core residual heat from the flow channel of a system for heat dissipation to atmosphere. (Seki, T.)

Sparing analysis for FGD systems

International Nuclear Information System (INIS)

Dene, C.E.; Weiss, J.; Twombly, M.A.; Witt, J.

1992-01-01

With the passage of federal clean air legislation, utilities will be evaluating the capability of various flue gas desulfurization (FGD) system design configurations and operating scenarios to meet sulfur dioxide (SO 2 ) removal goals. The primary goal in reviewing these alternatives will be to optimize SO 2 removal capability in relation to power production costs. The Electric Power Research institute (EPRI) and its contractor, ARINC Research Corporation, have developed an automated FGD Analysis System that can evaluate competing FGD design alternatives in terms of their SO 2 removal capability and operating costs. The FGD Analysis System can be used to evaluate different design configurations for new systems or to calculate the effect of changes in component reliability for existing FGD systems. The system is based on the EPRI UNIRAM methodology and evaluates the impact of alternative FGD component configurations on the expected unit emission rates. The user interactively enters FGD design data, unit SO 2 generation-level data, and FGD chemical additive-level data for the design configuration to be evaluated. The system then calculates expected SO 2 removal capability and operating cost data for operation of the design configuration over a user specified time period. This paper provides a brief description of the FGD Analysis System and presents sample results for three typical design configurations with different redundancy levels

Preliminary analysis of West Valley Waste Removal System equipment development and mock demonstration facilities

International Nuclear Information System (INIS)

Janicek, G.P.

1981-06-01

This report defines seven areas requiring further investigation to develop and demonstrate a safe and viable West Valley Waste Removal System. These areas of endeavor are discussed in terms of their minimum facility requirements. It is concluded that utilizing separated specific facilities at different points in time is of a greater advantage than an exact duplication of the West Valley tanks. Savannah River Plant's full-scale, full-circle and half-circle tanks, and their twelfth scale model tank would all be useful to varying degrees but would require modifications. Hanford's proposed full-size mock tank would be useful, but is not seriously considered because its construction may not coincide with West Valley needs. Costs of modifying existing facilities and/or constructing new facilities are assessed in terms of their benefit to the equipment development and mock demonstration. Six facilities were identified for further analysis which would benefit development of waste removal equipment

Enhancing organic matter removal in desalination pretreatment systems by application of dissolved air flotation

DEFF Research Database (Denmark)

Shutova, Yulia; Karna, Barun Lal; Hambly, Adam C.

2016-01-01

on the sample, respectively. The optimal normalised coagulant dose (Fe3+ to DOC ratio) was observed to be 0.5-4 at pH5.5 increasing to 4-12 at pH7.5. At pH5.5, the optimum coagulant dose increased with increasing humic character of the feed water. Overall, the OM removal efficiency by DAF observed in this study......Membrane fouling in reverse osmosis (RO) systems caused by organic matter (OM) remains a significant operational issue during desalination. Dissolved air flotation (DAF) has recently received attention as a pre-treatment option for seawater OM removal; however, only a limited number of studies have...... been undertaken. This may be because it is difficult to characterise OM in seawater due to the high salt content and low carbon concentration. In this study, DAF pre-treatment experiments were conducted using a model seawater solution, and real seawater and brackish water samples. DAF performance...

Characterization of a collection of plasmid-containing bacteria isolated from an on-farm biopurification system used for pesticide removal

NARCIS (Netherlands)

Carla Martini, Maria; Javier Albicoro, Francisco; Nour, Eman; Schlueter, Andreas; van Elsas, Jan Dirk; Springael, Dirk; Smalla, Kornelia; Pistorio, Mariano; Lagares, Antonio; Florencia Del Papa, Maria

Biopurification systems (BPS) are complex soil-related and artificially-generated environments usually designed for the removal of toxic compounds from contaminated wastewaters. The present study has been conducted to isolate and characterize a collection of cultivable plasmid-carrying bacterial

Development of a system for rapid discharge of spherical fuel elements as a diversitary afterheat removal system for pebble-bed HTR-type reactors

International Nuclear Information System (INIS)

Phlippen, P.W.

1982-07-01

Owing to its spherical fuel elements the pebble bed high temperature reactor provides the possibility to remove these fuel elements rapidly from the reactor for the purpose of after-heat removal and cooling in situations of danger and to collect them in easily cooled tanks. The paper investigates and represents fields of problems such as critically behaviour of core and fuel element collecting tanks, emission time of the core, thermodynamics in the vessel etc. by example of the PNP-500 reactor concept. A selection for the construction proposal was made from the performance possibilities of the three necessary main components prestressed-concrete vessel closure, fuel element guide and fuel element storage with cooling system. The proposal includes a prestressed concrete vessel closure opening by hydraulics as well as three annular fuel element storage modules cooled with the containment air by natural convection. (orig.) [de