scholarly journals ENHANCED FILTER MATERIAL FOR PATHOGEN REMOVAL

2021 ◽  
Author(s):  
WENDY KUHNE
Keyword(s):  
Filter Material ◽  
Pathogen Removal

scholarly journals Unravelling the process of petroleum hydrocarbon biodegradation in different filter materials of constructed wetlands by stable isotope fractionation and labelling studies

2021 ◽  
Author(s):  
Andrea Watzinger ◽  
Melanie Hager ◽  
Thomas Reichenauer ◽  
Gerhard Soja ◽  
Paul Kinner
Keyword(s):  
Stable Isotope ◽  
Constructed Wetlands ◽  
Hydrogen Isotope ◽  
Petroleum Hydrocarbon ◽  
Isotope Fractionation ◽  
Isotope Effects ◽  
Filter Material ◽  
Hydrocarbon Biodegradation ◽  
Stable Isotope Fractionation ◽  
Filter Materials

AbstractMaintaining and supporting complete biodegradation during remediation of petroleum hydrocarbon contaminated groundwater in constructed wetlands is vital for the final destruction and removal of contaminants. We aimed to compare and gain insight into biodegradation and explore possible limitations in different filter materials (sand, sand amended with biochar, expanded clay). These filters were collected from constructed wetlands after two years of operation and batch experiments were conducted using two stable isotope techniques; (i) carbon isotope labelling of hexadecane and (ii) hydrogen isotope fractionation of decane. Both hydrocarbon compounds hexadecane and decane were biodegraded. The mineralization rate of hexadecane was higher in the sandy filter material (3.6 µg CO2 g−1 day−1) than in the expanded clay (1.0 µg CO2 g−1 day−1). The microbial community of the constructed wetland microcosms was dominated by Gram negative bacteria and fungi and was specific for the different filter materials while hexadecane was primarily anabolized by bacteria. Adsorption / desorption of petroleum hydrocarbons in expanded clay was observed, which might not hinder but delay biodegradation. Very few cases of hydrogen isotope fractionation were recorded in expanded clay and sand & biochar filters during decane biodegradation. In sand filters, decane was biodegraded more slowly and hydrogen isotope fractionation was visible. Still, the range of observed apparent kinetic hydrogen isotope effects (AKIEH = 1.072–1.500) and apparent decane biodegradation rates (k = − 0.017 to − 0.067 day−1) of the sand filter were low. To conclude, low biodegradation rates, small hydrogen isotope fractionation, zero order mineralization kinetics and lack of microbial biomass growth indicated that mass transfer controlled biodegradation.

Determination of Free Solanesol Levels in Cigarette Filters by Liquid Chromatography–Mass Spectrometry

2021 ◽  
Author(s):  
Roberto Bravo Cardenas ◽  
Phuong Ngac ◽  
Clifford Watson ◽  
Liza Valentin-Blasini
Keyword(s):  
Liquid Chromatography ◽  
Sample Preparation ◽  
Tobacco Smoke ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Filter Material ◽  
Previous Method ◽  
Tobacco Smoke Exposure ◽  
Triple Quadrupole Mass Spectrometer ◽  
Cigarette Butts

Abstract Solanesol, a naturally occurring constituent of tobacco, has been utilized as a good marker for environmental tobacco smoke particulate and as a noninvasive predictor of mainstream cigarette smoke tar and nicotine intake under naturalistic smoking conditions. A fast and accurate method for measuring free solanesol to assess tobacco smoke exposure is highly desirable. We have developed and validated a new environmentally friendly, high-throughput method for measuring solanesol content in discarded cigarette filter butts. The solanesol deposited in the used filters can be correlated with mainstream smoke deliveries of nicotine and total particle matter to estimate constituent delivery to smokers. A portion of filter material is removed from cigarette butts after machine smoking, spiked with internal standard solution, extracted and quantitatively analyzed using reverse-phase liquid chromatography coupled to a triple-quadrupole mass spectrometer. The new method incorporates a 48-well plate format for automated sample preparation that reduces sample preparation time and solvent use and increases sample throughput 10-fold compared to our previous method. Accuracy and precision were evaluated by spiking known amounts of solanesol on both clean and smoked cigarette butts. Recoveries exceeded 93% at both low and high spiking levels. Linear solanesol calibration curves ranged from 1.9 to 367 µg/butt with a 0.05 µg/butt limit of detection.

scholarly journals A Preliminary Study on the Use of Xylit as Filter Material for Domestic Wastewater Treatment

2021 ◽  
Vol 11 (11) ◽  
pp. 5281
Author(s):  
Marcin Spychała ◽  
Tadeusz Nawrot ◽  
Radosław Matz
Keyword(s):  
Quality Indicators ◽  
Initial Period ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Filter Material ◽  
Stage I ◽  
Stage Ii ◽  
Septic Tank ◽  
Preliminary Stage ◽  
Wastewater Quality

The aim of the study was to verify two morphological forms (“angel hair” and “scraps”) of xylit as a trickling filter material. The study was carried out on two types of polluted media: septic tank effluent (STE) and seminatural greywater (GW). The basic wastewater quality indicators, namely, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total suspended solids (TSS), ammonium nitrogen (NNH4), and total phosphorus (Ptot) were used as the indicators of treatment efficiency. Filtering columns filled with the investigated material acted as conventional trickling filters at a hydraulic load of 376–472 cm3/d during the preliminary stage, 198–245 cm3/d during stage I, and 184–223 cm3/d during stage II. The removal efficiency of the two morphological forms of xylit did not differ significantly. The average efficiencies of treatment were as follows: for COD, over 70, 80, and 85% for preliminary stage, stage I and stage II, respectively; for BOD5, 77–79% (preliminary stage); for TSS, 42% and 70% during the preliminary stage, and 88, 91, and 65% during stage I; for NNH4, 97–99% for stage I and 36–49% for stage II; for Ptot, 51–54% for stage I and 52–56% for stage II. The study demonstrated that xylit was a material highly effective in wastewater quality indicators removal, even during the initial period of its use.

Survival of Mycobacteria on Hepa Filter Material

1998 ◽  
Vol 3 (2) ◽  
pp. 65-78 ◽  
Author(s):  
Gwangpyo Ko ◽  
Harriet A. Burge ◽  
Michael Muilenberg ◽  
Stephen Rudnick ◽  
Melvin First
Keyword(s):  
High Efficiency ◽  
Ventilation System ◽  
Filter Material ◽  
Survival Curves ◽  
Mycobacterium Chelonae ◽  
Air Filters ◽  
Liquid Suspension ◽  
Static Conditions ◽  
Strain H37rv ◽  
Over Time

Mycobacterium tuberculosis (MTB) is transmitted through the air, and can be captured on ventilation air filters. People handling these filters may be exposed to infectious material. We studied the survival of strains of Mycobacterium on high efficiency particulate air (HEPA) filter material. We used a model ventilation system to evaluate survival over time of Mycobacterium chelonae and H37Ra (an avirulent stain of MTB) aerosolized and then captured on HEPA filter material. Survival curves for M. chelonae incubated at 55% and 75% RH under static conditions were not different with less than 4% survival at 24 hours. H37Ra was subjected to continuous airflow at the design airflow for the filter material following deposition on the HEPA filter material, and less than 0.1% of cells survived to 48 hours (RH not controlled). H37Ra was resistant to immobilized biocide (trimethoxysilylpropyl dimethyloctadecyl ammonium chloride) on HEPA filter material as well as the same biocide in solution. Finally, survival of H37Ra and virulent MTB strain (H37Rv) were not different following deposition onto HEPA filter material from liquid suspension and incubation under static conditions.

The effect of filter material on bioaerosol collection of Bacillus subtilis spores used as a Bacillus anthracis simulant

2005 ◽  
Vol 7 (5) ◽  
pp. 475 ◽  
Author(s):  
Nancy Clark Burton ◽  
Atin Adhikari ◽  
Sergey A. Grinshpun ◽  
Richard Hornung ◽  
Tiina Reponen
Keyword(s):  
Bacillus Subtilis ◽  
Bacillus Anthracis ◽  
Filter Material

Evaluating the Efficiency of Crushed Gravel Filters around Field Drains

2021 ◽  
Author(s):  
Amer Al-Haddad ◽  
◽  
Dhuha Mahdi ◽  
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Surface ◽  
Filter Material ◽  
Head Loss ◽  
Surface Flow ◽  
Laboratory Work ◽  
Drain Pipe ◽  
Drainage Systems ◽  
Total Head ◽  
Irrigation Condition

Engineers have employed various ways to protect drain openings from the entry of sediment with varying degrees of success. This study aims to compare and evaluate the hydraulic performance and efficiency of using natural graded gravel filter and crushed gravel filter in drainage systems. An aquifer tank (sand tank) 70 cm long, 50 cm wide and 80 cm high, a perforated drain pipe of 50 mm diameter was used in the laboratory work. The laboratory study was performed with two types of soil: loam and loamy sand. These two soils were used with the two types of gravel filters after taking the particle size distribution test for the two soils. For each case, the inflow was applied to the model from the soil surface (to represent irrigation condition) and from the sides of the tank (to represent sub –surface flow condition and effluence of the groundwater). Each case involved ten runs; for each run, discharge, total head loss, and amount of sediment were recorded. It was found that crushed gravel filter would work similarly to natural graded gravel filter after a certain time from the beginning of runs. It was also found that the discharge and sediment when using crushed gravel filter were close to or equal to that with natural graded gravel filter. The hydraulic conductivity and the exit gradient values were calculated in this research. It was found that their values were so different between the two types of filters, but at the end of the laboratory work, the hydraulic conductivity would be approximately the same. The exit gradient of crushed gravel filter was lower than that of natural graded gravel filter due to the large pores between the filter particles. Finally, the results showed that, it is possible to use crushed gravel filter material in drainage systems, which is less costly and easier to place than natural graded gravel filter.

Synthesis of Macro-Porous De-NOx Catalysts for Poly-Tetra-Fluoro-Ethylene Membrane Bag Filter

2021 ◽  
Vol 21 (8) ◽  
pp. 4537-4543
Author(s):  
Byung Chan Kwon ◽  
Dohyung Kang ◽  
Seung Woo Lee ◽  
No-Kuk Park ◽  
Jang Hun Lee ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Nitrogen Oxides ◽  
Porous Alumina ◽  
Combustion Process ◽  
Textural Properties ◽  
Filter Material ◽  
Facilitated Diffusion ◽  
Exhaust Gas ◽  
Bag Filter ◽  
Combustion Exhaust

This study examined the effects of the porosity of catalytic bag-filter materials for applications to the SNCR (selective noncatalytic reduction)-SCR (selective catalytic reduction) hybrid process for highly treating nitrogen Oxides (NOx) in the exhaust gas of a combustion process. A V2O5/TiO2 catalyst was dispersed in a PTFE (poly-tetra-fluoro-ethylene) used as the catalytic bag-filter material to remove particulate matter and nitrogen oxides contained in the combustion exhaust gas. Macroporous alumina was added into a V2O5/TiO2-dispersed PTFE to improve the catalytic activity of V2O5/TiO2 dispersed in the PTFE material. In this study, the textural properties and denitrification performances of the V2O5/TiO2-dispersed PTFE materials were examined according to the addition of macro-porous alumina. When the denitrification catalyst was solely dispersed in the PTFE material, the catalyst inside the PTFE backbone had low gas-solid contact efficiency owing to the low porosity of the PTFE materials, resulting in low denitrification efficiency. On the other hand, the catalytic activity of V2O5/TiO2 dispersed inside the macro-porous PTFE material was significantly enhanced by adding macro-porous alumina into the PTFE matrix. The enhanced textural properties of the macro-porous PTFE material where V2O5/TiO2 was uniformly dispersed proved the facilitated diffusion of combustion exhaust gas into the PTFE material.

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