A unique accelerated aging chamber for experimentally determining the life of nuclear grade high efficiency particulate air (HEPA) filters was designed, implemented, and characterized. A design document was developed under the Nuclear Quality Assurance program (NQA-1). The aging process is achieved by sustaining an elevated humidity condition inside the chamber for an extended period of time. Elevated humidity conditions expose the media to commonly occurring stressors that mimic the degradation a typical filter in practical applications would experience. The aged media may then be analyzed using autopsy methodology resulting in data that can be used to better understand the useful life of HEPA filters. The chamber allows age studies to be conducted in a fraction of the time. The industry requires a more complete understanding of the useful life of HEPA filters as opposed to the rule of thumb which states to dispose filters 10 years after the manufacture date.

In the recent century, a process of urbanization has increased globally. Previously rural or natural land have been converted into impervious surfaces to make way for housing, industries, and roads. This anthropogenic process has resulted in an increased amount of surface runoff from precipitation, so-called stormwater. Stormwater can accumulate a range of pollutants when it flows over the impervious surfaces of our cities. These pollutants can have a negative impact on the lakes and streams that receive the stormwater from the urban environments. To reduce the environmental problems associated with the content of stormwater, various techniques have been developed for stormwater treatment, with the aim of reducing the pollutant load in the runoff before it enters the receiving waterbody. One such technology is stormwater biofiltration, also known as bioretention. Stormwater biofilters were developed in the USA in the early 90's and they utilize the natural water remediation properties of plant-soil systems. They are generally characterized by a vegetated submerged filter bed with an underlying drainage layer. They have shown to be an effective method for stormwater pollutant removal. The treatment processes take place both in the vegetation and in filter material. As th ematerial choices and design of the biofilters can vary, so can its treatment performance. Stormwater biofilters have grown in popularity in the last decades since their development and numerous studies have been conducted to evaluate the systems’ treatment efficiency. However, knowledge gaps still exist regarding their implementation in colder climates and the suitability of different configurations and materials. This study examines the removal performance of total and dissolved heavy metals (Cd (cadmium),Cu (copper), Pb (lead) and Zn (zinc)), phosphorus, nitrogen and total suspended solids (TSS) in three stormwater biofilters in a Swedish climate, located in central Malmö. The current biofilters are designed with different configurations of their filter media and are built with 1) sand-basedfilter material 2) sand-based filter material with a submerged zone and 3) filter media consisting of 50% sand-based material in combination with 50% pumice. The results showed that the treatment capacity of the biofilters with a filter media of only sand (biofilter S) and with sand as well as a submerged zone (biofilter S_SZ) was similar for all pollutants. The reduction of total levels of metals (> 85 %) and TSS (>90 %) was consistently high and similar to levels achieved in previous studies for both temperate and colder climates. The removal of dissolved metals was lower in comparison to the removal of the total metal fractions, but the dissolved fractions were still generally reduced in the effluent. A positive removal of total phosphorus and total nitrogen was overall displayed in the effluent from the two biofilters; however,leaching was shown for the dissolved fractions. For nitrogen (N) species, the concentrations in the runoff were generally below the detection limit for the analysis making it difficult to establish probable removal percentages. For the biofilter S_P, which contained a mix of sand and pumice, the removal capacity was lowerfor all parameters compared to the other designs. Overall, the pollutant removal performances are regarded to be satisfactory for biofilters S andS_SZ and their implementation suitable for the given site. However, further investigations should be performed during warmer seasons, especially regarding the removal of nutrients.

No description available.

No description available.

Roads, buildings, vehicles, and human activities cause spreading of pollutants, which partly end up in stormwater. The pollutant load contains solid particles of various size, hydrocarbons, organics, metals, nutrients, and microorganisms, which can have negative effects on water quality of surface-, coastal- and ground waters. Furthermore, urban development causes hardening of ground and reduced soil permeability that promotes rapid runoff during precipitation. The conversion from permeable to impermeable surfaces therefore lead to increased volumes stormwater but also decrease in stormwater water quality.  Stormwater runoff metals are bound to various particles or occur in the dissolved fraction which is more toxic to aquatic life. Infiltration to soil, sand or other media is common practice to reduce runoff and filtrate metals and many treatment facilities and filter media have therefore been assessed for their metal removal efficiencies. High metal removal is often achieved for total metals, but removal of dissolved fraction remains elusive in many studies. Hence the importance of evaluate removal of dissolved metals before application to stormwater treatment facilities.  The experimental column study of metal removal using commercially available reactive filter media showed that all filter media removal efficiencies in the order of zinc > copper > nickel. Removal efficiencies of chromium and lead were not considerably higher in tested filter media compared to the reference filter sand. Two filter media also leached chromium during the initial part of the experiment. / Vägar, byggnader, fordon och mänskliga aktiviteter orsakar spridning av föroreningar av vilka en del förekommer i dagvatten. Urban bebyggelse orsakar också hårdgörande av ytor och reducerar jordens permeabilitet vilket skapar snabb avrinning vid nederbörd. Avrinningen innehåller bland annat partiklar, kolväten och andra organiska ämnen, metaller, näringsämnen och mikroorganismer vilka kan ha negativa effekter på yt-, kust- och grundvatten. Omvandlingen till hårdgjorda ytor orsakar därför både ökade volymer avrinning och sämre vattenkvalité.  Metaller i dagvatten är ofta bundna till olika partiklar eller förekommer i löst form där den lösta formen anses vara mest miljöfarlig. Infiltration i jord, sand eller annan media är vanliga sätt att reducera avrinning och filtrera metaller. Hög förmåga att avskilja metaller kan ofta hittas för totala koncentrationen av metall men avskiljning av den lösta formen är ofta oklar. Utvärdering av olika filtermaterials förmåga att reducera lösta metaller är därför av särskilt intresse.  Kolonnförsöken gjorda för att utvärdera metallavskiljningskapacitet med kommersiellt tillgängliga reaktiva filtermaterial har i denna uppsats visat att filtermaterialen har högst procentuell avskiljning för zink följt av koppar och därefter nickel. Krom och bly avskiljs inte mer i dessa filtermaterial än vad de gör i sandfilter. Två av filtermaterial läckte dessutom initialt höga koncentrationer krom.

No description available.

Concerns about potential risks posed by discharge from small-scale wastewater treatment (SWT) systems to receiving water bodies have prompted robust enforcement of national discharge quality standards in rural areas of most developed countries. Consequently, communities in such places are in need of effective technologies with which to achieve compliance. Currently, reactive filter (RF) media are increasingly preferred over advanced alternatives, due mainly to their simplicity, affordability and proven potential. However, many of the field-tested filters are commercial products which are costly and scarce but also only capable of removing few contaminants they are engineered to target hence often requiring to be coupled with other treatment units to achieve full treatment. In the preliminary findings of this study, biochar (BC) was identified and thus suggested basing on existing literature, as a versatile ubiquitous low-cost material for treating wastewater. Its effectiveness in fortifying sand (Sa) and gas concrete (GC)-based SWT facilities was later demonstrated in long-term experiments using laboratory packed bed reactors and field constructed filter beds. The efficacy of SaBC and GCBC systems in reducing turbidity (&gt;95%), DOC (60%; p&lt;0.05) and PO43- (40-90%; p&lt;0.05) was significantly higher than for their reference counterparts. Further, sorbed P was more leachable from Sa (11.2 mgkg-1) and SaBC (20.5 mgkg-1) filters but more extractable and hence plant-available in GC (65-91 mgkg-1). Therefore, the study concluded that fortification of soil-based systems with biochar filters may be a promising solution in enhancing performances of soil-based wastewater treatment systems, while P-rich RF media can act as a nutrient source for plants if recycled to agriculture. / <p>NB: Research Funder was: Botswana International University of Science and Technology, Botswana. QC 20170524</p>

Evaluating the performance of filter media for filtration applications is essential to assure design engineers and users that filter device will deliver promised performance for specific applications under the environmental stress. The study of particle loading characteristics of filter media in the laboratory setting is typically performed under the steady flow conditions, i.e., at the constant particle concentration and flow rate. In reality, filtration products are operated under the situations that the flow rate and mass concentration of particles are varied in time. The success of translating the laboratory data to estimate the performance of filter media in the fields is thus limited. It is necessary to investigate the performance of filter media under the real-world conditions, i.e., unsteady flow rate and mass concentration to bridge the gap. The overall goals of this research are (1) to study the performance of filter medium under unsteady conditions (i.e., the performance of respirator filter media under simulated breathing conditions); and (2) to investigate the issue of non-uniform particle deposition on HVAC filter panels. A new experimental setup was developed to accomplish the former goal. Numerical modeling tool, Computational fluid dynamics (CFD), was applied to achieve the latter objective……

The aim of this research was to find a suitable alternative medium of scarce freshwater for textile dyeing, and to recycle and reuse the dyebath using a combined coagulation/flocculation and novel filter media. Simulated seawater (SSW) was tested as the alternative dyeing medium with a salt concentration of 3.5% where NaCl was the major component. Fibre/dye systems of wool/acid and metal complex, wool/reactive, polyester/disperse, nylon/acid and metal complex, and acrylic/cationicdyes were tested in simulated seawater and the performances of dyed fabric were compared to conventional dyeing system of distilled water (DSW). The study found that commercial dyeing processes were robust and can be practically transferable into the seawater medium. The dye exhaustions, build-up, colour characteristics, and fastness to wash, cross-staining, rub and light were satisfactory within the dye ranges studied, which covers commercially available monochromatic Red, Yellow and Blue at light, medium and deep shades. Although SEM micrographs didn't show any presence of salt, a typical wash-off process of 1gL-1 with a non-ionic detergent at 70°C was sufficient to remove any salt that could be present on the surface or sub-surface of the dyed fabric. At room temperature, some acid and metal complex dyes were only partially soluble in SSW but this improved with gentle heating and addition of levelling agents. At dyeing temperatures near the boil, these dyes were completely soluble. A saturation limit was found to be existed for acrylic dyeing of cationic dyes over 1.0% o.m.f. depth. Although ionic interaction was the dominant mechanism for dyeing of wool, nylon and acrylic fibre with acid, metal complex and cationic dyes, the adsorption in highly saline dyebath most likely depended on the combined effects of ionic and physical/hydrophobic interaction. The resultant effect was higher dye exhaustion and consequently higher colour difference in SSW for some dyes. Reactive dyes were known to be sensitive to hardness of water but this study confirmed that reactive dye could be an alternative for deep dyeing for wool fibre in SSW. Reactive dyeing of wool followed a similar mechanism of gradual phase transfer as was observed for disperse dyeing of hydrophobic fibres over 3.0% o.m.f. depth. In contrast disperse dyeing of polyester produced consistent results for all dyes but some black dyeings produced superior colour strength in SSW. The build-up of colour in SSW compared to DSW can be different depending on the application level. To improve permeate flux by reducing membrane fouling, a number of surface modification were carried out to introduce fluorine based functional groups. Gaseous fluorination, fluorocarbon finish (FC) and plasma polymerisation were performed to introduce hydrophilic and oleophobic properties on supplied Azurtex membrane. The fluorinated Azurtex media exhibited increased wettability although it was not directly proportional to an increase in the fluorination level and treatment time. The water and oil repellency of FC and plasma treated filter media provided a reasonable level of repellency while the contact angle remained in the range of 130 to 145°. Pre-fluorination of filter media before FC treatment didn't change the water and oil repellency. Surface characterisation of Azurtex media was performed with ATR-FTIR, XPS and SEM. An increased level of fluorination at 10%F2 and prolonged exposure showed a degradation of the surface along with colour change. The fluorinated, FC treated and plasma polymerised membrane showed a typical C-F stretching vibration in the region of 1100-1350 cm-1 and weakly at 400-800cm-1. The XPS study showed a gradual increase in the -CF2 and -CF3 functionality signal intensities that resulted in imparting hydrophobicity The benchmarking of these modified Azurtex filter media against newly developed materials proved that plasma treatment improved the flow, reduced turbidity and provided an easy cake removal compared to fluorinated and FC finished filter media. Recycling of exhausted dyebath using a dual component coagulant/flocculant system of Pluspac 2000 and polyanionic Hydrosolanum protein derivative (HPSS) and microfiltration with Azurtex filter media was investigated. The process parameters such as pH and dosage of coagulants/flocculants were very critical during coagulation/flocculation for overall colour removal. The trial with model dye solution in SSW showed that the system worked in the saline environment with a relatively high concentration ratio of coagulant/flocculants but highly depends on the class and structure of dyes. Maximum colour removal was achieved for Lanaset Blue 2R and Sandolan Red MF-GRLN dye and was 89% and 61%, respectively, based on a ratio of 15:10 and 15:15 for PP2000: HPSS at pH 4.0 and 5.0, respectively. The reuse of the dyebath with combined physico-chemical and micro-filtration treatment was demonstrated to be feasible with wool/acid dye system. The colour profile of Lanaset Blue 2R and Sandolan Red MF-GRLN dyed fabrics up to 12th dyeing, with dyebath filtration undertaken after the 3rd /4th/5th reuse of the dyebath, remained comparable to dyeing in fresh baths. The colour strength, K/S, decreased after every filtration and the colour differences, DeltaE increased, but reversed in subsequent dyeing in reused dyebath. The wash and dry rub fastness of the dyed fabrics remained comparable and significant improvements in the abrasion resistance were observed.

The Central Queensland University developed an on-site wastewater treatment and reuse technology. Septic tanks were used for primary treatment and the discharged effluent was then pumped though a series of contained channels. The channels were designed to be a modified evapotranspiration trench; they were comprised of an aggregate layer and a soil layer in which were planted a variety of plants. The aggregate and the soil provided physical filtration, the microorganisms within the effluent, aggregate and soil provided nutrient reuse and transformation and the plants also used the nutrients and reused the treated effluent through evapotranspiration. Any effluent that was not transpired was returned to a holding tank and pumped through the evapotranspiration again. The treatment technology was assessed in relation to its ability to treat effluent in a sustainable manner. The water and soil was examined for concentrations of nutrients, heavy metals, salts, sodium, and organic carbon %. The pH, temperature and number of colony forming units of certain microorganism potential pathogens were also inspected in the soil and the water. The plants grown within the evapotranspiration channels were assessed in regards to their health, water usage, and in some cases potential pathogens on fruit. The infrastructure that was used to construct the wastewater treatment and reuse system was also evaluated in regards to reliability and maintenance. Certain limiting factors, in particular sodicity and salinity were identified, but the trial was successful and a sustainable form of on-site wastewater treatment and reuse technology was developed.