Potential Clogging Research Articles

Evolution of Pervious Concrete Pavement at the Ministry of Transportation Ontario, Canada

As part of the Ministry of Transportation Ontario (MTO) drive to pursue innovation and have the “greenest” roads in North America, MTO is actively pursuing the use of pervious concrete pavement. Pervious concrete provides many environmental benefits and is recognized as a stormwater management best practice. There is also strong interest from the Ontario municipal sector, conservation authorities and “green” innovators in rapidly incorporating pervious concrete into their designs. The Ministry is currently investigating and trying to address concerns with pervious pavement durability, the potential for clogging, impact of traditional winter maintenance practices and users’ acceptance of surface finish. The Ministry of Transportation Ontario (MTO) has completed two pervious concrete commuter parking lots and is currently working on a third. Field performance, construction practices and test methods are being studied for their effectiveness. Based on MTO experiences to date, an Ontario Provincial Standard Specification has been developed. This paper summarizes the construction observations, lessons learned and laboratory performance data from the Ministry’s work to date.

Automatic cleaning in acoustic ejection mass spectrometry: Enhancing the system robustness for large-scale high-throughput analysis of complex samples

The rapid evolution of high-throughput mass spectrometry (HT-MS) technologies has positioned MS as a pivotal analytical tool across diverse disciplines. Its significance is particularly pronounced in high-throughput drug discovery and development, where MS plays a critical role throughout various phases. Acoustic ejection mass spectrometry (AEMS) is a recent addition to the HT-MS landscape, showcasing a balanced performance high analytical throughput and high data quality. Particularly, AEMS's in-line dilution feature allows the direct analysis of large-scale, complex reaction solutions without the need for sample cleanup, making it a popular choice for large-scale high-throughput screenings. However, the substantial volume of complex matrix introduces concerns about system robustness, specifically regarding the potential clogging of the sample transfer line. This study addresses this challenge by introducing an integrated automatic washing feature to the AEMS system. This enhancement significantly improves system robustness without imposing any additional demands on assay execution time. Demonstrating an extended electrode lifetime, the cleaning approach proves effective in maintaining system performance over prolonged periods, showcasing its potential for continuous large-sample-scale high-throughput analysis applications.

Parametric modelling of clogging behavior of porous pavements with time

With the aim of facilitating easier development of guidelines for the stakeholders using porous pavements, a simple parametric mathematical model is developed for the prediction of clogging behavior, i.e., time-dependent decaying hydraulic conductivity of porous pavement dependent on two different input parameters in addition to time. Based on earlier experimental results, trends of diminishing hydraulic conductivities with time under different void ratios and particle sizes were established. It is found that for a particular particle size, the effect of void ratio on time-dependent hydraulic conductivity can be expressed with a combined linear and exponential functions. Again, for a particular void ratio, the effect of particle size on time-dependent hydraulic conductivity can be expressed with an exponential function. The particle size dependent equation was further extended to include the effect of void ratio through multiplying a linear function having void content as independent variable. Developed equation predicted results were compared with the original experimental measurements. It is found that all the three models are capable to well-predict experimental measurements with RMSE values equal or higher than 0.98. The void content dependent equation is capable to predict results having standard errors as, Root Mean Squared Error (RMSE) = 0.04, Mean Absolute Error (MAE) = 0.03 and Relative Absolute Error (RAE) = 0.09, whereas the same error statistics of the particle size dependent equation are 0.04, 0.02 and 0.08 respectively. Error statistics of the combined (particle size and void ratio) equation are, RMSE = 0.1, MAE = 0.07 and RAE = 0.22. Such modelling technique would be useful for the prediction of potential clogging in the porous pavement for any combination of input parameters.

Geochemical modeling of CO2 injection and gypsum precipitation at the Ketzin CO2 storage site

Gypsum crystals are found at the well perforation of observation well Ktzi 202 of the test site for CO2 storage at Ketzin, Germany. XRD analysis confirms pure gypsum. Fluid samples before and after CO2 injection are analyzed. Geochemical modeling is conducted to identify the mechanisms that lead to gypsum formation. The modeling is carried out with PHREEQC and Pitzer database due to the high salinity of up to 5 mol per kg water. Due to their significantly higher reactivity compared to other minerals like silicates, calcite, dolomite, magnesite, gypsum, anhydrite, and halite are considered as primary mineral phases for matching the observed brine compositions in our simulations. Calcite, dolomite, and gypsum are close to saturation before and after CO2 injection. Dolomite shows the highest reactivity and mainly contributes to buffering the brine pH that initially decreased due to CO2 injection. The contribution of calcite to the pH-buffering is only minor. Gypsum and anhydrite are no geochemically active minerals before injection. After CO2 injection, gypsum precipitation may occur by two mechanisms: (i) dissociation of CO2 decreases activity of water and, therefore, increases the saturation of all minerals and (ii) dolomite dissolution due to pH-buffering releases Ca2+ ions into solution and shifts the mass action to gypsum. Gypsum precipitation decreases with increasing temperature but increases with increasing partial CO2 pressure. Our calculations show that calcium sulfate precipitation increases by a factor of 5 to a depth of 2000 m when Ketzin pressure and temperature are extrapolated. In general, gypsum precipitation constitutes a potential clogging hazard during CO2 storage and could negatively impact safe site operation. In the presented Ketzin example, this threat is only minor since the total amount of gypsum precipitation is relatively small.

Clogging and Water Quality Change Effects of Typical Metal Pollutants under Intermittent Managed Aquifer Recharge Using Urban Stormwater.

Managed aquifer recharge (MAR) using urban stormwater facilitates relieving water supply pressure, restoring the ecological environment, and developing sustainable water resources. However, compared to conventional water sources, such as river water and lake water, MAR using urban stormwater is a typically intermittent recharge mode. In order to study the clogging and water quality change effects of Fe, Zn, and Pb, the typical mental pollutants in urban stormwater, a series of intermittent MAR column experiments were performed. The results show that the type of pollutant, the particle size of the medium and the intermittent recharge mode have significant impacts on the pollutant retention and release, which has led to different clogging and water quality change effects. The metals that are easily retained in porous media have greater potential for clogging and less potential for groundwater pollution. The fine medium easily becomes clogged, but it is beneficial in preventing groundwater contamination. There is a higher risk of groundwater contamination for a shallow buried aquifer under intermittent MAR than continuous MAR, mainly because of the de-clogging effect of porous media during the intermittent period.

CO2 Liquefaction Close to the Triple Point Pressure

For vessel-based transport of liquid CO2 in carbon capture and storage chains, transport at 8 bar(a) enable significant cost reductions compared to transport at higher pressures for most transport distances and volumes. Transport at even lower pressures could further reduce the costs. There are, however, concerns related to dry ice formation and potential clogging in parts of the chain that could lead to operational issues when operating close to the triple point pressure of CO2. In this paper, results from an experimental campaign to de-risk and gain operational experience from the low-pressure CO2 liquefaction process are described. Six experiments using pure CO2 or CO2/N2 mixtures are presented. In four of the experiments, the liquid product pressure was continuously lowered until dry ice was detected and eventually clogged the system. In the final two experiments, the liquefaction process was run in steady-state at low liquefaction pressures for five hours to ensure that there is no undetected dry ice in the process that could lead to accumulation and operational issues over time. These experiments demonstrate that pure CO2 can be safely liquefied at 5.8 bar(a) and a CO2/N2 mixture can be liquefied at 6.5 bar(a) without issues related to dry ice formation.

ADSORPTION STUDIES OF RHODAMINE B DYE FROM AQUEOUS SOLUTION USING ALKALINE MODIFIED BIOCHAR & NON MODIFIED BIOCHAR OBTAINED FROM THE PYROLYSIS OF MUNICIPAL SOLID WASTE

The aim of this research is to use Municipal Solid Waste (MSW) prepared from the pyrolysis at 450 ⁰C for the removal of cationic dye (Rhodamine B) in aqueous solution. The effects of contact time and reaction temperature were studied in a batch setup. Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) Spectroscopy were used to characterize the modified Biochar and non modified Biochar in order to predict the morphological properties and structural modification respectively. It was found that initial dye concentration (10mg/L), adsorbent dosage (0.3g) and contact time (100minutes) were found to give the highest removal of dye from the adsorbents. Subsequently, it was observed that an increase in the reaction parameters showed an increasing trend for the removal of dye. SEM analysis showed distinct morphology for the fresh and spent adsorbent which was linked to potential clogging resulting from uptake of pore sites by the dyes. The adsorption isotherms showed that the adsorption equilibrium data obeys Langmuir adsorption Isotherm with the maximum monolayer adsorption capacity of 20.30 mg/g and 20.23 mg/g and Pseudo Second Order kinetic model best described the experimental findings for the two adsorbents used in the study. Moreover, thermodynamic study reveals that the adsorption is a spontaneous and exothermic process

Clogging mechanisms and preventive measures in artificial recharge systems

Groundwater which occurs in fractured rock or porous aquifers or other geological weak zones such as faults and fractures is usually extracted via boreholes, hand wells or other sources such as springs. Water scarcity has become a severe problem due to many factors, such as an alarming increase in population and per capita water consumption, over exploitation of groundwater resources and abrupt global climatic change along with its related eco-environmental geological problems. In such situation, application of artificial recharge systems (e.g. surface recharge basin and deep injection well systems) can help to effectively manage and augment the unitization of groundwater resources. However, the clogging problem, which may be caused by a complex interdependent mechanisms of physical, chemical and biological has been a challenge for the efficacy and the implementation of recharge facilities. Clogging can reduce the permeability, recharge rate and longevity of recharge facilities and increase the operational and maintenance costs. Major influencing factors associated with the occurrence of clogging include the chemical composition of groundwater (both the recharge water and native groundwater), aquifer medium and microbial diversity, together with other environmental factors such as temperature, pressure, total dissolved solids, total soluble salts, pH, Eh, nutrients, gases, carbonates and others; these factors ultimately increase the piezometric head but reduce the permeability and infiltration rates of porous/seepage media. Pretreatment of recharge water can minimize the potential clogging. In the case of clogged wells, rehabilitation methods need to be deployed. In the meantime, there is an urgent needs to understand the basic causes and developmental processes/mechanisms of clogging in order to mitigate this problem. This paper reviews the major clogging mechanisms and their possible preventive measures and redevelopments in artificial recharge systems.

Assessment of Microirrigation Field Distribution Uniformity Procedures for Pressure-Compensating Emitters under Potential Clogging Conditions

HighlightsDistribution uniformity of the lower quartile (DUlq) was assessed in three microirrigation subunits with three procedures that used different locations and different numbers of sampled emitters.Using reclaimed effluent as the water source, performance was periodically measured for a total duration of 1000 h.Emitter clogging and the locations of sampled emitters greatly affected DUlq.None of the procedures accurately assessed DUlq if more than 4% of the emitters were fully clogged.Abstract. Proper water distribution uniformity is important for successful use of microirrigation systems. Consequently, consistent system monitoring and periodic distribution uniformity assessments can help determine the performance of a microirrigation system and identify possible problems that should be corrected. When using irrigation water with a greater clogging risk, such as reclaimed effluent, emitter clogging can seriously affect distribution uniformity. In this study, distribution uniformity was measured at three times (0 h, 500 h, and 1000 h of operation) in a microirrigation system that used reclaimed effluent. Emitter discharge values were obtained for each emitter in the system (three subunits consisting of four driplines each with 226 pressure-compensating emitters on each dripline), and the distribution uniformity of the low quartile (DUlq) was calculated for each subunit. These comprehensive DUlq values were compared with those calculated by three estimation procedures developed by Merriam and Keller, Burt, and Juana et al., which use different sampling locations and different numbers of sampling points. Results showed strong influence of emitter clogging and the location of the sampled emitters on DUlq values. Using this data set, the Merriam and Keller procedure had the greatest root mean square error (RMSE = 41.8%), the Burt procedure resulted in an intermediate value (RMSE = 5.9%), and the Juana et al. procedure had the lowest (RMSE = 3.2%) when most of the completely clogged emitters (about 1% of the total) were located at the ends of the driplines. Further speculative analysis in which complete clogging was allowed to migrate to the farthest distal emitters for the Burt and Juana et al. procedures indicated that none of the procedures accurately assessed the actual complete DUlq. These results suggest that none of these procedures alone are successful at assessing system-wide distribution uniformity when substantial clogging exists. Keywords: Drip irrigation, Effluent, Emitter clogging, Flow variation, Wastewater.

ОРГАНІЧНА СИСТЕМА ЗЕМЛЕРОБСТВА ТА ПРОПОЗИЦІЇ ДО ЇЇ РЕАЛІЗАЦІЇ

Organic system of farming (better called a biological system) is an alternative to the modern intensive systems, according to which the technology of cultivated crops involves the production of environmentally healthy food for the humans and feed for farm animals. To do this, crop products must not contain any harmful chemical residues. Therefore, the use of any artificial chemicals, for example, mineral fertilizers, herbicides, fungicides, insecticides, desiccants, defoliants, etc. is prohibited in its production. The area under the organic system is increasing from year to year and by 2018 they have reached 32.4 million hectares in the world, including 7.4 million hectares in Europe, and the leaders among European countries in the production of organic products are Austria and Switzerland. In 2011, the Verkhovna Rada of Ukraine adopted the Law “On Organic Production”, which defines the legal, economic, social and organizational bases of organic farming. However, the area under such a system in the country so far remains insignificant, and the reason for this is the high potential clogging of our lands, which does not allow the transition to herbicide-free technologies. Below are some techniques that allow you to reduce the clogging of the fields below the threshold of its harmfulness in order to abandon herbicides as a major factor in the deterioration of phytosanitary conditions. Such methods are such a structure of the sown areas, allowing to switch to crop rotation, application of manure without weed seeds, use of improved chills instead of the usual, inclusion in the technology of spring harrowing pre-emergence and their shoots, abandonment of intermediate cultivation for late spring crops instead of spring crops, use spring May.

Potential freshening impacts on fines migration and pore-throat clogging during gas hydrate production: 2-D micromodel study with Diatomaceous UBGH2 sediments

Abstract The methane gas hydrate stored in natural sediments is considered a potential gas resource. Countries such as China, India, Japan, and Korea are interested in commercializing this resource, and offshore field pilot tests for gas production have been conducted using depressurization methods to destabilize gas hydrate and facilitate the migration of methane to the production well. However, fine-grained sediments (fines), which are present even in coarse-grained, gas hydrate-bearing sediments, can be resuspended in the production fluid, subsequently clogging pore throats in the formation and reducing the overall production efficiency. We conducted laboratory tests to evaluate the suspension and clogging potential of fines collected from the Ulleung Basin, East Sea, Korea during the 2010 Ulleung Basin Gas Hydrate Expedition 2 (UBGH2). Experimental results reveal that diatoms are prevalent in the sediment and largely control the suspension and clogging behavior. Fluid flow experiments in 2D micromodels show clogging occurs even when injecting the minimum sediment concentration (0.1 wt% in the fluid) through micromodels with pore-throat widths at the high end of the anticipated range for UBGH2 gas hydrate-bearing sands (100 μm). Mobile gas/fluid interfaces forming during gas hydrate dissociation accentuate clogging by concentrating and mobilizing fines. Sedimentation tests show pore-water freshening during dissociation is not anticipated to change the potential for diatoms to become entrained in the pore water flow, even for the observed gas hydrate saturations of ~80%. Muscovite and illite are also significant components of the tested sediment, however, and pore-water freshening increases their potential for resuspension and clogging. Overall, the resuspension and clogging potential of these fine sediments should increase as gas hydrate dissociation progresses in the thin, gas hydrate-bearing sands investigated in the Ulleung Basin.

Efficacy of Spent Lime as a Soil Amendment for Nutrient Retention in Bioretention Green Stormwater Infrastructure

The composition of bioretention soil media (BSM) is among the most critical design attributes contributing to the water quality performance of bioretention systems, as various amendments may increase the capacity for chemical sorption of certain nutrient pollutants. We investigated the spent lime (a calcium-based water treatment residual) as BSM amendments for nutrient retention. The study was conducted in two parts: the first was a field-based mesocosm experiment in which we assessed the effect of spent lime amendments on leachate nutrient concentration for treatments receiving different levels of phosphorus and nitrogen loading (simulated by different levels of compost added to the substrate). The second was a laboratory study comparing various levels of spent lime and coir on leachate nutrient concentration at two different simulated loading rates. Effluent water was collected and analyzed for PO43−, NH4+ and NO3− concentrations in the field and lab. Spent lime significantly reduced leachate PO43− concentrations (upwards of 50%) in both the field and lab mesocosm studies compared to treatments without spent lime. Reductions in NH4+ concentrations were also observed due to spent lime but with variable significance across the different compost levels, whereas NO3− concentrations were higher in plots with spent lime than plots without spent lime. In the lab, columns with coir had significantly higher leachate PO43− concentrations compared to spent lime-treated columns, however, leachate NH4+ and NO3− concentrations did not significantly differ between treatments at the same compost levels. This study shows that spent lime, which is a waste product, is effective in significantly reducing leachate PO43− concentrations from BSM, while be a cost-effective substitute to engineered proprietary media that is expensive to acquire; however, future studies must also evaluate its potential for clogging.

Assessment of the clogging potential of two clays

Clogging sometimes occurs in tunnelling projects. Soils containing high plasticity clay minerals have a high potential for clogging. To gain a better understanding of the effect of swelling clay on the clogging potential, two different clays, bentonite and kaolin, were tested in different proportions. Several approaches were employed to evaluate clogging potential, including a semi-empirical diagram, laboratory-based drilling tests, and evaluation of the variation of the plasticity indexes. The performance of an additive was also evaluated using the same method as for pure mixtures. To determine the correlation between the mechanical properties and clogging potential of the mixtures, vane shear tests were carried out on the mixtures containing the additive. The results revealed that mixtures with bentonite had a higher clogging potential than pure kaolin. The performance of additives used for mitigation of clogging also changed with the content of bentonite in the mixtures. The simple drilling tests were capable of quantitatively differentiating the clogging potential of plain mixtures and evaluating the performance of additives.

Valorisation of olive mill wastewater by phenolic compounds adsorption: Development and application of a procedure for adsorbent selection

A procedure for the selection of the optimal adsorbent for phenolic compounds (PC) recovery from PC-rich wastes and wastewaters was innovatively proposed and applied to compare 4 neutral resins (Amberlite XAD16N, Optipore SD-2, Amberlite FPX66, Amberlite XAD761) and 1 ion-exchange resin (Amberlite IRA958 Cl) for PC recovery from a Tunisian olive mill wastewater (OMW). In the initial batch isotherm tests a neutral resin (XAD16N) performed best thanks to its high PC sorption capacity (81 mgPC/gdry resin) and PC content in the sorbed product (0.19 gPC/gvolatile solids). Also ion-exchange resin IRA958, used in OH form in this work, resulted interesting thanks to its satisfactory performances and very low cost (8 €/L). These two pre-selected resins were further compared by means of continuous-flow adsorption/desorption tests conducted in a 1-m packed column. The results indicate that if a low (20%) breakpoint is selected, XAD16N leads to a PC-richer sorbed product (0.14 gPC/gvolatile solids) and a higher operating capacity (0.30) than IRA958. Conversely, if a very high (90%) breakpoint is selected, the two resins produce similar desorbed products in terms of both PC content (0.19–0.21 gPC/gvolatile solids) and antioxidant capacity (4.6–4.9 gascorbic acid equivalent/gPC). Resin-specific dynamic desorption procedures led to very high PC desorption yields (87–95%). The identification of the actual PCs present in the final desorbed product indicated for XAD16N a higher capacity to preserve the integrity of the PC mixture of the studied OMW. OMW microfiltration (0.2 μm pore-size) led to a 99.8% suspended solid removal – thus protecting the packed column from potential clogging – with a very low PC loss.

Groundwater quality assessment and its suitability for agricultural purposes in the Behbahan Plain, SW Iran

Abstract Groundwater is the main agricultural water resource in arid and semi-arid regions, so, preserving it is extremely important. In this study, groundwater quality was assessed for irrigation, using the principal chemical and physical quality parameters from 30 wells in the study area. Groundwater classification on the basis of electrical conductivity reveals that more than 85% of the samples taken fall into the ‘unsuitable’ and ‘doubtful’ classes. On the basis of Richards's classification, 67% of the samples are unsuitable for irrigation. Most, however, appear suitable for irrigation based on their sodium adsorption ratio, %Na, permeability index, magnesium adsorption ratio, Kelly's ratio and residual sodium carbonate water quality indices. The concentration of boron varies between 0 and 2 mg/l, within the FAO's (Food and Agriculture Organization of the United Nations) acceptable standard range. About 60% of the wells are not suitable for drip irrigation because of the water's potential for clogging. There will be no water infiltration problem, if groundwater in the study area is used for irrigation. With respect to the SO42− and Cl− concentrations, 53% and 13% of the samples collected are unsuitable for irrigation, respectively. Less than 10% of the samples have ‘severe’ constraints restricting their use for irrigation with respect to nitrogen. For sprinkler irrigation, however, the groundwater is subject to ‘severe’ restrictions. Geochemical investigations indicate that the water chemistry is affected by processes including evaporation, water-rock interactions and human activities.

Influence of hydraulic loading rate on ion precipitations and performance of a vertical-flow soil filter treating contaminated groundwater under cold climatic conditions

Long-term investigations were carried out in a pilot-scale vertical-flow soil filter (VFSF) system to characterize the fate of different precipitating ions (Fe2+, Mn2+, Ca2+) during the remediation of heavily contaminated groundwater under different hydraulic loading rates (HLRs) and to assess MTBE and BTEX removal efficiencies under low winter temperatures. Two specially designed VFSF, a roughing filter (RF) packed with expanded clay material (grain size: 3–6mm) and a polishing filter (PF) with zeolite material (grain size: 0–5mm) were operated in both single-stage and two-stage configuration. During single-stage operation, a stepwise increase of HLRs from 60 to 120, 240, 480Lm−2 d−1 in both RF and PF were applied. During two-stage operation, a highly efficient Fe2+ removal with a mean removal efficiency of 99% was already observed in the effluent of the first treatment step (RF; HLR=960Lm−2 d−1) and protected the second filter (PF; HLR=480Lm−2 d−1) from potential clogging due to iron hydroxide precipitates. The removal of Ca2+ decreased remarkably from 28% to 7% in the RF and from 54% to 10% in the PF as the HLR increased stepwise in single-stage operation. During two-stage operation with a high HLR in the RF resulted in only 3% removal of the mean Ca2+ inflow concentration (211±18mgL−1). This clearly showed that at high HLR, Ca2+ was rapidly flushing out of the VFSF system instead of carbonate precipitations and proved to be very effective to protect the filter from potential clogging. During winter, when daily mean outside air temperature was as low as −20°C, a relatively low water temperature in the range of 5.1–8°C in the effluent and a low MTBE and benzene mean removal rate of 0.41±0.07 and 2.08±0.33gm−2 d−1, respectively, was observed at a low HLR (120Lm−2 d−1). Whereas, at a high HLR (960Lm−2 d−1), a mean temperature of 13.0±1.3°C was maintained inside the filter resulting in a high MTBE and benzene removal rate of 2.37±0.02 and 14.41±0.65gm−2 d−1, respectively. Our results with high removal efficiencies for MTBE and benzene together with highly efficient Fe2+ and Mn2+ removal suggest that a two-stage VFSF can be a very promising technology for the remediation of heavily contaminated groundwater in oil and gas industries. Furthermore, it was shown that at high HLRs, filter clogging due to Ca-precipitation was prevented and treatment efficiency was not affected even under cold climate conditions with atmospheric air temperature as low as −20°C.

Copper precipitation as consequence of steel corrosion in a flow-through experiment mimicking a geothermal production well

Decreasing production rates and massive precipitation of native copper (Cu(0)) were observed in the production well at the geothermal research facility Groß Schönebeck (Germany). The Cu precipitates filling up the well are a product of an electrochemical corrosion reaction between dissolved copper (Cu2+, Cu+) in the brine and iron (Fe(0)) of the carbon steel liner. It was hypothesized that this reaction occurs not only within the borehole, but also on the outside of the casing at contact between casing and reservoir rock as well as in the pores of the reservoir rock. To verify the assumption of potential clogging of the rock pores as well as to quantify the reaction and to determine reaction kinetics, a flow-through experiment was designed mimicking the reaction at depth of the well between sandstone samples (24 cm3 Fontainebleau), steel (carbon steel or stainless steel), and artificial formation water containing 1 mM Cu2+ at oxic or anoxic (O2 < 0.2 mg/L) conditions in dependence of temperature and salinity. Obtained experimental data served as input for a numerical reaction model to deepen the process understanding and that ultimately should be used to predict processes in the geothermal reservoir. Results showed that (1) with increasing temperature, the reaction rate of the electrochemical reaction increased. (2) High amounts of sodium and calcium chloride (NaCl + CaCl2) in the solution decreased the overall reaction inasmuch more Fe and less Cu was measured in the salt-poor solutions over time. (3) Strongest oxidation was observed in oxic experiments when not only native copper but also iron hydroxides were identified after the experiments in the pore space of the rock samples. (4) No reaction products were observed when stainless steel was used instead of carbon steel to react with the Cu2+ solution. A numerical flow-through reactor model was developed for PHREEQC based on the assumption that Fe(0) corrosion is kinetically controlled and subsequent Cu(0) precipitation occurs in thermodynamic equilibrium within the investigated experimental set-up. Calculated coefficients of determination comparing measured and simulated reaction rates for Fe and Cu underline the validity of the approach.

Towards a robust assessment of bridge clogging processes in flood risk management

River managers are aware that wood-clogging mechanisms frequently trigger damage-causing processes like structural damages at bridges, sudden channel outbursts, and occasionally, major displacements of the water course. To successfully mitigate flood risks related to the transport of large wood (LW), river managers need a guideline for an accurate and reliable risk assessment procedure and the design of river sections and bridges that are endangered of LW clogging.In recent years, comprehensive research dealing with the triggers of wood-clogging mechanisms at bridges and the corresponding impacts on flood risk was accomplished at the University of Innsbruck. A large set of laboratory experiments in a rectangular flume was conducted. In this paper we provide an overall view of these tests and present our findings. By applying a logistic regression analysis, the available knowledge on the influence of geometrical, hydraulic, and wood-related parameters on LW clogging probabilities is processed in a generalized form. Based on the experimental modeling results a practice-oriented guideline that supports the assessment of flood risk induced by LW clogging, is presented. In this context, two specific local structural protection measures at the bridge, aiming for a significant decrease of the entrapment probabilities, are illustrated: (i) a deflecting baffle installed on the upstream face of the bridge and (ii) a channel constriction leading to a change in flow state and a corresponding increase of the flow velocities and the freeboard at the bridge cross section.The presented guideline is based on a three-step approach: estimation of LW potential, entrainment, and transport; clogging scenario at the bridge; and the impact on channel and floodplain hydraulics. For a specific bridge susceptible to potential clogging caused by LW entrapment, it allows for a qualitative evaluation of potential LW entrainment in the upstream river segments, its transport toward the hydraulic bottleneck, and for a quantification of expected entrapment probabilities. Depending on the amount and characteristics of the impacting LW, consequences of bridge clogging can be determined and LW bridge-clogging scenarios can be considered within hydrodynamic numerical modeling.

A high-throughput microfluidic approach for 1000-fold leukocyte reduction of platelet-rich plasma.

Leukocyte reduction of donated blood products substantially reduces the risk of a number of transfusion-related complications. Current ‘leukoreduction’ filters operate by trapping leukocytes within specialized filtration material, while allowing desired blood components to pass through. However, the continuous release of inflammatory cytokines from the retained leukocytes, as well as the potential for platelet activation and clogging, are significant drawbacks of conventional ‘dead end’ filtration. To address these limitations, here we demonstrate our newly-developed ‘controlled incremental filtration’ (CIF) approach to perform high-throughput microfluidic removal of leukocytes from platelet-rich plasma (PRP) in a continuous flow regime. Leukocytes are separated from platelets within the PRP by progressively syphoning clarified PRP away from the concentrated leukocyte flowstream. Filtrate PRP collected from an optimally-designed CIF device typically showed a ~1000-fold (i.e. 99.9%) reduction in leukocyte concentration, while recovering >80% of the original platelets, at volumetric throughputs of ~1 mL/min. These results suggest that the CIF approach will enable users in many fields to now apply the advantages of microfluidic devices to particle separation, even for applications requiring macroscale flowrates.

Use of Dehydrated Agar to Estimate Microbial Water Quality for Horticulture Irrigation.

Petrifilms are dehydrated agar culture plates that have been used to quantify colony forming units (CFU) mL of either aerobic bacteria (Petrifilm-AC) or fungus (Petrifilm-YM), depending on substrate composition. Microbes in irrigation systems can indicate biofilm risk and potential clogging of irrigation emitters. The research objective was to compare counts on Petrifilms versus traditional, hydrated-agar plates using samples collected from recirculated irrigation waters and cultures of isolated known species. The estimated count (in CFU mL) from a recirculated irrigation sample after 7 d of incubation on Petrifilm-YM was only 5.5% of the count quantified using sabouraud dextrose agar (SDA) with chloramphenicol after 14 d. In a separate experiment with a known species, Petrifilm-YM did not successfully culture zoospores of . Isolates of viable zoospores were cultured successfully on potato-dextrose agar (PDA), with comparable counts with a vegetable juice medium supplemented with the antibiotics pimaricin, ampicillin, rifamycin, pentochloronitrobenzene and hymexazol (PARP-H). The quantification of pv. Begoniaceae on Petrifilm-AC was not significantly different ( < 0.05) than on PDA, but was lower than on Reasoner and Goldrich agar (R2A) or with a hemocytometer. The current formulation of Petrifilm-YM is unlikely to be a useful monitoring method for plant pathogens in irrigation water because of the inability to successfully culture oomycetes. However, Petrifilm-AC was an effective method to quantify bacteria and can provide an easy-to-use on-farm tool to monitor biofilm risk and microbial density.