Bench-scale Tests Research Articles

Advanced reclamation of hairwork dyeing effluent using tree-shaped cellulose flocculants and subsequent optimization of dual-membrane performance and fouling behavior

The purpose of this study is to prepare eco-friendly cationic tree-shaped cellulose-based flocculants (CLFs) through ultrasonic modification as the primary pretreatment, and then realize advanced hairwork dyeing effluent (HDE) reclamation by coupling with dual membrane process. The results showed that the optimal CLF-10 could be obtained by extra ultrasonic processing with a certain conservative time to tune its microstructure appearing in a well-veined and fluffy tree-shaped morphology with relatively uniform particle size distribution. The excellent flocculation performance of CLF-10 in terms of turbidity, total organic carbon (TOC) and dissolved organic carbon (DOC) removal rates reached up to 99.1%, 72.1% and 70.5% at the dosage of 100 mg L−1, and the largest and most dense flocs (Amean of 269 900 μm2 and Df of 1.80) were formed accordingly. This is precisely because the above mentioned microstructure properties enable it to have smaller steric hindrance effect and more active sites, thus effectively clustering the largest amount of target contaminants. Consequently, the bench-scale test employed CLF-10 agent achieved a higher HDE recovery rate of 80.3% under the circumstance of lower operating pressure and significantly mitigated membrane fouling, and the final cleaner reuse water only contained 76.2 mg⋅L−1 of total dissolved solids (TDS), 23.9 mg CaCO3·L−1 of total hardness and 1.85 mg·L−1 of DOC.

Validation of pyrolysis model in transient heating scenarios and diverse spectral boundary conditions

This study aims to provide a robust validation to the condensed-phase pyrolysis model approach used in the FireFOAM CFD code. Firstly, bench-scale pyrolysis tests were conducted for two engineering wood products (EWPs), namely plywood and medium density fiberboard (MDF), at three constant heat flux levels. These tests were used to derive model-effective material properties via inverse modeling and optimization approaches. For MDF, a better model fit was obtained when the virgin material density was allowed to vary along its thickness, which is consistent with its known anisotropic nature. Next, three test cases were developed for the purpose of pyrolysis model validation by subjecting the EWPs to fire-relevant dynamic heating scenarios. In two tests, the materials were exposed to transient heating conditions where the heat flux to the materials increased over the duration of pyrolysis. In the remaining test, the spectral emissivity boundary condition of the sample material was altered significantly. Very good agreement was observed between the validation experimental data and the model predictions for all three scenarios. The validation studies provide confidence that the model-effective material properties, determined using inverse modeling and optimization for constant heating conditions, can be confidently applied to fire-relevant dynamic heating scenarios and boundary conditions.

Biological pretreatment: An innovative approach to addressing taste and odor

AWWA Water ScienceVolume 2, Issue 3 e1184 CORRIGENDUMFree Access Biological pretreatment: An innovative approach to addressing taste and odor This article corrects the following: Biological pretreatment: An innovative approach to addressing taste and odor Jess Brown, Jennifer Nyfennegger, Yong Ang, Mark Simpson, Bruce MacLeod, Olga Wolanin, Katherine Gilmore, Volume 2Issue 2AWWA Water Science First Published online: March 9, 2020 First published: 24 June 2020 https://doi.org/10.1002/aws2.1184AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat In Brown et al., 2020, the authors would like to recognize the two individuals who lend their technical knowledge to this article. Below is the revised Acknowledgement section: The authors thank Chance Lauderdale (formerly with Carollo, now with HDR) and Bob Cushing (Carollo) for important technical input on this work; Chance's Master's research help set the stage for the bench-scale testing. The authors also thank James Barazesh (Carollo Engineers, Inc.) for his invaluable assistance with data analysis and development of figures for this manuscript. REFERENCE Brown, J., Nyfennegger, J., Ang, Y., Simpson, M., MacLeod, B., Wolanin, O., & Gilmore, K. (2020). Biological pretreatment: An innovative approach to addressing taste and odor. AWWA Wat Sci., 2(2), e1173. https://doi.org/10.1002/aws2.1173Wiley Online LibraryCASGoogle Scholar Volume2, Issue3May/June 2020e1184 ReferencesRelatedInformation

Heat transfer mechanism of concurrent flame spread over rigid polyurethane foam: Effect of ambient pressure and inclined angle

As a common building façade insulation material with numerous applications, the heat transfer mechanism and flame spread characteristics of rigid polyurethane (RPU) foam should have been concerned. This work aims to give a comprehensive understanding of the coupling effect of sample inclination and ambient pressure on the heat transfer process and flame spread behaviors over RPU foam. A series of contrastive bench-scale tests were performed, in which inclination (denoted θ, 10°–90°) and ambient pressure (P, 65.5 and 100.8 kPa) were varied, and the variation of flame spread rate, flame length and flame stand-off distance were thoroughly investigated. Under the competitive effect of gas-phase heat transfer and surface charring, the extinction phenomena of flame spread were found, and the critical extinction angle were: θcrit,max=85∘, P = 100.8 kPa; θcrit,max=60∘, θcrit,min=25∘, P = 65.5 kPa. Based on the laminar and turbulent flow states, a piece-wise correlation to evaluate flame spread rate was established, which matched the experimental results well. Moreover, spreading flames were classified as pool-like flame and wall-like flame, and a new modified dimensionless correlation and semi-empirical model were proposed to describe the variation of flame length. Average flame stand-off distance was found to linearly decrease with inclination, y‾~θ, and the slopes in the plain and on the plateau were −0.455 and −0.776, respectively. The results of this study can provide a better insight for the fire safety design of energy conservation system of high-rise buildings.

Effect of H2O2 and potassium amyl xanthate on separation of enargite and tennantite from chalcopyrite and bornite using flotation

Effect of oxidation treatment using hydrogen peroxide (H2O2) on the floatability of copper sulfide minerals (i.e., chalcopyrite and bornite) and arsenic-bearing copper minerals (i.e., tennantite and enargite) is reported in this study. Pure mineral flotation shows that the floatability of each mineral significantly decreases after the oxidation treatment. Interestingly, flotation of mixed mineral of copper sulfide and arsenic-bearing copper minerals shows that enargite and tennantite exhibit a higher floatability compared to chalcopyrite and bornite after the oxidation treatment followed by the addition of potassium amyl xanthate (PAX). These flotation results indicate a possibility for selective flotation of copper sulfide and arsenic-bearing copper minerals. Indeed, bench-scale flotation tests show that the oxidation treatment using H2O2 and the addition of PAX can deliver a satisfying separation of copper sulfide and arsenic-bearing copper minerals. Difference oxidation products (i.e., CuO, Cu(OH)2, CuSO4, FeOOH, and Fe2(SO4)3) on each mineral surface are likely the cause of this different flotation behavior. Furthermore, these oxidation products may affect the adsorption amount of PAX on each mineral. Indeed, the adsorption tests show that PAX is adsorbed more on tennantite, bornite, and enargite compared to chalcopyrite owing to the formation of CuSO4 and Cu(OH)2 on the mineral surfaces under oxidizing conditions. A possible mechanism is proposed in this study to explain the selective flotation behavior of mixed minerals.

In-Can vitrification of ash

The In-Can Melter is a metallic crucible heated in a refractory furnace using electrical resistors allowing in-container vitrification. The In-Can Melter trial aims to demonstrate the feasibility of the confinement in a glassy matrix of ash coming from existing incineration processes. The ash was pelletised to allow its introduction into the can without dust emissions and then incorporated in a 50 wt.% waste loading confinement matrix. The full-scale trial was preceded by laboratory- and bench-scale tests. The microstructure and chemical durability of the wasteform were characterised.

A prediction method to evaluate thermal performance of protective clothing based on the correlation analysis of the bench scale and flame manikin tests

PurposeBench scale and flame manikin tests are two typical methods to evaluate thermal protective performance (TPP) of fire protective clothing. However, flame manikin test is limited to be widely used for its complication and high cost. The purpose of this paper is to develop a method to evaluate the thermal performance of protective clothing from the bench scale test results and garment parameters, which predicts the body burn injuries without conducting flame manikin tests.Design/methodology/approachBench scale and flame manikin tests’ data were collected from the previous research literature and then statistical analysis was performed to quantitatively investigate the correlations between the two test methods. Equations were established to predict the TPP values accounting for the effects of entrapped air gap and thermal shrinkage. Fitting analysis was conducted to analyze the relationship between the predicted TPP values and total burn injury. Finally, a method to predict total burn injury from the TPP values was proposed and validated.FindingsThe results showed that when the TPP value was predicted with the effects of air gap and thermal shrinkage considered, there was an approximate linear relationship between the predicted TPP values and total burn injury from the manikin test. Therefore, the prediction model of burn injury was developed based on the correlation analysis and verified with a generally good accuracy.Originality/valueThis paper presented a new prediction method to evaluate the thermal performance of protective clothing, which saved significant time and cost compared to the conventional methods. It can provide useful information for burn injury prediction of protective clothing.

Nitrite-shunt and biological phosphorus removal at low dissolved oxygen in a full-scale high-rate system at warm temperatures.

This study presents results from the City of St. Petersburg's (Florida) Southwest Water Reclamation Facility. This high-rate BNR plant (SRT~5days; HRT<8hr) achieves combined bioP and shortcut simultaneous nitrification and denitrification (SND) via nitrite in a simple BNR configuration-an anaerobic-aerobic (A/O) process without mixed liquor recycle and a 25% unaerated fraction. N removal to low effluent and nitrate and nitrite ( + ) concentrations occurs mainly via SND by operating the aerated zone at low DO, but still achieving near-complete ammonium ( ) removal. Despite the low DO operation, very good bioP performance is achieved. Full-scale performance data and detailed bench-scale testing were conducted to assess the nitrogen and phosphorus removal at low DO conditions. Full-scale results showed that the plant achieves effluent total inorganic nitrogen (TIN) and total phosphorus (TP) concentrations of approximately 2.0mgN/L and 0.5mgP/L, respectively, at an average influent C:N ratio of 7:1 mgCOD:mgN. PRACTITIONER POINTS: Simple anaerobic-aerobic (A/O) process demonstrated combined N and P removal Ammonia oxidation was not hampered by low DO (<0.5mg/L) operation Low DO (<0.5mg/L) operation sustained SND via nitrite pathway in a high-rate process (HRT<6hr) P uptake was demonstrated at low DO which counters to the widely held understanding that high DO (>1.5mg/L) is necessary Heterotrophic consumption of nitrite at low DO was the key to the out-selection of nitrite-oxidizing bacteria.

Filter Backwash Water and Floated Residue Containing Pathogenic Protozoa: Detection Method and Treatment Alternatives

Treatments using ozone for filter backwash water (FBW) and calcium oxide for floated residue (FR) were evaluated adopting bench-scale testing for the inactivation of Giardia spp. cysts and Cryptosporidium parvum oocysts. The protocol chosen for protozoa detection involved following the concentration step by direct centrifugation (adding ICN 7X cleaning solution at 1.0%) and purification by immunomagnetic separation (IMS). The FR treatment with calcium oxide (dosage of 23 mg CaO 100 mL−1 and 3-day contact time at 25 °C) proved to be efficient, as no parasites were detected after the treatment. The reduction of calcium oxide dosage (16 mg CaO 100 mL−1 and 3-day contact time at 25 °C) was insufficient to inactivate the protozoa, since potentially viable organisms were identified using propidium iodide (PI). Concerning the disinfection conditions with ozone (5-min and 10-min contact time and dosage of 10 mg O3 L−1 and 7.5 mg O3 L−1, respectively), there was complete removal of the target organisms, as no protozoa were detected after the FBW treatment. From the results obtained, the tested treatments can be considered promising alternatives for water treatment plants (WTPs). However, the costs incurred from these treatments have to be considered.

Fast-Track in Stream Action to Enhance the Oxidative Capacity within Watershed

This work presents a non-conventional alternative for cleaning polluted agriculture drainage network within a certain watershed. In Egypt, a need for using marginal quality water in agriculture applications is becoming a great necessity due to water shortage. One important strategy to increase available water resources is to reuse agriculture drainage water for irrigation application. The water system, especially drainage network receives a remarkable amount of pollution (raw and partially treated wastewater). That results to an increase in organic load to an unacceptable level, accordingly, the water quality of the drainage water has been negatively affected and the "reuse" plan has been threatened. Fast-Track In-stream Action (FTIA) is an ongoing fast action suggested to control the pollution of drainage water within a certain watershed to make it more suitable for reuse practice. FTIA as a quick interfere will skip long-term processes of conventional water treatment stages to get satisfactory results in proper time. It presents a practical immediate solution to achieve acceptable level of water quality rather than waiting for full improvement through long-term and expensive conventional programs. In this study a biological maintenance solution was applied and tested in both bench and field scales to assess its efficiency in improving the water quality within selected watershed. An evaluation of this fast-track process was done by measuring a significant key water quality parameters (WQPs) at designed locations of the study area before, during and after application of material. For better explanation of overall water quality and proper comparison, a weighted arithmetic water quality index (AWQI) has been discussed based on eight selected WQPs. In addition to a bench-scale test, two other field investigations were adopted: the first one investigates the effects of fast-track resources when applying the bio-based material under high flow condition with intermediate shock flow (study area "1"), while the other one examine the application of material under low flow condition with intermediate shock pollution load (study area "2"). All indicators, including aesthetics showed improvements in selected WQPs and AWQI during the investigation period

The Behaviour of Mixtures of Sodium Iso-Butyl Xanthate and Sodium Di-Ethyl Dithiophosphate during the Flotation of a Cu-Ni-Pt Ore in Degrading Water Quality

The use of mixtures of thiol collectors is reportedly beneficial in sulfide flotation. This is becoming standard practice for many concentrators, but process water recirculation and re-use in flotation circuits may compromise the behaviour of such mixtures owing to changes in physicochemical interactions occurring in the pulp phase as a result of water quality variations. It is expected that changes in the pulp chemistry would in turn affect both the pulp and froth phase phenomena, thereby affecting flotation performance. Thus, this study considers mixtures of thiol collectors, sodium iso-butyl xanthate (SIBX), and sodium di-ethyl dithiophosphate (SEDTP) in degrading water quality. Bench-scale flotation tests were conducted on various molar ratios of the selected thiol collectors under different ionic strengths (0.0242 mol·dm−3 and 0.1212 mol·dm−3) of synthetic plant water. Increasing the ionic strength of synthetic plant water and SEDTP molar ratio resulted in an increase in water, solids, Cu, and Ni recoveries. Cu-Ni grades decreased in increasing SEDTP molar ratios. The highest Cu-Ni grades were obtained in degrading water quality. The increase in water and solids recoveries in increasing SEDTP and ionic strength of plant water is attributed to an increase in froth stability. It can be concluded that the increase in the ionic strength of plant water increased water recoveries and therefore froth stability in parallel with SEDTP’s froth stabilizing effect, thus suggesting an additive interaction on the froth stabilisation effect seen.

Assessing structural reliability using real-time hybrid sub-structuring

While numerical simulations can be used to predict the dynamic performance of structural systems, there are some instances where the dynamical behaviour and uncertainties of specific system components may be difficult to accurately model. In these instances, structural reliability assessments may be conducted by employing the cyber-physical real-time hybrid sub-structuring (RTHS) test method. In this approach, a numerical model of a larger structural system, incorporating uncertainty in specific parameters, is coupled with a physical test specimen of a system component to fully capture system-level dynamic interactions and facilitate uncertainty propagation. This paper specifically details a study performed to experimentally validate the previously proposed adaptive Kriging-Hybrid simulation (AK-HS) structural reliability method. The AK-HS method combines Kriging metamodeling, an adaptive learning algorithm, Monte Carlo simulation, and RTHS testing to iteratively estimate a structural system's probability of failure given random parameters in the numerical model. The method is validated with a series of bench-scale RTHS tests on a viscous damper connecting two adjacent 6-degree-of-freedom rigid body structures. The AK-HS method is shown to accurately predict probabilities of failure for systems with up to 24 random variables using a reasonable number of RTHS tests.

Online ore monitoring using EDXRF method on process conveyor belts at Kazakhmys Corporation LLC operations

The paper discusses organizing online ore monitoring on process conveyor belts at the operations of Kazakhmys Corporation LLC using EDXRF method implemented as an ore-controlling station (OCS) targeting ore size of -300 mm. OCS is supposed to achieve the objective of providing reliable silver detection measurements in the range of 1+ ppm. Objects of monitoring: copper-containing polymetallic ores delivered to Zhezkazgan, Balkhash and Karagaily processing plants for treatment (target elements include copper, zinc, lead, silver, cadmium, and iron) as well as ores transported by the main underground feeder belt at Nurkazgan Mine (copper, zinc, lead, silver, molybdenum, and iron). The ultimate of the studies was to produce an online report on quality and quantities of ore and metals delivered from each of ore suppliers; to adjust the tonnages dispatched by the various shafts and open pits in the online mode; obtain reliable proof for unbiased redistribution of metals back to the mining operations. Equipment used during the studies: EDXRF OCS RLP21T. Key features of the unit are also discussed. The results of bench-scale testing as well as industrial application of OCS RLP-21T are discussed leading to the conclusion of successful online monitoring of silver in ores sized from +1 ppm to -300 mm. The photographs were provided by S. A. Yefimenko.

Bench-scale experimental tests and data analysis on CO2 capture with potassium prolinate solutions for combined cycle decarbonization

The present research work provides a quantitative evaluation of the CO2 absorption performance of potassium prolinate by setting a reliable and cost-effective approach for solvent screening, based on both experimental activities and data analysis. Potassium prolinate has been chosen as a promising green solvent to be tested at two different concentrations (30% and 43.38% w/w ProK aqueous solutions).The applied methodology involves direct comparison of the alternative solvent against a reference case, such as 30% w/w MEA solution. The test has been carried out on a bench-scale facility composed of a glass column with internal random packing located at Sotacarbo Research Center (Sardinia); the facility has been run in open and closed cycle mode, assessing the performance in terms of CO2 removal from NGCC synthetic flue gases (e.g.: 4% mol/mol CO2 concentration).The outcome of this work provides new information based on experimental data on removal, maximum achievable loading, loading increment rate and solvent capacity, and it constitutes a novel contribution to the literature. Moreover, it represents a tangible effort in delivering an insight on non-precipitating amino acid viability for flue gas decarbonization in CCS technologies.

Experimental investigation and numerical simulation of the combustion of flexible polyurethane foam with larger geometries

Numerical modelling of the combustion of flexible polyurethane foam (FPUF) is challenging, as the structural collapse and shrinkage of the foam complicate its pyrolysis, and two fuel items are involved in the combustion. Two-layer pyrolysis models were established based on the bench-scale tests over the past decade, but the accuracy was limited when simulating the combustion of FPUF with larger geometries. To improve the accuracy of the numerical simulation, small-scale experiments were conducted to investigate the combustion of FPUF with a larger geometry. Firstly, numerical simulations using a two-layer pyrolysis model proposed in the most recent research were performed to simulate the combustion of FPUF in the small-scale experiments. It was found that the heat release rate (HRR) was over-predicted in the initial combustion stage. Subsequently, based on the analysis of the visual and measured data obtained from the small-scale experiments, a three-layer model was proposed to describe the pyrolysis of FPUF in flaming combustion. The three-layer model was validated with the comparison of the predicted and experimental data. The results indicate that the numerical simulation using the three-layer model has a better performance in replicating the combustion of FPUF under well-ventilated conditions. While, the capability of the three-layer model was limited when it was used to simulate the combustion of FPUF in under-ventilated conditions, as it is found that ventilation influences the HRR of FPUF to a significant extent.

Pressure drop calculation for fly ash slurry using rheological model

Purpose This paper aims to the transportation of high concentration slurry through pipelines that will require thorough understanding of physical and rheological properties of slurry, as well as its hydraulic flow behavior. In spite of several contributions by the previous researchers, there is still a need to enrich the current understanding of hydraulic conveying through pipeline at various flow parameters. The pilot plant loop tests, particularly at high concentrations, are tedious, time-consuming and complex in nature. Therefore, in the current research the prediction methodology for slurry pipeline design based on rheological model of the slurry is used for calculation of pressure drop and other design parameters. Design/methodology/approach It has been established that slurry rheology plays important role in the prediction of pressure drop for laminar and turbulent flow of commercial slurries through pipeline. In the current research fly ash slurry at high concentration is chosen for rheological analysis. The effect of particle size and solid concentration is experimentally tested over the rheological behavior of slurry and based on the rheological data a correlation is developed for calculation of pressure drop in slurry pipeline. Findings The present study strongly supports the analytical approach of pressure drop prediction based on the rheological parameters obtained from the bench scale tests. The rheological properties are strongly influenced by particle size distribution (PSD), shear rate and solid mass concentration of the slurry samples. Pressure drop along the pipeline is highly influenced by flow velocity and solid concentration. The presence of coarser particles in the slurry samples also leads to high pressure drop along the pipeline. As the concentration of solid increase the shear stress and shear viscosity increase cause higher pressure drop. Research limitations/implications The transportation of slurry in the pipeline is very complex as there are lot of factors that affect the flow behavior of slurry in pipelines. From the vast study of literature it is found that flow behavior of slurry changes with the change in parameters such as solids concentration, flow velocity, PSD, chemical additives and so on. Therefore, the accurate prediction of hydraulic parameter is very difficult. Different slurry samples behave differently depending upon their physical and rheological characteristics. So it is required to study each slurry samples individually that is time-consuming and costly. Practical implications Nowadays in the world, long distance slurry pipelines are used for the transportation of highly concentration slurries. Many researchers have carried out an experiment in the design aspects of hydraulic transportation system. Rheological characteristics of slurry also play crucial role in determining important parameters of hydraulic conveying such as head loss in commercial slurry pipeline. The current research is useful for the prediction of pressure drop based on rheological behavior of fly ash slurry at various solid concentrations. The current research is helpful for finding the effect of solid concentration and flow velocity on the flow behavior of slurry. Social implications Slurry pipeline transportation has advantages over rail and road transportation because of low energy consumption, economical, less maintenance and eco-friendly nature. Presently majority of the thermal power plants in India and other parts of the world dispose of coal ash at low concentration (20 per cent by weight) to ash ponds using the slurry pipeline. Transporting solids in slurry pipelines at higher concentrations will require a thorough knowledge of pressure drop. In the current research a rheological model is proposed for prediction of pressure drop in the slurry pipeline, which is useful for optimization of flow parameters. Originality/value All the experimental work is done on fly ash slurry samples collect from the Jharli thermal power plant from Haryana State of India. Bench scale tests are performed in the water resource laboratory of IIT Delhi for physical and rheological analysis of slurry. It has been shown in the results that up to solid concentration of 50 per cent by mass all the samples behave as non-Newtonian and follows a Herschel–Bulkley model with shear thickening behavior. In the present research all the result outcomes are unique and original and does not copied from anywhere.

Oxygen transfer parameters and oxygen uptake rates revisited

This paper provides a review of the essential equations and parameters that are used to design bioreactor aeration systems. Major objectives were to determine if the log-deficit method (LDM) and non-linear regression method (NLRM) yielded different results for the volumetric oxygen mass transfer coefficient (KL a)T and dissolved oxygen (DO) saturation concentration (Cs)T . Another objective was to compare and evaluate oxygen uptake rates (OURs) from the traditional BOD bottle technique with OURs determined from mass balances around completely-mixed activated sludge (CMAS) reactors. Full- and bench-scale, non-steady state reaeration tests were performed using sodium sulfite and cobalt chloride in addition to operating bench-scale CMAS reactors. Full-and bench-scale reaeration testing indicated there was no significant difference in the estimate of (KL a)T in tap water using the LDM or NLRM. Similarly, (Cs)T values were the same for the LDM and NLRM for 70 out of 119 reaeration tests. Actual oxygen uptake rates (AOURs) measured using the BOD bottle technique versus calculated oxygen uptake rates (COURS) were the same for 26 out of 51 data sets evaluated. The alpha-factor (α) increased as the solids retention time (SRT) was increased.

Experimental study on influencing factors of NOx reduction by combining air staging and reagent injection

ABSTRACT This work indicates the functionality of injection reagent combined with air staging, which achieves a better NOx reduction than bare air staging in coal combustion. The key influencing factors of NOx reduction were investigated by experiments on a bench-scale combustion test system. The results showed that the NOx reduction efficiency could be increased by 22.2% compared to bare air staging. The primary stoichiometric ratio SR1 was the key parameter, and the optimum SR1 for NOx reduction by injection was 0.85. There was no benefit for NOx reduction by injection urea in the very fuel-rich zone, but when SR≥1, the injected urea solution at the higher temperature leads to more NOx formation. A higher temperature greatly improved NOx reduction by injection when SR1 was less than 1. It is because that high temperatures were the necessary condition for a greater generation of OH free-radicals, which promoted NOx reduction with NH3 in the absence of oxygen. Therefore, this technology broken through the limitation of narrow temperature window in the traditional technologies with NO reduction by NH3 reagent. Moreover, deeper NOx reduction can be achieved by this technology combined with the existing low NOx combustion technologies.

2D DEM analysis of the interactions between bio-inspired geo-probe and soil during inflation–deflation cycles

The cone penetration test and the standard penetration test are perhaps the most versatile techniques for investigating soil properties in-situ. Advancing the probe through the soil requires substantial downforce due to friction between the probe and the soil. Inspired by the ability of worms to conform their body to the most mechanically advantageous shape while tunneling, an innovative self-excavating geo-probe has been developed and deployed in a laboratory environment. Analogous to a worm’s ability to expand its body, a soft balloon mounted behind a rigid cone is inflated or deflated by applying pressure or vacuum periodically to alter the cone penetration resistance. Laboratory experiments have shown promising results that the new geo-probe can penetrate the soil more efficiently. However, the interactions at balloon–soil–cone interfaces are complex and not fully understood. This numerical study focuses on the behavior of the geo-probe during balloon inflation and deflation. A two-dimensional discrete element model is developed to provide particle-level insight into the micromechanics of the interactions between the geo-probe and the soil. A baseline simulation is first conducted to study the failure mechanisms of the bulk soil during inflation and deflation. Additionally, the contact forces at balloon–soil and soil–cone interfaces are analyzed to show the variation of penetration resistance. The displacement field, shear strain field, and contact force chains are numerically investigated to gain a fundamental understanding of the tool–soil interaction. Then, the effect of balloon locations and overburden stresses on the behavior of the probe are studied by performing sensitivity analyses. This study provides a numerical technique to study the tool–soil interactions that was inaccessible in laboratory test. Implementation of the simulation results enables extrapolation of bench-scale testing to a wider range of stresses and boundary conditions.

Development and Validation of Technologies for Remediation of 1,2,3-Trichloropropane in Groundwater

1,2,3-Trichloropropane (TCP) is a synthetic chemical with known and suspected human health effects associated with exposure. In response to the identification of TCP in environmental media, several states in the United States (US) have set maximum contaminant levels (MCLs) for TCP in drinking water and guidance values for TCP in groundwater. Current treatment methods for TCP in groundwater are limited and can be cost prohibitive. The purpose of this review is to summarize the state of knowledge on TCP remedial technologies and describe efforts to develop and validate promising treatment methods. In situ chemical reduction (ISCR) and in situ bioremediation (ISB) have shown the most potential for TCP remediation. ISCR of TCP by zero-valent zinc (ZVZ) has been evaluated for several years through bench-scale testing, field-scale column testing, and a pilot-scale ZVZ injection program. Additional injections are ongoing to assess the long-term efficacy of ISCR. ISB under anaerobic conditions has been evaluated in laboratory studies and at the field scale with bioaugmentation. Field-scale evaluation of ISB is also ongoing. This review provides an overview of TCP, including use, physicochemical properties, fate and transport, health effects, and current regulation. The states of treatment technologies for TCP are detailed, including granular activated carbon (GAC), ISCR, ISB, and chemical oxidation. Case studies and notable findings are described for ISCR and ISB. While knowledge gaps remain for ISCR and ISB, results to date for these technologies are encouraging.