Pilot-scale Setup Research Articles

Optimization of an rGO-based biosensor for the sensitive detection of bovine serum albumin: Effect of electric field on detection capability

Despite significant progress in the field of biosensing, the impact of electric field on biosensor detection capability and the feasibility of the biosensor application in wastewater has yet to be investigated. The objective of this study was to develop a low-cost, highly sensitive, and selective reduced graphene oxide (rGO)-based biosensor. The constructed biosensor consists of an in-house prepared GO and a four-terminal Kelvin sensing. Spin-coating was chosen as the deposition technique and results revealed an optimal GO number of layers and concentration of 7 and 2mg/mL, respectively. Experiments to determine the effects of electric field on the performance of the biosensor showed significant changes in the biosensor surface, also presenting a direct impact on the biosensor functionality, such that the biosensor showed an increase in limit of detection (LOD) from 1 to 106fg/mL when the applied voltage was increased from 0.0008 to 0.2V. Furthermore, this study successfully explores a pilot scale setup, mimicking wastewater flow through sewage pipelines. The demonstrated improvements in the detection capability and sensitivity of this biosensor at optimized testing conditions make it a promising candidate for further development and deployment for the detection of protein analytes present at very low concentrations in aqueous solutions. In addition, the application of this biosensor could be extended to the detection of protein analytes of interest (such as the spike protein of SARS-CoV-2) in much more complex solutions, like wastewater.

A Combined Field–Lab Approach for Assessing Salmonella Infantis Persistence in Broiler Litter in a Stockpile and Composting Sleeve

Broiler litter (BL) is often contaminated by a variety of zoonotic pathogens. This study attempts to assess the persistence of Salmonella enterica serovar Infantis (S. Infantis) in BL based on spatial and temporal variation of physicochemical properties in a stockpile and composting sleeve. A single trial of two pilot-scale setups, ~35 m3 each, included an open static pile (stockpile) and composting in a polyethylene sleeve with forced aeration. The initial water content was adjusted only for the sleeve (~50% w/w) as in a common composting practice. Both systems were monitored weekly and then biweekly during 2 months in 47–53 sampling points each on every campaign. Measurements included temperature, water content, pH, electrical conductivity (EC), gas-phase oxygen, and ammonia, and the collected data were used to construct multiple contour grid maps. Of the stockpile volume, 83, 71, and 62% did not reach the commonly required minimum temperature of 55°C for three consecutive days during the first, second, and third weeks, respectively. Oxygen levels showed a strong gradient across the stockpile, while anaerobic conditions prevailed in the core. Variation was also recorded within the sleeve, but due to the water content adjustment and active aeration, the conditions favored more intense degradation and higher temperatures. Combining the grid maps drawn in this study with decay rate constants recently published for S. Infantis in BL under 36 combinations of temperature, water content, and pH, we assessed the spatial persistence of S. Infantis in the stockpile and the sleeve. Temperature was shown as a major factor, while water content and pH had only a small effect, in the stockpile only. Co-correlations between temperature, water content, EC, and oxygen suggest that selected physicochemical properties may be sufficient for such assessments. Up to 3 weeks would be recommended to achieve 7–8 log10 reduction in Salmonella in a stockpile, while this would be fully achieved within 1 week in a sleeve. This approach of combining high-resolution spatial field sampling along with decay rates of pathogens under controlled lab conditions may improve quantitative microbial risk assessments and future regulations of manure utilization.

Removal of sulfur dioxide by carbon impregnated with triethylenediamine, using indigenously developed pilot scale setup.

In order to provide protection against extremely toxic gases, activated carbon (AC) adsorption has long been regarded to be a useful technology in terms of gas removal. AC without chemical impregnation has been considerably less effective than impregnated ACs. AC in present use was modified with an organic amine, i.e., triethylenediamine (TEDA) to enhance the physical and chemical properties of AC in order to remove specific poisonous gases. With the rising concern on environmental pollution, there has been an increased curiosity in ACs as the means for eliminating pollutants from environment. Purpose of this study was to assess the TEDA impregnated AC in terms of adsorption capability for simulant gas like SO2. Analysis was done in a properly designed setup. By using the scheme reported here, significant adsorption of toxic gas was obtained. Maximum removal capability observed by AC-4 for SO2 gas was 374 mg/g-C and its breakthrough time was 264 min. Breakthrough time and adsorption capacity of AC-4 was found to be 25 times and 10 times greater as compared to raw AC. Different characterization techniques were also used to study impregnated AC. It was found that chemical adsorption was the crucial means by which TEDA-impregnated AC removed the simulant gas. Langmuir model was best to represent equilibrium, and adsorption kinetics follow second-order model. The process was endothermic, favorable, and spontaneous.

Transaminase Engineering and Process Development for a Whole-Cell Neat Organic Process to Produce (R)-α-Phenylethylamine

The production of (R)-α-phenylethylamine ((R)-α-PEA) from acetophenone is a classic reaction for the characterization of transaminases. However, developing a commercially viable transaminase process to manufacture (R)-α-PEA usually suffers from two drawbacks. One is related to the biocatalyst itself, since transaminases are easily inhibited by (R)-α-PEA at low concentrations. The other drawback is a common low space-time yield of typical transaminase processes, because the reaction equilibrium greatly favors the formation of acetophenone over (R)-α-PEA. In this study, an (R)-selective amine transaminase (TA) from Aspergillus fumigatus Af293 was engineered by a directed evolution for an efficient process to produce (R)-α-PEA. The evolved variant showed an over 3000-fold increase in activity and a tolerance with 2.0 M isopropylamine as well as the complete absence of inhibition by (R)-α-PEA. At the same time, using this evolved TA variant, a continuous neat organic process using whole-cells was developed where the biocatalyst and remaining acetophenone can be efficiently separated from (R)-α-PEA and reused repetitively. This not only decreases the overall cost and waste generation but also achieves a very high space-time yield of up to 168 g L–1 d–1 of (R)-α-PEA in an industrial pilot scale setup.

Statistical optimization of extraction column parameters for the zinc (ll) solvent extraction by D2EHPA in a continuous mode

The efficiency of zinc(II) extraction with di(2-ethylhexyl) phosphoric acid (D2EHPA) diluted in kerosene has been investigated in batch and continuous extraction columns, enabling a comparison between the performance of spray and packed column. The effect of pH of the aqueous phase, reaction time, and extractant volume ratio were considered as the operational variables in a lab-scale mixer-settler in batch mode. The optimum values for each variable were determined and used as the constant values in the pilot-scale continuous setup for optimization of the extraction process in the columns. A pilot-scale setup can provide more relatable results to industrial-scale production. The effect of dispersed phase flow rate, system temperature, nozzle diameter, and height of packing were investigated in continuous mode in spray and packed pilot-scale columns. To minimize the number of experiments, the response surface methodology (RSM) design of experiments (DOE) was adopted using five levels for each parameter. The effect of each variable and their binary and ternary interactions were analyzed by analysis of variance (ANOVA) with a confidence level of 95%. Maximum zinc extraction efficiency in the batch mode was 93.63%, which occurred at the pH of 2, a reaction time of 25 min, and an extractant volume ratio of 15% (V/V D2EHPA to kerosene). Maximum zinc extraction in the spray and packed columns were 76.13% and 84.06%, respectively. Despite the lower extraction efficiency in the continuous mode, a considerably lower required organic to aqueous ratio make these setups more favorable over traditional mixers.

Pilot-scale valorization of hazardous aluminum dross into γ-Al2O3 nanoadsorbent for efficient removal of fluoride

In this study, secondary aluminum dross as an alumina-rich resource was valorized into the gamma-aluminum oxide ( γ -Al 2 O 3 ) via a pilot-scale extraction system. The pilot-scale process was designed for a total γ -Al 2 O 3 production of ∼ 5 kg/day. The extraction process included leaching, precipitation, hydroxide separation, aluminum hydroxide re-precipitation, drying and high-temperature dihydroxylation The obtained γ -Al 2 O 3 was then characterized using XRD, XRF, BET, and FESEM. The XRD analysis disclosed the emergence of the gamma-crystalline phase with a crystallite size of 19.6 nm. The XRF revealed a purity of more than 99 wt%. The BET surface area, pore volume, and mean pore size were ∼ 170 m 2 /g, 0.45 cm 3 /g, and 17.4 nm, respectively. The FESEM and TEM indicated that the as-synthesized γ -Al 2 O 3 was in the form of agglomerates, consisting of <20 nm particles. The γ -Al 2 O 3 was then used to adsorb aqueous fluoride with two different concentrations of 10 and 20 ppm. The adsorption results revealed that the amount of fluoride adsorbed by γ -Al 2 O 3 was 16.5 mg/g when adsorbent dosage, initial fluoride concentration, pH, and equilibrium time were 1 g/l, 20 ppm, 4, and 1 h, respectively. The maximum monolayer adsorption was obtained 35.6 mg/g by Langmuir model. Investigating the influence of the adsorbent dosage indicated that the adsorbent dosage of 4 g/l resulted in 98% fluoride removal. It was found that fluoride adsorption occurred through chemisorption, and carbonate and phosphate anions had the most interference with fluoride adsorption. The regeneration experiments showed that the regenerated γ -Al 2 O 3 can exhibit good fluoride adsorption performance, even after 8 times regeneration. • Aluminum dross was valorized into high purity γ -Al 2 O 3 by a pilot-scale setup. • γ -Al 2 O 3 capacity production of extraction setup was about 5 kg/day. • The obtained γ -Al 2 O 3 could remove 98% of fluoride from aqueous solution after 1 h. • The maximum monolayer adsorption was obtained 35.6 mg/g by Langmuir model. • γ -Al 2 O 3 exhibits 75% of its initial adsorption capacity after 8 times regeneration.

A Novel Metagenomic Workflow for Biomonitoring across the Tree of Life using PCR-free Ultra-deep Sequencing of Extracellular eDNA

Biodiversity is declining on a planetary scale at an alarming rate due to anthropogenic factors. Classical biodiversity monitoring approaches are time-consuming, resource-intensive, and not scalable to address the current biodiversity crisis. The environmental DNA-based next-generation biomonitoring framework provides an efficient, scalable, and holistic solution for evaluating changes in various ecological entities. However, its scope is currently limited to monitoring targeted groups of organisms using metabarcoding, which suffers from various PCR-induced biases. To utilise the full potential of next-generation biomonitoring, we intended to develop PCR-free genomic technologies that can deliver unbiased biodiversity data across the tree of life in a single assay. Here, we present a novel metagenomic workflow comprising of a lysis-free extracellular DNA enrichment protocol from large-volume filtered water samples, a completely PCR-free library preparation step, an ultra-deep next-generation sequencing, and a pseudo-taxonomic assignment strategy using the dual lowest common ancestor algorithm. We demonstrate the utility of our approach in a pilot-scale spatially-replicated experimental setup in Chilika, a large hyper-diverse brackish lagoon ecosystem in India. Using incidence-based statistics, we show that biodiversity across the tree of life, from microorganisms to the relatively low-abundant macroorganisms such as Arthropods and Fishes, can be effectively detected with about one billion paired-end reads using our reproducible workflow. With decreasing costs of sequencing and the increasing availability of genomic resources from the earth biogenome project, our approach can be tested in different ecosystems and adapted for large-scale rapid assessment of biodiversity across the tree of life. *1

Mitigation of Gaseous Emissions from Stored Swine Manure with Biochar: Effect of Dose and Reapplication on a Pilot-Scale

Rural communities are affected by gaseous emissions from intensive livestock production. Practical mitigation technologies are needed to minimize emissions from stored manure and improve air quality inside barns. In our previous research, the one-time surficial application of biochar to swine manure significantly reduced emissions of NH3 and phenol. We observed that the mitigation effect decreased with time during the 30-day trials. In this research, we hypothesized that bi-weekly reapplication of biochar could improve the mitigation effect on a wider range of odorous compounds using a larger scale and longer trials. The objective was to evaluate the effectiveness of biochar dose and reapplication on mitigation of targeted gases (NH3, odorous, volatile organic compounds VOCs, odor, greenhouse gases (GHG)) from stored swine manure on a pilot-scale setup over 8-weeks. The bi-weekly reapplication of the lower biochar dose (2 kg/m2) showed much higher significant percentage reductions in emissions for NH3 (33% without and 53% with reapplication) and skatole (42% without and 80% with reapplication), respectively. In addition, the reapplication resulted in the emergence of a statistical significance to the mitigation effect for all other targeted VOCs. Specifically, for indole, the percentage reduction improved from 38% (p = 0.47, without reapplication) to 78% (p = 0.018, with reapplication). For phenol, the percentage reduction improved from 28% (p = 0.71, without reapplication) to 89% (p = 0.005, with reapplication). For p-cresol, the percentage reduction improved from 31% (p = 0.86, without reapplication) to 74% (p = 0.028, with reapplication). For 4-ethyl phenol, the percentage emissions reduction improved from 66% (p = 0.44, without reapplication) to 87% (p = 0.007, with reapplication). The one-time 2 kg/m2 and 4 kg/m2 treatments showed similar effectiveness in mitigating all targeted gases, and no statistical difference was found between the dosages. The one-time treatments showed significant percentage reductions of 33% and 42% and 25% and 48% for NH3 and skatole, respectively. The practical significance is that the higher (one-time) biochar dose may not necessarily result in improved performance over the 8-week manure storage, but the bi-weekly reapplication showed significant improvement in mitigating NH3 and odorous VOCs. The lower dosages and the frequency of reapplication on the larger-scale should be explored to optimize biochar treatment and bring it closer to on-farm trials.

Mitigation of Odor, NH3, H2S, GHG, and VOC Emissions With Current Products for Use in Deep-Pit Swine Manure Storage Structures

Odorous gas emissions from swine production have been a concern for neighbors and communities near livestock farms. Manure storage is one of the main sources of gaseous emissions. Manure additive products are marketed as a simple solution to this environmental challenge. Manure additives are user-friendly for producers and can be applied (e.g., periodically poured into manure) without changing the current manure storage structure. Little scientific data exist on how these products perform in mitigating gaseous emissions from swine manure. The research objective was to evaluate the effectiveness of 12 marketed manure additives on mitigating odor, ammonia (NH3), hydrogen sulfide (H2S), greenhouse gases (GHG), and odorous volatile organic compounds (VOCs) from stored swine manure. A controlled pilot-scale setup was used to conduct 8-week long trials using manufacturer-prescribed dosages of additives into swine manures. Manure was outsourced from three swine farms to represent a variety of manure storage types and other factors affecting the properties. Measured gaseous emissions were compared between the treated and untreated manure. None of the tested products showed a significant reduction in gaseous emissions when all (n = 3) manures were treated as replicates. Selected products showed a wide range of statistically-significant reduction and generation of gaseous emissions when emissions were compared in pairs of manure types from one farm. The latter observation highlighted the lack of consistent mitigation of gaseous emissions by manure additives. The results of this study do not warrant full-scale trials with the tested products.

Separation of Fructose and Glucose via Nanofiltration in Presence of Fructooligosaccharides.

Fructose and glucose are commonly present together in mixtures and may need to be separated. Current separation methods for these isomers are complex and costly. Nanofiltration is a cost-effective method that has been widely used for separating carbohydrates of different sizes; however, it is not commonly used for such similar molecules. Here, we report the separation of fructose and glucose in a nanofiltration system in the presence of fructooligosaccharides (FOS). Experiments were performed using a pilot-scale filtration setup using a spiral wound nanofiltration membrane with molecular weight cutoff of 1 kDa. We observed three important factors that affected the separation: (1) separation of monosaccharides only occurred in the presence of FOS and became more effective when FOS dominated the solution; (2) better separation was achieved when the monosaccharides were mainly fructose; and (3) the presence of salt improved the separation only moderately. The rejection ratio (Rf/Rg) in a fructose/glucose mixture is 0.92. We reported a rejection ratio of 0.69, which was observed in a mixture of 50 g/L FOS with a fructose to glucose ratio of 4.43. The separation is hypothesized to occur due to selective transport in the FOS layer, resulting in a preferential binding towards fructose.

Dynamically Operated Fischer–Tropsch Synthesis in PtL—Part 2: Coping with Real PV Profiles

Climate change calls for a paradigm shift in the primary energy generation that comes with new challenges to store and transport energy. A decentralization of energy conversion can only be implemented with novel methods in process engineering. In the second part of our work, we took a deeper look into the load flexibility of microstructured Fischer–Tropsch synthesis reactors to elucidate possible limits of dynamic operation. Real data from a 10 kW photovoltaic system is used to calculate a dynamic H2 feed flow, assuming that electrolysis is capable to react on power changes accordingly. The required CO flow for synthesis could either originate from a constantly operated biomass gasification or from a direct air capture that produces CO2; the latter is assumed to be dynamically converted into synthesis gas with additional hydrogen. Thus two cases exist, the input is constantly changing in syngas ratio or flow rate. These input data were used to perform challenging experiments with the pilot scale setup. Both cases were compared. While it appeared that a fluctuating flow rate is tolerable for constant product composition, a coupled temperature-conversion relationship model was developed. It allows keeping the conversion and product distribution constant despite highly dynamic feed flow conditions.

Moving from lab to pilot scale in forward osmosis for pesticides rejection using aquaporin membranes

Abstract Often FO experiments are carried out with the prevalent FO lab-scale setup using a moderate-sized flat sheet membrane. This necessitates spending funds on providing FO apparatuses and using higher area of FO membranes associated with a larger amount of chemicals to evaluate the performance of the FO process in rejection of compounds of interest. In this paper, we used two different FO setups, a typical lab-scale system using flat sheet aquaporin membrane as well as a small pilot-scale setup using hollow fiber aquaporin membrane, to remove three pesticides from water: 2–6 Dichloro-benzamide (BAM), 2-methyl-4-chlorophenoxyaceticacid (MCPA), and 2-(4-Chloro-2-methylphenoxy)propionic acid (MCPP). The obtained rejection data of BAM was compared to our previous study on aquaporin FO membrane using a tiny FO system to investigate the effect of going from a tiny lab-scale to a pilot-scale setup. The diffusion-controlled rejection of BAM was found to be 93–94% using the standard lab-scale flat sheet membrane system while that was 98.7% using the pilot-scale hollow fiber membrane which is in accordance to our preliminary result of >97% with the tiny system. This study confirms the hypothesis that we can employ a very small piece of membrane and accurately use it to estimate the rejection performance of a pilot-scale FO membrane system. This finding allows for a cost-effective and quick test of a large number of molecules by most importantly, the use of a tiny piece of FO membrane. Moreover, both systems, in particular, the hollow fiber setup demonstrated an excellent rejection capability for the charged phenoxy acid herbicides by having rejection values of 99.2% for both MCPA and MCPP.

Cyanobacterial Growth in Minimally Amended Anaerobic Digestion Effluent and Flue-Gas.

Anaerobic digestion (AD) is an important industrial process, particularly in a biorefinery approach. The liquid effluent and carbon dioxide in the off-gas, can be used to produce high-value products through the cultivation of cyanobacteria. Growth on AD effluent is often limited due to substrate limitation or inhibitory compounds. This study demonstrates the successful cultivation of Synechococcus on minimally amended AD effluent, supplemented with MgSO4 and diluted with seawater. An 8 L airlift reactor illustrated growth in a pilot scale setup. Higher biomass yields were observed for cyanobacteria grown in diluted AD effluent compared to minimal medium, with 60% total nitrogen removal in the effluent. It was demonstrated that controlling the pH, increasing dissolved salt concentrations and adding MgSO4 to the effluent allowed for the successful cultivation of the cyanobacterium, circumventing the addition of clean water for effluent dilution. This could ultimately increase the feasibility of anaerobic digestion-microalgae integrated biorefineries.

Nanofiltration separation of succinic acid from post-fermentation broth: Impact of process conditions and fouling analysis

Abstract In this study a pilot-scale setup was used in the nanofiltration (NF) process for recovery of succinic acid from model solutions and the actual post-fermentation broth left after the bioconversion of glycerol. The effects of composition and pH of feed solutions, initial concentration of components and the magnitude of applied transmembrane pressure (TMP) on the separation efficiency, the value of the permeate flux and retention ratio of individual components present in the feed solutions, were investigated. In order to estimate the mechanism of membrane layer fouling formation, the experimental data obtained were compared to the Hermia model.

Electrospinning of Block and Graft Type Silicone Modified Polyurethane Nanofibers.

Silicone modified polyurethane (PUSX) has attracted interest as a useful material by various properties, which are combined with silicone and polyurethane. In this paper, we tried to optimize the electrospinning process of silicone modified polyurethane (PUSX) nanofibers on a lab scale device and a multinozzle pilot scale set-up to investigate the potential and limitations of preparing PUSX nanofibrous sheets using different equipment. The morphology and diameter of the obtained fibers were studied via scanning electron microscopy (SEM). Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) was also carried out to analyze the chemical structure of PUSX nanofibers. As a result, we successfully figured out the optimal parameters of PUSX electrospinning process and demonstrated the great potential of the process for mass production of PUSX nanofibrous sheets from solutions.

Module scale-up and performance evaluation of thin film composite hollow fiber membranes for pressure retarded osmosis

Abstract Pressure retarded osmosis (PRO) demonstrates great potential in energy harvesting when combining with seawater reverse osmosis. However, the lack of suitable membrane modules and the issue caused by the membrane fouling greatly impede the practical application of PRO to a larger scale. In this study, two-inch thin film composite hollow fiber modules were fabricated by using in-house developed PRO membranes. The produced PRO modules have a maximum effective area of 0.5 m2. By assessing the PRO performances of the modules with different sizes, external concentration polarization (ECP) was found to have significant impact on the flux reduction during module scale-up. Different module designs, including fiber bundles, distribution baffles and distribution tubes, were thus adopted as an attempt to boost the membrane performance. A power density of 8.9 W/m2 at 15 bar was obtained using tap water as feed and 1 M NaCl solution as draw solution. PRO performance tests were also carried out using the developed two-inch modules on a pilot-scale setup with actual wastewater retentate as feed solution. Low pressure nanofiltration was selected as the pretreatment of the wastewater retentate to mitigate fouling. A power density of larger than 8 W/m2 was obtained when pretreated wastewater retentate was used as the feed solution, implying high potential of PRO in the pilot scale. Nevertheless, full potential of PRO can only be realized by mitigating ECP, which could be achieved by improving the module design in the further endeavor.

Pilot-Scale Experimental Study on Phase Diagrams of Pressurized Pneumatic Conveying with Pulverized Coal

Pressurized pneumatic conveying plays an important role in large-scale coal gasification systems. Some of the underlying mechanisms affecting the conveying characteristics remain open issues. Phase diagrams can provide key information regarding flow characteristics by revealing the relationship between pressure drop and superficial gas velocity, which can be utilized for flow pattern identification, stability analysis, and system optimization, in an economic and feasible way. The present work experimentally investigated phase diagrams of pressurized pneumatic conveying on a pilot-scale setup, with three types of the most widely used pulverized coal in China selected as the conveyed materials. The effects of superficial gas velocity, solid-phase mass flow rate, pipeline layout, particle size, coal type, and moisture content were studied, respectively. The findings will contribute to a better understanding of the underlying mechanism of pressurized pneumatic conveying with pulverized coal, and to a better g...

THICKENING OF ALUM SLUDGE USIN FLOATABLE MEDIA FILTER

A pilot scale filter was tested for thickening of alum sludge generated during the production of potable water in a conventional compact water treatment plant (WTP). The alum sludge is produced from coagulation / flocculation / sedimentation processes that are using aluminum sulfate (Alum) (Al2 (SO4)3. 18H2O). The pilot scale was fabricated from scheduled uPVC pipe. The reactor was filled with floatable media (polystyrene) working as filtration media with counter flow concept. The alum sludge was discharged in the pilot scale setup from the sludge holding tank in the WTP using submersible pump. The pilot scale filter was tested at different rate of filtration (ROF) ranged from 25 to 400 m3/m2/d. In addition, different media heights (100 – 800 mm) were investigated to study the efficiency of the sludge thickening. The filter washing rate (ROW) was tested to determine the optimum ROW that will clean the filter. ROW equal to one to four times the ROF were investigated. The efficiency of the sludge thickening was achieved around 30% at the optimum range of ROF that founded in the range of 150 - 200 m3/m2/d and the filtration media height between 400-600 mm. at the optimum operating conditions, the floatable media filter had the ability to thicken the alum sludge and, the turbidity of the water produced after thickening were less than 12 NTU.

Real-time detection of organic contamination events in water distribution systems by principal components analysis of ultraviolet spectral data.

The detection of organic contaminants in water distribution systems is essential to protect public health from potential harmful compounds resulting from accidental spills or intentional releases. Existing methods for detecting organic contaminants are based on quantitative analyses such as chemical testing and gas/liquid chromatography, which are time- and reagent-consuming and involve costly maintenance. This study proposes a novel procedure based on discrete wavelet transform and principal component analysis for detecting organic contamination events from ultraviolet spectral data. Firstly, the spectrum of each observation is transformed using discrete wavelet with a coiflet mother wavelet to capture the abrupt change along the wavelength. Principal component analysis is then employed to approximate the spectra based on capture and fusion features. The significant value of Hotelling's T2 statistics is calculated and used to detect outliers. An alarm of contamination event is triggered by sequential Bayesian analysis when the outliers appear continuously in several observations. The effectiveness of the proposed procedure is tested on-line using a pilot-scale setup and experimental data.

Modeling Soluble and Particulate Lead Release into Drinking Water from Full and Partially Replaced Lead Service Lines.

Partial replacement of lead service lines (LSLs) often results in the excessive long-term release of lead particulates due to the disturbance of pipe scale and galvanic corrosion. In this study, a modeling approach to simulate the release and transport of particulate and dissolved lead from full and partially replaced LSLs is developed. A mass-transfer model is coupled with a stochastic residential water demand generator to investigate the effect of normal household usage flow patterns on lead exposure. The model is calibrated by comparing simulation results against experimental measurements from pilot-scale setups where lead release under different flow rates and water chemistry scenarios was reported. Applying the model within a Monte Carlo simulation framework, partial replacement of the LSL was predicted to result in releasing spikes with significantly high concentrations of particulate lead (1011.9 ± 290.3 μg/L) that were five times higher than those released from the simulated full LSL. Sensitivity analysis revealed that the intensity of flow demands significantly affects particulate lead release, while dissolved lead levels are more dependent on the lengths of the stagnation periods. Preflushing of the LSL prior to regulatory sampling was found to underestimate the maximum monthly exposure to dissolved lead by 19%, while sampling at low flow rates (<5.2 LPM) was found to consistently suppress the high spikes induced by particulate lead mobilization.