Evaluation Of First Flush Phenomena For Chemical And Microbiological Pollutants In Red Cedar River
Authors: Amira Oun; Ao Chen; Fangli Xing; Thomas Voice; David Long; Irene Xagoraraki
Abstract: Michigan climate is characterized by hot humid summer, cold and snow winter, and wet spring. The state receives a good amount of perception throughout the year, averaging from 30-40 inches annually. Typically, from November through March is slightly drier, while April through August is wetter than the rest of the year. This climate creates a long period for pollutant build-up which is deposited on surfaces during dry weather then washed away in spring when the snow start to melt into rivers, storm drains and lakes. The initial storms of the spring season usually have higher pollutant concentrations, which create a first flush phenomenon. These pollutants can be from different sources such as De-icing salt, animal waste, manure and biosolid, pesticides and fertilizers.in this study water samples were collected from Red Cedar River, a stream flowing through farmland and receiving effluent from several municipalities in central Michigan in order to 1)monitor the water quality of the first flush which can give an indication of pollution sources and pollution loads going into the lake Michigan 2) study the fate and transport of these contaminants (chemical and microbiological) 3)and study the effect of the DOC in nutrients and contaminants release and transport. We analyzed extensive data sets, collected over spring and summer 2013 and will continue sampling in spring and summer of 2014. The samples were analyzed for fecal indicators (E.coli), human and bovine associated Bacteroides markers, DOC, sodium, potassium, chloride and nitrate.
Abundance Of Segmented Filamentous Bacteria In Mice With And Without 2,3,7,8-tetrachlorodibenzo-p-dioxin Treatment
Authors: Prianca Bhaduri; Timothy R. Zacharewski; Norbert E. Kaminski; James M. Tiedje; Syed A. Hashsham
Abstract: Gut microbiota influence several key processes in the host including development and maturation of cellular and humoral immune responses, inflammation and pathogen clearance. Segmented filamentous bacteria (SFB) play a unique role in this dynamic system by regulating several immune cells. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) also acts on the immune system through the aryl hydrocarbon receptor to increase the ratio of Treg cells to Th17 cells. In this study, we hypothesized that the abundance of SFBs would increase in response to TCDD dosage in mice. Loop-mediated isothermal amplification (LAMP) primers were designed for 16S rRNA SFB gene and flagellin gene and used to measure SFBs from fecal pellets. Sanger sequencing and comparison to published qPCR primers confirmed the authenticity of the LAMP primers. The presence of SFBs was also confirmed by microscopy. We have also been able to quantify SFBs directly from fecal cell suspensions without the need for DNA extraction. Our results indicate that high amounts of SFBs are present in mice fecal samples even though 454 sequencing using 16S rRNA primers for the V6 region did not detect SFBs in most samples. The abundance of SFBs showed slight increase in the treated animals. These results further our understanding of the intestinal microbial response to TCDD levels in our system. This work increases our knowledge of the role played by the intestinal microbiota in regulating the immune system balance and has implications in several diseases including inflammatory bowel disease, Crohn's disease and others.
This work was supported in part by National Institute of Environmental Health Sciences Superfund Research Program (NIEHS-SRP)
Groundwater Sustainability In Michigan Lowlands – A Multiscale Modeling Study
Authors: Zachary Curtis; Huasheng Liao; Shu-Guang Li
Abstract: Analysis of a statewide groundwater quality database (1,000,000+ samples) reveals that salinity in Michigan’s lowland areas is statistically significantly higher than that in the inland areas at higher elevations. Mounting evidence suggests that brine upwelling is from deep geological formations and that dynamic processes on multiple spatial scales control the extent of pollution in lowland areas. This research investigates how the complex interplay of human activity (increased water withdrawals), climate change (systematic decrease in Great Lakes water levels in the past 30 years) and natural upwelling interact to control the sustainability of freshwater resources in Michigan.
A calibrated multiscale groundwater model will be used to simulate the brine upwelling dynamics and its impact on water resources sustainability in lowland areas of Michigan. This research will utilize a “hierarchical” approach to simulate the flow system at basin scale, regional scale, local scale and site scale. The hierarchical modeling system will be dynamically coupled through iterative “downscaling” and “upscaling” and will be complimented by extensive statewide data and site-specific sampling.
Current work includes the development of a regional and local scale model in the Ottawa Lowlands. Model conceptualization and “first-cut” calibration using integrated well data will direct the data sampling effort through an iterative approach. A monitoring protocol for static water levels and chloride concentrations is also under development and will be carried out in the following semesters. Insights from the Ottawa Lowlands study will help direct the modeling effort of the basin-scale upwelling dynamics likely causing the lowland’s groundwater contamination.
Detection And Removal Methods Of Cyanuric Acid In Swimming Pool Water
Authors: Xu Fan; Susan J. Masten
Abstract: As a common ingredient of bleaches, disinfectants and herbicides, cyanuric acid (2,4,6-trihydroxy-1,3,5-triazine, CA) is widely used in recreational swimming pool water. Specifically, chlorinated salts of CA are functionally important in water purification by releasing disinfectant chlorine, and stabilizing free chlorine. However, as CA acts as a chlorine reservoir, and prevents residual chlorine destruction by sunlight, it also can accumulate in swimming pools.
If a swimming pool has an excessively high concentration of CA, water will become cloudy. It will not only pose potential threat to human health, but also increase difficulty for subsequent water treatment. In addition, CA is a very stable compound, and resistant toward chemical hydrolysis or oxidation. CA is also the final product formed during TiO2-catalyzed photocatalysis of s-triazine herbicides. Therefore, it is essential to develop cost-effective removal methods.
The high-performance liquid chromatography (HPLC) can be used to detect CA. Preliminary studies have been conducted to determine CA concentrations in several public swimming pools in Lansing area. CA levels ranged from 34.03mg/L to 73.61mg/L, all within in recommended level (10 -100 mg/L).
Ozonation-membrane filtration and adsorption have been tested for their efficacy for CA removal. The results show both ozonation-membrane filtration and adsorption on natural zeolite were ineffective. Fortunately, activated carbon shows immense potential for CA adsorption, only 0.4 g granular activate carbon could achieve 69.4% removal rate from a solution containing 500 mg/L CA. Further study will focus on determining adsorption capacities and adsorption rates of various activated carbon sources (GAC, PAC, commercial fish tank carbon).
Genetic Characterization Of Microorganisms On Highly Touched And Untouched Fomites
Authors: Amanda Herzog; Tiffany Stedtfeld; Charles P. Gerba; Joan B. Rose; Syed A. Hashsham
Abstract: In the indoor environment, an important route of transmission of bacterial and viral disease is through the interaction with fomites. Touched fomites are mostly influenced by the interactions with individuals while untouched fomites are influenced by air movement. Understanding the bacterial communities on the fomites in an indoor environment may affect disease transmission models and quantitative microbial risk assessments. Therefore, the work proposed is to analyze the bacterial communities on highly touched and untouched fomites in a university setting. Samples from touched and untouched fomites were collected from the common lounge, computer room, and cafeteria of six dormitories at the University of Michigan. Non-porous fomites of plastic, metal, and wood (e.g. computer mouse, door knob, and window sill, respectively) with surface areas ranging approximately 10 to 100cm2 were sampled using pre-moistened wipes. DNA was exacted from the samples and analyzed using 454 GSFLX Roche sequencing of the 16S rRNA genes. Results from 69 samples shows that the majority of the sequences found on both touched and untouched fomites were from three core phyla, Proteobacteria, Actinobacteria and Firmicutes, which represented an average of 81.4% and 83.8% of the bacteria community on touched and untouched fomites, respectively. The bacterial communities on touched and untouched fomites were statistically different. The bacterial communities on touched fomites were more diverse and had more fecal related bacteria present compared to untouched fomites. There were no correlations observed between sample date/time, locations, dormitory rooms, fomite materials or fomite types. The knowledge of the bacterial communities on touched and untouched fomites can further assist in the role fomites have on the transmission of infectious disease in the indoor environment.
This work was supported in part by This study was supported by the Center for Advancing Microbial Risk Assessment funded by the U.S. Environmental Protection Agency and Department of Homeland Security grant number R83236201.
A Comparison Of RDX Assimilating Microorganisms Across Soil Communities
Authors: Indumathy Jayamani; Alison Cupples
Abstract: The explosive RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) has contaminated many military sites. This chemical is particularly problematic because it is highly soluble and toxic and has the potential to move off-site. Here we combined stable isotope probing (SIP) and high throughput sequencing to identity the microorganisms able to degrade RDX across a number of soils. The final aim is to create a database of microorganisms linked to in situ RDX degradation, so that removal through natural attenuation can be better predicted. The work consisted of an initial screening of soils for RDX degradation followed by SIP combined with high throughput sequencing. SIP experiments involved the exposure of microcosms to labeled (13C3, 99%; 15N3) or unlabeled RDX (present as the only nitrogen source). Two amendments of RDX were used (20 mg/L each). Following complete RDX degradation, DNA was extracted, ultracentrifuged and then fractioned. The fractions generated were amplified using a set of multiplex indexed primers targeting the V4 region. After amplification, individual reactions were quantitated and a pool of equimolar amounts was made. The pool was run on the Illumina MiSeq platform using a standard MiSeq paired end (2x250 bp) flow cell. The high throughput data were analyzed using Mothur. This involved the construction of contigs, error and chimera removal and sequence alignment for OTU assignment. The high throughput sequencing data generated is currently being analyzed and the sequence abundance for each phylotypes is being calculated. The relative abundance of each phylotype in each fraction is currently being examined to identify the organisms responsible for label uptake, hence RDX assimilation, for each soil. The data generated will be compared between soils and the current literature on known RDX degrading species. To our knowledge, this work represents the first attempt to combine both SIP and high throughput sequencing to simultaneously access RDX degraders.
This work was supported in part by SERDP
Common Difficulties In Learning Material Balances And How Certain Teaching Methods Promote Negative Transfer (As Assessed In An Undergraduate Environmental Engineering Classroom)
Authors: Indumathy Jayamani; Susan J. Masten
Abstract: Material balance, a fundamental ‘big idea’ in the field of environmental engineering, is generally introduced in lower level environmental engineering classes. A working knowledge of this concept is required to understand several other higher level topics in the field. Previous experience has shown that students entering higher level courses in environmental engineering often carry naïve conceptions about material balance and follow pattern recognition without fully understanding the underlying assumptions. In our research, we have assessed student performance on mass balance related questions in an upper level environmental engineering course (senior year) to identify common misconceptions and the possible reasons that promote the creation of these misconceptions and negative transfer. A preliminary analysis of the data identified that students have difficulties in solving for the decay rate constant when the system is at steady state and also in writing material balance equations when given a plug flow reactor system. We also found a common tendency to solve problems by searching for a pattern that the students recall rather than using the information provided to evaluate and solve the problem using first principles. This approach underscores the problem of negative transfer. By identifying these misconceptions and difficulties we hope to develop better learning material to enhance student learning of material balance concepts.
DNA-Extraction Free Loop Mediated Isothermal Amplification (LAMP) Of Dehalococcoides spp. And Dehalobacter spp.
Authors: Yogendra Kanitkar; Robert Stedtfeld; Tiffany Stedtfeld; Rob Steffan; Alison Cupples
Abstract: Typically, real time PCR (qPCR) based on TaqMan probe or DNA binding dyes is used to quantify and monitor the in situ activity of Dehalococcoides and Dehalobacter spp. To date, a wide range of qPCR protocols to quantify 16S rRNA genes as well as reductive dehalogenase genes such as vcrA, tceA and bvcA are available. Although qPCR methods have been successful for monitoring reductive dechlorination, DNA extraction and amplification in an expensive real time thermal cycler require significant resources and reasonable expertise. In this study, we provide proof of concept for a novel protocol involving direct amplification (without DNA extraction) to detect and quantify Dehalococcoides and Dehalobacter spp. in commercial reductive dechlorination cultures as well as groundwater samples.
Loop mediated isothermal amplification (LAMP) primers were designed for Dehalococcoides spp. and Dehalobacter spp. 16S rRNA genes and key functional reductive dehalogenase genes using Primer Explorer V4. The method was applied to commercial reductive dechlorinating cultures (SDC-9 and TCA20) and groundwater samples from contaminated sites. For each primer set, threshold times and sensitivities were determined and compared using the DNA-extraction free LAMP assays on a real time PCR thermal cycler.
Candidate primer sets for several key dechlorinating genes associated with Dehalococcoides spp. were identified. The selection was based on the performance of these primers at low detection levels. Furthermore, preliminary data indicates that DNA-extraction free LAMP was able to detect Dehalococcoides spp. below 10-7 cells/L, the accepted threshold for natural attenuation. Future research will focus on the genes associated with Dehalobacter spp.
This work was supported in part by the Strategic Environmental Research and Development Program (SERDP) of the Department of Defense (Project ID# ER-2309)
Antibiotic Resistance Gene Abundance And Diversity In The Great Lakes Region Using Targeted Functional Gene Sequencing And Gene-Z
Authors: Maggie R. Kronlein; Robert D. Stedtfeld; Yen-Chen Liu; James Tiedje; Syed A. Hashsham
Abstract: Heavy use of antibiotics has resulted in the widespread prevalence of antibiotic resistance (AR) genes in bacteria, which is of great concern to human health. Characterizing the abundance and allelic diversity of these AR genes in aquatic environments is the first step for better understanding of the problem. In this study, AR genes were or are in the process of being analyzed in lake and river samples using two approaches: 1) Functional gene targeted next generation sequencing for 200 AR genes using Wafergen platform, and 2) Isothermal amplification based quantification of selected AR genes in a 64-well microfluidic chips using Gene-Z platform. One liter of water samples were collected from 30 lakes and rivers throughout Michigan. Direct amplification of the AR gene containing samples without DNA extraction was also demonstrated for selected samples. Wafergen analysis revealed significantly higher abundance of multiple AR genes (including: tetA, tetM, sul1, aphA3, mphA, aadA, mefA and vanA) throughout Michigan, particularly in areas of high population density, high density of septic tanks, and near treated wastewater discharge points. Future experiments include the analysis of 20 selected AR genes on the Gene-Z platform (patent pending). This study demonstrates the potential of functional gene-based high throughput sequencing and direct amplification in assessing the problems related to antibiotic resistance.
This work was supported in part by the US EPA Great Lakes Restoration Initiative (GLRI) grant number GL-00E01127-0. Gene-Z was development was supported by the 21st Michigan Economic Development Corporation grant number GR-476 PO 085P3000517.
Environmental DNA monitoring of high-risk invasive species in the Great Lakes area using Gene-Z
Authors: Maggie R. Kronlein; Robert D. Stedtfeld; Erin Dreelin; Jo Latimore; R. Jan Stevenson; Syed A. Hashsham
Abstract: Early detection of aquatic invasive species at low infestations is key to protecting natural ecosystems and local economies. Traditional surveys and identification techniques are time-consuming and expensive. Methods relying on environmental DNA (eDNA) detection have the potential to increase the likelihood of detection particularly at lower abundances with fewer resources and more rapidly. In this study, an eDNA isothermal amplification technique was used in conjunction with microfluidic chips and a hand-held genetic analysis device called Gene-Z (patent pending) to monitor approximately 50 Michigan lakes for six ‘high-risk’ invasive species and a number of surrogates. These included three mussels (zebra, quagga, and golden mussels), one plant (Hydrilla), and other invasives (Cercopagis pengoi, Dikerogammarus villosus, Bythotrephes longimanus, Daphnia cristata, Channa argus, Neogobius melanostomus, Orconectes rusticus and Petromyzon marinus). A rapid sampling technique was developed using 35µm filter funnel to recover and concentrate larger cells (veligers, eggs, juveniles) to enhance the detection limit. Initial data analysis confirmed the presence of zebra mussel DNA in most samples (irrespective of their presence by visual methods), and absence of golden mussel. Quagga mussel DNA was present in some lake samples but not others. The eDNA method was rapid (less than 30 min), simple, and quantitative. Simplification of the sampling technique allowed the use of Gene-Z for DNA/eDNA collected from large volumes of water (up to 70,000 L). This method has potential for large-scale deployment and monitoring using a volunteer network..
This work was supported in part by the United States EPA Great Lakes Restoration Initiative (GLRI) grant number GL-00E01127-0.
Evaluating The Effect Of Brown Bridge Dam Removal In Grand Traverse County, MI: An Integrated Hydrological Analysis
Authors: Zhi Li; Shu-Guang Li
Abstract: Many dams are targeted for removal to restore ecosystems, but without having a clear understanding of the effects it will have on the watershed’s ability to avoid flooding. This is due the complex and varied response of different watersheds to dam removal. As such, a deep analysis of the surrounding watershed is required for sound water resource management when considering dam removal.
This research explores the effect of Brown Bridge Dam removal. The Brown Bridge Dam was the first of three dams to be removed (circa January 2013) and is located on the Boardman River approximately 14 miles upstream of Traverse City, MI. A “before-and-after” systematic approach will be used, including watershed and groundwater modeling and hydraulic routing. We use: watershed modeling to determine an overall watershed response to both extreme climate events and changing climates; groundwater modeling to monitor the groundwater distribution caused by dam removal and hydraulic routing to look for peak flow attenuation due to the dam.
Preliminary results suggest that this dam removal can potentially have adverse impacts downstream for this groundwater-dominated watershed. A hydraulic routing analysis shows that the reservoir had the sufficient capacity to decrease flood peaks and manage risks. The analysis of a typical scale flood reveals that a considerable area would be affected by floods. This indicates that the dam removal affected the water level of the Boardman River and the groundwater level within the Boardman River Watershed, matching observations and suggesting the need for a more detailed investigation.
Metagenomics To Study Phage Diversity And Antibiotic Resistance Genes In Activated Sludge From A Wastewater Treatment Plant
Authors: Mariya Munir; Terence Marsh; Irene Xagoraraki
Abstract: Bacteriophages are the most abundant entities in most environments and are being considered a suitable vehicle for the dissemination of antibiotic resistant genes (ARGs). Sludge samples were collected from East Lansing WWTP in Michigan. A method for phage DNA isolation was optimized using PEG (polyethylene glycol) precipitation and DNase (deoxyribonuclease) treatment. Phage diversity was studied by next generation sequencing (before and after DNase treatment) with Illumina (Miseq). Metagenome data analysis reveals that after DNase treatment activated returned sludge sample (RAS) contained 21,985 sequences totaling 17,227,533 basepairs with an average length of 783 bps and primary sludge (PS) sample contained 2,870 contigs sequences totaling 2,292,422 basepairs with an average length of 798 bps. On a genus level, Burkholderia phage, Coliphage, Enterobacteria phage, and Pseudomonas phage are present in all the samples. Burkholderia cepacia phage, Edwardsiella phage, Mycobacterium phage, Salmonella phage, Vibrio phage and Xanthomonas citri phage were phages detected only in RAS samples. Bacillus phage, Brochothrix phage, Lactobacillus phage, Listeria phage, Phormidium phage, Staphylococcus phage and Sugarcane mosaic virus were found only in PS samples.
Phage DNA was isolated and monitored for ARGs (tetracycline resistant genes (Tet-W and Tet-O) and sulfonamide resistant gene (Sul-I)) using real-time Q-PCR. We have detected ARGs in phage DNA with concentrations ranging from 3.84x102-8.14x103 copies/100mL for Tet-W gene and 5.89x104-7.9x104 copies/100mL for Sul-I gene. In additon, phage metagenome was searched for functional signatures of resistance genes and we observed a high resistance to antibiotics and toxins compound in PS samples compared to RAS sample. Further analysis revealed that most of the antibiotic resistance belongs to methicillin, fluoroquinolones and beta-lactamase group of antibiotics. This work presents the abundance of phages in sludge samples and indicates that there is a substantial shift in the phage community over the course of the activated sludge process, thus suggesting that within the activated sludge the phage populations are dynamic. It also indicates that phage DNA is associated with antibiotic resistant genes in wastewater.
Vinyl Chloride Assimilating Microbes From A Contaminated Site-Derived Culture Identified By Stable Isotope Probing And Illumina Sequencing
Authors: Fernanda Paes; Xikun Liu; Timothy Mattes; Alison Cupples
Abstract: Vinyl chloride (VC) is classified as a known human carcinogen and is a common soil and groundwater contaminant. In this study, time series DNA based stable isotope probing (SIP) and high throughput sequencing were combined to identify the microorganisms assimilating carbon from labeled VC (13C2) in a culture derived from contaminated site groundwater. In addition, the composition of the microbial community was investigated. Microcosms were amended with labeled (13C2) or unlabeled (12C) VC and removal was monitored over 45 days. During this time, DNA was extracted at several times (days 15, 32 and 45). Both the total DNA extract samples and the heavy fractions generated during SIP were subject to Illumina sequencing (V4 region of 16S rRNA gene).
The data generated indicated the microbial community was dominated by six phyla (Proteobacteria, Actinobacteria, Acidobacteria, Bacteroidetes, Firmicutes, and Verrucomicrobia). The most abundant families in these phyla included the Comamonadaceae, Burkholderiales incertae sedis, Nocardioidaceae, Chitinophagaceae, Flavobacteriaceae, Clostridiales incertae sedis XI and Gp4. The analysis of the heavy fractions indicated five phylotypes were more dominant in the labeled fractions compared to the controls, including Nocardioides (Actinobacteria), Brevundimonas (Proteobacteria), Gp6 (Acidobacteria), Tissierella (Firmicutes) and unclassified Clostridiales (Firmicutes). These results indicate both a previously identified VC assimilator (Nocardioides) as well as novel VC assimilators and were responsible for label uptake. Examining VC degradation within mixed communities is important because there is likely a greater diversity of VC assimilators in the environment than is currently represented in pure culture.
This work was supported in part by This work was funded by a collaborative NSF Grant (number 1233154) awarded to T. Mattes and A. Cupples.
Produced Water Treatment Using Hybrid Hydrocyclone-Membrane Technology
Authors: Brian Starr; Andrii Gorobets; Volodymyr Tarabara; Merlin Bruening; André Bénard
Abstract: This research aims to develop crossflow filtration hydrocyclone (CFF-HC) as a hybrid hydrocyclone-membrane technology that separates oil-water mixtures into a water stream that meets standards for discharge into the environment and an oil stream sufficiently dewatered for energy use. The hypothesis of this work is that rotational flow in a CFF-HC will force oil droplets away from a membrane surface and reduce fouling. Initial fouling studies using a CFF-HC test apparatus to separate oil-water emulsions have demonstrated that centripetal forces in the membrane reduced fouling compared with conventional crossflow filtration. Commercialization will require the synergistic benefits to outweigh additional complications associated with a hybrid unit. Ongoing work is focused on maximizing the clean water permeate stream while maintaining the reduction in fouling.
This work was supported in part by EPA, NSF
Influence Of Soil Characteristic, Ph And Calcium Ion On Adsorption Behavior Of Aristolochic Acids
Authors: Chaiyanun Tangtong; Lulu Qiao; David T.Long; Thomas C.Voice
Abstract: Aristolochic acids (AAs) were believed as environment agents induced Balkan Endemic Nephropathy (BEN). The fate and transport of AAs in soil is important property in determination of exposure pathway. This study investigated the soil sorption behavior of AAs through batch sorption experiment. The results showed that adsorption isotherm are fitted well to linear type with correlation coefficient (r2)>0.93. Both organic matter and clay were significant components that control the adsorption. In natural soil pH, AAs were in anion form and showed high sorption capacity (Koc are more than 3) even they were very hydrophilic. This finding indicated that specific mechanism had been involved other than hydrophobic partitioning. pH had high effect to sorption of AAs. The sorption coefficient (Kd) of neutral species in acid condition were much higher than anion species in basic condition. This was due to the higher hydrophobic partitioning of neutral molecules and electrostatic repulsion of anion molecules to the soil. Increasing of calcium ion in solution found to promote the adsorption of AAs to soils that had high cation exchange capacity (CEC) which support the idea of cation bridging mechanism. The model of different adsorption capacity among different soil types may describe the available of AAs in BEN and non-BEN area.
This work was supported in part by MSU Center of Water Sciences (CWS), Royal Thai Government, NIH.
Effect Of Ozone Dosage And Hydrodynamic Conditions On Permeate Flux In Titanium Oxide And Manganese Oxide Coated Catalytic Membrane Filtration System
Authors: Xiaoyu Wang; Susan Masten; Simon Davies
Abstract: This project focuses on the effects of ozone dosage and hydrodynamic conditions on the performance of virgin titanium oxide and manganese oxide coated catalytic membrane systems. The coated catalytic membranes are produced by coating commercial ceramic ultrafiltration titanium oxide membranes with manganese oxide nanoparticles using a layer-by-layer self-assembly technique. Membrane fouling (a parameter that significantly affects the design and operation of membrane filtration facilities) was evaluated under different ozone dosages with two operation modes (dead-end and cross-flow). An economic analysis of each membrane system was performed to optimize the design. A comparison of the performance of the two catalytic membrane systems in terms of the recovery of the permeate flux and removal of natural organic matter was also assessed. The results of the proposed projects can be applied to membrane based water treatment plants to achieve economic operational costs and high treatment efficiency.
Constraining Mechanistic Models Of Indicator Bacteria At Recreational Beaches In Lake Michigan Using Easily Measurable Environmental Variables
Authors: Aaron Wendzel; Phanikumar Mantha
Abstract: Beach closures have significant economic and human health implications and the ability to create and use near-realtime hydrodynamic and transport models that accurately simulate fecal indicator bacteria (FIB) levels at our nation’s recreational beaches is important to effectively managing coastal resources. Here we describe the development and application of an unsteady, three-dimensional hydrodynamic fate and transport model constrained using easily measurable environmental variables such as electrical conductivity (EC) and turbidity. The model was able to accurately simulate observed Escherichi coli concentrations at three beaches in close proximity to the Burns Waterway along the Indiana Dunes National Lakeshore. This model utilized an unstructured grid that has the ability to accurately represent local features in the area, including the complex shoreline and breakwaters that influence hydrodynamics and mixing. This allows for the better prediction of FIB at local beaches reducing human health risks and decreasing the number of unnecessary beach closures.
Human Adenovirus Removal By Hollow Fiber Membranes In A Bench-Scale MBR: The Effect Of Silica Particles And Humic Acid As Model Foulants
Authors: Ziqiang Yin; Volodymyr V. Tarabara; Irene Xagoraraki
Abstract: Membrane bioreactors (MBRs) are rapidly developing as a preferred advanced wastewater treatment technology. Virus removal by MBRs is of concern, since membrane pore sizes can be larger than the size of certain viruses. In this bench-scale study, virus removal experiments were carried out using PVDF hollow fiber (0.22 and 0.45 micron nominal pore sizes) membranes operated under constant flux regime and in the presence of aeration. The permeate flow was recirculated in the feed tank. Silica particles (1-3.5um in diameter) and humic acid were selected as model foulants. Human adenovirus (HAdV) 40 was used as a model virus and quantitative polymerase chain reaction (qPCR) was employed to determine virus concentration. The individual and combined impacts of model foulants on membrane fouling and virus removal were determined and compared. The results indicate that the mixture of silica particles (800ppm) and humic acid (40ppm) can cause severe and fast fouling on both membranes (0.22 and 0.45um), while the fouling is not significant when only each one of the foulants was used alone. The effect of SiO2 alone on virus removal was very small. Presence of humic acid enhanced virus removal, especially with the 0.22um membrane. When membrane filtration is carried out in the mixture of silica particles and humic acid, virus concentrations in the permeate samples were consistently higher than in the feed samples. One potential explanation is that humic acid facilitates virus adsorption on silica particles and subsequently, during filtration, silica particles accumulate on the membrane surface and form a porous layer. Then, viruses are desorbed from the silica particles due to the flux through the porous layer and are detected in the permeate. All data suggest that adsorption plays an essential role in membrane systems regarding to membrane fouling and virus removal.
This work was supported in part by a Strategic Partnership Grant from the Michigan State University Foundation and in part by the National Science Foundation award CBET 1236393.
The Groundwater Recharge Model Base On Grids’ Distributed Parameters
Authors: Jing Zhang; Shu-Guang Li
Abstract: The estimation of net infiltration of water below the root zone plays an important role for quantifying the potential recharge to an underlying water-table aquifer. The net infiltration below the bottom of the root zone is assumed to equal net recharge to an underlying water-table aquifer in many applications of research. Thus, it is necessary to accurately estimate the infiltration flux when quantifying recharge as input to groundwater models. A grid-based model using distributed parameters, deterministic precipitation-runoff and net-infiltration water balance is proposed to calculate the daily net infiltration water to be used as recharge to water-table aquifer modeling.
Precipitation, infiltration, evapotranspiration, drainage and water-content redistribution characterize the root-zone components of the water balance. These parameters are combined with surface-water flow to simulate the daily water balance. Specific input data includes daily climate records (i.e., precipitation and air temperature), the spatially distributed characteristics of drainage-basin and the geology, soil, and vegetation distribution. A set of spatially distributed input variables uniquely assigned to each grid can represented the drainage-basin characteristics.
The State of Michigan is
chosen as case study. The expected outcome will be mapping of net infiltration
at different temporal and spatial scales. In addition, the relationship between
the dynamic net infiltration in Michigan and the global climatic warming would
be obtained by sensitivity analysis. Moreover, the major controls of net
infiltration would be extracted from the model parameters by the methods of
factor analysis and clustering analysis. Then, the empirical results will be
compared to the grid-based modeling technique.