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Browsing by Author "Boardman, Gregory D."

Now showing 1 - 20 of 175
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    Acid-phase and Two-phase Codigestion of FOG in Municipal Wastewater
    Varin, Ross A. III (Virginia Tech, 2013-06-11)
    Acidogenic codigestion of fats, oils, and greases (FOG) was studied at 37"C using suspended sludge digesters operated as sequencing batch reactors (SBRs). Volatile fatty acid (VFA) production was found to increase with larger FOG loading rates, although this increase was insignificant compared the theoretical VFA production from FOG addition. Long chain fatty acids (LCFAs) were found to have accumulated in the reactor vessel in semi-solid balls that were primarily composed of saturated LCFAs. Adding high FOG loadings to an APD not acclimated to LCFAs allowed for a mass balance calculation and resulted in near complete saturation of unsaturated LCFAs and significant accumulation of LCFA material in the digester, which was found to be mostly 16:0, 18:0, and 18:1. While 18:2 and 18:3 LCFAs were nearly completely removed, 18:0 and 14:0 LCFAs were produced, most likely from the degradation of 18:2 and 18:3 LCFAs. The APD pH was found to have a significant impact on the amount of accumulated LCFA material present, with higher pH levels resulting in less accumulated material. Two-phase codigestion of FOG was also studied using an APD followed by gas-phase (GPD) digesters. The two-phase systems were compared by FOG addition to the APD versus GPD. FOG addition to the APD resulted in 88% destruction of LCFAs, whereas FOG addition to the GPD resulted in 95% destruction of LCFAs. Accumulated LCFAs in the APD receiving FOG were composed mostly of stearic acid (18:0). The low pH of the APD is likely the cause of LCFA accumulation due to saturation of unsaturated LCFAs.
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    Acute toxicity of ammonia and nitrite to Pacific White Shrimp (Litopenaeus vannamei) at low salinities
    Schuler, Dominic (Virginia Tech, 2008-04-30)
    The Pacific white leg shrimp, Litopenaeus vannamei, is a potential species for low salinity inland aquaculture. Due to several independent variables, such as species, age, size, salinity and pH, that must be taken into account, there are gaps in the literature pertaining to the toxicity of ammonia and nitrite to shrimp. This study was conducted to investigate the individual and combined effects of ammonia and nitrite on L. vannamei postlarvae (25-45 days old) at 10 ppt salinity, 28 C and a pH of 7.8. The independent variables were salinity, total ammonia as nitrogen (TAN) and nitrite-N (NO₂-N), separately and combined. The TAN experiments were conducted at 18 and 10 ppt salinity while the NO₂-N test was conducted at 10 ppt salinity. Combined TAN and NO2 tests were also conducted at 10 ppt salinity. The LC50 values for TAN at 18 ppt salinity, TAN at 10 ppt salinity, and NO2-N at 10 ppt were observed to be 42.92, 39.72 mg/L (2.26 and 2.09 mg/L unionized ammonia-N), and 153.75 mg/L, respectively. When NO₂- N was adjusted to the LOEC level and TAN concentrations were varied, synergistic effects were observed, with an LC50 calculated to be 28.2 mg/L TAN (1.49 mg/L unionized ammonia-N). However, when the ammonia level was adjusted to the LOEC and nitrite was varied, antagonistic effects were observed with an LC50 calculated to be 163.3 mg/L NO₂-N. The results suggest that further investigations into the combined effects of ammonia and nitrite at varying concentrations and lower salinities will be important in developing "standard operating procedures" for the shrimp industry.
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    Adsorption kinetics for the removal of soluble manganese by oxide- coated filter media
    Hungate, Robert W. (Virginia Tech, 1988-12-05)
    This study was conducted to examine the kinetics of manganese sorption on oxide-coated filter media. Initial experimentation confirmed the findings of other investigators, the Mn²⁺ sorption capacity of oxide-coated media increases as solution pH increases. Further study revealed that uptake rate kinetics could be described by first order kinetics and also increased with increasing solution pH. The addition of free chlorine (HOCl) to solution greatly enhanced Mn²⁺ uptake rate kinetics. Later studies indicated that the oxide coating had very little impact on the physical properties of the media tested. Actual data from a water treatment plant filter confirmed laboratory experimental results by showing that sorption of soluble manganese does indeed occur on oxide-coated filters. The water treatment plant data also suggested that the sorption kinetics were relatively rapid, again upholding laboratory findings. Results from the manganese kinetics and sorption experiments were combined to formulate a theoretical model which would predict manganese breakthrough in a filter, given a known set of loading parameters. Preliminary use of the model indicated that oxide-coated filters could sorb significant quantities of soluble manganese before detectible levels of manganese appear in the effluent.
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    Anaerobic / Aerobic Digestion for Enhanced Solids and Nitrogen Removal
    Banjade, Sarita (Virginia Tech, 2008-12-04)
    Anaerobic digestion of wastewater sludge has widely been in application for stabilization of sludge. With the increase in hauling cost and many environmental and health concerns regarding land application of biosolids, digestion processes generating minimized sludge with better effluent characteristics is becoming important for many public and wastewater utilities. This study was designed to investigate the performance of anaerobic-aerobic-anaerobic digestion of sludge and compare it to anaerobic-aerobic digestion and single stage mesophilic digestion of sludge. Experiments were carried out in three stages: Single-stage mesophilic anaerobic digestion (MAD) 20d SRT; Sequential Anaerobic/Aerobic digestion (Ana/Aer); and Anaerobic/Aerobic/Anaerobic digestion (An/Aer/An). The Anaerobic/Aerobic/Anaerobic digestion of sludge was studied with two options to determine the best option in terms of effluent characteristics. The two sludge withdrawal options were to withdraw effluent from the anaerobic digester (An/Aer/An – A) or withdraw effluent from the aerobic digester (An/Aer/An – B). Different operational parameters, such as COD removal, VS destruction, biogas production, Nitrogen removal, odor removal and dewatering properties of the resulting biosolids were studied and the results were compared among different processes. From the study, it was found that An/Aer/An – B (wastage from aerobic reactor) provided better effluent characteristics than An/Aer/An – A (wastage from anaerobic reactor), Ana/Aer or conventional MAD. The study also shows that the Anaerobic/Aerobic/Anaerobic (An/Aer/An, with wastage from the aerobic or anaerobic digester) digestion of the sludge can improve the biosolids quality by improving the dewatering capabilities, with lower optimum polymer dose, reduced CST and increased cake solid concentration, and reduce the odor generation from the biosolids. Both An/Aer/Ana – A and An/Aer/An – B gave 70% VS removal, compared to 50% with single MAD and 62% with only Ana/Aer. COD removal of both An/Aer/An – A and An/Aer/An – B was 70%, while it was 50% and 66% for single MAD and Ana/Aer respectively. In the aerobic reactors of Ana/Aer and An/Aer/An - B, nitrification and denitrification with removal of nitrogen was observed. The An/Aer/An – B system had more ammonia and TKN removal (70%) than Ana/Aer (64%). The effluent from each stage was analyzed for dewatering ability, cake solid concentration and odor production potential. Compared with a single Ana/Aer system, the extra anaerobic step in An/Aer/An – A and – B reduced polysaccharides in the effluent. The Ana/Aer system released less protein than the conventional MAD system and the addition of the second anaerobic step - especially with system An/Aer/An – B (discharge from aerobic reactor) - greatly reduced protein, resulting in improved dewaterability and less polymer demand. An/Aer/An (both of the options: A and B) had lower CST than single MAD (both 15d and 20d SRT) and Ana/Aer. Compared to Ana/Aer, a reduction of 52% for An/Aer/An – A and 20% for An/Aer/An – B in polymer dose requirement was observed, indicating improved dewatering characteristics. The An/Aer/An – B has higher biosolid cake concentration than MAD or Ana/Aer. The results showed that An/Aer/An (both options: A and B) biosolid had lower odor generation potential than single MAD (15d and 20d SRT) or Ana/Aer. Of all the stages,the An/Aer/An – A and – B system, generated odor which peaked at shorter time and lasted for shorter duration of time.
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    Anaerobic and Combined Anaerobic/Aerobic Digestion of Thermally Hydrolyzed Sludge
    Tanneru, Charan Tej (Virginia Tech, 2009-11-12)
    Sludge digestion has gained importance in recent year because of increasing interest in energy recovery and public concern over the safety of land applied biosolids. Many new alternatives are being researched for reducing excess sludge production and for more energy production. With an increase in solids destruction, the nutrients that are contained in sludge especially nitrogen, are released to solution and can be recycled as part of filtrate or centrate stream. Nitrogen has gained importance because it has adverse effects on ecosystem's as well as human health. NH₄⁺, NO₂⁻, NO₃⁻-, and organic nitrogen are the different forms of nitrogen found in wastewater. While ammonia is toxic to aquatic life, any form of nitrogen can be utilized by cyanobacteria and result in eutrophication. NO₂/NO₃, if consumed by infants through water, can affect the oxygen uptake capability. Hence, removal of nitrogen from wastewater stream before discharging is important. The main purpose of this study was to evaluate the performance of the Cambi process, a thermophylic hydrolysis process used as a pre-treatment step prior to anaerobic digestion. Thermal hydrolysis, as a pre-treatment to anaerobic digestion increases the biological degradation of organic volatile solids and biogas production. The thermal hydrolysis process destroys pathogens and hydrolysis makes the sludge readily available for digestion, while at the same time facilitating a higher degree of separation of solid and liquid phases after digestion. Experiments were conducted in three phases for anaerobic digestion using the Cambi process as pre-treatment. The phases of study includes comparison of two temperatures for thermal hydrolysis (Cambi 150°C and Cambi 170°C), comparison of two solid retention times in anaerobic digestion (15 Day and 20 Day) and comparison of two mesophilic temperatures in anaerobic digestion (37°C and 42°C). Different experimental analyses were conducted for each phase, such as pH, bio-gas production, COD removal, VS destruction, nitrogen removal, odor and dewatering characteristics and the results are compared among all the phases. The second part of the study deals with aerobic digestion of anaerobically digested sludge for effective nitrogen removal and additional VS destruction, COD removal. An aerobic digester is operated downstream to anaerobic digester and is operated with aerobic/anoxic phase for nitrification and de-nitrification. The aerobic/anoxic phases are operated in time cycles which included 40minutes/20minutes, 20minutes/20minutes, full aeration, 10minutes/30minutes, and 12minutes/12minutes. Different time cycles are experimented and aerobic digester is optimized for effective nitrogen removal. 12minutes aerobic and 12minutes anoxic phase gave better nitrogen removal compared to all the cycles. Over all the aerobic digester gave about 92% ammonia removal, 70% VS destruction and 70% COD removal. The oxygen uptake rates (OUR's) in the aerobic digester are measured corresponding to maximum nitrogen removal. The OUR's are found to be close to 60 mg/L during maximum nitrogen removal. The effluent from both anaerobic digester and aerobic digester was collected and analyzed for dewatering capability, cake solids concentration and odor potential.
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    Anaerobic biodegradation of selected organic compounds with and without inhibition of sulfate reducing bacteria
    McBrayer, Tinker R. (Virginia Tech, 1989-02-05)
    The primary objective of this study was to investigate the use of hydrogen as a structural substitute or as a reducing equivalent in the anaerobic biodegradation of methanol, methyl tert-butyl ether (MTBE), toluene, phenol, and 2,4- dichlorophenol. In addition, biodegradation rates of these compounds at various initial concentrations with and without inhibition of sulfate reducing bacteria were determined along with anaerobic biodegradation rate constants for each of the compounds studied. Rates of methanol biodegradation were only slightly altered in molybdate amended microcosms indicating that methanol is a noncompetitive substrate in Blacksburg soil. MTBE biodegradation was slow and followed first order kinetics with respect to initial concentration. Molybdate had no affect on MTBE biodegradation alone, but increased the biodegradation rate in MTBE microcosms which were amended with ethanol. Toluene, phenol, and 2,4-dichlorophenol biodegradation proceeded at two different rate versus initial concentration relationships for lower and upper concentration ranges. Phenol biodegradation followed first order kinetics. The 2,4-dichlorophenol biodegradation rate order varied from 0.78 to 1.75. Monod kinetics were followed by methanol, toluene, and phenol, but not by MTBE, ethanol amended MTBE, or 2,4-dichlorophenol. Addition of molybdate to inhibit sulfate reduction increased the degradation rates more for compounds which may require hydrogen in a structural position (2,4-dichlorophenol, MTBE) than those which require hydrogen for proton reduction (methanol). Biodegradation or recalcitrant compounds may be stimulated by the addition of organics (such as ethanol) which produce hydrogen upon biodegradation.
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    Anaerobic Co-Digestion of High Strength Food Waste with Municipal Sewage Sludge: An assessment of Digester Performance and gas production
    Pathak, Ankit Bidhan (Virginia Tech, 2014-06-06)
    Anaerobic digestion is perhaps the simplest and most widely accepted method for solids and residuals management in the field of wastewater treatment. An emerging trend with regard to anaerobic digestion is the addition of additional organic or industrial wastes rich in degradable material (COD) that can lead to increased methane production and reduce the energy demand of the facility. The objective of this research was to evaluate the effect of adding significant quantities (>20% of feed volume) of High Strength Food Wastes (HSW) to digesters treating conventional municipal sludge by monitoring key parameters such as pH, influent and effluent solids, ammonia, Volatile Fatty Acids (VFAs) and alkalinity. Daily gas production was also closely monitored. Four digesters were set up and exposed to different food waste loading rates. A comparison was drawn between the performance of these reactors, one of which was fed only with sewage sludge and served as the control. If the bacteria in the system are able to metabolize this additional COD, it should show up as an increase in gas production with little or no increase in effluent COD. Ammonia is another crucial parameter that needs to be closely watched as it can have an inhibitory effect on methane production. As part of this study, the impact of addition of free ammonium (simulating high ammonium concentration in the feed sludge or food waste) on digester performance was assessed. The digesters were closely monitored for signs of poor performance or failure.
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    Anaerobic Digestion: Factors Effecting Odor Generation
    Verma, Nitin (Virginia Tech, 2005-07-19)
    Land application of anaerobically stabilized biosolids is a beneficial method of handling the solid residuals from a wastewater treatment plant. One of the main issues that restrict land application of biosolids is nuisance odors associated with biosolids. Despite its importance, few studies have been done to enhance our knowledge of odor causing processes. This study was conducted to evaluate the effects of some factors that have been thought to be linked to odor generation from biosolids. The first part of this study has looked at the role of metals, iron and aluminum in particular, in determining the odor causing processes. The results showed that iron correlated well with headspace organic sulfur odor. In general, as the iron content of sludge increased greater amounts of odorous sulfur gases were produced from dewatered biosolids cakes. Aluminum did not show any relationship with organic sulfur odors. Parameters commonly used for assessing the performance of anaerobic digesters (volatile solids reduction (VSR), residual biological activity (RBA) and effluent volatile fatty acid (VFA) content) also showed no correlation with odors. The second part of the study focused on determining the impact of anaerobic digester solids retention time (SRT) on the odor generation from dewatered biosolids cakes and also on elucidating the nature and impact of the various Extracellular Polymeric Substances (EPS) fractions on odors. The results showed that odors decreased with an increase in the anaerobic digester SRT. VSR and RBA correlated with odors; however, as only one type of sludge was assessed, the conclusions about any relationship may not be universal. The results also showed that sulfur gas generation was a function of EPS material bound to iron, again showing that iron plays an important role in odor generation from dewatered sludge cakes. The third part of the study looked at the effects of advanced digestion processes on odor generation. Digested sludge from acid/gas and temperature phased anaerobic digestion systems were analyzed in the lab. The results show that both acid/gas system and temperature phased digestion had a positive impact on odor generation from dewatered biosolids cake. Comparison of sludge from pancake shaped and egg shaped digesters showed that egg shaped digester was more efficient with regard to odor reduction.
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    Anaerobic/aerobic degradation of a textile dye wastewater
    Loyd, Chapman Kemper (Virginia Tech, 1992-03-05)
    Consumer demands have led to the development of new, more stable textile dyes. These dyes, many of the azo type, are often incompletely degraded/removed in wastewater treatment plants, leading to the discharge of highly colored effluents to rivers and streams. Concerns by downstream users of that water have led to enactment of effluent color and toxicity standards for plants that treat textile dye wastewater. Both anaerobic and aerobic biological degradation of azo dyes have been reported in the literature; the rate and extent of degradation is often quite dye-specific. This research utilized laboratory-scale reactors to investigate the effectiveness of those treatments, both singly and in combination, on two azo dye wastewaters: a textile dyeing and finishing process water and a municipal wastewater consisting predominately of textile dyeing and finishing mill effluents.
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    Anaerobic/aerobic pretreatment of blue crab (Callinectes sapidus) cooker wastewater
    Diz, Harry Richard (Virginia Tech, 1994-10-05)
    Wastewater from the pressure cooking of blue crabs presents a difficult treatment challenge. COD concentrations in the range of 15,000 to 30,000 mg/L are found in this wastewater, with TKN concentrations above 2,000 mg/L. Direct discharge of the wastewater, which is currently allowed, adds nutrients to the Chesapeake Bay, and potentially creates local DO depletion in receiving waters. Anaerobic treatment of this wastewater was studied for the reduction of COD. Nitrification was studied for the conversion of ammonia, present at levels above 1,000 mg/L NH3/NHA4-N, to nitrate for possible denitrification. COD reductions averaging above 11,000 mg/L were found to occur in an upflow anaerobic filter operating with less than a 4 day HRT. Further COD reduction in the aerobic reactor resulted in a final effluent averaging 2,400 to 3,100 mg/L soluble COD with a corresponding BOD₅ of 110 to 340 mg/L. Nitrification proved to be inhibited, perhaps by the high levels of NH₃/NH₄-N in the effluent from the anaerobic stage. Nitrification did occur in a batch study, but only after extended aeration, and depletion of BOD. Non-degradable COD was estimated to be 2,900 mg/L in the anaerobic effluent. Monod model kinetic coefficients for the anaerobic stage were determined on a degradable COD basis to be: k = 0.68 day⁻¹, Ks = 3,500 mg/L (degradable portion), Y = 0.19, and Kd = 0.028 day⁻¹. The effect of the addition of certain trace metals (Fe, Ni, Co, Mo) to the feed was investigated. There was no improvement in COD removal performance, and slight inhibition may have occurred.
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    Analysis and Prevention of Usable Fiber Loss from a Fine Paper Mill
    Barber, Steven Donald (Virginia Tech, 1998-09-17)
    Reducing losses of usable waste fiber from paper mills conserves valuable resources and has the capacity to produce considerable economic returns to the manufacturer. The purpose of this research effort was to evaluate the potential for the prevention of loss and/or recovery of usable waste fiber from paper machines within a fine paper mill. Further, a preliminary evaluation of fiber loss prevention strategies and fiber recovery technologies was conducted. The paper mill in question experienced losses of usable waste fiber to the sewer in amounts approaching, and sometimes exceeding 40 tons/day. An existing database of usable fiber test results was analyzed to determine patterns of fiber loss. Further testing showed that the most significant fiber losses resulted from centrifugal cleaner cones. These cones, designed to remove foreign material from stock, are one step in a series of mechanical cleaning devices in the stock preparation area of the paper mill. Cleaner cone systems on two of the paper machines were found to contribute most significantly to total fiber loss. Contrary to cleaner cone design, the dirt content of fiber rejects from cones experiencing excessive loss was very low. Cleaner cones on other machines operated normally. These rejects were extremely dirty and quantities of fiber were low. These results indicate poor operating efficiency of two of the cleaner cone systems in question. By adding cones where space is available, system capacity and efficiency will increase, fiber losses will decrease, and the dirt content of rejects will increase. This will result in substantial resource and financial savings to the paper mill. Technologies have been developed to recover usable fiber from paper mill sludge. However, prior to further investigation of the use of such innovations at this paper mill, efforts should focus on the reduction of fiber loss from point sources.
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    Analysis of Organic and Inorganic Parameters in Southern Virginia Rivers Following a Coal ash Spill
    Waggener, Keegan Edward (Virginia Tech, 2018-01-23)
    In February 2014, a coal ash spill on Duke Energy's Dan River Plant in Eden, NC released approximately 39,000 tons of coal ash into the Dan River. It took approximately one week to stop the spill. Starting in February 2015, drinking water utilities using the Dan River experienced a series of taste and odor (TandO) events described as "earthy" or "musty". Similar TandO events were not documented before the coal ash spill. This research attempted to understand causes of the TandO events and if the coal ash spill was connected. A variety of water quality analyses were performed on twelve sites from August 2016 to September 2017 on the Dan and Smith Rivers. The Smith River served as the control. From concentrations of coal ash indicators (particularly Ba, Sr, As, V, and Br-), there was a signature of coal ash on the Dan River that was not present on the Smith River. The signature could not be attributed to the coal ash spill, as the signature was present upstream of the spill. Chronic ecosystem toxicity due to metals was low and not significantly different between the Dan and Smith Rivers. No substantial TandO events occurred during the period of this study. All monitored odorants were detected with varying frequencies in both the Dan and Smith Rivers. No significant change in odorant concentration was found above and below the location of the coal ash spill.
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    Anammox-based Technologies for Sustainable Mainstream Wastewater Treatment: Process Development, Microbial Ecology and Mathematical Modeling
    Li, Xiaojin (Virginia Tech, 2018-03-08)
    The nitritation-anammox process is an efficient and cost-effective approach for biological nitrogen removal, but its application in treating mainstream wastewater remains a great challenge. The key objectives of this dissertation are to develop nitritation-anammox process to treat wastewater with low-nitrogen strength, understand the fundamental microbiology, and optimize its operation through experimental studies and mathematic modeling. Chapter 2 showed that the nitritation-anammox process has been successfully developed in an upflow membrane-aerated biofilm reactor, where pure oxygen was delivered via gas-permeable membrane module. Chapter 3 demonstrated that hybrid anaerobic reactor (HAR) could be an effective pretreatment method to provide a relatively low COD/N ratio for nitritation-anammox reactor. In Chapter 4, a novel mathematical model has been proposed to evaluate the minimum DO requirement for the nitritation-anammox reactor to achieve the maximum TN removal under various COD/N scenarios (controlled by HRTHAR). Chapters 5 and 6 designed an OsAMX system by linking nitritation-anammox to forward osmosis to remove the reverse-fluxed ammonium while using ammonium bicarbonate as a draw solute. The microbial community structures and dynamics, spatial distributions in these bioreactors were characterized by high-throughput sequencing and fluorescent in situ hybridization techniques. The studies in this dissertation have demonstrated that nitritation-anammox process is a promising alternative for sustainable mainstream treatment with the appropriate pretreatment approach and operation optimization.
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    Applications of Sensory Analysis for Water Quality Assessment
    Byrd, Julia Frances (Virginia Tech, 2018-01-30)
    In recent years, communities that source raw water from the Dan River experienced two severe and unprecedented outbreaks of unpleasant tastes and odors in their drinking water. During both TandO events strong 'earthy', 'musty' odors were reported, but the source was not identified. The first TandO event began in early February, 2015 and coincided with an algal bloom in the Dan River. The algal bloom was thought to be the cause, but after the bloom dissipated, odors persisted until May 2015. The second TandO in October, 2015 did not coincide with observed algal blooms. On February 2, 2014 approximately 39,000 tons of coal ash from a Duke Energy coal ash pond was spilled into the Dan River near Eden, NC. As there were no documented TandO events before the spill, there is concern the coal ash adversely impacted water quality and biological communities in the Dan River leading to the TandO events. In addition to the coal ash spill, years of industrial and agricultural activity in the Dan River area may have contributed to the TandO events. The purpose of this research was to elucidate causes of the two TandO events and provide guidance to prevent future problems. Monthly water samples were collected from August, 2016 to September, 2017 from twelve sites along the Dan and Smith Rivers. Multivariate analyses were applied to look for underlying factors, spatial or temporal trends in the data. There were no reported TandO events during the project but sensory analysis, Flavor Profile Analysis, characterized earthy/musty odors present. No temporal or spatial trends of odors were observed. Seven earthy/musty odorants commonly associated with TandO events were detected. Odor intensity was mainly driven by geosmin, but no relationship between strong odors and odorants was observed.
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    ARIES Executive Summary
    Jong, Edmund C.; Boardman, Gregory D.; Karmis, Michael E. (Virginia Tech. Virginia Center for Coal and Energy Research, 2019-07-30)
    The following document contains an executive summary of key findings from the Appalachian Research Initiative for Environmental Science (ARIES). Further details for these findings may be found in the referenced peer-reviewed publications and project reports. The ARIES body of work was developed from 2011 to 2016. Thus, published ARIES results will not reflect any evolutions in policy and research that occurred after this timeframe. Although some issues may be different today, the breakthrough research conducted by the ARIES community continues to provide invaluable insights into these areas of interest.
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    ARIES Research Summary
    Jong, Edmund C.; Boardman, Gregory D.; Karmis, Michael E. (Virginia Tech. Virginia Center for Coal and Energy Research, 2019-01-03)
    In the mid-2000s, concerns were raised about the impact of Appalachian coal mining and especially mountaintop mining. These concerns were prompted by various research studies that alleged a direct link between coal mining and various negatively trending aspects of community health. Some studies related coal mining to higher rates of cancer and infant mortality. Other investigations claimed that coal mining perpetuated poverty and harms community character. These alarming reports prompted a significant public outcry that resulted in litigation and regulatory attention toward the coal industry. In response, a number of meetings and strategic sessions were held in 2009 and 2010 to address these concerns. Major Appalachian coal producers, coal associations, and essential coal infrastructure companies participated in these conferences. After rigorous debate, the participants decided to form an independent research program designed to address community concerns through objective, focused research. This program was designated the Appalachian Research Initiative for Environmental Science (ARIES). ARIES would be a research consortium designed to elicit the participation of major research universities across the U.S. The primary objective of this research collaboration would be to investigate the impacts of coal mining and energy production on Appalachian communities. To support this goal, ARIES adopted a research paradigm that delivered objective, robust, and transparent results though the support of industry. This paradigm was composed of four core principles: 1. Independent research conducted at universities 2. Wide dissemination of results through peer-reviewed publications 3. Realistic timeframes for research and reporting 4. Applying sound scientific principles
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    Availability and distribution of nitrogen and phosphorus from sewage sludge in the plant-soil-water continuum
    Scott, James D. (Virginia Tech, 1987-05-05)
    Research was conducted in 1984 and 1985 to determine N and P availabilities for barley (Hordeum vulgare L.) and com ( Zea mays L.) grown on four sludge-amended soils. Tests were conducted on the Acredale silt loam (Typic Ochraquall), Bojac loamy sand (Typic Hapludult), Davidson clay loam (Rhodic Paleudult), and Groseclose silt loam (Typic Hapludult) soils. An aerobically·digested sewage sludge from a sewage treatment plant with major industrial irrputs was applied at rates of 0, 42, and 84 dry Mg ha' 1 on the poorly-drained Acredale soil. Rates of 0, 42, 84, 126, 168, and 210 dry Mg ha'1 were applied on the well-drained Bojac, Davidson, and Groseclose soils. The 210 dry Mg haâ 1 sludge rate supplied 3300 and 6600 kg of N and P haâ 1, respectively. A 14-day anaerobic N incubation study indicated that mirreralization varied from approximately nine to four percent of sludge N from the 42 to 210 Mg haâ 1 application rates, respectively. Sludge application increased N uptake (rz = 0.98** to 0.99**) by the 1984 com grown on the three well-drained soils. Nitrogen balance data indicated that quantities of unrecovered N ranged from six to 21 percent where sludge was applied.
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    Benthic Macroinvertebrate Susceptibility to Trout Farm Effluents
    Roberts, Lenn Darrell (Virginia Tech, 2005-08-30)
    The direct effects of a Virginia trout farm on benthic macroinvertebrates were examined using multiple approaches. Static laboratory tests with the amphipod, Hyallela azteca, were conducted with exposures to water taken from a spring, effluent above a sedimentation basin, and effluent below a sedimentation basin. On-site mesocosms were constructed to expose previously colonized artificial substrates to the same treatments as the laboratory tests. Flat-headed mayflies were also collected from a nearby stream and transported to the mesocosms for a 10 day exposure. There was no significant difference between treatments in the laboratory tests after 20 days, but after 28 days the control was significantly lower than the above sedimentation basin treatment in one test. In the multispecies field tests, a clear decrease in total invertebrate abundance and EPT abundance was seen in the effluent treatments compared to the spring water treatments, with a slight improvement in survival in the treatment below the sedimentation basin. However, only total invertebrate abundance after 21 days produced statistically significant differences. A significant difference was detected between the effluent and the spring treatments in the flat-headed mayfly field test. We suggest that the effects seen in this study do not explain the lack of taxa richness in the receiving stream. The main cause of mortality from trout effluents appears to be solids accumulating upon the organisms, and sedimentation basins should be effective best management practices for protecting macroinvertebrates.
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    Biodegradation of 2,4-Dinitrotoluene in the Waste Streams of a Munitions Plant
    Christopher, Heidi Jandell (Virginia Tech, 1998-09-15)
    Wastewater from the manufacture of propellants typically contains 2,4-dinitrotoluene (DNT), a suspected animal carcinogen. Previous studies have indicated that DNT is aerobically biodegradable. However, inconsistent removal of DNT during aerobic treatment has been observed at a munitions wastewater treatment plant, necessitating the use of activated carbon pre-treatment. The objective of this study was to evaluate the effect of nutrient and cosubstrate amendments on the rate and extent of DNT removal. Addition of ethanol (100-500 mg/l) and phosphate (0.8-3.3 mg/l) significantly accelerated the rate of aerobic DNT (0.3-5.6 mg/l) biodegradation. Addition of phosphate alone also increased the rate of DNT degradation, but to a lesser degree. The presence of ethyl ether, another substrate commonly found in munitions plant wastewater, had comparatively little effect on the rate of DNT removal. Interruptions in the DNT manufacturing process can result in DNT being absent from the munitions plant wastewater for extended periods. The effect of such interruptions was evaluated in semi-continuously operated reactors, fed daily with phosphate-amended wastewater, at a hydraulic residence time of 3 days. DNT removal resumed without a lag even after it was absent from the feed for periods up to 15 days. During aerobic biodegradation of DNT, reduction to 4-amino-2-nitrotoluene and 2-amino-4-nitrotoluene was consistently observed, with reduction at the para position predominating. The highest level of aminonitrotoluene formation was 23% of the total DNT degraded. Aminonitrotoluene isomers were consumed shortly after they formed in the semi-continuously operated reactors, confirming the potential for degradation of these metabolites. Although the aminonitrotoluene isomers are not currently regulated, their presence in treated munitions wastewater is a concern due to possible toxicity.
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    The biodegradation of valeric, butyric, propionic and acetic acids in anoxic, subsurface, soil environments
    Sandberg, Scott A. (Virginia Polytechnic Institute and State University, 1988)
    The biodegradation potential of two subsurface soils was characterized by monitoring the biodegradation of short-chain fatty acids in anaerobic soil microcosms. Valerate, butyrate, propionate, and acetate concentrations were monitored independently using separate microcosms. The effect of sulfate on the microbial communities was also investigated. One soil, from Newport News, Virginia, consisted of a sandy loam collected beneath a low lying, grassy field. The microcosms containing the soil were characterized by: a neutral pH, the utilization of sulfate with concomitant precipitation of iron sulfide , an increase in the degradation rate as a result of sulfate addition, and a production of bicarbonate directly related to acid mineralization. Another soil, from Blacksburg, Virginia, consisted of a silty-clay collected beneath a wooded hilltop. Microcosms containing the soil were characterized by : a pH between 4 and 5, little sulfate utilization with no visible iron sulfide precipitation, an increase in degradation rates upon the addition of sulfate, and little or no accumulation of bicarbonate. These results indicate that short-chain fatty acids are readily degraded in subsurface anaerobic soil systems and that these rates are dependent on the availability of electron acceptors and the diversity of the indigenous population.