This webinar will briefly review the theory behind isotopic effects, it will explain the units used to characterize the ratio of isotopes, and it will discuss the simple mathematics that can relate the shift in the ratio to the extent of degradation. Then the webinar will illustrate an approach to estimate rate constants for natural biodegradation of contaminants in ground water. The isotope analysis will be used to estimate the extent of natural biodegradation of MTBE at a gasoline spill site. The extent of biodegradation will be combined with the hydrological parameters at the site to estimate rate constants for biodegradation.
The webinar will conclude with a number of cautions and warnings. Heterogeneity in flow paths in the aquifer and proximity to NAPL or other source of contamination to ground water can substantially confuse the interpretation of stable isotope data. Both these conditions cause the isotope analysis to underestimate the extent of degradation. Heterogeneity in the rate of biodegradation can produce substantial errors in the forecasts of plume behavior. The webinar will provide recommendations to deal with the effects of heterogeneity in rates of biodegradation.
U.S. EPA has released A Guide for Assessing Biodegradation and Source Identification of Organic Ground Water Contaminants using Compound Specific Isotope Analysis (CSIA) [EPA 600/R-08/148 | December 2008 | www.epa.gov/ada]. The Guide provides recommendations for sample collection, sample preservation, and sample analysis; recommendations on QA/QC issues; details on calculations; and a catalogue of expected initial values for the ratios of 13C to 12C in organic compounds such as TCE and PCE. The Guide also illustrates in detail the process to use isotope ratio data to estimate rate constants for degradation of organic compounds in ground water.
The document summarizes a study conducted by an intern for Charleston Waterkeeper to determine if copper-based marine antifouling paints are a significant source of copper contamination in sediments near marinas and boatyards in Charleston Harbor. Samples were collected from 3 marinas/boatyards and a control site and tested for copper concentration. Statistical analysis found significantly higher copper levels in sediments closer to marinas/boatyards, suggesting antifouling paints are a likely source of the contamination. Future recommendations include further studies, monitoring, and promoting alternatives to copper-based paints.
The document analyzes the quality of greywater before and after treatment from four sites in Costa Rica. Samples were collected and tested for various water quality parameters like pH, conductivity, dissolved solids, nitrogen and more both before and after treatment. The results found that treatment improved water quality for most parameters, though some sites showed higher levels of certain contaminants after treatment likely due to design flaws or other site-specific factors.
Quantification of Copper in Surface Sediment Samples via Flame Atomic Absorpt...Austin Tang
The document summarizes a study that quantified copper concentrations in sediment samples from harbors and beaches via flame atomic absorption spectroscopy. Sediment samples were collected from Alameda and Santa Cruz harbors and beaches and analyzed for copper content. Results showed that all harbor samples had copper concentrations between the EPA's effects range low and median guidelines, while all beach samples were below the low effects range. There were statistically higher copper levels found in Santa Cruz harbor sediments compared to Alameda harbor, with a potential correlation between higher copper near the inner harbor at Santa Cruz.
The document analyzes variation in physiochemical parameters along part of the Dutch Canal in Sri Lanka which receives effluent from shrimp farms. Water samples from five sites showed higher levels of chlorophyll a, turbidity, pH, ammonia, phosphate and biological oxygen demand at certain sites indicating impact from farming activities. The study concludes the receiving water quality is negatively impacted especially around Udappuwa, Madurankuliya and Muthupanthiya and recommends complementary treatment systems and awareness programs for resource users.
The document summarizes research on measuring concentrations of trace metals in water samples from the Ialomița and Prut Rivers in Romania. Samples were taken at various points along the rivers and during different seasons. Techniques like ICP-AES and differential pulse anodic stripping voltammetry using a mercury film electrode were used to detect metals like iron, selenium, copper, zinc, lead, cadmium, mercury, and arsenic. The results showed seasonal variations in metal concentrations and bioaccumulation in aquatic organisms.
This document summarizes a study that used dissolved carbon dioxide (CO2(aq)) concentrations to predict baseline carbon isotope (δ13C) signatures in lake food webs. The researchers developed an isotopic fractionation model showing that δ13C values in phytoplankton and zooplankton were consistent with measured CO2(aq) levels. Measured and modeled δ13C values were highly correlated. This relationship allows using CO2(aq) as a proxy to estimate baseline δ13C and its variation over time, supplementing direct isotope measurements. The model improves understanding of factors influencing isotopic signatures at the base of lake food webs.
The students cultivated two cultures of sulfur-utilizing bacteria from pond water using different reactor designs. They recorded pH, alkalinity, and optical density over six days as indicators of sulfur oxidation activity. Visual observation showed growth of pink/orange bacteria in the photosynthetic reactor and grey/orange bacteria in the non-photosynthetic reactor, pointing to growth of sulfur-utilizing Chromatiales and Thiobacillus bacteria. The data trends suggested the sulfur substrate was depleted after two days, explaining the stability of measured values over time.
The document summarizes a study conducted by an intern for Charleston Waterkeeper to determine if copper-based marine antifouling paints are a significant source of copper contamination in sediments near marinas and boatyards in Charleston Harbor. Samples were collected from 3 marinas/boatyards and a control site and tested for copper concentration. Statistical analysis found significantly higher copper levels in sediments closer to marinas/boatyards, suggesting antifouling paints are a likely source of the contamination. Future recommendations include further studies, monitoring, and promoting alternatives to copper-based paints.
The document analyzes the quality of greywater before and after treatment from four sites in Costa Rica. Samples were collected and tested for various water quality parameters like pH, conductivity, dissolved solids, nitrogen and more both before and after treatment. The results found that treatment improved water quality for most parameters, though some sites showed higher levels of certain contaminants after treatment likely due to design flaws or other site-specific factors.
Quantification of Copper in Surface Sediment Samples via Flame Atomic Absorpt...Austin Tang
The document summarizes a study that quantified copper concentrations in sediment samples from harbors and beaches via flame atomic absorption spectroscopy. Sediment samples were collected from Alameda and Santa Cruz harbors and beaches and analyzed for copper content. Results showed that all harbor samples had copper concentrations between the EPA's effects range low and median guidelines, while all beach samples were below the low effects range. There were statistically higher copper levels found in Santa Cruz harbor sediments compared to Alameda harbor, with a potential correlation between higher copper near the inner harbor at Santa Cruz.
The document analyzes variation in physiochemical parameters along part of the Dutch Canal in Sri Lanka which receives effluent from shrimp farms. Water samples from five sites showed higher levels of chlorophyll a, turbidity, pH, ammonia, phosphate and biological oxygen demand at certain sites indicating impact from farming activities. The study concludes the receiving water quality is negatively impacted especially around Udappuwa, Madurankuliya and Muthupanthiya and recommends complementary treatment systems and awareness programs for resource users.
The document summarizes research on measuring concentrations of trace metals in water samples from the Ialomița and Prut Rivers in Romania. Samples were taken at various points along the rivers and during different seasons. Techniques like ICP-AES and differential pulse anodic stripping voltammetry using a mercury film electrode were used to detect metals like iron, selenium, copper, zinc, lead, cadmium, mercury, and arsenic. The results showed seasonal variations in metal concentrations and bioaccumulation in aquatic organisms.
This document summarizes a study that used dissolved carbon dioxide (CO2(aq)) concentrations to predict baseline carbon isotope (δ13C) signatures in lake food webs. The researchers developed an isotopic fractionation model showing that δ13C values in phytoplankton and zooplankton were consistent with measured CO2(aq) levels. Measured and modeled δ13C values were highly correlated. This relationship allows using CO2(aq) as a proxy to estimate baseline δ13C and its variation over time, supplementing direct isotope measurements. The model improves understanding of factors influencing isotopic signatures at the base of lake food webs.
The students cultivated two cultures of sulfur-utilizing bacteria from pond water using different reactor designs. They recorded pH, alkalinity, and optical density over six days as indicators of sulfur oxidation activity. Visual observation showed growth of pink/orange bacteria in the photosynthetic reactor and grey/orange bacteria in the non-photosynthetic reactor, pointing to growth of sulfur-utilizing Chromatiales and Thiobacillus bacteria. The data trends suggested the sulfur substrate was depleted after two days, explaining the stability of measured values over time.
This document describes a study that aimed to develop a method to determine isoflavones in the sea anemone Aiptasia pallida using solid phase extraction (SPE) and gas chromatography-mass spectrometry (GC-MS). SPE was used to isolate analytes from symbiotic and aposymbiotic anemone seawater. GC-MS analysis with different solvents like methanol, hexane, and dichloromethane showed minor peaks in seawater samples but results were inconclusive. Derivatization of samples with BSTFA prior to GC-MS produced distinguishable peaks, but the method needs further optimization to better separate peaks and identify specific isoflavones. More experimentation is also needed to
Tiff Hilton, “Manganese—Misunderstood, Mis-Regulated, & Mistaken for a Problem”Michael Hewitt, GISP
The document discusses the establishment and goals of the Clean Water Act to protect surface water quality in the US. It notes that while the Act aims to reduce pollutant discharges and restore water integrity, the treatment requirements for manganese have unintended consequences. Specifically, targeting manganese requires highly alkaline conditions that increase dissolved solids, osmotic pressure, and sludge volumes. It can also cause aluminum, which is toxic, to resolubilize. The document argues that manganese itself is not generally toxic at levels found in mine drainage and that alternative regulatory approaches are needed to avoid problems stemming from over-treatment.
TWCA Annual Convention: Optimizing Slime Control Chemical Feed in TRWD Raw Wa...TWCA
This presentation discusses optimizing slime control and chemical feed in the raw water pipelines of Tarrant Regional Water Districts. It presents results from bench-scale and full-scale testing to evaluate chloramine decay and the impact of nitrifying bacteria in the pipelines. The testing showed that higher chlorine to nitrogen ratios, lower pH levels, and the presence of nitrifying bacteria increased chloramine decay. It also showed chloramine loss from nitrification occurring in the pipelines. The presentation recommends improvements to existing chemical systems and designing new chloramine feed systems to better control slime and protect the pipelines.
The document summarizes research comparing the disinfection of wastewater using peracetic acid (PAA) and sodium hypochlorite. It discusses two case studies - jar testing of PAA and sodium hypochlorite at a wastewater facility in Cincinnati, and a study comparing the two disinfectants at a combined sewer overflow facility in Steubenville, Ohio. The research found that PAA was generally as effective as sodium hypochlorite at inactivating bacteria, but required a higher dose. PAA also produced fewer harmful byproducts and had lower aquatic toxicity than sodium hypochlorite. An ongoing study is evaluating the two disinfectants further at a CSO facility in
Tsvaygboym, J Phys Chem C 2008 v112 pp 695-700nanotech2masses
This document summarizes research on the reaction of single-walled carbon nanotubes (SWNTs) with organic peroxides. The main findings are:
1) SWNTs induce the decomposition of benzoyl peroxide, p-methoxybenzoyl peroxide, phthaloyl peroxide, and trifluoroacetyl peroxide through single electron transfer, accelerating their decomposition rates.
2) Phthaloyl peroxide showed the greatest functionalization of SWNTs of the four peroxides tested.
3) t-Butoxy radicals were found to add to SWNTs, but SWNTs did not inhibit the autoxidation of cumene by alkylper
This document discusses new technologies for improving irrigation water productivity and use efficiency. It describes several technologies being tested and implemented in EU and India projects, including:
- Partial root drying (PRD) irrigation, which saves water by only irrigating half the root zone. Tests found PRD used 15-28% less water than regular irrigation while maintaining equal or similar yields.
- Scintillometers and eddy covariance systems, which directly measure actual evapotranspiration as an alternative to estimating crop water requirements using reference evapotranspiration and crop coefficients. Tests found actual evapotranspiration was 45-35% of estimated values.
- Cosmic-ray soil moisture sensors, which non-inv
Nutrient Management in Everglades Agricultural Area (EAA) CanalsJaya Das
The Everglades wetland is world renowned for its unique hydrogeology, flora and fauna and its scenic beauty. It is a 'World Heritage site' and an 'International Biosphere Reserve'. It's trophic status has come under threat from nutrient inputs from multiple sources. My research attempted to answer critical questions regarding the characteristics, behavior, transportability of sediments along with the flux and fate of Phosphorus in Everglades Agricultural Area canals.
This document contains 7 questions from an environmental engineering homework assignment. The questions involve calculating BOD levels and theoretical oxygen demand of ethanol in wastewater. Additional questions calculate TSS, VSS, TDS and FDS levels based on compound concentrations. Other questions determine the fraction of maximum oxygen consumption after 5 days, the rate constant and half-life for an ultraviolet ozonation reaction, and the monthly chlorine usage for a water treatment plant.
Study of desalination processes of seawater from the desalination plant of La...journal ijrtem
: The use of water for food purposes requires excellent physicochemical quality. To contribute to
the control of water quality. Water treated by reverse osmosis is aggressive and demineralize can not be used
directly as a source of drinking water. The objective of this work is to study, physics-chemical analyzes of raw
water, pretreated osmosis and treated (permeate) and produced water (reservoir) at the desalination plant of
seawater Laayoune (SDL), located in southern Morocco. For this, we have followed several qualitative
parameters such as pH, conductivity, turbidity.
The document discusses proposed improvements to the circulating water treatment system at NLC TPS II power plant. It analyzes water parameters from the current system and identifies high hardness, alkalinity, dissolved solids and oxygen that promote corrosion and scaling. A new treatment system is proposed using increased chlorine dosing to control microbes, along with corrosion and scale inhibitors. Annual chemical consumption and costs are estimated for different cycles of concentration to reduce specific water consumption below 3.5 m3/MWh. Improving the treatment process aims to control corrosion, scaling and fouling in the circulating water system.
This document summarizes a university student's investigation into desalination and its brine waste. It provides background on desalination processes like reverse osmosis and multi-stage flash distillation. These produce brine waste that is more concentrated than seawater and can harm coastal ecosystems if discharged untreated. The document examines environmental impacts like altered ecosystems and erosion from brine discharge. It then evaluates potential solutions like precipitating silver chloride from brine or electrolyzing sodium chloride to produce useful byproducts. The student concludes electrolysis of sodium chloride is the best option as the gases produced could be sold to offset costs while lowering brine chlorine levels and fossil fuel use.
The document presents the results of a life cycle assessment comparing the environmental impacts of water quality from non-potable water reuse and energy recovery using anaerobic and aerobic treatment trains. It finds that a mainstream anaerobic process has the potential to be more sustainable than conventional aerobic treatment, especially when optimized for maximum biogas recovery and minimum energy consumption. Further experimental work is recommended to better realize the environmental benefits of anaerobic nutrient removal technologies.
The document discusses next generation wastewater treatment approaches at multiple scales from individual buildings to entire watersheds. At the building scale, technologies like greywater treatment and rainwater harvesting are discussed. At the cluster scale, technologies like extracting clean water from wastewater and energy extraction from organics are proposed. Finally, the catchment scale examines resource recovery opportunities at centralized wastewater treatment facilities through incremental process improvements.
Activated carbon and biochar additions improved nitrate removal efficiency in denitrifying woodchip bioreactors, especially at low temperatures below 10°C. Woodchips amended with activated carbon or biochar had higher carbon-to-nitrogen ratios and reduced carbon losses compared to woodchips alone. While woodchips alone or with activated carbon effectively removed phosphates, biochar additions risked releasing phosphates and other inorganic elements into outflow. Activated carbon shows potential to develop more efficient bioreactors with prolonged longevity and higher nutrient removal capacity than woodchips alone.
This document summarizes a master's thesis project studying methane production and carbon cycling in Georgetown Lake, Montana. Previous work found the lake to be eutrophic with anoxic conditions below 6 meters depth. The current study aims to identify and quantify methane in the lake water and sediments using GC-MS and CRDS analysis. Depth profiles show increasing methane and reducing conditions near the redox boundary. Preliminary calculations estimate 109 moles of methane released from the lake during spring ice-off.
Building Soil Carbon: Benefits, Possibilities, and ModelingCarbon Coalition
Dr Jeff Baldock, from CSIRO Land & Water, is a central figure in soil carbon science in Australia. His views count because they indicate the centre of gravity in official thinking, such is his influence. Jeff is a mentor and a friend of the soil carbon movement.
Predicting Operational Life of ZVI 2012James Peale
This document summarizes an analysis to predict the operational life of zero-valent iron (ZVI) used in an in situ chemical reduction (ISCR)-enhanced bioremediation system to treat trichloroethylene (TCE) dense non-aqueous phase liquid (DNAPL) at a contaminated site. Regression and geochemical modeling of groundwater data estimated the ZVI would be consumed within 10 to 60 years through reactions with water, chlorinated solvents, and other compounds. While long-term monitoring is needed to verify the predictions, the analysis suggests the ZVI-based system could provide remediation for decades, similar to anticipated timeframes for pump-and-treat systems. Further data collection will
This document provides information on power and steam generation facilities and operations at an oil refinery. It includes details on steam generation equipment and capacities, power generation assets including gas turbines and steam turbines, and summaries of electrical and steam distribution systems. It also summarizes the refinery's water management systems including sources of raw water, water treatment processes, and parameters for treated cooling water.
Lessons learned from injecting liquid activated carbon suspensionAntea Group
Three gas station sites in California were selected for pilot tests of injecting liquid activated carbon suspension to remediate contaminated groundwater. At the first site in San Jose, substantial contaminants desorbed initially but then total petroleum hydrocarbons declined over 60 days and stabilized. The second site in Oakland showed decreases in benzene and other contaminants within 2-3 months, meeting remedial goals. Lessons learned included that direct push injection may not distribute as expected, biostimulation aids carbon treatment, and substantial reductions are possible within months with the right conditions.
Application on Semi-aerobic Landfill. Technology in in Tropical Climate: Lysi...CRL Asia
Presentation file on Application on Semi-aerobic Landfill. Technology in in Tropical Climate: Lysimeter experiment of Thailand (Created: SWGA Chart Chiemchaisri)
The document summarizes testing of a gas transfer membrane (GTM) unit for removing carbon dioxide and dissolved oxygen from makeup water at a nuclear power plant. Key findings from the test include:
1) The GTM unit achieved 78-95% removal of dissolved oxygen and 65-95% removal of carbon dioxide from the makeup water feed.
2) Removing these dissolved gases reduces ion exchange resin loading and usage of deoxygenation chemicals downstream.
3) Over 2.5 million gallons of makeup water were treated during the four month test period, demonstrating the viability of GTM technology for industrial-scale gas removal.
This document describes a study that aimed to develop a method to determine isoflavones in the sea anemone Aiptasia pallida using solid phase extraction (SPE) and gas chromatography-mass spectrometry (GC-MS). SPE was used to isolate analytes from symbiotic and aposymbiotic anemone seawater. GC-MS analysis with different solvents like methanol, hexane, and dichloromethane showed minor peaks in seawater samples but results were inconclusive. Derivatization of samples with BSTFA prior to GC-MS produced distinguishable peaks, but the method needs further optimization to better separate peaks and identify specific isoflavones. More experimentation is also needed to
Tiff Hilton, “Manganese—Misunderstood, Mis-Regulated, & Mistaken for a Problem”Michael Hewitt, GISP
The document discusses the establishment and goals of the Clean Water Act to protect surface water quality in the US. It notes that while the Act aims to reduce pollutant discharges and restore water integrity, the treatment requirements for manganese have unintended consequences. Specifically, targeting manganese requires highly alkaline conditions that increase dissolved solids, osmotic pressure, and sludge volumes. It can also cause aluminum, which is toxic, to resolubilize. The document argues that manganese itself is not generally toxic at levels found in mine drainage and that alternative regulatory approaches are needed to avoid problems stemming from over-treatment.
TWCA Annual Convention: Optimizing Slime Control Chemical Feed in TRWD Raw Wa...TWCA
This presentation discusses optimizing slime control and chemical feed in the raw water pipelines of Tarrant Regional Water Districts. It presents results from bench-scale and full-scale testing to evaluate chloramine decay and the impact of nitrifying bacteria in the pipelines. The testing showed that higher chlorine to nitrogen ratios, lower pH levels, and the presence of nitrifying bacteria increased chloramine decay. It also showed chloramine loss from nitrification occurring in the pipelines. The presentation recommends improvements to existing chemical systems and designing new chloramine feed systems to better control slime and protect the pipelines.
The document summarizes research comparing the disinfection of wastewater using peracetic acid (PAA) and sodium hypochlorite. It discusses two case studies - jar testing of PAA and sodium hypochlorite at a wastewater facility in Cincinnati, and a study comparing the two disinfectants at a combined sewer overflow facility in Steubenville, Ohio. The research found that PAA was generally as effective as sodium hypochlorite at inactivating bacteria, but required a higher dose. PAA also produced fewer harmful byproducts and had lower aquatic toxicity than sodium hypochlorite. An ongoing study is evaluating the two disinfectants further at a CSO facility in
Tsvaygboym, J Phys Chem C 2008 v112 pp 695-700nanotech2masses
This document summarizes research on the reaction of single-walled carbon nanotubes (SWNTs) with organic peroxides. The main findings are:
1) SWNTs induce the decomposition of benzoyl peroxide, p-methoxybenzoyl peroxide, phthaloyl peroxide, and trifluoroacetyl peroxide through single electron transfer, accelerating their decomposition rates.
2) Phthaloyl peroxide showed the greatest functionalization of SWNTs of the four peroxides tested.
3) t-Butoxy radicals were found to add to SWNTs, but SWNTs did not inhibit the autoxidation of cumene by alkylper
This document discusses new technologies for improving irrigation water productivity and use efficiency. It describes several technologies being tested and implemented in EU and India projects, including:
- Partial root drying (PRD) irrigation, which saves water by only irrigating half the root zone. Tests found PRD used 15-28% less water than regular irrigation while maintaining equal or similar yields.
- Scintillometers and eddy covariance systems, which directly measure actual evapotranspiration as an alternative to estimating crop water requirements using reference evapotranspiration and crop coefficients. Tests found actual evapotranspiration was 45-35% of estimated values.
- Cosmic-ray soil moisture sensors, which non-inv
Nutrient Management in Everglades Agricultural Area (EAA) CanalsJaya Das
The Everglades wetland is world renowned for its unique hydrogeology, flora and fauna and its scenic beauty. It is a 'World Heritage site' and an 'International Biosphere Reserve'. It's trophic status has come under threat from nutrient inputs from multiple sources. My research attempted to answer critical questions regarding the characteristics, behavior, transportability of sediments along with the flux and fate of Phosphorus in Everglades Agricultural Area canals.
This document contains 7 questions from an environmental engineering homework assignment. The questions involve calculating BOD levels and theoretical oxygen demand of ethanol in wastewater. Additional questions calculate TSS, VSS, TDS and FDS levels based on compound concentrations. Other questions determine the fraction of maximum oxygen consumption after 5 days, the rate constant and half-life for an ultraviolet ozonation reaction, and the monthly chlorine usage for a water treatment plant.
Study of desalination processes of seawater from the desalination plant of La...journal ijrtem
: The use of water for food purposes requires excellent physicochemical quality. To contribute to
the control of water quality. Water treated by reverse osmosis is aggressive and demineralize can not be used
directly as a source of drinking water. The objective of this work is to study, physics-chemical analyzes of raw
water, pretreated osmosis and treated (permeate) and produced water (reservoir) at the desalination plant of
seawater Laayoune (SDL), located in southern Morocco. For this, we have followed several qualitative
parameters such as pH, conductivity, turbidity.
The document discusses proposed improvements to the circulating water treatment system at NLC TPS II power plant. It analyzes water parameters from the current system and identifies high hardness, alkalinity, dissolved solids and oxygen that promote corrosion and scaling. A new treatment system is proposed using increased chlorine dosing to control microbes, along with corrosion and scale inhibitors. Annual chemical consumption and costs are estimated for different cycles of concentration to reduce specific water consumption below 3.5 m3/MWh. Improving the treatment process aims to control corrosion, scaling and fouling in the circulating water system.
This document summarizes a university student's investigation into desalination and its brine waste. It provides background on desalination processes like reverse osmosis and multi-stage flash distillation. These produce brine waste that is more concentrated than seawater and can harm coastal ecosystems if discharged untreated. The document examines environmental impacts like altered ecosystems and erosion from brine discharge. It then evaluates potential solutions like precipitating silver chloride from brine or electrolyzing sodium chloride to produce useful byproducts. The student concludes electrolysis of sodium chloride is the best option as the gases produced could be sold to offset costs while lowering brine chlorine levels and fossil fuel use.
The document presents the results of a life cycle assessment comparing the environmental impacts of water quality from non-potable water reuse and energy recovery using anaerobic and aerobic treatment trains. It finds that a mainstream anaerobic process has the potential to be more sustainable than conventional aerobic treatment, especially when optimized for maximum biogas recovery and minimum energy consumption. Further experimental work is recommended to better realize the environmental benefits of anaerobic nutrient removal technologies.
The document discusses next generation wastewater treatment approaches at multiple scales from individual buildings to entire watersheds. At the building scale, technologies like greywater treatment and rainwater harvesting are discussed. At the cluster scale, technologies like extracting clean water from wastewater and energy extraction from organics are proposed. Finally, the catchment scale examines resource recovery opportunities at centralized wastewater treatment facilities through incremental process improvements.
Activated carbon and biochar additions improved nitrate removal efficiency in denitrifying woodchip bioreactors, especially at low temperatures below 10°C. Woodchips amended with activated carbon or biochar had higher carbon-to-nitrogen ratios and reduced carbon losses compared to woodchips alone. While woodchips alone or with activated carbon effectively removed phosphates, biochar additions risked releasing phosphates and other inorganic elements into outflow. Activated carbon shows potential to develop more efficient bioreactors with prolonged longevity and higher nutrient removal capacity than woodchips alone.
This document summarizes a master's thesis project studying methane production and carbon cycling in Georgetown Lake, Montana. Previous work found the lake to be eutrophic with anoxic conditions below 6 meters depth. The current study aims to identify and quantify methane in the lake water and sediments using GC-MS and CRDS analysis. Depth profiles show increasing methane and reducing conditions near the redox boundary. Preliminary calculations estimate 109 moles of methane released from the lake during spring ice-off.
Building Soil Carbon: Benefits, Possibilities, and ModelingCarbon Coalition
Dr Jeff Baldock, from CSIRO Land & Water, is a central figure in soil carbon science in Australia. His views count because they indicate the centre of gravity in official thinking, such is his influence. Jeff is a mentor and a friend of the soil carbon movement.
Predicting Operational Life of ZVI 2012James Peale
This document summarizes an analysis to predict the operational life of zero-valent iron (ZVI) used in an in situ chemical reduction (ISCR)-enhanced bioremediation system to treat trichloroethylene (TCE) dense non-aqueous phase liquid (DNAPL) at a contaminated site. Regression and geochemical modeling of groundwater data estimated the ZVI would be consumed within 10 to 60 years through reactions with water, chlorinated solvents, and other compounds. While long-term monitoring is needed to verify the predictions, the analysis suggests the ZVI-based system could provide remediation for decades, similar to anticipated timeframes for pump-and-treat systems. Further data collection will
This document provides information on power and steam generation facilities and operations at an oil refinery. It includes details on steam generation equipment and capacities, power generation assets including gas turbines and steam turbines, and summaries of electrical and steam distribution systems. It also summarizes the refinery's water management systems including sources of raw water, water treatment processes, and parameters for treated cooling water.
Lessons learned from injecting liquid activated carbon suspensionAntea Group
Three gas station sites in California were selected for pilot tests of injecting liquid activated carbon suspension to remediate contaminated groundwater. At the first site in San Jose, substantial contaminants desorbed initially but then total petroleum hydrocarbons declined over 60 days and stabilized. The second site in Oakland showed decreases in benzene and other contaminants within 2-3 months, meeting remedial goals. Lessons learned included that direct push injection may not distribute as expected, biostimulation aids carbon treatment, and substantial reductions are possible within months with the right conditions.
Application on Semi-aerobic Landfill. Technology in in Tropical Climate: Lysi...CRL Asia
Presentation file on Application on Semi-aerobic Landfill. Technology in in Tropical Climate: Lysimeter experiment of Thailand (Created: SWGA Chart Chiemchaisri)
The document summarizes testing of a gas transfer membrane (GTM) unit for removing carbon dioxide and dissolved oxygen from makeup water at a nuclear power plant. Key findings from the test include:
1) The GTM unit achieved 78-95% removal of dissolved oxygen and 65-95% removal of carbon dioxide from the makeup water feed.
2) Removing these dissolved gases reduces ion exchange resin loading and usage of deoxygenation chemicals downstream.
3) Over 2.5 million gallons of makeup water were treated during the four month test period, demonstrating the viability of GTM technology for industrial-scale gas removal.
This presentation describes the operation and application of the Waters APGC (Atmospheric Pressure Gas Chromatography) ion source which provides a highly sensitive GC-MS, MS/MS capability for tandem quadrupole and time of flight MS systems. It is very easy to swap between APGC, Electrospray (for UPLC) and other ion sources without instrument venting in minutes.
APGC provides significant performance advantages over traditional GC/MS ionisation methods, giving high sensitivity and less fragmented spectra.
cobalt oxide composed with rGO as effective electrode materialjahanzaibmughal6
1) The document analyzes Co3O4@x%rGO (where x=0%, 5%, 10%, 15%) composites as electrode materials for supercapacitors.
2) Characterization of the materials showed Co3O4@15%rGO had the best performance with higher specific capacitance and energy/power densities.
3) Testing included XRD, CV, GCD, EIS and found Co3O4@15%rGO to have highly crystalline cubic structures, pseudocapacitive behavior, and longer discharge times than other compositions.
This document describes an environmental engineering laboratory course on water and wastewater characterization. The course objectives are to familiarize students with procedures to quantify quality parameters of water and sewage. It lists 14 required experiments involving sampling methods, and determination of parameters like pH, turbidity, hardness, chlorides, dissolved oxygen, and BOD/COD. The document also provides the list of required equipment, references, and procedures for individual experiments.
1. The document discusses various types of wastewater treatment processes including oxidation ditches, oxidation ponds, aerated lagoons, and septic tanks.
2. Oxidation ditches are essentially extended aeration activated sludge processes using endless ditches and rotors for aeration. Rotors are designed to impart velocities between 0.3 to 0.4 m/s.
3. Oxidation ponds, also called waste stabilization ponds, are open earthen basins that use natural means like wave action and sunlight to facilitate the aerobic and anaerobic treatment of sewage and biodegradable wastes.
Wastewater Treatment: Definition, Process Steps, Design Considerations, Plant Types (With PDF)
Written by Anup Kumar Deyin Civil,Construction,Mechanical,Piping Interface,Process
Wastewater treatment is a process to treat sewage or wastewater to remove suspended solid contaminants and convert them into an effluent that can be discharged back to the environment with acceptable impact. The plants where the wastewater treatment process takes place are popularly known as Wastewater treatment plants, Water resource recovery facilities, or Sewage Treatment Plants. Pollutants present in wastewater can negatively impact the environment and human health. So, these must be removed, broken down, or converted during the treatment process. Typical pollutants that are normally present in wastewater are:
Bacteria, viruses, and disease-causing pathogens.
helminths (intestinal worms and worm-like parasites)
Toxic Chlorine compounds and inorganic chloramines.
Metals possessing toxic effects like mercury, lead, cadmium, chromium, and arsenic.
Decaying organic matter and debris.
oils and greases.
Toxic chemicals like PCBs, PAHs, dioxins, furans, pesticides, phenols, etc.
Some pharmaceutical and personal care products
It is part of Chemical Engineering. A lot of toxic released from Chemical Industries. How to reduce that wastewater effluent. All the techniques and measurements are included in this presentation.
This document discusses various processes for separating and enriching the tritium isotope. It begins by introducing tritium isotope separation and some key concepts. It then describes several processes that have been used to enrich tritium for analytical purposes, including water electrolysis, water distillation, thermal diffusion, and permeation through membranes. The document also discusses processes that have been used to recover and enrich tritium from nuclear power plants, such as water distillation, thermal diffusion, adsorption, and chromatography. It emphasizes that effective tritium separation and control is important for both the nuclear power and potential fusion power industries.
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Test Automation with generative AI and Open AI.
UiPath integration with generative AI
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The choice of an operating system plays a pivotal role in shaping our computing experience. For decades, Microsoft's Windows has dominated the market, offering a familiar and widely adopted platform for personal and professional use. However, as technological advancements continue to push the boundaries of innovation, alternative operating systems have emerged, challenging the status quo and offering users a fresh perspective on computing.
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C:\Documents And Settings\Jbalent\My Documents\Tio061610
1. Welcome to the CLU-IN Internet Seminar Stable Isotope Analyses to Understand the Degradation of Organic Contaminants in Ground Water Sponsored by: U.S. EPA Technology Innovation and Field Services Division Delivered: June 16, 2010, 2:00 PM - 4:00 PM, EDT (18:00-20:00 GMT) Instructor: John T. Wilson, U.S. EPA, R.S. Kerr Environmental Research Center (wilson.johnt@epa.gov) Moderator: Jean Balent, U.S. EPA, Technology Innovation and Field Services Division (balent.jean@epa.gov) 1 Visit the Clean Up Information Network online at www.cluin.org
2.
3. John T. Wilson, U.S. Environmental Protection Agency Applications of Stable Isotope Analyses to Understand the Degradation of Organic Contaminants in Ground Water Part 1. Applications
4. I you have questions, or want to request a copy of the Powerpoint file, send e-mail to wilson.johnt@epa.gov.
5. Volatile organic contaminants in ground water are usually composed of carbon, hydrogen and chloride. Each of the these elements have more than one stable isotope. These stable isotopes are not radioactive. The stable isotopes differ from each other in the number of neutrons in the nucleus of the atom.
6. Element Stable Isotopes Relative Abundance Hydrogen 1 H 0.99985 2 H 0.00015 Carbon 12 C 0.9889 13 C 0.0111 Chlorine 35 Cl 0.7577 37 Cl 0.2423
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11. A recent advance: Compound specific stable isotope analyses can provide an unambiguous conservative boundary on the extent of biodegradation of MTBE in ground water.
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13. Enrichment in black dots when the rate of removal of black dots is 75% of the rate of removal of white dots.
19. What is the relationship between changes in the ratio of stable carbon isotopes and the extent of Biodegradation? Example for MTBE
20. ε is the “enrichment factor”, calculated as the slope of a linear regression of 13 C on the natural logarithm of the fraction remaining of MTBE (C/Co or F).
21.
22. -40 -30 -20 -10 0 10 20 30 40 50 0.001 0.01 0.1 1 Fraction MTBE remaining (C/Co) 13 C (per mil) anaerobic biodegradation aerobic biodegradation Natural Range in Gasoline More 13 C
28. Application for an plume of MTBE from a spill of motor fuel from an underground storage tank
29. Section 4 in A Guide for Assessing Biodegradation and Source Identification of Organic Ground Water Contaminants using Compound Specific Isotope Analysis (CSIA) EPA 600/R-08/148 | December 2008 | www.epa.gov/ada
30. Google: EPA Ada Oklahoma Select: Ground Water and Ecosystems Restoration Research Go to publications in white menu bar on left. Open: Year Select 2008
35. Tertiary Butyl Alcohol (TBA) is the first product of the biodegradation of MTBE. TBA is also a minor component of the technical grade of MTBE used in gasoline. The accumulation of TBA over time is an indication of the biodegradation of MTBE.
44. There was substantial anaerobic biodegradation of MTBE in water from many wells. There was no evidence for biodegradation of MTBE in wells at the perimeter of the plume!
48. Reproducibility of Stable Carbon Isotope Ratios over time at field scale. Well Date TBA measured ( μ g/L) MTBE measured ( μ g/L) 13 C of MTBE ( ‰) Faction MTBE remaining MW-14 5/20/03 13,000 11,000 -23.88 0.75 8/18/04 107,000 26,000 -21.58 0.62 MW-3 5/20/03 20,000 870 6.84 0.058 8/18/04 32,000 164 8.53 0.050 MW-8 5/20/03 10,000 19 18.11 0.023 8/18/04 32,000 25 37.99 0.0043
49. The average hydraulic conductivity based on slug tests of monitoring wells was 11 meters per day. The average hydraulic gradient was 0.0023 meter/meter based on thirteen rounds of water table elevations. Assuming an effective porosity of 0.25, the average seepage velocity is 37 meters per year.
50. F is the fraction of MTBE remaining d is the distance between the wells v is the ground water seepage velocity
51. Well Date Fraction MTBE Remaining (C/C o ) Distance from MW-14 (meters) Projected Rate Biodegradation with Distance (per meter) MW-3 5/20/03 0.058 9.6 0.30 MW-3 8/18/04 0.050 9.6 0.31 MW-8 5/20/03 0.023 11.7 0.32 MW-8 8/18/04 0.0043 11.7 0.46
52. Well Date Fraction MTBE Remaining (C/C o ) Distance from MW-14 (meters) Projected Rate Biodegradation with Time (per year) MW-3 5/20/03 0.058 9.6 10.9 MW-3 8/18/04 0.050 9.6 11.5 MW-8 5/20/03 0.023 11.7 11.9 MW-8 8/18/04 0.0043 11.7 17.1
54. Well Date TBA measured ( μ g/L) MTBE measured ( μ g/L) 13 C of MTBE ( ‰) Faction MTBE remaining MW-6 5/20/03 3,600 47 9.83 0.045 8/18/04 19,200 490 -1.58 0.116
55. Well Date Fraction MTBE Remaining (C/C o ) Distance from MW-14 (meters) Projected Rate Biodegradation with Distance (per meter) MW-6 5/20/03 0.045 31.1 0.10 MW-6 8/18/04 0.116 31.1 0.069
56. Well Date Fraction MTBE Remaining (C/C o ) Distance from MW-14 (meters) Projected Rate Biodegradation with Time (per year) MW-6 5/20/03 0.045 31.1 3.7 MW-6 8/18/04 0.116 31.1 2.6
59. *The concentration MTBE was below the limit for the accurate determination of δ 13 C; the precision of the estimate of δ 13 C was ±3 ‰ rather than ± 0.1 ‰. Well Date TBA measured ( μ g/L) MTBE measured ( μ g/L) 13 C of MTBE ( ‰) Faction MTBE remaining MW-14 5/20/03 13,000 11,000 -23.88 0.75 8/18/04 107,000 26,000 -21.58 0.62 MW-7 8/18/04 1,220 106 -27.33 0.994 MW-11 5/20/03 <10 1 -31.5* 1.41 8/18/04 135 318 -28.92 1.14
60. Well Date Fraction MTBE Remaining (C/C o ) Distance from MW-14 (meters) Projected Rate Biodegradation with Distance (per meter) MW-7 8/18/04 0.994 23.0 0.00025 MW11 5/20/03 1.0 44.1 0 MW11 8/18/04 1.0 44.1 0
61. Well Date Fraction MTBE Remaining (C/C o ) Distance from MW-14 (meters) Projected Rate Biodegradation with Time (per year) MW-7 8/18/04 0.994 23.0 0.0093 MW11 5/20/03 1.0 44.1 0 MW11 8/18/04 1.0 44.1 0
81. The hypothetical receptor at 1000 feet from the source was intentionally chosen to illustrate the dominant role of biodegradation on the attenuation of concentrations of contaminants in ground water.
82. Given the uncertainty in modeling, there is substantial possibility that MTBE will impact the hypothetical receptor at unacceptable concentrations. The exposure assessment for most real receptors will be much less ambiguous.
83.
84. Note that the real attenuation in concentrations were substantially greater than would be expected from the prediction of C/Co based on the analysis of stable carbon isotopes.
85. With Source at 26 mg/L and Biodegradation = 10 per year Field scale reductions in concentration are greater than predicted from C/Co estimated from CSIA Real Predicted
90. Proximity to NAPL or other source of new contamination to ground water allows fresh (unfractionated) material to dissolve into water to replace the material that was removed by degradation. This dilutes the fractionated material, and reduces the overall value of 13 C . CSIR will underestimate the true extent of degradation.
92. Assume all the TBA formed from degradation of MTBE, and that none of the TBA was further degraded.
93. Effect of Proximity to NAPL on Prediction of Fraction Remaining from 13 C Well Date TBA ( μ g/L) MTBE ( μ g/L) MTBE C/Co 13 C of MTBE ( ‰) Predicted MTBE C/C0 MW-14 5/20/03 13,000 11,000 0.42 -23.88 0.75 8/18/04 107,000 26,000 0.17 -21.58 0.62 MW-3 5/20/03 20,000 870 0.035 6.84 0.058 8/18/04 32,000 164 0.0043 8.53 0.050 MW-8 5/20/03 10,000 19 0.0016 18.11 0.023 8/18/04 32,000 25 0.00065 37.99 0.0043
94. Variations in expression of carbon isotope fractionation of chlorinated ethenes during biologically enhanced PCE dissolution close to a source zone P.L. Morrill, B.E. Sleep, D.J. Seepersad, M.L. McMaster, E.D. Hood, C. LeBron, D.W. Major, E.A. Edwards and B. Sherwood Lollar Journal of Contaminant Hydrology, Volume 110, Issues 1-2, 3 November 2009, Pages 60-71
95. Despite extensive degradation of PCE that could be recognized by the accumulation of products, isotopic fractionation of PCE was not detectable above the uncertainty in the measurement in ground water in contact with NAPL PCE.
96. These two interactions have important consequences for design of a sampling strategy for CSIA. Samples should be evenly balanced between high concentrations, intermediate concentrations, and low concentrations. Putting an heavy emphasis on wells with low concentrations of organic contaminants may seriously underestimate the true contribution of degradation processes at a site.
97. These two interactions have important consequences for design of a sampling strategy for CSIA. The absence of fractionation in particular wells, particularly in wells with low concentrations of contaminant, should not be taken as evidence for there is no degradation in the plume.
98. John T. Wilson, U.S. Environmental Protection Agency Applications of Stable Isotope Analyses to Understand the Degradation of Organic Contaminants in Ground Water Part 2. Data Quality Issues
99. Documenting Quality for CSIR analyses I you have questions, or want to request a copy of the Powerpoint file, send e-mail to wilson.johnt@epa.gov.
100. A Guide for Assessing Biodegradation and Source Identification of Organic Ground Water Contaminants using Compound Specific Isotope Analysis (CSIA) EPA 600/R-08/148 | December 2008 | www.epa.gov/ada
101. Recommendations for sample collection, sample preservation, and sample analysis. Recommendations on QA/QC issues Details on calculations. Catalogue of values for δ 13 C, δ 2 H, and ε .
102.
103. The following comments apply to analysis of stable isotopes of carbon. They can be typically extrapolated as needed to analysis of stable isotopes of hydrogen and chlorine.
104. Standards for carbon isotope analyses The isotope ratio mass spectrometer measures the isotope ratios of carbon dioxide produced from the combustion of the compound of interest. There are three standards: The International Atomic Energy Agency standard (primary standard) The laboratory’s CO 2 working standard (secondary standard) The laboratory’s compound specific working standard for a particular VOA.
105. The International Atomic Energy Agency Standard Samples provided by the IAEA that have a known ratio of carbon stable isotopes. In the United States the standard is provided by the National Bureau of Standards. The IAEA Standard allows comparability of data from one lab to the other. Used for primary calibration of instruments.
106. The laboratory’s CO 2 working standard Calibrated against the IAEA international standard. Used for tuning the instrument and day to day calibration checks of the instrument. Provides the value against which all target peaks in a given run are standardized.
107. The laboratory’s compound specific working standard A sample of the compound being analyzed that has a known value for δ 13 C. The standard is analyzed periodically in a sample set to document that the instrument is properly calibrated. The compound specific working standard is also used to document the effective detection limit as discussed later.
108. At a minimum, the CO 2 working standard is analyzed twice at the beginning of each sample run. The automatic software routine uses one of these CO 2 peaks as the reference to calculate isotope ratios for the other peaks, including those of the second (or multiple) CO 2 peaks. At least every fifth sample should be a sample replicate. At least every tenth sample should be the compound specific working standard.
109. Require the vendor to provide the true value of δ 13 C for each compound working standard. Ask the vendor to report the values determined for their compound specific working standard during analysis of the samples. The scope of work or the QAPP should specify an acceptable range of determined values from the true value for the compound working standard. The determined values of the compound specific working standard should fall within the acceptable range from the true value.
110. How to determine the acceptable range of values to specify in the scope of work or the QAPP? Ask the vendors to provide the acceptable range of values in their bid or quote. Review and determine if the range in acceptable values meets the requirements of your project based on the comparisons you are going to make.
112. Select a conservative value for the enrichment factor from the literature (a value with a low absolute value), and solve the equation for the fraction remaining ( F ), based on the difference in δ 13 C that you can resolve based on the acceptable range of the compound specific working standard proposed by the vendor . As a rule of thumb, you can resolve samples with good confidence when they differ by twice the acceptable range.
113. Values of ε are tabulated in Table 8.1 of the U.S. EPA Guide. Suppose you were interested anaerobic biodegradation of TCE. The value of ε with the lowest absolute value is -2.56‰. If the quoted acceptable range was 0.5‰, you can distinguish samples that differ by 1.0‰. The extent of degradation that can be detected is-
114. How to establish the effective detection limit for determination of δ 13 C for a particular compound? Customers tend to think of the detection limit as a concentration of the chemical being analyzed. The concentration is related to the amplitude of the mass 44 peak, expressed as a voltage, or the area of the peak, expressed as volt-seconds.
115. The next slide is Figure 2.5 in A Guide for Assessing Biodegradation and Source Identification of Organic Ground Water Contaminants using Compound Specific Isotope Analysis (CSIA). The following is the figure legend. Example of the evaluation of method detection limits (MDLs) in CSIA. The squares represent the 13 C values in ‰ and the diamonds show the amplitude of mass 44 in mV. Error bars indicate the standard deviation of triplicate measurements. The horizontal broken line represents the iteratively calculated mean value after the methods of Jochmann et al. (2006) and Sherwood Lollar et al. (2007). The solid lines around the mean value represent the standard deviation on the mean of triplicate measurements. Figure modified after Jochmann et al. (2006).
116. -23.0 -24.0 -25.0 -26.0 -27.0 -28.0 -29.0 -30.0 -31.0 8.0 0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 10000 8000 6000 4000 2000 0 Amplitude of mass 44 (mV) Concentration in water ( g/L) 13 C ‰ Method Detection Limit (0.2 g/L) 13 C Amplitude of mass 44 Benzene
117. Citations: Jochmann, et al. A new approach to determine method detection limits for compound specific isotope analysis of volatile organic carbons. Rapid Communications in Mass Spectrometry 20: 3639-3648 (2006). Sherwood Lollar,et al. An approach for assessing total instrumental uncertainty in compound-specific carbon isotope analysis: implications for environmental remediation studies. Analytical Chemistry 79: 3469-3475 (2007).
118. Jochmann et al. 2006 suggested an appropriate method detection limit (MDL) could be defined as the signal size below which the standard deviation of the mean exceeds 0.5‰ and the δ 13 C values are outside the 0.5‰ interval around the running mean. Sherwood Lollar et al. 2007 suggest that a more conservative approach might be to define the method detection limit as the point at which the variance around the mean significantly increases (typically at signal size < 0.5 V).
119. 0 1.0 2.0 3.0 Concentration in water ( g/L) Method Detection Limit (0.2 g/L) Benzene -23.0 -24.0 -25.0 -26.0 -27.0 -28.0 -29.0 -30.0 -31.0 13 C ‰ mean ± standard deviation of triplicate analyses
120. One vendor specifies a practical quantitation limit that is round number that is slightly larger than the method detection limit (MDL). This PQL allows for minor variations in the sensitivity of the instrument. If the area of the mass 44 peak is less than the MDL, the vendor does not report an isotope ratio and flags the analysis as “U”. If the peak area is between the MDL and PQL, the vendor reports the peak area and the isotope ratio and flags the isotope ratio with a “J”.
121. Provide guidance on QA in the scope of work or QA Project Plan. Determine the difference in δ 13 C or δ 2 H that you need to resolve. If you really don’t know what difference you need to resolve, as a default, require that the standard deviation of the samples of triplicate samples of the compound working standard be equal to or less than +/-0.5 ‰ for δ 13 C and equal to or less than +/-5 ‰ for δ 2 H. At this level of uncertainty, you can resolve a difference between samples when the difference in δ 13 C >1 ‰ or the difference in δ 2 H >15‰.
122. Detection limits should always be determined using the same chromatographic column and working conditions as the samples. The compound working standards should be subjected to the entire analytical procedure including any extraction and concentration steps. The compound working standards should be spiked into water, then extracted and prepared for gas chromatography following the same procedures as the samples.
123. Based on the requirements of your project, identify the lowest concentration of the VOA that you are interested in analyzing for isotope ratios. The method detection limit, or practical quantitation limit, should correspond to a concentration that is lower than this lowest concentration you have identified for the project. Ask the vendor to provide the MDLs or PQLs in their bid. Compare their capability to your requirement.
124. Require the vendor to report the values of replicate analyses (n=3) of the compound specific working standard at this lowest concentration. As an estimate of precision in the determination of isotope ratio for the compound specific standard at this lowest concentration, calculate the mean and standard deviation on the samples.
125. The mean should not differ from the true value by more than the acceptable range. The sample standard deviation should not be greater than the acceptable range. As an alternative, one vendor prefers to calculate the sample standard deviation of the range of the samples as the best indication of system performance.
126. -23.0 -24.0 -25.0 -26.0 -27.0 -28.0 -29.0 -30.0 -31.0 8.0 0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 10000 8000 6000 4000 2000 0 Amplitude of mass 44 (mV) Concentration in water ( g/L) 13 C ‰ Method Detection Limit (0.2 g/L) 13 C Amplitude of mass 44 Benzene
127. Notice that the amplitude of the mass 44 ion is roughly proportional to concentration of compound of interest. There will be an amplitude of the mass 44 ions that is associated with the lowest concentration of compound that you are interested in.
128. An Alternative: After you see the data, you may be very interested in certain samples that had low concentrations of the VOA. Those samples may have experienced the most biodegradation. Require the vendor to flag δ 13 C values that were performed on any samples where the amplitude of the mass 44 ion corresponded to concentrations that were below that lowest concentration of compound you identified to the vendor.
129. An Alternative: Require the vendor to report the values of δ 13 C of replicate analyses (n=3) of the compound specific working standard at a concentration that corresponds to the amplitude of the mass 44 ion in the flagged samples. A replicate of the original sample should be included in the same sample run as the replicates of the diluted compound specific working standard.
130. An Alternative: This is a very open-ended approach. It is impossible to determine before hand how much labor would be involved. Expect to pay the vendor for the additional work necessary to determine the precision of the isotope ratio analysis on the flagged samples.
131. Detection limits should always be determined using the same chromatographic column and working conditions (including split ratios) as the samples. The compound working standards should be subjected to the entire analytical procedure. The compound working standards should be spiked into water, then extracted and prepared for gas chromatography following the same procedures as the samples.
132. An isotope ratio mass spectrometer can analyze samples over a fairly narrow range concentrations. All samples should stay within the acceptable range and above the established threshold limit. If a sample falls outside the acceptable range, the concentrations of the analytes should be adjusted, if possible, to bring the sample within the acceptable range, and the sample analyzed a second time. This is one reason the vendors want so many replicate water samples. There may be several repeat analyses.
133. Figure 2.1 of U.S. EPA Guide. GC IRMS requires clean separation of peaks of individual compounds.
134. In most plumes of chlorinated solvents, there are usually few VOA compounds in the water, and peaks of individual compound are clearly separated from each other. In plumes that originate from spills of petroleum, conventional GC columns may not separate peaks for the compounds of interest from co-eluting compounds.
135. In many states, the concentrations of MTBE and benzene in ground water at UST sites are determined by Gas Chromatography with a Mass Spectrometer Detector (EPA Method 8260) instead of Gas Chromatography with a Flame Ionization Detector (EPA Method 8015). The more expensive method (8260) is required because the GC column often can not separate the MTBE or benzene from other components of the fuel.
136. For some compounds baseline resolution is impossible: 1. isomers of chlorobenzene 2. higher molecular hydrocarbons in the gasoline or diesel range that elute on top of a rising baseline. 3. MTBE and 1,1-dichloroethane co-elute on some columns.
137. Determination of concentrations using GC Mass Spectrometry is fairly forgiving of overlapping peaks in the chromatograph. The ions characteristic to a specific compound can be used to recognize and quantify the compound of interest. The Flame Ionization Detector works by burning the compounds. It can not distinguish between compounds in overlapping peaks. Like a Flame Ionization Detector, the Isotope Ratio Mass Spectrometer is not forgiving. All of the compounds are oxidized to CO 2 , and the mass ratio of the CO 2 that is derived from each compound is determined separately.
138. It is impossible to determine beforehand whether there will be overlap of peaks in the chromatograph from a particular sample. As a result, it is difficult to protect against this source of error in a scope of work or QAPP. However, there are things that can be done to recognize overlap of peaks and alternatives to improve the separation of peaks.
139. One way to detect problems with co-elution is to examine the chromatogram for shoulders on the front or back of each target peak, or more generally, any differences in peak shape as compared to the standard.
140. You might task the vendor to provide in the report one or a few of the most complex chromatographs. There are the chromatographs where there is a greater chance that peaks of other compounds will overlap the peaks for the compounds of interest. You might require that “analyses only be performed when peaks for the compound of interest are clearly resolved from co-eluting peaks.” However, without some quantitative description of “clearly resolved”, the requirement is ambiguous.
141. Often, the Project Plan will require data on concentrations was well as isotopic ratios. To minimize operator time on the IRMS, some vendors require that an analyses of concentrations of VOCs to be provided by the client. Frequently, the samples will be analyzed for concentrations using Method 8260 or equivalent.
142. If the same chromatographic column and conditions are being used for Method 8260 and the CSIA, examine the full-scan mass spectra of the peak compared to the mass spectrum of a standard, and look for the presence of mass fragments in the sample spectrum that are unaccounted for in the spectrum of the standard. Look at the non-background-subtracted spectra, to avoid subtracting out the contribution from a compound in the shoulder of the main peak. Anything that has an abundance greater than 10% of the base peak is suspect, and requires further consideration and evaluation.
143. Part of Figure 2.1 of U.S. EPA Guide. The ratio of mass 45 to mass 44 ( 13 C-CO 2 to 12 C-CO 2 ) is called the ratio trace of the peak. If there are co-eluting peaks, the shape of the trace will depart from a trace of the pure compound.
144. The error caused by co-eluting peaks will be the greatest when concentrations of the VOA are low, and the difference in isotopic ratios between samples is small. When these circumstances apply, you might require the vendor to compare the ratio trace for each analysis against the trace of the compound specific standard. For particularly crucial analyses, you might require the vendor to provide copies of the ratio traces in the report.
145. Other factors can influence the shape of the ion trace, including the extent of isotopic fractionation of the sample compared to the compound specific standard. Interpreting the trace is best left to an analytical chemist that is familiar with the instrument and the analytical protocol that was used to acquire the data.
146. As mentioned previously, the amplitude of area of the ion 44 peak is roughly proportional to the concentration of the VOA. Linear extrapolation can provide an estimate of the concentration of the VOA from the amplitude or area of the ion 44 peak. If there is a concern with the symmetry of the ion ratio trace, you may task the analyst to compare the estimate of concentration from the IRMS to the concentration reported using GS/MS such as Method 8260. Extreme differences between the two estimates may indicate problems with co-elution or other matrix effects.
147. To perform CSIR of EDB in gasoline spills, Paul Philp’s lab at the University of Oklahoma had to use two dimensional chromatography to get good peak separation. In this case, “two dimensional” means they used two different GC columns in sequence to achieve adequate separation. Natural Attenuation of the Lead Scavengers 1,2-Dibromoethane (EDB) and 1,2-Dichloroethane (1,2-DCA) at Motor Fuel Release Sites and Implications for Risk Management . EPA 600/R-08/107 | September 2008 | www.epa.gov/ada.
148. Analysis δ 13 C or δ 2 H of aromatic hydrocarbons or chlorinated VOCs should be performed on a conventional water sample in a 40 ml VOA vial preserved with HCl to pH <2. Preserve samples of ethers such as MTBE with trisodium phosphate to pH>10.5. As of this date, appropriate preservation of chlorinated VOCs for δ 37 Cl has not been specifically evaluated but similar approaches to the above are likely to be required. Require the vendor to specify the appropriate technique to preserve samples.
149. Under some circumstances, analyses for CSIA must wait for analyses on concentrations of VOAs in the samples. The clock is running on holding time while the vendor for the CSIA is waiting for the concentration data. Data in the EPA Guide (Section 3.4) documents the capacity of hydrochloric acid and trisodium phosphate (as appropriate) to preserve samples for 28 days.
150. It is best to collect samples for analysis of concentrations and for CSIA at the same time. The analyses can be performed on the same sample set, and the results are directly comparable. Avoid collecting samples for concentrations and CSIA on different days.
151. Vendors may require as many as nine replicate samples from each well. The vendor should specify the number of replicates in the bid. You really can’t sample the same ground water twice. The cost of the vials is a tiny part of the cost of sampling. Collect more samples than you think you will need, and discard them if they are not needed.
153. From Section 5 of U.S. EPA Guide Preliminary Survey to Justify Comprehensive Study 4 to 6 Wells Comprehensive Survey MNA on one plume 13 to 24 wells Up gradient of source 1 to 2 wells Source zone 3 to 5 wells Center flow line 4 to 5 wells Boundary of plume 4 to 8 wells Vertical extent 1 to 4 wells Plume stability, resample one to three years later 6 to 15 wells
154. Approximate Cost is $200 to $400 for one sample for one compound for one isotope ratio. Additional compounds determined for the same isotope ratio can cost $50 to $100 per sample. Circumstances can reduce this cost. Don’t compare the costs of CSIA to the cost to analyze samples for concentrations. They are different analyzes conducted for different purposes.
155.
156. At many hazardous waste sites, we are content to collect data on concentrations four times a year for five or ten years, and then try to make inferences about biodegradation that are not satisfying or compelling. Twenty to forty analyses using Method 8260 don’t answer the question about biodegradation because they provide the wrong information. When conditions are favorable, one CSIA analysis on water from one well can document the extent of biodegradation. CSIA analyses on water from two wells can provide an estimate of the rate of degradation.
157. Patrick McLoughlin [email_address] Microseeps University of Pittsburgh Applied Research Center 220 William Pitt Way, Pittsburgh, PA 15238 412 826 5245 fax 3433 Commercial Source of Analytical Services
158. Patrick McLoughlin [email_address] Microseeps University of Pittsburgh Applied Research Center 220 William Pitt Way, Pittsburgh, PA 15238 412 826 5245 fax 3433 Commercial Source of Analytical Services
159. Paul Philp Department of Geology and Geophysics 100 East Boyd Avenue University of Oklahoma Norman, Oklahoma 73019 405 325 4469 fax (405)-325-3140 [email_address] Commercial Source of Analytical Services
160. Zymax Forensics Yi Wang Director, Zymax Forensics Isotope 600 South Andreasen Drive Suite B, Escondido, California 92029 [email_address] Commercial Source of Analytical Services
161. Barbara Sherwood Lollar Department of Geology University of Toronto 22 Russell Street, Toronto, Ontario M5S 3B1 Phone: (416) 978-0770 Fax: (416) 978-3938 E-mail: [email_address] Commercial Source of Analytical Services
162.
Editor's Notes
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