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- Groundwater Sampling
- Type of Pump and Pump Operation
- Varied results between different brands of Sampling kits
- Which is better Teflon or Poly bladders
- How does limitation affect velocity at which water enters the sampling pump
- Can you use a peristaltic pump for low flow voc sampling
- What is the recommended sampling method for small diameter wells
- Is there a preference in low flow sampling of using peristaltic pumps or bladder pumps?
- Can other pumps be used other than bladder pumps and do submersible centrifugal pumps affect DO?
- Does QED manufacture a portable bladder pump for use in half inch wells?
- Are 12 volt submersible pumps acceptable for low flow sampling?
- Is using polypropylene tubing less effective than using Teflon.
- Is sorption a problem using polyethylene tubing for low flow sampling at gasoline hydrocarbon sites?
- Is there a way to protect a low-flow system when pumps are being moved between individual wells?
- What type of pump is recommended for collecting low-flow samples from depths greater than 30 feet?
- What types of low-flow pumps are best when testing for VOCs?
- How do you deal with VLC volatilization in low water volume wells as a result of temperature increase caused by a pump heating up in the water?
- What are the differences in VLC concentrations observed between low-flow and passive diffusion devices?
- What do you do with a water table that’s greater than 30 feet but you can’t use a peristaltic pump?
- When using 4-inch wells does the well width have an effect on low-flow sampling?
- Do bladder pumps need to be replaced, how often, and how can you tell?
- Is there a company that makes a bladder pump that will operate in a ½-inch well?
- Can you tell me the price difference between electric and pneumatic pumps?
- Do you always see an increase in gas flow after dewatering?
- Is there a depth limitation for low-flow sampling using a bladder pump? If so, what is that depth?
- If you are currently using a generator-powered bore pump where purge is controlled by frequency and you cannot slow the rate down to .5 or 1 L/min as recommended, what suggestions do you have to improve the quality of those results?
- Is a peristaltic pump suitable for low-flow sampling?
- Do you consider a snap sampler to be a suitable low-purge sampling device?
- Are there any studies showing that bladder pumps provide better quality VOC data than peristaltic pumps?
- Pump Position
- What is the depth limitation for low flow bladder pump sampling
- Does placement of a low flow pump within the well screen matter
- When using a portable pump that cannot get 5 feet from the bottom due to length, how critical is pum
- For low flow purging if the groundwater level is below the well screen should the pump still be plac
- If pump intake placement doesn't matter why would the Florida DEP mandate that his pump intake be pl
- The study that compared DCE and TCE between no-purge and low-flow, were the samples different?
- When using a peristaltic pump where is the ideal location for the tubing inlet?
- What are the capabilities of bladder pumps as far as depth?
- How vital is it to accurately know the construction details of the formation in terms of pump inlet placement?
- What different approaches are required for open bedrock wells?
- Purging Flow Rate
- Can a pumping rate be too low for purging
- Can a multi-parameter probe flow cell be used to show the well is stable before sampling instead of
- ORP seemingly dives at times when the other parameters are stable?
- What would be the proper action to take if purge volume is numerically sufficient?
- How long do you purge a well if one of the parameters will not stabilize
- What is the minimum amount of volume/time to purge a well while using the low flow method?
- In low-flow sampling, is it still important to collect samples for volatile analysis first?
- With the no-purge method, at what rate would you recommend collecting the samples if there is plenty of volume in the well?
- For wells with no recovery and no stabilization that you need to purge and pump and then sample, at what rate do you sample?
- How often do you take on-site parameter readings?
- Do you have suggestions for keeping water flowing at low-flow rates when the temperatures are -20 to -30 degrees.
- PurgeStabilization Methods and Criteria
- Are there documents for dissolved oxygen stabilization range
- Why isn't DO percentage appropriate for stabilization criteria aside from the fact that you can't do
- What purge method would you recommend for regional studies utilizing private domestic wells?
- Does the flow-through-cell use a Photo DO method?
- When pH temperature and conductivity are being documented, how important is DO in determining accura
- The parameters are stable but is below the recommended purge rate. Will a sample be representative?
- If an aquifer is under confined conditions do you need field parameter
- Would it be quicker and equally effective to use normal purging and filter the samples if you're onl
- How do you determine when the readings are stabilized?
- What is the most critical parameter to stabilize before sampling?
- Should you use historical purge volumes along with parameter stabilization with low-flow purging?
- How can you do low-flow sampling without parameter stabilization?
- What if your wells are low-yield and you cannot get the water level to stabilize even at a very low flow rate, or you have a 5-foot drawdown at a well with a 10-foot column of water, can low-flow sampling still be used?
- If you determine that low-flow sampling will not work in a well, can sampling still occur the same day?
- Why does low-flow stabilization occurs for some parameters within 15 minutes but take other as long as 45 minutes to stabilize?
- What do you think about redox parameters being used as an indicator for groundwater stabilization?
- Is there any way of estimating the flow through a screen in situ, such as a propeller, as a test to see whether the water level can be maintained?
- What is the difference between “purge until indicator parameters are stable” and low-flow purging and sampling?
- Are the EPA standards for parameter stabilization supported by other research?
- How should purging parameter limits be established?
- Sampling
- What parameters need to be measures for a representative sample
- Is there documentation for low-flow sampling Standard Operating Procedure
- Is there any benefit to reduce the rate of the sample
- Is low flow sampling applicable for fractured rock aquifer?
- How important is it to eliminate the bubbles within sampling containers, what effect does this have
- When it comes to flow rate on a portable pump controller does any controller give you a specific amo
- Have you noticed any false positives and/or negative in VOC sampling while utilizing polyethylene bl
- Vertical flow conditions are an important issue for fractured rock wells?
- Is it okay to sample when the indicator parameters have stabilized but the water level is still drop
- Is this the correct sequence of bottle-filling, VOC, SVOC metals then filtered?
- How important is it to develop a well prior to low-flow sampling?
- What do you think about taking water from the casing without purging, low-flow or passive sampling?
- Is it feasible to sample hydrocarbon compounds in the dissolved phase?
- Is there a ranking of analytes from minimum to maximum difference when sampled?
- Should samples be collected immediately after bailing three to five casing volumes?
- What is the minimum tube size for low flow sampling?
- Are there any studies showing how low-flow works in open bedrock wells versus screen wells? It seems the same situation would apply: water will enter from the water producing zones. Would this hold true, or might there be a difference for open bore versus
- Can bladder pumps become contaminated in wells and then influence sample concentrations?
- How bad is it if you dewater the well with a low-flow system?
- Does low-flow sampling get representative samples of petroleum NAPLs in an inlet that is 10 meters below the water level?
- If a low-flow pump retrieves a representative sample from the entire screen zone, how can you collect a sample from a discrete interval?
- What is your opinion of passive sampling?
- How can a representative sample be obtained from a highly stratified water table?
- Do you need to remove any of the pumps that may be down well after you are done sampling?
- When would low-flow not be suitable?
- What is the sample protocol for portable low-flow systems?
- How do you sample from deep wells with increased pressure?
- Drawdown
- At what point does drawdown disrupt equilibrium and impact sample results
- What are standard limits of drawdown for low flow sampling
- What is the maximum drawdown allowed when sampling?
- Measuring drawdown while you are pumping
- Problems with parameters and drawdown stabilization wells
- Is it the amount of drawdown that determines the mixing
- What is considered unacceptable drawdown with low-flow purging?
- What are good parameters and corresponding stabilization criteria for drawdown?
- Do you have any suggestions for wells that reach drawdown stabilization between 10 and 50 mL per minute?
- In a low-flow dedicated system where drawdown cannot be stabilized due to very low hydraulic conductivity what is the recommended protocol?
- If the .1-meter drawdown specification from the EPA is not really valid should any rule of thumb be used for the amount of acceptable drawdown or does the science say that you only need to pay attention to drawdown stabilization?
- Is there an upper limit for purging and sampling as long as drawdown is not affected?
- Are there any drawbacks to using flow rates of less than 100 mL per minute if they are required to limit drawdown?
- Low Recovery Wells
- In very low-yield wells where pumps are installed in silty formation, will low flow save time?
- Are there documents reguarding sampling of slow recarge wells
- Is there any value of evacuating a well after a low flow sample has been collected
- What purging and sampling procedure would you recommend for low yielding wells
- What procedure would you recommend for wells with limited volumes
- Which purging sampling method for low-yielding wells with a limited volume screened interval?
- How does low flow work with small diameter wells, one-inch wells install using a DPT break?
- If the water level keeps dropping at 100 ml/minute, what do you do?
- In very low-yield wells when several samples need to be taken, what is the best method?
- How do you deal with a low-yield well that will not show a stabilized water level during low-flow purging?
- In low-yield wells is it advisable to use low-flow sampling?
- What would you recommend for low-flow wells of less than 30 mL per minute.
- Can you explain the basic criteria for low-flow sampling?
- Regulatory Issues
- EPA documents- USEPA 1996, Puls and Barcelona; and USEPA 2002 Yeskis and Zavala.
- Scientific support for reversals in sample collection order
- How do you convince regulators that sampling methods are appropriate
- What are the main objections of regulators against the low flow sampling system
- Do you need to ignore historical data during statistical analysis
- How does 3 cm per second limitation affect water velocity entering pump
- Are there any states that do not permit low flow sampling?
- Do low-flow bladder pumps have an adverse effect on bacteria results?
- Why would you want to purge a well with a pump that cannot be used to sample causing you to use a bailer after purging with the pump?
- Miscellaneous
- Why run 100 mL through filter before sampling?
- Field filtering PAH samples
- Is low-flow sampling good for a pump and treat system
- How Do I Calibrate My MP20
- Do catalatic converters remove VOCs
- What is the minimum ambient flow for using no purge sampling
- Do you have any helpful hints for sampling in freezing conditions
- If no-purge sampling is acceptable, then why is well purging necessary?
- What method would you recommend for treated sewage effluent injection to monitoring wells?
- Can you suggest changes to traditional monitoring well construction for a low-flow sampling regimen?
- What constituent was the study measuring based concerning sample collection methods that compared th
- If we do have a short well screen, do we see a significant difference between low flow and no-purge
- Can large machinery or movement of nearby wells cause release of buildups in nearby soil?
- On what basis do you say that low-flow sampling takes less time than traditional methods?
- Do low-flow systems handle low temperatures?
- What is the difference between using a 5-micron filter rather than a 0.45-micron filter?
- Has low-flow been applied to areas where the water levels are influenced by tidal fluctuations?
- For a project that used a traditional sampling method to develop a baseline, but then later needed to switch to low-flow sampling, how do you reconcile the difference between the two methodologies?
- If the conductivity in the well is greater than in the formation, could you expect that the water would be gone from within the well above the pump first?
- In a portable pumping system when lowering the pump and drop tubes into the well, won’t water be forced out of the well as the volume of the pump and tubes raises the head into well? How do you deal with this occurring?
- Does the water quality meter's data logger have the capacity to incorporate the water levels when the water level meter is, also plugged in?
- Type of Pump and Pump Operation
- Remediation and Landfill Pumping
- Liquid Landfill Control
- Do you always see an increase in gas flow after dewatering and what factors affect it?
- Information on the cause of forming leachate and geysers.
- If you are using a gravity under drainage leachate collection system are you likely to need addition
- The bioreactor landfill seems to have advantages in a landfill being too wet.
- Could leachate recirculation promote landslides in landfill?
- Is it bad to dewater wells at a closed site?
- How do you manage liquid levels in a gas header?
- Could pumping out liquid in wells result in increased well temperatures, or result in a reaction that could cause raised temperatures in the area of the well?
- How is leachate typically re-circulated in a leachate recirculation system; specifically how is it reintroduced into the landfill?
- Are there potential issues with introducing liquid into the landfill, such as it causing a reduction in gas flow in the wells?
- Can a bioreactor landfill become too wet?
- Are there benefits to re-circulating hazardous waste landfill leachate?
- Pump Type Selection
- Pump Removal and Cleaning
- Liquid Landfill Control
- Landfill Products
- Product Recovery
- Air Strippers - VOC Removal
- Principles of Operation
- Why would you have both water and air counter current?
- Would cascading water flow in the treatment plant be considered an air stripping type of treatment? How efficient could it be?
- How does a sealed box in a sliding tray stripper allow air water mass transfer - is there an air circulation system?
- What do you use for clean air?
- General Air Stripper Application Issues
- How important is it to have an inside dilution port to introduce warmer, inside air during winter mo
- Could you comment on stripping water contaminated with ammonia?
- What do you do with the VOCs that are stripped out?
- Can this technology be incorporated into potable water supplies?
- Can you pretreat influent to remove surfactants?
- Why do you pressurize the stripper instead of using a vacuum?
- Are chlorinated compounds also considered volatile compounds? The have higher specific gravities than typical volatiles – does the turbulence in an air stripper make them more volatile?
- In a system that uses oxidation in advance of the air stripper – the air stripper is in place to address what is left over after the advanced oxidation – do you know if residual ozone or hydrogen peroxide may compete with stripping of the TCA?
- Can the E-Z Tray be used in an induced draft situation?
- At what point in the process is an air stripper installed for a surface water treatment plant?
- Where do the stripped VOCs go?
- Are there any concerns with air quality at the air discharge point?
- VOC Removal Performance
- Can adding a biocide affect the air stripper system performance?
- How do you improve removal efficiencies for MTBE?
- Is a phosphoric-based sequestering agent harmful to stripper performance?
- Can warmer air increase stripper performance?
- Is there a known effect of less than 10micron suspended solids?
- Could you comment on stripping water contaminated with ammonia?
- Can you pretreat influent to remove surfactants?
- Does QED have a way of removing VOCs from a gas stream? For example: 85% moisture at approximately 190 degree Fahrenheit and 50% oxygen.
- No, there will be no competition there.
- Have you compared the performance of air strippers to a diffused aerator at sites with high fouling conditions?
- Can the E-Z Tray obtain NSF 61 certification for drinking water applications?
- What materials do you recommend for use in landfill gas wells?
- What is the present approximate treatment cost per 1,000 gallons of potable water produced?
- Pilot Systems
- Tray Fouling, Cleaning and Prevention
- Can fouling not occur within the tray holes?
- How do you remove iron/hardness scaling/fouling?
- How easy is it to pull trays?
- At what levels of calcium, magnesium and iron would you recommend pre-treatment to prevent scaling?
- What is the highest concentration of dissolved iron that you can have in successful tray stripper applications?
- In a drinking water system with 27 grains of hardness, and adding a phosphate, how will this affect the trace?
- If you are using an extraction well that is being injected with hydrogen peroxide and iron sulfate can that cause problems with the materials of the E-Z Tray Air Stripper beyond iron fouling?
- What are the typical problems encountered with the system O&M for sliding tray strippers?
- Air Stripper Materials and Features
- Troubleshooting
- Miscellaneous
- How important is it to have an inside dilution port to introduce warmer, inside air during winter mo
- What is a P & ID?
- What do you do with the VOCs that are stripped out?
- What is the price differential between the open front and the stacked tray stripper?
- Can the QED tray stripper be used with products like pro-control or pro-view to allow the system operation to be monitored and modified remotely?
- How are the E-Z Tray units decommissioned? Can they be moved to other sites?
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