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Discussion, Deliberation, and Recommendations Sessions

The following is a summary of the discussions that took place after the formal presentations on Thursday, April 15 and Friday April 16, 2004 based on notes compiled by Cat Shrier of Golder and Associates and review of tape recordings of the actual discussions.

Thursday April 15 - Discussion Topics

Friday April 16 - Discussion Topics

Thursday April 15

1) How many monitor wells are needed for an ASR well?
Many opinions agree that a single monitoring well doesn't provide enough hydrogeological information. On the other hand, there are budget issues to consider. Monitoring plans should do more with less, otherwise, if too many wells are required, marginal costs will increase with a "Swiss cheese" monitoring well approach. Some have suggested that three monitoring wells per ASR well would be an appropriate number. The discussion did not specify if these were three storage zone monitor wells or multi-zone clusters. 

2) What is the optimal size for an ASR facility?
Some contend that the facility should begin with one well and then add wells in phases. Background hydrogeologic data is important; when putting in wells, should plan to collect cores to have an understanding of where to put monitoring wells in the future. Core is invaluable with respect to hydrogeological characteristics and geochemistry of the aquifer. Tremendous amounts of information can be gained from collecting and studying cores. Consultants should check with the Florida Geological Survey (FGS), as they may already have cores from the area.

Utilities struggle with what is minimally required to operate an ASR well field without expensive research that is hard to justify. More requirements tend to lead the utility to consider that ASR is less cost effective. One option would be for utilities to collect data that researchers can analyze. Monitoring costs will eat any project budget; some suggest that “hedging your bets” is necessary. In addition to coring (or perhaps as an initial alternative) surface and borehole geophysics is the way to go; some methods (i.e., surface methods) are yet unproven but they relatively inexpensive to try.

3) What advice regarding drilling and testing permits do those from the western states have to offer?
Some states only require a 50 foot seal at top to drill a well. Permitting is relatively faster than Florida. In Florida, some regulators feel that the process of ASR exploration and system design has a disconnect; hydrogeologic data is generally collected after ASR system design rather than before. Potential bias with regard to isotropy of a particular setting was discussed. Need to carefully consider what the data is really indicating.

One suggestion as a goal for ASR V is to take a model already set up to test sensitivity to target storage volume.  What happens if a high-TDS front is pushed away from the ASR well to the point that there is no longer a concern over the poorer quality water?

4) What benefit do utilities get out of spatial monitoring?

Monitoring should be done with a purpose and have a measure of whether or not it is successful. One measure of success can be whether a permit is granted. A word of caution: if the zone is behaving like matrix flow system, one may pick the wrong storage zone, which may put into question whether additional monitoring is needed.

5) The value of ASR Data ... CERP has done a lot for research in Florida, but specific research is needed to specifically address issues for local utilities. Most ASR sites come with a grant application for monitoring design, etc. By permit, the utility is only required to put in one monitor well. Could the American Ground Water Trust (AGWT) fund additional monitor wells? A member of the AGWT board stated that the AGWT is educational, and can help facilitate discussion or find organizations that can provide funding, but direct funding is beyond the AGWT mission.

The FGS doesn't have budget for major projects with multiple wells; however, it is the state repository for geological data and samples, including cores and cuttings, geophysical data, well construction data, etc. The data and samples are available for research purposes.  Within limits of available staff and funds, the FGS may be able to assist with data collection if a utility is considering coring. For example, the FGS may be able to run the permeability analysis and send samples for geochemical analysis, all of which contribute to the state's understanding of the hydrogeological framework.

The value of information is what is being questioned in this discussion. It depends on what one does with the information. For permitting, water quality changes are a concern. If in the long run, water and money are conserved by gaining information on storage and recovery efficiency, then there is value for monitor wells. It depends on the issues being faced. We are “co-owners of a piece of Swiss cheese.” Monitor wells and their design are a worthwhile investment to reassure the public, as well as good for research.

In one example, a facility had an ASR well with no monitor wells. They are trying to re-permit, and the utility has spent $1M on re-permitting, plus another $1/4M for new monitor wells. If small-scale cycle tests could be performed, ASR wells themselves could be used to test aquifer properties. There are some ASR wells that don't work. The less money available, even if one is sold on ASR, the more testing at small scale is needed. If the test is not affecting anyone else (i.e., beyond the property?), then monitor wells can be used to design expansions. That's easy to sell - use monitor wells to determine where to site future wells. But utilities get discouraged with extensive monitoring requirements.  Some contend that permitting in Florida is conservative, and it is stuck with a lengthy administrative process (30 day waiting period, etc.); it may take a year to permit facilities.

6) Water quality discussion Is the concentration of color being reduced during storage? Yes, if color is tied to iron and VOC, but there is very little data - few sites collect VOC data, although they collect color data.  Data for cations and anions are being collected and lab costs are going down. Some recommend taking fewer samples, but take them consistently throughout the cycles, at both ASR well and monitor well. Regarding lab costs, if samples are below a certain TDS, multi-element, multi-method analyses can cost <$50/sample. Another suggestion is to do surrogate testing, such as measure TDS and conductivity, etc in the field, real time. One does not need a lot of numbers, just strategically placed numbers (i.e., data).

7) At what TDS concentration does buoyancy become an issue, and what effect does that have on recovery? Some suggest that if TDS is less than 5000 mg/L, then it is insignificant, more so at 7000-8000. It is guaranteed to have an effect at 30,000 mg/L. Others contend that at 4000-5000 mg/L buoyancy start to take effect. The thickness and geometry of the aquifer is also a consideration.

At the Marathon ASR, extensive data existed after 12-13 cycles; it was determined that recovery rates depended on how long water was left in storage. Seventy to 75 percent efficiency was observed for a short period, and it dropped over time. They could compensate for the loss.

At a Fort Lauderdale site, injection and recovery rate were evaluated. When the injection rate was reduced by half, the recovery rate went way up.

8) What is the importance of ASR for third world countries? In light of the complexity of ASR, can it be or has it been successful in these parts of the world?
Managed aquifer recharge is being used widely in developing countries. There are currently more than 500,000 operable ASR schemes in India where they drill down through key subsurface horizons and create cavities for storing storm water runoff. The stored water is then either used for supply or irrigation. Similar operations also exist in Indonesia, Philippines, Thailand, and Pakistan. The current need is to develop a skilled work force in those regions to support the technology and ensure that the systems are sustainable.  The goal in those regions should therefore be to provide information on the sorts of problems that can occur, management techniques, monitoring that is required to evaluate performance, maintenance techniques, etc. so that locals can make the necessary decisions as they move ahead with the technology.

Friday April 16

Approach to Arsenic Issues

1) Arsenic MCLs New MCLs become effective in Florida in January 2005 and everywhere in January 2006, however, one can get a federal exemption between 2005 and 2006. The idea that As problems are eliminated after successive recoveries is interesting, but it needs more study. The issue of As release and mobilization is complicated, requires release in certain sequence with certain redox conditions. Arsenic attenuation has occurred at ASR facilities that have expanded. Hypothesis testing can proceed at three sites. This testing, however, takes months to complete, and peer review of the assessment is needed.


In theory, if no parameters change between successive cycle tests (such as keeping constant pumping rates, volumes, pH, DO, recharge water quality, etc.) the As that may enter the flow system (such as due to oxidation/leaching of pyrite) will eventually drop below MCL. In layman's terms, successive cycling may "clean the sponge." If the parameters do change (usually the case) and/or the injected water encounters "new" aquifer matrix, the system may be reset and As may again become an issue. Richard Roth in Wisconsin observed As during storage, however the monitor well is reportedly ~ 50 feet from the ASR well. It is a delicate system.  To a certain degree, this can be tested at the bench scale and with geochemical modeling.

In parallel with work at new ASR sites, we need to look at existing ASR sites and get new data from old sites. The caveat being that the data from the old sites is the right kind of data: Need to consider sampling frequency, detection limits, etc. ICP had different As detection limits in the older data.

2) Is there anything besides As to look at? FGS studies indicate molybdenum, and other metals are mobilizing, however, they are not on the radar as much as As.  Some of the observed mobilized metals don't have MCLs.


3) What can be added to water to prevent oxidation? Pre-treatment such as degassing and recharge water additives are being considered.  Chemical engineering expertise is needed. The aspects are being explored.

4) Moderator presented a scenario for discussion: If an ASR system can demonstrate with modeling that after five cycle-tests, all water quality standards are met and "all" recharged (and affected) water has been recovered, yet, the first few cycles would exceed MCLs, can one proceed after 2006?


5) Scenario Discussion:  Early cycle-test recovery water must be treated. Currently, however, the recovered water is being treated. The catch is what happens when the water comes out – the USDW is being degraded with no guarantee that affected water is not moving off property. What would the state need to do to allow cycle testing and demonstrate progress in addressing the issue?


According to current federal regulations, if you mobilize a metal above MCL during ASR, it's not legal, even if showing improvement. State officials are uncertain what can be done after 2006. Some flexibility exists with As and other issues, for example, the City of Tampa has been trying to demonstrate that As will become non-issue. The question now is: what if a new system comes on line after 2006, As shows up in first cycle with testing at wellhead? We as regulators need answers.

Some contend that if recovery efficiency above 100%, affected water is not pushing further into the aquifer; on the other hand, that depends on how recovery efficiency is defined. Some geochemical models and field results indicate that As will precipitate some distance from wellhead, as was found in Holland. A clear definition of recovery efficiency is needed in order to compare sites. If recovered water is the same quantity and it's the right quality, it meets utilities' needs.  It may be possible to push As to the edge of the "bubble" where it re-precipitates, but we need to focus on the As that doesn't re-precipitate at edge of the "bubble."

6) Where is the regulatory stance on recovery efficiency? The FDEP ASR workgroup is addressing this. Discussions include restricting it to volume or water quality. Ultimately, the volume you put in is the maximum you take out, which is no problem as long as water quality standards are met. But what happens in aquifer?

7) Can we do cycle testing after 2006?   Agencies and consultants need an answer now regarding implementation. DEP, EPA Region IV, and EPA headquarters need to have a transparent process, and should include the applicants in the discussion. We can't wait long for an answer; would want to participate in that process, provide data, and help to solve the problem. These comments will be brought to the attention of DEP officials.

ASR Systems ( David Pyne ) has been encouraged to move forward with a position paper on ASR and requests that any contribution to the effort be provided to them. We will help ourselves and the agencies by getting that information out to environmental groups, decision makers, etc. It was pointed out that such a position paper would have added credibility if state agencies were to give it their blessing. Such a paper would need to be peer-reviewed to by a balanced panel of stakeholders and experts.  An unbiased, well distributed position paper can be very valuable. There is cutting edge research underway that could be shared. Many ASR sites working in Florida, have been operational for many years, but it doesn't work at every site.

Permitting Issues

8) How can the permitting process be improved? EPA Class V looked at all 23 categories, and ASR was recognized as different. It is possible that the AGWT and Ground Water Protection Council (GWPC) could be approached to come up with framework and communication across agencies, federal and state, to look at UIC and related ASR regulations. Use momentum of AGWT meetings to get on GWPC's agenda as a separate meeting.


It was noted that the GWPC will have ASR planning workshop in 2005 in Colorado (tentative), and they will coordinate with the AGWT.

All of these ASR projects are our drinking water supplies, and the purpose of UIC programs is to protect DW supplies. If states try to sort out the issues from the bottom up, it doesn't work. There needs to be consistency with federal regulations. EPA needs to lead the discussion from headquarters level. Many can't work within existing regulations - must be changed at the federal level.

144-12, which pertains to movement of a contaminant into a drinking water source, is left to regions/states to interpret (non-endangerment standard). This would require high level (i.e., Congress) to implement the changes. Regional offices will decide if states are making reasonable interpretations.

9) Have western states looked at ASR as thoroughly? There is some reason why AZ has a tremendous amount of ASR for 8-10 years, EPA is aware that they have 700 foot radial compliance zone; reclaimed water in fresh aquifer. In Florida, many are recharging to brackish aquifer with freshwater and testing at wellhead.

10) What is the relationship between 62.528 and 144.12? Florida 62.528 must be as strict as 144.12. It is actually more strict (i.e., monitoring wells). To get primacy, Florida had to meet EPA requirements at the minimum. Region IV EPA required Florida to state non-endangerment at point of discharge (same as point of injection) when getting primacy.

Looking at barrier islands, 400 gpd/person is used mostly for irrigation of plants. If one can inject stormwater and reuse water to use island and coastal aquifers as storage facilities for irrigation of plants, this would extend our water supplies.

These regulations are not just to protect drinking water directly, but also to protect aquifer and wells around the ASR well. Even though water may be good enough for agricultural purposes coming up, it may not be good for potable supply wells nearby. State regulators underscored that this captures the main point: we need to be concerned about other uses nearby. Another state has aquifers designated only for irrigation to preserve other aquifers for drinking water, however Delaware considers all aquifers as USDW.

A differential protection policy could include steps between potable limit and groundwater regarding which waste can be injected. Perhaps create UIC Class VI. There is more agricultural use of water in FL than potable use; perhaps recharge to brackish aquifers with reclaimed water would make other aquifers available for drinking water supplies.

Some environmentalists consider a limited aquifer exemption process to be a license to pollute. If a major aquifer exemption petition is needed, one must demonstrate that it is in the best interest of the state. That petition would have to go to EPA headquarters. A final comment noted that if ASR can't be used, people will install more desalination plants; and also asked the question: does the EPA wants a negative view of ASR?

11) What is the difference between a variance and an exemption? Some are not optimistic that exemptions will be successful. For example, the Miami-Dade facility said they would go with limited exemption process, but it is very costly. Miami Dade west well field cost $2.8M, and they added another $2.8M to build a treatment plant to deal with coliforms, which many contend die when entering the deep aquifer. Some suggest a need to go back to Congress to tell EPA to follow federal law.

There are problems with UIC funding, which only receives $20M. The GWPC has been trying to increase this funding. There needs to be an integration of surface water and groundwater between the Clean Water Act and the Safe Drinking Water Act. ASR may be the key to that integration. There should exist a Best Management Practice (BMP) for surface water, rather than UIC Class V having more funding and people to deal with this issue. A half-baked idea?  This may require congressional action... just food for thought.

Summary & Closing Comments

Last updated: June 07, 2005

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