January 12, 2002

Ms. Huxhold-Fliss:

I wanted to thank you for arranging the opportunity to tour the Lemon Lane Water Treatment Plant here in Bloomington on January 8, 2002. It was extremely informative. Your Earth Tech associates were extremely knowledgeable and communicated important information in an open and generous manner. I do have a number of comments to explain and amplify my questions and observations during the tour.

I know that more than once I expressed my concerns that the facility was operating successfully as a water management plant, but may not be as successful as a PCB remediation facility. My reservations involve both the treatment process itself and on monitoring performance. Despite being a well-constructed and operated facility, it may actually not be addressing the primary problem of prevention of PCB release from Illinois Central Spring, nor monitoring whether the system works effectively.

1) The process collects spring water exiting the hillside north of the railroad tracks, after it travels about 15 feet in the open air over a gravel bed, flows into a 24-inch pipe which carries it under the railroad tracks and then empties into a deep sump at the treatment plant. The contaminated water is open to the air and subjected to turbulent flow in the streambed, the collection pipe, and to extreme turbulence as it dumps into the sump. Further, the water is exposed to the atmosphere throughout the plant in filter equipment and holding tanks (including the outside storage tanks).

This approach in collection and treatment shows a fundamental ignorance of the basic physical chemistry of polychlorinated biphenyls (PCBs) and many other organic contaminants coming out of the site. Many organic compounds, including PCBs are readily volatized from water by the system's turbulence and open-air process. Much of the removal of contamination by the system is very likely due to transfer to the air. This bypasses the filtration and granular activated carbon (GAC) extraction technology, and releases hazardous substances to the environment.

To give you some idea of this potential, I have prepared the attached data table and graphics. These data are from Environmental Organic Chemistry (Scwarzenbache and others (1993) Wiley Interscience). I have included parameters on a suite of compounds including polyaromatic hydrocarbons (PAHs), PCBs, and a few other hydrocarbons spanning a range of molecular weights, solubilities, and vapor pressures that show the effect. Please note the inclusion of something called the "Henry's Law Partitioning Constant" in the table and a graph. This index provides the best measure of a compound's tendency to volatilize from water. Vapor pressure of the pure compound is not a sufficient indicator of volatility from water. In fact, many volatile compounds have sufficient water solubility that air sparging is ineffective in removing them.

The data show that partitioning from water to air can be significant for those compounds with a Kh greater than about 10-4. Organic substances such as naphthalene, hexachlorobenzene, trichloroethene (TCE) and tetrachloroethene (PCE) are frequently stripped from contaminated water using air sparging. This also occurs for PCBs with chlorine substitution up to about six (depending on air flow, turbulence, process time, and so on). The potential for air stripping through turbulence and exposure occurs at many points in the facility's collection and treatment process. In the atmosphere, these substances add to local air quality impacts and contribute to the increasing national and worldwide pollution burden.

2) It is my understanding that the extent of system performance monitoring involves sampling and analysis of filter-press solids and exit water sent downstream to Clear Creek. No mention was made of the frequency of sampling of solids and exit water, and whether it was based on time or volume of water treated. Sludge sampling apparently is done only for disposal purposes (the landfill acceptance criteria are what?). I recognize that the system is still in a "shakedown" phase without an operations manual, but the paucity of system performance monitoring is even more questionable for that reason. Not only is it necessary to monitor water and sludge to meet disposal and water criteria, but it is critical to understand the effectiveness of the system to remediate contamination based on what is coming out of the spring under a wide range of flow conditions.

Additionally, the sampling that is done is somewhat haphazard and likely to give inaccurate results. This includes both water and sludge sampling. Water samples are taken from the sump by an automatic sampler after significant air exposure and turbulence downstream from the spring. Additionally, samples are left in open containers exposed to the air, which causes further loss. Although, no sampling of effluent was observed, even greater care should be taken with effluent samples to ensure their validity to show that no contamination is in released water.

The sludge sampling also does not to be done on a systematic basis to understand PCB association and extraction effectiveness, but more as grab sampling of a dumpster load to satisfy landfill disposal documentation. Because of the difficulty of composite sampling of wet material and the volatilization problem, overly simplified approaches may not give sufficient valid data to evaluate correct PCB removal. Again, PCB loss to the atmosphere from sludge accumulating for weeks does not represent proper protection of the community and world from this contaminant. Why even bother to treat water if all the contaminant is not captured?

System performance monitoring requires acquiring an understanding of PCB flux at all system stages. Such a "mass balance" approach begins with measuring the levels of PCB contamination released from the spring during any circumstance of flow particularly those with potential for flushing of sediments. Because the treatment system is undersized for potential rainfall events (capturing only 70% of a 25 year storm event?), understanding the correlation of flow and PCB content is critical to optimize system performance and minimize environmental damage.

If water volume alone is the capture criteria, significant PCB releases during some events may be bypassed when the tanks are full of relatively less contaminated water. That this is a potential can be seen in the patterns of PCB release and flow developed by CBS during closely successive rainfall events. Flushing of contamination can occur when water levels are high and access relatively isolated pockets of contamination in the karst. Examples of this phenomenon have been sent to the EPA in the past and its potential should not be ignored as the system operations guidance is being developed.

There appears to be no systematic study of the effectiveness of solids removal and how much contamination is associated with particulate matter of different size. The fineness of filter media may have to be adjusted if PCB levels are closely associated with particles such as colloids of less than 0.5 micron.

Assessing the GAC performance is also not done in a manner suggesting an attempt to assess effectiveness. Operating under a "mass balance" approach that understands what portion of the PCB load is present as dissolved would lead to predictions of GAC accumulation rates and breakthrough times. This requires more sampling of water PCB dissolved concentrations and correlation with GAC capacity. Currently, the system appears to be underutilizing its design capacity in that little PCB accumulation on the GAC is occurring.

The reported levels of PCBs in finished water may actually be higher than what GAC can achieve. This suggests an operation problem. The octanol-water partition coefficient of PCBs (see attached table) strongly favors PCB absorption by organic substances such as GAC. Any occurrence of PCBs in water passing through the GAC system suggests that either residence times are too low for complete sorption, or that plugging with clay, or biofouling has impaired the capacity of the GAC. If mechanical filter fineness is too large, colloidal material may be accumulating in the GAC, or worse, even passing through the GAC allowing sorbed PCBs to leave in the effluent. Carefully designed, systematic studies are necessary.

In summary, I believe that improvements in both the system design and the monitoring of system performance are needed. The exposure of the water to air and potential for release to the atmosphere destroys the system's effectiveness as a PCB remediation. The system design should be re-evaluated and air exposure points should be corrected to control emissions. And, because the system is operated primarily as a water management program and not a PCB-removal system, its performance is not being monitored adequately. Correct sampling and accurate analysis at numerous "before and after" points needs to be instituted to assure that system components are working completely. Because the system is undersized for potential runoff events, optimization of its capability is critical to effective PCB removal. There is little indication that understandings of PCB release, sediment loads, particle size and PCB association, and water flow are being achieved. Finally, it should be obvious from these observations that the effective functioning of the treatment system would benefit from rapid completion of the operations manual. And, long before it is finalized, the community should be given the opportunity to contribute to its formulation. Deficiencies that are occurring need solutions to prevent the weaknesses from growing worse.

If you have any questions or comments on these observations, I would be happy to discuss them with you or your colleagues. It is important to have effective remediation of all exposure pathways at all sites, and this effort at Illinois Central should be a best effort to set a standard for further remediation at the other sites. Thanks again for your assistance in helping the community to understand what is being done by our government agencies in remediating the environmental impacts from these Superfund sites.

Sincerely,
Joseph G. Hailer