At the Aug. 6 meeting of the Osceola City Council, Mark Seip with Veenstra & Kimm (V&K) delivered an update on the proposed injection well for the recirculation project that the city has been looking into since last summer.
Project recap
In August 2023, the council approved a professional agreement with V&K to study a recirculation concept.
The project proposes to recirculate treated effluent from the new wastewater treatment plant back into the West Lake watershed. The effluent would be recirculated on a periodic basis to help bring water levels back up in West Lake, which is Osceola’s only water source.
Estimates vary on how many gallons of effluent would be produced, but it is believed that the water would be of a better level than the current water, as it will be void of nutrients.
If approved by the Iowa Department of Natural Resources (DNR), the effluent reuse plan is the first of its kind in Iowa.
Council action recap
Earlier this year at the Feb. 6 city council meeting, Seip had reported to council that the DNR had questions about chloride waste that would come from the effluent, stating that chloride storage would be needed. This waste would come from treating the effluent, including a reverse osmosis system that would create a waste stream with a high concentration of chloride waste, which is a pollutant to the environment.
That waste would then be cleaned again to concentrate it even more, leaving a final byproduct that would need to be stored. In some areas, chloride byproduct is discharged into a water source such as a large river, but that is not possible here. Therefore, one idea of what to do was to use an injection well. This type of well injects the fluid underground. The type of well constructed depends on the type and depth of the fluid that would need to be injected into the ground.
At the Feb. 20 meeting, council approved entering into an agreement with Petrotek Corporation for a “Deep Injection Well Feasibility Study;” Seip had previously worked with Petrotek on a project in Kansas.
On May 21, Osceola city administrator Ty Wheeler presented council with a report from the initial study done by Petrotek for the injection well.
The report stated that a favorable injection site for the chloride waste would be the Mount Simon Formation, at a depth of about 3,300 to 4,500 feet. The Mount Simon is one of the oldest aquifers in the Midwest, and is composed of various types of sandstone. It is deeper than the Jordan Aquifer, which has been looked at before as a potential source of drinking water. Different types of permitting were then discussed.
Types of permits
There are three types of potential permits that could be obtained for the injection well, and the type be determined by Region 7 EPA based on the total dissolved solids (TDS), which measures native salinity of water in the aquifer; doing this would require a test well.
The first type of permit is a Class 1 UIC (Underground Injection Control) Permit.
In this permit, the TDS measures above 10,000 mg/L (milligrams per liter). Federal regulations designate an underground source drinking water as being any source with a TDS that measures below 10,000 mg/L. In this case, there would be no permits necessary to meet drinking water requirements. This would be the preferred type of permit, as it contains the least amount of restrictions and governmental red tape.
The next type of permit is a Class 1 UIC Permit with a Federal Aquifer Exemption. This occurs when the concentration of TDS is over 3,000 mg/L, but less than 10,000 mg/L. Due to this being within the federal guidelines for underground drinking water, the city would have to pursue a federal determination that would assign the injection zone as non-drinking water, and the water could not be degraded any further.
The report stated this type of permit and determination had never before been done in the EPA Region 7 district, and therefore would be difficult to pursue.
The last type of permit option is a Class 5 UIC Permit. This would require the composition of the injection waste to be better than or equal to the native TDS of the injection zone, so as not to degrade the water in the aquifer any further.
Simon v Jordan aquifers
The Jordan aquifer wells in south central Iowa have TDS measurements of 1,600 to 1,700 mg/L; the water quality decreases the further into the aquifer one goes.
Alternatively, Petrotek had identified two, Mount Simon UICs in Louisa County, with water quality reports showing those wells to have TDS ranges of 9,290 to 11,260 mg/L. This seemed to be the best option for an injection zone, assuming the Mount Simon aquifer in this area would also have a higher concentration of TDS.
To determine this, however, a test well would have to be pursued, which would require consultation with the DNR.
At the time, it was estimated that the injection well would be about 4,000 feet deep.
Aug. 6 updates
At the Aug. 6 meeting, Wheeler recapped the update from May, stating that the Mount Simon aquifer continued to appear to be the most feasible solution for the chloride waste. He said the next step was to drill the test well and running samples to see what type of permit could be applied for, with the continued hope that they would qualify for a Class 1 UIC. The test well could then be used as the injection well, as it would be cased.
Seip reiterated that this would be the first well of its kind in Iowa, but is commonly done in the West. He said this injection well test is the trigger point, or first hurdle, for other stages of the project. There is an estimated four-year timeline on the project, as it will take Region 7 EPA 18 to 24 months for just the permitting process.
Seip explained this time frame as being due to the amount of permits the EPA does across several states, meaning Osceola would to wait in line.
In the meantime, however, everything else needed for the injection well could be built and set up, including a building and salt cells, just waiting to go online.
“We’ll be in operation just waiting to use the well,” said Seip.
When asked where the contaminants go, Siep explained that the waste would go into the porous Mt. Simon aquifer where it would be confined. There are no wells currently drilled in the area that would affect that, a problem that can arise in some places where many such wells exist and the waste can escape to the surface via a different well.
The proposed injection well here would have an estimated lifespan of 50 years.
A discussion was held regarding chloride waste, which is of concern regardless of the recirculation concept.
“Even if the DNR were to render an opinion at some point that hey, you just simply aren’t ever going to recirculate this back to West Lake…there remains this chloride puzzle,” said Wheeler.
Discussion came to Hormel Foods, their chloride waste and involvement in the injection well project. A meeting is planned to be held with city staff, V&K and Hormel to discuss further.
Minutes from the Aug. 6 meeting are available on the city’s website.