August Community Update: Wet Cake Removal Continues

The below information has been provided in an effort to help keep the community informed on a more frequent basis about progress at the AltEn site. 

Ever since AltEn ceased operations at its facility in Mead in 2021, the AltEn Facility Response Group (FRG) has been voluntarily working under the guidance of the Nebraska Department of Environment and Energy (NDEE) to stabilize the AltEn site and develop a Remedial Action Plan (RAP) for the site. The FRG’s top priorities have been and continue to be to help ensure the safety of the surrounding community and environment. To-date, there has been no evidence of impacts to local drinking water.

The FRG is working diligently with the NDEE to identify the most effective and safest methods to address the current environmental conditions on the AltEn site. The remedial action plans (RAP) will recommend remediation for components remaining on-site, including wastewater, sludge, and wet cake.

August 20, 2024

Wet Cake Removal

Evaluation of optimizing wet cake solidification and transportation continues, focusing efforts on moving more wet cake off-site – and doing it faster – with an eye on safety.
Wet cake removal continues​ Transported 925 truckloads (19,420 tons) of solidified wet cake to the landfill in 2024 (as of Aug. 19)​ Total of 1,332 truckloads (29,628 tons) since 2023​ No perimeter air quality triggers​ Adapting process to variable wet cake characteristics​ Continuing to evaluate opportunities for improvement; e.g., constructing a second truck wash pad to improve truck traffic flow​

Northeast Lagoon: Liner Removal

Removal of the Northeast Lagoon liner was completed in July. Water continues to be pumped into the Southeast Lagoon for treatment.
Northeast Lagoon Liner Removal Objectives​ Remove the lagoon liner​ Provide space for managing dredged solids from the Southeast Lagoon​ Status​ Completed, other than applying Posi-Shell​ Geotubes are installed and receiving dredged solids from the Southeast Lagoon​ Water from Geotubes and stormwater is being pumped to the Southeast Lagoon for treatment​

Lagoon Liner Removal and Dredging

The efforts to remove total suspended solids (TSS) from the Southeast Lagoon continues through use of a hydraulic dredge, which reduces potential impact to the site’s water treatment plant (WTP) operations. Geotubes reduce the amount of moisture in the dredged solids. Southeast Lagoon dredging is expected to be completed in September.

A similar liner removal process and solids consolidation is happening in the Northwest Lagoon, with the process anticipated to be completed in September, as well.

Several options for lagoon solids have been evaluated and tested.

Southeast Lagoon Dredging Objective​ Reduce TSS concentration in SE Lagoon water to reduce the potential of impacting the WTP operation​ Evaluate ability of Geotubes to reduce the solids moisture content​ What is being done​ Removing solids using a hydraulic dredge​ Pumping dredged solids into Geotubes located in the NE Lagoon​ Pumping water drained from the Geotubes and stormwater to the SE Lagoon for treatment​ Permit issued by NDEE​ Expect to complete in September​
Northwest Lagoon Liner Removal and Solids Consolidation. Objectives​ Evaluate liner removal and​ solids consolidation process​ What is being done​ Using the same approach successfully used in the NE Lagoon​ Transporting liner to the landfill​ Collecting drained lagoon and storm water and pumping them to the SE Lagoon for treatment​ Consolidated solids will be covered with Posi-Shell when completed​ Schedule​ Started work in at end of July​ Expect to complete in September​

Stormwater Best Management Practices

Stormwater best management practice (BMP) improvements along the North Ditch continue​. This phase of work is expected to be completed this month. 

Stormwater BMP Improvements Stormwater best management practice (BMP) improvements along the North Ditch continue​ This phase of work is expected to be completed this month​ ​

Lagoon Water Treatment and Land Application

As of mid-August, nearly 100 million gallons have been treated at the on-site treatment plant; an estimated 25 million gallons remain to be treated, excluding stormwater. Treatment is expected to last through the end of the year, though may take longer with continued rainfall. In addition, more than 60 million gallons have been applied to land through Spring 2024. Land application will continue through 2025 until all treated water is applied.
Lagoon Water Treatment and Land Application Water treatment​ Treated a total of ~98 million gallons through Aug. 19​ Analysis continues to show good water quality for land application​ Estimate ~25 million gallons remain to be treated, excluding stormwater​ Expect to complete treatment at the end of 2024 pending​ rain and stormwater accumulation​ Moving back to operating 24 hours per day this week​ ​ Land application of treated water​ 60.9 million gallons have been land applied through Spring 2024​ Planning to land apply ~38 million gallons across 1,147 acres ​ Expect to commence land application in September and continue into November – NDEE review and approval ongoing​ Spring and Fall land applications will continue in 2025 until all treated​ water is applied
Lagoon Solids Treatment Options Evaluation​ Options and Testing​ Description​ Schedule​ Solidification Treatability Study​ Improve physical properties for landfilling​ Bench-scale testing​ Lagoon solids are different than wet cake and bentonite does not work for them​ ​ Started in 2022​ Expect to complete in November​ Solidification Field Trial​ Field-scale testing in Northwest Lagoon to confirm bench-scale testing results and optimize solidification reagent and dosage​ ​ Started planning this month​ Complete in November​ Expect 4-6 weeks of field effort​ ​ Landfarming and Daramend Treatment Treatability Study​ ​ Reduce pesticide concentrations quicker and may also improve physical properties​ Solidification likely required for lagoon solids​ Field testing​ ​ Started in March​ Expect to complete in November​ Thermal Drying Treatability Study​ Reduce water content and volume of solids​ Bench-scale testing​ ​ Started in May​ Complete in December​

Groundwater Monitoring – June 2024

Groundwater samples were collected in June, with results showing normal pesticide screening levels that are representative of the region’s groundwater quality. There was an exception of one compound in MW5, which is located in the northwestern part of the site: Nitrogen compounds are present in background groundwater, though are representative of regional groundwater quality.
Groundwater Monitoring Results – June 2024 – Nitrogen Compounds ​ Nitrogen compounds are present in background groundwater and representative of regional groundwater quality​

Other Site Activities

We have made progress with several other on-site activities: Northwest Lagoon subsoil sampling is completed, with results to be shared in September; the new on-site tornado shelter has been installed; new air quality monitors are being set up; groundwater sampling will be done in the coming months. 

Other Activities Northeast Lagoon subsoil sampling completed in July; results expected in September and will be shared with the community​ New air quality monitors have been installed​ On-site quarterly groundwater sampling event will occur week of September 9​ New tornado shelter installation completed​

Stay Informed

Check alteninfo.com for the latest updates about AltEn site activities.

AltEn Facility Response Group

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