2-SOLIDS MANAGEMENT PLAN - I-35 ,,-65 WASTEWATER LAGOONS.pdf

Solids Management Plan

Kansas Turnpike Authority

Towanda Service Area

I-35 MM-65 Wastewater Lagoons August 11, 2026

Prepared by:

Kyle Otto, PE:

kotto@jeo.com 402.419.3466

Andrew Fischer, EI afischer@jeo.com 785.249.3551

JEO CONSULTING GROUP INC

534 S Kansas Avenue

Topeka, Kansas 66605 785.836.4141

Offices in:

Nebraska, Iowa, Kansas, and South Dakota

JEO Project No. 260715.00

2026 Solids Management Plan Kansas Turnpike Authority

JEO Consulting Group, Inc. 1 August 2026

Contents Lagoon Overview

Statement of Purpose

Design Summary

Depth Measurements

Measurement Method

Calculation of Sludge Volume

Sludge Sample Test Results

Sampling Method

Pollutant Concentrations

Nutrient Concentrations

Vector Attraction and Pathogen Reduction

Sludge Removal Process

Desludging Options and Methods

Potential Land Application Sites

Sites, Land Use, and Area

Required Area of Application

NRCS Soil Data Summary

Analysis of Potential Water Contamination

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Figures

Figure 1: Project Location Figure 2: Site Layout Figure 3: Lagoon Flow Schematic Figure 4: Cell #2 Lagoon Depth Measurements Figure 5: Potential Sites for Land Application Figure 6: FEMA Flood Risk Map

Tables

Table 1: Lagoon Depths and Volumes Table 2: Lagoon Dry Sludge Weight Table 3: Sludge Pollutant Concentrations Table 4: Sludge Nutrient Concentrations

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Lagoon Overview

Statement of Purpose The Kansas Turnpike Authority (KTA) operates three (3) cell wastewater treatment lagoon system

(lagoons) for sewage treatment at the I-35 Towanda Service Area at mile-marker 65. The facility is located along I-35 approximately 2 miles south of Towanda, in western Butler County, KS. Recently, the KTA has experienced plugging of the inlet and transfer pipes within the lagoon facility. It was initially believed the plugging was a result of accumulated sludge within the lagoon cells, therefore, KTA pumped most of the water out of Cell #1 to evaluate further. KTA contracted with JEO Consulting Group to prepare a Solids

Management Plan, prepare necessary documents required by KDHE permits, and prepare contract documents required for solicitation of bids for biosolids removal from the lagoon cell(s). The project location is shown in Figure 1. A map of the site is shown in Figure 2.

Figure 1: Project Location

The solids management plan identifies potential sites for land application nearby and reviews applicable

KDHE regulations defined by the USEPA 40 CFR 503 forms. A copy of the partially filled USEPA 40 CFR 503 forms is provided in Appendix A and the forms shall be completed by the Contractor when sites are officially determined for land application and soil samples for these sites are collected.

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Figure 2: Site Layout

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Design Summary The facility has three (3) wastewater lagoon cells providing domestic sewage treatment. The lagoons were redesigned and reconstructed in 2003 and have a rated treatment capacity of 35,680 gallons per day

(GPD) of domestic sewage with a detention time of 200 days at the permitted flow rate.

Cell Surface Area (Acres) Maximum Water Depth (ft) Cell #1 (Primary) 1.33 7 Cell #2 (Secondary) 1.25 7 Cell #3 (Tertiary) 0.50 8

Sewage waste from the service area flows by gravity to a flow distribution box, which distributes flow to the primary lagoon on the north side of the cell. The distribution box can also be used to route flow to the secondary lagoon should the primary lagoon need to be taken out of service and serves as an overflow for the distribution box if the Cell #1 effluent line backs up and overtops the removable weir plate. During normal operation, flow exits Cell #1 at its southeastern corner and into the southern part of Cell #2, exiting

Cell #2 at its northern corner, and flows into the northwest corner of Cell #3. Flow exits Cell #3 at its eastern edge through a sanitary sewer line which discharges to a ditch that runs North under I-35. Based on the KDHE inspection report dated March 15, 2024, the lagoon system has not discharged in over a decade.

Figure 3: Lagoon Flow Schematic

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Depth Measurements

Measurement Method Depth measurements of lagoon cells #1 and #2 were performed by the Kansas Rural Water Association

(KRWA) in March 2026 using a device called a sludge judge. This device is a clear plastic tube with a check valve (one-way valve) on its bottom end. To take sludge and water depth measurements, the tube is slowly inserted valve-first into the lagoon until the bottom is reached. The device is then lifted out of the lagoon and the check valve engages to hold the column of water and sludge in place. Gage markings on the outside of the tube allow for the measurement of sludge depth and total depth. Multiple readings are required to form an accurate measurement of sludge volume for each cell.

Readings in Cell #1 indicated greater depths of sludge near the inlet and outside edges of the cell. Readings around the edge of the cell had a sludge depth of nearly 3 feet, whereas the middle of the cell was 14 to

16 inches. The average reading depth was assumed to be 2.25 feet.

Cell #2 readings were more consistent with an average sludge depth of about 8 inches. The results of the sludge depth measurements are shown in Figure 4.

Sludge depth was not measured in Cell #3.

Figure 4: Cell #2 Lagoon Depth Measurements

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Calculation of Sludge Volume The total depth of sludge in cells #1 and #2 were calculated using a simple average of the data readings.

JEO is not responsible for the accuracy of the sludge depth readings as they were performed by a third party. Sludge judge readings are known to underestimate the sludge depth due to the resistance of sludge flow through the check valve. This phenomenon was verified by the University of Western Australia article, Application of Sonar for the Measurement of Sludge Heights in Wastewater Stabilization Ponds1. The underestimate was stated at 1.5” to 3” by a North Carolina State University Cooperative Extension article, Sludge Survey Methods for Anaerobic Lagoons2. For this reason, the average sludge depth was estimated as the average of the data points plus 1.5”, as this was the most conservative estimate for the underestimation of sludge height by sludge judge measurement. The actual sludge volumes and subsequent dry tonnage of sludge for land application will vary from these results. Table 1 shows the approximate average total depth, sludge depth, total volume, and sludge volume in each lagoon. Table 2 gives the approximate dry-tonnage of sludge for removal from each lagoon. The dry weight of sludge calculation assumed a specific gravity of solids of 1 and used a percent-solids of 19.4% from the lab results.

Table 1: Lagoon Depths and Volumes

Lagoon Average Sludge Depth (ft)

Approximate Total Volume (ft3)

Approximate Sludge Volume (ft3)

Cell #1 2.38 332,000 96,800

Cell #2 0.79 310,000 28,351

Cell #3 Not Evaluated 117,000 Not Evaluated

Table 2: Lagoon Dry Sludge Weight

Lagoon Dry Weight of Sludge (Tons)

Primary 586

Secondary 172*

*Not Planned for Desludging

Sludge Sample Test Results

Sampling Method The results outlined in this section were tested from a composite sample taken from lagoon Cell #1. The sample jars were packed on ice for the duration of transport. Samples were sent to Meridian Analytical

Labs, LLC for testing.

Pollutant Concentrations The USEPA sets ceiling concentrations for various pollutants, which are the maximum concentrations per dry-weight of sludge for which land application of sludge is permitted, defined in EPA 40 CFR 503 form LA-

1University of Western Australia, Application of Sonar for the Measurement of Sludge Heights in Wastewater Stabilization Ponds

(2010).

2 North Carolina State University Cooperative Extension, Sludge Survey Methods for Anaerobic Lagoons (2008).

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PMC Pollutant Metals Concentration. These pollutant concentrations are used to determine the cumulative loading of pollutants on land sites, defined in Form LA-CPL. Form LA-CPL must be filled individually for each land application site. Table 3 shows the ceiling pollutant concentrations compared to the lab results for the lagoons. KTA’s lagoon sludge did not exceed ceiling concentrations for any of the regulated pollutants.

Table 3: Sludge Pollutant Concentrations

Pollutant Ceiling Concentration, mg/kg dry basis

Lab Results, mg/kg dry basis

Arsenic 75 N.D.*

Cadmium 85 N.D.*

Copper 4,300 3.66

Lead 840 N.D.*

Mercury 57 N.D.*

Molybdenum 75 N.D.*

Nickel 420 2.98

Selenium 100 N.D.*

Zinc 7,500 18.2 *N.D. – Non-Detectable Concentration

Nutrient Concentrations Nutrient concentrations are regulated for the land application of sludge. These nutrients are chemicals that support the growth of plants, which include various forms of Nitrogen and Phosphorus. The concentration of nutrients in sludge directly relates to the permitted loading rate of sludge for land application as defined in Form LA-ANR Agronomic Nitrogen Rate (Appendix A). For sludge of lower nutrient concentration, a greater amount of dry tonnage can be applied per acre of land. The LA-ANR form must be completed individually for each land application site, as the permitted loading rate depends upon the existing concentrations of nitrogen and phosphorus in the soil. As permission to use land for application of sludge is attained from each landowner, it will be the responsibility of the contractor to take soil samples for use in completing the agronomic rate calculation form for each site, which then must be filed with KDHE along with the other forms given in the 40 CFR 503, Appendix A. The existing data regarding nutrient concentration of waste is pre-filled in this form and can be found in Appendix A. Table 4 shows the concentrations of relevant nutrients as determined by the sludge samples taken in Cell #1.

Table 4: Sludge Nutrient Concentrations

Nutrient Compound Concentration of Compound, mg/kg dry basis

Concentration of Compound, lb/ton dry basis

Total Kjeldahl Nitrogen 3,390.8 6.78

Ammonium Nitrogen 1,720 3.44

Nitrate Nitrogen N.D.* N.D.*

Organic Nitrogen 1,670 3.34

Phosphorus 2,820 5.64 *N.D. – Non-Detectable Concentration

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Vector Attraction and Pathogen Reduction Section LA-PR Class B Pathogen Reduction and Site Restrictions and section LA-VAR Vector Attraction

Reduction both lay out standards to ensure that lagoons have undergone enough treatment to reduce the potential concentration of pathogens in the sewage and reduce the potential attraction of vectors

(like birds, rodents, and insects) to the sludge. KDHE and the EPA Region 7 formed an agreement that excludes municipal lagoons from Pathogen (LA-PR) and Vector (LA-VAR) reduction requirements provided that the lagoons in question have not been desludged for at least 15 years, as lagoons meeting this definition have sufficiently treated and stabilized sludge to meet Class B requirements. KTA’s lagoons are

23 years old with no records of desludging operations; therefore, they meet the requirements of the exemptions.

Sludge Removal Process

Desludging Options and Methods KDHE will not allow for more than one cell of a two or three cell lagoon facility to be taken out of service at one time. The cell cannot remain out of service during the winter or spring seasons because these seasons are when the most treatment capacity is needed. KTA’s lagoons have a diversion structure and necessary piping to isolate the primary cell (Cell #1) for desludging.

Options for removal of sludge include dredging and direct pumping of sewage sludge or draining and dewatering of sludge to be removed by excavation. Sludge is preferably pumped directly to the site to be applied by a temporary pumping station. It can be pumped into a vacuum truck and driven to the site if sludge is transported directly to the site for application and no interim storage is used. Lagoons can also be drained so sludge may be agitated and slowly dried at the bottom of the lagoon for removal by excavator. The second option is favorable if improvements are necessary on the lagoon, like changing pipes/valves or reconditioning the lagoon liner. Caution should be exercised by the contractor to ensure the existing liners are not damaged during the construction phase.

Land application methods depend on the land use and remoteness of the site. Wet sludge can be sprayed directly onto the site in some cases but is generally not a preferred method due to the potential odor issues, runoff risks, stricter site access requirements, and longer time periods before crop harvest and animal grazing can take place. Sludge can be injected or ‘knifed’ into the subsurface. It can also be mechanically incorporated into the surface. Dry sludge can be directly land applied or incorporated into the surface. The method of land application will have varying effects on site restriction requirements as outlined in the EPA Part 503 rule and further explained in the guide A Plain English Guide to the EPA Part

503 Biosolids Rule.

Potential Land Application Sites

Sites, Land Use, and Area Six potential sites for land application have been identified. The address, owner name, size, effective size for land application, mailing address, and land use for each site is provided in the list below. Figure 5 provides a map of the potential land application sites. It shall be noted that there are existing wells on or near the potential land application sites. These wells are shown in Appendix F, and a minimum of 200 feet shall separate the perimeter of the land application area from any wells. Sites that have been land applied must sit for 30 days before animals may graze or before crops for animal feed may be harvested. Turf

JEO Consulting Group, Inc. 10 August 2026 grass may not be harvested for 1 year after land application. Further site restriction requirements will be determined pending the interest of potential site owners and site soil testing results. Contractor to contact owners of potential sites to get permission for land application.

1.)

Address: 00000 SW FULTON RD

City State Zip: Towanda, KS 67144

Mailing Address: 7244 SW DRYCREEK RD ANDOVER, KS 67002-8223

Owner Name: TURNER, WENDELL G; TRUST & TURNER, HELEN Y; TRUST

Size: 92 Acres

Available Size for Land Application: 40 Acres

Land Use: Grassland

2.)

Address: 00000 SW FULTON RD

City State Zip: Towanda, KS 67144

Mailing Address: 4680 SW FULTON RD. TOWANDA, KS 67144-8938

Owner Name: BIEHLER, ELIZABETH K; REV TR

Size: 90 Acres

Available Size for Land Application: 65 Acres

Land Use: Grassland

3.)

Address: 00000 SW 50TH ST

City State Zip: Towanda, KS 67144

Mailing Address: 4680 SW FULTON RD, TOWANDA, KS 67144-8938

Owner Name: BIEHLER, BRADLEY A; REV TR

Size: 134 Acres

Available Size for Land Application: 112 Acres

Land Use: Grassland

4.)

Address: 00000 SW OHIO STREET RD

City State Zip: Towanda, KS 67144

Mailing Address: 7419 CENTENARY AVE, DALLAS, TX 75225-4516

Owner Name: QUIGLEY, REBECCA LOOMIS

Size: 150 Acres

Available Size for Land Application: 130 Acres

Land Use: Grassland

5.)

Address: 03543 SW OHIO STREET RD

City State Zip: Towanda 67144

Mailing Address: 3543 SW OHIO STREET RD, EL DORADO, KS 67042-9079

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Owner Name: WILKERSON, ZACK G & JEAN H; LIVING TRUST

Size: 114 Acres

Available Size for Land Application: 60 Acres

Land Use: Grassland

6.)

Address: 06876 SW 40TH ST

City State Zip: El Dorado 67042

Mailing Address: 6876 SW 40TH ST EL DORADO, KS 67042-8918

Owner Name: CORBIN, CAROLYN S; REV TR

Size: 68 Acres

Available Size for Land Application: 55 Acres

Land Use: Row crop

Figure 5: Potential Sites for Land Application

Required Area of Application The amount of sludge that can be applied per unit acre depends on the existing soils nutrient concentration as defined in Form LA-ANR Agronomic Nitrogen Rate (Appendix A). For sludge of lower nutrient concentration, a greater amount of dry tonnage can be applied per acre of land. The LA-ANR form must be completed individually for each land application site, as the permitted loading rate depends upon the existing concentrations of nitrogen and phosphorus in the soil. As permission to use land for

JEO Consulting Group, Inc. 12 August 2026 application of sludge is attained from each landowner, it will be the responsibility of the contractor to take soil samples for use in completing the agronomic rate calculation form for each site, which then must be filed with KDHE along with the other forms required by 40 CFR 503. The maximum allowable rate of dry sludge that can be applied per acre is defined in 40 CFR 503 Form LA-ANR-EZ (short form) as 2.0 dry tons of sludge per acre, which would require a minimum application area of 293 acres based on the total dry solids weight of 586 tons. The amount of land required for application could potentially be reduced using the long form method (Form LA.ANR) depending on the existing nutrient concentrations of soils at the land application sites.

NRCS Soil Data Summary Relevant soil data was populated from the NRCS soil database to determine soil types, physical properties, chemical properties, erodibility, and flood risk of potential sites. This information included reports on soil composition, soil pH, percent sand, and flooding frequency class. This report is provided in Appendix B.

The results showed low sand composition in soil, a factor which is used in the LA-ANR form calculations.

Soil composition was slightly acidic, which is favorable for land application of sludge. The soils data indicated the drainage classes of the most prevalent soil types to be well drained or moderately well drained and indicated depth to groundwater to be greater than 80 inches. Depth to groundwater for land application of sludge is not regulated by KDHE, therefore none of the prospective sites need to be eliminated based on high groundwater, unless soil testing indicates otherwise.

Analysis of Potential Water Contamination Planning must be done to prevent water contamination by runoff on land application sites. For this reason, the land application sites should be in a less than 1%, 100-year flood frequency class. FEMA’s flood hazard map shows that none of the prospective sites were within the 1%, 100-year flood frequency class. This result agrees with the NRCS flood risk database result, showing low flood risk. Flood frequency for each site was determined to occur less than once every 500 years. A map of FEMA flood risk in the area is provided in Figure 6.

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Figure 6: FEMA Flood Risk Map