Evaluation of engineered soils for bioretention areas containing dredged Illinois River sand, compost, biosolids and pyrolyzed biosolids

Authors: Vaughn, Steven; THEILING, CHARLES - Us Army Corp Of Engineers (USACE); ROSENBOHM, PAUL - Lhf Compost, Inc; Eller, Fred; Peterson, Steven - Steve

Submitted to: Crop, Forage & Turfgrass Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/3/2021
Publication Date: 3/15/2021
Citation: Vaughn, S.F., Theiling, C., Rosenbohm, P., Eller, F.J., Peterson, S.C. 2021. Evaluation of engineered soils for bioretention areas containing dredged Illinois River sand, compost, biosolids and pyrolyzed biosolids. Crop, Forage & Turfgrass Management. 7(1). Article e20096. https://doi.org/10.1002/cft2.20096.
DOI: https://doi.org/10.1002/cft2.20096

Interpretive Summary: In order to keep waterways such as rivers and lakes navigable, the United States Army Corps of Engineers performs dredging operations in these bodies of water. The removal of sediment from the Mississippi River watershed is especially important, as over 500 million tons of shipped goods per year use this waterway. Within this system, the Illinois River is a vital link between the Mississippi River and the Great Lakes. Due to the low elevational gradient on the Illinois River south of Starved Rock to the Mississippi River, sand does not naturally get removed from the main channel. Thus, to maintain a 9-foot navigation channel, routine maintenance dredging is performed at various locations along the Illinois River. Annual maintenance dredging is normally required at 5 to 15 sites along the river, and the volume of material dredged is approximately 200,000 cubic meters per year. The dredged sediments are either placed along the shoreline (primarily for erosion control) or in upland sites, generally located close to the dredging sites due to transportation costs. However, storage space for the sand is limited, so value-added uses for it are needed. A research team composed of personnel from several public and private entities was established in 2018 to study beneficial uses of dredged sediments. Initially, our team has focused on the use of dredged sand from the main channel of the Illinois River to produce engineered soils for use in bioretention sites such as bioswales, rain gardens, and along state highways. We found that grass species used by the Illinois Department of Transportation had excellent growth in engineered soils containing dredged sand and locally-produced compost, with good results found if the grasses were grown in engineered soil containing sand, compost, and Greater Peoria Sanitary District biosolids or biosolids pyrolyzed in an oven to reduce odors, eliminate pathogens and chemical contaminants.

Technical Abstract: Dredged Illinois River sand is nutrient poor and has low cation exchange capacity. Engineering this soil by adding amendments to increase nutrient retention may help sustain plant growth and absorb contaminants when the sand is used in bioslopes, bioswales, and rain gardens. The objectives of this study were to compare the physical and chemical properties of engineered soils derived from dredged Illinois River sand combined with mixtures of a locally-produced compost, dried Class B biosolids from the Greater Peoria Sanitary District (GPSD), and pyrolyzed GPSD biosolids, and to study their effect on the growth of a grass mixture designed for chronically wet areas, such as bioslopes/bioswales along Illinois Department of Transportation (IDOT) highways. Dry and wet bulk densities of the soil mixtures increased with increasing levels of both biosolids and pyrolyzed biosolids. Soils containing higher levels of compost were linked to higher CEC, soluble salts, porosity and soil moisture. Shoot and root lengths, and fresh and dry tissue mass were highest in mixtures containing the higher compost levels. These results indicate that the addition of compost to Illinois River sand may be required for adequate grass growth in these engineered soils saturated with water. The use of either biosolids or pyrolyzed biosolids as nutrient sources may need to be supplemented with compost for adequate plant growth.