Washington State Dept. of Ecology 3/27/2025

SSLAP – Lowell Snohomish River Road Agricultural Land ______________________________________________________________________________ ______________________________________________________________________________ 4 Site Access and Haul Routes The primary route for this project will be from the City’s Water Pollution Control Facility (WPCF) to the Project location using the following roads: • 4th Street SE to State Route 529 to I-5; • I-5 south to 41st Street, south on the Larimer Road; • East on the Lowell-Snohomish River Road to the project site. Alternate routes with COE approval can be used if road or traffic conditions are not favorable along the primary route (ice, severe fog, road construction, etc.). Fertilizer Considerations Soils provide the 17 elements known to be essential for plant growth. The addition of biosolids to soils can provide sufficient nitrogen and potassium for crop growth. Other essential macro- and micronutrients are provided by biosolid application, such as sulfur, phosphorus, and zinc, however crops may need supplementary fertilizers to provide minimum nutrients. Additional nitrogen will not be added without Ecology approval. The appropriate biosolids application rate can be calculated by determining existing soil conditions, identifying crop needs and the fertilizer value of the biosolids. Biosolids Application Rates Application rates are calculated by determining annual nitrogen requirement of the proposed crops, biosolids nutrient characteristics, annual nitrogen inputs from nitrogen volatilization rates, mineralization rates, soil nitrogen content, and soil nitrogen storage capacity. Biosolids application rates will be calculated using methods described in “Managing Nitrogen from Biosolids” (Washington State Department of Ecology Publication #99-508) or other tools provided by Ecology. Biosolids applications are made for a variety of purposes including fertilization and improvement of soil physical properties related to moisture infiltration and retention. Field applications of biosolids will be checked against the target application rate. The actual tons applied will be compared to the target rate. Adjustments to equipment will be made to meet the target rate as closely as possible. Given the type of application and the nature of the material, operations strive for an accuracy of the target rate of plus or minus 15%. Site Operation The following describes how biosolids are transported, stored, and handled on-site, including application, buffer areas, operations and environmental monitoring, approximate application schedules, and contingency plans. Transportation Biosolids will be transported in trucks, pups, containers, or in end dump trailers. Additional procedures for transportation are covered under the “Spill Prevention and Response Plan” (Appendix E).