Washington State Dept. of Ecology 3/27/2025

City of Everett, Public Works Department, Water Pollution Control Facility Page 8 of 13 Land Application Site Management - Marshland City of Everett biosolids that are land applied meet the Class B Pathogen Reduction Requirements in WAC 173-308-170 and the Table 3 Pollutant Concentration Limits in WAC 173-808-160. To preserve the lifetime of the City owned application site, biosolids with pollutant concentrations that would require recording cumulative loading to the site will be landfilled in a Subtitle D facility. The Marshland site is owned by the City of Everett and leased to Snohomish Valley Farms (SVF) for the purpose of land application of Everett’s Class B biosolids. SVF, along with other beneficial use facilities in the region, bid on the hauling and land application of Everett’s biosolids. If Marshland cannot take the dredged biosolids for any reason, or is not lowest bidder, then Everett’s biosolids are applied to other beneficial use facilities. The City of Everett and SVF’s work together to prepare a bid document and SSLAP through the process described below. The City takes soil samples each spring and after crop cutting in the years biosolids are applied. Samples measure nitrate, nitrite, ammonia, TKN, and pH in the soil. For sampling methods, see the specific Marshland Soil Sampling and Analysis Plan. The amount of biosolids that can be applied depend on the nutrient concentrations in the dewatered biosolids and a site-specific agronomic rate based off the planned crop and site conditions. Marshland is divided into the East Field and the West Field by the Marshland Canal. Each field is sampled separately and may be planted with different crops with different agronomic rates. As part of the biosolids hauling and land application bid, each bidder is required to submit a SSLAP for their proposed site. The low bidder submits and obtains approval directly for application onto their site by the Ecology Regional Biosolids Coordinator. Any remaining biosolids over the calculated and approved application amount as permitted by Ecology go to the next lowest bidder and their proposed site. Marshland spring soil sampling is scheduled annually in March/April to track and determine appropriate application rates for the East and West Fields. Sampling is scheduled in March/April to allow the site to dry from wet weather conditions and to be representative of the soil at the time of application. Sampling methods require the water table to be lower than a foot down, so any sample site that is not sampled due to high water table is marked and recorded. The Department of Ecology requires soil samples to be taken after crop cutting after a season of application of biosolids to monitor the crop uptake of nutrients. A second round of soil sampling will be scheduled by the COE Biosolids Manager on each field once crop cutting has been completed by Snohomish Valley Farms, typically in September or October.