WA ST Dept of Ecology Biosolids 9/8/2022

City of Everett, Public Works Department, Water Pollution Control Facility BIOSOLIDS SAMPLING & ANALYSIS PLAN 8 B) Five samples are from piles or bunkers not already sampled. 3) Sampling for fecal coliforms continues until dredging is complete. 4) If results of fecal coliform sampling result in concentrations equal to or less than the results from in-situ sampling, regrowth is considered to be minimal and sample frequency for Step 2 may be reduced to once every two weeks. Nutrients testing: Dewatered biosolids are tested for nutrients every 200 dry tons (+/-) produced. Dry weight of dewatered biosolids tonnage is calculated on a running basis based on net truck weight and solids content. 1) For nutrient analysis, four samples per 200 dry tons are taken and composited together for analysis. 2) Samples for nutrients may be taken simultaneously with samples for % TS. As part of the dredging and dewatering process, each truckload is sampled for precent total solids (% TS) when it is weighed. Samples are stored according to the test procedure until four samples have been taken. Once % TS sampling complete, the set of four samples are composited and sent to ARI for nutrient analysis. 3) If biosolids are stockpiled before nutrient sampling can occur, the City will follow its sampling SOP for sampling soil piles at its solid waste handling facility. 4. Soil Sampling and Agronomic Rates a. Marshland Soil Sampling 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. Soil samples are taken each Spring and after crop cutting in 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 two fields, the East Field and the West Field by the Marshland Canal. Each field is sampled separately as they may be planted with different crops and have different agronomic rates. The Site Specific Land Application Plan (SSLAP) documents the calculated application rates and application methods for an application site. The Marshland SSLAP is written and submitted to DOE by the City of Everett in coordination with Snohomish Valley Farms. 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 April to track and determine appropriate application rates for the East and West Fields. After a baseline application rate has been determined for