21.9 A900 - Compost
This section provides the compost specifications specific to BMPs throughout the SWMM and is arranged in a table format for ease of use. Refer to the specific BMP for all other design and material specifications
Meet the definition for “composted material” per WAC 173-350-100 and comply with standards in WAC 173-350-220, except the feedstock may contain biosolids or manure feedstocks. Have no visible water or dust during handling. Have soil organic matter content of 40% to 65%. Have a carbon to nitrogen ratio below 25:1. Carbon to nitrogen ratio may be as high as 35:1 for plantings composed entirely of plants native to the Puget Sound Lowlands region. City of Tacoma TAGRO Potting Soil Mix may be used as an alternative to the compost component. Meet the definition for “composted material” per WAC 173-350-100 and comply with standards in WAC 173-350-220, except the feedstock may contain biosolids or manure feedstocks. Be coarse compost meeting the following size gradations (by dry weight) when tested in accordance with the U.S. Composting Council “Test Methods for the Examination of Compost and Composting” (TMECC) Test Method 02.02-B. Have no visible water or dust during handling Have soil organic matter content of 40% to 65%. Have a carbon to nitrogen ratio below 25:1. Carbon to nitrogen ratio may be as high as 35:1 for plantings composed entirely of plants native to the Puget Sound Lowlands region. Meet the definition for “composted material” per WAC 173-350-100 and comply with standards in WAC 173-350-220, except the feedstock may contain biosolids or manure feedstocks. Have no visible water or dust during handling. Have soil organic matter content of 40% to 65%. Have a carbon to nitrogen ratio below 25:1. Carbon to nitrogen ratio may be as high as 35:1 for plantings composed entirely of plants native to the Puget Sound Lowlands region. City of Tacoma TAGRO Potting Soil Mix may be used as an alternative to the compost component. Meet the definition for “composted material” per WAC 173-350-100 and comply with standards in WAC 173-350-220, except the feedstock may contain biosolids or manure feedstocks. Be coarse compost meeting the following size gradations (by dry weight) when tested in accordance with the U.S. Composting Council “Test Methods for the Examination of Compost and Composting” (TMECC) Test Method 02.02-B. Have no visible water or dust during handling. Have soil organic matter content of 40% to 65%. Have a carbon to nitrogen ratio below 25:1. Carbon to nitrogen ratio may be as high as 35:1 for plantings composed entirely of plants native to the Puget Sound Lowlands region. City of Tacoma TAGRO Potting Soil Mix may be used as an alternative to the compost component. Meet the definition for “composted material” per WAC 173-350-100 and comply with standards in WAC 173-350-220, except the feedstock may contain biosolids or manure feedstocks. Have no visible water or dust during handling. Have soil organic matter content of 40% to 65%. Have a carbon to nitrogen ratio below 25:1. Carbon to nitrogen ratio may be as high as 35:1 for plantings composed entirely of plants native to the Puget Sound Lowlands region. City of Tacoma TAGRO Potting Soil Mix may be used as an alternative to the compost component. Meet the definition for “composted material” per WAC 173-350-100 and comply with standards in WAC 173-350-220, except the feedstock may contain biosolids or manure feedstocks. Be coarse compost meeting the following size gradations (by dry weight) when tested in accordance with the U.S. Composting Council “Test Methods for the Examination of Compost and Composting” (TMECC) Test Method 02.02-B. Have no visible water or dust during handling. Have soil organic matter content of 40% to 65%. Have a carbon to nitrogen ratio below 25:1. Carbon to nitrogen ratio may be as high as 35:1 for plantings composed entirely of plants native to the Puget Sound Lowlands region. City of Tacoma TAGRO Potting Soil Mix may be used as an alternative to the compost component. Meet the definition for “composted material” per WAC 173-350-100 and comply with standards in WAC 173-350-220, except the feedstock may contain biosolids or manure feedstocks. Be coarse compost meeting the following size gradations (by dry weight) when tested in accordance with the U.S. Composting Council “Test Methods for the Examination of Compost and Composting” (TMECC) Test Method 02.02-B Have no visible water or dust during handling. Have soil organic matter content of 40% to 65%. Have a carbon to nitrogen ratio below 25:1. Carbon to nitrogen ratio may be as high as 35:1 for plantings composed entirely of plants native to the Puget Sound Lowlands region City of Tacoma TAGRO Potting Soil Mix may be used as an alternative to the compost component. Compost used to meet the organic content requirements shall meet the following standards: Meet the definition of “composted material” in WAC 173-350-100 and complies with testing parameters and other standards in WAC 173-350-220. Produced at a permitted composting facility. Permitted compost facilities in Washington are included on a list available at: https://ecology.wa.gov/Waste-Toxics/Reducing-recycling-waste/Organic-materials/Managing-organics-compost The compost product must originate from a feedstock that contains a minimum of 65% by volume recycled plant waste comprised of “yard debris,” “crop residues,” and “bulking agents”. A maximum of 35% by volume of "post-consumer food waste" may be substituted for recycled plant waste. Compost may have up to 35% biosolids or manure. Terms are defined in WAC 173-350-100. Stable (low oxygen use and CO2 generation) and mature (capable of supporting plant growth) by tests shown below. This is critical to plant success in a bioretention soil mix. Moisture content range: no visible free water or dust produced when handling the material. Tested in accordance with U.S. Composting Council “Test Method for the Examination of Compost and Composting” (TMECC), as established in the Composting Council’s “Seal of Testing Assurance” (STA) program. Most Washington compost facilities now use these tests. Be fine compost meeting the following size gradation (by dry weight) when tested in accordance with TMECC test method 02.02-B, “Sample Sieving for Aggregate Size Classification.” pH between 6.0 and 8.5 (TMECC 04.11-A). “Physical contaminants” (as defined in WAC 173-350-100) content less than 1% by weight (TMECC 03.08-A) total, not to exceed 0.25 percent film plastic by dry weight. Minimum organic matter content of 40% and maximum organic matter content of 65% (TMECC 05.07-A “Loss on Ignition”) Soluble salt content less than 4.0 dS/m (mmhos/cm) (TMECC 04.10-A “Electrical Conductivity, 1.5 Slurry Method, Mass Basis”) Maturity indicators from a cucumber bioassay (TMEC 05.05-A “Seedling Emergence and Relative Growth”) must be greater than 80% for both emergence and vigor Stability of 7 mg CO2-C/g OM/day or below (TMECC 05.08-B “Carbon Dioxide Evolution Rate”) Carbon to nitrogen ratio (TMECC 05.02A “Carbon to Nitrogen Ratio” which uses 04.01 “Organic Carbon” and 04.02D “Total Nitrogen by Oxidation”) of less than 25:1. The C:N ratio may be up to 35:1 for planting composed entirely of Puget Sound Lowland native species. BMP L601 - Rain Gardens (as a component of rain garden oil mix) Meet the definition of “composted material” in WAC 173-350-100 and complies with testing parameters and other standards in WAC 173-350-220. Be Fine Compost meeting the following size gradation (by dry weight) when tested in accordance with TMECC test method 02.02-B, “Sample Sieving for Aggregate Size Classification.” BMP L630 - Bioretention (compost used as a component of bioretention soil mix) Meets the definition of “composted material” in WAC 173-350-100 and complies with testing parameters and other standards in WAC 173-350-220. Produced at a permitted composting facility. Permitted compost facilities in Washington are included on a list available at: https://ecology.wa.gov/Waste-Toxics/Reducing-recycling-waste/Organic-materials/Managing-organics-compost The compost product must originate from a feedstock that contains a minimum of 65% by volume recycled plant waste comprised of “yard debris,” “crop residues,” and “bulking agents”. A maximum of 35% by volume of "post-consumer food waste" may be substituted for recycled plant waste. Biosolids and/or manure are not allowed. Terms are defined in WAC 173-350-100. Stable (low oxygen use and CO2 generation) and mature (capable of supporting plant growth) by tests shown below. This is critical to plant success in a bioretention soil mix. Moisture content range: no visible free water or dust produced when handling the material. Tested in accordance with U.S. Composting Council “Test Method for the Examination of Compost and Composting” (TMECC), as established in the Composting Council’s “Seal of Testing Assurance” (STA) program. Most Washington compost facilities now use these tests. Be fine compost meeting the following size gradation (by dry weight) when tested in accordance with TMECC test method 02.02-B, “Sample Sieving for Aggregate Size Classification.”. pH between 6.0 and 8.5 (TMECC 04.11-A). “Physical contaminants” (as defined in WAC 173-350-100) content less than 1% by weight (TMECC 03.08-A) total, not to exceed 0.25 percent film plastic by dry weight. Minimum organic matter content of 40% (TMECC 05.07-A “Loss on Ignition”) Soluable salt content less than 4.0 dS/m (mmhos/cm) (TMECC 04.10-A “Electrical Conductivity, 1.5 Slurry Method, Mass Basis”) Maturity indicators from a cucumber bioassay (TMEC 05.05-A “Seedling Emergence and Relative Growth”) must be greater than 80% for both emergence and vigor Stability of 7 mg CO2-C/g OM/day or below (TMECC 05.08-B “Carbon Dioxide Evolution Rate”) Carbon to nitrogen ratio (TMECC 05.02A “Carbon to Nitrogen Ratio” which uses 04.01 “Organic Carbon” and 04.02D “Total Nitrogen by Oxidation”) of less than 25:1. The C:N ratio may be up to 35:1 for planting composed entirely of Puget Sound Lowland native species and up to 40:1 for coarse compost to be used as a surface mulch (not in a soil mix). BMP L630 - Bioretention (compost used as mulch layer) Compost used as the mulch layer in the bioretention facility shall conform to WSDOT Standard Specification 9-14.5(8) - Compost using the medium compost gradation. Meet the definition for “composted material” per WAC 173-350-100 and comply with standards in WAC 173-350-220, except the feedstock may contain biosolids or manure feedstocks. Have no visible water or dust during handling. Have soil organic matter content of 40% to 65%. Have a carbon to nitrogen ratio below 25:1. Carbon to nitrogen ratio may be as high as 35:1 for plantings composed entirely of plants native to the Puget Sound Lowlands region. Meet the definition for “composted material” per WAC 173-350-100 and comply with standards in WAC 173-350-220, except the feedstock may contain biosolids or manure feedstocks. Have no visible water or dust during handling. Have soil organic matter content of 40% to 65%. Have a carbon to nitrogen ratio below 25:1. Carbon to nitrogen ratio may be as high as 35:1 for plantings composed entirely of plants native to the Puget Sound Lowlands region. Meet the definition for “composted material” per WAC 173-350-100 and comply with standards in WAC 173-350-220, except the feedstock may contain biosolids or manure feedstocks. Have no visible water or dust during handling. Have soil organic matter content of 40% to 65%. Have a carbon to nitrogen ratio below 25:1. Carbon to nitrogen ratio may be as high as 35:1 for plantings composed entirely of plants native to the Puget Sound Lowlands region. Meet the definition for “composted material” per WAC 173-350-100 and comply with standards in WAC 173-350-220. Have no visible water or dust during handling. Have soil organic matter content of 40% to 65%. Have a carbon to nitrogen ratio below 25:1. Carbon to nitrogen ratio may be as high as 35:1 for plantings composed entirely of plants native to the Puget Sound Lowlands region. Compost shall meet the specifications below: Meets the definition of “composted material” in WAC 173-350-100 and complies with testing parameters and other standards in WAC 173-350-220. Be produced at a permitted composting facility. Permitted compost facilities in Washington are included on a list available at https://ecology.wa.gov/Waste-Toxics/Reducing-recycling-waste/Organic-materials/Managing-organics-compost. The compost product must originate from a feedstock that contains a minimum of 65% by volume recycled plant waste comprised of “yard debris,” “crop residues,” and “bulking agents”. A maximum of 35% by volume of "post-consumer food waste" may be substituted for recycled plant waste. Biosolids and/or manure are not allowed. Terms are defined in WAC 173-350-100. Stable (low oxygen use and CO2 generation) and mature (capable of supporting plant growth) by tests shown below. This is critical to plant success. Moisture content range: no visible free water or dust produced when handling the material. Tested in accordance with U.S. Composting Council “Test Method for the Examination of Compost and Composting” (TMECC), as established in the Composting Council’s “Seal of Testing Assurance” (STA) program. Most Washington compost facilities now use these tests. Be fine compost meeting the following size gradation (by dry weight) when tested in accordance with TMECC test method 02.02-B, “Sample Sieving for Aggregate Size Classification.” pH between 6.0 and 8.5 (TMECC 04.11-A). “Physical contaminants” (as defined in WAC 173-350-100) content less than 1% by weight (TMECC 03.08-A) total, not to exceed 0.25 percent film plastic by dry weight. Minimum organic matter content of 40% (TMECC 05.07-A “Loss on Ignition”) Soluble salt content less than 4.0 dS/m (mmhos/cm) (TMECC 04.10-A “Electrical Conductivity, 1.5 Slurry Method, Mass Basis”) Maturity indicators from a cucumber bioassay (TMEC 05.05-A “Seedling Emergence and Relative Growth”) must be greater than 80% for both emergence and vigor Stability of 7 mg CO2-C/g OM/day or below (TMECC 05.08-B “Carbon Dioxide Evolution Rate”) Carbon to nitrogen ratio (TMECC 05.02A “Carbon to Nitrogen Ratio” which uses 04.01 “Organic Carbon” and 04.02D “Total Nitrogen by Oxidation”) of less than 25:1. The C:N ratio may be up to 35:1 for planting composed entirely of Puget Sound Lowland native species. Lowland native species and up to 40:1 for coarse compost to be used as a surface mulch (not in a soil mix). Meet the definition for “composted material” per WAC 173-350-100 and comply with standards in WAC 173-350-220.
