ARM 17.50.1716. SAMPLING AND ANALYSIS REQUIREMENTS FOR COMPOST FACILITIES

(1) For purposes of this subchapter, the department adopts and incorporates by reference: (a) The United States Department of Agriculture Natural Resources Conservation Service Montana Operation and Maintenance Guide for Composting Facility (MT EFH, 4/14) available at https://www.nrcs.usda.gov/wps/portal/nrcs/site/mt/home/ or by contacting NRCS Montana USDA Natural Resources Conservation Service, 10 East Babcock Street, Room 443, Bozeman, MT 59715-4704 or 1 (406) 587-6811; and (b) US EPA Class A standard, 40 CFR 503.13, Table 2 which may be obtained at https://www.gpo.gov/fdsys/granule/CFR-2010-title40-vol29/CFR-2010-title40-vol29-sec503-13 or by contacting the National Technical Information Service, 5301 Shawnee Road, Alexandria, VA 22312 or 1 (800) 553-6847. (2) The owner or operator of a licensed compost facility must sample and analyze compost material based on the size and frequency requirements in Table 3, and verify that the finished compost meets the minimum standards established in Table 4:A through 4:E based on the type of licensed compost facility. (3) Sampling procedures must be described in the facility's operation and maintenance plan and produce valid and representative analytical results. (4) The following requirements apply to finished compost: (a) minor compost facilities – Table 4:D; (b) animal mortality compost facilities – Table 4:C through 4:E; (c) major compost facilities – Table 4:A through 4:E; and (d) facilities composting biosolids – Table 4:A through 4:E. (5) The department may require sampling and analysis of additional constituents as determined to be necessary to protect human health and the environment. (6) When finished compost exceeds the applicable minimum standards identified in Table 4:A through 4:E based on the facility type, the owner or operator shall: (a) reintroduce the material back into the active composting process; (b) dispose of the material at a licensed Class II solid waste management facility; or (c) otherwise use the material in a manner approved by the department. Table 3: TESTING FREQUENCY FOR COMPOST FACILITIES Finished Compost Frequency Less than 5,000 cubic yards annually 5,000 – 10,000 cubic yards semiannually 10,000 + cubic yards quarterly Table 4:A TEMPERATURE • High temperatures (133°F for 3 days minimum) are required to destroy pathogenic microbes • High temperatures (>145°F) are required to destroy weed seeds/plants • Temperatures that are too high (>160°F) shall require turning or other incorporation of air. If the pile gets too hot it will shut down (if moist and hot) and or combust Table 4:B MAXIMUM CONSTITUENT CONCENTRATION FOR COMPOST SOLD OR DISTRIBUTED FOR OFFSITE USE HEAVY METALS Parameter Unit Limit Test Method found in EPA's SW-846 Arsenic mg/kg 41 EPA dry wt. 6010A or 7061A; or EPA 3050 and 6010A or 7061A Cadmium mg/kg 39 AOAC 975.03B(b) and EPA dry wt. 6010A or 7130; or EPA 3050 and 6010A or 7130 Chromium mg/kg 1200 EPA dry wt. 6010A or 7190; or EPA 3050 and 6010A or 7190 Copper mg/kg dry wt 1500 EPA 6010A or 7210; or EPA 3050 and 6010A or 7210 Lead mg/kg dry wt 300 EPA 6010A or 7420 or 7421; or EPA 3050 and 6010A or 7420 or 7421 Mercury mg/kg dry wt 17 EPA 7471A Molybdenum mg/kg dry wt 54 EPA 6010A or 7480 or 7481; or EPA 6010A or 7480 or 7481; or EPA 3050 and 6010A or 7480 or 7481. Nickel mg/kg dry wt 420 EPA 6010A or 7520; or EPA 3050 and 6010A or 7520 Selenium mg/kg dry wt 100 EPA 7740 or 7741A; or EPA 3050 and 7740 or 7741A Zinc mg/kg dry wt 2800 EPA 6010A or 7950; or EPA 3050 and EPA 6010A or 7950 Table 4:C PATHOGENS • The owner or operator of a compost operation shall ensure that: • the density of the fecal coliform present in the compost is less than 1,000 most probable number (mpn) per gram of total solids (dry weight basis); or • the density of Salmonella species bacteria in the compost is less than three mpn per four grams of total solids (dry weight basis) at the time the compost is to be sold or otherwise distributed for use. • Upon request of the department the licensee shall test any other disease agents determined by the source of animal mortality. Table 4:D COMPOST PROPERTIES Parameter Units Potting Grade1/ Mulch/Top Dressing2/ Soil Amendment3/ pH pH units 6-8.5 5.5-9.0 6-8.5 Moisture content %, wet weight basis 30-60 30-60 30-60 Organic Matter Content %, dry weight basis 30-65 >than 30 30-65 Soluble Salt Concentration dS/m (mmhos/cm) <6 <10 <10 Particle Size % passing a selected mesh size, dry weight basis 99%<1/2" 99% <3" 25%+| <3/8" 99% <3/4" Physical Contaminants (inert material) %, dry weight basis <1 <1 <1 Stability Indicator CO 2 Evolution Rate mg CO 2 -C per g OM per day <8 <8 <8 Nutrient content (total N, P2O5, K2O, Ca, Mg) %, dry weight No limit, just informational. No limit, just informational. No limit, just informational. 1/ Potting Grade: Compost used within a blend of materials to formulate a potting mix or seed bed. Compost should not exceed 20-30% of the mix. Soluble Salt content of the mix should not exceed 2.5 dS/cm to 4 dS/cm depending on the plants to be grown. 2/ Mulch/Top Dressing: Compost is applied to the soil surface to help inhibit weed growth, conserve soil moisture, and reduce soil erosion. Compost is typically applied at a 1-2 inch thickness. Contact with tree trunks or plant stems should be avoided. 3/ Soil Amendment: Compost is incorporated into the soil to improve soil quality (organic matter, water-holding capacity, aeration, drainage, and cation exchange capacity). Typical blends for soil amendment use is one part compost to two parts soil. Table 4:E RESIDUAL HERBICIDES Parameter Units Potting Grade1/ Mulch/Top Dressing2/ Soil Amendment3/ Maturity Indicator (bioassay) Seed Emergence Seedling Vigor %, relative to positive control %, relative to positive control Minimum 80 Minimum 80 Minimum 80 Minimum 80 Minimum 80 Minimum 80 (7) Compost that contains sewage sludge or septage must meet the requirements in 40 CFR part 503 Appendix B – Pathogen Treatment Process (58 FR 9387, Feb. 19, 1993, as amended at 64 FR 42573, Aug. 4, 1999).