Administrative Rules of Montana
Department 17 - ENVIRONMENTAL QUALITY
Chapter 17.50 - SOLID WASTE MANAGEMENT
Subchapter 17.50.17 - Compost License and Operation Standards
Rule 17.50.1716 - SAMPLING AND ANALYSIS REQUIREMENTS FOR COMPOST FACILITIES
Current through Register Vol. 18, September 20, 2024
(1) For purposes of this subchapter, the department adopts and incorporates by reference:
(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:
(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:
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; and
* 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 CO2 Evolution Rate |
mg CO2 -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).
AUTH: 75-10-204, MCA;IMP: 75-10-204, MCA
