PDFWAC 173-308-900
Appendix A—Procedure to determine the annual whole biosolids application rate.
When biosolids are sold or given away in a bag or other container for application to the land, and any of the pollutant concentration limits in Table 3 of WAC 173-308-160 are exceeded, the mathematical product of the concentration in the biosolids of each pollutant listed in Table 4 of WAC 173-308-160 and the annual whole biosolids application rate (AWBAR) must not cause the annual pollutant loading rate for the pollutant in Table 4 of WAC 173-308-160 to be exceeded. This appendix contains the procedure used to determine an AWBAR that does not cause the annual pollutant loading rates in Table 4 of WAC 173-308-160 to be exceeded. The relationship between the annual pollutant loading rate (APLR) for a pollutant and the annual whole biosolids application rate (AWBAR) is shown in equation (7).
Equation (7) | ||
APLR = C* AWBAR* 0.001 | ||
Where: | ||
APLR = Annual pollutant loading rate in kilograms per hectare per 365 day period. | ||
C = Pollutant concentration in milligrams, per kilogram of total solids (dry weight basis). | ||
AWBAR = Annual whole biosolids application rate in metric tons per hectare per 365 day period (dry weight basis). | ||
0.001 = A conversion factor. | ||
To determine the AWBAR, equation (7) is rearranged into equation (8): | ||
Equation (8) | ||||
AWBAR | = | APLR | ||
C* 0.001 | ||||
The procedure used to determine the AWBAR is presented below.
Procedure:
1. Analyze a sample of the biosolids to determine the concentration for each of the pollutants listed in Table 4 of WAC 173-308-160.
2. Using the pollutant concentrations from Step 1 and the APLRs from Table 4 of WAC 173-308-160, calculate an AWBAR for each pollutant using equation (8).
3. The correct AWBAR is the lowest AWBAR calculated in Step 2.
[Statutory Authority: RCW 70.95J.020 and 70.95.255. WSR 98-05-101 (Order 97-30), § 173-308-900, filed 2/18/98, effective 3/21/98.]