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.

PDFWAC 173-308-900

Appendix A—Procedure to determine the annual whole biosolids application rate.