Virginia Administrative Code
Title 9 - ENVIRONMENT
Agency 25 - STATE WATER CONTROL BOARD
Chapter 31 - VIRGINIA POLLUTANT DISCHARGE ELIMINATION SYSTEM (VPDES) PERMIT REGULATION
Part VI - Standards for the Use of Biosolids or Disposal of Sewage Sludge
Article 2 - Biosolids Applied to the Land
Section 9VAC25-31-540 - Pollutant limits
Universal Citation: 9 VA Admin Code 9VAC25-31-540
Current through Register Vol. 41, No. 3, September 23, 2024
A. Biosolids.
1. Bulk biosolids or biosolids sold or given
away in a bag or other container shall not be applied to the land if the
concentration of any pollutant in the biosolids exceeds the ceiling
concentration for the pollutant in Table 1 of this section.
2. If bulk biosolids is applied to
agricultural land, forest, a public contact site, or a reclamation site,
either:
a. The cumulative loading rate for
each pollutant shall not exceed the cumulative pollutant loading rate for the
pollutant in Table 2 of this section; or
b. The concentration of each pollutant in the
biosolids shall not exceed the concentration for the pollutant in Table 3 of
this section.
3. If bulk
biosolids is applied to a lawn or a home garden, the concentration of each
pollutant in the biosolids shall not exceed the concentration for the pollutant
in Table 3 of this section.
4. If
biosolids is sold or given away in a bag or other container for application to
the land, either:
a. The concentration of
each pollutant in the biosolids shall not exceed the concentration for the
pollutant in Table 3 of this section; or
b. The product of the concentration of each
pollutant in the biosolids and the annual whole sludge application rate for the
biosolids shall not cause the annual pollutant loading rate for the pollutant
in Table 4 of this section to be exceeded. The procedure used to determine the
annual whole sludge application rate is presented in subsection D of this
section.
B. Pollutant concentrations and loading rates - biosolids.
| TABLE 1 CEILING CONCENTRATIONS | |
| Pollutant | Ceiling Concentration (milligrams per kilogram)* |
| Arsenic | 75 |
| Cadmium | 85 |
| Copper | 4,300 |
| Lead | 840 |
| Mercury | 57 |
| Molybdenum | 75 |
| Nickel | 420 |
| Selenium | 100 |
| Zinc | 7,500 |
| *Dry weight basis | |
| TABLE 2 CUMULATIVE POLLUTANT LOADING RATES(1) | ||
| Pollutant | Cumulative Pollutant Loading Rate | |
| (kilograms per hectare) | (pounds per acre) | |
| Arsenic(2) | 41 | 36 |
| Cadmium | 39 | 35 |
| Copper | 1,500 | 1,340 |
| Lead | 300 | 270 |
| Mercury | 17 | 16 |
| Molybdenum(2) | ||
| Nickel | 420 | 375 |
| Selenium | 100 | 89 |
| Zinc | 2,800 | 2,500 |
| Notes: (1)Such total applications to be made on soils with the biosolids/soil mixture pH adjusted to 6.0 or greater if the biosolids cadmium content is greater than or equal to 21 mg/kg. The maximum cumulative application rate is limited for all ranges of cation exchange capacity due to soil background pH in Virginia of less than 6.5 and lack of regulatory controls of soil pH adjustment after biosolids application ceases. (2)The maximum cumulative application rate is currently under study by the USEPA. Research suggests that for Molybdenum a cumulative pollutant loading rate below 40 kg/hectare may be appropriate to reduce the risk of copper deficiency in grazing animals. | ||
| TABLE 3 POLLUTANT CONCENTRATIONS | |
| Pollutant | Monthly Average Concentration (milligrams per kilogram)* |
| Arsenic | 41 |
| Cadmium | 39 |
| Copper | 1,500 |
| Lead | 300 |
| Mercury | 17 |
| Molybdenum(1) | |
| Nickel | 420 |
| Selenium | 100 |
| Zinc | 2,800 |
| *Dry weight basis Note: (1)The monthly average concentration is currently under study by the USEPA. Research suggests that a monthly average Molybdenum concentration below 40 mg/kg may be appropriate to reduce the risk of copper deficiency in grazing animals. | |
| TABLE 4 ANNUAL POLLUTANT LOADING RATES | ||
| Pollutant | Annual Pollutant Loading Rate(1) (per 365-day period) | |
| (kilograms per hectare) | (pounds per acre) | |
| Arsenic | 2.0 | 1.8 |
| Cadmium | 1.9 | 1.7 |
| Copper | 75 | 67 |
| Lead | 15 | 13 |
| Mercury | 0.85 | 0.76 |
| Molybdenum(2) | ||
| Nickel | 21 | 19 |
| Selenium | 5.0 | 4.6 |
| Zinc | 140 | 125 |
| Notes: (1)Such total applications to be made on soils with the biosolids/soils mixture pH adjusted to 6.0 or greater if the biosolids cadmium content is greater than or equal to 21 mg/kg. The maximum cumulative application rate is limited for all ranges of cation exchange capacity due to soil pH in Virginia of less than 6.5 and lack of regulatory controls of soil pH adjustment after biosolids application ceases. (2)The maximum cumulative application rate is currently under study by the USEPA. | ||
C. Domestic septage. The annual application rate for domestic septage applied to agricultural land, forest, or a reclamation site shall not exceed the annual application rate calculated using equation (1).
| EQUATION (1) |
| AAR = N/0.0026 |
| AAR = Annual application rate in gallons per acre per 365-day period. |
| N = Amount of nitrogen in pounds per acre per 365-day period needed by the crop or vegetation grown on the land. |
D. Procedures to determine the annual whole sludge application rate for biosolids. 9VAC25-31-540 A 4 b requires that the product of the concentration for each pollutant listed in Table 4 of this section in biosolids sold or given away in a bag or other container for application to the land and the AWSAR for the biosolids not cause the annual pollutant loading rate for the pollutant in Table 4 to be exceeded. This section contains the procedure used to determine the AWSAR for a biosolids that does not cause the annual pollutant loading rates in Table 4 of this section to be exceeded.
1. The relationship between the
APLR for a pollutant and the AWSAR for a biosolids is shown in equation (2).
| EQUATION (2) |
| APLR = C x AWSAR x 0.001 |
| 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) |
| AWSAR = Annual whole sludge application rate in metric tons per hectare per 365-day period (dry weight basis) |
| 0.001 = A conversion factor |
2. To determine the AWSAR, equation (2) is
rearranged into equation (3):
| EQUATION (3) |
| AWSAR = APLR/(C x 0.001) |
| AWSAR = Annual whole sludge application rate in metric tons per hectare per 365-day period (dry weight basis) |
| 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) |
| 0.001 = A conversion factor |
3. The procedure used to determine the AWSAR
for a biosolids is presented below.
a.
Analyze a sample of the biosolids to determine the concentration for each of
the pollutants listed in Table 4 of this section in the biosolids.
b. Using the pollutant concentrations from
Step 1 and the APLRs from Table 4 of this section, calculate an AWSAR for each
pollutant using equation (3) above.
c. The AWSAR for the biosolids is the lowest
AWSAR calculated in Step 2.
Statutory Authority
§ 62.1-44.15 of the Code of Virginia.
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