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 4 - Pathogens and Vector Attraction Reduction › Section 9VAC25-31-710 - Pathogens

Current through Register Vol. 40, No. 24, July 15, 2024
A.
					 Biosolids - Class A.
1. The requirement in
					 subdivision 2 of this subsection and the requirements in either subdivisions 3,
					 4, 5, 6, 7, or 8 of this subsection shall be met for a biosolids to be
					 classified Class A with respect to pathogens.
2. The Class A pathogen requirements in
					 subdivisions 3 through 8 of this subsection shall be met either prior to
					 meeting or at the same time the vector attraction reduction requirements in
					 9VAC25-31-720,
					 except the vector attraction reduction requirements in
					 9VAC25-31-720
					 B 6 through B 8, are met.
3. Class
					 A - Alternative 1.
a. Either the density of
					 fecal coliform in the biosolids shall be less than 1,000 Most Probable Number
					 per gram of total solids (dry weight basis), or the density of Salmonella sp.
					 bacteria in the biosolids shall be less than three Most Probable Number per
					 four grams of total solids (dry weight basis) at the time the biosolids is used
					 or disposed; at the time the biosolids is prepared for sale or give away in a
					 bag or other container for application to the land; or at the time the
					 biosolids or material derived from biosolids is prepared to meet the
					 requirements in
					 9VAC25-31-510
					 B, C, E, or F.
b. The temperature
					 of the sewage sludge that is used or disposed shall be maintained at a specific
					 value for a period of time.
(1) When the
					 percent solids of the sewage sludge is 7.0% or higher, the temperature of the
					 sewage sludge shall be 50°C or higher; the time period shall be 20 minutes
					 or longer; and the temperature and time period shall be determined using
					 equation (1), except when small particles of sewage sludge are heated by either
					 warmed gases or an immiscible liquid.
EQUATION (1)
D =
								  131,700,000/100.1400t
D = time in days
t = temperature in degrees Celsius
(2) When the percent solids of the sewage
					 sludge is 7.0% or higher and small particles of sewage sludge are heated by
					 either warmed gases or an immiscible liquid, the temperature of the sewage
					 sludge shall be 50°C or higher; the time period shall be 15 seconds or
					 longer; and the temperature and time period shall be determined using equation
					 (1).
(3) When the percent solids of
					 the sewage sludge is less than 7.0% and the time period is at least 15 seconds,
					 but less than 30 minutes, the temperature and time period shall be determined
					 using equation (1).
(4) When the
					 percent solids of the sewage sludge is less than 7.0%; the temperature of the
					 sewage sludge is 50°C or higher; and the time period is 30 minutes or
					 longer, the temperature and time period shall be determined using equation (2).
EQUATION (2)
D =
								  50,070,000/100.1400t
D = time in days
t = temperature in degrees Celsius
4. Class A - Alternative 2.
a. Either the density of fecal coliform in
					 the biosolids shall be less than 1,000 Most Probable Number per gram of total
					 solids (dry weight basis), or the density of Salmonella sp. bacteria in the
					 biosolids shall be less than three Most Probable Number per four grams of total
					 solids (dry weight basis) at the time the biosolids is used or disposed; at the
					 time the biosolids is prepared for sale or give away in a bag or other
					 container for application to the land; or at the time the biosolids or material
					 derived from biosolids is prepared to meet the requirements in
					 9VAC25-31-510
					 B, C, E, or F.
b.
(1) The pH of the sewage sludge that is used
					 or disposed shall be raised to above 12 and shall remain above 12 for 72
					 hours.
(2) The temperature of the
					 sewage sludge shall be above 52°C for 12 hours or longer during the period
					 that the pH of the sewage sludge is above 12.
(3) At the end of the 72-hour period during
					 which the pH of the sewage sludge is above 12, the sewage sludge shall be air
					 dried to achieve a percent solids in the sewage sludge greater than
					 50%.
5. Class
					 A - Alternative 3.
a. Either the density of
					 fecal coliform in the biosolids shall be less than 1,000 Most Probable Number
					 per gram of total solids (dry weight basis), or the density of Salmonella sp.
					 bacteria in biosolids shall be less than three Most Probable Number per four
					 grams of total solids (dry weight basis) at the time the biosolids is used or
					 disposed; at the time the biosolids is prepared for sale or give away in a bag
					 or other container for application to the land; or at the time the biosolids or
					 material derived from biosolids is prepared to meet the requirements in
					 9VAC25-31-510
					 B, C, E, or F.
b.
(1) The sewage sludge shall be analyzed prior
					 to pathogen treatment to determine whether the sewage sludge contains enteric
					 viruses.
(2) When the density of
					 enteric viruses in the sewage sludge prior to pathogen treatment is less than
					 one Plaque-forming Unit per four grams of total solids (dry weight basis), the
					 sewage sludge is Class A with respect to enteric viruses until the next
					 monitoring episode for the sewage sludge.
(3) When the density of enteric viruses in
					 the sewage sludge prior to pathogen treatment is equal to or greater than one
					 Plaque-forming Unit per four grams of total solids (dry weight basis), the
					 sewage sludge is Class A with respect to enteric viruses when the density of
					 enteric viruses in the sewage sludge after pathogen treatment is less than one
					 Plaque-forming Unit per four grams of total solids (dry weight basis) and when
					 the values or ranges of values for the operating parameters for the pathogen
					 treatment process that produces the sewage sludge that meets the enteric virus
					 density requirement are documented.
(4) After the enteric virus reduction in
					 subdivision 5 b (3) of this subsection is demonstrated for the pathogen
					 treatment process, the sewage sludge continues to be Class A with respect to
					 enteric viruses when the values for the pathogen treatment process operating
					 parameters are consistent with the values or ranges of values documented in
					 subdivision 5 b (3) of this subsection.
c.
(1) The
					 sewage sludge shall be analyzed prior to pathogen treatment to determine
					 whether the sewage sludge contains viable helminth ova.
(2) When the density of viable helminth ova
					 in the sewage sludge prior to pathogen treatment is less than one per four
					 grams of total solids (dry weight basis), the sewage sludge is Class A with
					 respect to viable helminth ova until the next monitoring episode for the sewage
					 sludge.
(3) When the density of
					 viable helminth ova in the sewage sludge prior to pathogen treatment is equal
					 to or greater than one per four grams of total solids (dry weight basis), the
					 sewage sludge is Class A with respect to viable helminth ova when the density
					 of viable helminth ova in the sewage sludge after pathogen treatment is less
					 than one per four grams of total solids (dry weight basis) and when the values
					 or ranges of values for the operating parameters for the pathogen treatment
					 process that produces the sewage sludge that meets the viable helminth ova
					 density requirement are documented.
(4) After the viable helminth ova reduction
					 in subdivision 5 c (3) of this subsection is demonstrated for the pathogen
					 treatment process, the sewage sludge continues to be Class A with respect to
					 viable helminth ova when the values for the pathogen treatment process
					 operating parameters are consistent with the values or ranges of values
					 documented in subdivision 5 c (3) of this subsection.
6. Class A - Alternative 4.
a. Either the density of fecal coliform in
					 the biosolids shall be less than 1,000 Most Probable Number per gram of total
					 solids (dry weight basis), or the density of Salmonella sp. bacteria in the
					 biosolids shall be less than three Most Probable Number per four grams of total
					 solids (dry weight basis) at the time the biosolids is used or disposed; at the
					 time the biosolids is prepared for sale or give away in a bag or other
					 container for application to the land; or at the time the biosolids or material
					 derived from biosolids is prepared to meet the requirements in
					 9VAC25-31-510
					 B, C, E, or F.
b. The density of
					 enteric viruses in the biosolids shall be less than one Plaque-forming Unit per
					 four grams of total solids (dry weight basis) at the time the biosolids is used
					 or disposed; at the time the biosolids is prepared for sale or give away in a
					 bag or other container for application to the land; or at the time the
					 biosolids or material derived from biosolids is prepared to meet the
					 requirements in
					 9VAC25-31-510
					 B, C, E, or F, unless otherwise specified by the department.
c. The density of viable helminth ova in the
					 biosolids shall be less than one per four grams of total solids (dry weight
					 basis) at the time the biosolids is used or disposed; at the time the biosolids
					 is prepared for sale or give away in a bag or other container for application
					 to the land; or at the time the biosolids or material derived from biosolids is
					 prepared to meet the requirements in
					 9VAC25-31-510
					 B, C, E, or F unless otherwise specified by the department.
7. Class A - Alternative 5.
a. Either the density of fecal coliform in
					 the biosolids shall be less than 1,000 Most Probable Number per gram of total
					 solids (dry weight basis), or the density of Salmonella, sp. bacteria in the
					 biosolids shall be less than three Most Probable Number per four grams of total
					 solids (dry weight basis) at the time the biosolids is used or disposed; at the
					 time the biosolids is prepared for sale or give away in a bag or other
					 container for application to the land; or at the time the biosolids or material
					 derived from biosolids is prepared to meet the requirements in
					 9VAC25-31-510
					 B, C, E, or F.
b. Biosolids that is
					 used or disposed shall be treated in one of the processes to further reduce
					 pathogens described in subsection E of this section.
8. Class A - Alternative 6.
a. Either the density of fecal coliform in
					 the biosolids shall be less than 1,000 Most Probable Number per gram of total
					 solids (dry weight basis), or the density of Salmonella, sp. bacteria in the
					 biosolids shall be less than three Most Probable Number per four grams of total
					 solids (dry weight basis) at the time the biosolids is used or disposed; at the
					 time the biosolids is prepared for sale or give away in a bag or other
					 container for application to the land; or at the time the biosolids or material
					 derived from biosolids is prepared to meet the requirements in
					 9VAC25-31-510
					 B, C, E, or F.
b. Biosolids that is
					 used or disposed shall be treated in a process that is equivalent to a process
					 to further reduce pathogens, as determined by the department.