SECTION 312.82. Pathogen Reduction

(a) Class A and Class AB biosolids.

(1) Compliance requirements--Class A and Class AB.

(A) For biosolids to be classified as Class AB, with respect to pathogens, the requirements in subparagraphs (C) and (D) of this paragraph and the requirements of one of the alternatives listed in paragraph (2) of this subsection must be met.

(B) For biosolids to be classified as Class A, with respect to pathogens, the requirements in subparagraphs (C) and (D) of this paragraph and the requirements of one of the alternatives listed in paragraph (3) of this subsection must be met. Biosolids that meet the requirements of subparagraph (A) of this paragraph may be classified a Class A biosolids if a variance request is submitted in writing that is supported by substantial documentation demonstrating equivalent methods for reducing odors and written approval is granted by the executive director. The executive director may deny the variance request or revoke an approved variance if it is determined that the variance may potentially endanger human health or the environment or create nuisance odor conditions.

(C) The requirements of the chosen alternative for pathogen reduction from paragraphs (2) and (3) of this subsection must be met prior to or at the same time as the vector attraction reduction requirements, except the requirements in §312.83(b)(6) - (8) of this title (relating to Vector Attraction Reduction).

(D) Either the density of fecal coliform in the biosolids must 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 must be less than three Most Probable Number per four grams of total solids (dry weight basis) at the time the biosolids are used or disposed of, at the time the biosolids are prepared for sale or given away in a bag or other container for land application, or at the time the biosolids or material derived from biosolids are prepared to meet the requirements in §312.41(b), (c), (e), or (f) of this title (relating to Applicability).

(2) Compliance alternatives--Class AB.

(A) Alternative 2. The temperature and pH of the biosolids must be maintained at specific values for specific periods of time.

(i) The pH of the biosolids must be raised to above 12 and must remain above 12 for 72 hours.

(ii) The temperature of the biosolids must be above 52 degrees Celsius for 12 hours or longer during the period that the pH of the biosolids is above 12.

(iii) At the end of the 72-hour period during which the pH of the biosolids is above 12, the biosolids must be air dried to achieve a percent solids in the biosolids greater than 50%.

(B) Alternative 3. The biosolids must be analyzed prior to pathogen treatment to determine whether the biosolids contains enteric viruses and viable helminth ova.

(i) When the density of enteric viruses in the biosolids prior to pathogen treatment is less than one Plaque-forming Unit per four grams of total solids (dry weight basis), the biosolids are Class AB with respect to enteric viruses until the next monitoring episode for the biosolids.

(ii) When the density of enteric viruses in the biosolids prior to pathogen treatment is equal to or greater than one Plaque-forming Unit per four grams of total solids (dry weight basis), the biosolids are Class AB with respect to enteric viruses when the density of enteric viruses in the biosolids 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 biosolids that meet the enteric virus density requirement are documented.

(iii) After the enteric virus reduction in clause (ii) of this subparagraph is demonstrated for the pathogen treatment process, the biosolids continue to be Class AB 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 clause (ii) of this subparagraph.

(iv) When the density of viable helminth ova in the biosolids prior to pathogen treatment is less than one per four grams of total solids (dry weight basis), the biosolids are Class AB with respect to viable helminth ova until the next monitoring episode for the biosolids.

(v) When the density of viable helminth ova in the biosolids prior to pathogen treatment is equal to or greater than one per four grams of total solids (dry weight basis), the biosolids are Class AB with respect to viable helminth ova when the density of viable helminth ova in the biosolids 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 biosolids that meet the viable helminth ova density requirement are documented.

(vi) After the viable helminth ova reduction in clause (v) of this subparagraph is demonstrated for the pathogen treatment process, the biosolids continue to be Class AB 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 clause (v) of this subparagraph.

(C) Alternative 4. The biosolids must be analyzed prior to pathogen treatment to determine whether the biosolids contain enteric viruses and viable helminth ova.

(i) The density of enteric viruses in the biosolids must be less than one Plaque-forming Unit per four grams of total solids (dry weight basis) at the time the biosolids are used or disposed of, at the time the biosolids are prepared for sale or given away in a bag or other container for land application, or at the time the biosolids or material derived from biosolids are prepared to meet the requirements in §312.41(b), (c), (e), or (f) of this title.

(ii) The density of viable helminth ova in the biosolids must be less than one per four grams of total solids (dry weight basis) at the time the biosolids are used or disposed of, at the time the biosolids are prepared for sale or given away in a bag or other container for land application, or at the time the biosolids or material derived from biosolids are prepared to meet the requirements in §312.41(b), (c), (e), or (f) of this title.

(3) Compliance alternatives--Class A.

(A) Alternative 1. The temperature of the biosolids must be maintained at a specific value for a specific period of time.

(i) When the percent solids of the biosolids are 7.0% or higher, the temperature of the biosolids must be 50 degrees Celsius or higher; the time period must be 20 minutes or longer; and the temperature and time period must be determined using Equation D.1 of this clause, except when small particles of biosolids are heated by either warmed gases or an immiscible liquid.

Attached Graphic

(ii) When the percent solids of the biosolids are 7.0% or higher and small particles of biosolids are heated by either warmed gases or an immiscible liquid, the temperature of the biosolids must be 50 degrees Celsius or higher, the time period must be 15 seconds or longer, and the temperature and time period must be determined using Equation D.1 in clause (i) of this subparagraph.

(iii) When the percent solids of the biosolids is less than 7.0% and the time period is at least 15 seconds, but less than 30 minutes, the temperature and time period must be determined using the Equation D.1 in clause (i) of this subparagraph.

(iv) When the percent solids of the biosolids is less than 7.0%; the temperature of the biosolids is 50 degrees Celsius or higher; and the time period is 30 minutes or longer, the temperature and time period must be determined using Equation D.2 in this clause.

Attached Graphic

(B) Alternative 5 (Processes to Further Reduce Pathogens (PFRP)). Biosolids must be treated in one of the PFRP described in 40 Code of Federal Regulations (CFR) Part 503, Appendix B.

(C) Alternative 6 (PFRP Equivalent). Biosolids must be treated in a process that has been approved by the United States Environmental Protection Agency (EPA) as being equivalent to those in subparagraph (B) of this paragraph.

(b) Class B Biosolids.

(1) Compliance requirements--Class B.

(A) For biosolids to be classified as Class B with respect to pathogens, the requirements in subparagraphs (B) and (C) of this paragraph must be met. As an alternative for biosolids to be classified as Class B, the requirements of subparagraph (B) of this paragraph and paragraph (2) of this subsection must be met.

(B) The site restrictions in paragraph (3) of this subsection must be met when Class B biosolids, with respect to pathogens, are land applied.

(C) A minimum of seven representative samples of the biosolids must be collected within 48 hours of the time that the biosolids are used or disposed of during each monitoring episode for the biosolids. The geometric mean of the density of fecal coliform for the samples collected must be less than either 2,000,000 Most Probable Number per gram of total solids (dry weight basis) or 2,000,000 Colony-forming Units per gram of total solids (dry weight basis).

(2) Processes to Significantly Reduce Pathogens (PSRP) compliance alternatives--Class B. Biosolids must be treated in one of the PSRP described in 40 CFR Part 503, Appendix B, or must be treated by an equivalent process approved by the EPA, so long as all of the following requirements are met by the biosolids generator.

(A) Prior to use or disposal, all the biosolids must have been generated from a single location, except as provided in subparagraph (F) of this paragraph.

(B) An independent Texas licensed professional engineer must make a certification to the biosolids generator that the wastewater treatment facility generating the biosolids is designed to achieve one of the PSRP at the permitted design loading of the facility. The certification need only be repeated if the design loading of the facility is increased. The certification must include a statement indicating that the design meets all the applicable standards specified in 40 CFR Part 503, Appendix B.

(C) Prior to any off-site transportation or on-site use or disposal of any biosolids generated at a wastewater treatment facility, the licensed operator of the wastewater treatment facility or other responsible official who manages the PSRP at the wastewater treatment facility for the permittee, shall certify that the biosolids underwent at least the minimum operational requirements necessary in order to meet one of the PSRP. The acceptable processes and the minimum operational and recordkeeping requirements must be in accordance with established EPA final guidance.

(D) All certification records and operational records describing how the requirements of this paragraph were met must be kept by the generator for a minimum of three years and be available for inspection by executive director staff for review.

(E) In lieu of a generator obtaining a certification as specified in subparagraph (B) of this paragraph, the executive director will accept from the EPA a finding of equivalency to the defined PSRP.

(F) If the biosolids are generated from a mixture of sources, resulting from a person who prepares biosolids from more than one wastewater treatment facility, the resulting derived product must meet one of the PSRP, and meet the certification, operation, and recordkeeping requirements of this paragraph.

(3) Site restrictions.

(A) Food crops with harvested parts totally above the land surface that touch the biosolids/soil mixture must not be harvested from the land for at least 14 months after land application of biosolids.

(B) Food crops with harvested parts below the land surface must not be harvested for at least 20 months after land application of biosolids when the biosolids remain on the land surface for four months or longer prior to incorporation into the soil.

(C) Food crops with harvested parts below the land surface must not be harvested for at least 38 months after land application of biosolids when the biosolids remain on the land surface for less than four months prior to the incorporation into the soil.

(D) Food crops, feed crops, and fiber crops must not be harvested for at least 30 days after land application of biosolids.

(E) Domestic livestock must not be allowed to graze on the land for at least 30 days after land application of biosolids.

(F) Turf crops grown on land where biosolids are applied may not be harvested for at least one year after land application of biosolids when the harvested turf is placed on either land with a high potential for public exposure or a lawn.

(G) Public access to land with a high potential for public exposure must be restricted for at least one year after land application of biosolids.

(H) Public access to land with a low potential for public exposure must be restricted for at least 30 days after land application of the biosolids.

(c) Domestic septage.

(1) The site restrictions in subsection (b)(3) of this section must be met if domestic septage is land applied to agricultural land, forest, or a reclamation site.

(2) The pH of domestic septage land applied to agricultural land, forest, or a reclamation site must be raised to 12 or higher by alkali addition and, without the addition of more alkali, must remain at 12 or higher for a period of 30 minutes.

Source Note: The provisions of this §312.82 adopted to be effective October 13, 1995, 20 TexReg 7840; amended to be effective October 20, 2005, 30 TexReg 6743; amended to be effective October 2, 2014, 39 TexReg 7756; amended to be effective April 23, 2020, 45 TexReg 2542