Arizona Administrative Code
Title 18 - ENVIRONMENTAL QUALITY
Chapter 9 - DEPARTMENT OF ENVIRONMENTAL QUALITY - WATER POLLUTION CONTROL
Article 10 - ARIZONA POLLUTANT DISCHARGE ELIMINATION SYSTEM - DISPOSAL, USE, AND TRANSPORTATION OF BIOSOLIDS
Section R18-9-1006 - Class A and Class B Pathogen Reduction Requirements
Universal Citation: AZ Admin Code R 18-9-1006
Current through Register Vol. 30, No. 52, December 27, 2024
A. An applicator shall ensure that all biosolids applied to land meet Class A or Class B pathogen reduction requirements at the time the biosolids are:
1. Placed on an active sewage sludge unit
unless the biosolids are covered with soil or other material at the end of each
operating day, or
2. Land
applied.
B. Biosolids that are sold or given away in a bag or other container for land application, or that are applied on a lawn or home garden, shall meet the Class A pathogen reduction requirements established in subsection (D).
C. Land on which biosolids with Class B pathogen reduction requirements are applied is subject to the use restrictions established in R18-9-1009.
D. Biosolids satisfy the Class A pathogen reduction requirements when the density of fecal coliform is less than 1000 Most Probable Number per gram of total solids (dry-weight basis), or the density of Salmonella sp. bacteria is less than three Most Probable Number per four grams of total solids (dry-weight basis), and any one of the following alternative pathogen treatment options is used:
1. Alternative 1. The pathogen treatment
process meets one of the following time and temperature requirements:
a. When the percent solids of the biosolids
are seven percent or greater, the temperature of the biosolids shall be held at
50° C or higher for at least 20 minutes. The temperature and time period is
determined using the equation in subsection (D)(1)(b), except when small
particles of the biosolids are heated by either warmed gases or an immiscible
liquid;
b. When the percent solids
of the biosolids are seven percent or greater, and small particles of the
biosolids are heated by either warmed gases or an immiscible liquid, a
temperature of 50° C or higher shall be held for 15 seconds or longer. The
temperature and time period is determined using the following equation:
D = time in days, and
t = temperature in degrees Celsius;
c. When the percent solids of the biosolids
are less than seven percent, the temperature of the biosolids is 50° C or
higher and the time period is 30 minutes or longer. The temperature and time
period shall be determined using the following equation:
D = time in days, and
t = temperature in degrees Celsius; or
d. When the percent solids of the biosolids
are less than seven percent, and the time of heating is at least 15 seconds,
but less than 30 minutes, the time and temperature is determined using the
following equation:
D = time in days, and
t = temperature in degrees Celsius.
2. Alternative 2. The pathogen
treatment process meets all the following parameters:
a. The pH of the quantity of biosolids
treated is raised to 12 or higher and held at least 72 hours;
b. During the period that the pH is above 12,
the temperature of the biosolids is held above 52° C for at least 12 hours;
and
c. At the end of the 72-hour
period during which the pH is above 12, the biosolids are air dried to achieve
a percent solids in the biosolids greater than 50%.
3. Alternative 3. The following conditions
are met:
a. The biosolids, before pathogen
treatment and until the next monitoring event, have an enteric virus density
less than one plaque-forming unit for four grams of total solids (dry-weight
basis);
b. The biosolids, before
pathogen treatment and until the next monitoring event, have a viable helminth
ova density less than one for four grams of total solids (dry-weight basis);
and
c. Once the density
requirements in subsections (D)(3)(a) and (D)(3)(b) are consistently met after
pathogen treatment and the values and ranges of the pathogen treatment process
used are documented, the biosolids continue to be Class A with respect to
enteric viruses and viable helminth ova when the values for the pathogen
treatment process operating parameters are consistent with the previously
documented values or ranges of values.
4. Alternative 4. The following requirements
are met at the time the biosolids are used or disposed or at the time the
biosolids are prepared for sale or given away in a bag or other container for
application to the land:
a. The biosolids have
an enteric virus density less than one plaque-forming unit for four grams of
total solids (dry-weight basis), and
b. The biosolids have a viable helminth ova
density less than one for four grams of total solids (dry-weight
basis).
5. Alternative
5. Composting.
a. Use either the within-vessel
or the static-aerated-pile composting method, maintaining the temperature of
the biosolids at 55° C or higher for three days; or
b. Use the windrow composting method,
maintaining the temperature of the biosolids at 55° C or higher for at
least 15 days. The windrow shall be turned at least five times when the compost
is maintained at 55° C or higher.
6. Alternative 6. Heat drying. The biosolids
are dried by direct or indirect contact with hot gases to reduce the moisture
content to 10% or lower by weight. During the process:
a. The temperature of the sewage sludge
particles shall exceed 80° C, or
b. The wet bulb temperature of the gas as the
biosolids leave the dryer shall exceed 80° C.
7. Alternative 7. Heat treatment. The
quantity of liquid biosolids treated are heated to a temperature of 180° C
or higher for at least 30 minutes.
8. Alternative 8. Thermophilic aerobic
digestion. Liquid biosolids are agitated with air or oxygen to maintain aerobic
conditions and the mean cell residence time of the biosolids is 10 days at 55
° to 60° C.
9. Alternative
9. Beta ray irradiation. Biosolids are irradiated with beta rays from an
accelerator at dosages of at least 1.0 megarad at room temperature
(approximately 20° C).
10.
Alternative 10. Gamma ray irradiation. Biosolids are irradiated with gamma rays
from certain isotopes, such as
60 Cobalt and
137 Cesium at dosages of at least 1.0
megarad at room temperature (approximately 20° C).
11. Alternative 11. Pasteurization. The
temperature of the biosolids is maintained at 70° C or higher for at least
30 minutes.
12. Alternative 12. The
Director shall approve another process if the process is equivalent to a
Process to Further Reduce Pathogens specified in subsections (D)(5) through
(D)(11), as determined by the EPA Pathogen Equivalency Committee.
E. Biosolids satisfy the Class B pathogen reduction requirements when the biosolids meet any one of the following options:
1. Alternative 1. The
geometric mean of the density of fecal coliform in seven representative samples
is 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. Alternative
2. Air drying. The biosolids are dried on sand beds or paved or unpaved basins
for at least three months. During at least two of the three months, the ambient
average daily temperature is above 0° C;
3. Alternative 3. Lime stabilization.
Sufficient lime is added to the biosolids to raise the pH of the biosolids to
12 after at least two hours of contact;
4. Alternative 4. Aerobic digestion. The
biosolids are agitated with air or oxygen to maintain aerobic conditions for a
specific mean cell residence time at a specific temperature between 40 days at
20° C and 60 days at 15° C;
5. Alternative 5. Anaerobic digestion. The
biosolids are treated in the absence of air for a specific mean cell residence
time at a specific temperature between 15 days at 35° C to 55° C and 60
days at 20° C;
6. Alternative
6. Composting. Using the within-vessel, static-aerated-pile or windrow
composting methods, the temperature of the biosolids is raised to 40° C or
higher for five consecutive days. For at least four hours during the five days,
the temperature in the compost pile exceeds 55° C; or
7. Alternative 7. The Director shall approve
another process if it is equivalent to a Process to Significantly Reduce
Pathogens specified in subsections (E)(2) through (E)(6), as determined by the
EPA Pathogen Equivalency Committee.
Disclaimer: These regulations may not be the most recent version. Arizona may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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