Ariz. Admin. Code § R18-9-B204 - Treatment Performance Requirements for a New Facility

A. Definition. "Week" means a seven-day period starting on Sunday and ending on the following Saturday.

B. An owner or operator of a new sewage treatment facility shall ensure that the facility meets the following performance requirements upon release of the treated wastewater at the outfall:

1. Secondary treatment levels.

a. Five-day biochemical oxygen demand (BOD₅) less than 30 mg/l (30-day average) and 45 mg/l (seven-day average), or carbonaceous biochemical oxygen demand (CBOD₅) less than 25 mg/l (30-day average) or 40 mg/l (seven-day average);

b. Total suspended solids (TSS) less than 30 mg/l (30-day average) and 45 mg/l (seven-day average);

c. pH maintained between 6.0 and 9.0 standard units; and

d. A removal efficiency of 85 percent for BOD_5, CBOD_5, and TSS;

2. Secondary treatment by waste stabilization ponds is not considered BADCT unless an applicant demonstrates to the Department that site-specific hydrologic and geologic characteristics and other environmental factors are sufficient to justify secondary treatment by waste stabilization ponds;

3. Total nitrogen in the treated wastewater is less than 10 mg/l (five-month rolling geometric mean). If an applicant demonstrates, using appropriate monitoring that soil aquifer treatment will produce a total nitrogen concentration less than 10 mg/l in wastewater that percolates to groundwater, the Department may approve soil aquifer treatment for removal of total nitrogen as an alternative to meeting the performance requirement of 10 mg/l at the outfall;

4. Pathogen removal.

a. For a sewage treatment facility with a design flow of less than 250,000 gallons per day at a site where the depth to the seasonally high groundwater table is greater than 20 feet and there is no karstic or fractured bedrock at the surface:

i. The concentration of fecal coliform organisms in four of the wastewater samples collected during the week is less than 200 cfu/100 ml or the concentration of E. coli bacteria in four of the wastewater samples collected during the week is less than 126 cfu/100 ml, based on a sampling frequency of seven daily samples per week;

ii. The single sample maximum concentration of fecal coliform organisms in a wastewater sample is not greater than 800 cfu/100 ml or the single sample maximum concentration of E. coli bacteria in a wastewater sample is not greater than 504 cfu/100 ml; and

iii. An owner or operator of a facility may request a reduction in the monitoring frequency required in subsection (B)(4)(a)(i) if equipment is installed to continuously monitor an alternative indicator parameter and the owner or operator demonstrates that the continuous monitoring will ensure reliable production of wastewater that meets the numeric concentration levels in subsections (B)(4)(a)(i) and (ii) at the discharge point;

b. For any other sewage treatment facility:

i. No fecal coliform organisms or no E. coli bacteria are detected in four of the wastewater samples collected during the week, based on a sampling frequency of seven daily samples per week;

ii. The single sample maximum concentration of fecal coliform organisms in a wastewater sample is not greater than 23 cfu/100 ml or the single sample maximum concentration of E. coli is not greater than 15 cfu/100 ml;

iii. An owner or operator may request a reduction in the monitoring frequency required in subsection (B)(4)(b)(i) if equipment is installed to continuously monitor an alternative indicator parameter and the owner or operator demonstrates that the continuous monitoring will ensure reliable production of wastewater that meets the numeric concentration levels in subsections (B)(4)(b)(i) or (ii) at the discharge point;

c. An owner or operator may use unit treatment processes, such as chlorination-dechlorination, ultraviolet, and ozone to achieve the pathogen removal performance requirements specified in subsections (B)(4)(a) and (b);

d. The Department may approve soil aquifer treatment for the removal of fecal coliform or E. coli bacteria as an alternative to meeting the performance requirement in subsection (B)(4)(a) or (b), if the soil aquifer treatment process will produce a fecal coliform or E. coli bacteria concentration less than that required under subsection (B)(4)(a) or (b), in wastewater that percolates to groundwater;

5. Unless governed by A.R.S. § 49-243(I), the performance requirement for each constituent regulated under R18-11-406(B) through (E) is the numeric Aquifer Water Quality Standard;

6. The performance requirement for a constituent regulated under A.R.S. § 49-243(I) is removal to the greatest extent practical regardless of cost.

a. An operator shall minimize trihalomethane compounds generated as disinfection byproducts using chlorination, dechlorination, ultraviolet, or ozone as the disinfection system or using a technology demonstrated to have equivalent or better performance for removing or preventing trihalomethane compounds.

b. For other pollutants regulated by A.R.S. § 49-243(I), an operator shall use one of the following methods to achieve industrial pretreatment:

i. Regulate industrial sources of influent to the sewage treatment facility by setting limits on pollutant concentrations, monitoring for pollutants, and enforcing the limits to reduce, eliminate, or alter the nature of a pollutant before release into a sewage collection system;

ii. Meet the pretreatment requirements of A.R.S. § 49-255.02; or

iii. For sewage treatment facilities without significant industrial input, conduct periodic monitoring to detect industrial discharge; and

7. A maximum seepage rate less than 550 gallons per day per acre for all containment structures within the treatment works. A sewage treatment facility that consists solely of containment structures with no other form of discharge complies with Article 2 Part B by operating below the maximum 550 gallon per day per acre seepage rate.

C. The Director shall incorporate treated wastewater discharge limitations and associated monitoring specified in this Section into the individual permit to ensure compliance with the BADCT requirements.

D. An applicant shall formally request in writing and justify an alternative that allows less stringent performance than that established in this Section, based on the criteria specified in A.R.S. § 49-243(B)(1).

E. If the request specified in subsection (D) involves treatment or disposal works that are a demonstration, experimental, or pilot project, the Director may issue an individual permit that places greater reliance on monitoring to ensure operational capability.

Notes

Ariz. Admin. Code § R18-9-B204

New Section adopted by final rulemaking at 7 A.A.R. 235, effective January 1, 2001 (Supp. 00-4). Amended by final rulemaking at 11 A.A.R. 4544, effective November 12, 2005 (05-3).