Ariz. Admin. Code § R18-9-E321 - 4.21 General Permit: Surface Disposal, Less Than 3000 Gallons Per Day Design Flow

A. A 4.21 General Permit allows for surface application of treated wastewater that is nominally free of coliform bacteria produced by the treatment works of an on-site wastewater treatment facility.

B. Performance. An applicant shall ensure that the treated waste-water distributed for surface application meets the following criteria:

1. TSS of 30 milligrams per liter, 30-day arithmetic mean;

2. BOD₅ of 30 milligrams per liter, 30-day arithmetic mean;

3. Total nitrogen (as nitrogen) of 53 milligrams per liter, five-month arithmetic mean;

4. Is nominally free of total coliform bacteria as indicated by a total coliform level of Log₁₀ 0 colony forming units per 100 milliliters, 95th percentile.

C. Restrictions. The applicant shall not install the disposal works if weather records indicate that:

1. Average minimum temperature in any month is 20°F or less, or

2. Over 1/3 of the average annual precipitation falls in a 30-day period.

D. Design requirements. An applicant shall ensure that:

1. The land surface application rate does not exceed the lowest application rate as determined under R18-9-A312(D) minus no greater than 50 percent of the evapotranspiration that may occur during the month with the least evapotranspiration in any soil zone within the top 5 feet of soil;

2. The design incorporates sprinklers, bubbler heads, or other dispersal components that optimize wastewater loading rates and prevent ponding on the land surface;

3. The design specifies containment berms:

a. Compacted to a minimum of 95 percent Proctor;

b. Designed to contain the runoff of the 10-year, 24-hour storm event in addition to the daily design flow; and c. Designed to remain intact in the event of a more severe rainfall event; and

4. The design incorporates placement of signage on hose bibs, human ingress points to the surface disposal area, and at intervals around the perimeter of the surface disposal area to provide notification of use of treated waste-water and a warning against ingestion.

E. Installation requirements. An applicant shall ensure that installation of the wastewater dispersal components conforms to manufacturer's specifications that do not conflict with this Article and to the design documents specified in the Construction Authorization issued under R18-9-A301(D)(1)(c).

F. Operation and maintenance. In addition to the requirements specified in R18-9-A313(B), the permittee shall operate and maintain the surface disposal works to:

1. Prevent treated wastewater from coming into contact with drinking fountains, water coolers, or eating areas;

2. Contain all treated wastewater within the bermed area; and

3. Ensure that hose bibs discharging treated wastewater are secured to prevent use by the public.

Notes

Ariz. Admin. Code § R18-9-E321

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