Section R18-9-E318. 4.18 General Permit: Constructed Wetland, Less Than 3000 Gallons Per Day Design Flow

A.      A 4.18 General Permit allows for the use of a constructed wet- land receiving wastewater treated to a level equal to or better than that specified in R18-9-E302(B).

1.        Definition. “Constructed wetland” means a treatment technology characterized by a lined excavation, filled with a medium for growing plants and planted with marsh vegetation. The treated wastewater flows horizontally through the medium in contact with the aquatic plants.

a.         As the wastewater flows through the wetland sys- tem, additional treatment is provided by filtering, settling, volatilization, and evapotranspiration.

b.        The wetland system allows microorganisms to break down organic material and plants to take up nutri- ents and other pollutants.

c.         The wastewater treated by a wetland system is dis- charged to a subsurface soil disposal system.

2.        An applicant may use a constructed wetland if further wastewater treatment is needed before disposal.

B.       Performance. An applicant shall ensure that a constructed wet- land is designed so that it produces treated wastewater that meets the following criteria:

1.        TSS of 20 milligrams per liter, 30-day arithmetic mean;

2.        BOD5 of 20 milligrams per liter, 30-day arithmetic mean;

3.        Total nitrogen (as nitrogen) of 45 milligrams per liter,

five-month arithmetic mean; and

4.        Total coliform level of 100,000 (Log10 5) colony forming units per 100 milliliters, 95th percentile.

C.      Notice of Intent to Discharge. The applicant shall comply with the Notice of Intent to Discharge requirements specified in R18-9-A301(B) and R18-9-A309(B).

D.      Design, installation, operation, and maintenance requirements. The permittee shall comply with the applicable design, instal- lation, operation, and maintenance  requirements in R18-9- A312, R18-9-A313(A), and R18-9-A313(B).

E.       Reference design.

1.        An applicant may use a constructed wetland that achieves the performance requirements in subsection (B) by fol- lowing a reference design on file with the Department.

2.        The applicant shall file a form provided by the Depart- ment for supplemental information about the proposed constructed wetland with the applicant’s submittal of the Notice of Intent to Discharge.

Historical Note

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).