Current through Register Vol. 30, No. 38, September 20, 2024
A. A 4.15 General
Permit allows for the construction and use of an aerobic system that uses
aeration for treatment
1. Definition. For
purposes of this Section, an "aerobic system" means a treatment unit consisting
of components that:
a. Mechanically introduce
oxygen to wastewater,
b. Typically
provide clarification of the wastewater after aeration, and
c. Convey the treated wastewater by pressure
or gravity distribution to the disposal works.
2. An applicant may use an aerobic system if:
a. Enhanced biological processing is needed
to treat wastewater with high organic content,
b. A soil or site condition is not adequate
for installation of a standard septic tank and disposal works under
R18-9-E302,
c. A highly treated
wastewater amenable to disinfection is needed, or
d. Nitrogen removal from the wastewater is
needed and removal performance of the system is documented according to
subsection (C)(6).
B. Performance.
1. An applicant shall ensure that the aerobic
system is designed so that the treated wastewater released to the native soil
meets the following criteria:
a. TSS of 30
milligrams per liter, 30-day arithmetic mean;
b. BOD5 of 30
milligrams per liter, 30-day arithmetic mean;
c. Total nitrogen (as nitrogen) of 53
milligrams per liter, five-month arithmetic mean, or as low as 15 milligrams,
five-month arithmetic mean per liter if documented under subsection (C)(6); and
d. Total coliform level of 300,000
(Log10 5.5) colony forming units per 100 milliliters,
95th percentile.
2. An
applicant may use an aerobic system that meets the following less stringent
performance criteria if the aerobic technology is listed by the Department
under
R18-9-A309(E)
and the Department bases its review and listing on the technology being less
costly and simpler to operate when compared to other aerobic technologies:
a. TSS of 60 milligrams per liter, 30-day
arithmetic mean;
b.
BOD5 of 60 milligrams per liter, 30-day arithmetic
mean;
c. Total nitrogen (as
nitrogen) of 53 milligrams per liter, five-month arithmetic mean, or as low as
15 milligrams, five month arithmetic mean per liter, if documented under
subsection (C)(6); and
d. Total
coliform level of 1,000,000 (Log10 7) colony forming
units per 100 milliliters, 95th percentile.
C. Notice of Intent to Discharge. In addition
to the Notice of Intent to Discharge requirements specified in
R18-9-A301(B)
and
R18-9-A309(B),
an applicant shall submit:
1. The name and
address of the aerobic system manufacturer;
2. The model number of the aerobic
system;
3. Evidence of performance
specified in subsection (B)(1) or (B)(2), as applicable;
4. A list of pretreatment components needed
to meet performance requirements;
5. A copy of the manufacturer's warranty and
operation and maintenance recommendations to achieve performance over a 20-year
operational life; and
6. If the
aerobic system will be used for nitrogen removal from the wastewater, either:
a. Evidence of a valid product listing under
R18-9-E309(E) indicating nitrogen removal performance, or
b. Specifications and third party test data
corroborating nitrogen reduction to the intended level.
D. Design requirements. In
addition to the applicable requirements in
R18-9-A312,
an applicant shall ensure that:
1. The
wastewater is delivered to the aerobic treatment unit by gravity flow either
directly or by a lift pump;
2. An
interceptor or other pretreatment device is incorporated if necessary to meet
the performance criteria specified in subsection (B)(1) or (2), or if
recommended by the manufacturer for pretreatment if a garbage disposal
appliance is used;
3. A clarifier
is provided after aeration for any treatment technology that achieves
performance that is equal to or better than the performance criteria specified
in subsection (B)(1); and
4. Ports
for inspection and monitoring are provided to verify
performance.
E.
Installation requirements. In addition to the applicable requirements in
R18-9-A313(A),
an applicant shall ensure that:
1. The
installation of the aerobic treatment components conforms to manufacturer's
specifications that do not conflict with Articles 1 and 3 of this Chapter and
to the design documents specified in the Construction Authorization issued
under
R18-9-A301(D)(1)(c);
and
2. Excavation and foundation
work, and backfill placement is performed to prevent differential settling and
adverse drainage conditions.
F. Operation and maintenance requirements.
The permittee shall:
1. Follow the applicable
requirements in
R18-9-A313(B),
and
2. Ensure that filters are
cleaned and replaced as necessary.
G. Reference design.
1. An applicant may use an aerobic system
that achieves the applicable performance requirements by following a reference
design on file with the Department.
2. An applicant using a reference design
shall submit, with the Notice of Intent to Discharge, supplemental information
specific to the proposed installation on a form approved by the
Department.