Current through Register Vol. 30, No. 38, September 20, 2024
A. A 4.12 General
Permit allows for the use of a textile filter receiving wastewater treated to a
level equal to or better than that specified in R18-9-E302(B).
1. Definition. For purposes of this Section,
a "textile filter" means a disposal technology characterized by:
a. The flow of wastewater into a packed bed
filter in a containment structure or structures. The packed bed filter uses a
textile filter medium with high porosity and surface area; and
b. The textile filter medium provides further
treatment by removing suspended material from the wastewater by physical
straining, and reducing nutrients by microbial action.
2. An applicant may use a textile filter in
conjunction with a two-compartment septic tank or a two-tank system if the
second compartment or tank is used as a recirculation and blending tank. The
applicant shall divert a portion of the wastewater flow from the textile filter
back into the second tank for further treatment.
3. An applicant may use a textile filter if:
a. Nitrogen reduction is desired,
b. The native soil is excessively
permeable,
c. There is little
native soil overlying fractured or excessively permeable rock, or
d. A reduction in setback distances or
minimum vertical separation is desired.
B. Performance. An applicant shall ensure
that a textile filter is designed so that it produces treated wastewater that
meets the following criteria:
1. TSS of 15
milligrams per liter, 30-day arithmetic mean;
2. BOD5 of 15
milligrams per liter, 30-day arithmetic mean;
3. Total nitrogen (as nitrogen) of 30
milligrams per liter, five-month arithmetic mean, or 15 milligrams, five-month
arithmetic mean per liter if documented under subsection (C)(4); and
4. Total coliform level of 100,000
(Log10 5) 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 filter manufacturer;
2. The filter model number;
3. A copy of the manufacturer's filter
warranty;
4. If the system is for
nitrogen reduction to 15 milligrams per liter, five-month arithmetic mean,
specifications on the nitrogen reduction performance of the filter system and
corroborating third-party test data;
5. The manufacturer's operation and
maintenance recommendations to achieve a 20-year operational life;
and
6. If a pump or aerator is
required for proper operation, the pump or aerator model number and a copy of
the manufacturer's warranty.
D. Design requirements. In addition to the
applicable requirements in
R18-9-A312,
an applicant shall ensure that:
1. The
textile medium has a porosity of greater than 80 percent;
2. The wastewater is delivered to the textile
filter by gravity flow or a pump;
3. If a pump is used to dose the textile
filter, the pump and appurtenances meet following criteria:
a. The textile media loading rate and
wastewater recirculation rate are based on calculations that conform with
performance data listed in the reviewed product list maintained by the
Department as required under
R18-9-A309(E),
b. The tank and recirculation components are
sized to contain the dose volume and a reserve volume above the high water
level alarm that will contain the volume of daily design flow, and
c. A control panel with a programmable timer
is used to dose the textile media at the applicable loading rate and wastewater
recirculation rate.
E. Installation requirements. In addition to
the applicable requirements in
R18-9-A313(A),
an applicant shall:
1. Before placing the
filter modules, slope the bottom of the excavation for the modules toward the
discharge point to minimize ponding;
2. Ensure that the bottom of all excavations
for the filter modules, pump, aerator, or other components is level and free of
debris, rocks, and sharp objects. If the excavation is uneven or rocky, the
applicant shall use a bed of sand or pea gravel to create an even, smooth
surface;
3. Provide the modules and
other components with anti-buoyancy devices to ensure they remain in place in
the event of high water table conditions; and
4. Provide a mechanism for draining the
filter module inlet line.
F. Operation and maintenance requirements. In
addition to the applicable requirements in
R18-9-A313,
the permittee shall not flush corrosives or other materials known to damage the
textile material into any drain that transmits wastewater to the on-site
wastewater treatment facility.
