Current through Register Vol. 30, No. 38, September 20, 2024
A. Interceptor
requirement. An applicant shall ensure that an interceptor as required by
R18-9-A309(A)(7)(c)
or necessary due to excessive amounts of grease, garbage, sand, or other wastes
in the sewage is installed between the sewage source and the on-site wastewater
treatment facility.
B. Interceptor
design. An applicant shall ensure that:
1. An
interceptor has not less than two compartments with fittings designed for
grease retention and capable of removing excessive amounts of grease, garbage,
sand, or other similar wastes. An interceptor may not accept human excreta or
toilet wastewater. Applicable structural and materials requirements prescribed
in R18-9-A314 apply;
2. Interceptors are located as close to the
source as possible and are accessible for servicing. The applicant shall ensure
that access openings for servicing are at grade level and gas-tight;
3. The interceptor size for grease and
garbage from non-residential kitchens is calculated using by the following
equation: Interceptor Size (in gallons) = M × F × T × S.
a. "M" is the number of meals per peak
hour;
b. "F" is the applicable
waste flow rate from Table 1, Unit Design Flows.
c. "T" is the estimated retention time:
i. Commercial kitchen waste, dishwasher or
disposal: 2.5 hours; or
ii. Single
service kitchen with utensil wash disposal: 1.5 hours;
d. "S" is the estimated storage factor:
i. Fully equipped commercial kitchen, 8-hour
operation: 1.0;
ii. Fully equipped
commercial kitchen, 16-hour operation: 2.0;
iii. Fully equipped commercial kitchen,
24-hour operation: 3.0; or
iv.
Single service kitchen, 1.5;
4. The interceptor size for silt and grease
from laundries and laundromats is calculated using the following equation:
Interceptor Size (in gallons) = M × C × F × T × S.
a. "M" is the number of machines;
b. "C" is the machine cycles per hour (assume
2);
c. "F" is the waste flow rate
from Table 1, Unit Design Flows;
d.
"T" is the estimated retention time (assume 2); and
e. "S" is the estimated storage factor
(assume 1.5 that allows for rock filter).
C. The applicant may calculate the size of an
interceptor using different factor values than those given in subsections
(B)(3) and (4) based on the values justified by the applicant in the Notice of
Intent to Discharge submitted to the Department for the on-site waste-water
treatment facility.
D. The
Department may require installation of a sampling box if the volume or
characteristics of the waste will impair the performance of the on-site
wastewater treatment facility.
