(a)
Grease traps, interceptors, separators,
or holding tanks shall be provided for the proper handling of wastes
containing grease, oil, sand, and other harmful pollutants which may
interfere with the operation and maintenance of the POTW and shall
be constructed and maintained in accordance with the provisions outlined
in the city Code of Ordinances.
(b)
All restaurants, institutions, cafeterias,
or other establishments preparing or serving food to the general public
shall be required to install and maintain a grease trap for the efficient
removal of oil and grease from the waste stream. The design and installation
of such devices shall be subject to review and approval by the director.
(c)
All vehicle wash areas shall be equipped
with interceptors and oil separators for the removal of oils, grease,
and sand and other solids. The design and installation of such devices
shall be subject to review and approval by the director.
(d)
It shall be the responsibility of
the user to furnish, operate and maintain such pretreatment devices
as necessary to produce an effluent in compliance with this article
or other applicable ordinances.
(e)
Holding tanks shall be provided for
waste oils and other objectionable waste that is prohibited from being
discharged into the POTW, such as phosphates and vegetable debris.
Such holding tanks shall be constructed to prevent leakage and splashing
and shall be equipped with secondary containment to prevent spills
during operation and cleaning. Such tanks shall be maintained to preclude
odor and other nuisances and shall not be connected to the POTW or
in any other way allowed to be discharged to the POTW.
(Ordinance 05-0503-2 adopted 5/3/05)
(a)
Existing facilities required by this
article or other applicable ordinances to maintain a grease trap,
interceptor or separator not equipped with an adequately sized treatment
unit shall, within eighteen (18) months of the effective date of this
article (ordinance adopted May 3, 2005), install an adequately sized
grease trap, interceptor or separator in accordance with the specifications
of this article.
(b)
Existing facilities required by this
article or other applicable ordinances to maintain a grease trap,
interceptor or separator not equipped with the required pretreatment
device for the type of business shall, within nine (9) months of the
effective date of this article (ordinance adopted May 3, 2005), install
an adequately sized grease trap, interceptor or separator in accordance
with the specifications of this article.
(c)
In any circumstance where, in the
opinion of the director, the existing grease trap, separator, or interceptor
or the absence of a grease trap, separator, or interceptor poses a
serious threat or an ongoing problem to the sanitary sewer, is a public
nuisance, or poses a threat to public health or to the environment,
the director shall require the grease trap, interceptor, or separator
to be installed or replaced as and when necessary to remediate the
threat.
(d)
If a food establishment or any other
facility requiring a grease trap, interceptor, or separator shall
cease operation and shall be required to come into compliance with
other city codes, then such establishment or facility shall be required
to comply with this article before reopening.
(Ordinance 05-0503-2 adopted 5/3/05)
New businesses required by this article
or other ordinance to maintain a grease trap, interceptor or separator
shall install such unit prior to commencement of discharge to the
POTW.
(Ordinance 05-0503-2 adopted 5/3/05)
(a)
All nondomestic users shall request
a determination from the director whether a new or upgraded grease
trap, interceptor or separator will be required for his facility.
The director may approve alternate treatment technologies for some
types of wastes normally treated by a separator.
(b)
Where a user requests his facility
not be required to install a grease trap, interceptor or separator,
the director shall require data demonstrating the user is able to
comply with the limitations outlined in this article or other applicable
ordinances. The user may be subject to periodic monitoring to demonstrate
continued compliance. Requests not to install a grease trap, interceptor
or separator must be approved by the city manager.
(c)
Where a user requests the use of
alternate technology, the director shall require data demonstrating
the user is able to comply with the standards contained herein and
in other applicable ordinances. The user may be subject to periodic
monitoring to demonstrate continued compliance.
(d)
Such approvals shall be made on a
case-by-case basis.
(e)
The decision of the director can
be appealed to the city manager. The decision of the city manager
is final.
(Ordinance 05-0503-2 adopted 5/3/05)
(a)
Specifications outlined in this article
shall be considered minimum requirements only. It shall be the responsibility
of each user to have a grease trap, interceptor, or separator designed
and installed and maintained that will produce an effluent in compliance
with the requirements of this article or other applicable ordinances.
(1)
Grease traps, interceptors, and separators
shall meet or exceed the more stringent of specifications and requirements
set forth in this article and other applicable local, state, or federal
requirements.
(2)
An existing grease trap, interceptor,
or separator which is upgraded or replaced shall meet or exceed the
specifications set forth in this article and other applicable local,
state, or federal requirements.
(3)
Where a nondomestic user required
under this article to have a grease trap, interceptor, or separator
will occupy an existing building, the grease trap, interceptor, or
separator shall meet or exceed the requirements in this article and
other applicable local, state, or federal requirements.
(b)
Grease traps, interceptors, and separators
shall be constructed of impervious materials capable of withstanding
abrupt and extreme changes in temperature and capable of withstanding
the traffic load where installed.
(c)
Grease traps, interceptors, and separators
shall be installed outside the building wherever possible. Where it
is impossible to locate a grease trap outside the building, the trap
shall be located in a mechanical room or other separate area where
no food is stored or processed.
(d)
Grease traps, interceptors, and separators
shall be located so as to be readily and easily accessible for cleaning
and inspection of the pretreatment device and shall be equipped with
easily removable covers.
(1)
Manhole rings and covers, not less
than twenty-four (24) inches in diameter, shall be installed in the
lid of each compartment to facilitate easy access for cleaning and
inspection. The manholes shall be placed so that all internal piping
is accessible for maintenance and inspection. The cover shall be at
or near, but not below, the finished grade.
(2)
Where an existing interceptor or
separator is located inside a vehicle wash bay, the first chamber
shall be preceded by a grated catchbasin with openings not greater
than one-half (1/2) inch in diameter or shall be equipped with a grated
cover with openings not greater than one-half (1/2) inch in diameter
so that no solid material greater than one-half (1/2) inch in diameter
may enter the chamber. The cover on the secondary chamber shall be
watertight. Where the interceptor or separator is preceded by a grated
catchbasin, all covers on the separator shall be watertight.
(e)
Grease traps shall have a total liquid
capacity of not less than five hundred gallons unless he user has
demonstrated and received approval from the director for a smaller
capacity. Interceptors shall have a total liquid capacity of not less
than fifty (50) gallons. Separators shall have a total liquid capacity
of not less than five hundred (500) gallons. Grease traps and separators
shall be constructed with a minimum of two (2) compartments.
(1)
The primary compartment shall have
a detention time at peak flow of not less than fifteen (15) minutes.
(2)
The secondary compartment shall have
a detention time at peak flow of not less than five (5) minutes.
(f)
Plans for new grease traps, interceptors,
and separators or modifications to existing grease traps, interceptors,
and separators shall be submitted to the director and the city plumbing
inspector for review.
(1)
A description of plumbing fixtures
draining to the trap, the number of fixture units as determined by
the plumbing inspector and the calculations used to determine the
proposed capacity shall be included in the submittal.
(2)
The director and the plumbing inspector
shall be in agreement for approval of the final plans prior to the
issuance of any required plumbing or construction permits and subsequent
construction.
(g)
All grease traps, interceptors and
separators shall be equipped with an approved sampling port immediately
downstream of the treatment facility. Existing facilities without
an approved sampling port shall be equipped with an approved sampling
port within twenty-four (24) months of the effective date of this
article (ordinance adopted May 3, 2005).
(1)
Sampling ports shall be easily accessible
and safely located and shall be constructed in accordance with plans
approved by the director. Sampling ports shall be inspected by the
director prior to use.
(2)
Sampling ports shall be installed
by the owner at his expense and shall be maintained by him so as to
be safe and accessible at all times.
(3)
Sampling ports shall be constructed
to exclude the entry of stormwater and groundwater and the exit of
wastewater (prevention of infiltration/inflow, exfiltration/exflow).
(h)
Grease traps, interceptors, separators
and sampling ports shall be installed by a licensed plumber. Completed
grease traps, interceptors, and separators shall be subject to inspection
by the director and the plumbing inspector prior to connection to
the POTW.
(Ordinance 05-0503-2 adopted 5/3/05)
(a)
All liquid waste lines in food preparation
and dishwashing areas, except lines from restroom facilities, cooling
unit condensate, icemakers, and soft drink dispenser drain lines,
shall discharge through the grease trap.
(b)
The minimum size of grease traps
shall be determined according to the number of fixture units draining
through the trap, but shall, in no case, have a total liquid capacity
of less than five hundred (500) gallons unless the user has demonstrated
and received approval from the director for a smaller capacity. If
the director has not approved a small capacity then the capacity will
be determined by:
(1)
The total number of fixture units
multiplied by one hundred and fifty (150) gallons shall determine
the minimum total liquid capacity of the trap.
(2)
The primary chamber shall occupy
three-fourths (3/4) of the total liquid capacity of the trap.
(3)
The dividing wall between each chamber
shall completely divide the chambers (shall extend top to bottom)
except where the specific design of the separator provides for underflow,
in which case the wall shall not be greater than twelve (12) inches
from the bottom between the chambers rather than the flow traveling
through a pipe.
(4)
Fixture unit types and fixture unit counts are located on the city grease trap sizing criteria table (section
24.05.050).
(c)
Grease traps shall be equipped with
double cleanouts on the outside of the trap in both the influent (prior
to the trap) and effluent (after the trap) pipes.
(d)
The influent shall enter each chamber
below the static water level in accordance with the specifications
outlined in this section. The effluent shall discharge from below
the static water level of the chamber in accordance with the specifications
outlined in this section.
(1)
The influent line into all chambers
shall terminate no greater than eighteen (18) inches from the bottom
of the chamber.
(2)
The effluent from all chambers shall
discharge from the lower twelve (12) inches of the chamber.
(3)
There shall be no openings in any
influent or effluent pipe that will allow liquid to enter or exit
the chamber at any point other than the intake or discharge point
of the pipe.
(4)
The static water level shall be maintained
throughout the entire trap.
(Ordinance 05-0503-2 adopted 5/3/05)
(a)
Automatic car or truck washes and
coin-operated wash bays, drive-in or drive-through wash bays, hand
wash bays and other areas where vehicles are washed shall be equipped
with an interceptor and a two-stage separator. The interceptor and
the separator shall function as separate units.
(1)
An adequately sized interceptor shall
be provided for the removal of sand, grit and other objectionable
solids from the waste stream.
(2)
An adequately sized two-stage separator
shall be provided for the removal of oil and grease from the waste
stream.
(3)
Interceptors and separators shall
be minimally sized in accordance with the specifications outlined
in this article. Minimum sizing for any interceptor or separator may
be increased at the discretion of the director when necessary to protect
health, safety and property or to carry out the purposes and intents
of this article.
(b)
Interceptors shall have a minimum
detention time of not less than five (5) minutes. The minimum size
shall be in accordance with the specifications outlined in this article.
(1)
Interceptors may be located inside
the wash bay and may be equipped with a grated cover provided the
openings in the cover are not greater than one-half (1/2) inch in
diameter or per side of a rectangle. When located inside the wash
bay, the director may require a larger capacity interceptor be installed
to facilitate efficient sand and grit removal. Covers shall be easily
removable for cleaning and inspection.
(2)
Where located outside the wash bay,
the interceptor shall be equipped with solid watertight covers on
each chamber and shall be preceded by a catchbasin, located inside
the bay, equipped with a grated cover with openings not greater than
one-half (1/2) inch in diameter or per side of a rectangle. Covers
shall be easily removable for cleaning and inspection.
(3)
The inlet and outlet lines shall
be designed and installed to provide uniform flow and stilling in
the interceptor and to preclude sand from passing through the interceptor.
(A) Where a down pipe is
provided at the inlet, the pipe shall extend into the interceptor
a distance not less than one-third (1/3) from the static water level
to the bottom.
(B) The discharge pipe shall
extend into the interceptor a distance not less than one-third (1/3)
from the static water level to the bottom.
(c)
Separators shall be located outside
the wash bay and shall be equipped with solid watertight covers on
all chambers. Covers shall be easily removable for cleaning and inspection.
The influent shall enter each chamber below the static water level
in accordance with the specifications outlined in this section. The
effluent shall discharge from below the static water level of the
chamber in accordance with the specifications outlined in this section.
(1)
The influent line into all chambers
shall terminate no greater than eighteen (18) inches from the bottom
of the chamber.
(2)
The effluent from all chambers shall
discharge from the lower twelve (12) inches of the chamber.
(3)
There shall be no openings in any
influent or effluent pipe that will allow liquid to enter or exit
the chamber at any point other than the intake or discharge point
of the pipe.
(4)
The static water level shall be maintained
throughout the entire trap.
(d)
Minimum sizing for interceptors shall
be fifty (50) gallons per fixture unit (F.U.) draining into the interceptor,
but not less than the minimum sizes outlined below:
(1)
Manual hand wash bay or portable
washer: 50 gallons/F.U. but not less than 50 gallons/bay.
(2)
Coin-operated self-service wash bays:
50 gallons/F.U. but not less than 50 gallons/bay.
(3)
Automatic (drive-in and drive-through):
50 gallons/F.U. but not less than 50 gallons/bay.
(e)
(1)
Minimum sizing for separators shall
be one hundred and fifty (150) gallons per fixture unit draining into
the separator, but not less than the minimum sizes outlined below:
(A) Portable washer: Greater
of 500 gallons or 150 gallons/F.U.
(B) Single coin-operated
wash bay: Greater of 500 gallons or 150 gallons/F.U.
(C) Manual hand wash, single
bay only: Greater of 500 gallons or 150 gallons/F.U.
(D) 2 to 4 coin-operated
or manual hand wash bays: Greater of 1000 gallons + 200 gallons/bay
or 150 gallons/F.U.
(E) [More than] 4 coin-operated
or manual hand wash bays: Greater of 1000 gallons + 200 gallons/bay
or 150 gallons/F.U.
(F) Drive-through wash bay:
Greater of 500 gallons/bay or 150 gallons/F.U.
(2)
The primary chamber of the separator
shall occupy three-fourths (3/4) of the total liquid capacity of the
separator.
(3)
The dividing wall between each chamber
shall completely divide the chambers (shall extend top to bottom)
except where the specific design of the separator provides for underflow
not greater than twelve (12) inches between the chambers rather than
the flow traveling through a pipe.
(Ordinance 05-0503-2 adopted 5/3/05)
(a)
Holding tanks shall be constructed
and maintained to prevent discharge of waste cooking oils, motor oils
and other oils and fluids that are prohibited from being discharged
to the POTW.
(b)
Holding tanks shall not be connected
to the sanitary sewer or in any other way be allowed to discharge
to the POTW.
(c)
Holding tanks shall be provided with
secondary containment and such containment shall be capable of containing
not less than one hundred and ten (110) percent of the capacity of
the holding tank or the capacity of the largest tank plus water from
a maximum 24-hour/10-year rainfall event if exposed to rainwater,
whichever is greater.
(1)
Secondary containment shall be constructed
so as to control spills or splashes during operation and maintenance
and leaks.
(2)
Secondary containment shall not be
connected to any POTW or storm drain and shall not be allowed to drain
onto public or private property or to the waters of the United States.
(Ordinance 05-0503-2 adopted 5/3/05)
(a)
General requirements.
(1)
Grease traps, interceptors, separators
and holding tanks shall be operated in a safe and secure manner at
all times.
(2)
Areas surrounding grease traps, interceptors,
separators and holding tanks shall be maintained to facilitate immediate
access to the unit for cleaning and for inspection by the director
at all times.
(3)
Grease traps, interceptors and separators
shall be maintained in continuously efficient operation by the owner
or operator at his expense and shall produce an effluent in compliance
with this article and other applicable ordinances.
(4)
A user shall not remove any down
pipes or otherwise alter a grease trap, interceptor or separator in
any way which may allow oil, grease, sand, or other objectionable
materials to pass through the device into the POTW.
(5)
Where the city must clean associated
public sewers caused by inappropriate operation or maintenance, inadequate
design or installation, or inappropriate alteration of a grease trap,
interceptor or separator, costs of such cleaning shall be billed to
the user.
(A) In a case where several
users are discharging to the same sewer line, all the users shall
be equally liable except where the user provides written proof his
discharge could not have been a contributing factor.
(B) Proof shall consist
of demonstration of adequate sizing and installation; appropriate
cleaning (as documented by manifests and inspection documentation)
and valid analysis of a sample of the discharge collected within one
(1) week of the sewer cleaning activities. Analysis of samples collected
after sewer line cleaning will be accepted only where the grease trap,
interceptor or separator has been properly maintained and was not
cleaned within thirty (30) days of the sewer cleaning activities.
(6)
A user shall not increase the use
of water or in any other way attempt to dilute the waste stream in
lieu of adequate treatment.
(7)
The addition of hot water or the
use of emulsifiers, chemicals, or other agents or devices that may
cause oil, grease, or sand to pass through a treatment facility or
into the POTW sewer collection system is strictly prohibited.
(8)
Areas surrounding a grease trap,
interceptor, separator or holding tank shall be kept clean and free
of grease and odors and other materials at all times.
(A) Materials shall not
be splashed, spilled, allowed to overflow, or otherwise placed on
the area surrounding a grease trap, interceptor or separator.
(B) In the event materials
are spilled, splashed, overflowed, or otherwise placed on the surrounding
area, the generator or owner shall assure the materials are promptly
cleaned from the area and properly disposed.
(9)
Grease traps, interceptors, separators
and holding tanks shall be fully evacuated of all contents during
cleaning. If the capacity of the trap, interceptor, separator or holding
tank is greater than the capacity of the transport vehicle where full
evacuation is not possible in a single load, then the transporter
and the generator shall assure the contents are fully evacuated within
twenty-four (24) hours.
(A) No liquid waste shall
be returned to the trap, interceptor, separator or holding tank after
or during cleaning, either from the same or other trap, interceptor,
separator or holding tank.
(B) During cleaning, grease
residue shall be removed from piping and walls and the piping and
walls shall be inspected to assure the integrity of the device is
maintained.
(10)
Materials removed from traps, interceptors,
separators and holding tanks shall be utilized by industry, recycled,
or disposed at a facility designated by or acceptable to the generator
where the owner or operator agrees to receive the wastes and the disposal
facility has documentation showing the facility meets all requirements
of the state and federal authorities. All wastes shall be disposed
in a suitable manner in accordance with applicable federal, state,
and local laws.
(11)
Users required to maintain grease
traps, interceptors, separators, or holding tanks shall establish
a system of training designed to provide employees with appropriate
instruction on the proper use of such facilities.
(A) Such training system
shall provide employees at all levels of responsibility with a complete
understanding of the operation and maintenance of the pretreatment
device and the relation between appropriate waste disposal and efficient
operation of the pretreatment device. Such system should include:
(i) The importance and methods
of good housekeeping practices;
(ii) Acceptable waste disposal
practices, including proper disposal of different types of wastes;
(iii) Procedures for preventing
prohibited discharges; and
(iv) The proper response
to and notifications in case of spills or other accidental discharges.
(B) Periodic training sessions
shall be conducted to assure the employee understands the essential
elements of the system. New employees shall be trained immediately
upon employment.
(C) Users required to maintain
grease traps, interceptors, separators or holding tanks shall keep
documentation of training available for inspection.
(b)
Use of grease trap treatment
products.
(1)
Use of grease trap treatment products,
including bacteria, designed to digest the grease, is specifically
prohibited without prior written consent of the director.
(A) Acceptance of such products
for use may be considered only where a valid screening test, showing
the product’s ability to treat the waste and to produce an effluent
in compliance with this article, has been performed in accordance
with the methods outlined by the director.
(B) Screening tests for
grease trap treatment products shall be designed by the director.
(C) The results of screening
tests shall be subject to technical review by the director.
(D) All costs of screening
tests shall be borne by the user whether or not the product is accepted
for use.
(E) If a product is accepted
for use, each user shall obtain written permission from the director
to use the product.
(F) The director may revoke
permission to use such products where the effluent from the trap or
basin in which the product is used fails to meet the requirements
of this article.
(2)
Use of accepted grease trap treatment
products shall not relieve the user of minimum cleaning requirements
set forth in this article.
(3)
Use of accepted grease trap treatment
products may subject the user to monthly surcharge fees where such
usage causes the effluent concentrations to exceed the definition
of normal domestic wastewater. Surcharge fees may be levied for biochemical
oxygen demand, chemical oxygen demand, total suspended solids, or
ammonia.
(c)
Inspection and cleaning schedule.
(1)
Inspection, cleaning, and other necessary
maintenance of such facilities shall be conducted as often as needed
to assure the discharge is in compliance with the provisions of this
article or other applicable ordinances, but not less than once per
ninety (90) days.
(A) The trap, interceptor
or separator shall be cleaned as often as necessary, up to and including
daily, to assure compliance with this article or other applicable
ordinances.
(B) In no case shall the
accumulated grease, oil, or sand be allowed to occupy more than twenty-five
(25) percent of the capacity of the first stage.
(2)
The physical condition of the trap,
interceptor, or separator (piping, internal walls, side walls, etc.)
shall be inspected by the user each time the facility is cleaned.
Repairs, if needed, shall be made prior to further use.
(A) Repairs or modifications
shall be approved by the plumbing inspector and shall not be made
without the appropriate city permits.
(B) Inspection shall be
conducted by the plumbing inspector after repair and prior to refilling
or use. A copy of the inspection tag issued by the plumbing inspector
shall be maintained on-site by the user and a copy shall be sent to
the director.
(C) Documentation of repairs
shall be submitted to the director within thirty (30) days of the
date of repair, or earlier if specified in a notice of deficiency
or other director-issued document.
(3)
Grease traps, interceptors, and separators
shall produce an effluent in compliance with this article at the user’s
pumping schedule. Schedules inadequate to produce such effluent shall
be upgraded to as often as necessary, up to and including daily, or
the trap, separator, or interceptor shall be upgraded. Upgraded traps,
separators, or interceptors shall meet all requirements set forth
in this article or other applicable ordinances.
(4)
A user shall have any trap, interceptor,
or separator cleaned when ordered to do so by the director. Failure
to comply within forty-eight (48) hours after the request shall be
cause for the director to precipitate the cleaning and to bill the
user for such costs plus any added costs incurred by the city.
(d)
Cleaning schedule extensions.
(1)
The user may apply to the director
for an extension of the required cleaning frequency set forth in this
article. A user who wishes to apply for a cleaning schedule extension
shall notify the director, in writing, of the intent to apply for
an extension.
(2)
The director may grant an extension
on a required cleaning frequency on a case-by-case basis where the
user has demonstrated, with defensible analytical results, the specific
trap will produce an effluent in consistent compliance with this article
if such an extension is granted.
(3)
The notification of intent to apply
for an extension shall include:
(A) Facility information:
(i) The name and address
of the facility;
(ii) The name and telephone
number of the facility contact;
(iii) Normal business hours;
and
(B) Treatment unit information:
(i) The type of treatment
unit and the capacity in gallons;
(ii) A brief description
of the treatment unit;
(iii) The time(s) of day
the greatest hydraulic and organic loadings to the treatment unit
normally occur;
(iv) The date of the most
recent cleaning and inspection of the unit;
(v) A statement of the physical
condition of the unit; and
(vi) Where applicable, the
name of any treatment products used and a copy of the director’s
approval letter for the use of the product;
(C) A proposed sampling
schedule, including:
(i) The date(s) the user
proposes to collect the samples;
(ii) The times each sample
will be collected;
(iii) The name, telephone
number and qualifications of the person who will collect the samples;
and
(iv) The name and telephone
number of the laboratory which will analyze the samples;
(D) Other information as
may be requested by the director.
(4)
The user shall obtain approval of
the proposed sampling schedule prior to initiation of the sampling
and analyses. The user shall certify the sampling schedule will be
carried out as submitted or as approved. The director shall reserve
the right to modify a sampling schedule as deemed necessary.
(5)
The user shall be required to provide
analytical results for not less than four (4) oil and grease analyses
for samples collected during peak flow periods through the unit during
the normal working hours of a twenty-four-hour period.
(A) Samples shall be collected
at an approved sampling port and shall be collected by a qualified
person properly trained in the collection and handling of wastewater
samples.
(B) Samples shall be collected
seventy (70) to seventy-five (75) days after the most recent cleaning.
(C) Samples shall be analyzed,
separately, by a reputable laboratory using approved analytical procedures.
(D) The user shall submit
a written request for a cleaning schedule extension, including:
(i) A copy of the cleaning
and maintenance records for the treatment unit for the previous twelve
(12) months; and
(ii) A copy of the laboratory
analytical reports, including quality control data and appropriate
chains of custody.
Incomplete or unverifiable results
shall not be considered.
(6)
The director may grant extensions
to the cleaning schedule as follows:
(A) A thirty-day extension
may be granted where the average oil and grease concentration of the
analyses is less than seventy (70) percent of the concentration limit
and no single concentration exceeded eighty (80) percent of the concentration
limit.
(B) A sixty-day extension
may be granted where the average oil and grease concentration of the
analyses is less than fifty-five (55) percent of the concentration
limit and no single concentration exceeded sixty-five (65) percent
of the concentration limit.
(C) A ninety-day extension
may be granted where the average oil and grease concentration of the
analyses is less than forty (40) percent of the concentration limit
and no single concentration exceeded fifty (50) percent of the concentration
limit.
(D) In no case shall an
extension greater than ninety (90) days be granted.
(7)
Extensions granted shall begin on
the date the samples for which results were submitted were collected
as documented on the chain of custody.
(8)
Where an extension has been granted,
the unit shall consistently produce an effluent in compliance with
the terms of this article or other applicable ordinances. The director
shall reserve the right to collect and analyze samples of any user’s
discharge and may revoke, without notice, any extension where the
director believes it is in the best interest of the proper operation
of the POTW.
(A) Where an extension has
been granted and the results of any sample analysis exceed the oil
and grease limitation by twenty-five (25) percent or more, the user
shall immediately clean and inspect the trap and shall return to the
original cleaning schedule. Where the user has been required to return
to an original cleaning frequency, the user shall be required to submit
a new request for extension if desired.
(B) Where an extension has
been granted and the results of any sample analysis exceed the oil
and grease limitation by any magnitude but less than twenty-five (25)
percent, the user shall immediately clean and inspect the trap and
shall increase the established cleaning frequency by at least thirty
(30) days.
(C) Where an extension has
been granted and the city must clean associated public sewer lines
and the stoppage is traceable to or known or suspected to be caused
by the user’s facility, the user shall immediately clean and
inspect the trap and shall return to the original cleaning schedule.
The user will be required to submit a new request for extension if
desired.
(Ordinance 05-0503-2 adopted 5/3/05)
(a)
All fixtures with a potential to
carry grease-bearing waste shall be plumbed to the grease trap. The
first step in determining the appropriate size of the grease trap
is to calculate the total number of fixture units connected to the
trap. The following fixture unit counts shall be assigned to each
different kind of fixture:
Kind of Fixture
|
Trap and Trap Arm Size
|
Fixture Units
|
---|
3-compartment sink
|
1-1/2", 2"
|
3, 4
|
2-compartment sink
|
1-1/2"
|
2
|
Dishwasher
|
2"
|
4
|
Garbage grinder
|
2"
|
4
|
Wok stove
|
2"
|
4
|
Hand sink
|
–
|
0
|
Mop sink
|
–
|
0
|
Floor drains (2", 3", 4")
|
2", 3", 4"
|
2, 3, 4
|
Floor sinks (3", 4")
|
3", 4"
|
3, 4
|
Notes: Hand sinks and mop
sinks are not required to be plumbed to the grease trap. For indirect
waste systems where hub drains and floor sinks are used as receptors
for dishwashers, 2- and 3-compartment sinks, etc., the fixture unit
shall be twice (2x) the floor sink or hub drain fixture unit count.
In such cases the fixture count for the indirect waste source is not
counted.
(b)
The next step is to determine the
minimum flow rating of the grease trap. This is done by multiplying
the total fixture unit count times three gallons/minute:
Grease trap flow rating = Total fixture
unit count x 3 gallons/minute
(c)
The minimum liquid holding capacity
of the trap is calculated by multiplying the grease trap flow rating
(in gallons per minutes) times twelve minutes:
Grease trap liquid holding capacity
(gallons) = Grease trap flow rating x 12 minutes
(d)
Facilities using dishwashers, wok
stoves, or garbage grinders are required to install 2-compartment
traps with a 12-minute total retention time.
(e)
Upon approval from the director,
fixtures receiving non-grease-bearing wastes may be drained through
a grease trap, but shall not be included for grease trap sizing (i.e.,
condensate for coolers).
(Ordinance 05-0503-2 adopted 5/3/05)
(a)
The approved design for grease traps
shall be as follows:
(1)
The grease trap must be constructed
in accordance with the current plumbing codes adopted by the city,
as amended, and installed in a manner acceptable to the director (no
exceptions).
(2)
The grease trap shall have two compartments.
(3)
While operating at the trap’s
rated flow capacity, the first compartment must provide a retention
time of no less than seven minutes, and the second compartment must
provide a retention time of no less than five minutes, for a minimum
total of twelve minutes.
(4)
Trap inverts and vents shall be external
to the compartments.
(5)
The flow line to the trap (upstream
of inlet invert) must be at least 3 inches above the static water
level of the tank.
(6)
Similarly, the trap vent must be
at least 3 inches above the static water level of the tank.
(7)
The trap inlet must be at least 24
inches below the static water level of the tank, and the trap outlet
must be at least 12 inches above the floor of the tank.
(8)
Adequate flow diffusion features
must be provided to evenly distribute flow throughout the grease trap.
Examples of such features would include a flow diverter plate in the
primary compartment and “tee” piping on the tank outlet.
(9)
Each trap compartment shall be accessible
for cleaning and inspection purposes (no exceptions).
(b)
Exceptions to certain of these criteria
may be considered for approval in conjunction with the plan review
process. In such cases, engineering drawings and supporting performance
data must be submitted to and approved by the director of public works
prior to grease trap installation. Metal grease traps of alternative
designs may be approved for those sites needing grease traps of 250
gallons or less.
(c)
View a conceptual drawing of a typical
grease trap design.
(d)
View contact information for grease
trap manufacturers that are familiar with these criteria. However,
do not purchase any grease trap without first verifying with the city
office that the specific model will be approved for installation.
(Ordinance 05-0503-2 adopted 5/3/05)