Oil/Water Separator Policy
I. PURPOSE
This policy is designed to implement and enforce the oil and grease discharge
rules of the Sewer Use Ordinance Chapter 23 of the Charlotte City Code, Article
III, Section 23-80. Nothing in this policy shall negate or override requirements
contained in the Ordinance.
To ensure compliance with the City’s Sewer Use Ordinance (SUO), this policy
provides specific standards for oil /water separators’ location, type, size,
installation, construction, and maintenance. This policy regulates petroleum
hydrocarbon discharges to the Publicly Owned Treatment Works (POTW) and
may require the issuance of permits to certain non-domestic users and
enforcement of general requirements for all users (commercial and residential).
Charlotte-Mecklenburg Utilities- Environmental Management Division-System
Protection’s (CMU-EMD/SP) goal with this policy is to prevent excessive
introduction of petroleum hydrocarbons into the sewer system and wastewater
treatment plants. Petroleum hydrocarbons have the potential for creating sanitary
sewer overflows, hazardous conditions in the collection system, treatment plant
inhibitions, increased treatment cost, fines and other cost for the City.
II. OVERVIEW
All automotive repair operations, vehicle wash facilities and other washing
activities and all other Users shall provide means of preventing petroleum
hydrocarbons from entering the Sewer Collection System. Where an oil/water
separator currently exists or is required by Charlotte–Mecklenburg Utilities
(CMU), the Control Authority, it shall be maintained for continuous, satisfactory
and effective operation by the owner, leaseholder or operator at his expense.
Oil/water separator shall be of a type and capacity approved by CMU-EMD/SP
and Mecklenburg County Code Enforcement Department, LUESA, and shall be
located as to be readily accessible for cleaning and inspection. All Users are
encouraged to use proper oil and grease handling procedures.
It is unlawful for any facility to discharge petroleum hydrocarbons into the City's
collection system without authorization from the Control Authority. Authorization
shall be given to the users in the Control Authority’s Oil and Grease Control Program
in the form of a wastewater discharge permit. Upon initial inspection and approval, a
certificate shall be issued allowing the discharge of such wastes into the collection
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system. Each permit shall be issued for a time not longer than five years from the date
of the permit. The user shall apply for permit re-issuance a minimum of ninety (90)
days prior to the expiration of the user’s existing permit. The terms and conditions of
the permit may be subject to modification by the Control Authority during the term of
the permit as Codes and Policies are modified. The user shall be informed of any
proposed changes in the issued permit at least sixty days prior to the effective date of
the change(s). Any changes or new conditions in the permit shall include a reasonable
schedule for compliance.
As a condition precedent to the granting of an oil and grease permit, the recipient shall
agree to hold harmless the City and the City’s employees from any liabilities arising
from the user’s operations under this permit.
I. AUTHORITY
City of Charlotte Sewer Use Ordinance Synopsis (see actual Ordinance for full
language)
Sec. 23-79. Prohibited discharge standards.
(a) General prohibitions. No user shall discharge or cause to be discharged into the
POTW any pollutant or wastewater which causes interference or pass through.
The general prohibitions in this section apply to all users of the POTW.
(b) Specific prohibitions. No user shall discharge or cause to be discharged into the
POTW the following:
(16) Petroleum oil, non-biodegradable cutting oil, synthetic oil, or products of
mineral oil origin, in amounts that will cause interference or pass through.
(18) Any pollutant that will emulsify grease or oil or cause grease or oil to
solidify or become more viscous.
All other prohibited discharges as listed in the Sewer Use Ordinance, Article III, Section
23-79 shall apply.
Section 23-92. Authority to Inspect and Sample
(a) CMU personnel and other authorized employees of the city, bearing proper
identification, will inspect the facilities of any user to ascertain whether the
purpose of this article is being met and all requirements are being complied
with. Persons or occupants of premises where wastewater is created or
discharged shall allow CMU, the approval authority and the Environmental
Protection Agency or their representatives ready access at all times to all parts
of the premises to perform inspection, sampling, records examination and
copying or other duties. CMU, the approval authority and the Environmental
Protection Agency shall have the right to set up on the user's property such
devices as are necessary to conduct sampling, inspection, compliance
monitoring and/or metering operations. Where a user has security measures in
force which would require identification and clearance before entry into his
premises, the user shall make arrangements with his security guards so that,
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upon presentation of identification (identification being defined as the pieces
of identification supplied by CMU, the state or the Environmental Protection
Agency to their employees), personnel from CMU, the approval authority and
the Environmental Protection Agency will be permitted to enter and perform
their specific responsibilities without delay. Denial of CMU's, the approval
authority's or the Environmental Protection Agency's access to the user's
premises or portions thereof shall be a violation of this article. Denial of
access may also occur if a user fails to provide without unreasonable delay,
such facilities, equipment, or devices as are reasonably necessary to permit
personnel of CMU, the approval authority or the Environmental Protection
Agency from performing their duties in a safe manner. Unreasonable delays
may constitute denial of access. Any delay of more than five minutes may be
considered unreasonable.
(b) At all times, CMU shall retain the authority to inspect the POTW and to
sample and analyze wastewater in the POTW for any purpose. (Code 1985, §
23-57)
North Carolina State Plumbing Code
Chapter 10 - Sections 1003.4 of the North Carolina State Plumbing Code
Oil separators required. At repair garages, car washing facilities with engine or
undercarriage cleaning capability and at factories where oily and flammable liquid
wastes are produced, separators shall be installed where all oil-bearing, greasebearing or flammable wastes shall be discharged before emptying into the
building drainage system or other point of disposal.
II. Definitions.
The following words, terms and phrases, when used in this chapter, shall have the
meanings ascribed to them in this section, except where the context clearly
indicates a different meaning:
Control authority means CMU.
Grease includes oils, fats, cellulose, starch, proteins, wax, or grease, whether
emulsified or not. These are substances that may solidify or become viscous at
temperatures between 32 degrees Fahrenheit and 150 degrees Fahrenheit (zero
degrees and 65 degrees Celsius).
Grit interceptor means a chamber or other device in a wastewater line which
causes the velocity of the flow of wastewater to be reduced so that grit and
other heavier solids can settle to the bottom of the device for removal.
Industrial user (IU) means any person who is a source of indirect discharge.
Oil means any mineral, animal, vegetable or synthetic pollutant that has the
following, general characteristics: slippery, combustible, viscous, liquid or
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liquefiable at room temperature, and soluble in various organic solvents, such
as ether, but not in water.
Oil/water separator means a device designed to separate and retain oils and
other light density, volatile liquids from wastewater for proper disposal,
rendering or recycling. For purposes of this article, an oil/water separator must
have two access ports to allow proper inspection, sampling and cleaning.
pH means a measure of the acidity or alkalinity of a substance, expressed as
standard units and calculated as the logarithm of the reciprocal of the
concentration of the hydrogen ions in grams per liter of solution.
Pollutant means any waste as defined in G.S. 143-213.18, dredged spoil,
solid waste, incinerator residue, filter backwash, sewage, garbage, sewage
sludge, munitions, medical wastes, chemical wastes, biological materials,
radioactive materials, heat, wrecked or discharged equipment, rock, sand,
cellar dirt, industrial waste, municipal waste, agricultural waste, and certain
characteristics of wastewater (e.g., pH, temperature, TSS, turbidity, color,
BOD5, cBOD5, NH3, COD, toxicity, or odor).
Pretreatment and treatment mean the reduction of the amount of pollutants,
the elimination of pollutants, or the alteration of the nature of pollutant
properties in wastewater prior to or in lieu of discharging or otherwise
introducing such pollutants into a POTW. The reduction or alteration can be
obtained by physical, chemical or biological processes; by process changes;
or by other means, except by diluting the concentration of the pollutants. For
the purposes of this article, equalization of flow shall be considered
pretreatment.
Publicly owned treatment works (POTW) means a treatment works or a
combination thereof, as defined by section 212 of the act (33 USC 1292),
which is owned by the city. This definition includes any devices or systems
used in the collection, storage, treatment, recycling, and reclamation of
sewage or industrial wastes of a liquid nature; any conveyances which convey
wastewater to the POTW treatment plant; plant and sewer maintenance
personnel; and microorganisms associated with the treatment process itself.
Stormwater means any flow occurring during or following any form of
natural precipitation and resulting there from.
User means any person who contributes, causes or permits the contribution of
wastewater into the POTW or proposes such a contribution.
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Vehicle wash facility means a facility used to clean vehicles or equipment
using water and/or cleaning compounds, with the resulting wastewater
discharged directly or indirectly into the POTW.
Wastewater means the liquid and water-carried, industrial and/or domestic
wastes from dwellings, commercial buildings, industrial facilities, mobile
sources, treatment facilities and/or institutions together with any groundwater,
surface water, and/or stormwater that may be present, whether treated or
untreated, which are contributed to or permitted to enter the POTW.
III. GENERAL REQUIREMENTS
1. Every user with the potential to discharge one or more of the following
pollutants into the POTW, as determined by CMU, shall be required to
install an oil/water separator and grit interceptor approved by CMU: oil,
kerosene, gasoline, naphtha, wax, tri-sodium phosphate and any lightdensity and volatile liquid. Substances that will emulsify oil or grease shall
not be used in any oil/water separator required.
2. Every user required to install an oil/water separator shall install a grit
interceptor approved by CMU and Mecklenburg County Code
Enforcement. Every vehicle wash facility shall install an oil/water
separator and a grit interceptor approved by CMU and Mecklenburg
County Code Enforcement. A grit interceptor required by the SUO or
other applicable law shall be installed in a drainage line so that wastewater
flows into the grit interceptor before entering an oil/water separator
installed in accordance with this policy. Establishments where oil &
grease handling facilities are not in accordance with this standard, a
compliance schedule shall be given with a deadline not to exceed 6
months for compliance.
3. Wastewater, grease, grit and other materials removed in any manner from
facilities required by the SUO or other applicable law shall be disposed of
in accordance with applicable law and shall not be discharged directly or
indirectly into the POTW or otherwise placed back into such facilities
under any circumstances.
4. All facilities with oil/water separators, grit interceptors and other approved
facilities are required to maintain records concerning the dates and manner
of its inspection, maintenance and repair of such facilities; and of its
disposal of all wastewater, grease, oil, grit and other materials removed
from such facilities in accordance with applicable law. Such records shall
be kept on site for a minimum of three years and be made available upon
request.
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5. Oil/water separators, grit interceptors other approved facilities required by
the SUO or other applicable law shall be designed and installed so that all
portions are easily accessible for inspection, maintenance and sampling of
the effluent from such facilities.
6. Every user required by the SUO or other applicable law to install oil/water
separators shall adopt and implement procedures for the operation thereof.
Notice of such procedures shall be permanently posted on the user's
bulletin board or other prominent place.
7. Every user required to install oil/water separators by the SUO or other
applicable law shall adopt and implement a waste control plan based on
best management practices for the disposal of grease, oils, solids and
sludge removed from oil/water separators.
8. All facilities with oil/water separators shall be subject to periodic review,
evaluation and inspection by CMU representatives at any time. Results of
inspections will be given an overall rating, which may include
recommendations for correction and/or improvement where necessary.
9. A vehicle wash facility shall be designed, constructed, operated and
maintained to prevent any direct or indirect entry of stormwater into the
POTW.
10. All vehicle wash facilities must comply with grit interceptor and oil/water
separator requirements. If the vehicle washing is not performed inside a
building, then a canopy must cover the complete wash-bay area. The
perimeter of the wash-bay must have a berm, dike or curbing to exclude
storm water infiltration from surrounding areas into the sanitary sewer.
The wash-bay must be sloped to a center drain that flows to the sanitary
sewer.
11. Plans and drawings of proposed Oil/Water separator must be submitted to
Mecklenburg County Code Enforcement and CMU before installation to
approve equipment, manhole, etc.
12. All Establishments that are required to install oil/water separators shall
have written standard operating procedures for that equipment posted in a
location accessible to all operating personnel.
13. Oil/water separators shall be pumped out and cleaned, at a minimum when
75% of the retention capacity is filled with oils and/or solids, or on a more
frequent schedule as determined by the owner/operator or CMU.
14. Any establishment whose effluent discharge to the sewerage system is
determined by CMU to cause interference in the conveyance or operation
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of the sewerage system may be required to sample its’ effluent and have it
analyzed for pollutants, that will be determined by CMU, at the expense of
the owner, lease holder or operator. Results of such analyses shall be
reported to CMU.
15. All establishments that have oil and grease in their wastewater discharge
shall develop and implement a Waste Minimization Plan pertaining to
disposal of grease, oils, solids and sludge.
IV. SPECIAL VEHICLE AND MOBILE WASHING WASTEWATER
DISCHARGE REQUIREMENTS
Discharging of wash water, sometimes referred to as Cosmetic Cleaning water,
from some washing activities into the sanitary sewer system is acceptable if
certain conditions are met.
1. A maximum of 100 gallons per day may be discharged into a sewer
cleanout, sink, toilet or floor drain at your facility or the facility where
washing is conducted (with owner’s consent) with an oil sock and some
type of grit screening recommended. You may be able to discharge at an
offsite location, such as a car wash, but you should obtain consent from
the business owner first. Discharging into a sewer manhole is strictly
prohibited.
2. Discharges of over 100 gallons per day and less than 1000 gallons per day
require an oil/water separator and grit screening of some type before the
cleanout and other drains.
a. The pH must be between 6.0 and 12.0. Check pH with pH test
strips.
b. Filter the wash water if it contains debris, fiber, paint chips, or
other suspended solids
c. Use absorbent socks, pads or clay (“kitty litter”) to remove
petroleum-based products (if present).
d. The wash water must not contain hazardous substances that would
qualify it as a hazardous waste (corrosive, flammable, reactive or
toxic).
e. Wash water from the cleanup of a hazardous material spill cannot
be discharged into the sanitary sewer
f. Wash water discharged must be in compliance with SUO Specific
Pollutant Limitations.
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3. Discharges over 1000 gallons per day and wash water resulting from
activities such as engine/ equipment degreasing, acid washing of
unpainted vehicles or washing of tankers or boxcars will require pretreatment prior to discharging into the sanitary sewer system and will
necessitate review for a possible special use permit.
4. Contact Charlotte-Mecklenburg Utilities-Environmental
Management/System Protection at (704) 336-4407 for more information
on special use permits.
V. CONSTRUCTION STANDARDS
New Facilities
All facilities’ oil/water separators shall be designed and installed in accordance
with North Carolina State Plumbing Codes and CMU guidelines and policies.
Non-process sanitary wastewater lines shall not be connected to oil/water
separators. All oil/water separators shall have two access ports that will allow for
inspection, sampling, and cleaning.
1.
All new commercial and industrial facilities which use or have the potential to
discharge oil(s) shall be required to install an approved oil/water separator.
All separators shall be adequately sized to remove oil(s) to levels that comply
with the Sewer Use Ordinance limits (100 mg/l) and other discharge limits and
Mecklenburg County Code Enforcement requirements.
2.
No new facilities which use or have the potential to discharge oil(s) will be
allowed to initiate operations until approved oil/water separator equipment has
been installed.
3.
All oil/water separators, whether singular or multiple tanks in series, must
have each chamber directly accessible from the surface to provide means for
servicing and maintaining the equipment operation in proper condition.
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Sewer Use Ordinance Specific Pollutant Limitations
CBOD
250.0
mg/l
TSS
250.0
mg/l
NH 3
25.0
mg/l
Ammonia as N
20.0
mg/l
Arsenic
0.003
mg/l
Cadmium
0.003
mg/l
Chromium
0.05
mg/l (total chromium)
Copper
0.061
mg/l
Cyanide
0.015
mg/l
Lead
0.049
mg/l
Mercury
0.0003
mg/l
Nickel
0.021
mg/l
Silver
0.005
mg/l
Total Petroleum hydrocarbons
100.0
mg/l
Zinc
0.175
mg/l
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Existing Facilities
1.
All existing commercial and industrial facilities shall have Mecklenburg
County Code Enforcement approved oil/water separators and follow the
requirements for New Facilities. Facilities without oil and water separators
will be given a compliance deadline not to exceed six months from the date of
notification to have approved equipment installed and in compliance with this
standard. Failure to do so will be considered a violation of the City of
Charlotte Sewer Use Ordinance and may subject the facility to penalties and
escalated enforcement.
2.
In the event an existing facility’s oil and water separator is either underdesigned or substandard in accordance with this policy, the owner(s) will be
notified in writing of the deficiencies and required improvements, and given a
compliance deadline not to exceed (6) months to conform with the
requirements of this policy.
3.
CMU approval of flow control devices and oil / water separator design must be
obtained prior to installation.
4.
The use of emulsifiers is strictly prohibited from use in oil and water
separators.
VI. EXCEPTIONS
Under certain circumstances, the interceptor size and location may need special
exceptions to this policy. If an exception to this policy is requested, the User
must demonstrate that the size and location will not cause the facility’s discharge
to be non-compliant with the Sewer Use Ordinance and prevent potential harm to
the sanitary sewer system.
VII. ENFORCEMENT
Enforcement of this policy shall be in accordance with the provisions of the CMU
ENFORCEMENT RESPONSE PLAN. Failure to comply with this standard may
be grounds for penalty imposition and /or discontinuance of service.
Additionally, failure to comply may result in the notification to the Mecklenburg
County Code Enforcement.
This policy maybe modified or changed by CMU at any time in accordance with the
requirements of the City Code, North Carolina General Statute and Federal Regulations.
Should there be any questions concerning this policy, all questions should be directed to
the Charlotte-Mecklenburg Utilities- Environmental Services Facility-System Protection
at (704) 336-4407 or mailed to 4222 Westmont Drive, Charlotte, NC 28217.
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