( Adopted: 05/07/76; CARB Ex. Ord. G-73: 02/01/77; Readopted: 07/25/77; Amended: 08/24/94; Amended: 06/23/14)

MDAQMD Rule 464 464-1 Oil-Water Separators 

## RULE 464

Oil-Water Separators

(A) General (1) Purpose (a) The purpose of this rule is to reduce emissions of Volatile Organic Compounds (VOCs) from Oil-Water Separators. (2) Applicability (a) This rule applies to Oil-Water Separators inclu ding Air Flotation Units as defined in this rule, and process units or containe rs used to store skimmed oil or tar from Oil-Water Separators.



### (B) Definitions For the purposes of this rule only, the following d efinitions shall apply: (1) “Air Flotation Unit” – Equipment used to remove suspended matter, both oil and solid, from water by dissolving air under pressure and then releasing the air at atmospheric pressure in a tank or basin. (2) “Air Pollution Control Officer” (APCO)

– The person appointed to the position of Air Pollution Control Officer of the District pursuant to the provisions of California Health & Safety Code §40750 and his or her designee. (3) “California Air Resources Board” (CARB) – The C alifornia State Air Resources Board, the Executive Officer of CARB and his or her authorized representative, the powers and duties of which are described in Par t 2 of Division 26 of the California Health & Safety Code (commencing with Se ction 39500). (4) “Control Device” – Any device for reducing emis sions of VOC to the atmosphere. (5) “Effluent Water” – Any wastewater generated as a byproduct of industrial processes and containing dissolved, particulate org anic materials. Consists of a mixture of water with a petroleum product, includin g but not limited to the following: gasoline, kerosene, distillate fuel oils , residual fuel oils and lubricants. (6) “Fixed Cover” – Any cover made out of metal(s), polymer(s) or other material, and installed in a permanent position over the liquid.464-2 MDAQMD Rule 464 Oil-Water Separators (7) “Floating Cover” – Any cover made out of metal( s), polymer(s) or other material, which is in contact with a liquid surface at all ti mes. (8) “Forebay” – That section of a gravity-type sepa rator which (a) receives the untreated, contaminated Effluent Water from the pre separator flume, and (b) acts as a header which distributes the influent to the sepa rator channels. (9) “Fugitive Vapor Leak” (Leak) – The detection of 500 ppm or greater above background (expressed as methane), measured at the interface of the component using an appropriate hydrocarbon analyzer according to the procedures specified in EPA Method 21. (10) “Non-Contact Water Cooling Systems” – Any syst em which involves the cooling of organic vapors via coolant injected through pipi ng. There is no contact between the cooling fluid and the vapors being cooled. (11) “Oil-Water Separator” – Any device or piece of equipment, which utilizes the difference in density between oil or petroleum prod ucts and water to remove the oil or associated chemicals from the water, or any devi ce, such as a flocculation tank, clarifier, etc. that removes petroleum-derived comp ounds from wastewater. (12) “Operator” – Includes, but is not limited to, any person who owns, leases, supervises, or operates a facility and/or equipment

. (13) “Organic Materials” – Chemical compounds of ca rbon, excluding carbon monoxide, carbon dioxide, metallic carbides, metall ic carbonates and ammonium carbonate. (14) “Organic Vapors” – Chemical compounds of carbo n, excluding carbon monoxide, carbon dioxide, metallic carbides, metallic carbona tes and ammonium carbonate in their gaseous state. (15) “Overall Control Efficiency” – The product of the capture efficiency multiplied by the control efficiency; the weight per unit time of VOC removed by a control device divided by the weight per unit time of VOC e mitted by an emission source, expressed as a percentage. (16) “Petroleum Products” – Any crude oil or oil di stillate derived from tar sands, shale or coal, including, but not limited to gasoline, ke rosene, distillate fuel oils, residual fuel oils and lubricants. (17) “Reid Vapor Pressure” – The absolute vapor pre ssure of volatile crude oil and volatile nonviscous petroleum liquids, except liqui fied petroleum gases, as determined by ASTM D 323-89. (18) “United States Environmental Protection Agency ” (USEPA) – The United States Environmental Protection Agency, the Administrator of the USEPA and his or her authorized representative.MDAQMD Rule 464 464-3

Oil-Water Separators (19) “Vapor Recovery System” – A vapor-gathering sy stem capable of collecting VOC vapors and gases emitted during the operation of eq uipment. (20) “Volatile Organic Compound’ (VOC) – Any volati le compound containing at least one atom of carbon, excluding methane, carbon monox ide, carbon dioxide, carbonic acid, metallic carbides or carbonates, and ammonium carbonate, and those compounds listed in 40 CFR 51.100(s).



### (C) General Requirements (1) Fugitive Vapor Control Devices (a) A person shall not use any Oil-Water Separator subject to the provisions of Section (A)(2), unless it has been equipped with on e of the following vapor loss control devices, except when gauging or sampli ng is taking place: (i) A Fixed Cover with all openings sealed and tota lly enclosing the liquid contents of the compartment, except for such breathing vents as are structurally necessary; or (ii) A Floating Cover or double-deck type cover, eq uipped with closure seals that have no holes or tears, installed and ma intained so that gaps between the compartment wall and seal shall no t exceed one-eighth inch for an accumulative length of 97 pe rcent of the perimeter of the tank, and shall not exceed one-hal f inch for an accumulative length of the remaining three percent of the tank. No gap between the compartment wall and the seal shall exceed one-half inch; or (iii) Route all vapors to a Control Device with an Overall Control Efficiency (collection and control efficiencies) of at least 95 percent by weight of VOCs, measured according to the test m ethod specified in Section (G)(3). (b) Any oil-water separator subject to this rule sh all provide the following vapor loss control device: (i) A Fixed Cover for all Forebays, such that no li quid surface is exposed to the atmosphere. (c) Skimmed oil or tar removed from Oil-Water Separ ators shall be either charged to process units with feed or transferred t o a container with a control system with at least 90 percent control eff iciency by weight. A Control Device must be under District permit. (2) Requirements for Covers (a) Covers for oil-water separators shall meet the following requirements:464-4 MDAQMD Rule 464 Oil-Water Separators (i) The cover material shall be impermeable to VOCs , and free from holes or openings. (ii) Any gauging or sampling devices on the compart ment cover shall be covered. The latter cover shall be kept closed, wi th no visible gaps between the cover and the compartment, except when the sampling device is being used. (iii) Hatches on covers shall be kept closed and fr ee of gaps, except when opened for inspection, maintenance or repair. (iv) The perimeter of a cover, except for a Floatin g Cover, shall form a seal free of gaps with the foundation to which it i s installed. (3) Fugitive Vapor Leak Monitoring (a) When an instrument reading of 500 parts per mil lion (ppm) or greater is measured, a leak has been detected and the reading shall constitute a violation of this rule.



### (D) Exemptions (1) The provisions of this rule shall not apply to: (a) Segregated storm water runoff drain systems or to non-contact cooling water systems, where applicable. (b) Any system which collects and processes effluen t or process water contaminated with oil or other petroleum products a nd recovers less than 760 liters (201 gallons) a day of oil or other petr oleum products (c) Oils, tars and petroleum products with a Reid V apor Pressure of less than 25 mm Hg (0.5 pound per square inch).



### (E) Monitoring (1) Monitoring for Fugitive Vapor Leaks shall be pe rformed on a monthly basis and in accordance to test method specified in Section (G)( 1). Monitoring records shall be kept on file as prescribed in Section (F)(1). (2) Monitoring of the control device shall be perfo rmed on an annual basis and in accordance to the test method specified in Section (G)(4).



### (F) Record Keeping (1) A log of the monthly leak inspection shall be k ept on file at the facility. The log shall record, at a minimum, the following informati on: (a) Date of the inspection.MDAQMD Rule 464 464-5

Oil-Water Separators

(b) Documentation of all written or machine recorde d operator inspections, VOC measurements including corresponding background levels, source tests, repairs, replacements, and reinspection reco rds. (c) Leak determination method (shall be in accordan ce to the test method specified in Section (G)(1), using an appropriate h ydrocarbon analyzer). (d) Corrective action (date of leak repair and a wr itten justification for any repair interval in excess of 15 calendar days). (e) Inspector's name and signature. (2) Any person using an emission control device/sys tem pursuant to Section (C)(1) as a means of complying with provisions of this rule sha ll maintain records of key system operating and maintenance data for the purpo se of demonstrating continuous compliance during periods of emission pr oducing activities. The data shall be recorded in a manner as prescribed by the District. (3) Any facility claiming exemption pursuant to Sec tions (D)(1)(a) or (D)(1)(b) of this rule shall keep records to substantiate the claimed exempt status. (4) Any record required or produced pursuant to thi s rule shall be retained on site for a minimum of five (5) years and shall be made availab le to the APCO upon request.



### (G) Test Methods for Compliance Verification A violation determined by any one of these test met hods shall constitute a violation of the rule: (1) Fugitive Vapor Leaks - Detection of VOCs - EPA Method 21 shall be used to determine compliance with this rule in regards to f ugitive or VOC leaks. Instrument shall be calibrated with Method 21 using zero air (less than 10 parts per million (ppm) of hydrocarbon in air) with a mixture of methane or n-hexane. (2) Determination of Reid Vapor Pressure - Shall be determined by measuring the Reid Vapor pressure in accordance with Test Method for Vapor Pressure for Petroleum Products (Reid Method) , ASTM D 323-82 (April 8, 1987). (3) Control Device Efficiency - Determining the des truction or removal efficiency of a control device shall be: (a) For systems utilizing add-on control equipment, EPA Method 25 or 25A, as applicable and analysis of halogenated exempt compo unds shall be by ARB Method 22. (b) For incinerators or catalytic incinerators, EPA Method 25, unless the concentration of VOC in the outlet stream is below 50 ppm as carbon, in464-6 MDAQMD Rule 464 Oil-Water Separators which case EPA Method 25A shall be used. (c) Where add-on control equipment is utilized, col lection efficiency shall be determined by EPA document “Model Regulatory Langua ge for Capture Efficiency Testing,” August 3, 1990. (4) Any applicable alternative test method may be u sed so long as such method has been approved by USEPA, CARB and the APCO.

[SIP: See SIP Table at http://www.mdaqmd.ca.gov/Modules/ShowDocument.aspx? documentid=45 ]