Introduction
The Shell Oil Products US, Martinez Refinery (Plant #A0011) occupies an approximately 850 acre site in Martinez, California. This refinery has an average daily throughput of 155,000 barrels (1 barrel = 42 gallons) of crude oil primarily from the San Joaquin Valley area. This crude oil is refined at the facility to produce 83,000 barrels of gasoline, 16,000 barrels of marine fuel oil, 27,000 barrels of jet fuel, 4,000 barrels of lube oils, 17,000 barrels of diesel, 7,000 barrels of asphalt and 7 tons of petroleum coke. In addition, Plant #A0011 also produces 150 to 175 tons of sulfur daily as a by- product of the on-site processes. These production rates generally reflect averages from the 200-2001 time period.

As part of the Bay Area Air Quality Management Districts' (the District) 2001 Clean Air Plan, the District, in cooperation with the California Air Resources Board (ARB) and the United States Environmental Protection Agency (U.S. EPA), is examining the wastewater systems for each of the Bay Area refineries to determine whether there are significant potential emission reductions from control of any remaining uncontrolled components of the wastewater systems, or through other measures. Most components of refinery wastewater systems are already controlled through compliance with District Regulation 8, Rule 8 (8-8), District New Source Review requirements, and EPA's National Emission Standard for Benzene Waste Operations (40 CFR Part 61, Subpart FF).

As part of this project a two day site visit (3/26/02 and 3/28/02) was conducted at Plant #A0011 to assess the availability of information related to the waste water system and to review the on-site collection and treatment of water which may have Volatile Organic Compounds (VOC) emissions impacts.

Site History
Plant #A0011 has been located in Martinez since early in the 20th Century. Initially established in 1915 by the Royal Dutch Petroleum Company, the Martinez site was ideal because of its natural deepwater port, potential for receiving crude oil via pipeline, and available markets. Initially the facility engaged in the production of kerosene, lubricating oils and asphalts. By the 1930's production of gasoline and various aviation fuels were included. The western side of the current refinery (west of Shell Avenue) is built on the initial site of the 1915 facility and is know as the "Heavy Oil Processing " area. This site is currently used primarily for the processing and storage of lube oils, fuel oils, asphalt, and other "heavy end" products.

In the 1960's the refining capacity of the facility was expanded to include a new crude unit, a hydrocracker, a catalytic cracker, an alkylation plant, a catalytic reformer, two sulfur recovery plants, numerous hydrotreaters and a hydrogen plant. This increased the facility's ability to convert San Joaquin crude into the gasoline needed for the expanding California automobile markets.

In 1982, the "Operations Central Area" was added to the refinery, again to optimize production capability. The most notable addition was the Flexicoker, which produces low BTU gas from coke for use as furnace fuel for the refinery. The project also increased hydrogen and sulfur production at the site. The final phase of the current construction was completed in the 1990's and added further hydrotreating capabilities, another hydrogen plant and a delayed coker to the facility.

On-site Waste Water Treatment
To understand the structure of the wastewater treatment at Plant #A0011, one needs to understand the phases of construction at the facility. Pre-1960's construction led to the building of Effluent Treatment Plant One biotreater (ETP-1). ETP-1 remains the main secondary treatment unit for wastewater created in the western side of the refinery. It is a 4 million-gallon biotreatment pond with floating aerators. The typical operating temperature is in the range of 32.2 oC (90oF) to 37.8 oC (100oF). Discharge from ETP-1 is hard piped to three dissolved air flotation clarifiers, then to a polishing pond, then to selenium treatment, next to a polishing pond, next to carbon filtration, and finally discharge via marine outfall adjacent to deepwater terminal. Overall the western side of the refinery wastewater system has open drains feeding to the API separator. The wastewater system immediately prior to the API and running to the dissolved nitrogen floatation tanks (DNF) is a closed vapor recovery system.

Primary factors influencing VOC emissions from the ETP-1 system is the temperature of the wastewater, and the potential emission sources that include an equalization tank (Tk-1067, floating roof, 3 million gallons) and the bioreactor ETP-1 itself. Tk-1067 is a floating roof tank which meets the control standards of the District tank rule: Regulation 8 Rule 5 and is considered Best Available Control Technology. Both Tk-1067 and the bioreactor may be VOC emission sources.

The post 1960's wastewater expansions were initially handled by the original effluent collection and treatment system that discharges to ETP-1. In the 1990s, selected streams were hard piped to a new treatment system that discharges to Effluent Treatment Plant Two (ETP-2), a 2 million-gallon tank with 4600-cfm jet aeration. Effluent discharging to ETP-2 is for the most part regulated by District Regulation 8, Rule 8 and the EPA's 40 CFR Part 61, Subpart FF. ETP-2 is the more modern of the two treatment schemes at the facility and boasts a totally enclosed system with vapor recovery from wastewater generation up to the ETP-2 aerator.

ETP-1 System
As previously stated the ETP-1 system is the main treatment conduit for wastewater created in the western side of the refinery. This area contains mostly "heavy end" production that includes lube oil production, cooling tower blow down, flexicoker stripped sour water, boiler blow downs, chemical waste water, sanitary sewage and crude storage area run off. In addition to these waste streams, process water from the co-generation plant, the lube oil hydrotreater, and sulfur plant #4 is commingled with the effluent to ETP-1.

The average daily flow in to ETP1 is estimated at 2,600 gallons per minute (gpm). This is usually gravity flowed via 30" and 18" lines to the head works of the main oil water separator for the treatment plant, the API. If the flow is excessive due to storms and rainwater run off, the facility has the ability to shunt water to uncovered Ponds 6 and 8 for temporary storage. Water stored in the ponds can then be mixed back into the effluent stream under normal conditions at a point before ETP-1's main aeration pond or to ETP-2.

At the API gross oil and solids are separated from the wastewater stream in a sealed system, consisting of two fore bays and two main bays. Primary control of VOC emissions from the API is by use of a water scrubbing system using ambient temperature domestic water with an approximate temperature of 15.6 oC (60oF). The scrubber system also uses one 55-gallon barrel of activated carbon as a secondary "back-up" VOC control. The carbon barrel is designed to control VOCs in the 500-ppm range.

Effluent from the API is then sent to two Dissolved Nitrogen Flotation (DNF) tanks to further remove any suspended oils/petroleum contained in the waste stream following initial treatment. The effluent temperature at this part of treatment is estimated to be between 37.8oC (100oF) and 48.9 oC (120oF). The DNF units are a closed system with VOC emissions minimized by a water scrubbing system with an activated carbon barrel system like that used at the API.

From the DNF's wastewater is sent directly to Tank 1067 for equalization and then to ETP-1's primary aeration pond. Tank 1067 is a 3 million-gallon floating roof tank that is used for surge storage.

From Tank 1067 the wastewater is sent to ETP1's main bio-aeration pond. This bio-aerator consists of a 4 million-gallon open pond approximately 9 feet deep at any point. This pond contains between 10 and 13 floating aerators moored by lines attached to perimeter anchors. Total horsepower of aerators is 675 horsepower. The numbers of aerators used varies depending on process and maintenance schedules. The temperature of the effluent at this point of treatment is usually between 26.7 oC (80oF) to 37.8 oC (100oF). From this point the effluent is separated into two streams. Bio-solids are removed and sent to the bio-solids thickener, and liquid effluent is sent through primary clarification to three dissolved air flotation clarifiers for secondary clarification.

From secondary clarification the effluent is commingled with effluent from ETP-2 and proceeds through two "polishing" ponds to the Selenium Treatment plant. This plant consists of a continuous ferrous flocculation system that precipitates approximately 20 tons per day of iron hydroxide sludge containing eight pounds of selenium. This sludge is dredged from the outfall pond of the flocculation plant and belt pressed for removal off-site. The outfall pond itself contains six 5 horse power aerators which continue to "polish" the effluent prior to treatment in the granular activated carbon (GAC) unit.

The final part of on-site wastewater treatment is the GAC unit. This unit consists of twenty-four vessels containing up to 480,000 pounds of GAC. This filtration removes any remaining turbidity, particulates or chemicals from the effluent stream. Maximum flow though GAC is 7,000 gpm, although flow rates at this level will quickly plug the GAC units with silt in one or two days. The final effluent then proceeds to the bay via a 24-inch multiport diffuser, located 20 feet under the Martinez Complex Wharf.

ETP-2 System
Most of the more modern construction (post 1990's) at Plant #A0011 is hard piped to ETP2. This consists of process drain out fall from the, stripped sour water, crude desalter and brine desalter effluent, cat reformer effluent, delayed coker effluent and recovered oil waste water. This effluent is initially pumped to two 1 million-gallon equalization tanks, located in the central operations zone of the refinery; both tanks have closed cone roofs and are linked to a vapor recovery system.

From these fixed roof tanks effluent is pumped in hard pipe to Tank 12519, a 6 million-gallon floating roof equalization/surge tank located in the wastewater treatment plant. Daily flows to this tank average 650 gpm.

From this point the effluent is piped to two fixed-roof DNF tanks where oils and solids are removed from the effluent and VOC emissions are controlled by a vapor recovery compressor system, refrigeration system or activated carbon canisters. This system represents the end of the hard piping for this effluent

From the DNF's effluent is piped to the main aeration basin for ETP-2. Here subsurface air jets force 4600 CFM of air through the two million-gallon biomass contained in the tank. At this point the effluent steam is at a temperature of between 32.2 oC (90oF) to 37.8 oC (100oF).

Having left the bio-aerator the effluent stream separates into two parallel gravity clarifiers. Here again the effluent is separated into two streams. Bio-solids are removed and sent to the bio-solids thickener, while liquid effluent is sent to pond 5E for "polishing."

Pond 5E is a one-million-gallon settling pond that flows to the selenium treatment plant on-site. Here the effluents from ETP-1 and ETP-2 are commingled and flow to the selenium plant via a number of other "polishing" ponds and are then routed to the bay via the GAC (see ETP1 above).

Bio-solids
When the waste streams separate at ETP-1 and ETP-2, bio-solids are sent via return lines to the biosolids thickener at a rate of approximately 20 gpm. From here there are two different paths to final wasting of this material. Thickened sludge is removed and stored temporarily on site, until it is centrifuged by an outside contractor and landfilled at a rate of 3,000 tons per year.

However, the preferred method of disposal is incineration at the facility's three CO boilers. This occurs continuously at a rate of up to 30 gpm.

It is also possible to return bio-solids to the biotreater from the thickener. This mechanism is also used to treat soaps produced at the facility. Rather than have huge slugs of soaps produced on-site being dumped directly to the waste water treatment system, they are collected in tankers, commingled with bio-solids at the thickener and returned to the clarifiers for biological treatment. This is done to avoid problems with foaming and up-sets of the biological treatment system.

Storm Water
In addition to these three treatment systems, Plant #A0011 also has five additional storm water collection systems which function in tandem with and separately from ETP-1 and ETP-2.

According to storm water flow maps provided by Shell, as well as their Regional Water Quality Control Board (RWQCB) permits, all storm water collected in the "western side" of the refinery is discharged via ETP-1 to the San Francisco bay. Storm water collected in the light oils processing area (LOP area) combines with runoff from tank farms in the same drainage basin and is contained by three ponds in series (commonly referred to as the Lake Slobodnik system), this system discharges directly into Peyton Slough which flows into the Carquinez Strait.

Storm water runoff from a 234-acre eastern tank farm area is collected in two ponds in series, which are each equipped with an oil baffle/weir and valve which is normally kept closed. The discharge point from the ponds is to an unnamed earthen drainage course at a point about 1500 feet south from the Mt. View Sanitary District treatment plant, then into Peyton Slough which flows into the Carquinez Strait.

Storm water runoff from a central 31-acre area containing an emergency flare is discharged from a pond equipped with an oil baffle/weir and valve (normally kept closed) into a drainage course at a point about 900 feet south of the Mt. View Sanitary District treatment plant, then into Payton Slough which flows into the Carquinez Strait.

Storm water runoff from a 7-acre propane/butane storage area is discharged from a pond which is equipped with an oil baffle/weir and a valve (normally kept closed) into a drainage course at a point about 600 feet south of the Mt. View Sanitary District treatment plant, then into Payton Slough which flows into the Carquinez Strait.

Finally, storm water runoff from an approximately 5-acre central maintenance and purchasing warehouse area is discharged to Contra Costa County storm drain culvert where it in turn discharges to an unnamed earthen drainage course and eventually to Payton Slough which flows into the Carquinez Strait.

Oil/Water Separators, Low Point Sumps and Drains
During the course of the site visit to Plant #A0011, two oil/water separators and one low point sump were identified as well as numerous drain and drain box configurations.

As part of the review of materials available for Plant #A0011 it was possible, from detail diagrams available for each phase of construction, to correlate the different drain designs with the drains observed on site. It has also been possible to "trace back" the 18" and 30" effluent lines from ETP-1 to the western side of the refinery. At present, information provided by drawings indicates three main drain collection stems in this area, one proceeding north down Shell Avenue, one proceeding west along Marina Vista and a third main conduit proceeding north by the main office building. All of these lines cross into the effluent treatment plant and are commingled at the head works for ETP-1.

The two oil water separators identified are also associated with the wastewater flow to ETP-1. Both the Corrugated Plate Interceptor (CPI) and the Gross Oil Separator (GOS) are located in the central area of the refinery and direct effluent flows into the main trunk lines for transport to ETP-1.

The CPI contrary to its name does not contain any corrugated plates. The plates were removed due to clogging by excess solids in the 500-gpm flow from the flexicoker plant. The CPI is a closed system and now functions as an oil water separator. VOC emissions are controlled by a water scrubber system backed up by an activated carbon barrel identical to those previously described. Effluent at this point is estimated to be at a temperature of 48.9 oC (120 oF). On the day of the site visit, two flat bed coke recovery vessels were positioned at the CPI to recover coke solids being pumped off the effluent at this point.

The GOS is of similar construction to the API at ETP-1 but does not utilize "flight scrapers" to push oil into the collection trough. Nor does it have solids collection sumps. It consists of a single bay and is primarily a gravity sump up stream of the API used to remove heavy oils and solids. Again this is a closed system with VOC emissions controlled by a water scrubber system backed up by an activated carbon barrel. This system accommodates a flow of approximately 650 gpm. Solids are recovered from this unit using a Vacuum truck and transported to the delayed coker for recycling.

One low point sump was identified in the eastern production areas. This sump is the main collection point for the stormwater run off for the light oils processing area. The contents of this sump are pumped to the Lake Slobodnik system that is discharged directly to Peyton Slough. This concrete sump did have some apparent residual hydrocarbon staining and maybe of interest as a VOC source in this study.

Drains and Junction Boxes
As part of this survey an extensive survey of the on site drain and junction boxes was under taken at this site. A range of construction was observed for the units at the facility, this survey was conducted on 6/12/02 and started in the Op's Central area of the refinery.

At the Hydrogen, Flexi-gas, Dimersol and Sulfur plants a range of different drain construction was observed. Pump stand drains varied between 6" to 4" and appeared to be open. Junction boxes in the units were more mixed with three prevailing types of construction 4' x 4' open boxes, 4' x 4' water sealed boxes and 4' x 4' "plug" sealed boxes. Similar drain and junction box construction was observed in the Flexicoker, cat cracker, cat gas plant and crude unit.

The only area that differed significantly from this construction was the Lubes area that represents the oldest construction at the facility. Here 1' x 1' and 3' x 2' open surface drains were observed around the pump stands.