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Oil/Water Separators
Highland Oil/Water Separators are designed for the removal of free-floating oil, grease, and settleable oily coated solids from oil/water mixtures associated with many types of petroleum, industrial, commercial, military, and municipal facilities. They can be installed below or above grade to help these facilities comply with tough spill and discharge regulations.
All Highland separators are equipped with our patented Corella® coalescers that combine the features of both a flat plate coalescer and a corrugated plate coalescer into a new “self-cleaning” design that performs better than traditional plate separators. Corella® accelerates the separation process and greatly reduces the level of oil and oily coated solids discharged into municipal sewer systems.
Highland oil/water separators are of the highest quality - constructed to American Petroleum Institute (API) and Underwriters Laboratories, Inc. (UL) specifications. They can serve as a stand-alone oil-water separator or can be readily adapted for use in conjunction with our polishing systems, like our trickle filter or polishing systems.
Highland Cylindrical Separators (Below Ground) |
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Highland Rectangular Separators
(Above Ground) |
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Oil/Water Separator Overview
Although oil/water separators are presently regulated as waste water treatment tanks, some authorities, include oil/water separators in their underground storage tank regulations. Accordingly, typical design is in conformance with an Underwriters Laboratories approved protected steel construction with robust corrosion control system such as a thorough coating of self-reinforcing, dielectric polyurethane. Additionally, the oil/water separator must be equipped with striker plates and coated internally with polyurethane to protect against internal corrosion. Double-walled oil/water separators provide additional protection with a rugged steel outer wall for secondary containment and electronic detection capability.
Oil/water separator design involves significant engineering. The system should be designed with consideration given to the personnel who must maintain and service the equipment.
• The separation chamber will require provision of three separate storage volumes for:
- oil spill capacity and separated oil storage at the top of the chamber
- sludge accumulation at the bottom of the chamber
- adequate flow-through detention time for separation of oil from the waste water stream.
• The activities producing a waste water stream at the vehicle maintenance facility will normally be discontinuous; minimum flow rates will frequently be at or near zero. Peak flow rates can be encountered for several hours and will normally be the flow rate of interest for design purposes.
• The oil/water separator must be readily accessible for maintenance and inspection.
• The use of below grade oil/water separators with large access man ways with removable covers are preferred at most locations. The cover should be designed so that it is easily removable by one person without the use of special equipment. • Inlet piping should be installed with few turns to limit turbulence.
• The oil/water separator should be provided with inlet and outlet valves as a means of shutting off flow for the purposes of cleaning and emergency situations.
• The absence of gravity flow to or from the oil/water separator will make it necessary to pump the waste waters. When gravity flow is not possible, pumping should be restricted to the effluent end of the oil/water separator. Pumping into an oil/water separator will increase the emulsified oil content. When pumping into an oil/water separator, a positive displacement pump (progressive cavity, diaphragm, etc.), at minimum gal. /min, and installed as far upstream as possible, will minimize emulsification.
• The drainage system should be kept from freezing at all times. Install the oil/water separator below the frost line or use a thermostatically controlled steam or electric heater.
• The oil/water separator must be properly vented in accordance with manufacturer's recommendations and applicable plumbing and safety codes for venting of combustible gases.
• All electrical components and wiring must be in accordance with applicable electrical and fire code standards for location and service intended.
Selection
and Design of Oil/Water Separators
• Enhance the separation
of oil from water through
added horizontal surface
area and by creating less
turbulent flow.
• Amplify the difference in
densities by providing
longer path for the fluid
to travel.
• Minimize the distance an
oil droplet needs to travel
to find another oil droplet
• Promote coalescence; as
the oil droplets collect
they coalesce with other
droplets and the larger
droplets rise more rapidly
to the water’s surface.
Oil/Water
Separator Operation and
Maintenance
• The oil/water separator should be filled with water
at all times for proper operation.
• Periodically inspect the floor and trench drains and sand and grit interceptors which are installed upstream of the oil/water separator. The amount of debris per-mitted to enter the oil/water separator must be minimized for maximum effectiveness.
• Periodically inspect the oil/water separator for sludge and oil level. oil/water
separators should be maintained as free of accumulated sludge and oil as possible.
• Regularly inspect the effluent in accordance with local codes and permits.
• Detergents and solvents should not be discharged into the oil/water
separator. Use of non-emulsifying, biodegradable cleaners is recommended.
• Waste water containing untreated sanitary sewage must be excluded from the oil/water separator.
• Waste oils should not be intentionally drained into the oil/water separator.
• Cleaning the oil/water separator internals with high pressure cleaning equipment from above is the procedure of choice. This prevents a confined space entry and the possibility of discharging hazardous material at grade during cleaning. Persons
servicing the oil/water separator must employ all mandated safety precautions.
