Polyethylene oil separator

Overview
Hydrocarbon separators intended for car parks, garages, wash bays and service stations. Range includes several types and variants (Rosep, Rooil, RoPetrol) suited to treatment requirements for waters contaminated with oils and hydrocarbons.

Products / variants presented

• Rosep Class I
• Rosep bypass 10%
• Rosep bypass 20%
• Rooil Class I
• Rooil bypass 10%
• Rooil bypass 20%
• RoPetrol (traps for service stations)

Class I (description)
The Class I separator is designed to achieve an oil concentration below 5 mg/l under standard test conditions and when required to remove very fine oil droplets. A coalescing filter is installed upstream of the outlet to enhance separation: fine oil droplets coalesce into larger drops that then leave the coalescing element. Separators are fitted with a hydraulic inlet to slow and distribute the flow. Heavy solids settle to the bottom and light materials rise to the surface to be separated.

Bypass systems
Separators with bypass treat the full flow generated by rainfall intensities up to 6.5 mm/h (covering 99% of the flow). They are used on parking areas when full treatment of peak flows is not required or when limiting the risk of overflow during intense simultaneous rainfall is accepted.

Components and elements

• Sand / sludge separator (settling compartment)
• Coalescing filter
• Telescopic riser with cover
• Sampling shaft
• Hydraulic inlet (flow diffuser)
• Outlet designed to retain oil (option to fit an automatic shut-off valve)
• PE tank with barrier (for some models)
• Internal baffle and oil retention devices (automatic barriers)

Operation
The separation principle is as follows:

• Waste water flows into the separator inlet pipe.
• The inlet pipe disperses and moderates the water; heavy solids settle in the first compartment.
• Oil-contaminated water passes through the coalescing filter where flow slows and small oil droplets agglomerate into larger drops that rise to the surface.
• Treated water flows out via an outlet designed to retain oil; an automatic shut-off valve can be fitted to prevent overflow in case of excess oil.
• Limited accumulation of sludge and oil: sludge and oil are pumped out via maintenance openings provided for cleaning.

Sizing / formula
Formula provided for nominal size (NS):
NS = (Qr + fx * Qs) * fd

Legend of the formula

• NS = nominal volume in l/s
• Qr = maximum rainwater flow in l/s
• Qs = maximum wastewater flow in l/s
• fx = retention factor (depending on nature of release)
• fd = density factor for the appropriate light fluid

Typical applications
Car parks, garages, wash bays, service stations and other areas where surface water may be contaminated by oils, hydrocarbons and light liquids.

Features / technical specifications

• Design compliant with Class I requirements (target: oil < 5 mg/l under standard test conditions)
• Coalescing filter for droplet coalescence
• Bypass options for peak flow management (up to 6.5 mm/h)
• Settling compartment for heavy solids
• Sampling elements and telescopic riser options
• Outlet designed to limit oil passage; option for automatic shut-off valve
• Maintenance by pumping sludge and oil accumulations via designated openings
• Various sizes and configurations (Rosep, Rooil, RoPetrol) depending on application and flow