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Liquid petroleum hydrocarbon separators

Purpose

Liquid petroleum hydrocarbon separators (LPHS) serve for the separation of free petroleum and gasoline products that are washed off from parking and lay-out areas and the like. Coalescence is the basic physical process applied in the separator. This process can be completed with a sorption effect.

Process

Separation of petroleum products uses a principle of double-stage separation, i.e. first lighter petroleum products float over water surface and heavier particles settle down in a settling zone. Then pre-treated water flows through a coalescent filter and through a sorption filter, if need be, for final purification. Water flows through an inlet piping in a settling zone where a downflow baffle is installed. In this settling zone floating and settleable particles are separated with respect to their different gravity. Then pre-treated water flows over a partition to the other zone.

The other zone is provided with coalescent filters. When water flows through coalescent filter petroleum particles coagulate in clusters and float up to water surface from where they are skimmed off. If a sorption filter is fitted then floated and dispersed petroleum products are separated more efficiently. Sorption substances are put in polypropylene baskets that are attached to supporting frame of liquid petroleum hydrocarbon separator.

Legend: :

1. Inflow, 2. Downflow baffle (baffling), 3. Settling zone, 4. Overflow crest, 5. Scumboard (to trap floating impurities), 6. Baffle wall (baffling), 7. Coalescent filter I, 8. Coalescent filter, 9. Coalescent zone, 10. Effluent weir, 11. Outflow

Design Description

Liquid petroleum hydrocarbon separators are plastic tanks with inner equipment – coalescent and, if need be, sorption filter. Plastic liquid petroleum hydrocarbon separator is a complete packed container of expended polypropylene of a self-supporting design. It is positioned on a reinforced-concrete slab. Polypropylene tank is divided into two zones separated with a baffle wall. The top of the baffle wall is provided with an overflow. Several baffle walls and scumboards are installed inside the tank. The liquid petroleum hydrocarbon separator is designed with respect to valid hydrodynamic calculation and requirements for gravity separation of floating petroleum products including the effect of coalescent/sorption filtering. Entering wastewater is stilled down and then flows through a downflow baffle to a settling zone and through a coalescent filter, floating petroleum products are entrapped on water surface and are manually scummed off. If a separator is provided with a sorption filter then wastewater passes through this filter and the filter entraps even the smallest petroleum drops. Entrapped petroleum products are collected and have to be disposed of in special-purpose plants – incinerating plants, etc. If a sorption filter is installed it has to be replaced after its saturation with petroleum products. Special-purpose plants dispose of saturated sorption filters.
 
 

Structural drawing

Basic Specifications

Type Max Flow Area Dimensions in mm
l/s m2 LENGTH WIDTH HEIGHT INFLOW OUTFLOW DN
LPHS with coalescent filter NEL at outflow under 5 mg/l
LPHS 2 2 170 2000 1000 2020 1700 1500 100
LPHS 3 3 250 3000 1000 2020 1700 1600 150
LPHS 6 6 500 3000 1660 2080 1700 1600 150
LPHS 10 10 830 4000 1660 2080 1850 1650 200
LPHS 15 15 1250 4000 2160 2300 1950 1850 250
LPHS 20 20 1700 5000 2160 2300 1950 1850 250
LPHS 30 30 2500 6000 2160 2300 1950 1850 250
LPHS with coal. and sorption filters NEL at outflow – 0,5 mg/l
LPHS 2-S 2 170 3000 1000 2020 1700 1500 100
LPHS 3-S 3 250 4000 1000 2020 1700 1500 150
LPHS 6-S 6 500 4500 1660 2080 1700 1500 150
LPHS 10-S 10 830 6000 1660 2080 1850 1650 200
LPHS 15-S 15 1250 6000 2160 2300 1950 1750 250
LPHS 20-S 20 1700 7500 2160 2300 1950 1750 250
LPHS 30-S 30 2500 10300 2160 2300 1950 1750 2

Performance

Petroleum product content of wastewater passing through the separator is reduced by 85 up to 95 % with respect the separator type used. This high efficiency enables trouble-free outflow of effluent rainwater from parking areas directly to a recipient.

Layout in location

The figure shows the layout of a ADOS’s LPHS unit for treatment of rain waters from parking lots. A similar layout is applied for the LPHS location from garages, petrol stations, vehicle maintenance shops and the like. .