Dissolved Air Flotation for removal oils and fats

Aguambiente has recently finished supplying and installing a new physicochemical treatment system using dissolved air flotation to treat up to 240m3 per day at the wastewater treatment plant (WTP) at an oil recycling and biodiesel production company.

The physicochemical process using dissolved air flotation was positioned between the homogenisation-neutralisation and biological treatment processes.

Due to the nature of the company’s work, the effluent that reaches the homogenisation tank contains high levels of oil, which are difficult to remove. The proposed solution to the problem was to install a dissolved air flotation system in order to separate the oil and grease from the water.
The objective? To improve the quality of the water at the biological treatment outlet.

The dissolved air flotation unit is equipped with a flocculation tube, where the reaction between coagulants and flocculants takes place to enable the purification process.

When the dissolved air flotation process is preceded by coagulation-flocculation treatment, the performance in terms of separation of suspended solid matter is greatly improved, with up to 95% being easily removed; this entails a reduction in the DBO5 of at least 40%. This is due to the fact that the coagulation-flocculation process has been designed with a structure and size of floc that promotes the adhesion of dissolved air particles, with the result that separation by flotation is far greater and faster.
With a dissolved air flotation unit, the finest solid particles are eliminated along with any floating phases that may be present in the water (oil, grease, etc.).
Here you can see other references in water treatment with high oil content.