FLOTATION SYSTEMS

Flotation is a process used to separate floatable contaminants, either solid or liquid, from water by injecting fine air bubbles. These bubbles adhere to the particles, which then float. The efficiency of this process depends on the density and concentration of suspended particles, size of bubbles and volume of injected air.

°    DISSOLVED AIR FLOTATION (DAF) SYSTEM

A DAF system is governed by the principle of solubility of air in water as a function of pressure. A portion of the treated water by the DAF unit, close to 25% of the stream, passes through a saturator tank that dissolves air into the water by injecting compressed air at high pressure. The air-saturated water is recycled into the flotation unit after a pressure drop down to atmosferic conditions, which causes the release of many micro-bubbles that adhere to the suspended contaminant particles of the raw water. The buoyant force of the bubbles-particle system is enough to cause pollutants to float continuously in order to be collected by a mechanical system.

°    INDUCED AIR FLOTATION (IAF) SYSTEM

In the IAF units, air is injected in the form of micro-bubbles to the process inlet. These bubbles are generated by a dual system of eductors and a disk-impeller diffuser. The latter has several fine holes on its perimeter to allow the diffusion of ultrafine air bubble, ranging from 10 to 100 microns in diameter. Both, eductor and disk-impeller diffuser, feature an adjustment system that lets the user control the size of the particles and the volume of injected air according to the needs of the process.

The design of the IAF units of TECNIAGUAS® prevents clogging of the bubble-generation mechanisms, thus avoiding downtime for this reason.

 º    INDUCED GAS FLOTATION (IGF) SYSTEM

The IGF system is an interesting option for the treatment of produced water in the oil industry. There are cases when the air injection is not recommended because of the risk of explosion in a hydrocarbon-rich environment, besides the fact that a high level of dissolved oxygen in the reinjection water may have adverse effects on the production equipment, either on surface or sub-surface, or on the geological formations. The IGF units use the produced and recirculated gas to generate the micro-bubbles in flotation process.

TECNIAGUAS® IGF units use a special eductor system operated by one or more recirculation pumps with online static mixers and flow straighteners to introduce gas into the water. The float discharge, composed by oil and suspended solids, is controlled by interphase densimeters that control the opening, closing or adjusting of the discharge valves through a PLC.

º    SUSPENDED AIR FLOTATIO (SAF) SYSTEM

SAF units use a bubble generator aided by a surfactant. This compound coats the generated bubbles and allows them to bind electrostatically to the oppositely charged polymer particles contained inside the flocs. This property of the SAF systems allows upflow rates up to 8 gpm/ft2.