Ultraspin Technology installed an oily water treatment facility for their client, Rio Tinto to replace an existing coalescing plate pack system that was unable to meet the required TPH discharge standards of 20 mg/L.
Ultraspin Technology supplied an ES25 oily water separator, an S2 skimmer with level switch and recycle function; and a 2,000L oil collection/ decant tank.
The skid mounted Ultraspin system comprises of an Ultraspin ES25 (25m³/hour) oily water separation unit with a helical rotor pump and strainer assembly, and is being used to remove oil, grease and solids from the Central Attenuation Sump.
The fluid properties of the process effluent water that are most important for the performance of the Ultraspin separator include oil water density difference, oil droplet size, water temperature, and water viscosity.
Oily water effluent is drawn through a single floating skimmer from the Central Attenuation Sump (CAS). From the Ultraspin oil skimmer, the oily water flows to a debris strainer on the separator skid, where the strainer removes large debris and particles to protect equipment. The back-up strainer inlet and outlet pressure should be observed since cleaning of the strainer is required when the delta pressure is greater than 50 kPa.
A progressive cavity pump provides the pressure to drive the fluid through the Ultraspin separator. A pressure switch is included to shut down the Ultraspin feed pump if it detects an abnormal state (high or low pressure).
This pump feed pressure creates a strong vortex, resulting in a centrifugal force that separates the oil droplets from the water. The oily wet solids will also be affected by the vortex. Separated oil and smaller oil wet solids will go out with the reject stream, while treated clean water is sent to the evaporation pond.
The separated oil (with some water) is sent to the wet oil and sludge collection tank for further processing. The concentrated oil rises to the top of the tank due to its lower SG in comparison with that of water. The oil rich layer at the top of the tank is drawn from the liquid surface and collected in the dry oil collection bulky cube. The remaining water is decanted from the bottom of the collection tank and returned to the start for re-processing.