Improving the Performance Of WWTP At Desalter Plant, O.N.G.C. Ltd, Nawagam, Ahmedabad

Abstract

The quality of water cut produced from preliminary treatment of crude oil is one of the most decisive factors for maintaining the productivity of the reservoir by making up the pressure loss caused by oil extraction. This water cut should have oil & TSS concentration as low as possible to keep the perforated region of an oil well clean and productive. A system which runs on the principle of Dissolved Air Floatation system using natural gas in place of air has been designed and run to augment the capacity of the existing WWTP. The system’s performance is better than the DAF system and uses fewer amounts of chemicals to treat the same quantity of wastewater. The DGF system has been checked for treatment of wastewater using alum and a commercially available polyelectrolyte CATFLOC at various concentrations. It has been found out that alum dosing of 200ppm and polyelectrolyte dosing of 10 ppm is best combination for treatment under DGF system. The system gives desired results at ease which are under the GPCB norms.