METHOD FOR CLEANING SULPHIDE-ALKALINE WASTES Russian patent published in 2012 - IPC C02F1/24 C02F9/14 B01D3/38 C02F103/18 

FIELD: oil and gas industry.

SUBSTANCE: hydrocarbons are removed at the stage of waste flotation cleaning. Then water waste with pH within 7.5 to 12 units is discharged from flotation cleaning, perform reactant treatment by carbon-dioxide gas and sulphur acid with its following supply into stripping-tower equipped with live reflux at the top or circulating upper refluxing and direct supply of water vapour into the cube. Note that carbon-dioxide gas and waste is supplied into agitator equipped with the nozzle that depending upon the quality of initial waste by sulphide sulphur operates either in saturation mode, when carbon-dioxide gas consumption is maintained from condition of obtaining balanced gas saturation of the waste or adsorption with stripping gas discharge from the agitator and its supply directly to the column. Discharged waste cleaned from sulphide sulphur and ammonia nitrogen is directed to the biological cleaning. Acid gas is directed to obtainment of elemental sulphur.

EFFECT: method provides optimal conditions of water wastes cleaning from ammonia nitrogen by sulphide sulphur content that meet the requirements of biological treatment.