Enhanced Coagulation for Treatment of Wastewater from Acid Gas Removal Unit

Amine solutions which are widely used in the gas processing industry for the removal of acid gases frequently become contaminated with amine degradation products, heat stable salts, heavy hydrocarbons and particulates. Amine based gas purification plants generate large volumes wastewater which is the major issue that contribute to the water pollution problems. This is probably due to the fact that, industries consume high amount of process water and chemicals and at the same time, produce high amount of highly polluted discharge water. Due to its harmful effects towards the environment and living organisms, various researches have been carried out to treat these effluents. And there is a need to treat wastewater to suitable standards at relatively low cost without sophisticated advanced treatment processes which have high requirements [1].
There are many processes for wastewater treatment, like coagulation, adsorption and membrane separation. Highly water-soluble amines have not satisfactorily been removed by current physical or chemical treatment of water thus a new approach using coagulation and flocculation was investigated in this study. So, coagulation and Flocculation by being one of the most convenient physical and chemical treatments underlines more on how to make this process efficient in terms economic, residual water quality, and at the same time, to improve the produced sludge so that it will be easily treated or disposed later on.
Diethanolamine contaminated wastewater was treated using the enhanced coagulation method. The experiments had been carried out by varying few parameters like dosage of coagulant (Ferric Chloride), pH, temperature and effect of coagulant aids (lime and bentonite). Series of jar test had been conducted with 3 minutes of rapid mixing at 200 rpm, followed by 30 minutes of slow mixing at 45 rpm and 1 hour of settling process. Afterwards, the solution was tested for DEA level, Chemical Oxygen Demand (COD) and amount of sludge produced.