Utilization of Sour Disposal Water for Irrigation and Plant Usage

ADNOC Sour Gas (ASG) operates the Shah Gas Processing Plant (SGP) which receives and processes sour fluids from the nearby Shah Arab Sour Gas Field. Wastewater streams come from a variety of sources, the largest of which is associated or production water coming from the wells along with the well(s) fluids. There are a variety of impurities found in this water, such as oil, suspended and dissolved solids, COD and BOD, CO2 as well as H2S. The existing wastewater treatment consists of stripper and hydro cyclones to partially treat the wastewater to remove H2S (upto 400 ppm), oil and TDS etc. and sent for disposal into injection well post treatment. ASG is planning to utilize a total of 120 m3/hr disposal sour water (H2S and CO2) for irrigation purpose/ plant internal use post meeting specifications while limiting H2S (below detectable limit), TDS (300 mg/l), COD (50 mg/l), Oil (0.5 mg/l) etc. Along with the selected consultant, ASG explored multiple process schemes; Fenton's & Ozonation process. Fenton's process is an effective chemical oxidation technique used to remove hydrogen sulphide and other organic pollutants from sour water in wastewater treatment. It involves the use of iron catalysts and hydrogen peroxide (H2O2) to generate hydroxyl radicals (∙OH), which are highly reactive and capable of breaking down H2S into harmless compounds. Ozonation is a powerful oxidation process employed to eliminate both the hydrogen sulphide (H2S) and COD from industrial wastewater, converting it into less harmful sulphate ions, improving overall wastewater quality and mitigating environmental impact. Ozonation presents notable advantages over Fenton's oxidation process for H2S removal from gas streams. Firstly, ozonation operates without the introduction of additional chemicals, simplifying the treatment setup. Secondly, its oxidation efficiency is higher, ensuring comprehensive H2S conversion without generating secondary by-products. Thirdly, ozonation produces less sludge, minimizing waste disposal concerns. Moreover, its resistance to pH fluctuations makes it adaptable to diverse gas stream conditions. Collectively, these benefits position ozonation as a superior choice for efficient, streamlined, and environmentally conscious H2S removal. This paper reviews options for sour water treatment process in addition to existing stripper configuration to make it fit for irrigation and / or plant internal usage. It presents a comparison between the two processes in the selection process which includes pilot plant results with product specifications and units involved in the treatment process.