Different Parameters Effect on Photoelectrocatalysis for Organic Pollutants Removal from Gasfield Wastewater

In this study, after separating oil and grease from gasfield produced water, removal of organic pollutants has been investigated to reduce its chemical oxygen demand (COD) from 9500 mg/L to the limits of agriculture irrigation. Since the initial electrical conductivity of the wastewater was too high (6300 µS/cm), evaporation process was used to decrease its dissolved solids content. As results of evaporation, electrical conductivity and COD have been reduced to 1100 µS/cm and 750 mg/L respectively. Afterwards, photoelectrocatalysis as an advanced oxidation process was applied to treat distilled wastewater from evaporation step because of COD content of less than 1000 mg/L. In the photoelectrocatalytic method, “boron carbon nitrite nanomaterial” was used as photocatalyst in a coil type microreactor with surface-to-volume ratio of about 3000 m2/m3, which it causes in rapid oxidation of organics. After fabricating the microreactor, the effect of different parameters on COD removal has been investigated. It has been found out that optimum conditions to remove of 80% COD are accordance with pH = 3, potential difference 20 V and electrical conductivity of 2500 µS/cm, so that COD is reached about 150 mg/L which is suitable for agricultural irrigation.