Depth Of Processing Drilling Wastewater By Oxidation

As one kinds of special industrial waste-water produced in the drilling operation process, drilling waste-water can be regarded as combination of diluted drilling mud and derivative of oil, and therefore one of the primarily contaminative sources in oil-field. Through analysis towards the source, water quality characteristic, current treatment condition and the common methods for water treatment, the coagulating method, as the first step method, was employed to treat the water in our study. The best coagulating condition for the treatment was determined through lab-scale experiments designed by orthogonal method, when pH value was 7,adding an inorganic flocculation Al2(SO4)3 deal 1200mg/L and 10mg/L high polymer flocculation PAM in turn, and then mixed and blended them evenly. Static delaminating, the pH value being 7 was obtained to above water in bright yellow , the value of CODcr falls from the 1376 mg/L of raw water to 528 mg/L, and the rate of the removal of the wastewater rate is 60 percent or so. Then, further treatment, with oxidization and biochemical treatment, to the above waster water was available. The study focused on investigating the feasibility of handling the water in ClO2 oxidzation, its function mechanism and the optimal treatment condition. Based on the experiments, the optimal treatment condition was obtained as follows: The value of pH is 3~4, the dosage of the ClO2is 0.6 g/L, respond time is 1h. After ClO2 oxidzation treatment, no obvious color for the waster water was observed, the value of CODcr declined to l40 mg/L, and the removal rate is 73.5 percent approximately. After that , the biochemical slug treatment method was implemented to the two-step treated waster water, after 8 hours treatment, the value of the water's CODcr is 80 mg/L ,and the quality of the treated water already meet the Water Quality (I) of Integrated Wastewater Discharge Standard (GB8978-1996). Based on the lab-scale experiments, the optimizing work towards the combination of aforementioned three treatment methods was carried out and the optimal technical was determined as follows: "the coagulation --> ClO2 oxidzation --> activated sludge biochemical treatment".