Comprehensive treatment method for oily sewage in oil field

Abstract

The invention relates to a comprehensive treatment method for oily sewage in an oil field. The comprehensive treatment method sequentially comprises an electro-catalysis treatment step, a flocculating settling treatment step, an iron-carbon micro-electrolysis step, a Fenton advanced oxidation step, and a fine filtration treatment, thus obtaining clean water finally. According to the method disclosed by the invention, emulsified oil, suspended matters and COD (Chemical Oxygen Demand) in the sewage of the oil field are effectively removed by using the electro-catalysis treatment step, the flocculating settling treatment step, the iron-carbon micro-electrolysis step, the Fenton advanced oxidation step and the fine filtration treatment, and the water quality of the treated sewage can reach relevant provisions of Comprehensive Sewage Discharge Standard GB8978-1996 and Environmental Quality Standards for Surface Water GB3838-2002.

Description

Technical field: [0001] The invention relates to the field of chemistry, in particular to sewage treatment technology, in particular to a comprehensive treatment method for oily sewage in oil fields. Background technique: [0002] During the exploration and development process of oil fields, drilling sewage, acidizing sewage, fracturing flowback fluid and other sewage are produced. [0003] Drilling sewage is mainly a mixture of drilling fluid, petroleum, drilling cuttings, etc. Its composition is complex and contains various components in drilling fluid, such as clay, organic polymers, oils, inorganic salts, drilling cuttings, drilling fluid additives, etc. In recent years, with the modification of drilling technology and the application of new low-solid and solid-free drilling fluids, the content of chemical oxygen demand has increased, which has brought great difficulties to the treatment of drilling waste. [0004] 1) Composition and hazards of drilling sewage [0005]...

AI Technical Summary

Problems solved by technology

[0017] 1. High pH value, high concentration of soluble salts and petroleum substances will affect the soil structure, inhibit and harm plant growth;

[0018] 2. Heavy metal elements such as Cr, Hg, Cd, Pb, and organic substances and polymers that are not easily degraded by plants enter the food chain and accumulate in animals and plants, endangering human health and life safety;

[0019] 3. If it enters into rivers, oceans or infiltrates into strata, COD, chroma, suspended solids, petroleum volatile phenols, sulfides, metal ions, etc. will seriously exceed the standard, affecting the normal growth of aquatic organisms and polluting groundwater

However, the oil field contains a large amount of COD in the comprehensive sewage, and this kind of COD mainly exists in the form of high molecular polymers such as polyacrylamide, hydrolyzed polyacrylonitrile ammonium salt, sulfonated lignite and sulfonated asphalt. The existing technology is extremely difficult Degradation, and sewage is usually biologically toxic, making it difficult to apply biological treatment methods

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