Pretreatment method for petrochemical wastewater before reuse

Abstract

This disclosure relates to a pretreatment method for petrochemical wastewater before reuse. The method includes: mixing petrochemical wastewater, flocculant, and electrostatic regulator in a high-density tank; the pH of the resulting petrochemical wastewater is 7.0-8.8; after reacting for 1-10 minutes, a softener, alkali, and coagulant aid are added to adjust the pH of the reacted petrochemical wastewater to 9.5-10.6, followed by softening, sedimentation, and solid-liquid separation. The flocculant is an inorganic polymeric flocculant; the coagulant aid contains an organic polymeric coagulant; and the electrostatic regulator contains an agent with the structural formula NH-{R-NH-(CH2CH2O). n -[(CH2CH(CH3)O] m The compound is a ⁻H₂ group, where R is one or two of ⁻C₂H₄⁻, ⁻C₂H₄NHC₂H₄⁻, ⁻C₂H₄NHC₂H₄NHC₂H₄⁻, and ⁻C₂H₄NHC₂H₄NHC₂H₄⁻, where n is an integer from 0 to 50, and m is an integer from 0 to 50, and m and n are not both 0. The method disclosed herein is cost-effective and efficient, capable of removing suspended solids, hardness, some macromolecular organic matter, and water treatment agents from petrochemical wastewater under relatively low pH conditions, while simultaneously reducing membrane fouling problems in subsequent membrane treatment units.

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