Treatment process for wastewater from N-(Phosphonomethyl)iminodiacetic acid production

• Main Authors: LI ZHUQUAN, QING WEIPING, WANG GUOCHENG, CUI WEIDONG, YANG HUA
• Format: Patent
• Language: Chinese; English
• Published: 13.05.2009
• Subjects: CHEMISTRY; COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM,RUBIDIUM, CAESIUM, OR FRANCIUM; INORGANIC CHEMISTRY; METALLURGY; TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE

The invention discloses a method for treating PMIDA (N-(phosphonomethyl)iminodiacetic acid) production wastewater, which comprises the following steps: 1) the PMIDA production wastewater is sent into equipment with a compound evaporator and a vacuum system, and is separated into a saturated concentrated solution containing sodium chloride and evaporable water at a steam pressure of between 0.1 and 0.4MPa and a vacuum degree of between 0.05 and 0.08MPa; the concentrated solution containing the sodium chloride is cooled to crystallize the sodium chloride; and the solid-liquid separation is performed; 2) separating medium is sent into a curing container, a curing agent is added, and innoxious solid mud and a filtrate are obtained after the washing and filtration; 3) after the evaporable water and the filtrate are mixed, a neutralizing agent is used to adjust the pH value to between 6 and 8; 4) an oxidant is added in neutralized wastewater for oxidation; and 5) a treated oxidized liquid is aerated and then enters