The invention provides a method for treating p-hydroxybenzonitrile production
wastewater. The method comprises the steps of alkali adjustment,
air stripping, absorption,
neutralization, concentration,
centrifugation and the like. On the basis of a traditional
ammonia stripping device, a neutralizing device of
hydrochloric acid and a concentrating device of
ammonium chloride are introduced, the neutralizing device of
hydrochloric acid can directly absorb
ammonia gas generated by the
ammonia stripping device to generate an
ammonium chloride byproduct, and the concentrating device of
ammonium chloride can form high-temperature
water vapor in the process of concentrating an
ammonium chloride solution; and meanwhile, high-temperature water steam is introduced into the ammonia stripping device to serve as a heat source, so that extra
energy consumption required by the operation of the ammonia stripping device is greatly reduced, and the economical efficiency and the
environmental protection property of
system operation are improved. According to the method, only the cheap industrial byproduct
hydrochloric acid is introduced as a new
raw material, so that the value of the byproduct is greatly improved, the economic benefit is integrally improved, meanwhile, high-temperature steam generated in the
ammonium chloride production process can also be used as a heat source of an ammonia stripping device, and the cost is further reduced.