Pretreatment method for ammonia-containing high hardness wastewater

Abstract

The invention relates to a pretreatment method for ammonia-containing high hardness wastewater. The method is characterized in that two inlets of a static mixer are respectively connected with a wastewater pipeline and a Na2CO3 solution conveying pipeline, the outlet of the static mixer is connected with a separator, the bottom outlet of the separator is connected with a sludge discharge pipeline,and the top outlet of the separator is connected with the inlet of a settling tank; a first settling trough and a second settling trough are arranged in the settling tank side by side, the bottom outlet of the first settling trough is connected with the sludge discharge pipe, and two inlets of the first settling trough are respectively connected with an alkali lye conveying pipeline and a reagentconveying pipeline; the bottom outlet of the second settling trough is connected with the sludge discharge pipeline; the top outlet of the second settling trough is connected with an ammonia washingtower, and the top inlet of the second settling trough is connected with the discharge port of the ammonia washing tower; the washing liquid inlet of the ammonia washing tower is connected with a first return pipeline, and the first return pipeline is connected with the qualified wastewater discharge port of a stripping system; and the outlet of the stripping system is connected with the first return pipeline and a biochemical treatment device.

Description

technical field [0001] The invention relates to the field of wastewater treatment, in particular to a pretreatment method for ammonia-containing high-hardness wastewater. Background technique [0002] The existing high-ammonia-nitrogen wastewater treatment method usually uses 20wt% NaOH solution to adjust the pH value of the wastewater to above 12, and at the same time, the fixed ammonium salt in the wastewater is decomposed into free ammonia to achieve the purpose of separation from the wastewater. Due to the large consumption of NaOH solution required by this measure, the operating cost and energy consumption of the device are high; in addition, NaOH solution can also reduce the concentration of calcium and magnesium ions in wastewater, that is, to achieve the purpose of reducing the total hardness in the system, but the generated Ca(OH ) 2 The solution is a slightly soluble substance. Only by using gravity sedimentation to remove particles and suspended solids in wastewa...

AI Technical Summary

Problems solved by technology

The acid concentration is high and the dosage is large, resulting in a large amount of fresh water consumption and high energy consumption; and the use of high-concentration acid solution for pH reverse adjustment is likely to cause large fluctuations in the pH value of gray water, which poses a safety hazard to the downstream biochemical treatment equipment. There are also corrosion problems in the pipelines that transport gray water to downstream devices, and the risks of production operation and maintenance are high; and the addition of a large amount of fresh water increases the load on the downstream biochemical treatment system

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