Acid wastewater mainly comes from steel mills, chemical plants, dyestuff plants, electroplating plants and mines.
The mass fraction of an acid varies greatly, with the low less than 1% and the high more than 10%.
Alkaline wastewater mainly comes from printing and dyeing factories, leather tanneries, paper mills, oil refineries and so on.
Some of them contain organic or inorganic bases.
Some have a mass fraction of more than 5%, some less than 1%.
In addition to acid and alkali, acid and alkali waste water often contains acid salt, alkali salt and other inorganic substances and organic matter.
Acid - alkali waste water has a strong corrosive, it needs proper treatment before it can be discharged.
Governance, acid and alkali waste water is a principle: (1) the high concentration of acid and alkali waste water, priority should be given to recycling, according to different technical requirements, water quality, water quantity and for the factory or regional scheduling, try to reuse: such as repetitive use have difficulty, or the concentration is low, water amount is larger, can adopt the method of enrichment recycling alkali.
(2) low concentration of acid and alkali wastewater, such as the cleaning water of the acid washing tank and the washing water of the alkali washing tank, shall be neutralized.
For neutralization, the principle of waste treatment should be considered first.
For example, acid and alkali wastewater can be neutralized with each other or by using waste alkali (slag) to neutralize acid wastewater, and by using waste acid to neutralize alkaline wastewater.
In the absence of these conditions, a neutralizer can be used.