May I ask, where are the salt regulations in the standards for wastewater discharge?

The comprehensive sewage discharge standard does not have a standard limit of salt to control this, in fact, the main impact of salt in the wastewater is still on the subsequent treatment of the impact of the chemical industry to produce most of the organic wastewater are taken to the biochemical treatment, the process is mature, low-cost, but according to the relevant information, in addition to the special cultivation of salt-resistant bacteria, the general biochemical process to deal with wastewater, the limit of salt concentration of about 4000mg / L, high salt leads to the death of bacteria, the biochemical system is difficult to operate normally. Concentration of about 4000mg / L, high salt leads to the death of bacteria, biochemical system is difficult to operate normally.

For this kind of high-concentration wastewater, if you want to really follow the requirements of treatment to meet the discharge standards, is destined to be difficult and high investment. According to personal experience:

If the chemical wastewater concentration is very high, COD reaches tens of thousands or even hundreds of thousands, and the amount of water is not large, suitable for the use of incinerator incineration, incineration temperature of 1100 ℃ or so, but the incinerator exhaust gas must be processed, but also to meet the requirements of the incineration of hazardous wastes and emission standards, and at the same time, because of the high salt content, the need for rinsing, or else the salt is easy to set in the furnace wall. And rinse down who although COD is lower, generally can meet the comprehensive emission standards, but the salt is too high, still can not be discharged directly, only three-effect evaporation to recover salt, therefore, the whole process is more complex, the investment is also too large. Now there is a wastewater granulation incineration treatment system, I think it is better, salt direct granulation, and incineration without wastewater discharge, it is recommended.

If the wastewater concentration is general, the follow-up still have to take biochemical processes, must first desalt, can first gas lift to remove some volatile organic compounds, and then use three-effect evaporation desalination, and then biochemical treatment.

In fact, at present, most of the enterprises for this type of water is used to dilute the post-treatment, mixed with a large number of river water, or even tap water, to reduce the concentration of salts, and then biochemical treatment, but the dilution of the treatment is obviously not in line with the requirements of environmental protection.