A large amount of wastewater will be produced in the production process of electroplating plants. Untreated discharge of waste water will cause great loss of water resources, shortage of water resources, serious damage to the environment, and is not conducive to the sustainable development of electroplating enterprises. At present, most electroplating plants adopt zero wastewater discharge technology, which can help electroplating enterprises to better treat water and achieve zero wastewater discharge. “ Zero discharge of electroplating wastewater ”The term is often used in the approval opinions of relevant departments on new, reconstructed and expanded electroplating projects, environmental protection work reports and articles in various surface treatment magazines. Its frequency is unprecedented. However, at this stage, is there any enterprise that realizes zero discharge of electroplating wastewater? The conditions, scope, basis, standards and implementation scheme of zero discharge technology for electroplating wastewater are the problems that must be seriously considered and treated in the electroplating industry at present.
The zero discharge of electroplating wastewater refers to the zero discharge of all wastewater in the electroplating workshop. However, in this kind of wastewater, there are many kinds of pollutants with very complex components, including heavy metal ions and cyanide ions, as well as various complexes, additives and a large number of acids, alkalis, salts, organics and suspended solids. At the same time, various pollutants in wastewater interact to produce pollutants that are more difficult to degrade and remove. Electroplating wastewater is a change of discharge mode, not a zero discharge electroplating wastewater in the true sense. On the contrary, if the zero discharge of electroplating wastewater is realized, new electroplating enterprises, including the newly built electroplating industrial parks, do not need to set up electroplating wastewater discharge outlets.
The electroplating industry has rectified the wastewater treatment system and achieved zero discharge of electroplating wastewater. Realization mode of zero discharge of electroplating wastewater:
1. First of all, enterprises are required to adjust and improve production, save water and improve the recycling rate of production water, carry out separate pre-treatment for various kinds of wastewater, and try to reduce the amount of end treatment of wastewater.
2. The existing wastewater treatment system was rectified. The wastewater treatment system uses the traditional chemical precipitation process, which is technically feasible. However, due to the operation of the treatment system for many years, the zero discharge of electroplating wastewater needs to update the equipment and further improve the degree of automation.
3. A new electroplating wastewater reuse system will be built, so that the wastewater that meets the discharge standard will be treated by the reuse system and reused in the electroplating production line. In order to save water in production, the enterprise has taken effective measures, such as adjusting the position of plating tank and rinsing tank; Adjust the concentration of the plating bath to the most appropriate level; Adopt counter current flushing and spray flushing; The waste water that meets the discharge standard after treatment is directly recycled to the pre-treatment production unit. Through this series of measures, the discharge of electroplating wastewater can be reduced by 33%. In addition, through the rectification of the wastewater treatment system, the treatment effect of wastewater can be guaranteed to reach the standard stably. Therefore, the focus of the work is on the design and implementation of the recycling treatment system.
Because the mathematical concept of zero is quite rigorous, and zero is zero. Moreover, the existing wastewater treatment technology cannot completely remove all the heavy metal ions in electroplating wastewater, and there is always a little bit of it (it is tiny and much lower than the national discharge standard). Therefore, it is impossible to achieve zero discharge of heavy metal ions in electroplating wastewater at present. At best, it can only be said to be close to zero or close to zero discharge. But zero emission is still a direction and a goal. It can motivate us to work hard and strive. Although there is a long way to go, it will be achieved one day.
