In the treatment of industrial electroplating wastewater, the strengthening of the pretreatment process is crucial to improving the efficiency of the entire treatment system and the removal of refractory pollutants.
First, as a common pretreatment method, chemical precipitation can enhance the effect by optimizing the type, dosage and reaction conditions of the precipitant. For example, for chromium-containing wastewater, the traditional lime precipitation method can be further improved. Using ferrous salt as a precipitant, hexavalent chromium is reduced to trivalent chromium under acidic conditions and then precipitated, which can remove chromium ions more thoroughly, and the removal rate can be increased from about 80% to more than 95%. At the same time, precise control of reaction parameters such as pH value, temperature and stirring speed can make the precipitation reaction more complete and reduce the residual refractory chromium compounds entering the subsequent treatment link.
Secondly, the adsorption method has a unique effect on refractory organic matter and heavy metal ions in pretreatment. Select adsorbents with high specific surface area and special functional groups, such as modified activated carbon, biochar or new polymer adsorption materials. These adsorbents can not only adsorb common heavy metal ions such as copper and nickel, but also effectively remove difficult-to-degrade pollutants such as organic complexing agents in electroplating wastewater. By optimizing the regeneration process of the adsorbent, the treatment cost can be reduced and the reuse rate of the adsorbent can be increased. For example, the combination of thermal regeneration and chemical elution can make the adsorbent recycle for many times, and the adsorption performance can be maintained at a high level.
Furthermore, micro-electrolysis technology can enhance the pretreatment effect. Industrial electroplating wastewater treatment equipment uses iron filings and activated carbon to form a micro-electrolysis system. When wastewater flows through, redox reactions will occur. The dissolution of iron filings produces ferrous ions, which have a reducing effect and can destroy the structure of difficult-to-degrade organic matter in wastewater and improve its biodegradability; at the same time, the generated iron hydroxide colloid has a flocculation effect and can adsorb some pollutants. Reasonable design of the structure, filler ratio and water flow rate of the micro-electrolysis reactor can make the micro-electrolysis process more efficient and significantly improve the removal rate of difficult-to-degrade pollutants. For example, the removal rate of some complex organic pollutants can be increased by 30-50%.
Finally, strengthening the pretreatment process also requires comprehensive consideration of the synergistic effects of different processes. Combine chemical precipitation, adsorption and micro-electrolysis and other technologies to formulate personalized pretreatment plans based on the specific water quality characteristics of electroplating wastewater. Through the complementarity between various processes, it can remove difficult-to-degrade pollutants to the greatest extent, reduce the pressure of subsequent biological treatment or deep treatment units, improve the overall treatment efficiency and stability of industrial electroplating wastewater treatment equipment, ensure that the treated wastewater meets the discharge standards, reduce pollution to the environment, and promote the sustainable development of the electroplating industry.
