I. Introduction.
Acid and alkali wastewater is one of the common wastewater in the industrial production process, mainly in the chemical, metallurgy, electronics and other industries. This kind of wastewater contains a large amount of acid or alkali, which causes serious pollution to the environment and poses a threat to human health and ecological balance. Therefore, how to effectively treat acid and alkali wastewater has become an urgent problem to be solved. This paper will analyze the major difficulties of acid and alkali wastewater treatment, and introduce the corresponding process technology solutions, in order to provide reference for related fields.
Second, the major difficulties in the treatment of acid and alkali wastewater.
The high concentration of acid or alkali in acid and alkali wastewater brings great challenges to treatment. Traditional treatment methods are often difficult to meet the processing requirements, and more efficient and stable methods are needed for treatment.
The influence of other impurities in wastewater, acid and alkali wastewater often contains other impurities, such as heavy metal ions, organic matter, etc. The presence of these impurities will have an impact on the treatment effect and need to be treated accordingly.
The treatment cost is relatively high, due to the difficulty of treating acid and alkali wastewater. How to reduce the processing cost on the premise of ensuring the treatment effect is a problem that needs to be solved at present.
3. Process technology scheme for acid and alkali wastewater treatment.
Pretreatment: First, the acid and alkali wastewater enters the pretreatment stage. At this stage, impurities such as suspended solids, grease and other impurities in wastewater are removed through sedimentation, air flotation, filtration and other technologies. This ensures a smooth follow-up process and reduces interference with the subsequent process.
Acid-base neutralization: After pretreatment, acid-base wastewater enters the acid-base neutralization stage. At this stage, by adding an appropriate amount of neutralizer (such as lime, sodium hydroxide, etc.), the pH value of the wastewater is adjusted, so that the acid or alkali in the wastewater can be neutralized with the neutralizer to form salt substances. In this way, the acid or alkali in the wastewater can be removed and the pH of the wastewater can be reduced.
Sedimentation treatment: After acid and alkali neutralization, the salts in the wastewater will form precipitate. At this stage, the salts are separated from the wastewater by sedimentation technology. The sediment can be further treated or disposed of, while the purified wastewater can move on to the next stage of treatment.
Adsorption treatment: After precipitation treatment, the concentration of salts in the wastewater has been reduced, but some trace impurities may still be present. At this stage, the adsorption properties of the adsorbent can be used to further remove trace impurities from the wastewater. Commonly used adsorbents include activated carbon, zeolite, etc. By passing the wastewater through the adsorbent layer, the adsorbent can adsorb trace impurities in the wastewater, thus achieving deep purification of the wastewater.
Membrane separation technology: After adsorption treatment, the impurities in the wastewater have been effectively removed. At this stage, membrane separation technology can be used to further remove trace salts and organics from the wastewater. Commonly used membrane separation technologies include reverse osmosis, nanofiltration, etc. By selecting the appropriate membrane material and operating conditions, the trace salts and organic matter in the wastewater can be effectively separated from the water, so as to achieve deep purification of the wastewater.
Disinfection treatment: After membrane separation technology, salt and organic matter in the wastewater have been effectively removed. At this stage, the wastewater can be disinfected to kill microorganisms such as bacteria and viruses in the wastewater. Commonly used disinfection methods include chlorine disinfection, ozone disinfection, etc.
Discharge or reuse: After the above treatment, the pollutants in the wastewater are effectively removed and the water quality is significantly improved. At this stage, wastewater can be discharged into the environment or reused in the production process, depending on the actual situation. Wastewater needs to be tested and monitored to ensure it meets standards and requirements before it can be discharged or reused.
4. Conclusions and prospects.
The major difficulties in the treatment of acid-alkali wastewater mainly include high acid-base concentration, the influence of other impurities in wastewater and high treatment costs. In view of these problems, the corresponding process technology scheme can be adopted to deal with them. When choosing a treatment method, it is necessary to comprehensively consider factors such as treatment efficiency, cost, and environmental protection. At the same time, with the continuous progress of science and technology, more efficient, environmentally friendly and low-cost acid and alkali wastewater treatment technologies may emerge in the future. Therefore, technology research and development and innovation should be strengthened in related fields to provide more options and possibilities for solving the problem of acid and alkali wastewater.