1. Polyaluminium Chloride (PAC): Highly efficient flocculation and rapid precipitation, especially effective at removing phosphates. Widely applicable to various industrial wastewaters, it is particularly effective at treating suspended particles and some heavy metals in steel mill wastewater.
2. Polyacrylamide (PAM): Available in anionic, cationic, and nonionic types, cationic types are particularly effective at flocculating negatively charged suspended solids in steel mill wastewater, accelerating sludge dewatering and improving treatment efficiency.
3. Iron Salts (such as ferric chloride and ferrous sulfate): Through electrical neutralization and bridging, they aggregate pollutants and are particularly effective at removing heavy metal ions (such as nickel and zinc) and organic matter. They are often used in advanced treatment processes.
4. Aluminum Sulfate: Low-cost, reacts with phosphates to form a precipitate, and is suitable for steel mill wastewater with high phosphorus content. However, it is significantly affected by pH and requires additional pH adjustment.
Key Points for Use:
1. Select the appropriate agent based on water quality (such as suspended solids concentration and heavy metal types). Combinations (such as PAC + PAM) can be used to enhance effectiveness. 2. Control the dosage and reaction time. Typically, rapid stirring is performed in a mixing tank to disperse the reagent, followed by slow stirring in a flocculation tank to form flocs, and finally, sedimentation and separation.
3. Regularly monitor water quality changes and adjust the reagent ratio to ensure that indicators such as heavy metals and suspended solids meet standards.
