source:LASEN Environmental Protection release date:2025-12-17 Number of reads:123
1.Poor flocculation performance:If flocculation results are unsatisfactory, the first step is to check whether the dosage is appropriate. A jar test can be conducted to re-determine the optimal dosage by gradually increasing or decreasing the amount added and observing floc formation and settling behavior. Secondly, it is important to consider whether the pH of the water falls within the effective range for the product. If the pH is too high or too low, it may adversely affect the hydrolysis and flocculation process of polyaluminum chloride (PAC). In such cases, adjusting the pH to the recommended range (typically 6–9) can improve flocculation performance. Additionally, water temperature also influences flocculation efficiency. At lower temperatures (below 10°C), the hydrolysis rate of PAC slows down, leading to poorer flocculation. To address this, the water temperature can be moderately increased, a product formulation specifically designed for low-temperature applications can be selected, and/or mixing time can be extended to facilitate hydrolysis and enhance flocculation.
2.Dissolution Difficulty:If the product fails to dissolve completely, this is likely due to improper dissolution methods or unsuitable dissolution conditions. During dissolution, polyaluminum chloride (PAC) should be added slowly and evenly into agitated water to prevent lumping caused by dumping large quantities all at once. It is recommended to use a simultaneous mixing-and-adding approach to ensure thorough contact between the product and water. The temperature of the dissolution water should be maintained between 15°C and 35°C. If the water temperature is too low, the dissolution rate will decrease; if it is too high, product performance may be compromised. The agitation speed should be moderate—typically between 100 and 200 rpm—and the mixing duration should be approximately 20 to 30 minutes. If lumps form during dissolution, stirring time can be extended or agitation speed slightly increased. If necessary, any undissolved lumps can be removed and re-dissolved.
3.Equipment Corrosion:Polyaluminum chloride (PAC) solutions are slightly acidic and may cause corrosion to metal equipment with prolonged use. To prevent corrosion, iron-based containers should be avoided for both storage and dissolution of the product. Instead, containers made of corrosion-resistant materials such as plastic, stainless steel, or ceramic are recommended. Additionally, equipment should be inspected and maintained regularly, and any residual solution on surfaces should be promptly cleaned to prevent prolonged contact that could lead to corrosion. If corrosion has already occurred, affected areas can be repaired using anti-corrosion coatings, or corroded components can be replaced with corrosion-resistant parts.
4.Increased Sludge Production:In some cases, the use of polyaluminum chloride (PAC) for wastewater treatment may lead to an increase in sludge volume. This is primarily because PAC aggregates suspended solids and colloidal particles in the water into flocs during the flocculation process, thereby increasing the amount of sludge generated. To minimize sludge production, the dosage can be moderately reduced while still maintaining effective treatment performance. Alternatively, a PAC product with a higher degree of polymerization—known to generate less sludge—can be selected. Furthermore, optimizing downstream sludge handling processes, such as sludge thickening and dewatering, can also help reduce both the moisture content and overall volume of the sludge.(AI生成)
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