Numerous water treatment chemicals can be employed in wastewater processing. Among these,
polyacrylamide is widely recognised as offering excellent value for money in water treatment applications. What considerations should be borne in mind when using polyacrylamide?
First, examine the classification of polyacrylamide products. Based on molecular characteristics, they are categorised as non-ionic, anionic, amphoteric, or cationic. Therefore, selecting the appropriate product type is essential prior to water treatment. Concurrently, it is crucial to understand the characteristics of the water to be treated. For water with a pH value between 5 and 14, an anionic product is required. A pH value between 1 and 8 permits the use of a non-ionic product. Conversely, a pH value between 7 and 14 allows for the application of a cationic product. Given its efficacy as a flocculant, thickener, and liquid drag reducer, among other functions, polyacrylamide finds extensive application in the treatment of industrial wastewater from sectors such as papermaking, petroleum, and coal.
What should be noted when using polyacrylamide products? Dosage and timing are crucial. Addition should ideally be carried out in batches at a slow rate. First, introduce a portion to mix with the water, then after a minute or two, add another portion of the chemical to mix with the water. Generally, it is advisable to add 60% of the quantity first, followed by the remaining 40%. When preparing the solution, ensure the concentration is reduced. Under normal circumstances, anionic products should be prepared at a concentration of 0.1%, while cationic products are best prepared at 0.2%. If the preparation tank is relatively small, a higher concentration may be used, provided it is diluted during application.
Finally, pay attention to the pH level of the water to be treated. If the pH is significantly high or low, adjust the water's pH first before adding the product. When used in conjunction with inorganic products, it is preferable to add the inorganic flocculant first, followed by the amide product. It should be noted that higher molecular weight does not necessarily equate to better performance for amide products, nor does a higher dosage guarantee superior results. Optimal dosage ratios and quantities should be determined through experimentation tailored to the specific characteristics of the water quality. This approach ensures effective wastewater treatment while minimising chemical wastage and reducing operational costs.
