Does anionic polyacrylamide improve the coagulation–flocculation process?

The use of anionic polyacrylamide had little effect on this cost but improved the coagulation–flocculation process, leading to a significant increase in the settling speed and reduction in the volume of sludge produced. Table 7.

Which polyacrylamide coagulants are used as flocculants?

Soluble chemical oxygen demand. Alum and PACl were used as coagulants and very high molecular weight cationic polyacrylamide (C-PAM), Organpol 5415, with low charge density and high molecular weight anionic polyacrylamide (A-PAM), Chemfloc 430A, with high charge density were used as flocculants.

Can anionic polyacrylamide be used as coagulant aid with ferric sulphate and polyaluminium chloride?

It is important to point out that the optimal coagulant dose can be reduced when anionic polyacrylamide is used as coagulant aid with ferric sulphate and polyaluminium chloride, thus decreasing treatment costs. 3.10. Mechanisms of the process

What is the coagulation speed of anionic polyacrylamide?

Coagulation speed: 200 rpm. Flocculation speed: 20 rpm when the coagulant was used alone and 40 rpm when anionic polyacrylamide is added, since the flocs formed were larger and heavier and tended to settle at the lower speed. The influence of the settling time was also studied, the duration of the experiments being fixed at 60 min in all cases.

What are the advantages of anionic polyacrylamide?

The use of anionic polyacrylamide increases the flocculation efficiency of the coagulant, increasing the settling speed, reducing the amount of coagulant required for the treatment and lowering the cost of the coagulation–flocculation process. This work was financially supported by a grant from the Ministry of Education and Science of Spain.

Why is polyacrylamide used as a flocculant?

Polyacrylamide (PAM) is a commonly used polymeric flocculant because it is possible to synthesize polyacrylamides (PAMs) with various functionalities (positive, neutral, or negative charge) which can be used to produce a good settling performance at relatively low cost.