Is polyaluminium chloride better than polyelectrolyte – alum-based coagulation?

At the Barekese Water Treatment Plant in Ghana, an alternative, the polyelectrolyte – polyaluminium chloride (PAC) is also used in coagulation but limited information is available on the operating conditions required to achieve better performance than alum-based coagulation.

Does polyelectrolyte –polyaluminium chloride Formance improve coagulation performance in water treatment?

At the Barekese Water Treatm ent Plant in Ghana, an alternative, the polyelectrolyte –polyaluminium chloride formance than alum-based coagulation. The aim of this study was to determine the optimal coagulant dose, mixing speed and operating pH for enhanced performance in water treatment.

Why are aluminium based polymers used in water treatment?

These shortfalls in the use of alum have led to the synthesis of improved, aluminium-based polymers, which have been used extensively, over the few last decades, for treating water due to their high efficiency at lower dosages, and wider pH and temperature application ranges (Sahu & Chaudhari 2013).

How should coagulation pH be matched to raw water alkalinity?

PACl basicity should be matched to raw water alkalinity, so that coagulation pH is as close as possible to the pH of minimum solubility of the coagulant. The solids separation process used for treatment was also found to be important for coagulant selection.

What are the disadvantages of alum coagulant?

Water Practice and Technology 1 October 2021; 16 (4): 1215–1223. doi: Alum, the predominant coagulant in conventional drinking water treatment schemes, has various disadvantages including the production of large volumes of sludge, lowering water pH (requiring pH adjustment using lime), limited coagulation pH range of 6.5 to 8.0, etc.

Does raw water turbidity affect coagulation?

Raw water turbidity and NOM did not influence the type of coagulant that was most effective. Raw water alkalinity, as it relates to the pH of coagulation, was found to be very important for choosing one coagulant type over another.