MIXING STEPS IN WASTE WATER TREATMENT

Coagulation involves adding chemicals to the water to neutralise particle charges, often using ferric chloride or aluminium sulphate.

Polymers are then added for flocculation, which requires rapid mixing.

Polymers are introduced to facilitate particle agglomeration, aiming to create large flocs.

Moderate to gentle agitation is needed to promote floc formation while preventing shear destruction.

The aim of neutralisation is to neutralise the water so that coagulation or flocculation operations can be carried out by adding lime, soda or sodium carbonate.

The pH of the water must be 7. The number of agitations is 4.

Coagulation, flocculation, and neutralization yield sludge with a high organic content, varying in liquidity, necessitating treatment to minimize volume for storage efficiency.

Fermenting organic products generates gas and increases sludge concentration, reducing volume by up to 20%. Digestion tanks, ranging from 2000 to 6000m3, maintain a residence time of 10 to 15 days.