1. Explain the colloidal particles in sewage and drinking water.
Answers
Answer:
The most common and practical method of removing colloidal particle is by chemical coagulation. This is a process of destabilizing colloids, aggregating them, and binding them for ease of sedimentation. It involves the formation of chemical flocs that absorb, entrap, or otherwise bring together suspended matter, more particularly suspended matter that is so finely divided as to be colloidal. The chemicals most commonly used are alum, copperas, ferric sulfate, ferric chloride, and chlorinated copperas. The process of chemical coagulation involves complex equilibria among a number of variables including colloids of dispersed matter, water or another dispersing medium, and coagulating chemicals. Driving forces—such as the electrical phenomenon, surface effects, and viscous shear—cause the interaction of these three variables. Coagulation by neutralization of electrical charges can be accomplished by either lowering the zeta potential of the colloids or by flooding the medium with an excess of oppositely charged ions. A large number of compounds that are not amenable to other types of treatment may be removed from wastes by adsorption.