Physico-chemical processes are particularly suitable for wastewater treatment that are not biodegradable. Also they are used in the partial treatment of water organically degradable, being interesting to use as primary treatment or phase of subsequent biological processes.

The process mainly consists of the addition of coagulants and flocculants to the water to be treated, with a neutralization (if necessary) to proceed later with the precipitation or flotation of sediments, according to each case.

It is required necessarily to introduce a sludge dehydration system. In general, the specific processes for each type of water require different types of additives and different dosages thereof.