Biological flocculation reactors, namely industrial installation where a physico-chemical reaction takes place in the presence of one or more reagents, namely flocculation polymers and/or coagulants designed to be used in apparatus, devices and installations (static or mobile) intended for water supply, treatment, purification and filtration, for the purification of wastewater or rendering water drinkable; apparatus, devices and installations (static or mobile) designed for water supply, treatment, purification and filtration, especially apparatus, devices and installations (static or mobile) designed for rendering water drinkable; apparatus, devices and installations (static or mobile) for treating wastewater, especially apparatus, devices and installations (static or mobile) for the purification of urban and industrial wastewater, especially apparatus, devices and installations (static or mobile) for wastewater purification by clarification, flocculation and settling