Review of Recent Patents on Coagulation / Flocculation (C/F) Process: Methods and Applications with Emphasis on Phosphates Removal
Athanasia K. Tolkou and Anastasios I. Zouboulis
Affiliation: Department of Chemistry, P.O. Box 116, Aristotle University, GR-54124 Thessaloniki, Greece.
Keywords: Al-based coagulants, coagulation, Fe-based coagulants, flocculation, phosphates removal, tannin-based polymeric
coagulants, wastewater treatment.
The present review describes the most recent patents and outlines the progress made over the last decade in the
field of wastewater treatment focusing on the application of Coagulation/Flocculation (C/F) process, which is mainly used
as primary treatment for the effective removal of colloidal particles and organic matter. Various materials/chemical reagents
have been developed in recent years as coagulation/flocculation agents. Among them are inorganic-based coagulants,
organic-based flocculants, as well as hybrid materials, or tannin-based polymeric coagulants. Furthermore, a recent
patent application for treating wastewater is using nanoparticles of clay as anionic coagulant agent. In many sensitive
catchment areas, the effective removal of phosphorus is also required. Several alternative processes, methods and treatment
systems have been provided in recent patents for lowering the concentration of phosphorus in wastewaters, noting
that the conventional use of alum or ferric chloride for phosphorous removal is rather problematic due to acidity of coagulants,
being added to the wastewater. A coagulation-sedimentation apparatus is specifically designed to treat water at
higher rates and a more recent patent discloses a system for continuous optimization of the relevant wastewater treatment.
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