Process for water purification using flocculation and biological filtration

摘要

The invention is directed to a process for purifying pre-treated wastewater and surface water, which process comprises adding a flocculating agent and/or a carbon source to the said wastewater or surface water and subsequently feeding the wastewater or surface water to a biological filter, whereby the water is fed in downward flow through a filtration basin, having substantially only GAC as the filter medium, which filter is further provided with a system for removing a surface layer of the filter by suction.