Filtration of Chlorella through Dune-Sand

In order to study processes when effluents from stabilization ponds are used for artificial recharge using suspensions of algae (Chlorella) and a long column filled with dune sand. For the filtration velocities used, ranging from 1 m to 6 m per day, it was found that most of the algae were retained at the upper part of the sand columns, where the increments in head losses were observed. The lower filtration velocities produced larger quantities of filtered water and better filtration efficiency. When a coefficient was introduced to account for algae multiplication, results of the experiments reasonably fitted an equation proposed by Ives for filtration processes. The effect of ion concentration on the efficiency of filtration was clearly shown by changing the salinity of the algal suspension.