Sewage treatment system - with alternately rising and falling algal concentration in pond

摘要

A sewage treatment system consists of an anaerobic digestion basin, three biological cleaning stages with trickling filter drums, and an algae pond. The algae concentration is raised in turn to a maximum and then reduced to a minimum by pumping the algae into the digestion basin where the anaerobic conditions kill them. Thsi is a simple and efficient method of extracting nitrates and phosphates from sewage.