Use of Water Hyacinth in Tertiary Treatment of Domestic Sewage

Abstract

The objective of the present paper is the verification and quantification of the reduction of phosphorus with the use of water hyacinths in tertiary treatment of domestic sewage. Secondary effluents from a small treatment station were run through a series of four tanks containing water hyacinths. Measurements and analyses were conducted in order to verify reduction of nutrients in the final effluent. Results showed removal up to 88% orthophosphates (leaving 0.21 mg/l) for an average detention time of 5.44 days. The average flow was 3.3 m3 per day. These encouraging results suggest the practical value of the method when there is the need of tertiary treatment for the sewage of small communities.