Efficacy of a recovered wash water plant in removing cyanobacteria cells and associated organic compounds

Abstract

Cyanobacteria cells enter water treatment plants from the raw water abstracted from surface water destined to supply the water treatment plants. The presence of cells might interfere with purification processes such as coagulation and flocculation and may subsequently result in the release of taste and odourous compounds. This study is aimed at determining the efficiency of a Recovered Wash Water Plant (RWWP), in removing cyanobacteria cells and associated organic compounds at three stages of treatment, namely raw water, after sedimentation and after filtration. Concentration outcomes were statistically analysed to determine removal ability of the RWWP. The cyanobacteria genera Microcystis, Anabaena and Oscillatoria were detected in the three sampling points (raw water, after sedimentation and after filtration) selected. The organic compounds detected included geosmin, 2-methylisoborneol (2-MIB), and a cyanotoxin, microcystin. It is recommended that the effectiveness of the RWWP should be investigated seasonally during further research