Study on decomposition of pollutants in algae-bloom water and analysis of drinking water safety

  Objective   To conducte xperimental researches on the removal efficiencies of algae, bacteria, NH₃-N and UV254 by ozone(O₃)and stationary chlorine dioxide(ClO₂), and to study the safety of the effluent.

  Methods   O₃ and ClO₂ were used to pretreatalgae-bloom waterin lab test.

  Results   Algae and bacteria could be removed effectively in pre-oxidation by O₃ and stationary ClO₂.Algae concentration in the raw water had little effecton algae removal atchlor ophyll concentration of 22.4~20.4 μg/L.However, algae removal had been affected significantly by pH value.The removal rate of algae increased with decrease of pH value, while the effectof pH value on bacteria removal was notsig nificant.Compared with O₃, stationary ClO₂ could notremove the turbidity and the chroma effectively.Meanwhile, the NH₃-N concentration increased in the water afterthe process of ozonation.The removal of UV254 was greatlyenhanced by ozonation.The for mation of CHCl₃ and CCl₄ could be controlled notonly by O₃ butalso the stationary ClO₂, and the safety of drinking water could be also improved.

  Conclusion   Bo th O₃ and ClO₂ could pretreatalgae-bloom watereffectively and safely.Compared with ClO₂, O₃ was better.