Experimental Study On Algae-laden Lake Water For Water Supply By Ultraviolet Pretreatment

Based on summery of algae removal technology both home and overseas, ultraviolet-c was adopted to pre-treat the water from East Lake of Wu Han. The results show that: (1). Ultraviolet-c is valid to pre-treat the algae-laden water, 2.5mW/cm2 shine 6 min can reach equal effect with pre-chlorination after floatation. (2). Intensity and time both have an effect on algae removal rate. Increasing intensity can improve algae removal rate. But when intensity slightly increased,algae removal rate is not rised all the time but has a breakpoint. (3).After radiation of UV,turbidity rises slightly,DO ,CODMn and pH all reduce.Turbidity rising is due to algae pieces. DO reducing is due to produce of ROS. COD reducing is due to UV oxidation. UV can infect algae's activation,and release CO2,so pH reduces. (4).Ultraviolet radiation can decrease the consistency of microcystin-LR in original water,500 μW/cm2 is better than 2500μW/cm2,because with higher intensity, algae cell will break and release more cystic microcystin. (5).With UV thchnology, chlorine amount and reaction time are both lower in the whole treatment and the point of chlorine reaction is also changed, so that consistency of chloroform is lower than pre-chlorination technology.After ultraviolet pre-treatment, consistency of chloroform is undetectable but peak area of chloroform is increased. it is due to product's activation. The innovation of the paper is that: operative experiment of UVC in water supply treatmenmt for algae pretreatment is for the first time.Divide UV dose into Intensity and radiation time, and analyse how they affect algae removal.