Research On Air Flotation Technology Treating Raw Water Of High Algae And Low Turbidity

Based on the raw water of Shenzhen of "Hight Algae and Low Turbidity", the paper studies the treatment effect of dissolved air flotation process. It studies mainly the four parts: the confirm of the parameters of air flotation process; the effect of treatment of air flotation process; the application of ozone-flotation; and the method of acetone distill chlorophyllous-a to count algae.Through studing the different factors of influence of air flotation, we confirm the parameters of our air-flotation equipment treating the raw water of Shenzhen are:the dose of PAC is 1.25mg/L, the treated water is 0.8 m³/h,the retention time is 22.9 minutes, the dissolved pressure is 0.42Mpa, and the amount of air is 200ml/min.Results of the study show that:when the turbidity of raw water is between 3NTU and 32NTU the amount of algae is less than 1.08 x 10⁷个/L, the removal rate of air flotation for turbidity and algae is 89.3% and 92.7% respectively;besides,the average removal rate of air flotation for COD_Mn is 32.6%, the color of treated water is below 20 ,21.2% of TOC is removed at least Compared with sedimentation process, the dose of PAC of air flotation is less, it can reduce the cost of water treatment plant,and it improves the quality of treated water.Ozone flotation combines the chemical character of ozone with physical character of flotation, it is a new process of enhanced air flotaion.Through researching, we confirm the parameters of ozone flotation are:the dose of ozone is between 100 and 300mL/min,the dose of ozone is 0.8-1.0mg/L. Compared with dissolved air flotation,adding ozone can improve water quality,and the effect of preformed ozone air flotaion is better than ozone air flotation.The method of counting algae takes much time, researcher can't obtain the data in time and it delays researcher to analyse. Especially.when the algae is less than 1.0 ×10⁵个/L, it is very difficult to obtain the accurate data.So the paper studies the fluorescence-method of acetone distill chlorophyllous-a, tring to use it to replace the method of the mothod of counting algae.