Influence Factors Analysis And Design Parameters Optimization Of Perforated Air-lift Discharge Sludge

Air-lift pump has been widely used in some wastewater treatment plants to lift wastewater or activated sludge because it has many advantages,such as simple mechanical structure,low investment and maintenance cost.However,there are some problems of the device that the discharge sludge is not uniform and the efficiency is low.Therefore,it is necessary to improve the typical air-lift device to improve sludge discharge ability.According the perforated sludge discharge pipe and typical air-lift pump,the concept of perforated air-lift device was proposed.The effects of hole diameter,air flow rate and submergence rate on the sludge discharge ability of perforated air-lift device and the relationship between hole diameter and sludge discharge uniformity were analyzed.At the same time,the comparison was made with the typical air-lift device.In addition,the improvement of perforation distribution and air-injection method are studied.And provide the theoretical basis for the use of perforated air-lift device.The results show that volume of discharge sludge and efficiency are linearly related to hole diameter and submergence rate.The volume of discharge sludge increases with the increase of the air flow rate at first and then remains.The efficiency first increases with the increase of air flow rate and then decreases.Compared with typical air-lift device,the results showed that when the perforation diameter is 22 mm,discharge sludge capacity of perforated air-lift is the same as that of typical air-lift;perforation air-lift discharge sludge device uniformity are significantly greater than the typical,and sludge discharge uniformity can improve though reducing hole diameter.By optimizing perforation distribution to improve the discharge sludge capacity of perforated air-lift,it can be found that the volume of discharge sludge increases about 20%,efficiency increases about 10%,and the sludge discharge uniformity is greatly improved.The effect of air-injecting methods on air lifting performance is studied by changing the numbers of airflow nozzles to test the volume of discharge sludge,lifting efficiency and sludge discharge uniformity.The results show that the volume of discharge sludge and lifting efficiency are best when used the arrangement of three holes.The change numbers of airflow nozzles cannot improve the sludge discharge uniformity.