Development and application of a three-grade self-clean on-line filtration system
自洁式三级串联的水样在线过滤系统的研制和应用

Based on the filtration principles of turbidity removal with glass fiber, micropore tube, and ultrasonic assistanted cleaning, a three-grade self-clean on-line filtration system with back-flush function was developed. A screen (first-grade), a filter filled with glass fiber under ultrasonic (second-grade) and a micropore tube (third-grade) were assembled in series and used for the on-line filtration of high turbidity environmental water samples. The removal efficiencies on turbidity of simulative and real water samples were evaluated, and the system was found worked well. Under the optimal conditions, the original turbidity of water samples ranged from 4 to 100 NTU could be decreased below 1 NTU after filtration. Taking the concentrations of typical nutrients (orthophosphate, ammonium, nitrite and nitrate) determined with standard methods as references, the recoveries of four nutrients from water samples treated with the proposed filtration system were found between 85% and 130%, indicating that the system had almost no effect on determining the target substances.