Performance and backwashing efficiency of disc and screen filters in microirrigation systems

The performance of three filtration systems (screen, disc and a combination of screen and disc filters) used in microirrigation systems and their automatic backwashing efficiency were studied at inlet pressures of 300 and 500 kPa. The filters were used for more than 900 h with a biological effluent. The physical parameters of the effluent such as turbidity, total suspended solids (TSS) and number of particles were not affected significantly by the different filtration systems at both pressures. Automatic backwashings were classified as being inefficient depending on the value of the initial head loss across the filter after a backwashing took place. The number of filter backwashings required for the screen filter was reduced at 500 kPa, especially due to an increase in efficient backwashings at this inlet pressure. Filtered volume was significantly larger at the beginning of the experiment than after 800 operation hours. The disc filter at both 300 and 500 kPa consumed more water for backwashing than the other filtration systems.