Screen filtration in seawater pretreatment: A pilot trial of the Forsta Filter

摘要

This project set out to design, build and monitor a pilot trial of the self-cleaning ninety series Forsta Screen filter using polished seawater as the feedwater. The trial’s task was to investigate if a five micron self cleaning screen filter can be an effective technology when used near the end of the seawater pretreatment stream found in a conventional seawater reverse osmosis desalination plant. To assess the performance of the screen filter several key parameters were identified including backwash frequency, silt density index testing, turbidity, and pressure. The project originated from the desalination industry’s desire to look for alternative fine filtration technologies away from the commonly used cartridge filters. This project also outlines the scalability of the filter in an industrial setting with comparisons to the cartridge filters found at the Perth Seawater Desalination Plant (PSDP).udud The design required the filter to treat seawater from the Perth Seawater Desalination Plant, with the testing to occur at the National Centre of Excellence in Desalination Australia (NCEDA) in Rockingham, Western Australia. The trial was to last up to 6 weeks during the teaching period. The project faced several unexpected issues in implementing the design over the semester and unfortunately could not fulfill the requirement to conduct the pilot trial within this time. However preliminary testing was completed which confirmed the effective operation of the filter system. Primary objectives for the test were to see if the system design fulfilled its function and verify if certain parameters were attainable in regards to pressure, flow rate, and backwash cycle. The feedwater was brackish groundwater. Results showed: the filter system operated effectively; attained a system flow rate of 5 kiloliters per hour; attained the minimum system back pressure of 40 PSI; and successful automation of the backwash cycle and system. ududFurther work is anticipated to be carried out after the semester to gain closure on the project.