Comparison on the duration of career between slow sand filter with conventional cleaning and backwashed slow sand filter

Abstract

Slow sand filter is a water treatment technique for human consumption very old, dated 1804. Despite being old, it continues to have significant utility. The treatment process is based on water purification through the use of sand as filter environment to retain the impurities. The proposal presented is guided in comparing the slow sand filter, between forms of cleaning the filter medium: conventional or backwashing. The conventional way is by scraping the surface of the filter medium, whereas by backwash, is based on the against flow of the filtered water to expand filter medium, with consequent dragging of the impurities that were retained in the filter medium and over the same, so separating the filter medium of impurities. The comparison was due to the duration of the filters filtration career. Despite filter slow with backwash to be considered faster during the clean of the filter medium, the average duration of the filtration career was only 17 days. This may be an indicator that the profile of the filter layer continued enriched with microbial flora, it is required for the following filtration career, while the filter slow conventional cleaning had duration approximate 50 times slower than the filter slow backwashed. The average duration of filtration careers, of the filter slow conventional cleaning was 22 days, so most enduring.