The formation of biolayer and the removal efficiency of wastewater by using Biosand Filter (BSF)

Abstract

This research was conducted to study on the formation of biolayer and the removal efficiency of wastewater by using biosand filter (BSF). The BSF has great significance to improve the bio-stability of water quality. The BSF is resulted from a simple construction which requiring only layers of sand and gravel which use mechanical filtration and a bacterial biolayer called schmutzdecke to purify water. The objectives of this research are to study the possibility of biolayer growth in BSF by using real wastewater and to evaluate the removal efficiency of wastewater by using BSF. The growth of the biolayer in the BSF can be determined by the technique of inoculation and gram staining. The characteristics of water sources influence on the possibility of cultivating the biolayer and as a result, large and varied microbial populations may develop. The nature background of the wastewater was studied based on the parameter of chemical oxygen demand (COD), dissolved oxygen (DO) and mixed liquor suspended solid (MLSS). As a result, bacteria species of Bacillus sp. was exist for both Reactor 2 and Reactor 4. The DO value for Reactor 2 was at 6.83 mg/L and 7.85 mg/L for Reactor 4. This shows that with high DO level, Reactor 4 is more effective than Reactor 2 and for MLSS value for Reactor 2 was at 1750 g/L and for Reactor 4 was at 1707 g/L. For the COD removal efficiency of the wastewater, Reactor 4 was found to be more effective than Reactor 2 with higher COD removal efficiency at 82 % compared to R2 at 80 %.