Studiul performanţei biofiltrelor de nisip pentru reducerea contaminanţilor microbieni: coliformi totali, E. coli si nterococi din apa potabilă destinată ţărilor în curs de dezvoltare

Point of view drinking water treatment technology enables those without access to safe water sources to improve the quality of their water by treating it in the home. One of the most promising emerging point of view technologies is the biosand filter (BSF), a household scale, intermittently operated slow sand filter. The major objectives of this research were to: (1) gain an understanding of the hydraulic flow condition within the filter (2) characterize the ability of the BSF to reduce the concentration of enteric bacteria (3) gain insight into the key parameters of filter operation and their effects on filter performance. Between 6 to 8 weeks microbial challenge experiments are reported herein in which the source water was charged to the filter daily. Tracer tests indicate that the BSF operated at hydraulic conditions closely resembling plug flow. BSF performance in reductions of E Coli ranged from 10 -100 to less than 1 MPN(most probable number), after at least 20 days of operation. Total Coliforms reduction were much higher from 200 – 300 to less than 1 and Enterococcs reduction ranged from 12 – 18 to 1 MPN.