![]() | Only 14 pages are availabe for public view |
Abstract The conventional water resources in Egypt are limited to mainly the Nile I River and groundwater. Egypt is optimizing the use of freshwater and exploring the use of new non-conventional sources of water, such as agricultural drains. Bilbeas and El-Qalyoubia drains are two of the most polluted water streams in Egypt. One of the proposed methods to enhance the drain self-purification capacity is the use of submerged biofilter (SB). Four streams pilot were installed at KP 35.0 of Bilbeas drain, and two streams were installed at KP 12.0 of El-Qalyoubia drain. The experimental work was divided into two stages. Stage ”1” was carried out in Bilbeas drain during the period (December 2005- July 2006). It included four runs, each two runs preceded by start up period. whereas stage ”2” was done during the period (June 2007- July 2007), and included one run preceded by start up period. At Bilbeas drain three of the streams were equipped with three different types of media (pall rings, star shape and gravel) working as SBs while the fourth remained without any media to provide a corresponding reference for the natural purification. The three biofilters had the same total surface area of media -for biofilm growth, the same width, and depth, but differed in length in the flow direction. The four streams were operated at the same time under the same flow rate. Results of the hydraulic study showed that, Pall rings medium has the highest hydraulic conductivity (Kc) value of about 5.55 m/s, compared to 2.40 and 1.51 m/s for Star shape medium and Gravel medium respectively. Pall rings biofilter achieved the highest percentage of flow passing through the clean media to the total applied flow rates (8.7 - 19.0%), followed by Star shape biofilter (8.6 - 18.0%) of the total applied flow rates, and finally gravel (2.6 - 5.1 %). 11 |