Direct Filtration for Drinking Water at Habbaniyah Lake (Iraq)
This research aims at elimination of the sedimentation stage from water purification systems, here waters supplied from lakes. chemical are used to coagulate any remaining suspended materials before the filtration stage, chemical used include alum with some catalyst, such as poly electrolytes. An integrated 5,50 m high Direct filtration unit was constructed in the laboratory, it included four main units: an axial flocculating unit, a filtration unit , injection unit for pumping coagulants and clay materials, and a backwashing unit, a piezometric board is also included tot give reading at each 10cm of filter height . Water is supplied to the system through a constant head tank by gravity action. filtration is done through two mediums ,a crushed brick layer2 to 5mm sizes(30to40)cm deep and a quartz sand layer 0-.60to 0.75mm (30to40)cm deep. The partial part was done in two stages:- The first stage included the laboratory procedure, using the constructed filtration system, Baghdad water supply was used, with the addition of kaolin (fine mud used as turbidity)to increase turbidity to find the best combination of variables, loading ,to highest water yield together with highest efficiency, experiments were run to find the effect of filtration rate, type &and depth of filtration materials, effect of coagulating material and added catalyst in addition to the control of flocculation time and velocity gradient. The second stage included the study of the effects of magnitude of turbidity and type of coagulating materials on water yield & on efficiency of filtration system, experiments of this stage were run in habbaniyah, using lake water and water treatment plant of touristic village, by eliminating the sedimentation stage of the plant, the pressurized filtration unit was used, 0.2to0.5mm charcoal, 0.2to 0.5mm sand.
