Sand filtration has been an effective wastewater treatment process for control of contaminates. Sand filters are very economic treatment and do not need constant operator attention, making them an appropriate technology for wastewater systems either they are big or small. Iraq has combined wastewater systems (domestic and storm) water, old treatment plants with very determinate characteristics of influent
(suspended solids S.S equal to 350 mg/L), increasing population and absence of industrial water treatment units; all these conditions lead to problems of overflow, bypass wastewater and effluent which have characteristics under what are required. The results of this paper demonstrate that 76% removal efficiency (R.E) for S.S.
can be achieved by using sand filtration technique. The best position of sand filter is in 2nd stage (pretreatment) because of the
highest R.E of S.S. High possibility to contaminate filter in 1st because of oils and floating materials makes this position not good in spite of high R.E. As a result of this position, effluent will be very low contaminate (s.s reaches 5-10 ppm). In oppose to ordinary effluent which has 69 ppm of s.s ( according to international
environmental standards , effluent's s.s should be 35 ppm or less and according to Iraq E.S effluent's s.s should be 60 ppm or less ) .No desirable change in s.s concentration Is noticed with different sand thickness. Sand filtration appears unexpectable ability (approximately 50%) to remove iron and toxic cadmium.