| dc.description.abstract | Population increase densely spesially for Jogjakarta society in factly make surface water of mataram river in filthy that caused by rain water that get into the raw water like a river. Until caused surface water to colour turbid and the containing solid mater load because there its as open channel. Pretreatment of surface water is therefore necessary to removal turbidity and total suspended solid before water go to the last treatment. One of the simple alternative pretreatment in numerous developing countries was passed the soil water through the filter. It's the contain material gravel size usually 24-2mm. Prefilter is not only a simple, efficient, and chemical-free alternative. Beside, do not need mechanicals equipment. This experiment used Up flow (in layers) roughing filter reactor with height variation of medium size gravel and velocity. The first variation to use gravel with size (19; 15.8; ll.l)mm, and second variation to use gravel with size (11.1; 6.3; 2.3)mm, both to operated with velocity variation 0.3 m/hour, 0.6 m/hour, 0.9 m/hour. With wide of the surface reactor was A = 0.3 m² . Total height of sand layer medium h =1.20 m. for the analyze of laboratory, nephelometric methode was used to measure turbidity using a spectofotometer wavelength 390 nm. While analyze of laboratory for TSS use gravemetri methode. Based on the result of laboratory analyze, the removal efficiency of turbidity 37.17-68.51% and TSS 72.66-93.79% this matter happened because there a view of filtration mechanism, that is: filtration process, sedimentation process, interception process and adhesion process. Analisys statistic can be describe that gravel variation and velocity take influenced removal turbidity and TSS. The best of gravel are (19; 15.8; ll.l)mm where the ability of the gravel to filtering is causing by in phase interception process from interpose of filter media. The velocity which is take effect in this treatment is 0.9 m/hour, this is happened because clogging often happened at velocity 0.3 m/hour and 0.6 m/hour. | en_US |
