| dc.description.abstract | Surface water before being used for particular purposes must be processed first in order to be viable consumed. One of the worth attempts is by building a water treatment such as the installation of Water Treatment Plant that been practiced by PT. Krakatau Tirta Industri, Cilegon. One of the processes is coagulation using aluminium sulfate powder and liquid as the coagulant. This research purpose is to find the optimum dose of aluminium sulfate (liquid) at PT. KTI by comparing the quality and the production cost. The methods including several stages such as preparation phase, data collection, data processing and analysis and presentation of results. The optimum dose for powder using is 60 ppm and for liquid is 100 ppm. The production cost of aluminium sulfate (liquid) using wet alumina is Rp 6.491.838,36 and the cost of goods is Rp 1.131,17/ kg and for dry alumina the production cost is Rp 8.829.278,36 and the cost of goods is Rp 1.538,46/ kg the cost are cheaper than the aluminium sulfate powder cost of goods Rp 1.760/ kg. As resulted from the sensitivity test, the most sensitive variable from the cost of goods is sulfate acid for wet alumina and dry alumina for aluminium sulfate that using dry alumina as the raw material. | en |
