Buletin Keairan media Informasi Kegiatan Penelitian Keairan, Vol. 2 No. 2, Desember 2009, ABSTRAK : Waterwater treatment plants in industries usually apply a physical and chemical proses that results also slugde, causing a problem if not stored in proper place and polluting the evironment of river, deep and shallow wel etc. The main process of re-using sludge resulting from the wastewater treatment plant as coagulant is to collect sludge from the treatment plant, then fix, break ang sun-dry it. When dry, this sludge can be used as coagulant in the phsical-chemical treatment process. Water analysis results of deep wells in surroundings of study area containing sludge still fulfill the set criteria, except for parameter phenol that shows 0,328 mg/L. Results of laboratory experiment show that sludge from the wastewater treatment plant can be re-used as re-coagulant increasing the efficiency parameters such as BOD : 40-41%; COD : 47-52% and TSS: 38-41%.