Analysis of the Prasedimentation Buildings Performance on BOD and COD Levels at Siwalan Panji Sidoarjo Water Treatment Plant

Afoer River in Buduran Sub-District of Sidoarjo City is one of the rivers as a source of raw water by Siwalan Panji Water Treatment Plant, this study aims to analyze the capabilities of alternative biofilters in the decline of BOD, and COD in prasedimentation buildings, analyzing the most economical and effective costs of the biofilters used. This research method is an experimental study of planned biofiltration alternatives such as River Rock, Crossflow, Bio-Ball with data testing using the Anova Two Way test. Observation data shows raw water does not meet class I standard of raw water quality, as a solution in improving the performance of Prasedimentation buildings, used River Rock, Crossflow, and Bio-Ball Biofilters. Statistic test results showed decreased organic substance efficiency in River Rock BOD biofilters 87.05%, COD 84.61%, Crossflow BOD biofilters 97.73%, COD 95.35%, and Bio-Ball BOD biofilters 97.64%, and COD 95.26%. The most economical and effective cost analysis result is crossflow biofilter with BOQ value of Rp 383,240,648,- and OP cost per month Rp. 16,545,490,-