Arezoo Fereidonian Dashti - PhD student, Universiti Sains Malaysia, School of Civil Engineering, Penang, Malaysia
Mohd Nordin Adlan - Professor, Universiti Sains Malaysia, School of Civil Engineering, Nebong Tebal, Malaysia
Hamidi AbdulAziz - Professor, Universiti Sains Malaysia, School of Civil Engineering, Nebong Tebal, Malaysia
Ali Huddin Ibrahim - Research officer, Universiti Sains Malaysia, School of Civil Engineering, Nebong Tebal, Malaysia

Roughing filter can be considered as a major post-treatment process in waste water management. It reduces influent colour and suspended solids to a level that is effective for operation; meanwhile, roughing filter presents a promoting method for improving raw water quality without using any chemicals. This research aims at improving Palm Oil Mill Effluents (POME) using limestone roughing filter to remove colour and chemical oxygen demand. To obtain this goal, four different series of experiment that involved different sizes of limestone filter media and various filtration rates were carried out, the four categories of limestone filter media included small size (3-6mm), medium size (6-12mm), large size (12-20mm) and a combination of the three filter media and were utilized in the experiment with three different filtration rates of 0.3 m/h, 0.8 m/h and 1.5 m/h. The results indicated that achieving efficient COD and colour removals depend on the size of filter media and the applied flow rate. COD and Colour, removals were found 59.64%, 63.43%, Removal efficiency was found increased with slower flow rate and the smallest size of media.

Roughing Filter, Pretreatment, Palm Oil Mill Effluent (POME), Limestone