Abstarct: Stabilization ponds are one of the simplest and low-cost wastewater treatment technologies. They are common in many countries around the world and produce effluents with desirable quality. However, the concentration of algae in the wastewater stabilization ponds (WSP) effluents are high which can limit their applications when a high-quality effluent is required. Rock filters are one of the methods for algae removal from WSP effluents. Low operation and maintenance (O&M) costs made rock filters a suitable polishing system, particularly for small communities and developing countries. Though, there has been limited research about design and media selection for these polishing units, which is an important subject considering the needs of sufficient quality and low O&M costs in the target communities. In the following thesis, a comparison has been made between the removal efficiency of suspended solids (SS) using angular rock and gravel filters. Besides, turbidity have been measured and compared to SS removal. The results show that with the hydraulic loading rates that had been applied, there is not a significant difference between SS removal from angular rock and gravel effluents, hence, gavel is preferred because it is cheaper. Moreover, biofilm development on rock surfaces changes the amount of effluent turbidity. Thus, turbidity is not a good measure of SS removal efficiency where rock filtering system is applied.