The aim of this study was to evaluate the feasibility of slow sand filtration as a technique for tertiary treatment of effluent from an anaerobic denitrifying reactor (ADR) treating domestic wastewater. The performance of different Moroccan sand media in tertiary filtration of wastewater has been assessed by conducting pilot-scale filtration assays. The treatment efficiency of a slow sand filtration method depends on several parameters, namely the sand media used, the wastewater characteristics and the organic loading rate. The experimental pilot system consisted of three columns, each one containing a different type of Moroccan sand, namely desert sand (DS), river sand (RS) and beach sand (BS). We found that the optimum hydraulic loading rate at which the effluent is in compliance to water reuse standards equals to 0.16 m/h for all sand filters. Additionally, the RS filter showed the highest pollutant removal efficiency at 0.16 m/h, namely 88% of COD, 86% of TSS, 72% of TKN, 76% of NH₄-N, 65% of TP, 2.4 log-units of FC and 2.7 log-units of FS. The effectiveness of the RS filter is found to be attributed to the highest Al₂O₃, Fe₂O₃ and OM content as well as to the smaller particle size of the sand incomparison to DS and BS filters.