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Abstract In the present study, the use of submerged membrane bioreactor (SMBR) for municipal wastewater reclamation has been investigated. The most common configurations namely; hollow fiber (HF) and flat sheet (FS) were used. To develop optimum operating conditions, two bench-scale modules were used; HF SMBR and FS SMBR. The systems were operated and fed continuously with real wastewater from a near-by municipal wastewater treatment facility. The impact of changing the most influential operational parameters such as hydraulic retention time (HRT), sludge retention time (SRT) and organic loading rate (OLR) on the performance of the two modules was the main focus of the present study. The results obtained indicated that the two modules could ensure a very good quality effluent, regardless of the variations in raw wastewater strength and HRTs. Chemical oxygen demand (COD) and biological oxygen demand (BOD) removal rates above 90% were achieved. Residual suspended solids were below detectable limits. The membranes trapped significant proportions of the pathogenic organisms. At the same time, HRT was found to be a key parameter for fouling. Monitoring the Trans membrane pressure (TMP) indicated that membrane fouling can be reduced by operating the HF SMBR at low permeate flux or longer HRT. Changing the SRT from 30d to 40d and then to 60d did not affect organic compounds removal in terms of COD and BOD removal. Also, complete nitrification has been reported for the three tested SRTs. However, increasing SRT has led to an increase in the rate of membrane fouling. Total fouling resistance (RT) increased from 0.28 x 1013 to 0.4 x 1013 m-1d by increasing SRT from 30 to 60 d. Doubling the applied OLR from 3.48 to 6.6 kg COD/m3d exerted negative impact on the nitrification process. |