Low-Cost Mbr For Sewage Treatment As Non-Conventional Water Resource

Document Type : Original Article

Authors

1 Department of Water Pollution Research, National Research Centre, Cairo, Egypt

2 Chemistry Department, Faculty of Science, Ain Shams University, Cairo, Egypt

Abstract

Egypt suffers from water scarcity, therefore non-conventional water resources are needed to secure increasing water demand in the various development processes especially agriculture sector which consumes 85% of the water budget. Well- treated sewage water represents a good source for land irrigation that is an alternate solution for environmental disposal of the treated sewage. In this study, a cloth-media membrane bioreactor (MBR) was designed, manufactured and evaluated for sewage treatment at different operating conditions. Cloth-media filter with 0.553 m2 effective filtration area was submerged in an aeration tank with 50 L theoretical working volume and 44.5 L effective working volume. The system was operated for three different Hydraulic Retention Time (HRT) and two different dissolved oxygen (DO) concentration. The HRTs are 4, 6 and 8 hours while dissolved oxygen concentrations were 4.5 mg/l and 2.3 mg/l. Sludge residence time (SRT) was maintained at 29.7 days by removing 1.5 L from the mixed liquor suspended solids (MLSS) on daily basis. The system operation showed significant impact of the DO concentration and HRT on the treatment performance with higher efficiency at higher DO concentration and longest HRT. At high DO concentration, the range of residual concentrations was 10.4-20.3 mgCOD/L and 4.2-10.1 mgBOD/L while at low DO concentration the ranges were 17.5-30.1 mg COD/L and 7.6-14.8 mg BOD/L. Both DO concentration and HRT have significant impact, directly or indirectly, on the membrane fouling. Economically, the system operation at low DO concentration (2 ppm) and medium HRT (6 hrs) was found cost-effective, sustainable and provided treated effluent complying physico-chemically with reuse standards.

Keywords

Main Subjects