Membrane Filtration of Wastewater Effluent for the Reuse Potential in Macau

Proper uses of adequately treated wastewater to supplement fresh water are gaining more public acceptance around the world due to the severity of fresh water shortage and rapid urbanization. Macau is also striving to build a water saving society so as to sustain its rapid development. The aim of this study is to investigate the most regionally feasible tertiary wastewater treatment, to be retrofitted to one of the existing Macau wastewater treatment plants, in order to find a more environmentally sound, sustainable, and economic way to render its treated wastewater attaining recognized qualities for such region-specific reuse purposes as street washing, landscape irrigation, etc. Two methods, sand filtration and microfiltration using membrane filter, both alone or followed by UV disinfection downstream, were identified the most feasible regionally and tested in laboratory-scale using the effluents from regional wastewater treatment 'plants. Results show that sand filtration is not good enough while membrane filtration with UV disinfection delivers promising results, meeting the wastewater effluent standards for reuse purposes currently administered in developed countries. Cost analysis was also performed for the membrane filtration using the experimental data along with the operational manual for the pilot-scale membrane filtration.