Symbiotic Hollow Fiber Membrane Photobioreactor for Microalgal Growth and Activated Sludge Waste Water Treatment

Abstract

This study aimed to develop hollow fiber membrane photobioreactors (HFMPs) for symbiotic activated sludge (AS) wastewater treatment and microalgal biomass production to overcome the limitations in current co-culture photosynthetic oxygenation. In the first part, a HFMP was developed to physically separate microalgal and bacterial cultures, and facilitate the intertransfer of CO2 and O2. Results showed a symbiotic relationship exists between microalgae and bacteria, reflecting by the photo-autotrophic growth of C.vulgaris using the CO2 supply from P.putida and the complete glucose biodegradation in synthetic wastewater by P.putida using O2 produced by C.vulgaris. In the next parts, a submerged HFMP (SHFMP) was developed to retrofit existing AS tank to solve the available space problem in current wastewater treatment plants. With the support from photosynthetic oxygenation, the SHFMP successfully removed 98% COD, 63% NH_4^+-N and 60% PO_4^(3-)-P at the hydraulic retention time of 10 hours. Importantly, clean microalgal biomass was also generated.