Direct sewage up-concentration by submerged aerated and vibrated membranes.

Membrane filtration is a promising technology for realising the so-called ZeroWasteWater concept, i.e. the wastewater can be up-concentrated and the retentate can sequentially be sent to a bioreactor (e.g., for energy production) while the permeate is aimed for reuse. In the present study, aerated and novel vibrated membrane filtration systems were evaluated as possible techniques for both energy and water recovery through the up-concentration of sewage from a municipal wastewater treatment plant. The lab-scale experiments proved the clear advantage of vibrated membrane filtration over the aerated system, considering both the filtration performance (fouling control) and energy usage. Both microfiltration systems were found efficient in up-concentrating the COD, but not the nitrogen nor the phosphorus. The semi-continuous pilot-scale experiment could not confirm the usefulness of the process which was due to both fast in situ microbial COD degradation and fast particulate COD settling in the feed tank.