Particulates and bacteria removal by ceramic microfiltration, UV photolysis, and their combination

Abstract

Membrane microfiltration (MF) or ultrafiltration (UF) systems of activated sludge is crucial part of a bioreactor process used in municipal wastewater treatment. In this study, both cylindrical and flat sheet ceramic membranes were used to treat municipal wastewaters. The effects of removing water turbidity and coliform bacteria from an artificial wastewater were studied by performing batch experiments by MF and ultraviolet (UV) photolysis of 254 nm wavelength. It was shown that the microfiltration had a high effect of suspended solid removal. However, the effect of bacteria removal was limited so that the rate of cfu removal was approximately 61%. Combined consecutive processes in the treatment (MF/UV and UV/MF) confirmed that a specific porosity of the ceramic filter for bacteria removal was required. The continuous membrane bioreactor (MBR) tests performed by using a MF membrane with the pore size of 0.2 μ m showed that particulate matter and microorganisms found in municipal wastewater could be effectively removed. Turbidity was decreased from 4.50 to 0.05 NTU, with a removal efficiency of greater than 98%. The permeate total suspended solid (TSS) content for the whole run was below 5 mgL^{− 1}. The density of total coliforms was decreased more than four orders of magnitude (from around 1× 10⁵ mL^{− 1} to less than 5 mL^{− 1} in the effluent).

Keywords:

• Membrane bioreactors
• combined processes
• ceramic filters
• UV photolysis
• municipal wastewater

Notes

*The cfu values for the ceramic filter influent and effluent were 18 cfu/10 mL and 9 cfu/10 mL, respectively.

**The cfu value for the UV reactor influent was 17 cfu/10 mL.