Treatment of beverage production wastewater by membrane bioreactor

The paper reports on the results of treatment of wastewater from the bottling of water and soft drinks with a membrane bioreactor (MBR) pilot plant. The existing conventional activated sludge process could not produce effluent suitable for discharge due to significant fluctuations of wastewater composition and flow rate. MBR successfully removed pollutants measured as COD, BOD and TOC from the wastewater with an efficiency of over 90%. The main factors negatively influencing the MBR treatment were low biomass concentration and low HRT, which were significant in the case of highly polluted wastewater. Membrane fouling was more pronounced during the first 10 days of the filtration and then gradually slowed down. The most significant fouling was caused by scale precipitation, which was responsible for 70–80% of the loss of membrane permeability. After 60 days of continuous filtration, it was possible to restore the original permeability of the membrane through intensive chemical cleaning with hypochlorite, acid and alkaline solutions.