Removal of Color from Molasses Wastewater Using Membrane Bioreactor with Acidic Condition

Abstract

The advantage of acidic operation below pH of 3 in membrane bioreactors (MBRs) for the treatment of molasses wastewater was examined. Stable operation of both an acidic reactor and a neutral pH reactor was observed for 91 days. Percent COD removal was 48.5% for the acidic reactor and 63.6% for the neutral pH reactor when biologically pretreated molasses wastewater was fed to the reactors. Higher percentage removals of COD (89.0% for the neutral pH reactor and 84.0% for the acidic reactor) were observed, when molasses wastewater (COD 650 mg/L) was directly fed to the reactor because of higher concentration of biologically degradable organic matter in the feed solution. In spite of lower percentage of COD removal in the acidic reactor, higher percentage of color removal was observed spectrophotometrically with the low pH operation. Higher percentage of color removal in the acidic reactor was probably due to the enhanced adsorption of colored substances in the acidic environment followed by gradual biological degradation.

Advanced Oxidation Processes and Nanofiltration to Reduce the Color and Chemical Oxygen Demand of Waste Soy Sauce

“…Abid, M. F. et al (2012) achieved 93.77%, 95.67%, and 97% removal of red, black and blue dyes using a NF membrane under a pressure of 8 bar [12]. However, it is difficult to remove the color and organic matter completely using typical membrane processes other than reverse osmosis because chromophoric dissolved organic matter generally has various molecular weights [13][14][15]. Furthermore, despite research progress to date, membrane filtration has yet to be applied in removing the intense color to reduce the high COD of waste soy sauce.…”