Color and Organic Removal of Resin Regeneration Wastewater from White Sugar Production Process Using Zero Valent Iron and Persulfate

Abstract

Resin regeneration spent wastewater (RRW) from white sugar production contain salt which can be recovered and reused. However, the wastewater also has high organic and color from melanoidin which leads to membrane fouling during brine recovery. This research investigated the removal of organic and color of RRW using persulfate based advanced oxidation process with zerovalent iron powder (ZVIP) to generate SO₄^•- for oxidizing organics. The effect of temperature on the reaction of persulfate (PS) as well as ratio of ZVIP/PS were examined. The results at high temperature (70°C) showed superior TOC removal. At the best condition (PS 5 mg/L), TOC and color removal were 46% and 94%, respectively. This PS concentration (5 mg/L) was chosen to study the effect of iron concentration. The ratio of ZVIP:PS at 0.01 g/L:5 g/L gave the highest TOC removal of 47%. It was clear that increasing temperature provided better TOC removal. However, adding iron provided a small increase of TOC removal and may dissolve and added more color to the water. Therefore, the result of this work showed that only PS alone may be sufficient for TOC and color removal.