Characterization of chromophoric organic matter in effluent from Vitamin C wastewater anaerobic-aerobic treatment

Chroma is not effectively removed from Vitamin C (VC) wastewater by traditional anaerobic-aerobic treatment. This means current treatment does not meet the strict new discharge standard for VC wastewater in China. However, to date, no studies have investigated the removal of chroma from VC wastewater, or characterized the chromophoric organic matter in wastewater. In this study, choromophoric organic matter in effluent from anaerobic-aerobic treatment of Vitamin C wastewater was characterized using high performance gel permeation chromatography (HPGPC), ultrafiltration, and infrared (IR) and ultraviolet-visible (UV/Vis) spectroscopy. Routine water-quality indices were determined, and indicated that the organic matter in the effluent contained nitrogen. The molecular weight of most organic matter in this effluent was below 1000 Da, while the remainder was between 1000-3000 Da. These compounds are likely biodegradation products of high molecular weight organic matter in the effluent, which are raw materials and byproducts from VC production. IR spectra indicated that the low molecular weight (< 1000 Da) organic matter and higher molecular weight (1000-3000 Da) organic matter contain similar major functional groups, including -OH, -NH2, -CO-NH2, -C=O-, and -COO-. The effluent was treated using electrolysis, and UV/Vis spectra of this effluent before and after electrolysis indicated that -C=O is an important chroma group in this effluent. Electrolysis can easily break -C=O, and provides a feasible technology for the advanced treatment of anaerobic-aerobic effluent from VC wastewater treatment.