Thermochemolysis of winery wastewater particulates—Molecular structural implications for water reuse

Environmental concerns have increased the interest in winery wastewater remediation and reuse. These practices require more detailed understanding of wastewater composition to ensure optimum usage, and to minimize the risk of long term soil degradation and grape contamination. Particulate organic matter is an important contributor to the carbon burden in winery wastewaters. This article investigates the molecular structure of particulates from the most common winery wastewater treatment processes via infrared spectroscopic and thermochemolysis-gas chromatography/mass spectrometry techniques. Study of the organic composition of both influent and effluent particles enabled further insight into which compounds could prove problematic during treatment and on discharge. The yield and molecular structure of desorbed or “guest” compounds were found to strongly correlate with those produced during pyrolytic cracking. These “guest” compounds and macromolecular fragments form a continuum whose separation is based on molecular size. Polyphenolic and lignin derived compounds tended to survive the water treatment processes within assemblages of microbial detritus. No evidence was found for particles adsorbing and concentrating other unrelated organics such as anthropogenic chemicals from winery wastewaters. Any release of particulates will require careful management to prevent localized accumulation of recalcitrant compounds to toxic levels.