The inadequate handling of winery wastewater (WW) has left a harmful impression on the sustainable production of wine 1. Usually, for each litre of wine produced, between 0.2 – 4L of wastewater can be generated, being rich in biodegradable organic matter with typical chemical oxygen demand (COD) concentration varying between 0.3 – 49 g L-1 2–4. Preventing the discharge of WW into surface waters is crucial to mitigate the risks of eutrophication. Biological treatment is widely recognized as a cost-effective approach to treat wastewater 5. However, the selection of a specific biological method for WW treatment depends on various factors, including the size and geographical location of the winery, the volume of wastewater generated, and its organic content 4. In this study, the effectiveness of using a sequencing batch reactor (SBR) as a biological technology for WW treatment was investigated. COD removal efficiencies ranging from 70 to 95% were obtained (without nutrient supplementation), for organic loading rates (OLR) below 3.4 gCOD L-1 d-1 and a hydraulic retention time of 21 h. The best sludge settling properties, (i.e., 78 mL gTSS-1 and 1.1 cm min-1) were observed at an OLR of 6 gCOD L-1 d-1. Despite these good settling properties, only 70% COD removal efficiency was attained, suggesting the need for nutrient supplementation for higher OLR. In fact, the addition of nutrient allowed the improvement of both effluent quality and settling properties for similar OLR. Overall, these findings demonstrate the potential of SBR as a biological WW treatment process.
References
1. Ngwenya, N., Gaszynski, C. & Ikumi, D. A review of winery wastewater treatment: A focus on UASB biotechnology optimisation and recovery strategies. J. Environ. Chem. Eng. 10, 108172 (2022).
2. Amor, C., Marchão, L., Lucas, M. S. & Peres, J. A. Application of advanced oxidation processes for the treatment of recalcitrant agro-industrial wastewater: A review. Water (Switzerland) 11, (2019).
3. Welz, P. J., Holtman, G., Haldenwang, R. & Le Roes-Hill, M. Characterisation of winery wastewater from continuous flow settling basins and waste stabilisation ponds over the course of 1 year: Implications for biological wastewater treatment and land application. Water Sci. Technol. 74, 2036–2050 (2016).
4. Pirra, A. J. D. Caracterização e Tratamento de Efluentes Vinícolas da Região Demarcada do Douro. (PhD Thesis, University of Trás-os-Montes e Alto Douro, 2005).
5. Lemaire, R., Webb, R. I. & Yuan, Z. Micro-scale observations of the structure of aerobic microbial granules used for the treatment of nutrient-rich industrial wastewater. ISME J. 2, 528–541 (2008).
