Biological sand filter system treating winery effluent for effective reduction in organic load and pH neutralisation

Abstract

Wineries generate 0.2–14 L of wastewater per litre of wine produced, which is often used for irrigation or discharged into aquatic systems. To mitigate adverse environmental impacts, there is a need for low cost wastewater treatment options. The novel biological sand filtration system described in this pilot study is a sustainable off-grid modular system which can be easily retrofitted to current infrastructure. The system was operated with average hydraulic and organic loading rates of 150 Lm−3 sand.day-1 and 152 gCOD.m−3 of sand.day−1, respectively. Over 762 days of operation, average removal efficiencies of 79% and 77% in terms of chemical oxygen demand and total phenolic concentrations were achieved. In addition, an average 1.8-fold increase in the calcium concentration was achieved, with a concomitant reduction in the sodium adsorption ratio and similar indices. This pilot study also confirmed in a ‘real world’ setting the results of laboratory-based studies where biological sand filters neutralised acidic synthetic winery wastewater and reduced the organic load.