Development of a low-cost wastewater treatment system for small-scale wineries.

A pilot-scale winery wastewater treatment system was developed to treat wastewater produced by a small winery (approximately 1200 metric tons of grapes crushed). The pilot system consisted of a sedimentation/aerobic process combined with a bioremediation wastewater cell planted with Juncus ingens. The main design specifications, detailed descriptions of the plant, and analysis of the influent and effluent characteristics (pH, electrical conductivity, total suspended solids, chemical oxygen demand [COD], etc.) are reported for each segment of the system. Over the study period, the mean winery wastewater flowrate was 3.5 m3/d at organic loads of 5000 to 14 000 mg-COD/L. The study measured average removal rates of 72% for COD and 65% for total organic carbon and dissolved carbon. The application of wastewater to the soil increased the soil salinity in the top 30 cm, but remained stable below this. The system also seemed to be effective at neutralizing the pH of the acidic winery wastewater and at removing the phosphorus pool (65%) in the wastewater, whereas the levels of nitrogen and most of the cations increased in the treated effluent. The absorbing/adsorbing and degradation capacity of the soil of the wastewater bioremediation cell did not appear to be exhausted after one vintage. Juncus ingens appeared to grow moderately well, until the end of the vintage, when dieback began to occur. An infilling with organic matter of the surface soil layer under the root zone was observed, which reduced water infiltration and hence system treatment capacity. The data provide evidence that this is a potentially effective wastewater treatment approach for small wineries located in rural areas.