Managing wastewater generated from winery processes poses great deal of problems that need to be addressed, basically related to the high organic load and also mainly due to the reason that loading rate is not always constant throughout the year. The high organic strength of the influent is basically contributed by the presence of soluble alcohol, sugars and organic acids which will cause the BOD/COD levels to go up significantly which also means that it cannot be simply removed by conventional mechanical treatment steps. Apart from that, since production in the wineries only peaked at certain periods of the time throughout the year, trying to manage wastewater treatment using activated sludge biological systems with the control mechanism based on constant loading rate will pose a serious challenge, unless large treatment lagoons are built since they operate on higher detention times and overall provides a good buffer system to prevent pH fluctuation.
Typical composition of the incoming influent usually can be characterized by the presence of high amount of suspended solids and fine particles mainly made up of grape skins, leaves, seeds, stems, dirt and other organic matter generated from the harvesting and crushing processes. These contaminants can be easily removed via coarse screens or through installation of grit chambers before the wastewater is allowed to be fed onto the next treatment steps. Apart from the normal wastewater generated from the winery processing, influent can also come from the routine day-to-day operations taking place in the plant such as during cleaning and emptying of storage tanks, aging barrels, servicing of machinery, laboratory testing generating waste chemicals and also water from general housekeeping such as floor washing. These will result in wastewater containing traces of soap, some residue of oil combined into it and don’t forget all these will also come together with the sanitary wastewater from the factory workers.
It is quite difficult to say how well one can manage and control the overall production processes such as fermentation and distillation because in one way or another, carryover and spillages are normal occurrences that will increase the strength of the wastewater especially when you have unreacted sugar and alcohol mixed into it. And because of these factors, some wineries instead decided to adopt the anaerobic treatment principles and since cost of energy has increased tremendously over the years, biogas which is the by-products generated from the breakdown of organic waste and reuse of these can significantly bring down the overall cost of operation. Furthermore, this system will also not pose much problem because anaerobic reactors are designed to handle high organic strength wastewater and one particular advantage compared to lagoons is that it is also very much space-saving. Other factories in the winery industry rely on sequencing batch reactor (SBR) as an alternative treatment processes but this one is more towards smaller scaled production operations. Whichever methods, if well managed, the treated effluent can be reused back for irrigation purposes serving the needs for water conservation program and with minimal discharge to the environment.
Advancement and improvement in new treatment technologies also provide alternative channels that takes advantage of the benefits of combining different pollutant removal techniques into one single system. One current application is by studying the feasibility of using reserve osmosis principle and whether it is actually possible that this idea be applied in large-scale industrial wine making processes. Another possible solution is by using the artificial wetland approach or either way, a common leach fields can also be created whereby high organic strength wastewater will be directly sprayed on and pass through a series of soil layers that act as natural filter to remove and biodegrade the contaminants.