Biological wastewater treatment in brewhouses

In the article the working principles of wastewater biological treatment for food companies is reviewed, including dairies and breweries, the waters of which are highly concentrated with dissolved organic contaminants and suspended solids. An example of successful implementation is anaerobic-aerobic treatment plants. Implementation of these treatment plants can achieve the required wastewater treatment at the lowest operational expenses and low volumes of secondary waste generated. Waste water from the food companies have high concentration of various organic contaminants (fats, proteins, starch, sugar, etc.). For such wastewater, high rates of suspended solids, grease and other contaminants are characteristic. Wastewater food industry requires effective purification flowsheets using biological treatment facilities. At the moment methods for the anaerobic-aerobic purification are applied. One of such methods is the treatment of wastewater at ASB-reactor (methane reactor) and the further tertiary treatment on the OSB-reactor (aeration). Anaerobic process means water treatment processes in anoxic conditions. The anaerobic treatment of organic contamination is based on the process of methane fermentation - the process of converting substances to biogas. The role of biological effluent treatment is discussed with special attention given to combined anaerobic/aerobic treatment. Combining anaerobic pre-treatment with aerobic post-treatment integrates the advantages of both processes, amongst which there are reduced energy consumption (net energy production), reduced biological sludge production and limited space requirements. This combination allows for significant savings for operational costs as compared to complete aerobic treatment without compromising the required discharge standards. Anaerobic treatment is a proven and energy efficient method to treat industrial wastewater effluents. These days, more and more emphasis is laid on low energy use, a small reactor surface area, low chemical usage and reduced sludge handling costs. When stringent discharge limits have to be met, in many cases anaerobic treatment is followed by aerobic post treatment. During aerobic polishing, final traces of organic pollution (COD/BOD) and nutrients such as nitrogen and phosphorous can effectively be removed. Besides the decrease in the biosolids quantity, the quality of the aerobic sludge is often improved. With anaerobic pre-treatment biodegradable carbohydrates are less easily present in the aerobic reactor inlet. As a result, the number of filamentous bacteria causing bulking sludge in activated sludge plants, is significantly reduced. This results in an improved settleability of the aerobic sludge and consequently a more stable and secure operation of the activated sludge plant. Finally, due to the higher mineralization grade dewaterability of aerobic sludge from activated sludge plants after anaerobic pre-treatment it is often better than without anaerobic pre-treatment