Economic evaluation of the reuse of brewery wastewater

Freshwater scarcity is a global concern, not just in countries with limited water resources, and wastewater reuse is becoming an essential necessity. Beer is the fifth-most widely consumed beverage in the world and breweries are a major industrial water consumer. Within this study, the long-term performance of a modular pilot scale plant reusing brewery wastewater was investigated. The system consisted of a flotation device, a membrane bioreactor (MBR), an ultrafiltration (UF) and a reverse osmosis (RO) system. The system was fed with wastewater from the effluent of a full-scale anaerobic reactor. The combination of flotation device and MBR removed chemical oxygen demand (COD) by 93.6%. The subsequent UF and RO removed remaining organic load and inorganic components and process water was produced, whereby drinking water quality was achieved. A yield of 63% was reached with the pilot plant. Based on the results, a base case cost estimate was carried out for a full-scale application, taking into account the actual hydraulic load of the brewery. In order to predict the uncertainties of cost-sensitive factors, the specific costs for sludge disposal, electrical energy, freshwater supply and wastewater disposal as well as membrane lifespan and yield of the RO unit were expressed by probability distributions. Using the Monte Carlo method with 75,000 iterations, the probability distributions for the costs and economic viability of reusing brewery wastewater were calculated. The estimate found that reusing brewery wastewater can be economically viable in 77.2% of simulated cases showing the strongest dependency on costs for wastewater disposal.