چكيده به لاتين
Alcohol wastewater or vinasse is one of the most polluted effluents due to so many factors, including its acidic pH, high concentration of COD and BOD, high temperature, dark brown color, high turbidity and a high proportion of dissolved organic and mineral substances. In general, three treatment processes, such as Biological process, Physico-Chemical process and Thermal treatment methods, are used to treat the alcohol effluent. In this study, the Evaporation/condensation method followed by Physico-Chemical processes, including electrocoagulation, ozonation and UV irradiation, was examined for the treatment of distillery wastewater. Before using the Physico-Chemical processes, The raw effluent first entered the Evaporation/Condensation procedure to evaporate and condensate 90% of the effluent. After this stage, due to the suitable range of COD achieved from the previous treatment method, the effluent was treated by combining different Physico-Chemical approaches. The effect of various parameters like initial pH, operation time, and air flow rates on COD removal for different treatment methods has been investigated. It was observed that at initial pH of 7, air flow rate of 400 L/h, operation time of 4 h (EC/Ozonation/UV irradiation) and distance between electrodes of 2 cm, about 88% COD removal had been attained. In pure ozonation mode, increasing the air flow rate from 200 L/h to 400 L/h, the percentage of COD removal increased from 6% to 14% and led to a 4.2 times enhancement in mass transfer coefficient. The total energy consumption of different treatment scenarios has been evaluated and it has been illustrated that the energy consumption of the best process (i.e., EC/Ozonation/UV irradiation scenario) was 10.94 kWh/g COD during the first hour of the process. Furthermore, the current density versus time is an S-shape graph which indicates the competition between the production and the consumption of Fe3+ ions. The results showed that the hybrid method was more efficient in COD removal than each process alone. Moreover, in ozonation/electrocoagulation/UV irradiation, the efficiency of COD removal increased from 65% to 88% with the increase of initial pH from 3.42 to 7.
