Simultaneous hydrogen production and pollutant removal from olive mill wastewaters using electrohydrolysis process

Management of olive mill wastewaters is one of the most challenging environmental issue in Mediterranean countries due to its high organic load, color, presence of phenolic compounds and need for high energy cost. Performance of electrohydrolysis (EH) process in terms of removal of organic compounds, detoxification and discoloration of olive mill wastewater (OMW) with simultaneous energy production in the hydrogen gas form has been investigated using aluminum electrodes. Different reaction times and electric potential gradients have been tested in order to determine the most effective conditions for removal of pollutants. The optimum reaction time and current were determined as 8 h and 8 V, respectively. Under these conditions, removal efficiencies for tCOD, suspended solids, color and phenol were obtained as 73%, 84%, 91% and 75%, respectively. At the end of the operating period of 8 h, 1037 ml hydrogen gas was obtained. The results show that electrohydrolysis process can be used as an alternative solution for the management of OMW and the process can be upgraded with a better reactor design or combined with different treatment processes to achieve a better effluent quality to meet discharge standards. (C) 2019 Elsevier Ltd. All rights reserved.