Anaerobic Digestion of Cork Boiling Wastewater – Effect of Agitation

The main objective of the work was to perform the energy recovery of cork boiling wastewater (CBW) through anaerobic digestion process. The experiments were performed in reactors of work volume of 6 L and different substrate and co-substrate ratios, with temperature control and mechanical agitation, for obtaining greater biogas and biomethane amounts. The operational temperature was mesophilic (38 °C) with the agitation of 15 rpm being carried out for five minutes three times a day. The reactors were fed with different ratios of Inoculum (IN), CBW and cow manure (CM). Two different mixtures were made, namely IN: CBW and IN:CBW/CM, for ratios of 1:2 and 1:2/1 respectively, with agitation being performed 3 times a day and without any agitation.. For tests IN:CBW no continuous agitation and with agitation there was no significant biogas production. For the IN:CBW/CM mixture with continuous agitation in the ratio 1:2/1, there was no biogas production due to the high conductivity and excess production of volatile fatty acids. For IN mixture: CBW/CM no agitation had an accumulated production of 10 L of biogas in 33 days. With the tests carried out, it can be concluded that the process of anaerobic digestion of CBW can be a viable alternative for energy recovery.