7.1.5. Refinery Wastewater

Lijiao Ren was the first person to make use of refinery wastewaters [100]. The treatment of six different refinery wastewater samples was observed in mini-MECs. These waste matter samples were assessed separately and in combination with domestic waste matter as MFC feedstock to determine whether the treatability of the waste matter might be enhanced by introducing microbes and nutrients. In MEC testing, the various refinery wastewater collections differed in terms of current production and treatability. All the de-oiled wastewater samples from mixed sources performed well, with one sample providing values similar to DW. Other samples had low current densities as a result of high starting pH or a low BOD. The effectiveness of MECs was investigated using current generation throughout a number of batch-fed cycles. Refinery wastewater (RW) was treated in MECs that were previously acclimated utilizing domestic wastewater (DW) or a 50:50 mixture of RW and DW. The most effective results were obtained from de-oiled refinery wastewater collected from a single site (DOW1), which had a maximum current density of 2.1 ± 0.2 A·m<sup>−</sup><sup>2</sup> (maximum current density), 79% COD removal, and 82% BOD removal. The results observed were consistent with the results obtained from the domestic wastewater treatment study [100].
