Shipboard Wastewater Treatment Using Granular Activated Carbon: Adsorption Test and Bioregeneration

In this study, the adsorption of granular activated carbon (GAC) was evaluated in the treatment of slop with the aim of reducing the organic matter concentration in terms of chemical oxygen demand (COD), dissolved organic carbon (DOC), and total petroleum hydrocarbons (TPH). The process was optimized for the oily wastewaters sampled from a floating tank of an oil coastal deposit in the Augusta Harbor (Sicily, Italy). In particular, both batch and dynamic tests were performed. Two different GACs were used and compared. In general, the application of the adsorption process was effective in the treatment of the slop. In fact, the percentages of removal, although rarely exceeding 65% in term of COD, reduced the overall organic load resulting from recalcitrant or poorly biodegradable substances (efficiency greater than 70-80% in terms of DOC and TPH). However, a pretreatment with 20 gGAC/L is also sustainable for the removal of the main contaminants and for the pretreatment of the wastewater, improving the treatment before a subsequent biological process.