Life cycle assessment of wastewater reclamation in a petroleum refinery in Turkey

摘要

Wastewater reclamation in a petroleum refinery in Turkey was evaluated with life cycle assessment (LCA). The goal of the study was to determine whether or not refinery wastewater reclamation for different industrial purposes, namely boiler feedwater, cooling water and fire water, leads to an overall benefit across different environmental aspects, besides alleviating freshwater resources, when compared to current wastewater disposal practices. The basis for the assessment was the hypothetical scale-up of a demonstration plant tested with real wastewaters from November 2018 to May 2019 at the Izmit petroleum refinery operated by Tupras. This demonstration plant consisted of different treatment modules, including dissolved air flotation, ceramic membrane bioreactor, catalytic wet-air oxidation, advanced oxidation with ozone and hydrogen peroxide, and reverse osmosis. The LCA was conducted following consequential modelling principles, and six environmental indicators were analysed in detail at midpoint level: global warming, respiratory inorganics, marine ecotoxicity, aquatic eutrophication, freshwater consumption and non-renewable energy demand. All three reclamation scenarios (boiler, cooling, fire water) succeeded in achieving a life-cycle freshwater saving, of around 1 m(3) freshwater saved per m(3) refinery wastewater. Beneficial results were also obtained in marine ecotoxicity and aquatic eutrophication, where impact is reduced up to 90% and 84%, respectively. With regard to global warming and non-renewable energy demand, only the boiler feedwater application appeared to involve an improvement over wastewater disposal, showing a net reduction of 2.2 kg CO2-eq and 40 MJ per m(3) wastewater, respectively, thanks to potential thermal energy savings. For cooling makeup water and fire water, impacts were between 2 and 2.5 times higher in these two indicators when compared to wastewater disposal. Finally, the indicator on respiratory inorganic effects, showed higher impact, by a factor 2 to 7, for all reuse scenarios, due to electricity demand, which is linked to the Turkish electricity production mix with a substantial contribution from coal power plants. Thus, the results reflect that achieving a product water of very high quality comes at the price of a high energy demand. Nevertheless, A sensitivity analysis shows that the environmental performance of all scenarios would improve to a great extent when shifting to an electricity mix with a higher share of renewables, as is the current trend in most European countries. (c) 2020 Elsevier Ltd. All rights reserved.