Simulation for the Performance and Economic Evaluation of Conventional Activated Sludge Process Replacing by Sequencing Batch Reactor Technology in a Petroleum Refinery Wastewater Treatment Plant

Treatment of the petroleum refinery wastewater containing complex chemicals using biological processes is usually challenging because of the inhibition and/or toxicity of these matters when they serve as microbial substrates. In addition, performance modeling and cost evaluation of processes are essential for designing, construction, and forecasting future economic requirements of the petroleum refinery wastewater treatment plants (PRWWTPs). In this study, the performance and economics of conventional activated sludge (CAS) process replacing by sequencing batch reactor (SBR) technology in a two train PRWWTP were evaluated using simulation. The final treated effluent characteristics for the PRWWTPs containing CAS + CAS and SBR + CAS processes under steady state conditions were studied and evolution of the main parameters of the final effluent during the 30 days of simulation for these plants were investigated. Finally, the total project construction, operation labor, maintenance, material, chemical, energy, and amortization costs of these plants were estimated and compared. Results demonstrated that the project construction cost of PRWWTP containing CAS + CAS processes was lower than that of PRWWTP containing SBR + CAS processes and the energy and amortization costs for both plants were higher in comparison with the operation, maintenance, material, and chemical costs. Note that this study is a computer simulation and drawing general conclusions only on the basis of computer simulation may be insufficient.