Cost estimation and economical evaluation of three configurations of activated sludge process for a wastewater treatment plant (WWTP) using simulation

Abstract

The activated sludge (AS) process is a type of suspended growth biological wastewater treatment that is used for treating both municipal sewage and a variety of industrial wastewaters. Economical modeling and cost estimation of activated sludge processes are crucial for designing, construction, and forecasting future economical requirements of wastewater treatment plants (WWTPs). In this study, three configurations containing conventional activated sludge (CAS), extended aeration activated sludge (EAAS), and sequencing batch reactor (SBR) processes for a wastewater treatment plant in Tehran city were proposed and the total project construction, operation labor, maintenance, material, chemical, energy and amortization costs of these WWTPs were calculated and compared. Besides, effect of mixed liquor suspended solid (MLSS) amounts on costs of WWTPs was investigated. Results demonstrated that increase of MLSS decreases the total project construction, material and amortization costs of WWTPs containing EAAS and CAS. In addition, increase of this value increases the total operation, maintenance and energy costs, but does not affect chemical cost of WWTPs containing EAAS and CAS.

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

“…The lack of longitudinal mixing can decrease the ability to handle shock loads; there is little dilution of the inflow so toxic material may affect microorganisms. Discouraging the excessive growth of filamentous organisms that can cause settlement problems in the secondary clarifier is the main advantage of the plug flow activated sludge process [3,15,24].…”

“…Application of these systems is discouraged for large flow rates due to the more sophisticated operation needed at larger SBR plants. This technology is specially suggested for low flow rates (e.g., wastewater flow rates of less than 22 L/s (0.5MGD)) [3,4,15,24,35,36]. SBR performance can be affected by organic loading rate, HRT, SRT, dissolved oxygen (DO), and influent characteristics such as COD, solids content, and C/N ratio [3,37,38].…”

“…In this study, CapdetWorks 2.5 with equipment costing database Sept 2007 (USA, Avg) was used for cost estimation to build, operate and maintain the PRWWTPs. CapdetWorks calculates all the costs-total project construction, total operation, maintenance, material, chemical, energy, and amortization for each treatment alternative [24].…”

“…In the petroleum refinery wastewater treatment plant (PRWWTP) design, in addition to improving effluent quality, it is necessary to optimize energy consumption and decrease the use of chemicals in the treatment system [23,24]. Computer simulation is a useful tool in the analysis of the performance, effectiveness, and economics of wastewater treatment plants (WWTPs) [25,26].…”

“…Cost prediction prepares a powerful tool for design, construction, and forecasting future economic requirements [24]. Some researchers have carried out mathematical modeling and simulation of WWTPs [24][25][26][27][28][29][30][31][32][33][34]; but, as far as I know, there is no research on modeling and simulation for the application of SBR technology in the PRWWTP. In this study, the performance and economics of the CAS process replacing by SBR technology in a two train PRWWTP were evaluated using a simulation.…”