Performance Evaluation of a Full-scale SBR and a Conventional Activated Sludge Treating Municipal Wastewater Using GPS-X Software and Providing Options for upgrading

Abstract

Abstract Softwares have been applied for modeling and simulating of wastewater treatment systems. Theses are used for predicting the current situation for finding the most effective treatment plan. GPS-x software is a user-friendly software that use the up-to-date methods in wastewater treatment processes for predicting wastewater treatment system behavior, and simplifying the interpretation of the results by providing graphical reports. In this thesis, GPS-X software (version 8.0.1) was used to evaluate the Maragheh municipal wastewater treatment plant's performance. Data recorded in the wastewater treatment plant laboratory such as influent and effluent wastewater characteristics, physical information of the treatment plant including the number of units, shape, dimensions and volumes as well as the operational information including the concentration of dissolved oxygen, Sludge volume index and flow rates were used for model simulation and calibration. MANTIS2 model was applied to simulate the treatment plant. This is the latest and the most complete model in GPS-X software for modeling of organic matter, nitrogen, and phosphorus all at the same time. We also used Monte Carlo simulations to assess wastewater treatment plant performance. Moreover, the plant performance was predicted by the third phase construction assumption. In the next scenario addition of a sand filter was evaluated. In addition, the scenario of converting the CAS reactor to IFAS and converting the CAS reactor to IFAS plus a sand filter was investigated. The results showed that the effluent of SBR system provides national surface water discharge standards. However, the COD and nitrogen concentrations in the CAS effluent exceeded the permissible limit for discharge to surface water so upgrading this system is necessary. Based on the simulation results, the design of Maragheh wastewater treatment plant has been done correctly, and when the flow rate entering is equal to the design value, the CAS and SBR systems provide national discharge standards to surface water. The simulation results showed that assuming the construction of the third phase, CAS and SBR systems will perform appropriately. By evaluating the various options for upgrading the CAS system with GPS-X software, two of the most effective technical and economical options were selected to improve the performance of the CAS system for providing national standards for wastewater discharge to surface water. The first option includes the conversion of the CAS reactor to IFAS with 25% filling of the reactor with media and dissolved oxygen of 3 mg/liter, which improves the removal of orthophosphate, ammonia nitrogen, and COD of 51.59, 41.13, and 12.01%, respectively. The second option includes the conversion of the CAS reactor to IFAS with 50% filling of the reactor with media and dissolved oxygen of 2 mg/liter, which improves the removal of orthophosphate, ammonia nitrogen, and COD of 25.48, 42.34, and 14.23%, respectively. Keywords: GPS-X software, wastewater treatment plant, simulation, optimization, conventional activated sludge, IFAS, SBR