Control Of WWTP Integrating Model Predictive Control With Fuzzy Theory

Due to the rising standard of living and human population growth. The demand of energy and clean water source source is increasing significantly. To meet such requirement of clean water, wastewater treatment plant are constructed significantly which is to recycle and treat the wastewater. However, a huge energy is consumed in order to make sure a wastewater plant run under best performance. The United states of America annually spends 56 billion k WH electricity for wastewater treatment plant operation. The effect of large energy usage leads to massive release the greenhouse gas emissions into the air, with 45 million ton of carbon dioxide. The unstable effluent discharge which is produced by wastewater treatment plant also jeopardize for the environment especially for aquatic ecosystem. For example, the nitrogen effluent is one of the causes of eutrophication. The massive nitrogen level in the water leads to decreasing the dissolved oxygen level in the aquatic ecosystem and threaten the lives of aquatic creatures. Therefore, it is necessary to stabilizes the effluent of the WWTP with less energy consumption. This could potentially be achieved by controlling the nitrate and dissolved oxygen concentration in specified level.This research proposes the control strategy involving the combination of PID control, MPC(model predictive control) and fuzzy control. The purpose of the fuzzy-PID controller involved is to control the nitrate level in second anoxic compartment. The combination of PID, MPC and fuzzy is to maintain dissolved oxygen in the third aeration tank. The comparison with default control strategy that provides by Benchmark Simulation Model no.1 has been performed as a compared study. The 14 days simulation has been performed. By implementing the proposed control strategy, the nitrogen and ammonium effluent was reduced by 1.76 % and 1.25%. The proposed control strategy also able reduce the total energy usage by 2027 k WH(1.63%) and 1574 k WH(1.2%) for dealing with carbon addition. For dealing with carbon addition, the proposed control strategy requires less volume of carbon than default control strategy. It saves 0.9(9.78%) of carbon addition volume. The proposed control strategy has succeed to increase the effluent level with lower energy consumption.