Advances in Technology Innovation, vol . 3, no. 2, 2018, pp. 59 - 69 Improving Activated Sludge Wastewater Treatment Process Efficiency Using Predictive Control Ioana Nascu 1 , Ioan Nascu 2,* 1 Artie McFerrin Department of Chemical Engineering, Texas A&M, College Station TX, USA. 2 Department of Automation, Technical University of Cluj-Napoca, Romania. Received 05, June 2017; received in revised form 07, June 2017; accepted 09, July 2017 Abstract This paper investigates the performance of a new predictive control approach used to improve the energy efficiency and effluent quality of a conventional Wastewater Treatment Plant (WWTP). A modified variant of the well-known Generalized Predictive Control (GPC) method has been applied to control the dissolved oxygen concentration in the aerobic bioreactor of a WWTP. The quadratic cost function was modified to a positional implementation that considers control signal weighting and not its increments, in order to minimize the control energy. The Activated Sludge Process (ASP) optimization using the proposed variant of the GPC algorithm provides an improved aeration system efficiency to reduce energy costs. The control strategy is investigated and evaluated by performing simulations and analyzing the results. Both the set point tracking and the regulatory performances have been tested. Moreover, the effects of some tuning parameters are also investigated. The results show that this control strategy can be efficiently used for dissolved oxygen control in WWTP. Keywords: predictive control, process optimization, process model, wastewater treatment plant, activated sludge treatment 1. Introduction Wastewater treatment plants are key infrastructures for ensuring a proper protection of our environment. Biological treatment is an important and integral part of any WWTP. The Activated Sludge Process is the most commonly used technology to treat sewage and industrial wastewaters due to its flexibility, high reliability and cost-effectiveness, as well as its capacity of producing high quality effluent. An overview of the activated sludge wastewater treatment process mathematical modeling is presented in [1] and application of ASP models can be found in [2]. The ASPs are d ifficult to be controlled because of their complex and nonlinear behavior. However, the optimal control of the biological reactors plays an important role in t he operation of a WWTP and the efficiency of most WWTP is an important issue still to be improved. A good control of WWTP processes could lead to better water quality and to an efficient use of energy [3-4]. This research area is a key part of keeping the environment clean and nowadays has received great emphasis due to the strict regulations for the discharged water. Many of the WWTP are operated in a less-than-optimal manner with respect to both treatment and energy efficiency, causing high costs and inefficient operation in order to meet the regulations. * Corresponding author. E-mail address: ioan.nascu@aut.utcluj.ro Tel.: +40-264-40122 brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by Taiwan Association of Engineering and Technology Innovation: E-Journals