Life Cycle Assessment as an environmental evaluation tool for control strategies in wastewater treatment plants M. Meneses a, * , H. Concepci  on a , D. Vrecko b , R. Vilanova a a Department of Telecommunications and Systems Engineering, Universitat Aut onoma de Barcelona, 08193 Bellaterra, Barcelona, Spain b Department of Systems and Control, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia article info Article history: Received 27 August 2014 Received in revised form 14 May 2015 Accepted 14 May 2015 Available online 2 June 2015 Keywords: Environmental impact assessment Multicriteria decision making Wastewater treatment plant operation BSM2 abstract The objective of this paper is to show the potential additional insight that results from adding indicators based on Life Cycle Assessment (LCA) to the evaluation criteria of plant performance in the control strategies of wastewater treatment plants. Our assessment combines plant-performance evaluation criteria as effluent quality and operational cost defined by the Benchmark Simulation Model, jointly with a detailed environmental evaluation for impact category provided by LCA. Comparison of control stra- tegies shows that the use of ammonia and carbon controllers provides best effluent quality index, whilst the control strategy that uses ammonia, carbon and storage tank controllers has the lowest values as regards operational cost (the storage tank decrease the operational cost index into a 15%). However, environmental analysis indicates that the control strategy using ammonia, carbon and storage tank controllers generates the lowest environmental impacts in all impact categories except eutrophication; whereas the control strategy using only the carbon controller has the lowest impact on eutrophication (6% lower than the higher control strategies), but the largest impact on the remaining categories (from a 9% higher for terrestrial Ecotoxicity to a 97% higher for the Photochemical oxidation). According to the multiple evaluation criteria results, the control strategy using ammonia, carbon and storage tank con- trollers is considered as most suitable to implement, highlighting the importance of environmental analysis as an additional source of information for decision makers. The results reported here underline the importance of taking into account integration of the plant performance criteria with environmental evaluation based on LCA for control strategies in wastewater treatment plants. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction The continuous modification of environmental legislation by most European countries over recent decades led to the imple- mentation of European Council Directive 91/271/ECC. The estab- lishment of new discharge limits for pollutants in order to decrease environmental damage caused by the operation of the wastewater treatment plants (WWTPs) has produced a number of changes in this area. Implementation of distinct control techniques and improvement in existing approaches have upgraded effluent quality; however, on the other hand, additional financial cost has been reported due to the increase in consumption of energy and chemical reagents, as well as greater sludge generation. WWTPs are very complex processes that encompass, biological, transport and hydraulic phenomena, among others. There is also a few considerable ranges of plant layouts. All these factors make it difficult to propose control and operation alternatives and, in particular, complicate their evaluation and comparison. With the aim of solving this problem, a Benchmark was developed by the Working Groups of COST Action 682 and 624 for the evaluation of control strategies in wastewater treatment plants. The Benchmark is a simulation environment defining a plant layout, a simulation model, influent loads, test procedures and evaluation criteria (Alex et al., 1999). Benchmark Simulation Model No. 1 (BSM1) was the first of the Benchmark platforms. The plant layout includes a water line, not taking into account sludge treatment. Its evaluation period of 7 days provides 3 dynamic influent files for testing dry, rainy and stormy weather conditions (Alex et al., 2008). On the other hand, Benchmark Simulation Model No. 2 (BSM2) uses the BSM1 for the biological treatment of wastewater, and adds sludge treatment. Furthermore, the evaluation period is extended to 1 year, and the dynamic influent file takes into account temperature variation due to seasonal changes over the entire year (Nopens et al., 2010; * Corresponding author. Tel.: þ34 935813038; fax: þ34 935814031. E-mail address: montse.meneses@uab.cat (M. Meneses). Contents lists available at ScienceDirect Journal of Cleaner Production journal homepage: www.elsevier.com/locate/jclepro http://dx.doi.org/10.1016/j.jclepro.2015.05.057 0959-6526/© 2015 Elsevier Ltd. All rights reserved. Journal of Cleaner Production 107 (2015) 653e661