Energy recovery and efficiency improvement for an activated sludge, agro-food WWTP upgrade Arianna Callegari a , Joanna Boguniewicz-Zablocka b and Andrea G. Capodaglio a, * a Department of Civil Engineering & Architecture, University of Pavia, Via Ferrata 3, 27100 Pavia, Italy b Opole University of Technology, ul. Mikolajczyka 5, 45-271 Opole, Poland *Corresponding author. E-mail: capo@unipv.it Abstract Wastewater treatment’s primary purpose is to protect surface water quality, aquatic life, beneficial and rec- reational uses of waterways, and primarily comply with local water emission standards. Lately, additional requirements were added for these facilities, concerning minimization of a series of sidestream environmental impacts (i.e., odours, generated waste by-products, etc.), air emissions, including CO 2 , methane and nitrogen greenhouse gases (GHGs), and mitigation of various other likely impacts resulting from energy and chemical use in treatment processes. This paper describes a case study in Northern Europe, where critical analysis of an industrial wastewater treatment plant’s present conditions, during an evaluation of upgrade possibilities to improve regulatory compliance, led to a sustainable intervention proposal. According to the formulated proposal, process improvement, energy recovery, and overall savings and GHG emissions reduction could be simul- taneously achieved with a series of relatively simple interventions. Key words: carbon footprint, energy recovery, GHG emissions, process efficiency, sustainability, upgrade, WWTP INTRODUCTION Wastewater treatment’s primary purpose is to protect surface water quality, aquatic life, beneficial and recreational uses of waterways, and compliance with local water emission standards. Hence, in addition to appropriate monitoring of liquid discharge streams from such facilities (Capodaglio et al. 2016a; Capodaglio 2017a), minimization of the overall environmental impact should be included in their planning, in view of achieving overall sustainability of this type of facility (Capoda- glio et al. 2016b; Capodaglio et al. 2017). Odours and other air emissions (such as CO 2 , methane and nitrogen greenhouse gases (GHGs)) (Capodaglio et al. 2002; Torretta et al. 2016), emerging pollutant- containing flows (Cecconet et al. 2017a; Trojanowski et al. 2017), secondary waste streams, and other impacts resulting from energy and chemical (mis)use in treatment processes should also be taken into account. In comparison to other engineering disciplines, focused mainly on products or production pro- cesses, wastewater treatment, whose primary purpose is the protection of the water environment, has surprisingly made probably less progress in the specific development and application of sustain- able design concepts in its field. Recent advancements in the application of sustainable thinking have explored the possibility of resource recovery from wastewater (Daigger 2009; Verstraete et al. 2009; Capodaglio et al. 2013; Capodaglio et al. 2016c; Cecconet et al. 2017b), and the consideration of broader impacts in process or infrastructure selection (including public acceptance, global warming potential, etc.) (Keller & Hartley 2003; Capodaglio 2017b). © IWA Publishing 2018 Water Practice & Technology Vol 13 No 4 909 doi: 10.2166/wpt.2018.099 Downloaded from http://iwaponline.com/wpt/article-pdf/13/4/909/527459/wpt0130909.pdf by guest on 07 November 2021