Investigation of the potential energy saving in a pilot-scale sequencing batch reactor
Luccarini L., Pulcini D., Sottara D., Spagni A.
Energy is one of the three highest costs for wastewater treatment facilities besides personnel and sludge disposal (Lazarova et al., 2012; Zessner et a., 2010). Most of the middle and large-scale wastewater treatment plants (WWTPs) are designed to leverage some kind of activated sludge process; however, such processes are highly demanding in terms of energy, since more than 50% of the total energy consumed in WWTPs is normally used for aeration and mixing of the activated sludge tank (Lazarova et al., 2012). Since the aeration systems are fundamental to support the biological activity in activated sludge and, at the same time, the most energy demanding process, much research and technological innovation has been funded to improve their efficiency (Amand and Carlsson, 2012; Jeppsson et al., 2013). WWTPs are designed to manage peak flowrates or at least a large fraction of the worst-case scenario flowrates (Tchobanoglous et al., 2003). This leads to the design of oversized tanks if compared to the volumes actually required to treat the average flowrate, so WWTPs usually work at low loading rates. The design of oversized tanks (or 'safety margins') together with large plant dynamics could cause large energy waste if plants are not properly managed (Olsson and Newell, 1999). Nowadays, an efficient management of any WWTP cannot ignore the support offered through automation and information technology, in order to reach the effluent quality standards required by legislation and process sustainability and to limit the energy costs. To this aim, optimizing oxygen addition through the aeration systems by using control logic or automatic policies is fundamental; however, the choice of the most effective control logic or policy strictly depends on the configuration of the evaluated plant. This chapter provides an overview of a pilot-scale study carried out to evaluate the potential energy saving for aeration in wastewater treatment by using sequencing batch reactors.
In: Sewage Treatment Plants: Economic Evaluation of Innovative Technologies for Energy Efficiency - Editor(s): Konstantinos P. Tsagarakis and Katerina Stamatelatou - IWA PUBLISHING Pages: 376. Publication Date: 27 Feb 2015 ISBN: 9781780405018.