Date of Award
Summer 2017
Document Type
Thesis - Restricted
Degree Name
Master of Science (MS)
Department
Civil, Construction, and Environmental Engineering
First Advisor
Zitomer, Daniel H.
Second Advisor
Mayer, Brooke K.
Third Advisor
McNamara, Patrick J.
Abstract
Various types of pretreatment technologies have been studied in an effort to enhance the efficiency of anaerobic digestion of biosolids. These technologies include mechanical, ultrasonic treatment, thermal treatment and chemical treatment. The main goal of these technologies is to achieve cell lysis to increase the digestibility of biosolids. The benefits of enhancing anaerobic digestion include increased biogas production and volatile solids reduction (VSR). If successful, these benefits provide significant cost and energy savings for those that use it. A new technology known as OpenCEL uses electroporation in hopes of enhancing anaerobic digestion by improving biogas production and solids destruction. However, research over various sources of biosolids and reactor configurations is lacking and further research is needed to determine the full effects of OpenCEL. Therefore, the aim of this study was to further investigate the effect electroporation of biosolids has on methane production and solids reduction during anaerobic digestion using combinations primary sludge and waste activated sludge treated by OpenCEL. Four bench-scale anaerobic reactors were operated in this study at the Marquette University Water Quality Center. Waste activated sludge treated by an existing electroporation treatment technology was collected from a local wastewater treatment plant and used as substrate for the bench scale anaerobic reactors. Additionally, laboratory analyses on biosolid characteristics and reactor performance were conducted using the resources available at the Marquette University Water Quality Center. Reactors were operated at Solids Retention Times (SRTs) of 30 days, 15 days and 8 days, respectively. Reactors received one of two different feed mixtures. Mixture A consisted of 65% primary sludge and 35% thickened waste activated sludge (TWAS) by weight. Mixture B consisted of 65% primary sludge and 35% TWAS treated by OpenCEL by weight. The results of this study were conducted while the reactors were at a quasi steady state condition. The reactors receiving mixture A had VSRs of 54%, 50% and 45% for SRTs of 30, 15 and 8 days respectively. The reactors receiving mixture B had VSRs of 56%, 50% and 46% at the same SRTs . Additionally, no increase in methane production was discovered under the operating conditions studied.