Anaerobic Digestion of Waste Activated Sludge at Psychrophilic Temperatures with Ozonation to Reduce Biosolids Production and Enhance Energy Recovery

点击翻译按钮获取中文摘要

The wastewater treatment industry is undergoing a major transformation by increasingly focusing onwastewater resource recovery instead of simply wastewater treatment. Energy is an important resource that canbe recovered from wastewater, and several facilities aim at operating energy neutral processes. At the sametime, biosolids disposal is a major operational expense as it can use up to 60% of a facilities yearly budget. Thecurrent proposal aims at tackling this combined problem by both minimizing biosolids production and bymaximizing biomethane yields. This will be accomplished though treating waste activated sludge (WAS) withozone to enhance it degradability in anaerobic digestion, and though operating the anaerobic digesters atpsychrophilic (20°C and lower) temperatures. The ozone treatment will allow the operation of thepsychrophilic anaerobic digester at high rates, which corresponds to solids retention time (SRT) equal or lowerthan 20 days. Thus, beside the decrease in operation temperate, the operation of the digesters will not bemodified substantially from the typical conditions. The enhanced degradability of the WAS will alsopotentially create additional process capacity, which may reduce capital investments for the water resourcerecovery facilities (WRRF). This new process will be the first of its kind by which the hydrolysis action ofozone will be used to reduce the digester operation temperature and directly increase the biogas output whilemaintaining a relatively low SRT. The current NSERC-CRD proposal is joint with an NSERC-ARD proposalpresented by the Centre National en Électrochimie et en Technologies Environnementales (CNETE; affiliatedwith the Collège Shawinigan). The new process developed through the proposed project, which will becommercialized by Air Liquide and its partners, will likely provide important economic and environmentalbenefits to the Canadian wastewater resource recovery industry. It will also generate employment within AirLiquide and its partners for commercializing, manufacturing, and installing the new processes.