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

废水处理行业正在经历一场重大变革，越来越注重废水资源的回收，而不是简单的废水处理。能源是一种可以从废水中回收的重要资源，有几个设施旨在运行能源中性过程。同时，生物固体处理是一项主要的运营费用，因为它可以使用设施每年预算的60%。目前的提案旨在通过最小化生物固体产量和最大化生物甲烷产量来解决这一综合问题。这将通过用臭氧处理废弃的活性污泥，以提高其在厌氧消化中的降解性，并通过在嗜冷(20摄氏度或更低)温度下运行厌氧消化器来实现。臭氧处理将允许嗜冷厌氧消化器以高速率运行，这相当于固体停留时间(SRT)等于或小于20天。因此，除了操作温度的降低外，消化器的操作不会实质上受到典型条件的影响。可降解性的增强还将潜在地创造额外的处理能力，这可能会减少对水资源回收设施的资本投资。这一新工艺将是第一个利用氮化物的水解作用来降低沼气池的运行温度并在保持相对较低的SRT的情况下直接增加沼气产量的新工艺。目前的NSERC-CRD提案是与NSERC-ARD提案联合进行的，该提案由国家环境与技术中心(CNETE；附属于大学)提交。通过拟议的项目开发的新工艺将由液化空气及其合作伙伴商业化，可能会为加拿大废水资源回收行业带来重要的经济和环境效益。它还将在液化空气及其合作伙伴内部创造就业机会，将新工艺商业化、制造和安装。

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.