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，越来越多地关注废水资源回收而不是简单的废水处理。能源是一种重要的资源，可以从废水中回收，有几个设施的目标是运行能源中性过程。同时，生物固体处置是一项主要的运营费用，因为它可以使用高达60%的设施年度预算。目前的建议旨在通过最大限度地减少生物固体产量和最大限度地提高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物活性污泥（WAS）来提高其在厌氧消化中的降解性，以及通过在嗜冷（20°C或更低）温度下操作厌氧消化器来实现。臭氧处理将允许嗜冷厌氧消化器以高速率运行，这对应于等于或低于20天的固体保留时间（SRT）。因此，除了操作温度的降低之外，蒸煮器的操作将不会从典型条件显著地改变。提高WAS的降解性也将潜在地产生额外的处理能力，这可能会减少水资源回收设施（WRRF）的资本投资。该工艺首次利用臭氧的水解作用降低沼气池的运行温度，直接提高沼气产量，同时保持较低的泥龄。目前的NSERC-CRD提案与国家电化学和环境技术中心（CNETE;附属于沙维尼甘学院）提出的NSERC-ARD提案联合。通过拟议项目开发的新工艺将由液化空气集团及其合作伙伴重新商业化，可能会为加拿大废水资源回收行业提供重要的经济和环境效益。它还将在液化空气集团及其合作伙伴中创造就业机会，用于商业化，制造和安装新工艺。

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.