Temperature phased anaerobic digestion with side-stream archaea enrichment for Lulu Island wastewater treatment plant digester upgrade

废水处理厂(WWTP)的污泥处理是主要挑战之一，其成本往往高于液体的处理和排放。在几种污泥处理方案中，厌氧消化(AD)被证明是一种有效的技术。AD本质上是一个生物反应器，通过引入有机物，如污水污泥或粪便，诱导微生物形成挥发性脂肪酸和甲烷。除了产生甲烷(可转化为热/电)外，AD的其他好处还包括从垃圾填埋场转移有机废物、减少固体、病原体、生产有机肥料以及减少温室气体排放。不列颠哥伦比亚省里士满的露露岛污水处理厂一直在平行运行两个单级AD。虽然该工艺实现了63%的固体减少，但当其中一个消化池需要关闭进行维护/维修时，当前的配置不能提供工艺冗余。此外，脱水后的沼泽地符合B类生物固体的条件，但土地应用受到限制。为了降低运营风险和加强资源回收，温哥华麦德龙有兴趣在其污水处理厂开发下一代AD技术。在这个项目中，一个带有侧流生物增强器的双级AD串联被建议作为一个高级AD选项，用于增加固体减少、将沼气甲烷组成从典型的60%提高到90%或更高、增强沼气脱水能力、以及将生物固体从B类升级到A级。该项目还将包括微生物图谱与精选多组体(DNA和RNA)分析相结合，以深入了解传统和高级AD配置中的群落结构、活性和功能。温哥华大都会的预算为100万美元，用于在卢卢岛水资源回收设施整合和运行一个试点规模的AD，并为升级工厂提供沼气进入电网提供1300万美元。从这个项目中获得的实验室规模的结果将为试点工厂的设计/建造/运行提供明确的方向，这将使先进的AD过程能够在不危及持续运营的情况下进行脱机评估。

Waste sludge processing at wastewater treatment plants (WWTPs) represents one of the major challenges, often costing more than the treatment and discharge of the liquid stream. Among several waste sludge treatment options, anaerobic digestion (AD) has proven to be an effective technology. AD is essentially a bioreactor that induces microorganisms to form volatile fatty acids and methane, supplied through the introduction of organic matter such as sewage sludge or manure. In addition to generating methane (which can be converted to heat/electricity), the other benefits of AD are the diversion of organic waste from landfills, reduction of solids, pathogens, production of organic fertilizer as well as reduction of GHG emissions. Lulu Island WWTP (Richmond, BC) has been operating two single-stage AD in parallel. Although the process achieves 63% solids reduction, the current configuration does not provide process redundancy when one of the digesters needs to be shut down for maintenance/repair. Moreover, the dewatered digestate qualifies as Class B biosolids with restrictions for land application. For reducing operational risks and intensifying resource recovery, Metro Vancouver is interested in developing next generation AD technologies at their WWTPs. In this project, a dual-stage AD tandem with a side-stream bioaugmentor is proposed as an advanced AD option for increasing solids reduction, upgrading biogas methane composition from the typical 60% to 90% or higher, enhancing digestate dewaterability, and upgrading biosolids from Class B to Class A. The project will also include microbial profiling combined with select multi-omic (DNA and RNA) analyses to gain insight to community structure, activity and function in both conventional and advanced AD configurations. Metro Vancouver has budgeted $1M to integrate and operationalize a pilot-scale AD at Lulu Island Water Resource Recovery Facility and $13M for a plant upgrade to feed biogas into the power grid. Lab-scale results obtained from this project will provide clear direction for the pilot-plant design/built/operation, which will enable the evaluation of advanced AD processes "offline" without risking ongoing operations.