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

废水处理厂（WWTPs）的废污泥处理是一项重大挑战，其成本往往高于液流的处理和排放。在众多的污泥处理方法中，厌氧消化（AD）已被证明是一种有效的技术。AD本质上是一种生物反应器，通过引入污水污泥或粪肥等有机物质，诱导微生物形成挥发性脂肪酸和甲烷。除了产生甲烷（可转化为热能/电能）外，AD的其他好处是从垃圾填埋场转移有机废物，减少固体和病原体，生产有机肥料以及减少温室气体排放。露露岛污水处理厂（里士满，不列颠哥伦比亚省）一直在平行运行两个单级AD。尽管该工艺实现了63%的固体减少，但是当其中一个消化器需要关闭以进行维护/修理时，当前配置不提供工艺冗余。此外，脱水后的生物固体状态符合B类生物固体的条件，但对土地应用有限制。为了降低运营风险和加强资源回收，温哥华地铁公司有兴趣在其污水处理厂开发下一代AD技术。在这个项目中，提出了一个双级AD串联侧流生物增强器作为一个先进的AD选项，以增加固体减少，升级沼气甲烷组成从典型的60%到90%或更高，提高厌氧脱水能力，并升级生物固体从B类到A类。该项目还将包括微生物分析与选择多组学（DNA和RNA）分析相结合，以深入了解传统和先进AD配置中的群落结构，活性和功能。大都会温哥华已预算100万美元，用于在露露岛水资源回收设施整合和运营一个试点规模的AD，并预算1300万美元用于工厂升级，将沼气送入电网。从该项目获得的实验室规模的结果将为中试工厂的设计/建造/操作提供明确的方向，这将使先进的AD工艺的评估“离线”，而不会危及正在进行的操作。

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.