Phase B - Evaluation of a combined anaerobic/aerobic/anoxic sludge digestion system for Annacis Island wastewater treatment plant

在加拿大，大中型城市污水处理厂(WWTP)一直在采用厌氧(AN)消化技术，从废水污泥中产生沼气(60-75%甲烷)形式的能量。消化的其他好处包括从垃圾填埋场转移有机废物，减少病原体和气味，生产有机肥，以及减少温室气体排放。虽然消化过程在减少病原体和破坏有机物方面是有效的，但固体物质减少50%往往很难实现。因此，具有前处理和不同消化组合(即阶段消化)的先进消化工艺近年来受到了人们的关注。此外，大量的氨和磷被释放到消化器中，通过对废弃污泥的水解，这可能会降低污水处理厂的最终出水水质。因此，序贯硝酸铵/好氧(Aero)污泥消化工艺比单级硝酸铵消化工艺具有许多优点(例如更高的固形物/病原体杀灭率、氨去除、气味减少和更好的脱水性能)，因此被推荐使用。温哥华麦德龙和UBC生物反应器技术集团最近完成了NSERC Engage项目(A阶段)，该项目指出了顺序AN/Aero组合相对于Annacis当前的AN消化池配置的显著优势。这项建议(B阶段)的主要目标是在配备用于溶解氧(DO)设定点控制的自动气流控制阀的大型自动发酵罐中验证这些有益效果。如果B阶段的结果证实了这些优势，温哥华大都会将可以选择将一些现有的流动AN容器转换为Aero/ANOX污泥消化池，以在Annacis运行AN/Aero/ANOX组合系统。除了常规的消化性能参数外，B阶段还将评估一组选定药物在消化器中的命运。所获得的知识将导致不列颠哥伦比亚省(如西北兰利)和加拿大污水处理厂的其他生物固体转化为能源和最大限度减少废物的机会。它将培养专门领域的高素质人才(HQP)。

In Canada, medium-to-large scale municipal wastewater treatment plants (WWTPs) have been adapting anaerobic (AN) digestion technologies to generate energy in the form of biogas (60-75% methane) from wastewater sludge. Other benefits of AN digestion are diversion of organic waste from landfills, reduction of pathogens and odour, production of organic fertilizer, and reduction of greenhouse emissions. While AN digestion process is effective for reducing pathogens and destroying organic matter, solids reduction above 50% is often difficult to achieve. Therefore, advanced AN digestion processes with pretreatments and different digestion combinations (i.e. stage digestion) have gained interest in recent years. Furthermore, substantial ammonia and phosphate are released in AN digesters through hydrolysis of waste sludge which can degrade the final effluent quality of a WWTP. Therefore, sequential AN/ aerobic (AERO) sludge digestion process has been recommended due to many additional advantages (e.g. higher solids/pathogen destruction, ammonia removal, odour reduction and better dewaterability) over the single-stage AN digestion. Metro Vancouver and UBC Bioreactor Technology Group have recently completed an NSERC ENGAGE project (Phase A) that pointed out significant advantages of the sequential AN/AERO combination over the current AN digester configuration at Annacis. The main objective of this proposal (Phase B) is to verify these beneficial effects in larger-scale automated fermenters with automated air flow control valves for dissolved oxygen (DO) set-point control. If results from Phase B confirm the advantages, Metro Vancouver will have the option to convert some of the existing flow-through AN vessels to AERO/ANOX sludge digesters to operate a combined AN/AERO/ANOX system at Annacis. In addition to conventional digestion performance parameters, Phase B will also evaluate the fate of a group selected pharmaceuticals in digesters. The knowledge gained will lead to other biosolids-to-energy conversion and waste minimization opportunities at WWTPs in BC (e.g. Northwest Langley) and Canada. It will train highly qualified personnel (HQP) in a specialized field.