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（WWTPs）一直在采用厌氧（AN）消化技术，从废水污泥中产生沼气（60-75%的甲烷）。氨氮消化的其他好处是转移垃圾填埋场的有机废物，减少病原体和气味，生产有机肥，减少温室气体排放。虽然消化过程对减少病原体和破坏有机物是有效的，但固体减少50%以上通常很难实现。因此，具有预处理和不同消化组合（即阶段消化）的先进氨氮消化工艺近年来引起了人们的兴趣。此外，大量的氨和磷酸盐通过废污泥的水解在氨氮沼气池中释放，这可以降低污水处理厂的最终出水质量。因此，由于与单级氨消化相比有许多额外的优点（例如，更高的固体/病原体破坏，氨去除，气味减少和更好的脱水性），因此推荐采用顺序氨/好氧（AERO）污泥消化工艺。大温哥华地区和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组合比Annacis目前的an消化器配置的显着优势。本提案（阶段B）的主要目标是在大型自动化发酵罐中验证这些有益效果，该发酵罐具有用于溶解氧（DO）设定点控制的自动空气流量控制阀。如果B阶段的结果证实了这些优势，大温哥华地区将可以选择将一些现有的通过AN容器转换为AERO/ANOX污泥消化器，以在Annacis运行AN/AERO/ANOX组合系统。除了常规消化性能参数外，B期还将评估消化器中一组选定药物的命运。所获得的知识将为卑诗省（例如西北兰利）和加拿大的污水处理厂带来其他生物固体到能源的转换和废物最小化的机会。它将培养一个专业领域的高素质人才。

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.