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

在加拿大，中到大规模的城市污水处理厂（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%甲烷）形式的能源。硝酸铵消化的其他好处是从垃圾填埋场转移有机废物，减少病原体和气味，生产有机肥料，减少温室气体排放。虽然AN消化过程对于减少病原体和破坏有机物是有效的，但是通常难以实现50%以上的固体减少。因此，近年来，具有预处理和不同消化组合（即阶段消化）的先进AN消化工艺引起了人们的兴趣。此外，大量的氨和磷酸盐通过水解废污泥在AN消化器中释放，这可以降低WWTP的最终流出物质量。因此，连续AN/好氧（AERO）污泥消化工艺已被推荐，由于许多额外的优点（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）比单级AN消化。

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.