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。

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.