Beyond Energy Savings: A Deep Dive into Carbon Efficiency of Low DO BNR

Beyond Energy Savings: A Deep Dive into Carbon Efficiency of Low DO BNRAbstractThe Seneca Water Resource Recovery Facility (WRRF) uses a 5-stage Bardenpho process for nutrient removal, meeting strict regulations (< 0.2 mgN/L, Total Inorganic Nitrogen (TIN) < 2.0 mgN/L, and orthophosphate < 0.2 mgP/L. This success was attributed to simultaneous nitrification-denitrification (SND) and post-anoxic denitrification, facilitated by ABAC's regulation of dissolved oxygen (DO) levels. The test train achieved significant aeration savings and utilized internally stored carbon for post-denitrification under low DO conditions, eliminating the need for supplemental carbon. Analysis revealed that glycogen, more than polyhydroxyalkanoates (PHA), likely played a major role in this, aligning with the high abundance of glycogen-accumulating organisms (GAO), particularly Competibacter, and Tetrasphaera, the dominant phosphate-accumulating organism (PAO) observed. This system's efficiency suggests an innovative approach to carbon management for enhanced nutrient removal in wastewater treatment.DO was maintained at ~0.3 mg/L, lower than the usual ~1.5 mg/L. Low DO operation resulted in average effluent ammonia <0.2 mgN/L, <TIN of 1.5 mgN/L, and orthophosphate <0.2 mgP/L, without supplemental chemicals. High P uptake occurred even under low DO conditions, with enhanced nitrogen removal attributed to SND and post-anoxic denitrification. Moreover, specific denitrification rate tests showed higher rates at low DO, indicating efficient utilization of internally stored carbon.SpeakerRegmi, PuskerPresentation time09:30:0009:50:00Session time08:30:0010:00:00SessionLow Carbon BNR Fundamentals and ControlsSession locationRoom S502 - Level 5TopicAdvanced Level, Facility Operations and Maintenance, Municipal Wastewater Treatment Design, NutrientsTopicAdvanced Level, Facility Operations and Maintenance, Municipal Wastewater Treatment Design, NutrientsAuthor(s)Regmi, PuskerAuthor(s)P. Regmi 1; M. Johnson 2 ; C. Nguyen 3; A. Al-Omari 4; G. Wells 5; B. Yeakle 6; P. Regmi 1;Author affiliation(s)Brown and Caldwell 1; WSSC Water 2 ; WSSC Water 3; Brown and Caldwell 4; Northwestern University 5; WSSC Water 6; Brown and Caldwell 1;SourceProceedings of the Water Environment FederationDocument typeConference PaperPublisherWater Environment FederationPrint publication date Oct 2023DOI10.2175/193864718825159064Volume / Issue Content sourceWEFTECCopyright2023Word count14