Sludge Densification and Low DO BNR: Anaerobic Selectors are the Key!

Sludge Densification and Low DO BNR: Anaerobic Selectors are the Key!AbstractIntensification of wastewater treatment aims to create higher treatment capacity while reducing energy demand. Low dissolved oxygen (DO) operation can reduce energy costs, but there are concerns about process performance, particularly sludge settleability. Three phases of experimentation were completed on two bench-scale treatment configurations to compare sludge settleability and microbial kinetic rates: 1. High DO, 2. Low DO and 3. Low DO, with an extended anaerobic HRT. Excellent sludge settleability was obtained in the A/O configuration (average SVI 83 ± 5 mL/g) at low DO concentrations of 0.3 – 0.6 mg/L. Whereas, an A2 /O configuration experienced filament growth and sludge bulking. When the HRT was increased to 1.5 hour anaerobic HRT and 0.5 hour anoxic HRT, the A2 /O train was able to achieve good sludge settleability (average SVI 101 ± 7 mL/g).Low dissolved oxygen (DO) operation is an attractive approach compared to typical aeration levels of 1.5 - 2 mg/L. However, there are concerns for process performance, specifically sludge settleability and lower microbial kinetic rates. Two bench-scale treatment plant configurations (A2/O and A/O) were operated at high and low DO. An Excellent sludge settleability (SVI 101  7 mL/g) was achieved at low DO concentrations with a longer anerobic HRT of the selector zone.SpeakerSturm, BelindaPresentation time14:30:0014:45:00Session time13:30:0015:00:00SessionAdvancing Low-energy Biological Nitrogen and Phosphorus Removal Through Low DO OperationSession locationRoom N426b - Level 4TopicAdvanced Level, Municipal Wastewater Treatment Design, NutrientsTopicAdvanced Level, Municipal Wastewater Treatment Design, NutrientsAuthor(s)Sturm, BelindaAuthor(s)B. Sturm ¹; M. Wittman ¹ ; Y. Hiripitiyage ²; J. Jimenez ³;Author affiliation(s)University of Kansas ¹; University of Kansas ¹ ; University of Kansas ²; Brown and Caldwell ³;SourceProceedings of the Water Environment FederationDocument typeConference PaperPublisherWater Environment FederationPrint publication date Oct 2023DOI10.2175/193864718825159077Volume / Issue Content sourceWEFTECCopyright2023Word count12