Abstract
Settling and Dewatering Characteristics of an A-stage Activated Sludge Process Proceeded by Shortcut Biological Nitrogen Removal
Highlights
Many water resource recovery facilities (WRRFs) have shifted their focus from just treating wastewater to reducing their physical footprint and external resource consumption, all while striving to obtain energy neutral operation and meet stringent discharge standards
The A-stage of the adsorption/ bio-oxidation (A/B) pilot was operated at a 30-minute hydraulic residence time (HRT) and the solids retention time (SRT) was maintained between 0.1-0.3 days accounting for effluent total suspended solids (TSS) and excluding solids present in the intermediate clarifier
Since the A-stage was operated at such low sludge ages, the newly produced biomass did not completely aggregate into settleable flocs resulting in lower TSS removal efficiencies
Summary
Many water resource recovery facilities (WRRFs) have shifted their focus from just treating wastewater to reducing their physical footprint and external resource consumption (i.e., supplemental carbon, energy, and alkalinity), all while striving to obtain energy neutral operation and meet stringent discharge standards. Many WRRFs must remove macronutrients (i.e., nitrogen and phosphorus), which is generally resource intensive and may require external carbon addition if sufficient influent organic carbon is not available for complete denitrification or biological phosphorus removal (BPR). Unlike conventional BNR systems, these processes typically require low influent organic carbon loads providing the opportunity to maximize carbon capture upstream for energy recovery via biogas production. The A-stage is a high-rate activated sludge (HRAS) process operated at a solids retention time (SRT) less than 1 day and approximately a 30-minute hydraulic residence time (HRT) resulting in 50-70% chemical oxygen demand (COD) capture and removal with low aeration energy input and minimal COD oxidation [6,7]. Since solids handling and disposal represents a significant portion (10-30%) of WRRFs’ operational and maintenance costs [9,10], it is critical that the solids handling characteristics, like settleability, thicken ability, and dewaterability, are well understood to reduce these costs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
