title: Bioflocculation management through high-rate contact-stabilization: A promising technology to recover organic carbon from low-strength wastewater.
abstract: A series of pilot-scale studies were performed to compare conventional high-rate activated sludge systems (HRAS) (continuous stirred tank reactor (CSTR) and plug flow (PF) reactor configurations) with high-rate contact-stabilization (CS) technology in terms of carbon recovery potential from chemically enhanced primary treatment effluent at a municipal wastewater treatment plant. This study showed that carbon redirection and recovery could be achieved at short solids retention time (SRT). However, bioflocculation became a limiting factor in the conventional HRAS configurations (total SRT ≤ 1.2 days). At a total SRT ≤1.1 day, the high-rate CS configuration allowed better carbon removal (52-59%), carbon redirection to sludge (0.46-0.55 g COD/g CODadded) and carbon recovery potential (0.33-0.34 gCOD/gCODadded) than the CSTR and PF configurations (28-37% COD removal, carbon redirection of 0.32-0.45 g COD/g CODaddedand no carbon harvesting). The presence of a stabilization phase (famine), achieved by aerating the return activated sludge (RAS), followed by low dissolved oxygen contact with the influent (feast) was identified as the main reason for improved biosorption capacity, bioflocculation and settleability in the CS configuration. This study showed that high-rate CS is a promising technology for carbon and energy recovery from low-strength wastewaters.
authors: Department of Civil & Environmental Engineering, The George Washington University, 800 22nd Street, NW, Washington, DC 20052, USA; DC Water, 5000 Overlook Ave., SW., Washington, DC 20032, USA. Electronic address: arifur@gwmail.gwu.edu.
authors: Arifur
authors: A
authors: Rahman
authors: Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
authors: Francis A
authors: FA
authors: Meerburg
authors: DC Water, 5000 Overlook Ave., SW., Washington, DC 20032, USA.
authors: Shravani
authors: S
authors: Ravadagundhi
authors: ARA Consult GmbH, Unterbergerstrasse 1, 6020 Innsbruck, Austria.
authors: Bernhard
authors: B
authors: Wett
authors: Brown and Caldwell, 2301 Lucien Way, Suite 250, Maitland, FL 32751, USA.
authors: Jose
authors: J
authors: Jimenez
authors: Hampton Roads Sanitation District, 1436 Air Rail Ave., Virginia Beach, VA 23455, USA.
authors: Charles
authors: C
authors: Bott
authors: DC Water, 5000 Overlook Ave., SW., Washington, DC 20032, USA.
authors: Ahmed
authors: A
authors: Al-Omari
authors: Department of Civil & Environmental Engineering, The George Washington University, 800 22nd Street, NW, Washington, DC 20052, USA.
authors: Rumana
authors: R
authors: Riffat
authors: DC Water, 5000 Overlook Ave., SW., Washington, DC 20032, USA.
authors: Sudhir
authors: S
authors: Murthy
authors: DC Water, 5000 Overlook Ave., SW., Washington, DC 20032, USA.
authors: Haydée
authors: H
authors: De Clippeleir
mesh_terms: D019149:Bioreactors; D002244:Carbon; D010100:Oxygen; D012722:Sewage; D014865:Waste Disposal, Fluid; D062065:Wastewater
chemical_list: D002244:Carbon; D010100:Oxygen; D012722:Sewage; D062065:Wastewater
keywords: Adsorption; Carbon capture; Energy neutrality; Extracellular polymeric substances; Municipal wastewater; Observed yield