Redox control bioreactor: A unique biological water processor

Abstract

The redox control bioreactor (RCB) is a new hollow fiber membrane bioreactor (HFMBR) design in which oxygen and hydrogen gases are provided simultaneously through separate arrays of juxtaposed hollow fiber (HF) membranes. This study applied the RCB for completely autotrophic conversion of ammonia to N(2) through nitrification with O(2) and denitrification using hydrogen as an electron donor (i.e., autohydrogentrophic denitrification). The hypothesis of this research was that efficient biofilm utilization of O(2) and H(2) at respective HFs would limit transport of these gases to bulk fluid, thereby enabling completely autotrophic ammonia conversion to N(2) through the co-occurrence of ammonia oxidation (O(2)-HF biofilms) and autohydrogenotrophic denitrification (H(2)-HF biofilms). A prototype RCB was fabricated and operated for 215 days on a synthetic, organic-free feedstream containing 217 mg L(-1) NH(4)(+)-N. When O(2) and H(2) were simultaneously supplied, the RCB achieved a steady NH(4)(+)-N removal flux of 5.8 g m(-2) day(-1) normalized to O(2)-HF surface area with a concomitant removal flux of 4.4 g m(-2) day(-1) (NO(3)(-))+NO(2)(-))-N based on H(2)-HF surface area. The significance of H(2) supply was confirmed by an increase in effluent NO(3)(-)-N when H(2) supply was discontinued and a decline in NO(3)(-)-N when H(2) supply was restarted. Increases in H(2) pressure caused decreased ammonia utilization, suggesting that excess H(2) interfered with nitrification. Microprobe profiling across radial transects revealed significant gradients in dissolved O(2) on spatial scales of 1 mm or less. Physiological and molecular analysis of biofilms confirmed that structurally and functionally distinct biofilms developed on adjacent, juxtaposed fibers.

Hydrogenotrophic denitrification of potable water: A review

“…Thus, membrane selection is a critical factor for the performance of this technology. Gas-permeable membranes are mainly composite membrane (e.g., sandwich structure) [5], polypropylene [13], polysulfone [92], platinum cured silastic [110] and silicone coated ferro-nickel slag [31]. Membrane biofilm reactors minimize the cost of supplying electron donor, because almost 100% utilization of H 2 is possible.…”

Circumventing kinetics in biogeochemical modeling

“…Analogously, SMF allows predicting the effects of hypothetically or putatively occurring reactions in an ecosystem without knowledge of kinetics, thus facilitating ecosystem engineering and assessing the potential role of metabolic pathways at ecosystem scales. For example, SMF could provide valuable predictions of maximum feasible biochemical flux rates during the design of spatially structured bioreactors (89), regardless of the eventual inhabiting microorganisms.…”

Biocatalytic membrane reactors for the removal of recalcitrant and emerging pollutants from wastewater

“…The hydrogen-based MBfR has been investigated for a range of oxidized contaminants present in water, for example nitrate (Ergas and Reuss, 2001 ;Lee and Rittmann, 2000 ), perchlorate , trichloroethene (Edstrom et al ., 2005 ), selenate (Chung et al ., 2006c ), arsenate (Chung et al ., 2006a ), chromate (Chung et al ., 2006b ) and bromate (Downing and Nerenberg, 2007a ). It has also been combined with oxygen-based MBfRs for nitrifi cation followed by hydrogenotrophic denitrifi cation (Cowman et al ., 2005 ;Hwang et al ., 2009aHwang et al ., , 2010Shin et al ., 2005Shin et al ., , 2008Smith et al ., 2008 ). The development of hydrogenbased MBfRs is reviewed in three papers (Celmer-Repin et al ., 2010 ;Chung et al ., 2006a ;Rittmann et al ., 2004 ).…”

“…The wastewater is either fed sequentially from the oxygen-based Polypropylene porous fl at sheet Reij et al ., 1995 ;Reij et al ., 1997 Toluene Polyethylene porous hollow fi bers Ergas and McGrath, 1997;Ergas et al ., 1999 Toluene Polysulfone porous hollow fi bers Parvatiyar et al ., 1996a Toluene PVDF coated with PDMS non-porous fl at sheet Jacobs et al ., 2004 Toluene Polyethylene porous hollow fi bers Kim and Kim, 2005 ;Song et al ., 2007 Toluene Polyacrylonitrile coated with PDMS non-porous fl at sheet Kumar et al ., 2008 ;Kumar et al ., 2009 Toluene, dichloromethane Polypropylene porous membrane Hartmans et al ., 1992 Livingston, 1994a;Livingston, 1994 1,2-dichloroethane Silicone rubber tubing Freitas dos Santos and Livingston, 1994 Toluene Silicone rubber tubing Emanuelsson et al ., 2003Phenol Polypropylene Chung et al ., 2004 Poly-dimethyl siloxane and poly-methyl-vinyl siloxane Xiao et al ., 2006 Phenol Polyvinylidene fl uoride Juang et al ., 2009 Benzene, toluene, and xylene Poly-dimethyl siloxane Mehdizadeh et al ., 2011 to the hydrogen-based MBfR or recirculated between the two modules (Cowman et al ., 2005 ;Hwang et al ., 2009aHwang et al ., , 2010Shin et al ., 2005Shin et al ., , 2008Smith et al ., 2008 ). Smith et al .…”