Micro-environment characteristics and microbial communities in activated sludge flocs of different particle size.

Microorganisms in activated sludge flocs (ASF) play important roles in the wastewater treatment process. However, the interplay between micro-environmental variation and microbial responses within ASF is poorly understood. In this study, microelectrodes and molecular culture-independent techniques were applied to detect the internal environment, microbial composition, and distribution in flocs with different particle size. Results showed dissolved oxygen (DO) concentrations within the center of the flocs were less than at the surface, and the DO concentration distributions were distinct in flocs of different particle size. With floc particle size increasing from 100 to 250 μm, the DO concentrations in the floc centers decreased 10-55%, respectively, while no distinct change was observed in flocs of less than 100 μm. Similar phenomenon occurred for the distributions of NH(4)(+) and NO(3)(-) in flocs. Microbial structure indicated bacterial compositions and distributions were heterogeneous and responded to micro-environment variation in flocs of different particle size.

[1]  Baikun Li,et al.  Micro-profiles of activated sludge floc determined using microelectrodes. , 2004, Water research.

[2]  J. Li.  In situ identification of azo dye inhibition effects on nitrifying biofilms using microelectrodes , 2002 .

[3]  Mujalin K Pholchan,et al.  Systematic study of the effect of operating variables on reactor performance and microbial diversity in laboratory-scale activated sludge reactors. , 2010, Water research.

[4]  Imre Takács,et al.  Modelling of the micromorphology of the activated sludge floc: Low do, low F/M bulking , 1995 .

[5]  R. Amann,et al.  Community Structure and Activity Dynamics of Nitrifying Bacteria in a Phosphate-Removing Biofilm , 2001, Applied and Environmental Microbiology.

[6]  K. Schleifer,et al.  Probing activated sludge with oligonucleotides specific for proteobacteria: inadequacy of culture-dependent methods for describing microbial community structure , 1993, Applied and environmental microbiology.

[7]  Ying-xu Chen,et al.  Correlation of reactor performance and bacterial community composition during the removal of trimethylamine in three-stage biofilters , 2008 .

[8]  E. Ferreira,et al.  Mass transfer properties of glucose and O2 in Saccharomyces cerevisiae flocs , 1998 .

[9]  P. Bishop,et al.  Stratification and Oxidation–Reduction Potential Change in an Aerobic and Sulfate‐Reducing Biofilm Studied Using Microelectrodes , 2001, Water environment research : a research publication of the Water Environment Federation.

[10]  Lei Wang,et al.  Micro-analysis of nitrogen transport and conversion inside activated sludge flocs using microelectrodes , 2011 .

[11]  Y. Watanabe,et al.  Evaluation of the impact of bioaugmentation and biostimulation by in situ hybridization and microelectrode. , 2003, Water research.

[12]  A. E. Greenberg,et al.  Standard methods for the examination of water and wastewater : supplement to the sixteenth edition , 1988 .

[13]  Ju-Hyun Kim,et al.  Anaerobic/oxic/anoxic granular sludge process as an effective nutrient removal process utilizing denitrifying polyphosphate-accumulating organisms. , 2006, Water research.

[14]  Yongzhen Peng,et al.  Nitritation and denitritation of domestic wastewater using a continuous anaerobic-anoxic-aerobic (A(2)O) process at ambient temperatures. , 2010, Bioresource technology.

[15]  Duu-Jong Lee,et al.  Oxygen Diffusion in Single Sludge Floc , 2008 .

[16]  George F Wells,et al.  Fine-scale bacterial community dynamics and the taxa-time relationship within a full-scale activated sludge bioreactor. , 2011, Water research.

[17]  Yongzhen Peng,et al.  Long-term effect of dissolved oxygen on partial nitrification performance and microbial community structure. , 2009, Bioresource technology.

[18]  Duu-Jong Lee,et al.  Structural analysis of sludge flocs , 2004 .

[19]  Paul Lant,et al.  Modelling activated sludge flocculation using population balances , 2002 .

[20]  M. Wagner,et al.  The microbial community composition of a nitrifying-denitrifying activated sludge from an industrial sewage treatment plant analyzed by the full-cycle rRNA approach. , 2002, Systematic and applied microbiology.

[21]  R. Qi,et al.  Comparison of bacterial community structures in two systems of a sewage treatment plant using PCR-DGGE analysis. , 2011, Journal of environmental sciences.

[22]  Cristian Picioreanu,et al.  Three-dimensional dual-morphotype species modeling of activated sludge flocs. , 2004, Environmental science & technology.

[23]  Markus Schmid,et al.  Characterization of activated sludge flocs by confocal laser scanning microscopy and image analysis. , 2003, Water research.

[24]  J. C. van den Heuvel,et al.  Microscale Distribution of Populations and Activities ofNitrosospira and Nitrospira spp. along a Macroscale Gradient in a Nitrifying Bioreactor: Quantification by In Situ Hybridization and the Use of Microsensors , 1999, Applied and Environmental Microbiology.

[25]  Kulchaya Tanong,et al.  Microbial community analysis of an aerobic nitrifying-denitrifying MBR treating ABS resin wastewater. , 2011, Bioresource technology.

[26]  P. Lant,et al.  Impacts of morphological, physical and chemical properties of sludge flocs on dewaterability of activated sludge , 2004 .

[27]  John W. Shanahan,et al.  Influence of a nitrifying biofilm on local oxygen fluxes across a micro-porous flat sheet membrane , 2006 .

[28]  D. G. Allen,et al.  Effects of transient temperature conditions on the divergence of activated sludge bacterial community structure and function. , 2007, Water research.

[29]  Bassim Abbassi,et al.  Minimization of excess sludge production by increase of oxygen concentration in activated sludge flocs; experimental and theoretical approach , 2000 .

[30]  Jun-xin Liu,et al.  Simultaneous removal of hydrogen sulfide and toluene in a bioreactor: performance and characteristics of microbial community. , 2011, Journal of environmental sciences.

[31]  J. Tay,et al.  Size-dependent anaerobic digestion rates of flocculated activated sludge: role of intrafloc mass transfer resistance. , 2005, Journal of environmental management.

[32]  Baikun Li,et al.  Modeling of the microenvironment of activated sludge floc with experimental and theoretical methods , 2003 .