The effect of different aeration conditions in activated sludge--Side-stream system on sludge production, sludge degradation rates, active biomass and extracellular polymeric substances.

On-site minimization of excess sludge production is a relevant strategy for the operation of small-scale and decentralized wastewater treatment plants. In the study, we evaluated the potential of activated sludge systems equipped with side-stream reactors (SSRs). This study especially focused on how the sequential exposure of sludge to different aeration conditions in the side-stream reactors influences the overall degradation of sludge and of its specific fractions (active biomass, extracellular polymeric substances (EPS), EPS proteins, EPS carbohydrates). We found that increasing the solid retention time from 25 to 40 and 80 days enhanced sludge degradation for all aeration conditions tested in the side-stream reactor. Also, the highest specific degradation rate and in turn the lowest sludge production were achieved when maintaining aerobic conditions in the side-stream reactors. The different sludge fractions in terms of active biomass (quantified based on adenosine tri-phosphate (ATP) measurements), EPS proteins and EPS carbohydrates were quantified before and after passage through the SSR. The relative amounts of active biomass and EPS to volatile suspended solids (VSS) did not changed when exposed to different aeration conditions in the SSRs, which indicates that long SRT and starvation in the SSRs did not promote the degradation of a specific sludge fraction. Overall, our study helps to better understand mechanisms of enhanced sludge degradation in systems operated at long SRTs.

[1]  C. W. Randall,et al.  The effect of iron dosing on reducing waste activated sludge in the oxic-settling-anoxic process. , 2015, Bioresource technology.

[2]  Guang-Hao Chen,et al.  Effect of low ORP in anoxic sludge zone on excess sludge production in oxic-settling-anoxic activated sludge process. , 2003, Water research.

[3]  R. Goel,et al.  Evaluation of simultaneous nutrient removal and sludge reduction using laboratory scale sequencing batch reactors. , 2009, Chemosphere.

[4]  Bruce E Rittmann,et al.  Non-steady state modeling of extracellular polymeric substances, soluble microbial products, and active and inert biomass. , 2002, Water research.

[5]  J. Novak,et al.  The Digestibility of Waste Activated Sludges , 2006, Water environment research : a research publication of the Water Environment Federation.

[6]  Mogens Henze,et al.  Activated sludge models ASM1, ASM2, ASM2d and ASM3 , 2015 .

[7]  C. W. Randall,et al.  The Influence of Sludge Interchange Times on the Oxic‐Settling‐Anoxic Process , 2010, Water environment research : a research publication of the Water Environment Federation.

[8]  Y. Comeau,et al.  Biodegradation of the endogenous residue of activated sludge in a membrane bioreactor with continuous or on-off aeration. , 2012, Water research.

[9]  H. Siegrist,et al.  The IWA Anaerobic Digestion Model No 1 (ADM1). , 2002, Water science and technology : a journal of the International Association on Water Pollution Research.

[10]  T. Lessie,et al.  Multiple Forms of Pseudomonas multivorans Glucose-6-Phosphate and 6-Phosphogluconate Dehydrogenases: Differences in Size, Pyridine Nucleotide Specificity, and Susceptibility to Inhibition by Adenosine 5′-Triphosphate , 1972, Journal of bacteriology.

[11]  C. G. Martínez-García,et al.  Aerobic stabilization of biological sludge characterized by an extremely low decay rate: modeling, identifiability analysis and parameter estimation. , 2014, Bioresource technology.

[12]  R. Goel,et al.  Carbon mass balance and microbial ecology in a laboratory scale reactor achieving simultaneous sludge reduction and nutrient removal. , 2014, Water research.

[13]  J. Novak,et al.  Biological Solids Reduction Using the Cannibal Process , 2007, Water environment research : a research publication of the Water Environment Federation.

[14]  Gianni Andreottola,et al.  Sludge Reduction Technologies in Wastewater Treatment Plants , 2010 .

[15]  Wenshan Guo,et al.  Sludge cycling between aerobic, anoxic and anaerobic regimes to reduce sludge production during wastewater treatment: performance, mechanisms, and implications. , 2014, Bioresource technology.

[16]  P Foladori,et al.  Concerning the role of cell lysis-cryptic growth in anaerobic side-stream reactors: the single-cell analysis of viable, dead and lysed bacteria. , 2015, Water research.

[17]  Alain Grasmick,et al.  Sequencing versus continuous membrane bioreactors: Effect of substrate to biomass ratio (F/M) on process performance , 2008 .

[18]  K. Svardal,et al.  Energy requirements for waste water treatment. , 2011, Water science and technology : a journal of the International Association on Water Pollution Research.

[19]  T. Mino,et al.  Enzyme activities under anaerobic and aerobic conditions in activated sludge sequencing batch reactor , 1998 .

[20]  Bruce R. Johnson,et al.  The use of ASM based models for the simulation of biological sludge reduction processes , 2008 .

[21]  Yves Comeau,et al.  Modelling the degradation of endogenous residue and 'unbiodegradable' influent organic suspended solids to predict sludge production. , 2013, Water science and technology : a journal of the International Association on Water Pollution Research.

[22]  Hansruedi Siegrist,et al.  Reduction of biomass decay rate under anoxic and anaerobic conditions , 1999 .

[23]  K. Park,et al.  Investigation of the sludge reduction mechanism in the anaerobic side-stream reactor process using several control biological wastewater treatment processes. , 2011, Water research.

[24]  P. Etienne,et al.  A high yield multi-method extraction protocol for protein quantification in activated sludge. , 2008, Bioresource technology.

[25]  J. Novak,et al.  Mechanisms of floc destruction during anaerobic and aerobic digestion and the effect on conditioning and dewatering of biosolids. , 2003, Water research.

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

[27]  H. D. Stensel,et al.  Wastewater Engineering: Treatment and Reuse , 2002 .

[28]  M. Coma,et al.  Minimization of sludge production by a side-stream reactor under anoxic conditions in a pilot plant. , 2013, Bioresource technology.

[29]  W. Gujer,et al.  Activated sludge model No. 3 , 1995 .