Sewage sludge treatment in a thermophilic membrane reactor (TMR): factors affecting foam formation

Foam formation in the excess sludge treatment facilities of biological wastewater treatment plants (WWTPs) may represent a critical issue as it could lead to several operative problems and reduce the overall plant performance. This trouble also affects a novel technology recently proposed for sludge minimization, the thermophilic membrane reactor (TMR), operating with alternate aeration/non-aeration cycles. This technology, which has proven to be extremely resilient and suitable for treating industrial wastewater of different nature, demonstrated a high potential also as a solution for integrating existing WWTPs, aiming at the “zero sludge production.” In this work, an experimental study was conducted with a TMR pilot plant (fed daily with thickened sewage sludge) by adjusting the duration of aeration/non-aeration alternate cycles. Extracellular polymeric substance (EPS) concentration (and its soluble and bound fractions) has been monitored along with foaming power indices. The results highlight that foaming can be correlated to the presence of soluble protein fraction of EPS. Moreover, EPS production seems to be reduced by increasing the duration of the non-aeration cycles: optimal operating conditions resulted 2 h of aeration followed by 6 h of non-aeration. These conditions allow to obtain an EPS concentration of 500 mg L−1 with respect to 2300 mg L−1 measured at the beginning of experimental work.

[1]  B. Rittmann,et al.  A unified theory for extracellular polymeric substances, soluble microbial products, and active and inert biomass. , 2002, Water research.

[2]  J. Baudez,et al.  The viscoelastic behaviour of raw and anaerobic digested sludge: strong similarities with soft-glassy materials. , 2013, Water research.

[3]  Pierre Le-Clech,et al.  Fouling in membrane bioreactors used in wastewater treatment , 2006 .

[4]  N. Ren,et al.  Minimization of excess sludge production by in-situ activated sludge treatment processes--a comprehensive review. , 2013, Biotechnology advances.

[5]  S. Nicosia,et al.  Effect of chemical and biological surfactants on activated sludge of MBR system: microscopic analysis and foam test. , 2015, Bioresource technology.

[6]  B. Lim,et al.  Effects of operational parameters on aeration on/off time in an intermittent aeration membrane bioreactor , 2007 .

[7]  B. Subramanian,et al.  Mechanisms of foam formation in anaerobic digesters. , 2015, Colloids and surfaces. B, Biointerfaces.

[8]  G. Bertanza,et al.  High-strength wastewater treatment in a pure oxygen thermophilic process: 11-year operation and monitoring of different plant configurations. , 2015, Water science and technology : a journal of the International Association on Water Pollution Research.

[9]  Matthias Kraume,et al.  Filterability of activated sludge in membrane bioreactors , 2002 .

[10]  T. Curtis,et al.  A universal threshold concept for hydrophobic mycolata in activated sludge foaming. , 2008, Water research.

[11]  J. Tay,et al.  Strategy for minimization of excess sludge production from the activated sludge process. , 2001, Biotechnology advances.

[12]  B. Xie,et al.  Cause and pre-alarm control of bulking and foaming by Microthrix parvicella--a case study in triple oxidation ditch at a wastewater treatment plant. , 2007, Journal of hazardous materials.

[13]  B. Dong,et al.  Degradation of Extracellular Polymeric Substances (EPS) in Anaerobic Digestion of Dewatered Sludge , 2013 .

[14]  Giorgio Bertanza,et al.  Why use a thermophilic aerobic membrane reactor for the treatment of industrial wastewater/liquid waste? , 2015, Environmental technology.

[15]  S. I. Pérez-Elvira,et al.  Sludge minimisation technologies , 2006 .

[16]  O. H. Lowry,et al.  Protein measurement with the Folin phenol reagent. , 1951, The Journal of biological chemistry.

[17]  X. Qu,et al.  Influence of temperature and temperature shock on sludge properties, cake layer structure, and membrane fouling in a submerged anaerobic membrane bioreactor , 2012 .

[18]  Sean Tyrrel,et al.  Anaerobic digestion foaming causes--a review. , 2009, Bioresource technology.

[19]  Daniel B. Oerther,et al.  Quantifying filamentous microorganisms in activated sludge before, during, and after an incident of foaming by oligonucleotide probe hybridizations and antibody staining. , 2001, Water research.

[20]  Harlan G. Kelly,et al.  Autothermal thermophilic aerobic digestion (ATAD) — Part I: Review of origins, design, and process operation , 2007 .

[21]  Michele Torregrossa,et al.  Foaming in membrane bioreactors: identification of the causes. , 2013, Journal of environmental management.

[22]  F. Meng,et al.  Denitrification‐caused suppression of soluble microbial products (SMP) in MBRs used for biological nitrogen removal , 2013 .

[23]  G. Bertanza,et al.  Treatment of high strength pharmaceutical wastewaters in a Thermophilic Aerobic Membrane Reactor (TAMR). , 2014, Water research.

[24]  D. Jenkins,et al.  Causes and control of Nocardia in activated sludge. , 1990 .

[25]  L. Raskin,et al.  Role of filamentous microorganisms in activated sludge foaming: relationship of mycolata levels to foaming initiation and stability. , 2002, Water research.

[26]  Hanqing Yu,et al.  Extracellular polymeric substances (EPS) of microbial aggregates in biological wastewater treatment systems: a review. , 2010, Biotechnology advances.

[27]  L. Raskin,et al.  Long-term analysis of a full-scale activated sludge wastewater treatment system exhibiting seasonal biological foaming. , 2006, Water research.

[28]  K. Yu,et al.  Detailed investigation of the microbial community in foaming activated sludge reveals novel foam formers , 2015, Scientific Reports.

[29]  Giorgio Bertanza,et al.  Treatment of sewage sludge in a thermophilic membrane reactor (TMR) with alternate aeration cycles. , 2015, Journal of environmental management.

[30]  Raf Dewil,et al.  Advanced sludge treatment affects extracellular polymeric substances to improve activated sludge dewatering. , 2004, Journal of hazardous materials.

[31]  J. Nakajima,et al.  Measurement of Foam Quality of Activated Sludge in MBR Process , 2005 .

[32]  F. Smith,et al.  COLORIMETRIC METHOD FOR DETER-MINATION OF SUGAR AND RELATED SUBSTANCE , 1956 .

[33]  P. Bishop,et al.  Comparison of extraction methods for quantifying extracellular polymers in biofilms , 1999 .

[34]  C. F. Forster,et al.  A comparative study of the nature of biopolymers extracted from anaerobic and activated sludges , 1990 .

[35]  G. Bertanza,et al.  Integration between chemical oxidation and membrane thermophilic biological process. , 2010, Water science and technology : a journal of the International Association on Water Pollution Research.

[36]  Gaspare Viviani,et al.  The role of EPS concentration in MBR foaming: analysis of a submerged pilot plant. , 2011, Bioresource technology.