Insight into the roles of packing carriers and ultrasonication in anaerobic side-stream reactor coupled membrane bioreactors: Sludge reduction performance and mechanism.

The sludge in situ reduction process by inserting an anaerobic side-stream reactor (ASSR) in a sludge return line provides a cost-effective approach to reduce sludge production in activated sludge systems. In this study, four pilot-scale membrane bioreactors (MBRs), including an AO-MBR for control, ASSR coupled MBR (ASSR-MBR), a MBR with ASSR packed with carriers (AP-MBR) and an AP-MBR with part of sludge ultrasonicated before fed into ASSR (AUP-MBR) were operated in parallel to investigate enhancing effects of ultrasonication and packing carriers on sludge reduction and pollutants removal performance under both normal and low temperature. Low temperature showed negligible impact on COD removal, deteriorated NH4+N and TN removal from 98.3% to 69.7% at 21.6 °C to 92.5% and 48.8% at 2.6 °C, and decreased sludge reduction efficiency (SRE) in ASSR-MBR. Packing carriers and ultrasonication both enhanced sludge reduction, especially under low temperature with SRE values increased from 8.2% of ASSR-MBR to 17.1% of AP-MBR and 32.6% of AUP-MBR at 4.5 ± 2.5 °C. Packing carriers and ultrasonication increased cell rupture by 11.1% and 14.5% in aerobic MBR, enhanced protease activity in ASSR by 60.0% and 116.3%, and reduced ATP content for heterotrophic metabolism by 31.4% and 7.3%, respectively. MiSeq sequencing results showed that packing carriers enriched hydrolytic bacteria (Terrimonas, Dechloromonas and Woodsholea), slow growers (Sulfuritalea, Thauera and Azospira) and predatory bacteria (Bdellovibrio and norank_Saprospiraceae), while ultrasonication further enriched hydrolytic bacteria (norank_Saccharibacteria and Ferruginibacter). Packing carriers is more cost-effective than ultrasonication to enhance sludge reduction by partial damage to bacterial cells and promoting better interaction between bacteria, enzymes and substrates to favor particles hydrolysis.

[1]  M. Coello,et al.  Evaluation of a biological wastewater treatment system combining an OSA process with ultrasound for sludge reduction. , 2017, Ultrasonics sonochemistry.

[2]  Barbara Kwiatkowska,et al.  Stimulation of bioprocesses by ultrasound. , 2011, Biotechnology advances.

[3]  M. Coello,et al.  Changes in enzymatic and microbiological activity during adaptation of a conventional activated sludge (CAS) to a CAS-oxic-settling-anaerobic (OSA) adapted process , 2016 .

[4]  P. Foladori,et al.  Anaerobic side-stream reactor for excess sludge reduction: 5-year management of a full-scale plant. , 2016, Journal of environmental management.

[5]  P Battistoni,et al.  Excess sludge reduction by biological way: from experimental experience to a real full scale application. , 2011, Bioresource technology.

[6]  Ying An,et al.  Microbial community structure of anoxic–oxic-settling-anaerobic sludge reduction process revealed by 454-pyrosequencing , 2015 .

[7]  Ying An,et al.  Effects of side-stream ratio on sludge reduction and microbial structures of anaerobic side-stream reactor coupled membrane bioreactors. , 2017, Bioresource technology.

[8]  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.

[9]  Lu-Man Jiang,et al.  Sludge reduction and microbial structures of aerobic, micro-aerobic and anaerobic side-stream reactor coupled membrane bioreactors. , 2018, Bioresource technology.

[10]  A. Sakanishi,et al.  Low ultrasonic stimulates fermentation of riboflavin producing strain Ecemothecium ashbyii , 2003 .

[11]  Zhen Zhou,et al.  Effects of potassium peroxymonosulfate on disintegration of waste sludge and properties of extracellular polymeric substances , 2016 .

[12]  M. Sarrafzadeh,et al.  Effect of nitrifiers community on fouling mitigation and nitrification efficiency in a membrane bioreactor , 2018, Chemical Engineering and Processing - Process Intensification.

[13]  Lu-Man Jiang,et al.  Effects of hydraulic retention time on process performance of anaerobic side-stream reactor coupled membrane bioreactors: Kinetic model, sludge reduction mechanism and microbial community structures. , 2018, Bioresource technology.

[14]  N. Ren,et al.  Economical evaluation of sludge reduction and characterization of effluent organic matter in an alternating aeration activated sludge system combining ozone/ultrasound pretreatment. , 2015, Bioresource technology.

[15]  J. Nielsen,et al.  Phylogenetic diversity and ecophysiology of Candidate phylum Saccharibacteria in activated sludge. , 2016, FEMS microbiology ecology.

[16]  L. Nghiem,et al.  Effects of sludge retention time on oxic-settling-anoxic process performance: Biosolids reduction and dewatering properties. , 2016, Bioresource technology.

[17]  Cheng Cheng,et al.  Correlation of microbial community structure with pollutants removal, sludge reduction and sludge characteristics in micro-aerobic side-stream reactor coupled membrane bioreactors under different hydraulic retention times. , 2018, Bioresource technology.

[18]  J. Mendoza-Roca,et al.  Changes in the process performance, sludge production and microbial activity in an activated sludge reactor with addition of a metabolic uncoupler under different operating conditions. , 2017, Journal of environmental management.

[19]  J. Degrève,et al.  Comparing glow discharge plasma and ultrasound treatment for improving aerobic respiration of activated sludge. , 2017, Water research.

[20]  Chuyang Y. Tang,et al.  Acute Responses of Microorganisms from Membrane Bioreactors in the Presence of NaOCl: Protective Mechanisms of Extracellular Polymeric Substances. , 2017, Environmental science & technology.

[21]  Zhichao Wu,et al.  Sludge reduction and process performance in a submerged membrane bioreactor with aquatic worms , 2011 .

[22]  R. Mahar,et al.  Effects of ultrasonic disintegration on sludge microbial activity and dewaterability. , 2009, Journal of hazardous materials.

[23]  Guang-hao Chen,et al.  A modified oxic-settling-anaerobic activated sludge process using gravity thickening for excess sludge reduction , 2015, Scientific Reports.

[24]  Yeo-Myeong Yun,et al.  Low-strength ultrasonication positively affects methanogenic granules toward higher AD performance: Hydrolytic enzyme excretions. , 2017, Ultrasonics sonochemistry.

[25]  Haneul Kim,et al.  Ferruginibacter yonginensis sp. nov., isolated from a mesotrophic artificial lake. , 2014, International journal of systematic and evolutionary microbiology.

[26]  P Pearce,et al.  Mechanical sludge disintegration for the production of carbon source for biological nutrient removal. , 2007, Water research.

[27]  J. Arévalo,et al.  Effect of temperature on membrane bioreactor performance working with high hydraulic and sludge retention time , 2014 .

[28]  P. Foladori,et al.  Bacteria permeabilization and disruption caused by sludge reduction technologies evaluated by flow cytometry. , 2010, Water research.

[29]  Xiang Zheng,et al.  Microbial responses to membrane cleaning using sodium hypochlorite in membrane bioreactors: Cell integrity, key enzymes and intracellular reactive oxygen species. , 2016, Water research.

[30]  Damien J Batstone,et al.  Low temperature treatment of domestic wastewater by purple phototrophic bacteria: Performance, activity, and community. , 2016, Water research.

[31]  J. Mendoza-Roca,et al.  The role of salinity on the changes of the biomass characteristics and on the performance of an OMBR treating tannery wastewater. , 2018, Water research.

[32]  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.

[33]  Wei Zhang,et al.  Simultaneous nitrification, denitrification and phosphorus removal in an aerobic granular sequencing batch reactor with mixed carbon sources: reactor performance, extracellular polymeric substances and microbial successions , 2018, Chemical Engineering Journal.

[34]  Beizhen Xie,et al.  Improvement of the activity of anaerobic sludge by low-intensity ultrasound. , 2009, Journal of environmental management.

[35]  N. Ren,et al.  Simultaneous waste activated sludge disintegration and biological hydrogen production using an ozone/ultrasound pretreatment. , 2012, Bioresource technology.

[36]  F. Ye,et al.  Effect of sludge retention time in sludge holding tank on excess sludge production in the oxic-settling-anoxic (OSA) activated sludge process , 2008 .

[37]  G. Valè,et al.  Distribution and activity of the anaerobic methanotrophic community in a nitrogen-fertilized Italian paddy soil. , 2016, FEMS microbiology ecology.

[38]  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.

[39]  A. Stintzi,et al.  Nitrifying moving bed biofilm reactor (MBBR) biofilm and biomass response to long term exposure to 1 °C. , 2014, Water research.

[40]  Zhen Zhou,et al.  Effects of dissolved oxygen on performance and microbial community structure in a micro-aerobic hydrolysis sludge in situ reduction process. , 2016, Water research.

[41]  Cheng Cheng,et al.  Enhancement of sludge reduction by ultrasonic pretreatment and packing carriers in the anaerobic side-stream reactor: Performance, sludge characteristics and microbial community structure. , 2018, Bioresource technology.