Derlon, Nicolas

Haber, Jonathan

Morgenroth, Eberhard

English

Engineering Conferences International

Engineering Conferences InternationalECI Digital ArchivesWastewater and Biosolids Treatment and Reuse:Bridging Modeling and Experimental Studies ProceedingsSpring 6-10-2014Aerobic conditions prevail over scarce aeration andstarvation conditions for activated sludgedegradationJonathan HaberSwiss Federal Institute of Aquatic Science and TechnologyEberhard MorgenrothSwiss Federal Institute of Aquatic Science and TechnologyNicolas DerlonSwiss Federal Institute of Aquatic Science and TechnologyFollow this and additional works at: http://dc.engconfintl.org/wbtr_iPart of the Environmental Engineering CommonsThis Conference Proceeding is brought to you for free and open access by the Proceedings at ECI Digital Archives. It has been accepted for inclusion inWastewater and Biosolids Treatment and Reuse: Bridging Modeling and Experimental Studies by an authorized administrator of ECI Digital Archives.For more information, please contact franco@bepress.com.Recommended CitationJonathan Haber, Eberhard Morgenroth, and Nicolas Derlon, "Aerobic conditions prevail over scarce aeration and starvation conditionsfor activated sludge degradation" in "Wastewater and Biosolids Treatment and Reuse: Bridging Modeling and Experimental Studies",Dr. Domenico Santoro, Trojan Technologies and Western University Eds, ECI Symposium Series, (2014). http://dc.engconfintl.org/wbtr_i/8Eawag: Swiss Federal Institute of Aquatic Science and Technology Minimizing excess sludge production in small scale, decentralized WWtreatment systems Jonathan Habermacher Prof. Eberhard Morgenroth Dr. Nicolas Derlon 2 Wastewater treatment in the future is diverse Centralized, large scale Decentralized, small scale www.stadt-zuerich.ch •www.busse-is.de Benefits: • Efficient (finances, energy) • Reliable by close monitoring  Benefits: • Limited sewer needs  Total cost for (2004, CH):    WWTP: 100 Euro p-1 yr-1  Sewer:  230 Euro p-1 yr-1 • Possibility for local fresh-water production, heat recovery   3 … and so are sludge treatment technologies  100 1000 10'000 100'000 1Mio 10Mio 8 6 4 2 0 Energy demand for wastewater treatment W/Person (1 W = 9 kWh/person.year) Aerobic sludge stabilization Anaerobic sludge digestion Treatment plant size, PE Treatment data from: Kolisch et al. (2010) KA 57(10), 1028-1032 4 Sludge handling in small scale, decentralized WWTP WWTP Characteristics  • Limited accessibility • Low monitoring and maintenance  Sludge handling requirements • Simple and reliable technology • Priority on Hygenization • Reliable operation • Low maintenance and service • Odor free  www.klaro.eu 5 Current practice and optimization  Current practice  Aerobic sludge stabilization + Low odor  + Low gas - Energy requirement - Storage volume   Sludge transporting + P-recovery + Energy recovery - Transportation - GHG-emission - Costs - Handling  www.klaro.eu Optimization potential  Enhanced sludge degradation → Smaller storage volume → Fewer transports    Not fully aerobic sludge degradation → Economy of energy   Effect of Solid Retention Time (SRT) on sludge reduction 6 Conditions for enhanced sludge degradation Spérandio et al. 2013,  WS&T (67), pp. 789-796 Review on membrane bioreactor studies studies ASM ASM + degradation XU,E  Finding SRT can be used for sludge reduction    Questions • Origin of variation in datapoints?  • Other control parameters than SRT?    Effect of Redox potential and Starvation on sludge reduction 7 Conditions for enhanced sludge degradation Key Parameter for sludge reduction Effective-ness Mechanism Questions Publications Low redox potential  (no or low level aeration, non methanogenic) variable • Iron reduction • Different compounds degradation • SRT vs. Redox effect? • Additional conditions? • Mechanism: in depth • Saby et al. 2003, Wat. Res. (37) • Novak et al. 2007, Wat. Env. Res. (79)  • Park et al. 2006, Wat. Env. Res. (78) • Chon et al. 2011, Wat. Res. (45),  • Ramdani et al. 2012, Wat. Res. (46) Starvation uncertain • Cryptic growth • Viral attack • Predation • Starvation effect? • Mechanism? Chon et al. 2011, Wat. Res. (45), pp. 6021-29 8 Research approach conditions Effects and mechanisms SRT Starvation Net sludge production Role of extracellular enzymes SB,Org XBio Redox potential XEPS XU,E Degradation rates of sludge fractions Biochemical composition of sludge fractions Endogenous processes 9 Investigating the effect of SRT, Aeration and Starvation    System low   System mid System high Phase 1 «SSRs aerobic» Phase 2 «SSRs scarce aeration» time Phases Layout Overall SRT  10 Effect of SRT and Aeration – Phase 1 «SSRs aerobic»  Expectation scarce aeration ORP-research ASM  11 Effect of SRT and Aeration – Phase 1 «SSRs aerobic»  Expectation scarce aeration Scarce aeration is not enhancing activated sludge degradation processes! Enhanced sludge degradation by starvation?  12 Effect of starvation - Methodology 1 Phase 1 «SSRs aerobic»  Measurement:  Volatile suspended solids (VSS) SB XBio XEPS XU,E Endogenous processes • Lysis • Cryptic growth • Predation • Viral attack • Cell maintenance • …    13 Effect of starvation – Simulation required Phase 1 «SSRs aerobic»  Laboratory systems Reactor model Inupt parameters Simulation platform: Aquasim Biokinetic model: ASM3,  Parameters:  Gujer et al. (2000), WS&T (39), pp. 183-193.  • Default Processes and Parameters • Degradation XU,E   Simulations Comparison 1. Sludge degradation in SSR Simulation scenarios  1  14 Effect of starvation – Results SSRs 1 Phase 1 «SSRs aerobic»  SRT  15 Effect of starvation – Results SSRs 1 Phase 1 «SSRs aerobic»  SRT  16 Effect of starvation – Results SSRs 1 Phase 1 «SSRs aerobic»  SRT Specific sludge degradation rate in SSRs is similar or slightly slower than ASM3 kinetics!   17 Effect of starvation – Simulation required Phase 1 «SSRs aerobic»  Laboratory systems Reactor model Inupt parameters Simulation platform: Aquasim Biokinetic model: ASM3,  Parameters:  Gujer et al. (2000), WS&T (39), pp. 183-193.   Simulations Comparison 1. Sludge degradation in SSR Simulation scenarios 2. Overall sludge degradation 3. Sludge degradation in the SBR  Degradation kinetics based on overall sludge production 18 Overall System degradation behavior Explanations differences X simulation errors X substrate (x) Measurement errors (x) pH Feeding mode (Novak et al. 2011, Biosolids and Residuals Lobos et al. 2008, J. of membrane science)  Degradation kinetics based on overall sludge production 19 Overall System degradation behavior Scenario 1: • bOHO=0.2 d-1 (default) • growth yield is different → YOHO=0.95 mg COD mg COD-1  Scenario 2:  • YOHO=0.54 mg COD mg COD-1 (default) • decay rate is different → bOHO=0.04 d-1          SBR and thus overall system sludge production are extraordinary high Summary o Aerobic SRT has the expected sludge reducing effect o Scarce aeration condition decreases the rate of endogenous processes o Energy-substrate starvation is not enhancing sludge degradation processes   Outlook o Mechanistic insights: Measurements of Active biomass, EPS, Enzymatic activities  Conclusion o Design of sludge minimization process: Aerobic SRT is most reliable and applicable in decentralized systems, e.g. aerated sludge storage is recommended o Use of electron acceptor limitation for sludge minimization: careful evaluation of working conditions and key mechanisms is still required o Filling mode of the activated reactor could impact on sludge production  … Minimization of excess sludge production in small scale decentralized WWtreatment systems 20 Closing 

Aerobic conditions prevail over scarce aeration and starvation conditions for activated sludge degradation

https://dc.engconfintl.org/cgi/viewcontent.cgi?article=1007&amp;context=wbtr_i

Aerobic conditions prevail over scarce aeration and starvation conditions for activated sludge degradation

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