Calibration and validation of model describing complete autotrophic nitrogen removal in granular sludge

Transcription

1 Downloaded from orbt.dtu.dk on: Jan 25, 2019 Calbraton and valdaton of model descrbng complete autotrophc ntrogen removal n granular sludge Vangsgaard, Anna Katrne; Mutlu, A. Gzem; Gernaey, Krst V.; Smets, Barth F.; Sn, Gürkan Publcaton date: 2012 Document Verson Publsher's PDF, also known as Verson of record Lnk back to DTU Orbt Ctaton (APA): Vangsgaard, A. K. (Author), Mutlu, A. G. (Author), Gernaey, K. (Author), Smets, B. F. (Author), & Sn, G. (Author). (2012). Calbraton and valdaton of model descrbng complete autotrophc ntrogen removal n granular sludge. Sound/Vsual producton (dgtal) General rghts Copyrght and moral rghts for the publcatons made accessble n the publc portal are retaned by the authors and/or other copyrght owners and t s a condton of accessng publcatons that users recognse and abde by the legal requrements assocated wth these rghts. Users may download and prnt one copy of any publcaton from the publc portal for the purpose of prvate study or research. You may not further dstrbute the materal or use t for any proft-makng actvty or commercal gan You may freely dstrbute the URL dentfyng the publcaton n the publc portal If you beleve that ths document breaches copyrght please contact us provdng detals, and we wll remove access to the work mmedately and nvestgate your clam.

2 Calbraton and valdaton of model descrbng complete autotrophc ntrogen removal n granular sludge Anna Katrne Vangsgaard a, A. Gzem Mutlu b, Krst V. Gernaey c, Barth F. Smets b and Gürkan Sn a a CAPEC - Chemcal and Bochemcal Engneerng DTU b Envronmental Engneerng DTU c PROCESS - Chemcal and Bochemcal Engneerng - DTU IWA Nutrent Removal and Recovery 2012: Trends n NRR September 23-25, Harbn, Chna

3 The case A granular sludge SBR performng N removal through ntrtaton/anammox Calbraton methodology developed Fast model ntalzaton Stochometrc rato evaluaton Purpose: Experment plannng Performance predcton for control applcatons 2 DTU Kemteknk, Danmarks Teknske Unverstet Præsentatonens navn

4 Methods Physcal system Sequencng batch operaton: Fll: Reacton: 10 mn. Settlng: 6 mn. Draw: Idle: 444 mn. consstng of three aerated phases and three nonaerated phases 10 mn. 10 mn. Reactor characterstcs: Volume: 4L Temperature: 30⁰C ph: 7.5±0.3 Mxng: 6 bladed Rushton mpeller at 80 rpm + bubble bbl aeraton Solds concentraton: 4.2 g VSS/L Ave. gran. sze: 50 µm Operatng tme: 11 months 3 DTU Kemteknk, Danmarks Teknske Unverstet Tme [mn] Fll Ar on Ar off Settle Draw Idle

5 Methods Model descrpton Boflm mass balance equatons Transport and mcrobal metabolsm Accumulaton = Inflow - Outflow + Generaton - Consumpton z CV t j A rv <=> C 1 2 t z z 2 zjc r dz ja ja (ja) rv u L 1. Transport of soluble compounds s governed by dffuson and of partculate compounds by advecton: S js Dbo, j Xu x X F 2. The granule radus s a functon of the growth and decay of bactera and a detachment process: Boflm A Bulk dl u dt F,L u D Where the advectve velocty s a functon of the growth of partculates on the nsde of a gven pont k: L n 1 k part r uf,k A k dz A 0 k 1 k 4 DTU Kemteknk, Danmarks Teknske Unverstet

6 Methods Model descrpton Bulk lqud mass balance equatons Transport and mcrobal metabolsm Accumulaton = Inflow - Outflow + Generaton - Consumpton C A C,bulk dc dt Q C Q C j A n,n out,bulk C V r C C,L Flux n and out of the boflm: AOB AnAOB 0 L L B Soluble speces j k S S S,bulk,L where k D L B Partculate speces j ux X D,L The mass transfer coeffcent s estmated from a sem-emprcal correlaton consderng mxng caused by bubble aeraton 5 DTU Kemteknk, Danmarks Teknske Unverstet

7 Methods Methodology development 6 DTU Kemteknk, Danmarks Teknske Unverstet

8 Methods Methodology development 7 DTU Kemteknk, Danmarks Teknske Unverstet

9 Results Steady state calbraton Step 1: Determne bulk lqud soluble N speces concentratons Step 2: Capturng overall reactor performance through fve evaluaton crtera: Three ratos and two effcences: NO2 NH4 2 R1 AOB vs. AnAOB + NOB relatve actvty NH4 R2 TN NO3 R3 NH 4 NH 4 E1 NH4,n TN E2 TN n AnAOB vs. AOB relatve actvty AnAOB vs. NOB relatve actvty Absolute mcrobal actvty 8 DTU Kemteknk, Danmarks Teknske Unverstet Mutlu et al., WWC Proceedngs

10 Results Steady state calbraton Step 3: Snce oxygen k L a could not be expermentally estmated, ths was calbrated based on the fve evaluaton crtera: k L a R1 R2 R3 NH 4+ removal TN removal d -1 ΔNO 2- /ΔNH 4+ ΔNH 4+ /ΔTN ΔNO 3- /ΔTN % % Smulaton Expermental Expermental values were obtaned as an average of one week of steady state operaton. Model was ntalzed by smulatng contnuous operaton for 1000 days, whch was then followed by 10 days of SBR operaton of whch the results from the last cycle were used for the steady state model evaluaton. 9 DTU Kemteknk, Danmarks Teknske Unverstet

11 Results Dynamc calbraton Step 4: Parameter subset dentfcaton Based on global senstvty analyss: µ max,aob K O2,AOB b AOB µ max,anaob K O2,AnAOB Y AnAOB d -1 gcod/m 3 d -1 d -1 gcod/m 3 gcod/gn Default value Lower bound Upper bound Step 5: In-cycle data collecton Samples from bulk lqud were manually collected every 15 mn. and analyzed for soluble N speces. Analyss results from three cycles were used for calbraton. 10 DTU Kemteknk, Danmarks Teknske Unverstet Vangsgaard et al., Boresource Technol.

12 Results Dynamc calbraton Step 6: Calbraton Based on pragmatc Monte Carlo method, whch was evaluated by WSSE: WSSE 2 m n y meas,k (t) y mod el,k (t, ) k1 1 k µ max,aob K O2,AOB b AOB µ max,anaob K O2,AnAOB Y AnAOB d -1 gcod/m 3 d -1 d -1 gcod/m 3 gcod/gn Default value Lower bound Upper bound Calbrated value However, all MC sms have an offset compared to the collected data Iteraton of step 4-6, n accordance wth the methodology 11 DTU Kemteknk, Danmarks Teknske Unverstet

13 Results Dynamc calbraton Step terated: Parameter subset and samplng space were expanded Calbrated Unt Default value Lower bound Upper bound value µ max,aob d K O2,AOB gcod/m b AOB d µ max,nob d K O2,NOB gcod/m b NOB d µ max,anaob d K O2,AnAOB gcod/m K HNO2,AnAOB gn/m e e e e-6 Y AOB gcod/gn Y AnAOB gcod/gn D NO2 m 2 /d 2.60e e e e-4 L B m 1.76e e e e-5 Among the new MC sms, the subset sample gvng the smallest error ftted much better to the data than the prevous. 12 DTU Kemteknk, Danmarks Teknske Unverstet

14 Results Valdaton Step 7: Data collecton for valdaton Samples were collected durng one cycle under slghtly dfferent condtons compared to the calbraton cycles. The solds concentraton was 4.4 g VSS/L and average granule sze was 35 µm. Step 8: Valdaton The valdaton was evaluated by the Janus coeffcent: J 1 n 1 n 2 val n val 1 n cal cal 1 y y t, meas, mod el y y t, meas, mod el 2 2 MAE RMSE Model output Calbraton Valdaton Calbraton Valdaton Janus coeffcent NH NO NO J s relatvely close to 1 for all model outputs, whch mples a good model ft. 13 DTU Kemteknk, Danmarks Teknske Unverstet

15 Perspectves The valdated model wll be used for two purposes: 1) desgn of future lab-scale experments n the form of perturbatons n the operaton 2) for predctng the process performance, whch s mportant n future optmzaton and process control applcatons and n up-scalng of the system Process optmzaton (based on results from Vangsgaard et al., 2012) Analyss on calbrated model 1.00 Removal effc cency RT [-] RO [(mgo2/l/d)/(mgn/l/d)] 14 DTU Kemteknk, Danmarks Teknske Unverstet Vangsgaard et al., Boresource Technol.

16 Perspectves 2) for predctng the process performance, whch s mportant n future optmzaton and process control applcatons and n up-scalng of the system Control mplementaton: Three dfferent control strateges have been developed and analyzed on the calbrated model. 1. Feedforward based on oxygen/ntrogen loadng rato (Vangsgaard et al., 2012) 3. Cascade control as a combnaton of 1. and Feedforward + feedback based on stochometrc rules (Mutlu et al., 2012): As future extenson of the current work, the developed control strategy wll be expermentally tested n the lab-scale reactors. 15 DTU Kemteknk, Danmarks Teknske Unverstet Vangsgaard et al., Boresource Technol. Mutlu et al., WWC Proceedngs

17 Conclusons/wrap-up p The model was successfully calbrated and valdated by followng a developed methodology: Frst, k L a was calbrated to long term steady state data by usng novel evaluaton crtera of stochometrc ratos ndcatng the relatve actvty of the mcrobal groups. Second, a subset of parameters were calbrated through dynamc calbraton to n-cycle data. An teraton of the second step was performed before a satsfactory result was obtaned. A fast and effcent novel ntalzaton process was developed Smulatng 1000 days of contnuous operaton before SBR operaton. The model s now beng used for optmzaton and control structure analyses. 16 DTU Kemteknk, Danmarks Teknske Unverstet

18 Thanks for your attenton! Acknowledgements to: All the supervsors and the Dansh Agency for Scence, Technology and Innovaton through the Research Centre for Desgn of Mcrobal Communtes n Membrane Boreactors ( ) ) for fundng of the project Contact nfo: E-mal: akv@kt.dtu.dk Phone: DTU Kemteknk, Danmarks Teknske Unverstet