Hiroki ITOKAWA (Japan Sewage Works Agency)

1. Presentation for BIOMATH, Gent University (12/12/2005) Japanese situation on practical application of activated sludge modelsto municipal WWTPs Hiroki ITOKAWA(Japan Sewage Works Agency)

2. ● Contents Ø Present status of Japanese municipal WWTPs Ø Present status of practical application of simulation in Japan Ø Japanese guideline for practical application of activated sludge model

3. Ø Affiliation: Asteroid ITOKAWA 540m×270m×210m 2 billion km from the earth Photo from 8km distance by "Hayabusa" (http://www.jaxa.jp) Asteroid ITOKAWA 540m×270m×210m 2 billion km from the earth Photo from 8km distance by "Hayabusa" (http://www.jaxa.jp) (Original) Research & Technology Development Division,Japan Sewage Works Agency (JS), Japan (Temporal) ISA (Institute of Environmental Engineering),RWTH Aachen University, Germany* As a guest researcher with "Engineer Exchange Program" between RWTH and JS. Image of space-probe "Hayabusa" approaching ITOKAWA (http://www.jaxa.jp) Image of space-probe "Hayabusa" approaching ITOKAWA (http://www.jaxa.jp) ● About the speaker... Ø Name: Hiroki Itokawa (糸川 浩紀)

4. Ø Projects in JS: - COD removal by ozonation and BAC - Cascade denitrification-nitrification process - Hybrid N removal processes by attached growth media - Sludge disintegration processes by ozonation or thermophilic bacteria - Membrane bioreactor - New control technologies for BNR - ACTICATED SLUDGE MODELLING ● About the speaker... Ø Background: 1998 Ph.D. degree at Dept. Sanitary and Environmental Eng.,Univ. Tokyo 1998 ~ Lecturer at the same department, Univ. Tokyo 2000 ~ Engineer at R&D Division, JS 2005 ~ Guest researcher at ISA, RWTH Aachen Univ.

5. 1,900 km N 9,500 km 1,300 km Tokyo ● About Japan Ø Land area : 378,000 km2 (80% is mountainous) Ø Population : 127.655 millionpeople(07/2005) Ø Population density : 338 people/km2(average) * For "inhabitable" land, it's more than1,600! (Tokyo: 5,700) Ø Temperature : 5～27 ℃ (monthly average in Tokyo) Ø Precipitation : 1,700 mm/yr (average)

6. Sewered Sewage system (under the Ministry of Land, Infrastructure and Transport) 65% 76% Rural Sewerage Project (under the Ministry of Agriculture, Forestry and Fisheries) 3% Johkaso (on-site household wastewater treatment tank) 8% 24% 15% Nightsoil treatment Others Total population (127 million) 9% Not sewered (2002) ● Fate of domestic wastewater in Japan

7. Process Plant Capacity [thousand m3/d] < 5 5 - 10 10 - 50 50 - 100 100-500 > 500 Total Conventional AS Conventional AS 43 42 59 56 306 309 126 113 134 132 16 16 683 669 Step Aeration 1 6 8 5 20 O2 Aeration 1 1 3 2 4 11 AS for C Removal Oxidation Ditch Oxidation Ditch 586 677 79 77 40 36 699 796 Extended Aeration 27 5 2 34 SBR 64 5 4 73 High-Rate Aeration 5 1 6 RBC 13 4 5 1 23 High-Rate Trickling Filter 2 2 4 Biofilm Contact Aeration 24 24 Biological Aerated Filter 24 3 27 Biological Anaerobic-Aerobic Filters 22 22 Other C removal Processes 10 2 7 2 8 29 C removal + Precipitation 1 3 4 3 11 Nutrient Removal Pre-Denitrification (MLE) 4 2 1 3 10 Total 929 162 407 153 178 16 1,845 Anaerobic-Oxic Anaerobic-Anoxic-Oxic (A2O) 16 2 1 1 15 6 9 15 5 56 14 ● WWT processes used in Japan (2003)

8. ● Outline of Japanese municipal WWT ØTask of municipalities, but central government (MLIT)has still power (approval, subsidy, etc.) ØFull-coverage of sewer system in big cities.(CSO and up-grade to BNR is principal concern.) Ø New plants are exclusively for small municipalities,although sewer system is not always the best choice.

9. Ø The number of BNR plants is still small, but increasing. - Cascade D-N + precipitation - A2O - MBR (+ precipitation) - A/O - MLE + precipitation ● Outline of Japanese municipal WWT ØCAS and OD are predominant for C-removal,due to strong design guideline and "standardization". Ø Virtually, "DO control" is the only measure used for on-line control of aeration tank. ØEnergy recovery from influent/sludge (e.g. digestion) isnot popular (only in 40 plants).

10. Category [mg/L] Treatment process to be used T-BOD5 < 15 Any processes < 10 + sand filtration T-N < 20 MLE or A2O < 10 + C-addition T-P < 3 AO, A2O < 1 MLE + precipitation + sand filtration < 0.5 A2O + precipitation + sand filtration * Applied to daily maximum effluent concentration. * Only BOD5 is essential. T-N and T-P are optional. ● Effluent regulation for WWTPs Ø Regulation criteria were changed drastically in 2004(from "universal" to "site-specific" regulation).

11. ● Effluent regulation for WWTPs Ø New administrative "emission trade"-like frame will be implemented soon for N & P removal. Every WWTP discharging to specified closed water body is assigned the amount of N &P reduction. Plant A: Oh, we can't reduce such amount with these old facilities! Plant B: OK! We can reduce extra amount! Instead, give me money! Plant A: ...OK. It's cheaper than up-grading...

12. ● What's JS ? ØA governmental agency under the Ministry of Land, Infrastructure and Transport (MLIT). Ø Established in 1972, according to specific law. Ø About 800 staffs, including 350 engineers. Ø Principal task is design, construction, and operational assist of municipal WWTPs at the request of municipalities. ØR&D Division deals with development and evaluation of new technologies concerning WWT and sludge management, as well as survey of existing WWTPs. Ø It is not a guideline-making organization, but our reports have been principal data source for Japanese guidelines.

13. - Aerobic SRT as a function of temperature (empirical relationship). Aerobic tank - Denitrification rate as a function of BOD-SS loading (empirical relationship). Anoxic tank Anaerobic tank - Just HRT ! Dynamic simulation with activated sludge model ??? Secondary clarifier - Surface loading. Ø No kinetics, poor mass-balance. Ø No prediction of EBPR, poor prediction of denitrification. Ø Difficult to consider dynamic condition(e.g. influent fluctuation, storm event, etc.) ● Existing design criteria in Japan

14. Municipalities are getting involved. 'ASM ! I 'm interested in it ! But how can I use it ?' Consultants started to try to use. 'ASM... Oh, I've heard about that !' Only a very small community. 'ASM? What is it ?' 18 16 Start of JS Project 14 12 10 No. presentations 8 6 4 2 The number of ASM-related presentations in the Annual JSWA Conference 0 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 Year ● Trends on ASM in Japan

15. Municipalities (or JS) - Play a key role because they make an order. - Large cities began to use, but most of the engineers are still skeptical about "predicting power" of model. Consultants - Also important, since they could be the main user. - Large companies have a few model users, and they are just waiting for the publication of guideline. Electricmanufacturers - There are some "heavy" model uses, traditionally, but experience on biological issues is often lacking. - Concern is mainly towards process control. Machinery suppliers - Most of large companies have a few model users. - Evaluation of their own product/system is the major application. Universities - Few researchers deal with ASM at the moment. - "Our role has been finished." ● Present status of ASM in Japan Ø At least the name is known to most of engineers in the field. Ø The number of users is still small (less than 50 persons?).

16. Ø Simulation software used in Japan: Japanese translation English - BioWin (OEC) - GPS-X (KURITA) - WEST (EMORI) - AQUASIM - SIMBA * Most of electric companies dealing with ASM have their own software, although principally for internal use. ● Present status of ASM in Japan Ø At the moment, only "trial use" . (As far as I know,) there are no project in which model was used really for practical purpose in the field of municipal WWTPs. Ø No integrated modelling approach.

17. ● What is the obstacle ? ØToo strong existing design guideline, in terms not only of design freedom, but also of evidence for audit inspection. ØPoor motivation for optimizing design/operation of WWTPs. ØLack of engineers who have BOTH "motivation to use models" and "experience of process engineering". ØAbsence of guideline for modelling study. ØLack of "good example" of practical application in Japan. Ø Use of CODMn, not CODCr. Ø English environment (e.g. IWA technical report, literatures, software, etc.).

18. ● Activity of R&D Division, JS on ASM Ø Since 2000. ØSurvey of influent characteristics in terms of ASM (correlation between CODCr and CODMn/BOD5, COD components). ØSampling campaigns for model calibration. Ø Calibration and simulation case studies to develop a model application procedure. Ø Development of simulation softwares. Ø Development of a guideline for practical use of models.

19. Ø Aims: - To ensure a certain level of simulation studies. - To be "a trigger" of model application in Japan. - To let the modelling study authorized. - To be implemented in general design guideline. ● JS Guideline of modelling Ø "Evaluation of the Method of Practical Application of Activated Sludge Model". Ø Supervised by a committee, headed by Prof. Mino, Univ. Tokyo.

20. ● JS Guideline of modelling Ø Basic ideas: - To be not only a guideline, but also a handbook. - Make it as simple as possible. - Calibration is essential for individual plant (no standard influent/parameter values) in most cases. - Additional data collection is necessary in most cases, but no lab-experiments for parameter estimation. - Not put too much stress on "predictability" of effluent qualities.

21. ● Contents of the report • Introduction • Detailed description of ASM • Application of ASM • Procedure of modelling study • Case studies • Future perspectives • Appendixes • Introduction • Detailed description of ASM • Application of ASM • Procedure of modelling study • Case studies • Future perspectives • Appendixes

22. - Biological model: ASM2d - Secondary clarifier model: not specified - Calibration: fitting to plant data (no lab-experiments) - Software: not specified 1. Problem/target definition 5. Process modelling 2. Existing data collection 6. Calibration/verification 3. Additional survey 7. Simulation 4. Process analysis 8. Evaluation/implementation ● Procedure of modelling study

23. 2. Existing data collection - Design documents - Historical operating data - Plant inspection and interview - Evaluation of data ● Procedure of ASM application 1. Problem/target definition - Overall and simulation objectives - Index for results evaluation/comparison - Required predicting accuracy - Range of investigation - Possible scenarios

24. 3. Additional survey ● Procedure of ASM application - Definition of target lane - Reactor/clarifier hydraulics - Oxygen supply by aeration devices - Clarifier sludge blanket - Daily average influent/effluent qualities - Diurnal fluctuation of influent/effluent - "Profile" of water quality of bioreactor - Water quality of return sludge - DO in aerobic reactor - Influent characterization (COD) - Sludge characterization (COD, N and P)

25. ● Procedure of ASM application 4. Processanalysis - "Representativity" check for calibration data - "Stability" check for calibration data - Mass balance check for calibration data - Estimating the amount of COD, N and P conversions - Estimating "phenomena" in each compartment of reactor and clarifier

26. Raw WW Effluent SC PS Excess sludge Return sludge Definition of the modelling range ● Procedure of ASM application 5. Process modelling Secondary clarifier - " Ideal clarifier" with/without reactions - Fixed return sludge concentrations Aeration - KLa model - DO control - Fixed DO Bioreactor - Tank-in-series model

27. ● Procedure of ASM application 6. Calibration - Determining simulation method (e.g. static or dynamic?, initial condition?), considering "representability" and "stability" of data. - Defining data sets to be used. - Setting all the information on simulator. - Sensitivity analysis, if possible. - Getting general idea of fitting from simulation result with "default" values. - Fitting to observed data by all the "unreliable" input data including parameters. - Verifying parameters with other data set(s), and evaluate simulation "reliability".

28. Solids production çInfluent COD (XI /XS ) Influent/solids N&P çConversion factors (fN and fP ) Nitrification çNitrifiers kinetics (μAUT, KO2, KNH4 ) çAeration, if DO data is not reliable Denitrification çXH anoxic kinetics (ηNO3, KO2 ) çHydrolysis anoxic kinetics (ηNO3, KO2 ) EBPR çXPAO kinetics (bPAO, qpp, qPHA, YPAO ) çHydrolysis anaerobic kinetics (ηfe ) çInfluent COD, RS NOx-N, if unreliable ● Procedure of ASM application Fitting to observed data

29. ● FAQ on modelling in Japan Ø By non model user: - How precise the model can predict effluent qualities ? - Do I have to understand all these (terrible) equations ? - How much cost is required as a whole ? - Can you predict specific phenomena (e.g. effluent solids conc., sludge bulking, storm event, etc.) ? Ø By model user: - How much data should I take for calibration ? - Which parameter should be changed in calibration andhow much extent ? - How much extent should I "fit" to the observed data ? - How can I have confidence on my calibration result ?

30. ● Future perspective Ø Limitation of existing design guideline is getting realized more and more. Ø A case where simulation study can make a contributionwill increase significantly. Ø Use of simulation study will increase anyway, but actual"launch" will be after implemented in general guideline. Ø Present method of calibration could be more "systematic" and "automatic", reducing efforts and deviation of results from person to person, where importance of verifying and evaluating the result has to be emphasized more and more. Ø Predictions of specific cases are also matters of concern(e.g. storm event, nightsoil addition, MBR, hybrid process, etc.) .

31. Thank youfor your kind attention !