MBBR Technology: - A cost effective solution for upgrading existing Waste water Treatment Works. Bruno Bigot

Transcription

1 MBBR Technology: - A cost effective solution for upgrading existing Waste water Treatment Works Bruno Bigot

2 Agenda 1. What is MBBR & How does it work? 2. Different MBBR configurations for upgrading existing WwTW 3. Q&A 2

3 What is MBBR? Combining the advantages of suspended growth and biofilm technologies MBBR = Moving Bed Biofilm Reactor Hybas = Hybrid Activated Sludge The core of the process is the biofilm carrier elements made from polyethylene with a density slightly below that of water These are designed to provide a large protected surface for the bacteria culture The biofilm carrier elements are kept suspended in the water by air from the diffusers in the aerobic reactors and by means of a mixer in the anoxic reactors HYBAS combines Biofilm & activated sludge

4 3 Key Elements Biofilm carrier elements Aeration/mixer system Retention sieves 1% Plastic 99% Know How

5 The Media

6 Aeration/Mixing Systems

7 The Retention Sieves Aerobic reactor sieves Anoxic reactor sieves

8 Reactors new or existing Circular Steel Reactors (Bolted or Welded) Rectangular/Circular open concrete reactors Circular fiber glass reactors Rectangular covered concrete reactors

9 MBBR Key Features & Benefits Very compact with strong ability to accept high loads Simple operation Robust biofilm process, recovers fast from acute toxicity and ph-shocks No clogging of reactors No sludge return no sludge bulking Low loading on the sludge separation stage Flexibility for reactor shape existing tanks or basins may be used The carrier elements can easily be pumped in and out of the reactor if desired

10 Different Configurations MBBR as sole biotreatment MBBR as pre-treatment MBBR as post-treatment MBBR in activated sludge (HYBAS/IFAS) Liquor Treatment - ANITAMox

11 Swansea Bay WwTW, AS into MBBR

12 Swansea Bay WwTW Upgrade of Activated Sludge Existing AS plant within a building 4 lanes. Need for extra capacity but no opportunity to increase the footprint of the plant The solution was to convert the AS into an MBBR (more compact): 4 lines of 2 reactors. Total volume of 4,720 m3 (2,360 m3 K5) Performance: MBBR guarantee < 10 mg/l of SBOD Performance test: SBOD out < 4.8 mg/l 12

13 Different Configurations MBBR as sole biotreatment MBBR as pre-treatment MBBR as post-treatment MBBR in activated sludge (HYBAS/IFAS) Liquor Treatment - ANITAMox

14 Roughing MBBR (BAS = MBBR + AS) - Kima Egypt

15 Kima 1 - Egypt Roughing MBBR prior to AS Kima 1: existing AS, capacity 21 MLD 35 MLD Increased COD load Increased Sludge Production Decreased SRT on AS Two needs 1) Remove a fraction of soluble COD (50%) upstream the AS 2) Improve the effluent TSS since direct discharge to the Nile Kima 1 Parameters Units Inlet Outlet Average flow m3/d BOD mg/l COD mg/l TSS mg/l MBBR ahead of the existing AS

16 Different Configurations MBBR as sole biotreatment MBBR as pre-treatment MBBR as post-treatment MBBR in activated sludge (HYBAS/IFAS) Liquor Treatment - ANITAMox

17 Cudworth WwTW, polishing MBBR + DF

18 Cudworth WwTW Polishing after trickling filters 2 Primary settlers + 3 Trickling filters + 2 Humus tanks Influent Characteristics to MBBR (outlet trickling filters) Parameter Units Value Average flow m 3 /d 2946 FFT m 3 /d 5440 BOD 5 load NH 4 -N load TSS load kg/d 74 mg/l 25 kg/d 44 mg/l 15 kg/d 118 mg/l 40 Design horizon for 2025 population equivalent of 10,693 Need for increased secondary capacity Need for improved nitrification capacity, BOD and solids removal Discharge Standard Parameter Unit Value Total BOD5 as Need 95%ile for an increased mg/l secondary 10 capacity (design horizon 2025) NH4-N as 95%ile mg/l 3 TSS as 95%ile mg/l 15 18

19 Cudworth WwTW Polishing after trickling filters Several options considered: Gravity flow activated sludge + discfilters Pumped flow activated sludge + discfilters Additional trickling filter/humus tank + MBBR + discfilters 2 stages because low NH 4 -N (< 3 mg/l) 1 st stage operates at higher residual NH 4 -N and higher nitrification rates 19

20 Cudworth WwTW Polishing after trickling filters NH4-N Units Yr Design 95%ile mg/l Actual 95%ile mg/l Average mg/l Max mg/l

21 Different Configurations MBBR as sole biotreatment MBBR as pre-treatment MBBR as post-treatment MBBR in activated sludge (HYBAS/IFAS) Liquor Treatment - ANITAMox

22 Veolia biofilm based solutions HYBAS or IFAS (MBBR in AS) Keep the sludge recirculation of the AS Media only in a fraction of the AS Fast growing bacteria (heterotrophs, aerobic & denitrifiers) grow in MLSS Slow growing bacteria (nitrifiers) grow in the biofilm on the media since not enough SRT in MLSS HYBAS APPLICATION Upgrading carbon removal AS to nitrification or total nitrogen removal without any tank expansion Adding carriers for nitrification in a fraction of the existing AS reactor

23 Marquette-les-Lille WwTW, France Challenges: o Increasing population o Strict nitrogen demands o Relatively limited space available

24 Lille WwTW Upgrade of an AS plant into Europe s largest HYBAS Processes evaluated: AS: Too large SBR: Preference for continuous operation Pure MBBR: most compact but higher CAPEX (carriers for COD removal, nitrification, denitrification) Membranes: high CAPEX and complex operation Biostyr: high chemical consumption for TSS separation HYBAS! More compact than AS (55,000 m3) Fit in the available volume Lower sludge age higher biogas efficiency in anaerobic digestion Biological P removal as in AS Less carriers than pure MBBR (7,600 m3 of Chip M) Only nitrification on carriers Chemical free TSS separation unlike pure MBBR and Biostyr Robust facing peak loads and toxicity Nitrifiers in the biofilm more protected than in floc 24

25 Lille WwTW Upgrade of an AS plant into Europe s largest HYBAS 3 identical trains: PreAnox Denitr. NO3-N RAS PreDN Denitr NO3-N REC Hybas ChipM carriers nitrification PostNit NH4-N Polishing AS Anaero Promote Biolog P removal FeCl3 Methanol Tertiary Hydrotech filters Secondary clarifiers ReOx Remove remaining COD Strip N2 (g) bubbles Chemical P co-precipitation PostDN NO3-N Polishing AS 25

26 Lille WwTW Upgrade of an AS plant into Europe s largest HYBAS Design Parameters Design data - Inlet to the Hybas (after Multiflo and with reject water) Unit Average flow 246,342 m3/d BOD5 91 mg/l COD 231 mg/l TSS 114 mg/l TKN 35 mg/l TP 5 mg/l Objectives today: Parameter Concentration BOD5 20 mg/l COD 90 mg/l TSS 30 mg/l TKN 5 mg/l TN 10 mg/l TP 1.0 mg/l Objectives in 2027: Parameter Concentration BOD5 6 mg/l COD 70 mg/l TSS 10 mg/l TKN 2 mg/l TN 10 mg/l TP 0.7 mg/l Results year 2012: Moyenne Month Flow outlet WWTP Monthly averages Average conc outlet of the biological treatment (mg/l) TSS BOD5 COD TKN N-NH4 N-NO2 N-NO3 TN Pt JANVIER 160, FERVRIER 162, MARS 148, AVRIL 144, MAI 120, JUIN 108, JUILLET 97, AOUT 101, SEPTEMBRE 116, OCTOBRE 106,914 Already reaching limits NOVEMBRE 141, DECEMBRE 133, AVERAGE Reaching current limits and almost there with 2027 limits Higher DO in HYBAS to lower the NH4-N Boost P chemical co-precipitation 26

27 Different Configurations MBBR as sole biotreatment MBBR as pre-treatment MBBR as post-treatment MBBR in activated sludge (HYBAS/IFAS) Liquor Treatment - ANITAMox

28 Conventional Nitrification- Denitrification vs Anammox NH % 45% AOB Aerobic O 2 (40%) NO 2 - NH 4 + NOB NO - 3 O 2 Heterotrops COD Anammox COD (0%) NO 2 - N 2 + NO 3-89% 11% Anoxic -60% O 2-100% COD Big Savings

29 Properties of Anammox bacteria & AOB/NOBs - Grow in anoxic conditions (oxygen-free) - Very slow growing bacteria (slower than nitrifiers) Need very high SRT - High temperature ideal - Biofilm on the carriers optimum No washout - Biofarm concept to accelerate the start up 10% of the carriers are already seeded with Anammox Reduce start up from 18 months down to 2-3 months Reject water from anaerobic digestion : Low COD/TKN ratio High Temperature Research going on for mainstream water Soon full scale demonstration 29

30 Five Fords WwTW, ANITA Mox

31 Five Fords WwTW Flexible & robust liquor treatment Five Fords WwTP (Wales), PE Problem: Increase amount of the sludge to treat within the anaerobic digestion Implementation of Thermal Hydrolysis within the anaerobic digestion Higher nitrogen release (2,000 mg/l TKN) N out from the sludge treatment unit 25% of the N in the mainstream plant Need to treat this in a sidestream process Requirements from the client - Able to remove up to 85% of ammonia - Robust (THP generates toxics - Compact (optimised CAPEX) - Competitive OPEX 31

32 Five Fords WwTW Flexible & robust liquor treatment SOLUTION: HYBAS ANITAMOX Reactor volume: 927 m3 Media volume: 410 m3 of K5 Considerations to take for THP water: Dilution water needed Dilute the high N and toxic organic compound concentrations 1.4 treated effluent / 1 THP reject water Buffer tank upstream the HYBAS Anitamox Sludge centrifuges do not operate 24/7 Current status: Civil construction done Commissioning start-up Q

33 Q & A Bruno Bigot Chief Technical Officer, Northern Europe bruno.bigot@veolia.com William Jeal Sales Manager william.jeal@veolia.com