Chapter 16. Membrane Bioreactor (MBR)

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1 Chapter 16. Membrane Bioreactor (MBR)

2 Global warming -The numerous scientists agree reality of global warming: Glaciers are melting, plants and animals are being forced from their habitat, and the number of severe storms and droughts is increasing. Source: USEPA

3 Global Water Shortage in 2025 Very high stress High stress Mid stress No stress No data Source : International water management institute - Water shortage population: 1.1 billions in 2005 and 3 billions in WHO reports that 3.4 million per year were killed by waterborne diseases in 2005

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7 국내외환경시장동향 패러다임의변화 : 공해방지사업 경제적재화창출산업 물산업의성장 : Black gold (20 세기 ) Blue gold (21 세기 )

8 The life cycle of water quality Agricultural : 74% Municipal : 14% Industrial : 12% (Global market 2005~2015,IDA report) : Core business segment Usage f Water Quality o Source Desalination Water Treatment Surface / Ground water : 3% Seawater : 97% Wastewater Advanced WWT Reuse Treatment Conventional WWT* Water Reuse Effluent Time Sequence - Two of the most sustainable ways to create alternative water source: 1) Advanced wastewater treatment and reuse MBR Process 2) Seawater desalination RO Process - Key for these treatment processes: Membrane Technology *Courtesy of Doosan heavy Industries and construction Co.

9 Growth of MBR Market CAGR, Compound Annual Growth Rate

10 Membrane Market for Water Treatment Water treatment 160 M$ 330 M$ (2010) (2016) Wastewater treatmen 460 M$ 900 M$ (2010) (2016) 분리막 Membrane Seawater Desalination Water Reuse 450 M$ 800 M$ 120 M$ 390 M$ (2010) (2016) (2010) (2016) 10 시장규모 : 100~200 % 증가 (2010~2016) 차세대성장동력산업기술로서

11 Wastewater Reclamation & Reuse Plants Wastewater MF RO Disinfections Reclamation Reuse Country Location Capacity Operation Plant Membrane (m3/d) Year Supplier Supplier 1 Kuwait Sulaibiya libi 300, IONICS Toray 2 USA CA Fountain Val 264, PROJECT 3 Singapore Ulu Pandan 140, India Chennai 135, CAMP DRESSER 5 USA CA San Diego 75,000 6 Spain Almeria 42, PRIDESA/INIMA PERMETEC ES 7 Singapore Kranji 40, VEOLIA Hydranautics 8 Singapore Bedok 32, HYFLUX Hydranautics 9 Saudi Arabia Jeddah 30, BIWATER GB DuPont 10 Korea 26, IONICS US Dow/Filmtec 11 Singapore Seletar 24, HYFLUX Toray 12 Japan 22, KURITA JP Toray 13 USA AZ Scottsdale 22, ADVANCED ES USA Koch (Nov :Based on IDA Inventory Report 2002) Toray less-fouling RO was selected at the world s largest RO plant

12 Needs for Advanced Treatment & Processes Why do we Need Advanced Treatment & Processes? Although water resources are fixed, 1. The quality of available water resources steadily declines 2. New technology to detect contaminants developes 3. Environmental standards become more and more tight 4. Wastewater reuse becomes more and more important in line with climate change

13 Driving forces for membrane separation Phase 1 Membrane Phase 2 Feed Permeate Driving force Driving force ( C, P, T, E)

14 Pressure driven membrane separation processes

15 Membrane and Relative Size of Common Materials Ultrafiltration Microfiltration MF Nanofiltration UF Membrane Reverse Osmosis NF RO Size (μ m) Relative Size of Common Materials Application Cl - ion Na + ion Pesticide, Organic Material Influenza Virus Algae, Mad Zn 2+ ion Vibrio Cholerae F - ion Virus Pb 2+ ion Polio Virus Coliform Cryptosporidium NO - 3 ion Trihalomethane Hepatitis A Virus Bacillus anthracis Sea Water Desalination Brackish Water Desalination Drinking Water Wastewater Treatment Wastewater Treatment Drinking Water Drinking Water Toray

16 Separation Characteristics of Various Membranes RO/NF Membranes UF/MF Membranes Permeatio n and rejection Low MW organic ma Middle to high h MW terials materials (Mw 200) (Mw >200) Monovalent ions Water Multivalent ions Membrane Water Ions Dissolved matter Suspended Solid Particles Membrane Separation mechanism Pore siz e RO: Molecular interaction MF: Dynamic separation Solution diffusion Electric repulsion Size exclusion NF: Size exclusion UF: Electric repulsion RO: <1 nm UF: 10~100 nm NF: 1~10 nm MF: >100 nm Toray

17 Role of Membrane Technology in Water Environment 수자원부족 수질악화 환경규제강화 혼성시스템 막분리공정을이용한고도수처리기술 (Membrane Process for Water and Wastewater Treatment and Reuse - MF, UF, NF, RO, ED,...) 생물학적처리, 흡착, 응집, 화학침전, 고급산화, 광촉매, 이온교환 21 세기 : 새로운혼성시스템개발, 새로운막모듈개발, 막오염제어기술의혁신등 양질의음용수및공업용수생산 Water Mining: 중수생산및재이용 청정기술 : 폐수재이용 / 유가자원회수, 무방류시스템

18 Application of Membrane Processes in Water Environment 융합기술 수질공학분자생물학계면화학 나노입자 / 나노세공 난배양성미샘물모니터링바이오필름미시유체역학균일상촉매 우주정거장 항공기 빌딩 / 사무실 위락시설 가정 / 주택 공장 / 공단 생태용수 지하수

19 CAS vs. MBR - Conventional Activated t Sludge (CAS) Influent Activated Sludge Reactor Sedimentation Tank Effluent Returned Sludge Wasted Sludge - Membrane Bioreactor (MBR) Activated Sludge Reactor Membrane Unit Influent Permeate(Effluent) Retentate

20 Characteristics of MBR 1) Microbial flocs are completely rejected by a membrane so that bacteria which would carry over from the settling tank in CAS are retained in the reactor. selection of bacteria is no more based on settleability sludge bulking is no more problem. settleability of the sludge is no more an important design parameter 2) It is possible to increase the biomass concentration up to 20 or 30 g/l 3 and to strongly mix the aeration tank with eventual breakage of the flocs (Pinpoint floc).

21 Characteristics of MBR 3) As a consequence of retaining high biomass concentration, the substrate utilization rate increases thus allowing more compact equipment ( smaller hydraulic residence time ) 4) Higher biomass concentration means longer sludge age (SRT) with beneficial effects on the efficiency and on net sludge production. θ χ activebiomassin the system = = μ production rate of activebiomass 1 [ 3.22 ] θ x = X a V e e Q X + Q a w X w a [5.35] 1 dx a S μ = = μsyn + μdec = μ X dt K a + S -b [3.5]

22 Characteristics of MBR 5) MBR operation under side stream mode generally needs high shear stress resulting in floc breakage (Pinpoint floc) and production of microflocs which make more efficient the oxygen and substrate transfer. 6) The small particles and the colloids less easily degradable than solutes are rejected by the membrane and stay in the aeration tank until they are in good conditions for being degraded 7) The quality of the treated water is not only due directly to ) q y y y the membrane but also indirectly to the different and more efficient conditions in the bioreactor.

23 Characteristics of MBR 8) The biological i l reactor may be considered d as a Continuous Stirred Tank Reactor (CSTR ). 9) The membrane is continuously in contact with a suspension containing two fractions : i) the microflocs ( size 10 to 100 μm ) ii) the interstitial liquid which quality is almost that of the biologically treated water The physicochemical interactions between membrane and broth constituents give rise to membrane fouling.

24 Advantages of MBR 1) Small Hydraulic Residence Time (HRT) Compactness of Reactor 2) Large Sludge Residence Time (SRT) High concentration of microorganisms High efficiency of BOD removal small excess sludge production enhancement of slow growing bacteria Almost complete nitrification 3) Complete rejection of microbial flocs and colloids High quality of treated water Effluent of very low turbidity highly effective disinfection

25 Sludge production for various wastewater treatment processes Treatment process Sludge production (kg/kgbod -1 ) Submerged MBR 0.0~0.3 Structured media BAF 0.15~0.25 Trickling filter 0.3~0.5 Conventional activated sludge 0.6 Granular media BAF 0.63~ * BAF ; biological activated filter T. Stephenson

26 Disadvantage of MBR 1) Higher energy consumption than CAS (conventional activated sludge). 2) Membrane Fouling which gives rise to flux decrease 2) Membrane Fouling which gives rise to flux decrease and eventually membrane replacement.

27 Comparison of energy consumption between cross-flow and submerged MBR Process Conventional Activated sludge Average power consumption (kwh/m 3 ) T. Ueda P. Cote Cross-flow MBR Submerged MBR

28 Comparison between the power costs of MBR and conventional activated sludge Maximum Throughput / Average Throughput MBR Activated Sludge 1,400 / 650 m 3 /day 10,000 / year 13,000 / year 22,500 / 10,500 m 3 /day 106,917 / year 148,070 / year

29 MBR operation mode ( Side Stream vs. Submerged ) Side stream (Crossflow) MBR Submerged (dead-end)mbr

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31 Types of MBR a) Traditional wastewater treatment ( 전통적인생물학적처리공정 ) b) External crossflow and side stream ( 외부십자흐름분리형 ) c) Internal submerged ( 내부침지형 ) d) External submerged ( 분리침지형 )

32 Membrane modules for MBR Hollow fiber Plate Tubular MF MF UF Out-In Out-In In-Out Submerged Crossflow/ Submerged Crossflow

33 Membrane Modules for MBR Plate & Frame type

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35 Membrane modules for MBR Hollow fiber type

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37 Membrane modules for MBR Tubular type Ceramic membrane

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42 MBR Providers in North America USFilter 10% Others 3% Koch 2% Kubota 20% GE-Zenon 65% NA Market Share, Revenue Graeme Pearce, 2008