Experts in Chem-Feed and Water Treatment Desalination by membrane technology – state of the art and future trends Dr. Matthias Rothe and Oliver Hentschel ProMinent GmbH Im Schuhmachergewann 5-11, D Heidelberg Tel. +49 (6221) 842-0, Fax. +49 (6221)

Experts in Chem-Feed and Water Treatment Content Dr. Rothe, Oliver Hentschel, , SANEPAR 2 1.Basics and state of the art membrane filtration 2.Applications for desalination by membranes 3.Future trends for membrane desalination

Experts in Chem-Feed and Water Treatment 1. Basics and state of the art membrane filtration Dr. Rothe, Oliver Hentschel, , SANEPAR 3  Membrane filtration: removal of particles and salts ensuring lowest operating costs  physical process using semi-permeable membranes  4 technologies depending on the size of the particles/molecules to be removed  Microfiltration  Ultrafiltration  Nanofiltration  Reverse Osmosis

Experts in Chem-Feed and Water Treatment The Filtration Spectrum Dr. Rothe, Oliver Hentschel, , SANEPAR 4

Experts in Chem-Feed and Water Treatment Nanofiltration and Reverse Osmosis Dr. Rothe, Oliver Hentschel, , SANEPAR 5 Nanofiltration and Reverse Osmosis are the only membrane technologies to remove ions/salts from water ! How does it work ?

Experts in Chem-Feed and Water Treatment Osmosis diluted solution concentrated solution semipermeable membrane water column corresponding to osmotic pressure Dr. Rothe, Oliver Hentschel, , SANEPAR 6

Experts in Chem-Feed and Water Treatment Osmotic pressure π Dr. Rothe, Oliver Hentschel, , SANEPAR 7 Approx (mg/l) of TDS cause an osmotic pressure of (bar) depending on radius, valency and structure of ions Different salts cause different osmotic pressures. In reality there is always a mixture of these salts.

Experts in Chem-Feed and Water Treatment Reverse Osmosis Dr. Rothe, Oliver Hentschel, , SANEPAR 8 pressure diluted solution concentrated solution semipermeable membrane

Experts in Chem-Feed and Water Treatment Development of Reverse Osmosis Membranes Dr. Rothe, Oliver Hentschel, , SANEPAR9  cellulose acetate membranes  lifetime about 6 months  pH range:  salt rejection: up to 90-95%  polyamide hollow fibre modules  lifetime about 5 years  pH range:  salt rejection: up to 96-98%  less sensitive against bacteria  thin film composite membrane  lifetime about 10 years  pH range: 2 – 11, for cleaning:  salt rejection: up to 99.8%  stability up to 45°C  sanitary membr. 90°C  less sensitive against bacteria/biofilm

Experts in Chem-Feed and Water Treatment Thin film composite membrane Dr. Rothe, Oliver Hentschel, , SANEPAR10 Polyamide ultrathin barrier layer (approx µm) Polysulfone micro- porous support (approx. 40µm) Polyester non-woven web Carrier (approx. 120µm)

Experts in Chem-Feed and Water Treatment Crossflow membrane filtration Dr. Rothe, Oliver Hentschel, , SANEPAR11

Experts in Chem-Feed and Water Treatment Structure of thin film composite membrane module Dr. Rothe, Oliver Hentschel, , SANEPAR12 membraneglue perforation permeate pipe internal spacer

Experts in Chem-Feed and Water Treatment Structure of thin film composite membrane module Dr. Rothe, Oliver Hentschel, , SANEPAR13 internal spacer membrane external spacer permeate pipe membrane Element cover perforation internal spacer

Experts in Chem-Feed and Water Treatment Thin film composite membrane module Dr. Rothe, Oliver Hentschel, , SANEPAR14 ZWmh_Mw&feature=player_embedded

Experts in Chem-Feed and Water Treatment Water temperature influence on reverse osmosis Dr. Rothe, Oliver Hentschel, , SANEPAR15  increased water temperature  reduction of water viscosity  increased permeate production  but: decreased salt rejection

Experts in Chem-Feed and Water Treatment Operation pressure influence on reverse osmosis Dr. Rothe, Oliver Hentschel, , SANEPAR16 The salt rejection will be better, also The higher the pressure the more permeate flow is produced

Experts in Chem-Feed and Water Treatment Recovery of membrane systems Dr. Rothe, Oliver Hentschel, , SANEPAR17 R K P 25% drain to waste 75% permeate100% raw water Recovery [%]= Output : Input = (Permeate flow / raw water flow) x 100 Typical recoveries:70-80% for desalination of tap water 35-45% for desalination of sea water

Experts in Chem-Feed and Water Treatment Membrane systems, concentration factor Dr. Rothe, Oliver Hentschel, , SANEPAR18 Example: Recovery = 75 % = 0,75 CF = 1:1-0,75 = 1:0,25 = 4 i.e. there will be a 4-fold salt concentration in the reverse osmosis concentrate so a 4-fold osmotic pressure CF = Recovery

Experts in Chem-Feed and Water Treatment Membrane systems, salt passage/salt rejection Dr. Rothe, Oliver Hentschel, , SANEPAR19 Salt passage (%) = Permeate salt concentration x 100 Feed salt concentration Salt rejection (%) = 100 – Salt passage Examples for salt rejections of membranes of 99% and better: NaF NaCl CaCl2 MgSO4

Experts in Chem-Feed and Water Treatment Salt passage is affected by Dr. Rothe, Oliver Hentschel, , SANEPAR20 Increasing pressure (less passage) as well as increasing water temperature (higher passage, because of higher diffusion). The typical salt passage of an RO-system is % depending on membrane type and RO-design. Both dependencies are restricted to a certain pressure and temperature and have no linear functions.However, the effect of high pressure is stronger than that of higher temperature.

Experts in Chem-Feed and Water Treatment Typical reverse osmosis system Dr. Rothe, Oliver Hentschel, , SANEPAR / particle filter 2. pressure gauge 3. solenoid valve incl. check valve 4. pressure switch 5. thermometer 6. high-pressure pump 7. pressure vessel 8. membrane 9. conductivity probe 10. controller incl. conductivity measurement 11. flow meter permeate way valve 13. ball valve 14. flow meter concentrate way valve 16. flow meter concentrate recycle 17. sample valve 18. cleaning tank 19. cleaning pump 20. check valve

Experts in Chem-Feed and Water Treatment Typical reverse osmosis system Dr. Rothe, Oliver Hentschel, , SANEPAR pressure vessels incl. membranes 2switch cabinet with RO control unit 3cleaning tank 4flow meter permeate + concentrate 5particle filter 6 conductivity sensor permeate

Experts in Chem-Feed and Water Treatment Overall design of a membrane system Dr. Rothe, Oliver Hentschel, , SANEPAR23 Pre-treatment depending on the feed water‘s quality: filtration and chemical conditioning as a minimum Post-treatment depending on application

Experts in Chem-Feed and Water Treatment Applications for desalination by membranes Dr. Rothe, Oliver Hentschel, , SANEPAR24  Tap water desalination (typically up to mg/l of feed water salinity)  Brackish water desalination (typically – mg/l of feed water salinity)  Sea water desalination (typically more than mg/l of feed water salinity)

Experts in Chem-Feed and Water Treatment Desalination of tap water Dr. Rothe, Oliver Hentschel, , SANEPAR25 Reverse Osmosis permeate is used for:  Metal processing industry (rinse of metal parts)  Car washing companies (last rinse of the car is done by reverse osmosis permeate)  Food and beverage industry (rinse of salad/vegetables, rinse of chocolate forms, creation of a “standard” water for soft drinks like Coke)  Boiler and cooling water applications  Laboratories  Air condition systems  Cosmetic industry (shampoo production)  Car industry (e.g. water for paint shop)

Experts in Chem-Feed and Water Treatment Applications for Reverse Osmosis Dr. Rothe, Oliver Hentschel, , SANEPAR26  industrial water  desalination of tap water boiler water for steam production dilution water for juice- and softdrink production bottled water …  potable water production  desalination of brackish and sea water  reduction of nitrate  reduction of fluoride  reduction of arsenic

Experts in Chem-Feed and Water Treatment Desalination of tap water (installation example) Dr. Rothe, Oliver Hentschel, , SANEPAR27 3x tap water desalination m³/day, total m³/day, process water for paintshop of KIA motors

Experts in Chem-Feed and Water Treatment Desalination of tap water (installation example) Dr. Rothe, Oliver Hentschel, , SANEPAR28 3x tap water desalination m³/day, total m³/day, process water for paintshop of KIA motors

Experts in Chem-Feed and Water Treatment Desalination of brackish and sea water Dr. Rothe, Oliver Hentschel, , SANEPAR29 Production of potable water for human consumption and/or irrigation (e.g. for hotels, villages, etc.) Hotel „Le Paradis“ Mauritius

Experts in Chem-Feed and Water Treatment Desalination of sea water installation example Dr. Rothe, Oliver Hentschel, , SANEPAR30 2x sea water desalination 400 m³/day, total 800 m³/day for hotel „Le Paradis“ Mauritius

Experts in Chem-Feed and Water Treatment Desalination of sea water installation example Dr. Rothe, Oliver Hentschel, , SANEPAR31 2x sea water desalination 400 m³/day, total 800 m³/day for hotel „Le Paradis“ Mauritius

Experts in Chem-Feed and Water Treatment Future trends for membrane desalination Dr. Rothe, Oliver Hentschel, , SANEPAR32 nano-coating structures on the active membrane layer, advantages: a.anti-fouling properties are improved

Experts in Chem-Feed and Water Treatment Future trends for membrane desalination Dr. Rothe, Oliver Hentschel, , SANEPAR33 b.Increase in permeability less energy is needed at improved salt rejection rates first membranes with nano-coating are commercially available now

Experts in Chem-Feed and Water Treatment Future trends for membrane desalination Dr. Rothe, Oliver Hentschel, , SANEPAR34 decreased energy consumption membrane desalination with renewable energies like solar power …

Experts in Chem-Feed and Water Treatment Future trends for membrane desalination Dr. Rothe, Oliver Hentschel, , SANEPAR35 … or wind energy:

Experts in Chem-Feed and Water Treatment Future trends for membrane desalination Dr. Rothe, Oliver Hentschel, , SANEPAR36 Combination of membrane technologies, e.g. Micro- and Ultrafiltration (MF/UF) as pre-treatment followed by reverse osmosis, advantages: a.Smaller footprint of complete water treatment plant which leads to smaller buildings b.Better quality water of pre-treatment e.g. in comparison to classical sand filters c.Reverse osmosis after MF/UF can be designed much more aggressive because of higher filtrate quality. This saves investment and operation costs on the reverse osmosis downstream

Experts in Chem-Feed and Water Treatment Future trends for membrane desalination Dr. Rothe, Oliver Hentschel, , SANEPAR37 Energy recovery on sea water desalination systems has moved from turbines to pressure exchangers. They reduce energy consumption of a sea water desalination units by 50-60% !

Experts in Chem-Feed and Water Treatment Cost considerations Dr. Rothe, Oliver Hentschel, , SANEPAR38 Typical Pressure Typical Recovery Typical Energy Consumption for RO PW bar up to 80 %0,4 – 0,75 kWh/m³ BW barup to 60 %1,2 – 2,00 kWh/m³ SW without ER barup to %4 – 8 kWh/m³ SW with PX barup to %1,8 – 3,5 kWh/m³ Energy consumption depend on:  Salinity and permeate quality  Recovery Rate  Feed Water Temperature  Membrane Type and Aging (Fouling/Scaling)  Pump Type and Configuration

Experts in Chem-Feed and Water Treatment Energy consumption of large SWTP Dr. Rothe, Oliver Hentschel, , SANEPAR39 Source: Watereuse: Seawater desalination Power consumption

Experts in Chem-Feed and Water Treatment Typical Range of SWRO Facility Costs Dr. Rothe, Oliver Hentschel, , SANEPAR40 Source: Watereuse: Seawater desalination Power consumption

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