NSERC Chair in Water Treatment Membranes in Drinking Water Treatment Peter M. Huck Professor and NSERC Chairholder in Water Treatment University of Waterloo, Canada

Topics for discussion  Introduction  Goals and processes for treatment  Membrane fouling reduction

Orientation

NSERC Chair  Senior research professorship supported jointly by NSERC (Natural Sciences and Engineering Research Council of Canada), the University of Waterloo and ‘industrial’ partners (NSERC matches industrial cash and in-kind)  Part of Department of Civil and Environmental Engineering  Granted in five year terms  Support for students, staff, research costs  Centre of Expertise

Some 4 th Term Statistics ( )  Now in Year 18 of 20  Major themes – chemical and (micro)biological contaminants Source water and treatment  10 on-site students (6 Ph.D.), 2 off-site  Usually one post-doc  Technical and administrative professionals  Eighteen ‘industrial’ partners Municipal water works, consultants, etc.

NSERC Industrial Research Chair Partners

Current Major Areas of Research  Emerging microbial contaminants  Membranes  Evaluating point-of-use treatment  Trace chemical contaminants e.g pharmaceuticals and endocrine disruptors Adsorption, oxidation, membranes  Membranes – fouling  Biological pre-treatment to reduce fouling

Goals for treatment  Removal of particles (including pathogenic micro-organisms)  Removal of TOC (‘background’ organic matter) e.g. from leaves, soil, algae, wastewater  Disinfection/inactivation  Removal of chemical contaminants e.g. pesticides, pharmaceuticals, volatiles

Goals for treatment - 2  Biological stability Avoiding bacterial regrowth in distribution system  Chemical stability Corrosion, precipitation in distribution system  Maintaining aethetic quality to the consumer’s tap

Future trends in treatment  Reduction in chemical usage -> tends to favour membranes  Reduction in carbon footprint – ‘green’ technologies  Simple and secure treatment -> also tends to favour membranes

Some additional trends  Desalination – where feasible  Partial reuse -> dual systems (risk management)  Reduced consumption

Membranes

What’s a membrane?  Usually, a sheet of polymer with very fine holes  Push/pull the water through, keep out (most of the) contaminants ‘Rejection’ depends to a big extent on size of the holes (pores), the chemical composition of the membrane, characteristics and size of the contaminants and some operating factors (e.g. flowrate)

Membrane types  Microfiltration  Ultrafiltration  Nanofiltration  Reverse osmosis

Capabilities of membranes UF NF ROMF Particles, algae, protoz- oans, bacteria Macromolecules, viruses Multi- valent ions, TOC Monovalent ions (Na+, Cl-) Water molecules Pore sixe µm 1-100nm ~ 1nm <1nm

ZeeWeed ® Membranes (GE-Zenon) Module ZeeWeed ® - 500

Nanofiltration – spiral-wound modules

Ceramic membranes

Development of Alternative Membrane Integrity Detection Tools for Low Pressure Membranes Treating Filter Backwash Water M.E. Walsh 1, M.P. Chaulk 2 & G.A. Gagnon 1 1 Department of Civil Engineering, Dalhousie University 2 Zenon Environmental Inc. AWWA WQTC November 2005 Québec City, QC, Canada

Project Objectives Evaluate current integrity test methodologies for UF membrane treatment of WTP residual streams Particle counting & turbidity measurements Explore alternative indirect integrity test methods DOC and color Capability for detecting “precursor” signals to breaches in a membrane operating system (chronic increases in dissolved material (i.e., NOM)

Integrity Trials FBWW Creation of Challenge Conditions Extended run period without chemical cleaning Simulate initial stages of failure in membrane operating system Accelerated fouling rate Degradation of membrane fibers

Flux – a key parameter  Flow of water per unit membrane surface area and time (e.g. litres per square metre per hour – lmh)  CAPITAL COSTS

Fouling – the enemy of flux New membrane Membrane after fouling

Effect of fouling on flux

 Caused by particles, organics and other substances in incoming water  Extent of fouling determined by Concentration and type of incoming foulants Pre-treatment Membrane operating and cleaning conditions Fouling

Grand River drainage basin

Some biofiltration basics Biological processes Attachment Detachment Biodegradation Growth Decay Hozalski et al., Water Research, 2001

Process schematic for biofiltration pre-treatment for UF

Grand River 3 - DOC characterization* Building blocks *Liquid Chromatography-Organic Carbon Detection (TU Berlin) TOC/DOC about 6 mg/L

Impact on fouling

Impact on fouling - 2

Impact on fouling - 3 Hallé et al. ES&T, 2009

Pilot confirmation

Possible process train (Roughing filtration) → Biofiltration → UF → (Disinfection)

Membrane types  Microfiltration (MF)  Ultrafiltration (UF)  Nanofiltration (NF)  Reverse osmosis (RO)

Some membrane applications in Australia Source: Google Maps

Example of a two-stage system for water reuse – Perth, Australia

Perth - 2

Biofouling of high pressure membranes  In long term operation, biofouling (growth of biofilm on the membrane) a serious operational issue

Desalination in Adelaide

Pretreatment - 1

Pretreatment - 2

Hands-on testing

Possible process train (Roughing filtration) → Biofiltration → UF → RO → (Disinfection)

Some future work  Biofiltration and low pressure membranes Net removal of biopolymers Particulate removal  Biofiltration and high pressure membranes (desalination) Removal of easily biodegradable carbon (AOC) to very low levels  Biofiltration as membrane pre-treatment in water reuse

Concluding remarks  Challenging issues in drinking water treatment and provision  Membranes important  Rapid biofiltration (without coagulation) effective to reduce organic fouling of UF membranes Robust, simple, ‘green’ Potential for RO (biofouling), water reuse pre-treatment

Acknowledgments  NSERC, Canadian Water Network, GE, Region of Waterloo  NSERC Chair partners