NSERC Chair in Water Treatment Membranes in Drinking Water Treatment Peter M. Huck Professor and...
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Transcript of NSERC Chair in Water Treatment Membranes in Drinking Water Treatment Peter M. Huck Professor and...
NSERC Chair in Water Treatment
Membranes in Drinking Water Treatment
Peter M. HuckProfessor and NSERC Chairholder in
Water TreatmentUniversity 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 4th Term Statistics (2008-2012)
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
UFUF
NFNF
RROO
MMFF
Particles, algae, protoz-oans, bacteria
Macromolecules, viruses
Multi-valent ions,
TOC
Monovalent ions (Na+, Cl-)
Water molecules
Pore sixe
0.1 -1µm
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. Walsh1, M.P. Chaulk2 & G.A. Gagnon1
1Department of Civil Engineering, Dalhousie University 2Zenon Environmental Inc.
AWWA WQTCNovember 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
www.civil.uwaterloo.ca/watertreatment