Urban Water Systems – Pennine Water Group The University of Sheffield
Professor Simon Tait ([email protected])
Pennine Water Group
• EPSRC Platform Grant - Awarded in 2001 and renewed in 2005 and again in
2010
• Most established Urban Water Group in UK, unique with second renewal of
PG
• International Track Record
• 6 Professors and their research groups – Over 50 active researchers in
water
• The Pennine Water Group has developed a holistic and integrated approach to
improving the performance of urban water that spans disciplines and crosses
international and institutional boundaries.
• The range of disciplinary expertise includes; engineering, economics
microbiology, computer science and the social sciences.
• Projects funded by EPSRC/NERC/EU FR7/EU Marie Curie/EU Interreg/Water
Industry/Investors
• Recent investment by University in new staff and facilities
Prof. David Lerner
Catchment Science
Prof. Simon Tait
Sewers and Rivers
Prof. Kirill Horoshenkov
Sensors - Acoustics
Key Water Engineering Staff at Sheffield
Prof. Joby Boxall
Water Infrastructure
Prof. Catherine Biggs
Water Process Engineering
Prof. Adrian Saul
Urban Water Engineering
Dr Songdong Shao, Particle Based Modelling, Dr Chris Keylock,
Turbulence; Dr Wernher Brevis, Shallow Flows, Dr James
Shucksmith, River Pollutant Processes; Dr Liz Sharp Social Science
- Governance, Dr Virginia Stovin, Green Infrastructure, Professor
Richard Ashley – Water Sensitive Urban Design, Dr Richard Collins
– Potable Water Systems, Dr Henriette Jensen – Biofilms, Dr
George Kesserwani – Flood Modelling/ Flash Floods, Prof Will
Zimmerman – Treatment Processes
Pennine Water Group
Research Strategy
PWG - Work Areas
Three work areas – multi-disciplinary projects
• Sustainable Integrated Systems
• New Technologies - Urban Water Engineering
• Engagement and Implementation
Sustainable Integrated Systems
Deliver tools, techniques and models which capture and
explain the complex interaction between the urban and rural
environment at a range of scales
• Automated Data Analysis - soft
computing approaches for
turning data into information
• Optimal instrumentation
location and development
• Transients for leak detection
• Dynamic behaviour of leakage
• Fixing the DRIP (data rich
information poor)
• Fuzzy diagnostics for event
detection and identification
(quantity and quality)
• Local vs. central intelligence
Leakage
PODDS: Prediction and control of Discolouration in Distribution Systems
Water Engineering ResearchUniversity of Sheffield
Department of Civil & Structural Engineeringwww.PODDS.co.uk
Water Distribution System Flushing Strategies:
Current Research ImplicationsThe PODDS approach to Water Distribution System (WDS) management is based on scientific research that has shown discolouration is a predictable response to increases in system shear stress. Applying an hydraulic shear force(τa) above the peak daily (τ’) creates an excess shear (τexcess) leading to discolouration (see figure 1). The response is a function of the strength characteristics and discolouration potential (C) of material layers attached to the pipe walls.
Material layers develop throughout the WDS with asset deterioration primarily being determined by water quality (amount of material entrained) and conditioning hydraulics. Optimal pro-active management strategies are required to maintain assets yet minimise network interventions, thus saving time, money and limit discolouration risk to customers. To achieve this pipe material needs to be considered during operational planning as material accumulation processes, layer strength characteristics and discolouration potential are different in plastic and cast iron pipes
Plastic
or smooth-walled pipes
Cast Iron
or rough-walled pipes
Figure 1 – PODDS model of layer shear strength vs. discolouration potential
1Average UK value; actual deterioration rate variable based on water quality and network hydraulics.Warning: potential discolouration risk can be posed much sooner.
2Value shown based on work in the Netherlands by KIWA.
Dr. Joby Boxall Tel: 0114 2225760
email: [email protected]
Mr. Stewart Husband Tel: 0114 2225416
email: [email protected]
August 2007
Modelling has shown that a flushing induced force of 1.2 N/m2 is sufficient to
mobilise all material layers and clean pipe. MAINTENANCE
Modelling has shown that for any increase in applied shear force (e.g. flushing), material will continue to be mobilised.
"6/11
"4/5
"3/3
/6.0/2.1 2
sl
sl
sl
smmN TARGET
FLUSHING VELOCITY
Risk based value. Criteria: available flow, pipe discolouration
status and risk of unplanned hydraulic disequilibria.
4 Years
1DETERIORATION (from clean to maximum risk)
1.5 years surface water 3 years ground water
a) Research suggests a peak daily flow of 20.4m/s will promote “self-cleaning” b) Improving water quality (reduces
deterioration rate).
OPERATION
a) Higher daily flows reduce potential discolouration event magnitude.
b) Improving water quality (reduces deterioration rate).
Biofilms believed integral to cohesive layers formation; liable to ‘slough’ increasing
discolouration risk.
NOTES Corrosion by-products increase pipe
deterioration rate and ‘feed’ downstream pipes (irrespective of material).
Implementation of self-cleaning velocity criteria to maintain residential water quality (networks characterised by a branched structure with
downstream declining diameter)
NETWORK DESIGN
Not applicable
∞
∞
?
Layer Shear strength , τ (N/m2)
1.2
Dis
colo
ura
tio
n p
ote
nti
al
C (
NT
Um
)
τ’ τa
τexcess
Cplastic
Ciron
CI pipe
Plastic pipe∞
∞
?
Layer Shear strength , τ (N/m2)
1.2
Dis
colo
ura
tio
n p
ote
nti
al
C (
NT
Um
)
τ’ τa
τexcess
Cplastic
Ciron
CI pipe
Plastic pipe
Discolouration - Quantifying discolouration
impact of flow changes
- Maintain TM flexibility by
conditioning procedures
(maintenance schedules
with no water loss)
- Simulate discoloured water
event potential
Radar and rainfall forecasting – sewer network modelling
Overall, using radar or rain gauge gives similar flow simulation results, but flow peaks can be considerably different in intensity and/or timing
Differences in return periods within small area
Current rainfall measurements and hydrodynamic sewer flow model Both not accurate enough for flood prediction on individual street level
Date07/07/2008 Time13:40
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Ilkley Date07/07/2008 Time13:40
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RG4
RG5RG3
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• Case study flooding associated with sewer
sediment deposits
• Quantify uncertainty in sewer sediment transport
modelling
• Laboratory measurement of physical sewer
sediment properties + models
Systems Modelling Uncertainty
5 ‘surfaces’, one for
each different
roughness
Uncertainty in Ackers-White sediment transport equations - Ggr ratio Uncertainty due to variability input parameters (ks and d35) Predicted deposit levels - multi month rainfall time series, for sensible ranges of Ggr ratio, ks and d35 Response surface created Monte Carlo Sampling
Overall Uncertainty – Response Surface
Baseline
no of
failures
Range of failures due
to uncertainty
Water Quality Failures – Integrated Models - Uncertainty
• Focussed on diatoms
• Lab experiments on effects of
detergents and nutrients
• Field measurements of upstream to
downstream changes
• Planned:
• Field measurements of before
and after rectification
Research on ecological impacts of misconnections
Sustainable Integrated Systems
• Leakage modelling and monitoring
• Potable water quality management
• Integrated catchment modelling
• Water sensitive urban design
• Urban Rivers and Flooding – Resilience and Recovery
• 2D Flood modelling – drainage /surface interactions
• Whole life costing of urban drainage systems
• System adaptation to climate change
• Heat recovery in urban water systems
Development and Delivery of New Technologies
• To monitor, control and maximise the performance of our existing, deteriorating urban water infrastructure, and how it integrates within the wider water system.
• Three sub-themes have been identified:
bio-engineering
low-cost, adaptive sensor networks
communication, data analysis and interpretation
Development and Delivery of New Technologies
• Synthetic biology in the water industry
• Cell to cell interactions
• Micro bubble created using fluidic oscillation
• Sensor technologies – sewer and potable water systems
• Biofilm and bacteria in potable water distribution networks
• DNA based classification of in-sewer bacterial communities
Microbiology in Water Systems
• Distribution system as reactors,
not inert network of pipes
• Vast surface area, high residence times,
uncertain and variable conditions
• Physically, chemically and biologically
complex and active systems
Pipe Dreams
Internationally unique facilities
• DNA based typing of in-sewer bacterial
communities
• Seasonal and spatial effects; overflow
performance and corrosion
• Odour processes and modelling
Sewer System Characterisation
Anaerobic digesters: Micro bubbles go
where no bubble has gone before
Methanogensis:
AD does not require a gaseous nutrient, so micro bubbles of what
carrier gas?
High purity CO2 as a carrier gas produces 100% more biogas
Reduces CO2 emissions by bacteria fixing it to hydrogen, producing
methane fuel which can be recycled on the plant by producing
electricity and heat, put to the gas mains, or
Underpins EPSRC 4CU Programme Grant (£4.6m) for use as a high
energy chemical feedstock
Instrumentation – Development
• Mainly acoustic based – low power and robust –
scattering or reflection principles
• Condition monitoring – cracks/defects/blockages in
pipes – “Sewerbatt” – reflectometry – Acoustic Sensing
Technology Ltd
• Acoustic scattering devices – non-contact flow
monitoring – very accurate water depth, flow velocities
hydraulic resistance – acoustic scattering from water
surface waves
Wave probe Ultrasonics
Water surface Flow
PIV/LIF
Flow velocity/surface waves/acoustics
Still
D = 60mm D = 90mm
Experimental set-up
0 50 100 150 200-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
Spatial lag (mm)
Corr
ela
tion c
oeff
icie
nt
(-)
Temporal cross-correlation of non-equidistant wave probes
0mm sep
30mm sep
50mm sep
70mm sep
80mm sep
90mm sep
110mm sep
120mm sep
114 115 116 117 118 119 120 121 122 123 124
73
74
75
Depth
(m
m)
Time (s)
Time series from two wave probes seperated by 30mm
0 100 200 300 400 500-1
-0.5
0
0.5
1
Corr
ela
tion c
oeff
icie
nt
(-)
Probe separation (mm)
Spatial surface correlation function
- Wave gauge analysis
Surface wave analysis
Test Depth
(mm)
Flow rate
(l/s)
Mean Vel
(m/s)
Surface Vel
(m/s)
Corrected
Acoustic
Vel
(m/s)
Error
(%)
1 53 3.1 0.38 0.49 0.39 1.8
2 72 6.7 0.52 0.67 0.49 6.5
3 98 11.1 0.56 0.75 0.58 2.9
Field Prototype Devices – river and sewer pipes
• Significant uncertainty
• Magnitude
• Frequency
• Duration
• Structural impacts
• Catastrophic failure
• Long term fatigue loading?
• Water quality impacts
• Ingress
• Mobilisation of material layers,
including biofilms and
pathogens?
Occurrence and impacts of transients
Engagement and Implementation
• To change the values associated
with water, especially in association with the new energy and carbon agendas
• Economics/Governance/public engagement/planning
• Three sub-themes have been identified:
Engagement and governance
Novel technologies
Collaboration and translation
Engagement and Implementation
• Prepared – institutional adaptation to climate change
• Public participation activities
• Acoustic Sensing Technology Ltd – acoustic condition sensors
• Novel sensors to detect leakage
• Real time monitoring and control of water systems
Large EU funded
integrated project
35 partners – utilities
(water companies) and
research institutes
4 year project –
research and
application
PWG involvement -
institutional adaptation
Water Utility Partner -
DCWW
PREPARED: Cities, water & climate change adaptation
PREPARED: Cities, water & climate change adaptation
Engineering researchers
Social scientists
Welsh water practitioners
PREPARED requirement:
research AND
implementation.
Aim: ‘To help water
management become
more adaptive in Wales’
Framework
• Interviews
• Documentary analysis
Audit Tool
• Workshops
• Scenarios
Action Plan
• Evaluate action
Adaption Planning Process
Manual
Acoustic Inspection of Sewer Defects
• Acoustic – airborne monitoring –
combined sewers
• Multi frequency signal – reflection
pattern identifies defect
• Fast – no man entry
• Practicality of widespread inspection
– better asset management
Condition Defects
by CCTV
Defects* by
Acoustic Method
Acoustic vs. CCTV
(%)
Acoustic distance RMS
Difference (m)
Next manhole 24 20 83 0.21
Lateral connection 95 86 75 0.48
Crack (all types) 69 57 71 0.42
Joint - displaced 22 16 55 0.27
Total 210 179 71 0.35
• An acoustic method of condition
detection is an fast alternative to
CCTV.
• This method can detect standard
conditions such as lateral
connections, blockages, cracks and
their combinations.
• Acoustic signatures can be recorded
and stored in a database for
automatic condition detection and
recognition.
• Low power and data storage
requirements
• Equipment now commercially
available
Acoustic Inspection of Sewer Defects
• Forecasting environmental
conditions in order that the waste
water treatment works can be
controlled
• Offers reduction in energy cost /
improved water quality
Real Time Control of Treatment
Facilities – Urban Water Systems
1D Flumes + annular flume + flooding rigs
PIV/ADV/LSPIV
High speed imaging
Water quality measurement
DNA based techniques
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Monitoring time steps (5 mins interval)
Ch
am
be
r w
ate
r le
ve
l (m
m)
Model prediction output sample from Carleton Rd Skepton CSO
Prediected value
Actaully value
Chamber weir height
Chamber weir
Prediction model output sample
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Wider Engagement at Sheffield
Conclusions
• Large, well resourced multi-disciplinary group
• Broad, well integrated water R&D across
different disciplines
• Three work themes: sustainable integrated
systems, new technologies, implementation and
engagement
• Strong alignment with UK Government and EU
Strategic Priorities
• Unique facilities and able to call on a large
science base (physical and social sciences)