Embed Size (px)
DESCRIPTION
Citation preview
Upgrading the longest
running microfiltration plant
in the UK
Peter Hillis, Water Treatment Technical Expert, UU
Engineering
1
Outline
Background and History
Drivers for Change
Pilot Trials
Comparison Pilot vs. Full-Scale
Outcome
2
Background and History
Lake District, NW England
59 Ml/d (15 MGD)
Cryptosporidium
Commissioned in late 1999
Longest running MF plant in
UK
This is a single source supply
– no alternatives
3
Current Process Flow Diagram
Contact Tank
59 Ml/d
PACl
Clarifier
Tanker
2% Sludge
2 x 90M10C
Secondary Microfiltration
Primary Microfiltration
17 x 90M10CPre-screen
4
Intake at Ennerdale Lake
5
Ennerdale WTW
6
Ennerdale WTW
7
Primary Membrane Operation
Backwash Interval – 60 minutes
Backwash Duration – 2.5 minutes
Monthly caustic clean (1.25%)
Six monthly Peroxide clean
Sulphuric acid clean as required (pH2)
Zero Discharge Site – no sewer or discharge to the Lake
8
Secondary Membrane Operation
Feed to secondary units is blend of
• primary backwash water (20 mg/l )
• clarifier decant (5 - 25 NTU)
Clarifier is fed from blend of
• secondary backwash water (100 - 200 mg/l)
• neutralized CIP solution
Lake water low in dissolved solids (50 µS/cm)
• coagulation sensitive to neutral CIP waste
Clarifier sludge 2%, 18 m³/day
• most difficult area, problems can shut plant
9
Drivers for Change
Plant has operated successfully for over 10 years
Membrane life of PP >10 Years
Why change from something that works well?
Improved efficiency – power, chemicals, waste
Improved flexibility – operation
Improved waste treatment
10
Historic Performance TMP and Flow
11
Historic Performance Membrane Resistance
12
Feed water quality 2000 to 2009
TOC (mg/l) Turbidity (NTU) Iron (ug/l)Manganese
(ug/l)
Aluminium
(ug/l)
Average 1.09 0.68 26.61 6.67 38.57
Max 4.22 3.99 166 39 245
Min 0.25 0.12 5 2 14.24
Std Dev 0.48 0.48 18.25 5.26 22.89
No 241 171 171 191 171
13
Pilot Trials – Main Plant Comparison
Pilot Plant
PVdF Membrane
Siemens Memcor L10V
23m2 membrane area per module
Flux 73 lmh
Backwash Interval – 60 minutes
Backwash Volume – 17 l/module
Backwash Duration – 2.5 mins
Main Plant
PP Membrane
Siemens Memcor M10C
28m2 membrane area per module
Design Flux 41 lmh
Backwash Interval – 60 minutes
Backwash Volume – 55 l/module
Backwash Duration – 1.5 mins
14
Pilot Plant Results
120565.001.40110244710/9/079
120566.401.5311024435/7/078
60563.351.466027341/6/077
60565.281.2497276627/3/076
60562.651.2158303520/2/075
60733.431.23103343016/1/074
60735.231.2314933396/12/063
60734.921.2513730422/10/062
60735.731.80114303421/9/061
Run
End
Run
Start
Run EndRun Start
BW Interval (Minutes)Flux
( lm-2h-1 )
ResistanceTMP
(kPa)
DaysStart
Date
Run #
15
Pilot Plant Results
16
Pilot Plant Results
17
Comparison with Full-scale
18
Identified Benefits
Reduced energy
Reduced chemical consumption
Simplified CIP – Hypochlorite only
Reduced volumes to thickener – estimated at 25% the volume
with 4 times solids loading improving operation of thickener
19
One Step Beyond?
21
Thank You
