Chemicals Investigation Programme 2 · a centra-flo upflow moving bed reactive sand filter. •...
Transcript of Chemicals Investigation Programme 2 · a centra-flo upflow moving bed reactive sand filter. •...
Chemicals Investigation Programme 2
Continuous backwash gravity sand filters: experiences from BluePRO ® installations
Victoria Wilson1, John Williams1, Adam Brookes2, Tina Popple2, Pete Vale3, Luca Alibardi3
1 Dwr Cymru Welsh Water2 Anglian Water3 Severn Trent WaterThe Big Phosphorus Conference, Manchester, 4th and 5th July 2017
National Collaborative Project
Drivers and Objectives
How low can we go?
Is 0.1mg/l TP actually achievable with current or future technologies?
The national P TWG coordinated 3 approaches to answering this
question:
• Novel Technologies
• Optimisation
• Innovation
We will be covering one of the Novel Technologies - BluePro
CIP2 Low P Programme – BluePRO® trials objectives
• Technology utilised in USA achieving low level P limits 0.02mg/l
• Gain experience and understanding of operating at full scale
• “Hands off” operation – to be optimised before sampling
• Extensive programme of sampling – stakeholders agreed
• Determine the long term efficacy
• Understand CAPEX & OPEX costs of running the BluePRO
• 3 Sites across 3 Water Company’s- Anglian, Severn & Dwr Cymru
(Dwr Cymru was monitoring only & new 0.5mg/l Total P consent)
• Assess maintainability & operability
BluePRO® unit - continuous upflow sand filter
• Sand continuously moving down • Clean water up
(Continuous backwash)
• Sand is airlifted up to wash box
• Phosphorus ferric complex is removed through the patented wash box
BluePRO® – The mechanism
• Dynamic combination of both co-precipitation and adsorption processes. • Ferric chemical is dosed into the patented rapid conditioning zone and then feeds into
a centra-flo upflow moving bed reactive sand filter. • Hydrous ferric oxide coated sand (HFOCS) is formed within the reactive filter• HFOCS being the adsorbent media coating the sand. • The sand is spherical shaped and has an effective size of 1.0mm with a SG>2.5
Scanning electron microscope image of the Blue Pro Centra-Flo sand particles; followed by the x ray fluorescence image of iron coating the sand particle; finally an x ray fluorescence image of the phosphorus adsorbed onto the Hydrous Ferric Oxide.
Company PE site Upfront
Process
No. filters Trial max flow
Anglian Water 1,837 Biofiltration 1 14.1 L/s
Dŵr Cymru
Welsh Water2,107 Biofiltration 2
28 L/s (14 L/s per filter)*
Severn Trent
Water11,000 Biofiltration 5
88 L/s (17.6 L/s per filter)
CIP2 Low P Programme – BluePRO® trial sites
* TSS issues on site restricted the flow to the filters
Dŵr Cymru – BluePRO® trial site
• 2 no. Blue PRO® filters
(5.9m2 surface area, 1.5m depth, 2.7m diameter) per filter
• Max 20 L/s ( 10 L/s per filter)
• Ferric sulphate dose: 10-15 mgFe/L
• *Inf. TP = 1.0 – 3.0 mg/L
• *Inf OrthoP = 70% of TP
• *Inf. Alk = 70 - 130mgCaCO3/L
• *Inf TSS = 20 - 30 mg/L
* Requirement from supplier
Severn Trent – BluePRO® trial site
Primary Settlement Tanks
Biological Filters
Humus Tanks
Nitrifying Submerged Aerated Filter
Deep Bed Sand Filters
Blue PRO Filters
Inlet Works
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Final Effluent to River
Storm Tanks
Pre Trial Site Configuration
Trial Site Configuration
1 pH monitor
2 On line Fe monitor
Legend
Pumping Station
Pumping Station
Ferric sulphate dosing rig Reject pump
3
4
On line P monitor
On line Turbidity monitor
21
432
• 5 no. Blue PRO® filters
(each of 25m3, 3m diameter)
• Max 88 L/s (17.6 L/s per filter)
• Ferric sulphate dose: 10-13 mgFe/L
• *Inf. TP = 1.0 – 1.5 mg/L
• *Inf OrthoP = 0.3 – 1.1 mg/L
• *Inf. Alk = 70 - 130mgCaCO3/L
* Requirement from supplier
Anglian Water – BluePRO® trial site
Primary Settlement Tanks
Biological Filters
Humus Tanks
Blue PRO Filter
Inlet Works
Final Effluent to River
Pre Trial Site Configuration
Trial Site Configuration
Legend
Pumping Station
Reject tank
• 1 Blue PRO® filter
5.9m2 surface area, 1.5m depth
• Max 14.1 L/s
• Ferric sulphate dose: 12 mg Fe/L
• Inf. TP = 1.3 – 5.9 mg/L
• Inf. SRP = 1.2 – 5.3 mg/L
Ferric dosing
Programme sample
Results of BluePRO® trial – Summary of influent Total P
Company Average
TP
(mg/l)
Min TP
(mg/l)
Max TP
(mg/l)
Anglian Water 3.45 1.34 5.93
Dŵr Cymru
Welsh Water1.25 0.12 6.1*
Severn Trent
Water1.55 1.08 2.33
* Sampling was taken during a plugging event
Results of BluePRO® trial – Summary of effluent Total P
Company Average
TP
(mg/l)
95 %ile
(mg/l)
Min
(mg/l)
Max
(mg/l)
Averageremoval
(%)
Anglian Water 0.23 0.50 0.05 0.50 93
Dŵr Cymru
Welsh Water0.63(0.27)
2.49(1.33)
0.017.9*(1.8)
86.7
Severn Trent
Water0.19 0.60 0.06 0.82 88
* Sampling was taken during a plugging event. (Data without plugging event )
Dŵr Cymru – BluePRO® trial results
0
1
2
3
4
5
6
7
8
Co
nce
ntr
atio
n (
mg/
)
Soluble Reactive P (SRP)
Influent SRP
Effluent SRP
0
1
2
3
4
5
6
7
8
9
Co
nce
ntr
atio
n (m
g/)
Total Phosphorus (TP)
Influent TP
Effluent TP
Dwr Cymru – BluePRO® trial results
Severn Trent – BluePRO® trial results
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0
0.5
1
1.5
2
2.5
Effl
ue
nt
(mgP
/L)
Infl
uen
t (m
gP/L
)
Inf TP Eff TP
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0
0.5
1
1.5
2
2.5
Effl
ue
nt
(mgP
/L)
Infl
ue
nt
(mgP
/L) Inf SRP Eff SRP
Total Phosphorus (TP) Soluble Reactive P (SRP)
0
0.5
1
1.5
2
2.5
0 5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
10
0
(mgP
/L)
%ile
Inf TP
Inf SRP
Eff TP
Eff SRP
Severn Trent – BluePRO® trial results
-60
-40
-20
0
20
40
60
80
100
0.01
0.10
1.00
10.00
100.00
TP SRP TSS AMON BOD COD FED FET pH
Re
mo
val (
%)
(mg/
L)
Influent Effluent Removal
Anglian Water – BluePRO® trial results
0.0
1.0
2.0
3.0
4.0
5.0
6.0
SRP
(m
g/L)
SRP influent
SRP effluent
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
Tota
l P (
mg/
L)
TP influent
TP effluent
Soluble Reactive Phosphorus (SRP)
Total Phosphorus (TP)
Anglian Water – BluePRO® trial results
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
31/01/16 21/03/16 10/05/16 29/06/16 18/08/16 07/10/16 26/11/16 15/01/17
Dis
solv
ed
iro
n (
mg/
l)
Dissolved iron influent
Dissolved iron effluent
0
0.5
1
1.5
2
2.5
31/01/16 21/03/16 10/05/16 29/06/16 18/08/16 07/10/16 26/11/16 15/01/17
Tota
l iro
n (
mg/
L)
Total iron influent
Total iron effluent
Dissolved Iron
Total Iron
Anglian Water – BluePRO® trial results
0
1000
2000
3000
4000
5000
6000
7000
13/03/16 14/03/16 15/03/16 16/03/16 17/03/16 18/03/16 19/03/16 20/03/16 21/03/16 22/03/16 23/03/16 24/03/16
Tota
l P C
on
cen
trat
ion
(µ
g/l)
Date
South Witham Total P Concentrations - Composite Samples
Crude
Filter Feed
Filter Effluent
Challenges• Concerns with the ability of the system to cope with rapid flow changes
• The reject lines had to have frequent cleaning for blockages
(Severn Trent - filter 3 was particularly susceptible to the reject line
blocking; Dŵr Cymru both filters had blocking/plugging issues).
• Movement in horizontal and vertical plan of wash box has shown to
contribute to plugging events. Confined space entry currently to adjust
• The design of wash boxes and reject lines may have contributed to loss
of media seen under certain conditions.
• The feed solids and upfront feed pipework & pumping
• Issues with the upstream boll filter and bypass were encountered
initially.
Lessons Learned• Monthly spot samples might not be enough to evaluate the
performance of a new low-P technology, especially when the site permit will be based on composites.
• A new technology requires a greater process support, especially at the start of operating the process.
• BluePRO performance is best when the rate of change in flow is low.
• Control philosophy and cut in/out set points to avoid excessive flow variations.
• Flow control of more than one filter is critical to controlling headlossand shut down.
• BluePro susceptible to TSS levels <5 mg/L and 30 mg/L
• Contact tank not sure is required and settled solids
• Going from one to two filters -design, flow & dose control complicated
• Installing separate Points of Application dose points is needed
Next Steps
• Resolve the wash box weaknesses
• Improve the maintenance of internals and remove requirement of
confined space entry
• Resolve the critically important spares – delivery time not good
enough to meet the compliance limits
• Consistency & improvement of control philosophy to remove
weakness with flow control.
• Sand plugging detection to prevent loss
Thank you for your attention.
Questions?