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Porlock Sewage Treatment Plant. Site data. Located in Exmoor National Park, with nearby bathing beach 3800 population equivalent (summer) 1900 m 3 /d flow to full treatment Sewage feed started 12th February 1998. Principle of Operation. In. Out. Screened crude sewage. - PowerPoint PPT Presentation
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• Located in Exmoor National Park, with nearby bathing beach
• 3800 population equivalent (summer)
• 1900 m3/d flow to full treatment
• Sewage feed started 12th February 1998
Porlock Sewage Treatment Plant
Site data
Principle of Operation
Screened crude sewage
Treated &disinfected
effluent
Air in
Waste Sludge(to further treatment)
In
Out
A Crap Commitment
Membrane Filtration
Air
Bacteria
Virus
Solids
Treated effluent
Membrane
Porlock Treatment Building
Tidal Storage
Blowers
PermeatePumps
Aeration Tanks1 - 4
Anoxic recycleTank
1.
2.
3.
4.
Membrane Units
Final Effluentout
Crude Effluentinlet
Fine Screens3 mm
Washing Tank
Porlock Aeration Tank MLSS
0
5000
10000
15000
20000
25000
30000
0 0.5 1 1.5 2Time in Years
MLSS (mg/l)
Aeration tank average
Feb 98 - Sept 99
Porlock BOD Removal
0
100
200
300
400
500
600
700
0 0.5 1 1.5 2Time in Years
BOD (mgO2/l)
Raw Feed Permeate
Feb 98 - Jan 00
Porlock NH3/4 Removal
0
10
20
30
40
50
200 250 300 350 400Time in Days
AmmN (mgN/l)
Raw Feed Permeate
Aug 98 - Apr 99
No ammonia consentNo dissolved oxygen control
Porlock Faecal Coliforms
0.0000010.000010.00010.0010.010.1
110
1001000
0 0.5 1 1.5 2Time in Years
Faec. Col.
106/100 ml
Raw feed Permeate
Feb 98 - Jan 00
Sampling contamination identified
Intensive sampling periods
0.0000001
0.000001
0.00001
0.0001
0.001
0.01
0.1
1
0 0.5 1 1.5 2Time in Years
Coliphage 105/ml
Feed coliphage Final coliphage (F+coliphage) (F+coliphage)
Porlock Faecal Coliphage Virus
Feb 98 - Jan 00
Change of test procedure
Porlock Final Effluent Turbidity
0
1
2
3
4
5
6
7
55 65 75 85 95 105 115 125Time in Days
NTU
Tank 1 Tank 2 Tank 3 Tank 4
Feb - June 1998
Turbidity meter set up incorrectly - readings higher than actual
Porlock STW- Compliance Results
June 1998 – November 1999
Crude FinalAnalyte
No ofsamples Min Max Average Min Max Average
Total coliforms /100 ml 36 4000000 >3000000000 233000000 <10 480 <44Faecal coliforms /100 ml 37 600000 160000000 16700000 <10 60 <11Faecal streptococcus /100 ml 36 40000 9400000 928000 <10 20 <10Clostridium Perfringens /100 ml 33 500000 1800000 144000 <10 90 <13Salmonella /10 litres 36 0 350 16 0 <10 <1.9Enterovirus /10 litres 32 < 200 360000 2300 <1 10 <1.4F+ coliphage /100 ml 29 40 1118000 154000 <1 60 <6.5Suspended solids mg/litre 30 32 1030 249 <1 8 <5Turbidity NTU 32 - - - 0.07 1.5 0.23BOD5 mgO2/litre 35 26 640 290 <2 <8 <5
Kubota Submerged Membrane Process
