problem filamentous microorganisms solution aluminium or ozone? control of sludge age?
DESCRIPTION
Prevention of filaments with aluminium or ozone at Klagshamn WWTP? Marika Wennberg*, Ulf Nyberg* and Karin Jönsson** * VA SYD **Lund University. Problem Filamentous microorganisms Solution Aluminium or ozone? Control of sludge age?. Aluminium. Ozone. Dimensioned p.e. 90 000 Actual p.e. - PowerPoint PPT PresentationTRANSCRIPT
Prevention of filaments with aluminium or ozone at Klagshamn WWTP?
Marika Wennberg*, Ulf Nyberg* and Karin Jönsson***VA SYD **Lund University
ProblemFilamentous microorganisms
SolutionAluminium or ozone?
Control of sludge age?
Aluminium Ozone
0 10 20 30 40 50 60 70 800
40
80
120
160
200
240 Experimental line Control line
DS
VI (
ml/g
)
Days of ozone addition0 10 20 30 40 50 60 70 80 90 100
0
40
80
120
160
200
240 06 07 08 09
DS
VI (
ml/g
)
Days of aluminium addition
Dimensioned p.e. 90 000Actual p.e. 70 000Actual flow800 m3/h
Discharge limitsBOD7 10 mg/l*Tot-P 0.3 mg/l*Tot-N 12 mg/l**
*monthly average**annual average
Klagshamn WWTP
Effects of filaments
Aluminium treatmentChemical: PAX-15 (polyaluminium chloride)Dose: 1.2 g Al/m3
Simple technical equipmentTreatment performed 2006-20091-3 monthsFocus on DSVI (ml/g)
Four periods of Al-treatment – four different outcomes
0 10 20 30 40 50 60 70 80 90 1000
40
80
120
160
200
240 06 07 08 09
DS
VI (
ml/g
)
Days of aluminium addition
Ozone treatmentFull-scale test, performed in one of the two lines2.5-months treatmentDose: 550 g O3/h 0.006 g O3/g MLSS
Process parametersMLSS-concentration: 3 g/LSludge age: 20 days at start-upWater temperature: 14°C at start-up
Process layout
Ozone makes a difference
0 10 20 30 40 50 60 70 800
40
80
120
160
200
240 Experimental line Control line
DS
VI (
ml/g
)
Days of ozone addition
No ozone Ozone
No ozone Ozone
Improved settling properties
0 10 20 30 40 50 60 70 800,0
0,5
1,0
1,5
2,0
2,5
Slu
dge
leve
l (m
)
Days of ozone addition
Experimental line Control line
Effects on nitrification
Lower nitrification rate (mg NH4-N/gVSS,d) in experimental line during lab tests
Higher concentrations of NH4-N in secondary effluent in experimental line
Control of sludge age
2009-03-10 2009-04-18 2009-05-27 2009-07-05 2009-08-13 2009-09-210
40
80
120
160
200
240
280
DSVI Measured sludge age Theoretical sludge age
DS
VI (
ml/g
)
0
10
20
30
40
50
Sludge age (d)
Estimated costs
Operating cost
Investment cost
Total cost
Ozone 48 000 250 000 298 000
Aluminium 32 000 5 000 37 000
Removal of floating sludge 300 000
(SEK/year)
Dosing of Aluminium was and was not…Ozonation was…Controlling aerobic sludge age was not… …an option to prevent filamentous growth at Klagshamn WWTP.
What did we learn?
Acknowledgements
KemiraAir LiquideOperational and laboratory staff at Klagshamn WWTP