Post on 25-Dec-2015
transcript
Prevention of filaments with aluminium or
ozone at Klagshamn WWTP?
Marika Wennberg*, Ulf Nyberg* and Karin Jönsson***VA SYD **Lund University
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.
90 000
Actual p.e.
70 000
Actual flow
800 m3/h
Discharge limits
BOD7 10 mg/l*
Tot-P 0.3 mg/l*
Tot-N 12 mg/l**
*monthly average**annual average
Aluminium treatment
Chemical: PAX-15 (polyaluminium chloride)
Dose: 1.2 g Al/m3
Simple technical equipment
Treatment performed 2006-2009
1-3 months
Focus 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 lines
2.5-months treatment
Dose: 550 g O3/h 0.006 g O3/g MLSS
Process parameters
MLSS-concentration: 3 g/L
Sludge age: 20 days at start-up
Water temperature: 14°C at start-up
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
Improved settling properties
0 10 20 30 40 50 60 70 80
0,0
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
Slu
dg
e a
ge
(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?