http://www.aquafin.be/nl/index.php

1. Waste Water Treatment Plant Case Study
Aartselaar
Aquafin
MAIS AL JUBORI
HANNES DECADT
MOHAMMED HERZALLAH
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April 2015

2. Outline
 Introduction
 General Scheme of the WWTP
 Description of the WWTP
 Calculations
 Problems and Possible Solutions
 Conclusion
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3. Introduction
 Aquafin is a regional wastewater treatment company in
Flanders.
 Mission: expanding, operating and financing the sewage
treatment infrastructure in Flanders.
 responsible for the operation of 287 sewage treatment
plants distributed over the 5 provinces of Flanders.
 Each plant recives household wastewater collected
from the municipal sewers and treats it according to the
European and Flemish standards.
 Aquafin Aartselaar is one of these plants, located in
province of Antwerp and serves the population of the
zone Aartselaar and part of Wilrijk using the biological
treatment.
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4. GENERAL
SCHEME
OF THE
WWTP
Aartselaar
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5. Description of the WWTP
A. Collectors and screw system
B. Sand traps
C. Selector, anaerobic and anoxic tank
D. Aeration tanks
E. Sedimentation tanks
F. Sludge handling
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screw system
Sand traps
Selector tank
Anaerobic tank
Aeration tank with surface aerator
Sedimentation tank
F
A B C
D E

6. Calculations
Nitrification-denitrification
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Nitrification:
NH4
+ O2  NO3
-
Denitrification:
NO3
- N2
Unaerated tanks Aeration tanks
Recycling
Selector
Anaerobic
Anoxic
Facultative aerated
Aerobic

7. Calculations
Phosphate removal
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Growth
P-uptake
Selector
Anaerobic
Anoxic
Facultative aerated
Aerobic
PHB forming
P-release
Unaerated tanks Aeration tanks
Recycling

8. Calculations
Removal efficiencies
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9. Qinf = 28875 m³/d
= 5962 m³/d
G
= 444 m³/d
TT
= 28818 m³/d=51788 m³/d
Xt = 70 kg/m³
= 28488 m³/d
= 22526 m³/d
= 22970 m³/d
Qtot = 57750 m³/d
Unaerated tanks
2500 m³
Aeration tanks
5600 m³
Settle tanks
4242 m³
Xeff = 14.6 g/m³X = 4 kg/m³
= 387 m³/d
= 57 m³/d
Xw = 9 kg/m³
Qsi
Qr’
Qr
Qr+Qr’
Qreflow G+TT
Qt
Qso
Qw
Qeff
ΔX=4000 kg sludge/d
Calculations
Flow scheme

10. Calculations
Sludge-related parameters
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11. Calculations
Oxygen demand & aeration costs
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30%
€0.15/kWh

12. Problems and Possible Solutions
 The high concentration of the suspended solids in the effluent
 Poor nitrogen removal
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- Improving NH4
+-removal: longer sludge residence time
- Improving NO3
--removal: recycling more or making the anoxic zone larger
- Turn-off the paddlers of the aeration tanks to let the sludge settle down
calmly
- Use of membranes

13. Conclusion
 Typical conventional activated sludge system with recycling
for biological treatment of COD, nitrogen and phosphate
 Removal efficiencies reach the actual quota, but can be
bettered:
 The COD is removed properly
 Concentration of suspended solids has to be carefully followed
up
 Removal of nitrogen could be improved by more recycling
 Biological phosphate removal works satisfied
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