This document provides an overview of the Aartselaar Waste Water Treatment Plant operated by Aquafin. It describes the general treatment process which includes sand traps, selectors, anaerobic tanks, aeration tanks, and sedimentation tanks. Calculations are shown for nitrification, denitrification, phosphate removal, and removal efficiencies. Issues like high suspended solids in effluent and poor nitrogen removal are discussed along with potential solutions like increasing sludge residence time and anoxic zone size. The conclusion states that while removal targets are met, nitrogen removal could be improved with more recycling.

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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