Delft University of Technology
Faculty of Civil Engineering and Geosciences
Section of Sanitary Engineering
CT5520 – Drinking water treatment 2
Design project
Loenderveen (Waternet) – Enhancing NOM removal
prof.ir. J.C. van Dijk / ir. A. Grefte / Dr.ir. B. Heijman / Dr.ir. L.C.Rietveld
April 2007
,1. Problem definition
The presence of natural organic matter (NOM) in drinking water influences both the efficiency of
treatment steps, and processes in the distribution network such as the formation of biofilms and the
uptake of copper and lead.
Seepage water of the Bethunepolder is used as source for drinking water. This water contains much
NOM and enhanced NOM removal is required. Develop practical alternatives for the enhanced
removal of NOM to solve the problems related to high NOM concentrations. Think about:
• Choice of the system and the materials/media used.
• Place of the system in the pre-treatment (before or after coagulation).
• Variations in source water quality
• Effects of NOM removal on following treatment steps
Detailed information of Treatment plant Loenderveen is given in the annexes.
2. Actual situation
Mostly seepage water from the Bethunepolder is used as source water, but at low water levels in the
polder it is also possible to abstract water from the Amsterdam-Rhine canal.
The treatment at Loenderveen consists of coagulation, self-purification in a lake with a residence
time of 100 days and rapid sand filtration.
After this pre-treatment, the water is transported to Weesperkarspel.
The post–treatment at Weesperkarspel consists of: ozonation, softening, activated carbon filtration
and slow sand filtration.
An overview of several parameters in the raw water is given in table 1:
The treatment plant is characterised by the following data:
Design capacity:
The design flow of the treatment plant can be determined with the following data:
Year capacity: 15 mln m3
Average daily capacity: 47,000 m3/dag
Maximum day factor (peak fac¬tor): 1.8
Minimal day factor: 0.7
Coagulation:
Number of basis 2
Surface area per basin: 40x80 m
Lake water reservoir:
Residence time: about 100 days
Surface area: 123 ha
Volume: 6.9 million m3
,Filters:
Number: 24 filters
Surface area: 48 m2 per filter
Max. filter loading: 6 m/h
Transport mains:
Length: 10 km
Diameter: 2 x 1000mm
Buffering reservoir:
Surface area: 1.12 ha
Volume: 40.000 m3
, Annexes:
1. Water quality
2. Proces scheme
3. Main water flow scheme
4. Hydraulic line scheme
5. Map
Faculty of Civil Engineering and Geosciences
Section of Sanitary Engineering
CT5520 – Drinking water treatment 2
Design project
Loenderveen (Waternet) – Enhancing NOM removal
prof.ir. J.C. van Dijk / ir. A. Grefte / Dr.ir. B. Heijman / Dr.ir. L.C.Rietveld
April 2007
,1. Problem definition
The presence of natural organic matter (NOM) in drinking water influences both the efficiency of
treatment steps, and processes in the distribution network such as the formation of biofilms and the
uptake of copper and lead.
Seepage water of the Bethunepolder is used as source for drinking water. This water contains much
NOM and enhanced NOM removal is required. Develop practical alternatives for the enhanced
removal of NOM to solve the problems related to high NOM concentrations. Think about:
• Choice of the system and the materials/media used.
• Place of the system in the pre-treatment (before or after coagulation).
• Variations in source water quality
• Effects of NOM removal on following treatment steps
Detailed information of Treatment plant Loenderveen is given in the annexes.
2. Actual situation
Mostly seepage water from the Bethunepolder is used as source water, but at low water levels in the
polder it is also possible to abstract water from the Amsterdam-Rhine canal.
The treatment at Loenderveen consists of coagulation, self-purification in a lake with a residence
time of 100 days and rapid sand filtration.
After this pre-treatment, the water is transported to Weesperkarspel.
The post–treatment at Weesperkarspel consists of: ozonation, softening, activated carbon filtration
and slow sand filtration.
An overview of several parameters in the raw water is given in table 1:
The treatment plant is characterised by the following data:
Design capacity:
The design flow of the treatment plant can be determined with the following data:
Year capacity: 15 mln m3
Average daily capacity: 47,000 m3/dag
Maximum day factor (peak fac¬tor): 1.8
Minimal day factor: 0.7
Coagulation:
Number of basis 2
Surface area per basin: 40x80 m
Lake water reservoir:
Residence time: about 100 days
Surface area: 123 ha
Volume: 6.9 million m3
,Filters:
Number: 24 filters
Surface area: 48 m2 per filter
Max. filter loading: 6 m/h
Transport mains:
Length: 10 km
Diameter: 2 x 1000mm
Buffering reservoir:
Surface area: 1.12 ha
Volume: 40.000 m3
, Annexes:
1. Water quality
2. Proces scheme
3. Main water flow scheme
4. Hydraulic line scheme
5. Map
