Nikisch N.

Sieker H.

Sommer H.

I-Revues

SESSION 3.2 
NOVATECH 2007  735 
Reduction of pollution load from street-runoff by 
an inlet-filtration-system filled with adsorptive 
material  
Réduction de la pollution des eaux de ruissellement de chaussées 
avec un système de filtration aux avaloirs utilisant un matériau 
absorbant 
Sommer H.*, Nikisch N.**, Sieker H.*  
* Ingenieurgesellschaft Prof. Dr. Sieker mbH, Rennbahnallee 109, D-15366 
Hoppegarten, h.sommer@sieker.de, h.sieker@sieker.de  
** Hamburger Stadtentwässerung, Bankstr. 4-6, D-20097 Hamburg, 
norbert.nikisch@hhse.de  
RESUME 
La pollution des eaux de surface  par les ruissellements de chaussées devient un 
problème crucial comme le montrent plusieurs études nationales et internationales. Il 
existe différentes stratégies de réduction des ruissellements urbains. L’une consiste à 
réduire la charge polluante vers les cours d’eau et les lacs par le biais de retenues 
centralisées, de bassins de purification et de zones humides artificielles centralisées. 
Le contrôle à la source est une stratégie alternative. Cet article présente une solution 
pour les milliers d’avaloirs des voies urbaines qui drainent les ruissellements pollués 
des rues et des routes. Il s’agit d’une cartouche qui peut être insérée dans les 
avaloirs. Le flux entrant est traité en deux étapes de filtration - décantation et filtration.  
ABSTRACT 
Pollution of surface waters by runoff from sealed areas is coming more into focus. As 
shown by several national and international studies, this part of wastewater cannot be 
neglegted. There are different strategies to reduce emission from urban runoff. One is 
to reduce the pollution load to rivers and lakes by centralised retention, purification 
tanks and centralised constructed wetlands.  
An alternative strategy is source control. The presented solution in this paper 
concerns the thousands of inlets in urban areas draining highly polluted runoff from 
roads and highways. This solution consists of a cartridge that can be inserted into 
standard inlets. Within 2 filtration steps, a settling volume and an adsorptive filtration, 
the inflowing runoff is treated. 
The results of the quality measurements are : 
• a mixture of special filter sand with an adsorptive material is suitable for different 
inorganic and organic compounds. 
• a high retention for suspended solids was found 
• a significant reduction for heavy metals (zinc and copper), o-phosphate, and 
PAC was observed. 
KEYWORDS 
Heavy Metal, Pilot Plant, Stormwater, Surface Runoff, Treatment, Urban drainage. 
SESSION 3.2 
736 NOVATECH 2007  
1 INTRODUCTION 
Pollution of surface waters by runoff from sealed areas is coming more into focus. As 
shown by several national and international studies, this part of wastewater cannot be 
neglegted. In Germany, it is estimated that around 50% of the total pollution load 
emitted to rivers is discharged by separated sewers and overflows from combined 
sewers. In the case of separated sewer systems, there is usually no treatment 
provided. 
Until now stormwater treatment in separated sewer systems is usually done by end-
of-the-pipe solutions. These are mostly stormwater clarification tanks, some soil filters 
or chemical treatment plants (sedimentation after flocculation). The principles, based 
only on the sedimentation process, are to be seen critically, because the effect on 
reduction of heavy metals and nutritions is too low. Soil filters are preferred. 
However, these end-of-pipe-technologies have several disadvantages: 
• The level of a sewer system is usually 2-4 m below ground level. Therefore, the 
inlet to the central treatment facility (i.e. soil filter) must be as deep as the sewer 
system, which is not possible in mostly flat regions like the northern part of 
Germany. This means that the amount of water which is treated has to be 
pumped to a higher level or this type of plant cannot be realized. 
• Because of the position at the end of the sewer system, only a mixture of 
polluted stormwater can be treated. There is no separate treatment for highly 
polluted runoff from streets and highways and low polluted runoff from other 
areas (i.e. roofs) possible. 
• At the end of the pipe, the amount of water to be treated is mostly so high that 
only a part can be handled by the centralized plants. 
An alternative strategy is source control. The presented solution in this paper 
concerns the thousands of inlets in urban areas draining highly polluted runoff from 
roads and highways. 
Therefore, a new on-site system of stormwater runoff treatment was developed which 
purifies the highly polluted runoff on-site. This method uses the difference in height 
from ground level to sewer level. This system is called INNOLET® and can be 
integrated into newly built inlets or installed into existing ones. 
Projects in USA and Denmark have shown, that runoff filters have been developed 
(Claytor, 1996) and suitable adsorptive filter materials are available (Möller et.al., 
2002). In a project in Switzerland adsorptive filter material was used for reduction of 
copper in the runoff from a roof covered with copper. (Frenzel et al., 2001) 
 
2 POLLUTION FROM RUNOFF IN URBAN AREAS 
There are a number of pollutants from runoff in urban areas which have an impact on 
the receiving water. However, there is a certain difference between runoff from streets 
and from roofs. Runoff from streets generally has a higher content of pollutants. 
SESSION 3.2 
NOVATECH 2007  737 
 
  Streets    roofs    
 unit Count Medium Minimum Maximum count Medium min max 
PH  4 7.0 6.4 7.6 3 6.1 5.9 6.3 
Cond. mS/cm 8 136.6 69.2 342.5 3 91.7 66.0 129.0 
TSS mg/l 11 210.2 37.5 980.0 2 51.6 43.2 60.0 
TOC mg/l 2 17.2 6.6 27.8 0 n.v. n.v. n.v. 
COD mgO2/l 17 88.1 13.2 260.0 3 30.8 22.0 37.0 
AOX mg/l 6 136.5 12.8 600.0 0 n.v. n.v. n.v. 
Ptot mg/l 8 0.9 0.1 3.0 1 0.1 0.1 0.1 
PO4-P mg/l 6 0.1 0.0 0.2 0 n.v. n.v. n.v. 
Ntot mg/l 3 2.8 1.8 4.1 1 9.0 9.0 9.0 
NO3-N mg/l 11 0.8 0.4 1.5 1 0.2 0.2 0.2 
NH4-N mg/l 11 1.0 0.2 2.4 1 4.0 4.0 4.0 
HC mg/l 8 0.3 0.0 0.7 0 n.v. n.v. n.v. 
BOD5 mg/l 11 15.0 1.1 28.0 0 n.v. n.v. n.v. 
PAH mg/l 5 1.9 0.6 3.1 1 0.5 0.5 0.5 
Cd mg/l 10 5.2 0.0 20.0 1 1.0 1.0 1.0 
Zn mg/l 14 687.9 80.0 1950.0 1 24.0 24.0 24.0 
Cu mg/l 11 76.0 6.0 380.0 1 35.0 35.0 35.0 
Pb mg/l 14 180.2 9.4 980.0 1 104.0 104.0 104.0 
n.v. = no value, cond. = conductivity, TSS = total suspended solids, HC = Hydrocarbon 
Table 1 : Contents of different compounds in runoff from streets in comparison with runoff from 
roofs (Förster and Herrmann, 1996; Göttle, 1978; Grottker, 1987; Hahn and Xanthopoulos, 1995; 
Heinzmann 1993; Paulsen 1987; Sommer et.al., 2002; Xanthopoulos, 1990) 
 
In the table it can be seen, that compared to roofs, the values for heavy metals, HC, 
AOX and COD are higher in runoff in particular from streets. Nutritions like 
Phosphorus are responsible for euthrofication of the receiving waters. In the literature 
it is acknowledged that high concentrations can be found in runoff from highly 
travelled roads. (Grottker, 1987) remarks that different pollution loads of heavy metals 
are obtained from different road types. 
Another problem is that several compounds and heavy metals are adsorbed at 
different grain sizes. 60-90% of the heavy metals in the runoff are adsorbed to the 
smallest fraction of grain in the runoff, which means that it must be in the suspended 
fraction and will not settle in a settling tank. (Xanthopoulos, 1990) 
3 PURIFICATION METHOD : INNOLET®-SYSTEM 
The idea of the INNOLET® Filtration-System is to reduce the high pollution in runoff 
from heavily travelled streets and highways. Two systems have been developed. The 
first system is the INNOLET® gutter. It is an implementation of a filter in a standard 
gutter that is suitable for renewal of streets and new built roads. 
The INNOLET® filter cartridge instead can be easily applied into the existing inlets, 
built according to the German DIN, without any change of the inlet. (Sommer, 
2003),(Sommer and Sieker, 2004)  
 
SESSION 3.2 
738 NOVATECH 2007  
 
Figure 1 : Drawing of the INNOLET®-filter cartridge placed in a standard German inlet 
 
The INNOLET® filter cartridge is a 2 step filter unit. The first step is a sedimentation 
and filtration of bigger particles like sand or leaves. In the second step an adsorptive 
material is reduced to reduce soluble compounds. The adsorptive material is an 
granulated iron hydroxide which is capable to remove heavy metals and phosphate. 
Both parts are inserted into a containing cartridge. 
For evaluating the hydraulic behaviour of runoff in the system, a model inlet was built. 
The results from these pre-measurements were the basis for changing and optimizing 
the design of the system. 
If the filter is not able to handle the amount of runoff to the inlet, overflows directly to 
the sewer assure that the environment is not flooded. 
The studies showed that the proposed flow rate could be reached with a special 
selection of filtration material. The best results were with a filtration sand with a steep 
distribution curve. The sieve curve of dust from streets is much smoother, because 
the quota of small particles that will be suspended in the runoff is higher.  
4 RESULTS 
4.1 Hydraulic aspects 
 
The aim was to treat a runoff rate of 7-15 l/(s*ha) (2.5-5.4 mm/h) in the filtration area 
according to the the dimensioning of conventional rain water tanks. The first task was 
to optimise the flow rate and the filtration time. Table 2 shows the filtration speed and 
filtration time for the 2 systems. 
SESSION 3.2 
NOVATECH 2007  739 
 
 Filter speed  Filtration time 
 (m/s) (m/s) (s) 
INNOLET gutter 0.001 1.0E-03 100 
INNOLET filter cartridge 0.005 5.0E-03  20 
Table 2 : Filtration speed 
 
With these operating conditions is was possible to filtrate 3 quarter of the runoff as 
shown in the water balance in table 3. 
 
 Inflow overflow treated treated not 
treated 
overflows 
 (m³/a) (m³/a) (m³/a) (%) (%) (N/a) 
INNOLET® gutter 114.78 26.5 88.22 77 23 67 
INNOLET® filter 
cartridge 
114.66 25.17 89.48 78 22 71 
Table 3 : water balance for an area of 320 m² per INNOLET®-Element 
 
4.2 Quality Aspects 
Preliminary tests with potential adsorption material showed that some compounds 
have a higher concentration in the outflow than in the artificial storm water. For further 
tests it was decided to use iron oxide and zeolithe. Following filtration materials were 
selected and tested. 
 
FerroSorb Plus (Ironoxide) 
FerroSorb RWR (Ironoxide plus Zeolithe)
Table 4 : Selected material for adsorption of different compounds in runoff 
The main aim was to reduce heavy metals and phosphorous compounds in the 
outflow of the filter. Other target parameters were hydrocarbons and polyaromatic 
hydrocarbons (PAH).  
 
name   Unit Load Load load Total 
outflow 
load 
  Input overflow  filtrate Purified reduction 
Artificial 
rainwater 
(m³/a) 114.66 25.17 89.48  
TSS (kg/a) 196.30 43.09 61.28 104.37 47% 
Cu (g/a) 2.19 0.48 1.20 1.68 23% 
Zn (g/a) 17.82 3.91 5.56 9.48 47% 
PAH (g/a) 15.73 3.45 6.14 9.59 39% 
o-PO4-P (g/a) 45.23 9.93 14.12 24.05 47% 
Table 5 : pollution load balance, results of adsorption experiments with artificial runoff 
stormwater 
SESSION 3.2 
740 NOVATECH 2007  
The results of the load balance of the runoff showed a reduction from around 20% 
(Cu) up to nearly 50% (TSS, ZN, o-PO4-P). The base of these calculations were the 
experiments with artificial runoff stormwater which offer the opportunity to measure in 
differents stages of usage. 
 
5 PILOT SITE HAMBURG 
Within the Urban Water Cycle project, an EU Interreg IIIb North Sea Region project, 
the City of Hamburg and the Hamburg Sewage Service is partner of the project.  
One of the aims of the Hamburg UWC projects is the purification of storm water 
before running into the receiving water. One possibility is the treatment of the runoff at 
the source. Therefore, the innovative filtration system INNOLET®, which can be 
applied to standard inlets, was selected for treatment in a road with high daily traffic 
load (more than 35.000 veh/d) in the project catchment of “Mittlere Bille”. The road is 
one of the main through roads of the suburb of Hamburg Bergedorf. It is swept once a 
week by the public cleaning company. 
 
Figure 2 : INNOLET® filter cartidges were implemented in “Mittlere Bille” catchment area, parts 
from the left: cartridge, filter filled with adsorptive material, retainment of larger particles like sand 
and leaves 
   
Figure 3 and 4 : INNOLET® filter cartidges after one month inserted in the gully, right 
pictures shows the retention of leaves  
SESSION 3.2 
NOVATECH 2007  741 
19 pilot cartridges of the INNOLET® system were inserted into inserted existing inlets. 
Therefore the existing inlets were rebuilt. These inlets are monitored monthly for 
maintenance. No quality measurements are made in this period. 
The first results are: 
1. The street has high TSS-load with app. 1000 mg/l  
2. The INNOLET filters retain a large amount of TSS (Sand and leaves) in the 
bucket . 
3. The INNOLET filter also retains a large part of the small grain size fraction 
on the filter surface.  
4. Less than one day per week street sweeping is not efficient enough to 
reduce the high amount of TSS from the street. In a corresponding project in 
a similar road  (NORIS, Hanover) the frequency is 3 times a week. The TSS 
load which is flushed the inlets in rainfall events is far lower. 
5. The maintenance frequency of the buckets is considered to be once a 
month at the moment. This includes the cleaning the buckets. The 
maintenance frequency of the filter considered to be half a year. After one 
year the filter material shall be replaced. 
6 CONCLUSION 
With INNOLET®, a new way of reducing pollutants from street runoff was presented. 
In hydraulic experiments on the pilot plant, the usability of the system was verified. 
There were several optimisations on retention and the adsorptive material. Finally a 
sufficient flow rate and a good retention of particles could be achieved. The flow rate 
is highly dependent on the distribution of corn fractions in the filtration material. 
The system was then tested for 2 years on-site in inlets of a road in an industrial area. 
The practical hydraulic tests showed good results. A problem hereby is to prevent the 
filter from clogging with small suspended particles. An exchange time of 0.5-1 year for 
the filter can be expected. 
The results of the quality measurements are: 
- a mixture of special filter sand with an adsorptive material is suitable for the 
reduction of different inorganic and organic compounds. 
- a high retention for suspended solids was found 
- a significant reduction for heavy metals (zinc and copper), o-phosphate, and 
PAC was observed. The results for other parameters were insignificant. 
The System INNOLET® is a suitable treatment method for catchment areas with 
highly polluted roads or spatial restrictions for centralised treatment plants. It can be 
applied in existing gullies. 
First results in a Urban Water Cycle pilot catchment, located in Hamburg in a road 
with high daily traffic, show, that INNOLET can retain the most of TSS in the run off. 
The second filter step retains also the smaller grain size fraction which is meant to 
keep the highest amount of heavy metals. In roads with high TSS load the 
maintenance frequency should be adjusted to more than once a week. 
The results will be integrated into a catchment-wide simulation with the source & flux 
model STORM-SEWSYS with different scenarios. 
SESSION 3.2 
742 NOVATECH 2007  
ACKNOWLEDGEMENT 
The development of the INNOLET® filters was supported by the Federal Ministry for 
Education and Research and the Federal Ministry for Economics and Labour of 
Germany. Further investigations were funded by the EU program Interreg IIIb North 
Sea Region. 
 
LIST OF REFERENCES  
Claytor, R.S., T. (1996): “Design of Stormwater Filtering Systems.” , Center of Watershed 
Protection, prepared for Chesapeake Research Consortium, funded by US EPA, Region 5, 
Ellicott City. 
Förster, J. & Herrmann, R. (1996): “Eintrag und Transport von organischen Umweltchemikalien 
über verschiedene Dächer in das Kanalsystem”, Forschungsgesellschaft, D., Stoffaustrag 
aus Kanalisationen: Hydrologie bebauter Gebiete,, S.24-41. 
Frenzel, I.; Steiner, M. & Boller, M. (2001): Untersuchungen zum Kupferabtrag einer 
Kupferfassade und zur Wirksamkeit einer Eisenhydroxid-Sickerschicht zur Abtrennung von 
Kupfer aus dem Fassadenwasser, Zwischenbericht 1, 06/2001, Zürich 
Göttle, A. (1978): Ursachen und Mechanismen der Regenwasserverschmutzung - Ein Beitrag zur 
Modellierung der Abflussbeschaffenheit in städtischen Gebieten, Institut für 
Bauingenieurwesen Technische Universität München, Berichte aus Wassergütewirtschaft 
und Gesundheitsingenieurwesen, Heft Nr. 23. 
Grottker, M. (1987): Regenwasserbehandlung in Trennsystemen, Mitteilungen des Institutes für 
Wasserwirtschaft, Hydrologie und landwirtschaftlichen Wasserbau, Universität Hannover, 
Heft 66. 
Hahn, H. & Xanthopoulos, C. (1995): Integrale Ansätze zu einer effizienten Gestaltung der 
Stoffkreisläufe in Stadtgebieten, in Schadstoffe im Regenabfluß III, Universität Karlsruhe, I. f. 
S., Präsentation eines BMBF-Verbundprojektes, Band 73. 
Heinzmann, B. (1993): Beschaffenheit und weitergehende Aufbereitung von städtischen 
Regenabflüssen, Umwelttechnik, Fortschritt-Berichte VDI, Reihe 15, Nr. 113, VDI-Verlag, 
Berlin. 
Möller, J., Ledin, A., Mikkelsen, P.S. (2002): First World Wide Workshop for Junior Environmental 
Scientists, Removal of dissolved heavy metals from pre-settled stormwater runoff by iron-
oxide coated sand (IOCS). 
Paulsen, O. (1987): Kontinuierliche Simulation von Abflüssen und Stofffrachten in der 
Trennentwässerung, Hannover, U., Mitteilungen des Institut für Wasserwirtschaft, Hydrologie 
und landwirtschaftlichen Wasserbau, Heft 62. 
Sommer H.; Engel N.; Rehfeld-Klein M. & Sieker F. (2002): “Messtechnische Untersuchungen 
zur Funktion eines Mulden-Rigolen-Systems”, GWF-Wasser/Abwasser, Oldenburg Verlag 
München, 2002 Nr. 12, München. 
Sommer, H. (2003): Treatment of runoff from streets by inlet-filtration-systems; Filtech Europe 
2003, International Conference and Exhibition Filtration and Separation Technology, 
Proceedings, L-sessions, p. I-404-I-409 
Sommer, H.; Sieker, F. (2004): Endbericht „Untersuchungen zur Entwicklung eines mit 
auswaschbarem Filtermaterial ausgestatteten neuartigen Straßenablaufs“; gefördert durch 
das BMBF; Förderkennzeichen 02WA0262; 03/2004 
Xanthopoulos, C. (1990): “Niederschlagsbedingter Schmutzstoffeintrag in Kanalsystemen - 
Erneute Bilanzierung aufgrund weitergehender Erfassung von Ereignissen”, Schriftenreihe 
des Instituts für Siedlungswasserwirtschaft der Universität Karlsruhe, Heft 58, S. 117-145,. 
 
 
 


Réduction de la pollution des eaux de ruissellement de chaussées avec un système de filtration aux avaloirs utilisant un matériau absorbant

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Réduction de la pollution des eaux de ruissellement de chaussées avec un système de filtration aux avaloirs utilisant un matériau absorbant

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