dcsimg How to achieve high quality water supply - Ramboll Group

How to achieve high quality water supply

The Danish Water Sector leads the way in regard to supply security and drinking water quality. New requirements are introduced to ensure high quality management at all waterworks. 
When Søren Hvilshøj, Ramboll's International Water Director recently received an Irish delegation led by the Irish junior environmental minister, the minister described their goal to decrease spillage levels of the Irish drinking water supply to 30%.

The current spillage rate in the city of Copenhagen at this time is only about five percent. And if spillage at Danish waterworks exceeds 10%, they get hit with a fine.

The Irish minister was clearly quite impressed, especially when Søren Hvilshøj referred, during the visit at a Danish water plant, to the use of the SCADA-System (Supervisory Control and Data Acquisition), and that spillage there is as low as 1-2%. At the same time, consumers all register their own water consumption online in Denmark.

In other words, there is a big gap between the Irish and Danish spillage rates. And while the Irish have installed water meters in consumers' homes – but so far only on a trial basis  –  they do not yet have a comprehensive view of whether consumers are paying a realistic price for their water supply or not. In Denmark, water meters were installed in Danish homes already many years ago.

Water without chlorine

When it comes to drinking water supply system, Denmark is far ahead of other countries, where actual water consumption is more or less guesswork, says Søren Hvilshøj. He explains why the Danish drinking water system is so unique, in addition to the fact that there is poured less chlorine into Danish water: 

"An important reason is that we carry out groundwater protection measures – and keep track of our groundwater resources in a much different way than in the rest of the world. It's really quite unique that we have mapped almost all groundwater resources  - and that we are in the process of drawing up plans for further groundwater protection at the individual waterworks".


Comparable to food

In the long run, it is envisioned that technology such as ultraviolet light and sensors, placed at drainage pumps on the supply net, will provide us with even higher quality water supply.

While ultraviolet light systems are already in use, the plans for the sensors are still in process.  But the VTU Fund (Foundation for Development of Technology in the Danish Water Sector) has funded development projects in sensor technology, reports Søren Hvilshøj, also board member in the VTU Fund.

At present, quality needs to be guaranteed through improved control at the waterworks. The approximately 2,500 Danish waterworks have throughout the years been accused of lack of adequate inspection of water quality and for not being professional enough in daily operations.

Digital tools help ensure groundwater quality

A sum of DKK 20 million annually in 2012 and 2013 have been used to increase our knowledge about the risks related to groundwater boreholes. Ramboll has developed a digital tool to help municipalities address this problem.

The optimal protection of groundwater resources is of crucial importance and will be in the future. Thus, the Danish parliament has earmarked DKK 20 million in 2012 and 2013 to protect the groundwater from threat of pollution that can occur in boreholes in connection with wells. 

The money will be used to identify and document the so-called sanitary protection zones of water intakes (BNBO), where the threat from pesticides and fertilizer is especially serious.

When the groundwater is pumped up from the boreholes, a kind of depression cone in the groundwater is formed around the borehole. Within the area of this cone, there is a greater risk of pollution from surface area that can trickle down into the groundwater.

Because of the specific soil conditions, the depression cone is not always circular. Therefore it is important to map the area of the depression cone for every specific borehole, the so-called BNBO.

Selecting the most relevant area

Thus municipalities can now apply for funding to identify the boreholes at greatest risk. To meet this aim, Ramboll has developed a special tool "BNBO-Tool" which describes the risk in the individual wells.
The tool is designed to cover parameters such as geology, hydrology, land use and quantity of pumped water, which can be shown on a GIS-map.

"We plot all the various parameters and then we can quickly use a GIS spreadsheet to identify the most relevant areas for protection," explains Annette Raben, Head of Ramboll's Water Department.

The end product is a risk assessment which Ramboll prepares on the basis of the emerging data.
The tool was developed in collaboration with the environmental advisory company, ConTerra, which works with land use and agricultural data. 

Facts on Danish groundwater 

1 billion m3: The total available groundwater resource is 1 billion m3.

17%: Approx. 17% of rainwater permeates into groundwater and can later be pumped up again as drinking water. 60% evaporates and 20% flows back to streams and the sea, via drains, sewers and paved areas.

20-50 year-old groundwater: The groundwater we usually recover is between 20-50 years old. Denmark's oldest groundwater is in Kristrup near Randers, where the water is 15,000 years old.

100%: 100% of the Danish drinking water supply is based on groundwater.

653 million m3: The total groundwater recovery is around 650 million m3.

Source: Danva/GEUS


For more information, please contact
Søren Hvilshøj
Søren Hvilshøj
Global Market Director, Water
T+45 51618245