I recently attended the IWA World Water Congress 2022 in Copenhagen, Denmark, as part of the Young Water Professionals Water Camp. It was a massive congress with over 10,000 delegates from around the world. The below is a summary of Denmark water utilities of things I learned during the event, with figures supplemented from DANVA (2022), Water in Figures: Statistics and Benchmarking, as well as a series of site visits with the water utility FORS.
Water Facts: Denmark vs UK
- Source water: 100% groundwater, although there is a small desalination plant in Christiansø. In England, 30% of drinking water sources are from groundwater and 70% from surface water.
- Drinking water treatment works: 2600. 1,069.
- Litres of water per person per day: 105. 142.
- Water loss: 7.22%. 23%.
- Drinking water pipes: 45,000 km. 347,636 km.
- Pipe network material: 50.9% PVC, 37.2% PE, 4.4% other, 3.4% grey cast iron, 2.6% eternit and 1.5% ductile cast iron. 50% cast iron, 16% PVC, 12% PE, 11% cement and some steel, copper, glass fibre reinforced plastics and lead. The pipe network material in the UK is not always known by the utility and not information usually shared between different utilities.
- Pipes have an expected service life of 75 years. Average pipe age in the UK is 75-80 years old but some pipes still in use today have been in use for over 100 years.
- Drinking water provided: 310 million m3 every year. 16.6 billion litres every day.
- Chlorine: 0 mg/l. ~1 mg/l at the water treatment works to achieve 0.5 mg/l at the tap.
- Denmark has a goal of becoming energy and climate neutral by 2030. In 2019, water companies in England joined forces to make a pledge to reach net zero on operational emissions by 2030.
- Separated (non-combined) sewer systems: 68%. ~17.5%.
- Sewer network: 85,850 km. 571,424 km.
- Wastewater plants: 701. 6,327.
- Discharged wastewater: 683 million m3 in a year. 11 billion litres of waste water in a day.
Finacials and Ownership
The cost of water in Denmark varies throughout the country.
But half a litre on average costs €0.50. That equates to €9.85
per m3, estimated using a household size of 2.12 people and a
consumption of 105 litres. This is ~1.41% of the average annual household
expenses. By law, water utilities are able to charge a fixed annual
administration fee per household as well as a charge per m3 of water
consumed, although some utilities only charge for the latter. In all, a water
utility’s expenditure and income must balance, with 100% of that income being
sourced from customers, of which there is a population in Denmark of 5.8
million. It is also required that if, for example, a water utility would like
to install a UV system, they require a permit from the government to do so
(this is not the case in England).
The cost for water in UK also varies by location, with 1 litre of water costing less than 1p. The 11
water and wastewater utilities in England (a population of 56 million) are privately
owned and are designed to generate a profit. Both Scotland (which has a population
of 5.5 million) and Northern Ireland (population 2 million) have only one public
sector-owned utility, Scottish Water and Northern Ireland Water, respectively. The
utility in Wales (population 3 million), Dŵr Cymru Welsh Water, is owned by a
company but is not for profit.
The average annual water utility bill in England was £408 a
year, or £34 a month in 2021/22. In England, bills are either calculated unmetered (a set
amount based on the rateable value of the home, a figure determined
by the government that estimates the value of a property) or metered (the domestic
water readings are taken from a water meter and consumers pay for the units of
water used).
Drinking Water Sampling
The Documented Drinking Water Safety (DDS) consists of tests
in selected chemical parameters (e.g. iron, manganese) and microbiological parameters
(e.g. E. coli and bacterial counts) in Denmark. The frequency of samples depends on the
size of the utility. 99.4% of 77 companies in 2021 met these regulations, from
14,030 accredited samples. 6 companies had to issue boil notices due to
microbiological exceedances, which impacted 11,405 households in 2021. The
water treatment works that I visited during my stay was Hornsherred Waterworks,
which supplies Roskilde, ~82,000 people. At the site I visited, final water was
sampled 2 x a week for microbial parameters and 1 x a fortnight for chemical
parameters.
In the UK, water treatment works are sampled every day at the Final Water (the final sample point before the pipe network) and is also sampled at the tap, with frequency depending on the population of the zone. During 2017 to 2019, public water supply compliance with the drinking water regulations was 99.95%. The below table shows the UK regulatory frequency of customer tap sampling.
Drinking Water Treatment
There is an emphasis in Denmark on having “simple treatment” although in recent years there has been some debate as to what this means. The below figure provides a drinking water treatment example in Denmark from FORS.
There can be advanced treatment process used in the UK, especially for surface sourced water treatment works. The below figure provides a drinking water treatment example in UK from Thames Water.
A Final Short Note on Culture
Danish drinking water production is considered in a similar way to food production. For example, plastic overshoes are worn when in the treatment plant, with different coloured lines on the floor indicating if that is a covered shoe only zone or if you are not allowed in a specific area at all. This is not something that happens in the UK.
