Unlocking the potential of wastewater

On a global scale, less than half of all wastewater is collected and less than one fifth is treated. This and the threat of water scarcity underline the need for more efficient and smarter wastewater treatment across the world. This white paper provides lessons learned from Danish stakeholders within wastewater treatment.

The lack of proper wastewater treatment can result in severe environmental degradation of inland and sea waters around the world. Water scarcity and population growth, furthermore, underline the importance of treating and understanding the value of wastewater.

Energy producing wastewater treatment plants

Approximately 2% of the world’s total energy consumption is used for collecting and treating wastewater.

In Denmark, 2-3% of the country’s total energy use relates to

As a result, most Danish wastewater treatment plants have invested in an assessment of different ways to reduce their energy consumption and are increasingly focusing on energy production. As a next step, some water utilities are also looking into recovering the heat from the wastewater before it is discharged with the additional benefit of reducing the temperature impact on the receiving waters.

Using wastewater as a resource

Considering wastewater a resource is a relatively new perspective. However, today it is widely recognised that the organic content in the wastewater can be a resource for energy production and phosphorus can be used for fertiliser production with several advantages compared to the application of sewage sludge on agricultural land. Finally, the water itself can be cleaned to such high standards that it can be reused in a number of ways – e.g. for flushing toilets, laundry machines or irrigation for crops.

Find inspiration for your own wastewater projects

This white paper features lessons learned from different Danish stakeholders within wastewater treatment. It is meant to serve as a tool for inspiration for reaping the benefits of using wastewater as a resource.

Partners featured in this publication



Ramboll is a leading multidisciplinary independent consultancy company Our 1,500 experts in energy provide our customers with cost-effective energy and climate solutions that meet today’s standards. We are among the leading consultants in the world within important energy, climate mitigation and climate adaption services: •Sustainable development of liveable cities •Least cost energy planning and strategies •District heating and cooling •Combined heat and power •Heat pumps •Waste to energy •Large scale solar water heating •Thermal storage tanks and storage pits •Wind farm infrastructure on and off shore •Power grids •Integrated smart energy system •Climate strategies •Waste management •Biogas •Exploration of oil and gas •Natural gas transmission and distribution •Natural gas storage Our multidisciplinary approach also includes other renewable sources, hydro power, geothermal energy, energy efficiency in building and industry and low energy buildings. Furthermore, Ramboll’s experts address global water and climate challenges by working across the water cycle from water resources and supply, processing and treatment, to sewerage and discharge. Working with municipalities, utilities, and industrial clients we draw on multidisciplinary expertise to create innovative, sustainable and liveable solutions for our customers and society. Our more than 700 water consultants – mainly engineers, hydraulic specialists, water consultants and landscape architects, but also economists, legal advisors and management consultants – work with water projects on a global scale with more than 50 years of proven experience. Discover more in this video about Ramboll's global water practice. To learn more about Urban Energy Solutions, see Rambolls blog