5 solutions to utilise wastewater as a resource

The perspective on wastewater is shifting from a waste byproduct to a valuable asset. We have gathered five cases proving that wastewater can be a key contributor to both environmental and economic sustainability.

Photo credit: Biofos / Luftfoto Danmark ApS

By State of Green | [email protected]

13 August 2024

Unlocking the potential of wastewater

This white paper features a series of best practice examples of wastewater treatment – both centralised and decentralised. Discover the white paper and learn how to use wastewater as a resource while protecting people and ecosystems.

Discover the white paper

Innovative solutions can turn wastewater from a mere byproduct into a valuable resource.

The Danish water sector showcases a holistic approach to water management, setting a global example for optimising energy consumption and addressing emission challenges while maximising resource recovery. From phosphorus recovery to biogas production, Denmark demonstrates the potential of wastewater as a source of renewable energy and critical materials.

We have collected five cases exemplifying this approach, where advanced technologies and strategic collaborations are not only addressing environmental challenges but also creating new opportunities for energy production, resource recovery, and sustainable development. These cases showcase how Danish expertise is setting new standards in wastewater management, highlighting the potential for wastewater to contribute positively to both the environment and the economy.

1. Centralizing wastewater treatment in Assens Municipality

Assens Municipality faced the challenge of outdated and space-constrained wastewater treatment facilities that couldn’t meet future demands. To address this, a new centralized WWTP was established, replacing eight smaller plants, and integrating innovative technology to operate as an energy producer. This facility not only enhances environmental protection and operational efficiency but is also designed to be CO2-neutral by 2029, supporting both urban development and sustainability goals.

The new wastewater treatment plant, located in a dedicated utility park, consolidates the functions of eight smaller plants, creating a future-ready facility with a capacity of 100,000 person equivalents (P.E.), expandable to 150,000 P.E. The integration of innovative technology enables the plant to operate as an energy producer. Additionally, a biogas plant will be established on-site to maximize energy recovery from industrial wastewater and sludge, further reducing environmental impact.

Solution providers: COWI, Assens Utility, Envidan A/S, NCC A/S, Jacobsen & Bindkilde A/S, & Cubo A/S

Discover the case: From eight to one innovative, centralized wastewater treatment plant

2. Tackling PFAS Contamination in Odense’s Landfill Leachate

Photo credit: Ramboll

Odense, the third largest city in Denmark, faced significant PFAS contamination in landfill leachate, a major source of these harmful “forever chemicals” in wastewater. To tackle this, Odense Renovation partnered with utility company VCS Denmark and experts to map PFAS levels and test advanced treatment technologies like foam fractionation and flocculation.

The collaboration revealed that while foam fractionation and flocculation technologies could reduce PFAS concentrations, achieving compliance with environmental standards remains challenging and costly. The project highlighted the need for further refinement of PFAS removal technologies and established a crucial knowledge base for future investments in PFAS treatment at source.

Solution providers: Ramboll, VCS Denmark, Odense Renovation, ECT2 and Envytech Solution

Discover the case: Leachate PFAS-removal from landfills in Odense

3. Unlocking the hidden value in industrial wastewater

Many companies currently pay wastewater treatment plants to handle their industrial wastewater, missing out on the valuable resources these streams contain, such as heat energy and product residues. The challenge lies in the lack of awareness and technology to exploit these resources, especially when different water streams are mixed before treatment.

The ReUse project, Denmark’s largest MUDP initiative, is helping companies unlock the hidden value in their industrial wastewater by mapping and recovering valuable resources like heat and product residues. With a DKK 90 million investment, the project aims to implement full-scale solutions at three companies, where significant progress has already been made in recycling water and energy. The initiative underscores the potential for reducing waste and enhancing sustainability in industrial processes.

Solution providers: DTI – Danish Technological Institute, Aquarden, CP Kelco, Hartmann A/S, Nopa Nordic, Tetra Pak Filtration, Silhorko-Eurowater, Viegand Maagøe & Q-Interline

Discover the case: ReUse – Recycling of resources from industrial waste streams

4. Digital transformation of wastewater treatment in Milan

Photo credit: DHI

At the Bresso-Niguarda wastewater treatment plant near Milan, Gruppo CAP sought to optimise operations through real-time data and advanced process modelling as part of a broader digitalisation strategy.

Gruppo CAP implemented DHI’s TwinPlant at the Bresso-Niguarda wastewater treatment plant in Milan to enhance operational efficiency through real-time data and advanced process modelling. Using DHI’s MIKE OPERATIONS platform, the system integrates online sensors and models, enabling operators to optimise energy use and resource recovery in a virtual environment. The result has been improved plant performance, with a user-friendly dashboard helping to identify and implement optimal operational strategies.

Solution providers: DHI and Grupo CAP

Discover the case: A digital twin to support wastewater treatment operations

5. Reducing nitrous oxide emissions at Flensburg’s wastewater treatment plant

Photo credit: Andreas Große

In 2022, the TBZ Flensburg wastewater treatment plant aimed to reduce nitrous oxide (N2O) emissions, a potent greenhouse gas, as part of its climate neutrality goal. The challenge was to identify the primary sources of N2O within their nitrogen degradation processes.

Using the Unisense Environment N2O Wastewater System, they pinpointed two key emission sources, enabling the development of targeted mitigation strategies. This data will be crucial for future CO2 equivalent accounting and for optimising process control, helping the plant move closer to climate neutrality by implementing targeted countermeasures and long-term monitoring.

Solution providers: Unisense Environment

Discover the case: Identifying N2O in Flensburg’s wastewater treatment