by Alex Røge Hermansen

AAU takes care of water quality by a total ban on the use of pesticides on university land. At the same time, research is being conducted into how we can maintain the high quality of Danish groundwater. In Denmark, we drink our groundwater, but many years of pesticide use threaten our clean drinking water. In a new study, a team of researchers from Aalborg University has shown that ultraviolet light, without direct contact with the water or the addition of chemicals, can be used to remove pesticides from our drinking water. Read more about the study here.

As part of its environmental, climate and sustainability efforts, Aalborg University prioritises avoiding pollution and emissions of chemical, organic and nutrients to the marine environment, thereby contributing to securing SDG 14 Marine Life, but certainly also SDG6 on clean water and sanitation. In addition, wastewater treatment contributes to ensuring sustainable energy supply (SDG7) and climate action (SDG13).

Typically, sewer systems are divided into rain and wastewater, as there is a very large difference between the degree of pollution and the volumes of water to be handled.

Rainwater that falls on roof surfaces, roads, paths and parking areas, etc. is generally considered only lightly or completely uncontaminated water that seeps directly or is handled in separate rainwater systems. Any undesirable substances, e.g. oil films and solid particles, such as paper and plastic waste residues, plant material, sand and rubber residues, etc., are retained in rainwater basins, where they are settled and later collected and brought to recycling/landfill as part of the operation. From the rainwater basins, rainwater is discharged in a controlled manner via streams to the sea, without compromising legislation and environmental requirements to ensure good ecological status in the wetlands. Read more about stormwater management below.

Wastewater from the university's many teaching, office and research buildings is treated before it can enter the natural cycle. All wastewater at Aalborg University is routed in closed pipe systems to treatment plants, where the wastewater is treated mechanically, biologically and chemically, thereby removing unwanted waste (e.g. hygiene items) as well as waterborne nutrients, heavy metals and chemicals that may otherwise be harmful to the aquatic environment.

Wastewater

Wastewater from campus Aalborg is treated at Aalborg Utility's wastewater treatment plant. At Campus Esbjerg, the wastewater is treated by DIN Forsyning and at Campus Copenhagen, the wastewater is treated by Biofos A/S. Before the wastewater leaves the university's premises, it is ensured locally that unwanted chemicals and substances are separated from, for example, via oil and fat separators, acid neutralizers, etc. that the university's staff and external partners continuously service.

Through ongoing wastewater planning, mapping and sampling, it is ensured that the discharge of chemical substances, heavy metals, etc. strictly complies with the limit values set in the legislation and in the wastewater permit imposed by the university from the public environmental authorities. If the limit values are exceeded, investigations into sources of pollution shall be carried out immediately so that the activity can be brought into conformity with the waste water permit.

When the wastewater has been through a multitude of treatment processes at a treatment plant, the completely clean water is now discharged directly into the sea. The retained residue from the treatment processes is sewage sludge, which can be used, among other things, for the production of biogas that becomes electricity or district heating. Dried sludge is used as a source of raw materials and energy in industry, e.g. in cement production, while certain nutrients can be used in agricultural production. Wastewater is therefore perceived as a resource that contributes to the green transition, and several treatment plants are CO2 neutral.

Rainwater:

As a result of climate change, rainwater that falls in large quantities poses an increasing threat to buildings, facilities, biodiversity and to the aquatic environment in particular. Optimally, precipitation seeps directly down where it falls, but with increasing urbanization, there is also a need for water flowing from built-up areas and roads, etc. to be handled and led via streams into the sea.

In order for the natural watercourses to keep up, it is important through planning and climate measures to delay the flow of water through the rainwater systems, both for capacity reasons to avoid flooding, but also to ensure that the water speed remains sufficiently low that unwanted particles and nutrients have time to settle and are retained in rainwater basins so that it is not led into the marine environment,  from which it cannot be removed.

In order to minimize the discharge of rainwater to streams and streams and to protect the aquatic environment against overload from extreme rain events, Aalborg University continuously seeks to incorporate principles for local management of rainwater (LAR) in the planning, where the water is sought to be delayed or retained, seeped and absorbed by plants, rather than discharged directly into streams and the sea with the risk of excessive nutrient load on the aquatic environment as a result.

At the main campus in Aalborg East, a significant reconstruction of the existing stormwater system has been carried out in recent years, so that it is now climate-proof to cope with a 100-year rain event. The project for converting the lake and canal system into a LAR system has been developed in collaboration with the Danish Building and Property Agency, Aalborg Municipality and the housing association Himmerland. The ambition of the project has been to ensure clear water in the lakes, better water quality in the recipients and a significant boost of the area's biodiversity and recreational value through the planting of a meandering stream with wild shrubs, trees and flower meadow/wild on purpose. Read more about the project here.

The majority of the university's parking spaces are established with permeable grass reinforcement surfaces, so that rain can seep through the pavement rather than drain to the rainwater systems. At the university's playing field, a system has also been ensured where drainage water from the playing field is collected in a tank from which gardeners can tap water in the summer for irrigation of flowers and trees, so that drinking water is not used for this. The university wishes to ensure similar solutions in future buildings in order to become self-sufficient in water for the green areas and parks. In 2022, the rainwater collected covered 100% of the irrigation needs for outdoor areas – a total of around 50,000 litres.

In collaboration with the other initiators of the restoration project for the Lake and Canal Plant, Aalborg University has established a Rainwater Guild, which will be responsible for operation and maintenance of the area, including ensuring the continued hydraulic function of the plant, biodiversity and a clean aquatic environment. The Guild's board, chaired by Aalborg University, has entered into an agreement with an external gardener/contractor to ensure the maintenance of the facility for the benefit of both the university's many daily users and the local residents in the area, who have been given a fantastic natural area as their closest neighbour.