The environmental benefits of Oceanhamnen after 6 years in operation
After six years in operation, Oceanhamnen has established itself as one of Europe's most interesting examples of how source-separated wastewater can contribute to more circular urban development. In this district, blackwater, greywater, and food waste are collected separately to enable the recycling of water, nutrients, and energy.
For four decades, our people have developed trusted and eco-efficient sanitation solutions used around the world. We believe technology can make a positive difference – and that dedication and competence are key to making it happen.
Lars-Inge Persson, the chairperson of Brf Ophelias Brygga (and a resident in the area), has monitored the development since people moved in. For him, the experiences demonstrate that the technology works not only in theory but also in everyday life. At the same time, the project has provided valuable insights into operation, maintenance, and how future sustainable water systems can be developed.
Lars-Inge points out that water source separation is a natural progression, just as society has long been sorting waste. For him, the key is that greywater, blackwater, and food waste are managed separately to be recycled and create new resources.
The three-pipe system and vacuum technology are central components in the sustainability concept of Oceanhamnen, where even wastewater is utilised as a resource.
Experiences of the system in practice
During the first years, there were some initial issues, including operational downtimes in the building's vacuum system. Deposits in certain pipes are now being addressed. Procedures for operation and maintenance needed improvements. Through feedback from experiences, the knowledge of system design has been optimised.
According to Lars-Inge, the situation has significantly improved. Most problems are now identified and are managed through planned maintenance, monitoring, and technical improvements. Unplanned stoppages are now rare, and the stoppages that have occurred over the past year have mainly been caused by incorrect use, such as objects entering the system.
He believes that the most important remaining issue is to complete long-term operation and maintenance routines to ensure stable functionality in future installations.
Environmental benefits and resource efficiency
The greatest benefit of the system, according to Lars Inge, is resource efficiency.
- The association has remarkably low water usage, crucial when water becomes an increasingly valuable resource! Lars-Inge states.
He particularly highlights:
- Significantly lower water consumption, around 80 liters per resident per day (compared to the national average of 130 liters)
- Potential to recover phosphorus and nitrogen from wastewater
- Biogas production from blackwater and food waste
- Ability to reuse greywater
- Reduced load on traditional water and sewage systems
He emphasizes that a vacuum toilet uses approximately 0.6 liters of water per flush, which is a dramatic decrease compared to traditional toilets. According to him, this is one of the most tangible and easily understandable advantages of the system.
With the three fractions that Ophelia's Pier sends to the local treatment plant RecoLab, optimal resource recovery can create value. For instance, phosphorus and nitrogen in the dry matter can be extracted, approximately 60% more biogas can be produced, and greywater can be treated to drinking water quality in a more efficient process. At Oceanhamnsbadet, the pools will be filled with the treated greywater.
The challenge is that old laws and regulations need to keep up with advancements, they need updating.
User experience
Residents generally do not perceive the vacuum toilet as an issue. The flushing sound is sometimes noted, but it is not considered disruptive in everyday life.
Visitors often respond positively when they learn about the minimal water usage and the system's role in the circular process. Many also find the food waste disposers to be a valued part of the solution.
Summary conclusion
Lars Inge's overall message is that Oceanhamnen has demonstrated the concept's effectiveness. The project has encountered teething problems, but these are viewed as natural for a new technology. The major lessons focus on operation, maintenance, education, and organisation rather than the technology itself.
He views vacuum systems, source-separated wastewater, and resource recovery as vital for the sustainable urban development of the future and believes the experiences from Oceanhamnen should be used to enhance and propagate the concept in future projects.