RecoLab: World's largest source-separated sanitation plant in Sweden

NX Filtration delivered its hollow fiber nanofiltration membrane modules for the removal of micropollutants and nutrients to the RecoLab project to efficiently recycle biologically treated wastewater in Helsingborg, Sweden.

“WASTEWATER PROJECT OF THE YEAR ” by GWI Global Water Awards 2022.

The customers query
The city of Helsingborg runs a full scale energy-efficient, circular sanitation process that source-separates blackwater, greywater and food waste through separate pipelines to recover nutrients, produce biogas and recycle wastewater to drinking water quality. The objective is to recover as much water as possible.

The city of Helsingborg expects to further expand the water recycling plant in the coming 3-5 years. In this period the re-use process for the high quality recovered water will be further finetuned within their own premisses called Recolab. This full scale plant has demonstrated to be an important inspiration for other nutrient, energy and water re-use projects, in- and outside of Sweden.
Our approach
We applied our dNF40 nanofiltration membrane modules s for the removal of micropollutants (including pharmaceuticals, oestrogens, microplastics, antibiotics and personal care products) from wastewater effluent, after conventional activated sludge treatment, to produce water of drinking water quality. Since the objective is to recover as much water as possible, the dNF concentrate is treated with ozone to break down the micropollutants, and in turn this stream is returned for biological treatment.

For this project, NX Filtration is collaborating with DeSaH (process design) and Jotem (membrane filtration skid). The concept vision was developed by NSVA in Helsingborg. Wetsus, the European knowledge centre for sustainable water technology, is closely studying the operation of the plant in order to help apply this concept with accumulated knowledge around the globe.

This is how the water recycling plant works
The facility manages and sorts the sewage from Oceanhamnen area, Helsingborg. The concept is also called “Three pipes out”. This means that black water (toilet water), gray water (kitchen, shower, and dishwasher water) and food waste come in separate batches to the sewage treatment plant. Just as source-sorted household waste enables better recycling of e.g. paper, metal and glass, “Three pipes out” enables better recycling of important resources in black and grey water and food waste, namely nitrogen, phosphorus and… clean water!

18 process steps

1 - Shower and wash water
2 - Biological cleaning
3 - Chemical precipitation
4 - Drum filter

5 - Membrane filter
The water is pressed through a hollow fiber nanofiltration membrane (dNF40). All organic molecules, such as drug residues, are held back by the membranes. The water coming out of the membranes is of drinking water quality.

6 - Ozonation
7 - Heat exchanger
8 - Toilet water
9 - Biogas is formed in digesters
10 - Certified fertilizer
11 - Struvite extraction
12 - Ammonia is separated
13 - Waste water is purified
14 - Recycled nitrogen
15 - Food waste
16 - Pasteurization tanks
17 - Liquid phase from digester
18 - Recycled phosphorus


For more detailed information about the process and Recolab, click here.


RecoLab is a development facility located next to the Öresundsverket, Helsingborg's sewage treatment plant. The facility is designed for 2000 pe.


The development facility began commissioning in May 2021.

The results
This project sets the standard for sustainable, circular water and waste management at a local level. Biologically treated municipal wastewater passes through NX Filtration's direct nanofiltration membranes that removes micropollutants and nutrients. The product water will be directed to a nearby swimming pool.

The project is operating stable. The dNF40 membrane modules of NX Filtration have proven to be very reliable in producing high quality water. The total system is producing biogas and fertiliser, and recycling 80% of greywater. The project contributes to a lower carbon footprint, increased renewable energy output, nutrient and water re-use. The full scale Recolab plant also provides a standard for a collaborative approach to domestic waste management between water, wastewater and energy utilities, that maximises environmental sustainability.

Download product specification sheets


Robert Gerard
Water and wastewater expert

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