Nordic Algae Research for Passive Wastewater Treatment in the Mining Industry (NARMIN)

Project duration: 2024-10-28 until 2025-06-30

Background

One of the biggest environmental challenges facing the global mining industry is its wastewater, which is full of heavy metals. Heavy metals cannot break down and therefore accumulate in the food chain. The water quality in adjacent lakes depends on the ore type, the catchment area’s geology, catchment interactions, and water treatment processes.

Hosiojärvi is a lake in northern Sweden near Kiruna, close to the Finnish border. Lake Hosiojärvi is located near the graphite deposit in the Vittangi area and has shown elevated levels of several heavy metals, although exploration and graphite extraction have yet to begin. We previously demonstrated that microalgae have great potential to purify water from heavy metals. Algae have been shown to effectively treat various types of wastewaters by recycling nutrients, converting CO2 into biomass, and removing contaminants from the water column. The water in the Nordic lake Hosiojärvi is nutrient-poor, so only a few algae grow naturally in the lake. The addition of nutrients increases algal biomass, and a recent study showed that adding wood ash has the same potential. Increased algal growth immobilizes metals in the sediment through deposition, reducing water toxicity in, for example, open-pit lakes.

We will test the potential of microalgae, which naturally grow in Lake Hosiojärvi, along with already-tested Nordic species, to purify the lake's water from heavy metals. We will 1) isolate natural microalgae, 2) compare their cleaning potential with known strains, 3) cultivate them in natural lake water, and 4) build a mesocosm to simulate purification in the lake.

Financing and partners

This project is financed with the support of Vinnova Swedish Metals & Minerals (2024-02669).

Luleå University of Technology (project coordination)

Umeå University

Talga