Defence of PhD thesis on wastewater treatment

A PhD study at University of Oulu has been performed by Hanna Virpiranta as part of the Kolarctic CBC SEESIMA project. The topic is “Development of biological treatment for sulfate- and metals-containing cold mining-impacted waters”. Hanna will now defend the thesis on the 24th February 2023 at the Arina auditorium (TA105), Linnanmaa, Oulu.

The PhD study developed a biological treatment process suitable for cold regions, using sulfate-reducing bacteria. The sulfate-reducing bacteria were obtained from a sediment sample from the boreal region and were adapted to the cold conditions. Initially succinate was used as the carbon source, but the use of different lower-cost carbon sources was also studied (such as sewage sludge, peat and whey), as well as synthetic and actual mine wastewaters.

After initial batch experiments the studied continued with the use of a continuous up-flow biofilm reactor, the layout of which is depicted in the diagram above (from Virpiranta et al 2022). The sulfate-reducing bacteria consortium was found to be able to grow at temperatures as low as 6 degC. At a temperature of 11,7 degC the rate of removal of sulfate was 4500 mg/( and 87% of the original sulfate was removed. The reduction of sulfate formed hydrogen sulphide that caused the precipitation of most of the metals present in the wastewater. A further application of the sulfate-reducing bacteria was also investigated for the bioregeneration of ion exchange resin used for further sulphate removal from the waterwater. In lab-scale column experiments the resin capacity was almost completely restored.

The results of this study provide valuable information about the use of biological sulfate reduction for the treatment of Mine-impacted waters in cold regions, and the combination of sulphate reduction and ion exchange as treatment methods.

Joint Finnish-Russian wastewater study published

In the SEESIMA project collaboration was established between researchers at University of Oulu and the Kola Science Centre to study the treatment of mining wastewater. Absorbents produced from natural materials such as peat were modified to improve their performance, and tested for their efficiency at removing different heavy metals and sulphate under different conditions, such as acidity.

The work has recently been reported in a joint article: “Removal of sulfate and metals from wastewater of a mining enterprise by a dual sorbent system: a case study”. The authors were Eugenia Krasavtseva, Harshita Gogoi, Antion Svetlov, Tiina Leiviskä and Dmitriy Makarov.

The graph above shows the reduction in the strontium concentration achieved by the brucite (magnesium hydroxide) sorbent at different pre-treatment temperatures and ph levels. Before using the brucite sorbent the wastewater was treated with a modified peat sorbent to remove sulfate. The graph above shows a better removal efficiency at high pH, underlining the advantage of firstly removing sulfate in the dual-sorbent system. The article can be viewed and downloaded at the Mine Water and the Environment Journal.

Defence of Vitalis Chipakwe’s PhD thesis

Vitalis Chipakwe has been working on a PhD study partly funded by the Kolarctic CBC SEESIMA project. The topic is “Application of Chemical Additives in Mineral Beneficiation – Implications on Grinding and Flotation”. Vitalis has now prepared the thesis and will be defending the thesis on the 21st February 2023 from 1000 to 1200, at Luleå Technical University, room F1031. The defence can also be followed online on Zoom at this link.

The PhD was concerned with investigating improvements to the size reduction process of mineral processing, which consume large amounts of energy and are necessary to liberate the valuable components from the rest of the ore. The size reduction also traditionally uses large amounts of water, which then requires waste water treatment.

The initial part of Vitalis’ study was concerned with the dry grinding process, that uses less water than traditional wet grinding. Dry grinding can reduce the water consumption, but also requires more energy than wet grinding. Additives that allow a reduction of the energy consumption were investigated, including natural polymer additives as an alternative to synthetic polymers.

The study then continued by studying the effect of the additives on the downstream separation process (such as flotation), as well as the effect of the additives on the energy consumption of traditional wet grinding.

Vitalis is now working as a Development Engineer at Boliden in Skellefteå.

Vanadium recovery from spent iron sorbent

Collaboration between the Kolarctic CBC “SEESIMA” project and the Interreg Nord “VanProd” project has resulted in an article published in the Resources, Conservation and Recycling Journal. The article is entitled “Vanadium recovery from spent iron sorbent used for the treatment of mining influenced water” with Tiina Leiviskä from the University of Oulu as a co-author.

Flow diagram of the Vanadium recovery process

When mining influenced wastewater that contains vanadium is cleaned with an iron sorbent the sorbent eventually becomes saturated with vanadium and needs to be replaced. This study examined how the sorbent can be treated to recover the vanadium and regenerate the sorbent to allow it to be used again. The treatment was a two-step process involving regeneration of the sorbent with sodium hydoxide, followed by precipitation of the vanadium as calcium vanadate. Vanadium is an important additive in steelmaking, to improve the hardness and wear resistance.

Nussir copper mine information meeting

Nussir A.S. is holding a public meeting (1800 – 1930 CEST 28 June 2021) to present information about the status of the process relating to the opening of the copper mine at Repparfjord in Finnmark, Northern Norway.

Due to COVID restrictions the number of places for physical attendance is limited, but the meeting is broadcast over

  • CEO Øystein Rushfeldt will give the latest update on the plans for opening the mine.
  • Project Manager Odd Henning Grove will give an update on the progress on the industrial site.
  • Anstein Amundsen will present information about the sea deposition of tailings.

SEESIMA project profiled on Kolarctic Programme webpage

As part of the regular profiling of projects financed by the EU Kolarctic CBC Programme, the Kolarctic Programme webpage included an article describing results from the SEESIMA project, published on 12th February 2021. This article attempts to give a “Popular Science” summary, with a focus on the possibilities to reduce the energy consumption of processes to reduce the size of minerals.

Pictured at right is one of the grinders at the Khibny PhosAgro mineral processing plant.

See the article here, and in Russian language here.

Positive results obtained from nitrate removal process

A European EIT Raw Materials project, ‘NITREM‘, has achieved positive results from a pilot scale implementation at LKAB’s Kiruna mine and is planned to be scaled up to full-scale. Nitrate concentrations of around 70 mg/litre in the leachate from waste rock piles was reduced to less than 10 mg/litre (an efficiency of 77%) after passing through a bioreactor. Nitrate is formed from the residual of ammonium nitrate-based explosives used in mining, and causes unwanted growth of algae leading to autrophication of waterways.

The bioreactor is a passive design, requiring little intervention. An oblong pit is constructed, the walls sealed with a geomembrane, and filled with wood chips and a dose of activated sewage sludge containing nitrogen-reducing bacteria. The bioreactor is covered an operates under anaerobic (oxygen-free) conditions. The bacteria utilise carbon from the wood chips to transform the nitrate to nitrogen gas, while the leachate flows through the reactor.A trial during 2019 recorded an average nitrate removal efficency of 77% with input nitrate contents of 61 – 87 mg/litre. During the operating period the average temperature was 3 °C, confirming that the microbial process is suited for use in cold climate conditions.

The process is proposed to be scaled up and implemented at further mining sites to reduce the impact on the environment. Further details are available at the NITREM project webpage. The project consortium consists of Uppsala University, WSP Sverige AB, Cedervall Arkitekter, Agencia Estatal Consejo Superior de Investigaciones Centificas, Boliden Mineral, LKAB, LTU Business and the Swedish University of Agricultural Sciences.

Schematic diagram of the NITREM nitrate biorector system
NITREM nitrate removal process, from

Passive wastewater treatment systems have been widely reported for the reduction of heavy metals, a review is given here. These results that the technology is also suitable for reduction of anions such as nitrate in the wastewater.

Call for papers

A Call for Papers has been issued for a Special Issue of the Journal of Water & Climate Change, with the topic of “Integrated assessment and adaptation to climate change impacts in cold regions”. The Special Issue is related to the 6th IAHR (International Association for Hydro-Environment Engineering and Research) EUROPE Congress – at which Hanna Virpiranta is scheduled to present results from the Kolarctic CBC SEESIMA project. Tiina Leiviskä is one of the Guest Editors of the Special Issue. The submission deadline is 31 March 2021, with expected publication in October 2021.

This Special Issue will cover the following topics:

  • Data sources and acquisitions (e.g. observations, reconstructed, reanalysis, models, remote sensing data).
  • Data calibration, verification and sensitivity analysis.
  • Use of state-of-the-art research methods (e.g. machine learning, hydrological model, climate model simulations).
  • Natural hazards and risk assessment (e.g. urban flooding, snow avalanches, rockfall, landslides, debris flows).
  • Future climatic and hydrological simulations and projections.
  • Changes in the hydrological cycle and heat and energy transfer.
  • Water pollution control and quality management.
  • Innovative wastewater treatment processes, waste management and resource reuse.
  • Impacts of climate change on the total environment.
  • Mitigation and adaptation options (e.g. blue-green solutions, nature-based solutions, and performance assessment, social-economic value and multi-benefits, etc). 
  • Rehabilitation and repairing technologies of structural defects and the use of new materials and new construction methods.
  • Other aspects of hydro-environmental research and innovation topics.

The link to the call for papers is here.

European Cooperation Day in Oulu

The European Union provides financing for cross-border collaboration projects through different regional programmes, such as Kolarctic Cross-Border Cooperation, Interreg Nord and Northern Periphery and Arctic Programmes. To raise the profile of these financing programmes an Exhibition is being held in Oulu between the 21-25 September 2020. More information about the exhibition is available here.

The SEESIMA project is one of 15 EU-funded projects selected for the INNOVATION ACROSS BORDERS Exhibition to illustrate with concrete examples how working with partners in neighbouring regions benefits the research and business environment in each region, as well as it contributes to creating more sustainable communities.

The SEESIMA project is represented by Tiina Leiviskä and Hanna Virpiranta, and the poster presentations will be open for the public to view during business hours of the week 21-25 September. Later the Exhibition will be available as an online display.

Nussir eyeing a possible start in 2020

The planned mine at Repparfjord in Finnmark is edging closer to a start, after a decade of negotiations. The mining licence was received in February 2019 from the Norwegian Ministry for Trade, Industry and Fisheries. Despite some uncertainty created by the corona-virus it is still hoped to start operations in 2020.

The planned Nussir copper mine involves two deposits – at Ulveryggen/Gumppenjunni and Steinfjellet/Nussir. (Picture from Nussir, via High North News)

Planning and financing for the start of operations was underway, but faces some uncertainty regarding the recovery of the financial markets after the corona virus. The Managing Director still hopes to see the mine operations to start in 2020, according to a recent article in High North News.

Nussir plans to extract copper, silver and gold, and also will look into the development of technologies to recover platinum, palladium and tellurium. The delays from the permitting process have allowed the adoption of new technologies, such as the electrification of the mining operations. The demand for copper has also continued to grow, such as for electric vehicles, wind turbines and other forms for renewable energy.