21.04.2015

Gypsum treatment of fields would save the Archipelago Sea

New method could realise almost half of Finland’s phosphorus discharge reduction target

The article has been first published in Helsingin Sanomat Vieraskynä (Guest columnist) on April 18, 2015  

In the past few years, we have managed to reduce the phosphorus discharges that cause eutrophication in the Gulf of Finland by as much as 60%. This achievement has been made possible through improving the efficiency of phosphorus removal from the wastewaters of St. Petersburg, renewing the city’s treatment plants and sewage systems, and by reducing the discharges from a Russian fertilizer factory to the River Luga. Results are visible particularly in the eastern part of the Gulf of Finland, which was record-breakingly clear last summer. This concrete work aiming at improving wastewater treatment must continue in Russia, and also in the populous cities of Poland. When we focus on the greatest point load sources, we can improve the status of the Baltic Sea quite fast.

Up to now, we have not been able to find a method for making fast and large-scale cuts into discharges from the agricultural sector. The problem has been evident particularly in the Archipelago Sea, where loads mainly originate in discharges from Finnish agriculture.
During last summer’s heatwave, the duality of the marine areas was clearly visible: in eastern Gulf of Finland, we rejoiced as the waters were crystal clear, but the Archipelago Sea was covered with a smelly gruel of blue-green algae.

However, there is now new hope for the Archipelago Sea. After many years of experiments, the researchers of the University of Helsinki and the Finnish Environment Institute have confirmed that a ground-breaking new method of treating fields with gypsum may curb discharges from agriculture significantly, particularly in southern Finland. By spreading gypsum on farm fields, Finland could reach almost half of the 330-tonne phosphorus discharge reduction target, set for Finland by the Baltic Marine Environment Protection Commission HELCOM.

This is not the first time gypsum is used for soil improvement, but using the substance in water protection is a novelty. The research conducted in Nurmijärvi discovered that gypsum reduces the drift of soil-bound phosphorus to waterways in the runoff area by 60%, and reduces the discharges of dissolved phosphorus by 30%. Gypsum also significantly reduces the volumes of clay and char that drift from the fields, making the waterways discernibly clearer.

Gypsum is easy to spread with liming machinery during autumn ploughing. Gypsum dissolves in the soil solution, and does not harden the land. The method is based on improving the aggregate structure of the soil and will not have a negative effect on crops, as plants can utilise the phosphorus retained in the fields.The gypsum treatment of fields could be a means of reducing, with reasonable costs, the annual phosphorus load entering the Archipelago Sea by as much as 30%, or 100 tonnes In the Gulf of Finland, the reduction would be at least 50 tonnes. Such a significant cut in discharges would reduce the volume of algae blooms discernibly.

Because of the sulphate contained in gypsum, the treatment is not applicable in lake regions. The clay fields of the Archipelago Sea coastline, on the other hand, are a safe location for gypsum treatment, as the sea naturally contains sulphate. Waste gypsum, a side product of the fertilizer industry, is stored in Finland in large quantities in Siilinjärvi, for example. Reusing waste gypsum in water protection would be a wise and cost-efficient contribution to a circular economy.

The cost of treating applicable fields in southern Finland, and achieving a reduction of approximately 150 tonnes of phosphorus, would be €55 million. Research results indicate that gypsum is active in the soil of the fields for at least five years, so the operation would only cost €11 million per year. This is a minor sum when compared to, for example, environmental aid to the farming industry, which is paid out in the amount of €200 million annually.

This cost-efficient and effective method could save the Archipelago Sea, which is currently in a sad state. We should seize this opportunity without delay.

Next, we should establish a major pilot project in cooperation with universities and research institutions.  The project would make gypsum treatment known amongst farmers and the public at large. Moreover, we could survey all of southern Finland to identify the areas where the method will be applied. We could at the same time assess how to include gypsum treatment in the environmental aid paid to the farming industry.

The pilot project, implemented by the department of economics of the University of Helsinki and the Finnish Environment Institute, is already being prepared under the leadership of professor Markku Ollikainen. Funding for the project has been applied for from the resources reserved for the protection of the Baltic Sea and managed by the Ministry of the Environment and the Ministry of Agriculture and Forestry.

A project of such great significance should receive public support.

Juha Nurminen  
The author is a maritime counsellor and the chairman of the board of the John Nurminen Foundation.

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