Aquascope Facts
We should try to avoid cultivating only one type of crop and after harvesting leaving the land fallow during the autumn and winter. If for example, another type crop was sown during the autumn, the straw from it can for example be used to produce methane gas, it can even be mixed with liquid manure to reduce nitrogen seepage from the soil.
    A good water basin is also another important measure that can reduce the leakage of nitrogen and phosphorus compounds. A water basin is an area where the land is drained of water and the system that transports it to the sea (i.e. brooks, rivers and lakes). If the water is transported over a long and open route, it is possible for the excess nitrogen and phosphorus to be used up by natural Biological processes before it reaches the sea. To try and create a good water basin, the authorities in Schleswig-Holstein in Germany introduced regulations in 1989 prohibiting the use of artificiel fertilizers within 10 metres from a watercourse.

Measures in sewage treatment

It is important that all households, industries and farms are connected to some form sewage treatment facility. Unfortunately this is not the case in some of the countries surrounding Sweden. In Sweden for example, about 98% of the households are connected to a sewage plant that uses chemical felling as part of the treatment process. This is not the case amongst some states around the Baltic. In certain former eastern states, untreated sewage is discharged directly into the rivers that flow into the Baltic. It is important that more affluent states contribute both economically and technically to reduce these pressures on the sea.
    In a sewge plant, treatment is a process involving several stages. In one stage, nitrogen cleaning is a priority. With the use of bacteria to bind the nitrogen, the content is drastically decreased in the water that is afterwards discharged into the sea. With modern techniques, the nitrogen content can be reduced by up 70-80%. Unfortunately, the reduction of nitrogen content is a rather complicated proceedure and not used by many of the states bordering the Baltic. Algae is also used to bind nitrogen, whereafter it is strained from the water.
    Nitrogen cleaning efforts have shown good results. From certain sewage plants, a reduction of 15% was achieved from between 1985 and 1995. Today, Swedish sewage plants release about 17 500 tons of nitrogen annually into the environment. With the currently planned construction of about 70 sewage plants in Swedish coastal areas, it is expected that the above discharge of nitrogen will be reduced by an additional 4 500 tons annually!
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A splendid outing ?
Problems and expectations
”It was better before"
Seawater and soluble salts
The sea moves
Coastal waters are close to us
What is eutrofication?
Sources of over-fertilization
How the open masses of water are effected
How shallow bays are effected
What can we do?
Alga harvest

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Bo Johannesson | Martin Larsvik | Lars-Ove Loo | Helena Samuelsson