• We chose "cleaning of industri effluent - affactions on Otra" as a theme for our subject. We have chosen to look the lower part of the river, that lies below the industri in Vennesla.
• We have looked at the relations in the river before and after the establishment of the Otra pipe (1995)
• When it comes to pollution and effections, we lay particular stress on the quality of the water , fish, submergred plants and growth.

PRESSURE FACTORS

Today recives Otra pollution from the local outlet water (sewer), discharge from the industry and the pollution that is transported a long distance (sour rainfall).

We have discharges from industry and what consequencen this have for Otra.

• Industridischarges

STATUS

Before Hunsfossmain was built in 1995, it was a clear difference between pH values in Otra, especially Hunsfoss and Vikeland. The ph values could be found in otra, near Vikeland. Now this differance is gone and pH values are rather alike. This has led to improvement for fish, bottom animals and grouth

• Waterquality
• Fish
• Bottom animals
• Growth

INFLUENCE

Discharge from the industry, who are directly lead into the river, gives fishdead, mushroom at the bottom, and sour water.

• Waterquality
• Fish
• Bottom animals
• Growth

RESPONSE

The otrapipe and local factories` cleaningsystems keeps the river free from damaging industrial discharges.

The Otrapipe

• Cleaning systems

    CONCLUTION

After the otrapipes founding in 1995, we can see a positive development relatet to fishdeath, waterquality, growth and bottomanimals in Otra. This shows that todays cleaning of industial discharges is satisfying in relationship to enviromentquestions.

• Reference list.