EN PROGNOSMODELL FÖR MÄNGDEN LÖST ORGANISKT MATERIAL I VÄNERN / A Forecast Model for Soluble Organic Matter in Lake Vänern
The loading of organic matter to Vänern peaked during the mid-1960’s. Restructing and improvements of treatment procedures within the paper and pulp industries have resulted in a decrease which later resulted in a reduction of the permanganate numbers and an increase of Secchi depth. In order to evaluate later developments, the changes of KMn04-numbers have been calculated for various degrees of loading using a time simulating technique. Results show that KMnO4-numbers will level off at about 19 mg KMnO4/l if the present industrial loading (ca. 200 000 ton) continues. If this loading is decreased by 50 %, KMn04-consumption should reach a level of about 16 mg KMn04/l by the year 2000. Secchi depth will increase from 5.4 to 6.2 m by the year 2000.