The small lake Trummen is in the city of Vaxjo in the south Swedish upland. The lake was oligotrophic till the beginning of this century, but the increase of population, domestic sewage and industrial waste water resulted in progressive eutrophication. The intense bloom of blue-green algae was observed annually in the lake. Expanding growth of reeds and killing of fish due to oxygen deficiency proceeded. In 1958 municipal sewerage and industrial waste water were diverted, but without expected effects. A restoration research project was thereafter planned by scientists from the Institute of Limnology of Lund University in cooperation with the Vaxjo authorities.

Suction dredging, the main part of the restoration project, was carried out in 1970-1971. Approximately 60 cm of FeS-rich black and brown mud was removed from the lake bottom and transferred to specially prepared depositing ponds through pipelines. The depositing ponds covered a total area of 18.5 ha with surrounding embankments about 4.8 km in total length. The total cost, including for preliminary survey, dredging, embankment and other treatments, amounted to 2,575,000 Sw. Kr.

The Trummen project drew world-wide attention, being the first successful example of large-scale restoration of a lake where sediment pumping was employed. The lake is being visited by many administrators and scientists from various parts of the world who are interested in the study of this excellent achievement in applied limnology.