Why the Oxidation Ditch disappeared in Sweden? / Varför försvann Ringkanalerna i Sverige?
The Oxidation Ditch has played a very important role as a foregoer for a number of low load activated sludge systems in the water industry. Today different models are found around the world. The ditch system developed in the late 1950’s originated in the Netherlands. Early Swedish research and development work took place in the 1960’s. However in contrast to other countries the focus on the Oxidation Ditch was abandoned. This paper gives a very brief presentation of the ditch system and discusses a number of reasons why the Oxidation Ditch with very few exceptions is not found in Sweden today.