Hungarian Organisations undertake numerous mitigation activities to protect Danube

On the 4th of October 2010, due to the levee breach of the sludge reservoir of the Hungarian Aluminium Ltd. (MAL Ltd.) - located in Hungary around 150 km south-west of Budapest in the surrounding area of Ajka town - the spilled red sludge caused significant environmental damage. The highly alkaline sludge entered from the reservoir into the Torna creek through which the pollution reached the Marcal River.

Red mud is a by-product of the bauxite refining process; a refinery produces about the same amount of red mud as it does aluminium. About 40%-45% of the waste is iron-oxide, which gives it the red colour. The mud also contains other elements such as titanium, aluminium, and soda in addition to heavy metals such as lead, cadmium and chromium. The soda is the cause of the elevated pH which is typically in the 12-13 range. The heavy metals level are not higher than the heavy metal concentration commonly observed in the ground. Red mud is not considered as “hazardous waste” in the European Waste Catalogue of the European Commission. There are two major threats stemming from the spill of the red mud into the environment – the acute effect of the elevated pH and acute and/or chronic effects by heavy metals.

The Hungarian organizations of the mitigating activities carried out the localization and neutralization of the pollutants in the river Marcal:

Water quality monitoring points were selected in the Torna creek, Marcal river, Rába river, Mosoni-Duna Danube branch and Danube river where the water quality parameters are monitored continuously.
The feeding sites of the applied dispersed materials were fixed. Supply of the needed additive materials is continuous.
The potentially dangerous pollutants were localized by sedimentation in low flow areas with the help of construction 6 underwater dikes and operation of the Marcal barrage.
Disaster was avoided downstream of the Marcal river, the pollutants were retained. The continuous operation of the established neutralization system is ensured. In order to control potential further pollution, the operation of the implemented system will be continued while the potential danger of pollution exists.
Stabilization of the dam of the sludge reservoir and collection of pollutant material close to the site of accident are current activities. Hungary started planning the remediation of the damaged areas

- ICPDR (International Protection of the Danube River)