Controlled Leaking of Sulphuric Acid into the Rhine
When the contents of Tank 7 were pumped into the transport vessel, this affected the stability of the “Waldhof”, which is lying on its side. The foreship shifted down about 20 centimetres towards the scour (the depression in the riverbed) and this led to sagging and torsion (twisting) of the ship’s body. In the area of the tank deck, surface irregularities have appeared. These indicate that there are enormous stress forces within the ship’s body. Any further movement of the vessel may cause the bulkhead and deck to break. This would result in an uncontrolled reaction of sulphuric acid with water. Under these circumstances the salvage enterprise can no longer guarantee the safety of the team working on the capsized vessel.
For this reason the leaders of the operation have decided to let off part of the remaining cargo into the Rhine in a controlled leak.
At the start of this operation in which controlled quantities of sulphuric acid from the motor tank vessel “Waldhof” are being introduced into the Rhine, the monitoring and laboratory vessel “Burgund” recommenced continuous measurements of the waters of the Rhine downstream from the accident site.
The normal pH value in the Rhine is c.8.0 to 8.1.
Approximately two hours after controlled introduction of the acid was begun, a pH value of 6.2 was measured 200 metres downstream from the “Waldhof”. On the left bank 400 metres downstream, no change in the normal Ph value was found. At the same distance downstream Ph values of around 7.1 were found on the right bank, and values of around 7.2 were found in the middle of the river.
This means that the changes in the pH value are better (i.e. smaller) than expected. Thus negative effects on the water ecology are not to be expected. In addition, a helicopter of the Rhineland-Palatinate police, equipped with a thermal imaging camera, flew several times over the area where the acid was being introduced. No change in water temperature from chemical reactions between sulphuric acid and river water could be measured.
A renewed search for the two missing crew members of the “Waldhof” had to be broken off yesterday afternoon without results. Members of the technical task force (TEE) of the Rhineland-Palatinate police were unable to enter the living quarters of the capsized vessel, which are completely wrecked and submerged below the water level.
The tailback of waiting vessels on the Rhine and the Main above Mainz has almost completely dispersed. All vessels on the Main and Rhine now waiting to pass downstream can move forward to the Mainz/Budenheim area and look for a suitable berth there. The WSA Bingen and the river police (WSP) are contacting vessels directly there, and are organising the downstream passages from that point.
Contargo will now try to gradually bring all its barges back to the normal schedule by the end of the week. However, since all passages past the accident site are only permitted after individual requests from the river police, there may also be some delays over the next few days.