Abstract: A method for treating polluted material such as industrial waste water or polluted water from other sources, sewage or sewage sludge or other forms of sludge, or polluted soil, to degrade oxidizable substances therein, comprising subjecting the polluted material to a wet oxidation process in a reactor so as to decompose and/or modify oxidizable substances therein and optionally improve the filterability of solids when present in the material; the material may optionally be pretreated so as to facilitate the wet oxidation process. Solid polluted material is preferably in the form of a liquid suspension, such as an aqueous suspension, when subjected to wet oxidation. The wet oxidation process is performed to such an extent, optionally with subsequent substantial removal of heavy metals, that the decomposed and/or modified substances remaining after the wet oxidation and the optional removal of heavy metals are substantially biodegradable.

Abstract: An overfill protecting arrangement for a liquid storage tank comprises in combination a venting valve and a spill valve. The arrangement is designed for a maximum permissible loading rate, and the venting valve is so dimensioned that at this loading rate the tank pressure will assume an equivalent value substantially lower than a safety limit value prescribed by the authorities. The spill valve is a quick-opening valve, preferably a magnetic value, which has an opening pressure distinctly higher than said equivalent value of the tank pressure and lower than said safety limit value. The drops of pressure caused by a flow of liquid at the loading rate into the venting valve system and out of the fully open spill valve are so co-ordinated that flow of gas out of the spill valve and flow of liquid out of the venting valve cannot occur at any circumstances.