Water Purification And Sewage Disposal

breweries, injures the complete action of yeast, etc. Certain micro-organisms absorb it to a still greater degree than iron. Manganese almost always accompanies iron, but the amount is generally so small that its presence in the majority of cases does not approach practical importance at all. Proska-uer was the first to point out the occurrence of manganese salts in water. Manganese is removed by aeration, like iron, but it separates out with greater difficulty, since, during aeration, mangani- manganous compounds result, which are soluble to a considerable extent in water. The calamity in Breslau originated in consequence of the existing geological conditions. Iron and manganese sulphides, in the humous layers situated over the ground-water, were converted to sulphates by oxidation and then passed into the ground-water owing to a flood which inundated the whole tract of country. For the removal of manganese, and also of iron, Permutit has recently been recommended. Permutit is an artificially prepared product (aluminium silicates), principally employed in the softening of water (see page 60). Permutits have the property of withdrawing from water, lime, magnesia, iron, and manganese, in exchange for sodium, if the water be allowed to flow over them. Luhrig and Becker, Gaus and Noll, have carried out experiments on the removal of manganese by means of calcium permutit. The manganese is thereby exchanged for calcium. Whilst Luhrig and Becker obtained goo... --This text refers to the Paperback edition.