The present invention provides a drying apparatus. The apparatus includes a first, upper chamber comprising a freezing section; and a second, lower chamber comprising a thawing section and a drying section. The first, upper chamber further includes an inlet and first conveying means arranged to convey material through and within the freezing section. The second lower chamber includes second conveying means arranged to convey material through and within the thawing section, and third conveying means arranged to convey material through and within the drying section. A first outlet is provided in the drying section through which dried material exits the apparatus. Generally, the material provided to be dried by the drying apparatus is alum sludge.

The present invention provides a drying apparatus. The apparatus includes a first, upper chamber comprising a freezing section; and a second, lower chamber comprising a thawing section and a drying section. The first, upper chamber further includes an inlet and first conveying means arranged to convey material through and within the freezing section. The second lower chamber includes second conveying means arranged to convey material through and within the thawing section, and third conveying means arranged to convey material through and within the drying section. A first outlet is provided in the drying section through which dried material exits the apparatus. Generally, the material provided to be dried by the drying apparatus is alum sludge.