a water bath separator 52 where heavy substances such as glass and stones but also fine substances like sludge and organic waste are separated from it by means of clarification from the water bath separator 52 the waste is passed to a second wind sieve 53 of the process where by means of an air flow wood is separated from other waste which at this point comprises mainly plastics plastics waste can be recovered as such or it can be passed to the separation phases 48 of aluminium and pvc together with the indecomposable reject from pulping 45 contaminated wood containing wood preservatives or other contaminants can further be separated from the wood fraction recovered from the wind sieve 53 by means of an x ray device 54 or another known separation method after this the contaminated wood can be incinerated for example in a fluidised bed boiler having flue gas purification equipment required by the eu waste incineration directive pure wood can be used as a raw material for chipboard or as fuel from the process shown in fig1 a pure fibre fraction and different wood plastics and metal fractions are recovered which may be reused either as a raw material or as fuel a further alternative is to provide between the wind sieve 44 and the pulping station 45 equipment for separating different paper fractions from each other on the basis of color.