It is the sewage chamber, and the foul emulsion enters into the clean emulsion chamber after filtration through non-woven fabric paved on stainless steel mesh belt, and then flows into clean emulsion chamber through clean emulsion pipe. A circulating fan is installed on the top of filter, and the air exhausted by clean emulsion chamber is sent into foul emulsion chamber, and in the clean emulsion chamber forms slight negative pressure. Particles over 25um on the non-woven fabric is retained, and gradually forms into filter cake; as time goes on, the filter cake becomes more and more dense and the filtration speed becomes slower and slower; in addition, the vacuum degree of clean emulsion chamber will become higher and higher upon foul emulsion chamber’s liquid level rising, and when vacuum degree reaches set value or foul emulsion chamber reaches the high liquid level, the system will automatically issue signals, and switching on the reducer of stainless steel mesh belt, to move the non-woven fabric forward a certain length; on the other hand, the waste paper is sent to the collection boxes, and in the meantime, new non-woven fabric is paved on stainless steel mesh belt, so that a filtration circulation is completed. This process moves in cycles and continuous.