Sludge normal-temperature deeply dehydrating method

The invention discloses a sludge normal-temperature deeply dehydrating method which includes following steps: (1) adding a I-type sludge modification agent, a II-type sludge modification agent and a III-type sludge modification agent to the sludge being 90-98% in water content for conditioning and modification; (2) pumping the conditioned and modified sludge into a press-filtering machine and maintaining the pressure at 1.2-1.6 MPa for 40-50 min to dehydrate the sludge. In the invention, by means of the addition of the specially-use high-efficient composite sludge modification agents and an optimized press-filtering dehydrating process, the dehydration effect of sludge can be improved greatly. The sludge from a waste water treatment plant can be dehydrated to the water content of 40-50% by one step at the normal temperature, thereby satisfying national relative standard and specified requirement.