Domestic decanter centrifuge use AB technology, design a kind of sewage treatment capacity 140,000 m3/d of wastewater treatment systems. The treatment process produced excess sludge, and the excess sludge through enrichment and digestion processing, can produce nearly 700m3 moisture content of about 94% sludge everyday. The decanter centrifuge put into operation Since November 1992, there had the use of imported and domestic belt filter press to dewater sludge. But with the increase of influent suspended solids, sludge production is increasing. This leads to excess sludge generated by the water treatment process can not be treated in time, this seriously affect the normal operation of the water treatment process. Through research, investigation and evaluation, and on the basis of on-site sludge dewatering tests, the experts decided to adopt domestically decanter centrifuge sludge dewatering units. They chose DE-1000 Decanter centrifuges. DE-1000-type decanter centrifuge sludge dewatering unit mainly contains DE-1000 type Decanters, automatic flocculant dosing device, sludge crush cutter, into the mud pumps, dosing pumps, single screw conveyor sludge pumps, flow meters and automatic control systems and some other structures.
Decanter centrifuge are the abbreviation of horizontal spiral centrifuge discharge. It mainly consists of high-speed rotation drum, differential, the helical that its turning are at the same speed and slightly lower as rotation drum, and other components. When the sludge into the centrifuge drum cavity, the high-speed rotation drum produces a powerful centrifugal force. Because the sludge particles’ density is large, so the centrifugal force is also large, and therefore the sludge left behind attached to the drum wall, forming a solid ring layer. The density of water is small, the centrifugal force is small, so it only form a liquid ring in the inner of the solid ring layer. Due to the different speed of spiral and drum, so there is a relative motion( differential speed)between them. This discharges the sludge what is deposited on the drum inner wall to the small end of the drum, the separated water is discharged from the other end of the drum. The differential mechanism’s effect is to form a certain speed difference between the drum and the screw. Add some flocculant into the sludge to produce flocculation, gather the dispersed particles and produce a greater floc, then accelerate the mud separation.
The units’ processing capacities are the followings. Under the conditions of Into the mud moisture content of about 94%, each unit’s capacity is about 20 ~ 30m3/h. Hourly production of dried mud (water content was zero sludge) 1.2 ~ 1.8t, the maximum capacity of each unit is 720m3/d. DE-1000-type decanter centrifuge machine adopts dual-frequency dual-motor drive mode. Drum and spiral driven by the main motor, the speed difference between the drum and spiral auxiliary motor driven by differential braking force to achieve power generation. Auxiliary motor works are in the power state, do not consume energy. Decanter centrifuge hosts’ current consumption is less than the main motor of the auxiliary motor current minus current generation. Main motor’s power is 30kW, mainly taking into account the centrifuge drum and spiral moment of inertia, configure high starting currents.