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Dewatering treatment of farm manure

Bluslot® Solid Liquid Separator

The breeding manure need to be dewatering: cow manure, pig manure, chicken manure, duck manure, etc.

There are two kinds of aquaculture manure treatment: dry and wet manure separation and biogas slurry separation. 
At present, the most mainstream dry and wet manure separator in the market is the screw extruder, which can separate the coarse fiber of manure and reduce the slag content when manure water enters the next process, which is more conducive to the subsequent sewage treatment. 
When the manure water enters the anaerobic fermentation tank, it needs to undergo fermentation for about 40 days. The fermented wastewater is called biogas slurry, and the biogas slurry needs to be deslagging. The deslagging biogas slurry wastewater enters the sewage treatment system again for further treatment, and finally meets the discharge standard. 
At present, the mainstream equipment in the market for the separation of biogas slurry and biogas residue is centrifuge and screw stacker. Screw stacker is suitable for farms with small processing capacity, while centrifuge is suitable for farms with large processing capacity. Of course, centrifuge is applicable regardless of large and small volume, while screw stacker is not suitable for large farms unless you use many. 

Comparison between stacked screw dewatering machine and centrifugal dewatering machine. Working principle of screw stack dewatering machine: when the screw driving shaft rotates, the multiple fixed and movable laminations arranged on the periphery of the driving shaft move relatively. Under the action of gravity, water is filtered out from the relatively moving lamination gap to realize rapid concentration. Dewatering: the concentrated sludge moves forward with the rotation of the screw shaft; Along the outlet direction of the mud cake, the pitch of the spiral shaft decreases gradually, the gap between the rings also decreases gradually, and the volume of the spiral cavity shrinks continuously; Under the action of the back pressure plate at the outlet, the internal pressure increases gradually. Driven by the continuous operation of the spiral drive shaft in turn, the water in the sludge is extruded and discharged, and the solid content of the filter cake increases continuously, so as to finally realize the continuous dehydration of the sludge. Self cleaning: the rotation of the screw shaft promotes the continuous rotation of the traveling ring. The equipment realizes the continuous self-cleaning process by relying on the movement between the fixed ring and the traveling ring, so as to skillfully avoid the common blockage problem of the traditional dewatering machine.

Working principle of centrifugal dewatering machine: the centrifugal sludge dewatering machine uses the density difference between solid and liquid phases to accelerate the settling speed of solid particles under the action of centrifugal force to realize solid-liquid separation. The specific separation process is that the sludge and flocculant solution are sent to the mixing chamber in the drum through the inlet pipeline for mixed flocculation (if the sludge is added in front of the pump or in the pipeline behind the pump, the flocculation reaction has been carried out in advance). Due to the high-speed rotation and friction resistance of the rotor (screw and drum), the sludge is accelerated inside the rotor and forms a cylindrical liquid ring layer (liquid ring area), Under the action of centrifugal force, the solid particles with large specific gravity settle to the inner wall of the drum to form a mud layer (solid ring layer), and then use the relative speed difference between the screw and the drum to push the solid phase to the cone end of the drum. After pushing out the liquid level (shore area or drying area), the sludge can be dehydrated and dried, and finally discharged to the discharge outlet.

From the moisture content of the treatment results, both are about the same, both about 80%. In terms of processing capacity, the centrifuge will be relatively larger. In terms of power consumption and energy consumption, the screw stacker consumes the least power due to the low-speed operation of the motor. The centrifuge consumes a lot of power due to the high-speed operation of the motor. In terms of automation, the screw stacker can realize 24-hour unmanned automatic operation without personnel on duty. Centrifuges can also be achieved. In terms of investment, the early stage of screw stacker may be relatively high. As a whole, the initial investment is similar to that of screw stacker. In addition, it is not necessary to return to the factory for the maintenance of the laminated screw. If there is a problem with the machine to the extent that the traveling ring needs to be replaced. Of course, there are many domestic screw stacking machine manufacturers. It is inevitable that some manufacturers produce machines with poor quality, insufficient accuracy, low hardness, easy damage and frequent maintenance. The general service life of centrifuge is 10-15 years. It is used for biogas slurry dehydration. Generally, it can be used for 3-5 years before bearing replacement. It can be said that the maintenance cost is very low. The main difference between the two is the processing capacity.

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