There are a lot of kinds of dehydrator for sludge arises from wastewater treatment plants. Among them, centrifugal dehydrator performs dehydration using centrifugal force. All dehydrators other than this is filtering type though, this dehydrator is only one which is centrifugal type. Also, there are two types in the centrifugal dehydrator which are decanter type and straight body type, and straight body type is used more often recently.
|■ Centrifugal dehydrator|
Sludge is fed into screw shaft of dehydrator from supply pipe settled inside of the screw shafts. Flocculants are also injected in the supply pipe at the same time, and sludge are made to be floc state by being mixed with the flocculants inside the supply pipe. When the screw shaft rotates with high speed, sludge in floc state is accumulated inside of cylinder surrounding the screw as it is being separated from water by centrifugal force. This cylinder outside the screw is rotating in the opposite direction from the screw rotation and dehydrated water is discharged from sludge supplying side. Sludge, on the other hand, is conveyed by screw as it is being dewatered, and discharged from sludge outlet in cake-like shape after dehydrated.
Difference between decanter type and straight body type is structure around sludge outlets. In straight body type, there is rapid change in cross-sectional area around the sludge outlet and strong squeezing force can be added on sludge because of this structure. Therefore, discharged dehydrated cakes has lower moisture content compared with decanter type.
As flocculants, there are two types which are two-packs type with inorganic plus polymer and one-pack type with polymer only, and the choice is made based on types and condition of sludge.
Water in the sludge thickened in the sludge thickener tank are removed at dehydration process to a certain degree.
However, moisture content is normally more than 80% and the sludge still has adhesiveness and stickiness. Also, latter processes are not easy because of influence of flocculants. Our drying apparatus of KENKI DRYER with international patented technology can surely dry any sticky, adhesive and viscus sludge, and also materials in liquid state like slurry, without clogging inside of the dryer. Also, because of its simple structure, its price is low and apparatus cost of the dryer can be retrieved by reducing industrial waste disposal cost within 3 years. Dried materials can be recycled as fuel, bacterial fertilizer, soil conditioner, etc. since component of the material is hardly changed because of its low-temperature drying method.
It can be applied to a system with pyrolysis apparatus as well.
Please refer to the following pages about effect of flocculants during drying process.
|Please consider KENKI DRYER for drying of sticky materials, adhesive materials and materials in liquid state that no other dryer can deal with.|
|Initial, running and maintenance costs are low because of its simple structure based on internationally patented technology.|
|For sludge drying, costs of our dryers are estimated to be retrieved within 2, 3 years by reducing industrial waste disposal cost.|
|For raw material slurry drying, laborious works of manual operation will be decreased significantly by replacing box shaped compartment tray dryer with our dryer|
|In case of organic wastes drying, the waste can be recycled as fuel, fertilizer, soil conditioner and feedstuff after being dried.|
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