JPS5817897A - Dehydrating method for sludge - Google Patents

Abstract

PURPOSE:To obtain dehydrated cake which is self-burnable quickly in the stage of dehydrating the sludge drawn from a treating tank under pressure by mixing dried solidifiable powder with the primarily dehydrated cake. CONSTITUTION:The sludge 1 drawn from a treating tank is dehydrated to about 90% water content with a meshed drum to primarily dehydrated cake 2. Said cake is decomposed to sludge 3 of around 10mm. grain sizes with a decomposing device, and dried incineration ashes are added to said cake at about 150- 200% the weight expressed in terms of the weight of the dry cake. The cake and ashes are quickly and roughly mixed to stick the incineration ashes on the surfaces of the sludges 3, whereby solidified shells 4 of the incineration ashes contg. voids among the grains of the sludge 3 are formed. Since the shells 4 softens by absorbing the water of the sludge upon elapsing of time, the mixture of both is quickly placed between filter cloths and is crushed 5 with a pressurizing press. The water oozed from the sludge by pressure is accelerated of discharging by the voids of the shells 4, whereby the cake is easily dehydrated to secondary dehydrated cake of about 35-45% water contents.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for dewatering activated sludge extracted from a treatment tank.

Conventionally, activated sludge that has been coagulated and precipitated by a flocculant in a treatment tank is extracted from the treatment tank and processed by using a rotary mesh drum to reduce the moisture content. The inside and outside of the row was dehydrated, and then this sludge with a water content of 90% was put into a direct combustion furnace and incinerated.

However, this method has a limit to the dewatering of sludge, and the drying and incineration of the sludge after dewatering requires t"
The disadvantage is that it consumes a large amount of heavy oil, amounting to 1,740 kg.

An object of the present invention is to provide a method for dewatering sludge that can overcome the drawbacks mentioned above and save fuel required for drying and combustion.

The purpose of this invention is to handle the water-containing sludge with ease! Using the moisture in the decomposed sludge, a dry powder is attached to the surface of the sludge to form a solidified shell (this solidified shell increases in water content over time and becomes softer). The turtle attempts to dehydrate the sludge by crushing the sludge that has formed a solidified shell and draining the water from between the crushed and solidified shells.

An embodiment of this invention will be briefly explained with reference to FIG.

The extracted sludge from the treatment tank is dehydrated to a water content of about 9096 in a gourd drum to form a primary dehydrated cake-2. This dehydrated cake is then passed through a decomposition device into decomposed sludge with a particle size of about 10%. This decomposed sludge ink contains 1 io-to of the weight of this decomposed sludge converted into dry cake.
ol! 0 dried and incinerated ash is added and roughly and quickly mixed to cause the incinerated ash to adhere to the surface of the decomposed sludge S, forming a solidified shell 4 of incinerated ash containing voids between each decomposed sludge ink. As time passes, this solidified shell 4 absorbs moisture from the sludge and becomes soft, so when the mixture of decomposed sludge S and solidified shell 4 is quickly sandwiched between filter cloths and crushed by a pressure press 5, the pressure from the sludge is removed. The water is easily dehydrated by promoting drainage through the voids of the solidified shell 4, and the crushed sludge becomes a secondary dehydrated cake containing water.

When this secondary dehydrated cake is put into the incinerator and ignited 6,
It self-combustes.

As explained above, this invention can extract almost all sludge! After dehydrating the hydrated coal, coagulable powder is added to the sludge to create voids of solidified shells in the sludge.In addition, the voids of the solidified shells promote drainage of pressurized water and facilitate dewatering. Since it is easy to produce, a self-combustible dehydrated cake can be obtained quickly even if heavy oil heating, sun drying, etc. are omitted, and it has the effect of saving fuel.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a sludge dewatering process according to an embodiment of the present invention. 1: Extracted sludge, 2! - Next dehydrated cake, 68 decomposed sludge, 4
! Solidified Shell Representative Patent Attorney Takashi Honma Momo

Claims (1)

[Claims] In a method for dewatering sludge extracted from a treatment tank so that it can be incinerated, the extracted sludge has a high water content. A method for dewatering sludge, characterized by forming a raw dewatered cake, mixing this dehydrated cake with a dried coagulable powder to form a solidified shell having voids, and further crushing the formed dewatered cake tube.