JPS6157080B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a freeze-thaw sludge treatment apparatus, and particularly to a chemical-free sludge treatment apparatus.

FIG. 1 shows a conventional sludge treatment device of this type, in which organic sludge 1 is discharged from a water treatment device (not shown) and organic sludge, such as ferric chloride, is injected from a chemical injection device 5. Mixer 2 mixes the flocculant with the supernatant liquid by injecting the flocculant.
A pre-concentration device 3 separates the sludge from the sludge having a moisture content of 2.0% or more, and 3 freezes the sludge supplied from the pre-concentration device 2, then thaws it to separate it into solids and water with good dewaterability. freeze-thaw equipment,
4 is a centrifugal separation-type or vacuum-type dehydration device that dehydrates the sludge modified by the freeze-thaw device 3 and separates it into a dehydrated cake and a filtrate;
It goes without saying that the dehydrated cake produced in this dehydrator 4 is incinerated, landfilled, or used for composting or the like.

As mentioned above, conventional freeze-thaw sludge treatment equipment inevitably uses agglomeration of ferric chloride, etc. to make it easier to separate the organic sludge discharged from the water treatment equipment into solids and water. A satisfactory dewatering operation cannot be achieved without injecting a chemical agent, and therefore, the dehydrated cake produced during the sludge treatment process and the effluent inevitably contain heavy metals due to impurities in the flocculant. Pollution is a problem.

Therefore, in order to solve the above problems, we focused on the fact that the dewatering performance of freeze-re-thawed sludge is significantly improved when the pH of the sludge to be treated decreases, and by directly deionizing the sludge, the PH of the sludge is A device that directly lowers the temperature and then freezes and re-thaws it is considered. However, in this device, the deionization device is frequently clogged with sludge. Although these contaminations and clogging can be avoided by using a suitable cleaning method for the deionization equipment, there is still a problem that cleaning operations are necessary and the equipment operation becomes complicated.

This invention was made by focusing on this point, and uses acidic water made by converting only the cations into "H ⁺ " ions from a portion of the water discharged outside from the same water treatment facility to sludge. By adding a drug-free product, it is possible to achieve the same level of sludge dehydration effect as when using a flocculant, without using conventional flocculants, i.e., chemicals such as ferric chloride. The present invention aims to provide a sludge processing device.

That is, FIG. 2 shows an embodiment of the present invention, in which 21 is a water treatment device into which wastewater to be treated such as sewage flows, and 22 is a part of the water discharged from this water treatment device 21. 23 is a cation-exchange resin packed tower that exchanges only cations from the divided discharged water and converts it into acidic water with increased hydrogen ions; 24 is the water treatment device 21;
A mixer 3 mixes the sludge discharged from the cation exchange resin packed tower 23 with the acidic water supplied from the cation exchange resin packed tower 23, and a mixer 3 freezes the sludge supplied from the mixer 24, then thaws it to dewater it. freeze-thaw equipment for good separation of solids and moisture;
Reference numeral 4 denotes a centrifugal or vacuum type dewatering device that dehydrates the sludge modified by the freeze-thaw device 3 and separates it into a dehydrated cake and a filtrate. In Figure 2, A is the water treatment system,
B shows a sludge treatment system.

Since the freeze-thaw sludge treatment apparatus of the present invention is constructed as described above, a part of the discharged water separated from the sludge by the water treatment apparatus 21 is passed through the divider 22 to the cation exchange resin packed column. Sent to 23. The discharged water sent into this cation exchange resin packed tower 23 has a specific electrical conductivity K (μ
/cm) is around 5,000, so by passing it through this cation exchange resin packed tower 23, the absolute amount of hydrogen ion concentration can be increased, making it possible to make acidic water with a lower PH value. It is.
Then, when the acidic water discharged from the cation exchange resin packed tower 23 and the sludge discharged from the water treatment device 21 are mixed in the mixer 24,
The pH value on the sludge side decreases and proteins in the sludge aggregate. This is indirectly observed as a browning reaction, and the pH value of the sludge at this time is around PH4, which is the point where a small amount of acid has the greatest effect, as shown in Figure 3. Recognize. In this way, the mixed sludge is reformed in the next freeze-thaw device 3, and then turned into a dehydrated cake in the dewatering device 4.

In the above embodiment (Fig. 2), the sludge to be treated is sewage, but in addition to this sewage, human waste treated sludge,
The above mixer 2 can also be applied to the treatment of organic sludge such as septic tank sludge.
A concentrator may be inserted before or after step 4.

As described above, according to the present invention, the water treatment device and the sludge treatment device are organically combined,
The sludge dehydration effect can be fully demonstrated without using dangerous chemicals that are coagulants for sludge as in the past, and a dehydrated cake that does not contain chemicals and has a low moisture content can be obtained. It is effective.

In addition, the acidic water added to the sludge uses discharged water from a water treatment equipment with very little SS (suspended) components as a raw material, so there is less clogging caused by SS components in the cation exchange resin packed column, making it practical for practical use. The above has the advantage that cleaning operations are unnecessary.

[Brief explanation of the drawing]

FIG. 1 is a piping diagram showing a conventional freeze-thaw sludge processing apparatus, FIG. 2 is a piping diagram showing an embodiment of the present invention, and FIG. 3 is a characteristic diagram of sludge treatment effects. In the drawing, 3 is a freeze-thaw device, 4 is a dehydration device, 2
1 is a water treatment device, 22 is a divider, and 23 is a cation exchange resin packed column. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. Hydrogen ions obtained by ion-exchanging only the cations of a portion of the effluent water separated from the sludge by the water treatment equipment in a cation-exchange resin packed column are placed in the front stage of the freeze-thaw treatment equipment that has a dehydration equipment in the latter stage. A mixer is provided that lowers the pH of the sludge to a predetermined value or less by mixing the increased acidic water with the sludge discharged from the water treatment equipment, and then supplies the sludge to the freeze-thaw treatment equipment. Freeze-thaw sludge processing equipment characterized by: