JPS5951360B2 - Sludge treatment method for early stabilization of dewatering - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating sludge that accumulates in public water bodies and has an adverse effect on the living environment.

In order to prevent secondary pollution caused by pollution caused by construction work, dredging using a dedicated pump for sludge is often used.

However, pump dredging has a low gold mud rate and generates a large amount of surplus water.
The resulting effluent has various problems, including water treatment and early stabilization of high water content sludge.

In order to solve the problems of pump dredging as described above, this invention provides stable treatment of pump dredged sludge through early dewatering, and sludge treatment that makes it most economical and technically easy to treat the large amount of effluent water that is generated. It provides a construction method.

The details of this invention will be explained below based on the accompanying drawings.

In the figure, 1 is a reclaimed land, which is a desired public water area separated by an appropriate partition wall.

A large number of hollow pipes made of a water-permeable material such as porous concrete, that is, water-permeable pipes 2, are vertically erected and fixed at predetermined intervals in this reclaimed land 1.

A suction pipe 3 is inserted into each of the permeable pipes 2 and connected to a water collection pipe 4, and the water collection pipe 4 is connected to the suction port of a water collection pump 5, and a water discharge pipe is connected to the discharge port of the pump 5. Connect 6.

Reference numeral 7 denotes an introduction pipe for sludge sent from a dredging pump, and the sludge introduced into the landfill from this introduction pipe 7 is separated into concentrated sludge 8 and water 9 by coagulation and sedimentation using a flocculant or natural sedimentation.

The separated water passes through numerous pores in the water permeation pipe 2 and permeates into the water permeation pipe 2, and is collected by the water collection pump 5 via the suction pipe 3 and the water collection pipe 4, and is then discharged from the water discharge pipe 6 to the required parts. Water is sprayed on.

By the above method, SS in the separated water can be removed when it passes through the permeable pipe 2.

However, if the sludge contains water-soluble harmful substances, they cannot be removed, so the water permeable pipe 2 is filled with activated carbon or other granular adsorbent 8' as shown in FIG.

By filling the water permeation pipe 2 with the adsorbent 8' in this way, the T-N and O dissolved in the separated water that has permeated into the water permeation pipe 2 can be removed.
Harmful substances such as rg-P are adsorbed by the adsorbent 8', and the water from which the harmful substances have been removed passes through the suction pipe 3, the water collection pipe 4, the pump 5, and is discharged from the water discharge pipe 6.

In the conventional sludge treatment method, an attempt has been made to form a sand layer in the reclaimed land in order to quickly stabilize the dredged sludge, dredge the sludge on top of the sand layer, and after dredging, apply negative pressure to the sand layer to promote consolidation. However, it has been confirmed that negative pressure creates a well-consolidated impermeable layer above the sand layer, which inhibits consolidation.

In the construction method of this invention, since the water drains naturally, there is no need to worry about clogging of the permeable pipe, and even if it becomes clogged, it is easy to replace it with a new one.

Additionally, by changing the pitch of the permeable pipes, it is possible to control the rate of consolidation due to its own weight.

When purifying a public water body where sludge containing harmful substances has accumulated, a part of the public water body where the sludge has accumulated should be closed off with a dike to prevent the spread of harmful substances that cause secondary pollution. A construction method is being implemented in which the remaining sludge outside the closing embankment is dredged into the embankment and contained in situ.

This invention is a construction method that is particularly recognized for its excellence in the treatment of such areas that are closed off to public water bodies.

In other words, permeable pipes will be installed inside the closed landfill to remove seawater within the embankment.

At this time, if the filtered seawater does not contain harmful substances or eutrophic salts (generally, seawater does not contain them), it is released.

After discharge, the sludge to be dredged outside the embankment will be thrown in.

At this time, the separated water should be treated as water and harmful substances should be removed as described above.

In addition, it is also particularly effective to take measures against the elution of hazardous substances and implement solidification treatment from the early use of landfill sites.

The economic efficiency of solidification treatment work depends on the water content ratio of the sludge to be solidified.

In other words, the lower the water content ratio of sludge, the more economical it becomes.

In the above-described in-situ treatment, when water is drained using a water permeable pipe, the water content of the sludge remains at the in-situ level.

Although it can be solidified in this state, it is possible to further reduce the water content by drying in the sun or draining water using a permeable pipe.

After the solidification process, add the remaining sludge as described above,
After draining and lowering the water content ratio, assimilation treatment is performed.

Conventional methods for treating separated water in dredging and landfill construction involve leaving the separated water in the landfill until the SS and other contents in the separated water drop below the discharge regulation value, and then discharging it outside, or treating the generated separated water. Water removal treatment area is required.

For this purpose, either the sludge input to the landfill is reduced by the amount of separated water, or the planned volume of the landfill must be increased by the amount of separated water, which requires a vast water removal treatment area.

On the other hand, the method of the present invention allows water treatment to be carried out continuously, so the above-mentioned problem can be solved.

In addition, if the separated water contains harmful substances or other substances that may cause secondary pollution, a water treatment facility will be required, but in the method of this invention, an adsorbent is installed inside the permeable pipe. By filling, the permeable pipe itself becomes a water treatment facility.

Furthermore, since the water permeable pipe can be easily laid and the structure is simple, there is no malfunction and the self-weight consolidation after separation water removal can be promoted.

When stabilizing dredged sludge at an early stage using the consolidation method, the conventional method is to leave the dredged sludge alone for a long period of time, then pour a drain material such as sand drain, Hehart lane, or chemical drain into the sludge, and then preload the dredged sludge. However, in the method of this invention, as shown in Fig. 4, drain material 11 (sand, water slag, etc. )
It is also possible to promote compaction by filling the sand mat, laying a sand mat 12, and preloading.

As described above, the construction method of the present invention not only can be used as a vertical drain construction method, but also has the advantage that unlike conventional construction methods, there is no risk of sand cutting, and the construction period can be shortened.

[Brief Description of the Drawings] Figure 1 is a sectional view showing an embodiment of the construction method of this invention;
FIG. 3 is an enlarged vertical sectional view showing each side of the water permeable pipe, and FIG. 4 is a sectional view showing another embodiment. 1... Landfill, 2... Permeable pipe, 8'.
...adsorbent.

Claims (1)

[Claims] 1. A method for treating sludge deposited in public water bodies,
A public water area is closed off with an appropriate partition wall, multiple permeable pipes are installed to remove water from the water area inside the partition wall, and then the sludge to be dredged from the water area outside the partition wall is poured into the partition wall and settled. A sludge treatment method aimed at early stabilization of dehydration, which is characterized by separating water and concentrated sludge through treatment, and discharging the separated water that has permeated into a permeable pipe to a designated area. 2. In the treatment method for sludge deposited in public waters,
Either close off the public water area with an appropriate partition wall, install multiple permeable pipes and fill them with an appropriate adsorbent, or
Alternatively, install a plurality of water permeable pipes filled with an appropriate adsorbent inside the pipe to remove the water inside the partition wall.
After that, the sludge to be dredged carried on board outside the partition wall is charged into the inside of the partition wall and separated into water and concentrated sludge through sedimentation treatment, and the harmful substances in the separated water that have permeated into the permeable pipe are adsorbed by the adsorbent, and the separated water is a sludge treatment method aimed at early stabilization of dewatering, which is characterized by discharging it to a designated area.