JPH0734406A - Paving method - Google Patents

Abstract

PURPOSE:To reduce processing at purification plant. CONSTITUTION:Liquid or paste water supply sludge in sedimentation basin, concentrating tank, or sun dry furnace which is subject to a coagulating treatment with sulfuric acid aluminum, polyaluminum chloride, etc., or, after its treatment, subject to either of chemical filling treatment and non-chemical filling treatment is mixed with pavement soil material so that its volume ratio to the total becomes 30 to 80%. Then the mixture is arranged and stamped on paving base at a moisture content of 30 to 60% to form a paved surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paving method for forming paving surfaces for various sports facilities, schoolyards, promenades in parks, etc. by using tap water sludge collected from water purification plants.

[0002]

2. Description of the Related Art There is tap water sludge generated in the treatment process of water purification plants. In the process, sediment etc. are removed from the raw water taken from rivers etc. in the sand basin. Next, a flocculant such as aluminum sulfate (sulfuric acid band) or polyaluminum chloride (PAC) is added to settle the suspended matter in the settling tank. The coagulated and settled sludge is concentrated, dehydrated, dried and solidified by a chemical injection treatment method or a non-chemical injection treatment method.

A paving method in which the solidified sludge is crushed into particles and used for various sports facilities and other paving surfaces has already been considered and implemented.

[0004]

The water content of such sludge is about 95 to 98% in the sedimentation tank and about 90 to 95 in the concentration tank.
%, Both are liquid and fluid. When this is dehydrated and dried, it loses fluidity and becomes pasty, but in this case, the water content is about 70 to 85%.

However, in order to grind the sludge into particles,
It must be dried until the water content is around 60%.

Depending on the water purification plant, there is a place where the sludge is dehydrated and dried by sun drying, which requires a large treatment space and spends days for drying. Further, if mechanical dehydration is performed, the treatment can be performed in a short period of time, but there is a problem that high energy is required.

The present invention was devised in view of the above point, and provides a paving method using sludge from a sedimentation tank, a concentration tank or a sun drying bed before dehydration and drying, and simplifies the treatment. It is an object.

[0008]

According to the present invention, a coagulation treatment with aluminum sulfate, polyaluminum chloride or the like is performed, or after the treatment, either a chemical injection treatment method or a non-chemical injection treatment method is applied. Liquid or pasty sludge in a sedimentation tank, a thickener or a sun-dried bed is mixed with a paving earth material so that the total volume ratio is 30 to 80%, and the mixture is mixed with a water content of 30 to 60%. The pavement surface is formed by leveling and rolling on the pavement foundation at a rate.

In this case, tap water sludge may be mixed with the paving soil material on the paving foundation.

[0010]

[Function] Mixing tap water sludge with the soil material for pavement
When the soil is leveled and compacted at a water content of%, the sludge covered with the coagulant is broken into fine particles, and the sludge particles and the soil particles are adhesively bonded to each other. After this drying, it is cured to form a good paved surface.

The mixing ratio of tap water sludge and soil material for paving is
It is selected according to the amount of the coagulant contained in the tap water sludge and the physical properties required for the pavement surface, but a volume ratio of 30 to 80% is an appropriate range depending on the water content.

Mixing the tap water on the paving foundation while mixing the groundwater sludge with the paving material eliminates the need for a mixer or the like.

[0013]

[Example] Liquid tap water sludge in a sedimentation basin to which a flocculant such as aluminum sulfate or polyaluminum chloride was added, or after the treatment, either a chemical injection treatment method or a non-chemical injection treatment method was applied. Use liquid or pasty sludge from the concentration tank or sun dried bed.

The water content of this sludge is 70 to 98%,
This sludge is mixed with the soil material for paving (loam, silty clay, fine sand and Arakida soil which is a mixture of these) so that the volume ratio of the entire sludge is 30-80%, and the mixture is thoroughly mixed with a kneader or the like. .

Next, the water content of this mixture is 30 to 60%.
If necessary, adjustment such as drying is performed so as to keep the temperature at 1, and the mixing is repeated again.

Then, this mixture is laid on a paving foundation and, while maintaining the water content, it is leveled and compacted by using a tire roller or the like.

When the water content exceeds 60%, it may be dried while being laid on the paving foundation.

When sludge that has been dried in advance and pulverized into particles is used, it may be necessary to sprinkle water in the summer, but if the water content is high like this sludge, water sprinkling is unnecessary.

Further, the sludge and the paving soil material may be mixed after being laid on the paving foundation. In this case, while digging up with a tractor etc., mixing,
Stir.

Mix the sludge with the paving earth material,
When the soil is leveled and compacted at a water content of 100%, the sludge covered with the flocculant easily breaks into fine particles, and quickly enters the gaps between the soil particles, causing the sludge and soil particles to stick to each other. Join.

After the drying and curing, a paved surface is formed. The mixing ratio of the sludge and the soil material for paving is determined according to the amount of the coagulant contained in the sludge and the physical properties required for the paving surface, so as to maintain the above-mentioned water content (30 to 60%), The volume ratio is appropriately selected within the range of 30 to 80%.

As described above, since the sludge from the sedimentation tank, the concentration tank or the sun drying bed before the dehydration / drying treatment is used, the treatment at the water purification plant can be greatly reduced, and high effective utilization can be achieved.
Get excellent practicality.

On the paved surface using such sludge, the particles of the sludge and the soil of the soil material are coated with a coagulant, and further the particles of the sludge and the soil are ground by the compaction, and the silt of the soil, Since the sludge and soil particles adhere to each other adhesively due to the clay quality, it becomes difficult to dissolve in water after drying and curing, and it hardly breaks or becomes dust even when shock is applied, and extremely high durability Show.

Further, since the fine particles contained in the soil material are aggregated by the effect of the added coagulant, gaps remain between the particles, the water permeability is improved, and rainwater is quickly absorbed into the underground layer. Therefore, in addition to having high water resistance, it can be used immediately, and since it does not retain water, it is less likely to cause frost damage in winter.

Further, the finished product retains an appropriate elasticity as in the conventional soil pavement, so that the feeling of use is good.

[0026]

Industrial Applicability As described above, according to the present invention, it is possible to easily obtain a pavement surface which has good properties peculiar to soil pavement, has excellent durability and water resistance, and does not require maintenance. This has the effect of significantly reducing the amount of wastewater treatment and making effective use of tap water sludge while conserving resources.

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Claims (2)

[Claims] 1. A settling tank, concentrating tank, or sun which has been subjected to a coagulation treatment with aluminum sulfate, polyaluminum chloride, or the like, or which has been subjected to either a chemical injection treatment method or a non-chemical injection treatment method. The liquid or pasty sludge in the dry bed is mixed with the paving soil material so that the volume ratio of the whole is 30 to 80%, and the mixture is mixed with 30 to 30%.
A paving method characterized by forming a paved surface by leveling and rolling on a paving foundation with a water content of 60%. 2. The paving method according to claim 1, wherein the tap water sludge is mixed with paving soil material on a paving foundation.