JPH0199700A - Sludge dewatering treatment method - Google Patents

Abstract

PURPOSE:To deodorize sludge without degrading the flocculating function of a cationic high-polymer flocculating agent to the sludge and to efficiently carry out a dehydration operation without degrading environment by adding slaked lime to the gravity-dehydrated sludge to deodorize the sludge prior to force dehydration. CONSTITUTION:The sludge generated by various water treatments of night soil, city sewage and industrial waste water is flocculated to large flocs by addition of the cationic high-polymer flocculating agent thereto. The water liberated among the flocs by gravity dehydration is efficiently removed in a large volume. The slaked lime is added to such gravity-dehydrated sludge prior to the force dehydration, by which the sludge is efficiently deodorized in the state of decreasing the amt. of the slaked lime to be dissolved in filtrate.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a sludge dewatering treatment in which sludge is flocculated by adding a cationic polymer flocculant and then subjected to gravity dewatering, and the gravity dehydrated sludge is further forcibly dehydrated. Regarding the method.

[Conventional technology]

In the conventional sludge dewatering treatment method, sludge and dehydrated sludge tend to emit odors, and the environment is degraded when storing, transporting, and incinerating the sludge, so slaked lime to deodorize the sludge is not used.
It has been considered to add it to the sludge simultaneously with the addition of the polymer flocculant.

[Problem that the invention seeks to solve]

However, while cationic polymer flocculants work effectively on sludge at a pH of 5 to 9, when the minimum amount of slaked lime is added to deodorize sludge, the sludge has a pH of 5 to 9.
In the end, only small flocs are formed, which not only reduces the dewatering efficiency, but also makes it difficult for the sludge deodorizing effect to increase ( In order to maintain this condition, the amount of slaked lime added must be increased.

An object of the present invention is to deodorize sludge without reducing the flocculating function of a cationic polymer flocculant.

[Means for Solving the Problems] The characteristic means of the sludge dewatering method of the present invention is that slaked lime is added to deodorize the sludge after gravity dewatering before forced dewatering. The effects are as follows.

[For production]

In other words, the sludge is flocculated by adding a cationic polymer flocculant to form large flocs, and then the water released between the flocs is efficiently dehydrated in large quantities by gravity dewatering.
By adding slaked lime to sludge with reduced water content,
Slaked lime rarely dissolves into the filtrate and has an efficient deodorizing effect.

〔Effect of the invention〕

Therefore, sludge can be deodorized without reducing the sludge flocculating function of the cationic polymer flocculant, and dewatering work can now be carried out efficiently without deteriorating the environment.

Moreover, since the amount of slaked lime eluted into the filtrate is small, the amount of slaked lime used for sludge deodorization can be reduced, improving economic efficiency. The added slaked lime has a larger particle size than the sludge, so
As a dehydration aid, dehydration efficiency can be further increased.

,〔Example〕 Next, embodiments of the present invention will be described based on the drawings.

As shown in FIG. 2, a mixer ( 3), an endless strip-shaped first rotating filter cloth (4), and a case side wall (5).
) and the partition wall (6), a gravity dehydration section (7) is formed between which the agglomerated product from the mixer (3) is supplied and water is filtered by gravity, and the gravity dehydration section (7) A thickness adjustment roll (8) for adjusting the thickness of the sludge cake carried on the first rotary filter cloth (4) is provided on the lower side in the rotating direction of the filter cloth (4), and the lower side thereof. A second rotary filter cloth (9) is provided between the first concave filter cloth (4) to pinch the cake whose thickness has been adjusted, and a width pressure dewatering zone (^) of a linear path is provided. , compression dewatering zone (B
), and a forced dehydration section (10
), thereby forming a gravity dewatering section (7) of the first filter cloth (4).
) to the forced dewatering section (10), the belt press continuously dewaters materials to be treated such as sludge generated in various water treatments such as human waste, urban sewage, and industrial wastewater. In order to deodorize the sludge from the belt press type dehydrator, an addition device (12) for adding slaked lime to the gravity-dehydrated sludge is installed before the thickness adjusting roll (8). It is arranged.

In other words, when deprocessing sludge, the deodorizing method for sludge is explained step by step using the block diagram in Figure 1. After sludge is flocculated by adding a cationic polymer flocculant, it is dehydrated by gravity. Slaked lime is added to the dehydrated sludge to deodorize the sludge, and then the sludge is forcibly dehydrated.

In addition, the polymer flocculant is 0.5 to 1.5 wt%, and 1
A floc of m to 5 ml is formed, and at least 3 to 5% of slaked lime is added to deodorize the sludge, and odor components are deodorized by the adsorption action of the slaked lime.

[Another example]

The slaked lime added to the sludge may be in the form of a powder or a solution.
) may be immediately after.

In order to perform the forced dehydration, a method such as a centrifugal dehydrator may be used instead of using a belt press type dehydrator.

A stirring device may be provided at the slaked lime addition point before the thickness adjusting roll (8) in order to improve the mixing of the sludge and slaked lime.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an example of the sludge dewatering treatment method according to the present invention,
FIG. 1 is a block diagram showing the overall processing method, and FIG. 2 is a schematic side view of the belt press type dehydrator.

Claims (1)

[Claims] This is a sludge dewatering treatment method in which sludge is flocculated by adding a cationic polymer flocculant and then subjected to gravity dewatering, and the gravity dehydrated sludge is further forcibly dehydrated.
A sludge dewatering method that deodorizes sludge by adding slaked lime before forced dewatering.