KR810000814B1 - Method for dehydration of sludge - Google Patents

Abstract

Waste sludge contg. cellulose of paper manufacturing plant is dehydrated efficiently by mixing 1-10 wt. % (on the basis of 80 wt.% water contg. sludge) dehydration accelerator such as rice hull, sawdust and the bark-milled finely. When the sludge is mixed with 1-10 wt. % rice hull and 40-50 wt. % bark, the content of water is decreased to 56.0 wt. %. (If the sludge is dehydrated independently, the content of water is to be 74.0 wt. %.)

Description

Dewatering method of sludge

The present invention relates to a method of dehydrating moisture by mixing fiber such as chaff and sawdust in a sludge.

Until now, the biggest problem in the treatment of wastewater by using sedimentation basin as one of the pollution prevention measures in the pulp and paper industry is the disposal of sludge caused by wastewater treatment. After sedimentation by using sedimentation basin etc., it is dehydrated by vacuum dehydrator and so on after being dehydrated around 80% of moisture content, but this method contains about 80% of water in the sludge. In addition, in case of incineration, a large amount of fuel is consumed due to excess moisture, which is an uneconomical defect.

As a method to solve this problem, there is a method of pressurizing and dehydrating the water content around 60% by using a screw press or hydraulic press, but this method also includes fine fibers, treatments, etc. Because of the large amount of water, poor water availability has been a major obstacle in reducing the water content of the sludge.

The present inventors have studied and researched to solve these drawbacks, but using the same press as the conventional but the sludge (80% moisture content basis) by weight ratio of 1-10% by mixing the fiber, such as chaff, sawdust, dehydration, Not only was the water content reduced by about 10% compared with no addition, but this could also be enormous in terms of fuel savings if it was seen or incinerated in an incinerator.

In the present invention, in order to further improve the dehydration efficiency, after mixing chaff sawdust and the like at a ratio of 1-10% by weight of the sludge, it is mixed with finely broken bark (Bark) again, and the effect is remarkably improved. Able to know.

Examples of the treatment process of the present invention are as follows.

TABLE 1

In order to analyze the combustion value, the analysis cases of the calorific value of the sludge and the bark are as follows.

TABLE 2

TABLE 3

Compression and dehydration of the sludge in the hydraulic press by the conventional method is as follows.

TABLE 4

As shown in the table above, the sludge dehydrated poorly and the crimped state was not good. When the sludge was dehydrated alone, the water content was high and not combusted, and a large amount of fuel was needed to incinerate it. .

As such, when the sludge is dehydrated alone, the dehydration state is very poor. In the present invention, the bark is mixed with a dehydration aid and dehydrated to obtain a result as shown in Table 5 below.

TABLE 5

(Note) The bark used in this test was used before and after 75% of finely ground moisture content.

As shown in the test results of Table 5, the dehydration test resulted from the dehydration test by mixing the bark and the sludge was significantly improved. Reduced and burned without fuel in the boiler, producing a large amount of steam,

In addition, as the blending ratio of the sludge increased more than 35%, the dehydration state worsened, and when blending more than 50%, the moisture after dehydration was found to be remarkably poor, more than 60%.

Generally, if a large amount of bark is available, it is a slot dehydration accelerator as above 30% as above.However, when formulated, the dehydration is good to maintain enough fuel value, but most of the bark is easily obtained. The reality is that the bark mix is often only a small amount.

In this study, considering the reality, the test shown in Table 6 was conducted.

TABLE 6

As shown in Table 6, when the sludge ratio is increased to more than 50%, it can be seen that using chaff also sawdust as a dehydration accelerator significantly improves the effect.

Note: The bark is advantageously ground as finely as possible, and the higher the bark ratio, the better the dehydration effect.

In addition, when the water content is reduced, the sludge is valuable as a fuel when the fiber content is large, but the handling cost such as transportation costs due to the landfill can be significantly reduced since the volume is reduced by the decrease of the water content.

TABLE 7

Claims (1)

As described in the text, as the dehydration accelerator of the sludge, fiber, such as chaff and sawdust, is mixed at a ratio of 1 to 10% by weight of the sludge (based on 80% moisture content), and then dehydrated or finely shredded bark. The method is to dehydrate the sludge using a pressurized dehydrator such as a screw press or a hydraulic press, which is mixed again by using a conventional method.