JPS59122813A - Method for drying and incinerating sludge of waste water treatment - Google Patents

Abstract

PURPOSE:To enable drying and incinerating of sludge without using heavy oil, by a method wherein, through employment of a rotary kiln type incinerator having a drying and an incinerating part, a combustible industrial waste material, substituted for heavy oil, is used as fuel for assist combustion. CONSTITUTION:The dehydrated sludge A1 of waste water treatment, dehydrated by a dehydrator 8, is conveyed to a mixer 4 to mix it with a combustible waste material. The mixed sludge is supplied to a drying part 2 through a feed port 5, and is dried by means of combustion gas from an incinerating part 3. A dried sludge B, dried by the drying part 2, is conveyed to a mixer 6 to mix it with the dehydrated sludge A2 and the combustible waste material C. The mixture, fed to the incinerating part 3 through a feed port 7, is incinerated through assist combustion of the combustible waste material. Exhaust gas is utilized as a heat source for drying of sludge in the drying part. This permits drying and incinerating of sludge without using heavy oil.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for drying and incinerating activated and coagulated sludge generated from pulp manufacturing processes and various wastewater treatment facilities.

Conventionally, for example, sludge generated from activated sludge equipment and coagulation sedimentation equipment, which are pulp wastewater treatment equipment, has poor dewatering properties and has a high water content, making it impossible to self-combust. When disposing of waste after incineration, the cost of incineration was high.

The purpose of the present invention is to eliminate these drawbacks by using a rotary kiln type incinerator equipped with a drying and incineration section, and by using combustible waste as an auxiliary fuel instead of heavy oil, it is possible to eliminate sludge without using heavy oil at all. An object of the present invention is to provide a dry incineration method that allows dry incineration.

That is, the present invention involves supplying wastewater treatment sludge alone or a mixture of combustible waste to a drying section of an incinerator for drying, and mixing the dried sludge, wastewater treatment sludge, and combustible waste and supplying the mixture to an incineration section for incineration. This is a method for drying and incinerating wastewater treatment sludge.

The present invention incinerates the combustible waste (C) with auxiliary combustion, and then uses the exhaust heat of the incineration section (8) to produce a drying section (
The sludge is dried in step 2), and the dried sludge (B) is transferred to the incineration section (step 3).
) is a method that allows efficient combustion and incineration.

An embodiment of the present invention will be explained with reference to FIG.

Wastewater treatment dewatered sludge (AI), such as coagulated sedimentation and activated sludge, which has been dehydrated to 80 to 85% moisture in the dehydrator (8), is transported to the mixer (4) using a comper or the like to be mixed with combustible waste. Ru.

The mixed sludge is supplied to the drying section (2) through the supply port (5) and dried by the combustion gas from the incineration section (8).

The dehydrated sludge supplied to the drying section may be supplied alone, but if combustible waste is mixed with it, it will have better contact with the exhaust gas and drying will be carried out more effectively.

The mixer (4) is not particularly limited as long as it mixes dehydrated sludge and combustible waste effectively.

The dried sludge (B) that has been dried in the drying section (2) has a moisture content of 10 to 15% and is transported to the mixer (6) to be mixed with the dehydrated sludge (A,) and combustible waste (Q). It will be done.

Combustible waste (Q can be any combustible material such as wood bark, wood chips, paper scraps, cloth, etc.) These also do not cause any problems in the mixer (6) or supply port (7). Any shape is acceptable, and it is preferable to use a screen such as a vibrating screen to sort out the size of the combustible waste (To).
In that case, conveyance to the mixer (6) using a screw conveyor or the like is optimal. The mixture supplied to the incineration section (8) from the supply port (7) is incinerated by auxiliary combustion of combustible waste.

In the incineration section, the sludge is incinerated at a maximum temperature of 800 to 1000°C, and this exhaust gas is used as a heat source for drying the sludge in the drying section.

The ratio of dehydrated sludge supplied to the drying section (2) and the incineration section (8) is preferably A, :A, = 20:80 to 50:50 bone dry weight%, and the supply to the drying section (2) is 20 bone dry weight%. If the amount is less than 50% by weight, the incineration in the incineration section is not good, and if it is more than 50% by weight, the drying in the drying section is insufficient. Undesirable.

The ratio of sludge and combustible waste in the mixer (6) is 1.
:(C!1=40:60~60- : 40 bone dry weight%
is preferred. If the amount of combustible waste CQO is less than 40% by bone dry weight, the sludge cannot be completely incinerated, and if it is more than 60% by bone dry weight, it is energy uneconomical.

The incinerated ash from the incineration section (8) is transferred to the conveyor into the hopper (
zt).

After being discharged from the drying section at a temperature of 250 to 800°C, the waste is discharged into the atmosphere through a chimney (14) through a water scrubber (12) and an exhaust fan (18).

Examples according to the present invention were carried out under the following conditions, and the conditions and results are shown in Table 1.

Table 1 It goes without saying that according to the method based on the present invention, combustible waste can be assisted in combustion, and drying and incineration can be carried out in one continuous facility without using any heavy oil. Since the heat generated by combustion can be effectively used in the drying section and the incineration section, it is of great value industrially and economically.

[Brief explanation of drawings]

A/, A, , A, : Activated sludge and coagulated sedimentation sludge B: Dry sludge C: Combustible waste 1: Incinerator 2: Drying section 8: Incineration section 4: Mixer 5: Supply port 6: Mixer 7 : Supply port 8: Dewatering machine 9: Vibrating screen 10: Screw conveyor 11: Hopper 12: Scrubber 18: Exhaust fan 14: Chimney Procedure amendment (method) Date: December 11, 1930 Director-General of the Patent Office Kazuo Wakasugi 2 , Title of the invention 11 To Mizumata 5)! 3,
Relationship with the case of the person making the amendment Patent Applicant 4, agent Address: Mitsubishi Paper Mills Co., Ltd., 3-4-2 Marunouchi, Chiyoda-ku, Tokyo 100, Japan Telephone: (213) 3641 March 29, 1964 (Issued) From 6, the number of inventions increases due to the amendment 8, the content of the amendment 1), Ming/1jlT 婁, the opening of the first page 411'. 4413)] Tetera 91-re schematic diagram. Enter 11 tsubo.

Claims (1)

[Claims] Waste water characterized in that wastewater treatment sludge alone or mixed with combustible waste is supplied to a drying section of an incinerator for drying, and dried sludge, wastewater treatment sludge and combustible waste are mixed and then supplied to an incineration section for incineration. Drying and incineration method of treated sludge.