JPS6025595A - Treatment of organic sludge - Google Patents

Abstract

PURPOSE:To treat an organic sludge while conserving energy, by a method wherein a fibrous material such as papers is added to a portion of an organic sludge, which is then dehydrated by a dehydrator and is incinerated, and a dehydrated cake derived from the remainder of the organic sludge is dried by heat of combustion generated by the incineration. CONSTITUTION:A sewage sludge 2 is apportioned from a sewage sludge 1, a fibrous material 3 such as used newpapers is added to the sludge 2, and after mixing, a dehydration adjuvant 4 such as a polymer is added thereto as required, and the resultant mixture is separated into a dehydrated cake 6 having a water content of 40-50% and dehydration-derived water 7 by a screw press dehydrator 5. The dehydrated cake 6 is introduced into an incinerator 8, and is incinerated to obtain combustion heat 9. The remainder 2' of the sludge 1 is dehydrated by an arbitrary dehydrator 11 to obtain a dehydrated cake 12 and dehydration-derived water 13. The cake 12 is dried by the combustion heat 9 in a drying chamber 14 to obtain a dried material 15, which has a low water content of not more than 10%, and can be effectively utilized as a fuel.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Description of the Technical Field The present invention relates to a process for treating organic sludge generated from organic sewage treatment facilities such as sewage treatment plants and human waste treatment plants.

2. Description of the Prior Art The dewatering and drying process of organic sludge has been widely recognized as an energy-intensive process, and there is a strong desire to develop an energy-saving process.

Conventional technology uses polymers, FeC15, Ca(
The process involves adding a dehydration aid such as OH) and dehydrating it in various dehydrators, and then consuming auxiliary fuel such as heavy oil or city gas to dry the dehydrated cake.

3. Purpose of the present invention The purpose of the present invention is to provide an energy-saving organic sludge treatment process that does not require any auxiliary fuel for drying the dehydrated cake.

4. Structure of the Invention The present invention extracts a part of the organic sludge supplied to the dehydration process, adds and mixes fibrous material such as paper to the dispersed sludge, and dehydrates it using a screw press dehydrator to obtain a dehydrated cake. This is a method of self-combusting and drying a dehydrated cake obtained by dewatering the remainder of the organic sludge using an arbitrary dehydrator using the heat produced by the combustion.

5. Uniqueness and novelty of the technical idea of the present invention The present invention involves separating a part of organic sludge and rationally reducing it in order to rationally utilize the calorific value of organic sludge itself. The technology is unique and novel in that it dehydrates the organic sludge to water and uses the high calorific value of this dehydrated product to dry the remaining organic sludge and turn it into fuel without using auxiliary fuel.

6. Embodiments of the Invention An embodiment of the invention will be described along with its operation with reference to the drawings.

A part of the sewage sludge 2 was separated from the sewage sludge 1, and fibrous materials 3 such as old newspapers, residue, sawdust, and rice husks were added and mixed (usually 10 to 30% by weight of the sludge solid content). Afterwards, if necessary, add a dehydration aid 4 such as a polymer, and use a screw press dehydrator 5 to reduce moisture content (water content 40-50).
%) is separated into a dehydrated cake 6 and dehydrated separated water 7. In addition, 16 is a stirring tank.

The dehydrated cake 6 has a low moisture content and can be easily self-combusted, so it is incinerated in an incinerator (or pyrolysis furnace) 8 (in the present invention, the term "incineration" is used to include pyrolysis). ) and obtain combustion generated heat 9.

Note that the dehydrated cake 6 may be incinerated after passing through the drying step 10. The heat source for this drying uses the retained heat of the air discharged from the aeration blower (temperature has risen to 70-90°C) to supply air to the aeration tank in the biological treatment process for organic wastewater such as sewage. By doing this, you can dry without using fuel.

According to this method, the calorific value of the dry matter to be incinerated becomes very large, so that a large amount of combustion generated heat 9 can be recovered.

The remaining sewage sludge is then dehydrated by an arbitrary dehydrator 11 to form a dehydrated cake 12 and dehydrated separated water 16.

Note that any type of dehydrator 11 can be used, but among them, one that can perform dehydration at high squeezing pressure, such as a filter press or a scree press, is preferable. Dehydrated cake 1
The moisture content of Cake 2 is usually higher than that of Dehydrated Cake 6.

The dehydrated cake 12 is dried in the drying chamber 14 by the combustion generated heat 9 to obtain a dried product 15. The dry material 15 has a low moisture content of 10-10 or less and has a high calorific value, so it can be effectively used as a fuel for various industries.

7. Functions and Effects of the Invention ■ Organic sludge can be made into a dry product with low moisture content without using any auxiliary fuel such as heavy oil, and this dry product can be effectively used as a fuel.

■ Since fibrous material such as paper only needs to be added to a portion of the organic sludge, the amount of paper used can be reduced.

(2) The profit obtained by selling the dried product 15 of the dehydrated cake 12 obtained from the dewatering step (11) as fuel can cover the cost of purchasing paper, etc., so the operating cost of the sludge treatment step can be further reduced.

■ In addition to the effect of significantly reducing the moisture content of the dehydrated cake of the screw press dehydrator by adding paper, etc., the calorific value of the dehydrated cake increases due to the coexistence of paper, so the remaining organic sludge (2') A larger amount of drying heat can be obtained.

[Brief explanation of the drawing]

The drawing is a flow sheet of an embodiment of the present invention. 1.2.2'... Sewage sludge, T... Fibrous, 4...
Dehydration aid, 5... Screw press dehydrator, 6, 12
...Dehydrated cake, 7,13...Dehydrated separated water, 8...
・Incinerator, 9... Combustion generated heat, 10... Drying process,
11... Dehydrator, 14... Drying chamber, 15... Dry material, 16... Stirring tank. Patent applicant: Patent attorney representing Ebara Infilco Co., Ltd.
1,000 1) Twisting Takao Maruyama

Claims (1)

[Scope of Claims] 1. Fibrous materials such as paper, sludge, sawdust, and rice husks are added and mixed to a part of the organic sludge, dehydrated in a screw press dehydrator, and then incinerated in the incineration process; A method for treating organic sludge, comprising treating the remainder of the organic sludge with an arbitrary dehydrator to form a dehydrated cake, and drying the dehydrated cake using the heat generated by combustion in the incineration step. 2. The dehydrated cake produced by the screw press dehydrator is dried by the heat retained in the discharged air of a gas blower that supplies air to an aeration tank in a biological treatment process for organic wastewater, and then incinerated. the method of.