JPS62121699A - Method for deodorizing dehydrated cake - Google Patents

Abstract

PURPOSE:To prevent the generation of a malodor coming from the surface of a dehydrated cake, by scattering a solid compound generating active oxygen to the surface of the dehydrated cake. CONSTITUTION:Sewage and org. Substance-containing industrial waste water are biologically treated and dehydrated to obtain a dehydrated cake with water content of about 75%. A solid compound generating active oxygen such as calcium peroxide or magnesium peroxide is scattered to the surface of the dehydrated cake. Active oxygen oxidizes a malodorous component such as hydrogen sulfide generated from the dehydrated cake and markedly prohibits the activity of anaerobic bacteria causing a malodor and suppresses the formation of sulfide. By this method, the deodorizing of the dehydrated cake and the regeneration of the malodor can be prevented.

Description

[Detailed Description of the Invention] Industry - 1 - Field of Application The present invention is directed to 1. The field of application of industry - 1 - generated when water and industrial wastewater are treated.
This invention relates to a deodorizing method for dewatering cake 1', which makes the dewatering cake of 47+16 mud non-fading and prevents the recurrence of bad odor over a long period of time.

Conventional technology Sewage and industrial wastewater containing organic matter (hereinafter referred to as sewage, etc.)
9 Usually, it is purified through physical and biological treatment, which generates a large amount of sludge. The sludge is
The sludge is once sent to a sludge storage tank, where a dehydration aid is added, and then dehydrated to form a dehydrated cake with a moisture content of around 75%, which is then disposed of in a landfill or incinerated.

Since there is no dissolved oxygen in the sludge, odorous substances containing sulfur or nitrogen that quickly generate unpleasant and toxic odors due to the activity of anaerobic bacteria9 For example,
Generates hydrogen sulfide, mercaptan, ammonia, etc.
The generation of this foul odor is an extremely serious problem for treatment plant workers and local residents.

As a countermeasure, 1. A method of adding hydrogen peroxide and treating sludge with hydrogen peroxide was proposed, and this method
Because it can reduce the occurrence of bad odors inside the dehydrator room,
This is an extremely advantageous method for deodorizing sludge.

However, the dehydrated cake that has been dehydrated may be piled up in the open for about 48 hours before being taken out of the treatment plant by truck etc. for disposal. At this time, the dehydrated cake will generate a bad odor again, so deodorizing the dehydrated cake In this sense, the situation is unsatisfactory, and drastic solutions are urgently needed to address the complaints of local residents and improve the working environment.

Problems to be Solved by the Invention The present inventors have dehydrated cake to be odorless and at the same time prevent the reoccurrence of bad odors even if the dehydrated cake is stored in the open for a long time before being transported outside the treatment plant. About how to
As a result of intensive studies, two inventions have been achieved.

Means for Solving the Problems (2) The present invention is a dehydration method characterized in that a solid compound that generates active oxygen is sprayed on the surface of a dehydrated cake to make the cake odorless and at the same time prevent the reoccurrence of bad odors. Concerning how to deodorize cake.

In the present invention, solid compounds that generate active oxygen (hereinafter referred to as active acid The amount of soda percarbonate to be sprayed varies depending on the sulfide concentration in the dehydrated cake, and cannot be determined in general terms, but it is desirable to spray it evenly over the surface of the cake.

Hydrogen peroxide, a liquid compound that generates active oxygen, is extremely effective at the initial stage of spraying, as shown in Example 1, but has no effect at all in suppressing the reoccurrence of bad odors over time. [Although it is inappropriate to use the active oxygen supplying agent of the present invention], prior to the present invention, adding hydrogen peroxide to sludge can suppress the generation of bad odors in the dehydrator room, so it can be used for sewage, etc. It is possible to improve the working environment from the dewatering of sludge to the disposal of the dehydrated cake in the process.

Function: The active oxygen supplying agent of the present invention decomposes into 9 to generate active oxygen. This active oxygen has the effect of oxidizing the bad odor such as generated hydrogen sulfide, and at the same time has the effect of suppressing the production of sulfide because it significantly inhibits the activity of anaerobic bacteria that cause the bad odor.

In the present invention, the active oxygen supplying agent sprayed on the surface of the dehydrated cake deodorizes the bad odor generated from the cake surface, and some of it also gradually penetrates into the cake and acts as an anaerobic agent that causes the bad odor. It is considered that the dehydrated cake can be made odorless and the reoccurrence of bad odors can be prevented by inhibiting the activity of sexually transmitted bacteria.

The invention effectively deodorizes bad odors and inhibits the activity of anaerobic bacteria that cause bad odors, so even if dehydrated cakes are left in the open for a long time, the bad odors can be prevented from reoccurring. This is a fundamental solution to the complaints of local residents and the working environment of the treatment plant.

Example The present invention will be explained below using examples.

A dehydrated cake (moisture content: 789
6) was used as a test cake, 500f of the dehydrated cake was placed in a 5/2-inch plastic bottle, and the prescribed bar of each chemical shown in Table 1 was sprinkled on the surface of the dehydrated cake. Odor concentration (three-point comparison mounting method) was measured for each.

As a result, 1st Note) PC is an abbreviation for soda percarbonate and effective oxygen z3
．． A 55A product was used.

■ For Cα02, a product with 7% effective oxygen was used.

■ Items marked with an X are comparative examples.

Nippon Peroxide Co., Ltd.

Claims (1)

[Scope of Claims] A method for deodorizing a dehydrated cake, which comprises spraying a solid compound that generates active oxygen on the surface of the dehydrated cake to make the cake odorless and at the same time prevent the recurrence of bad odors.