JPS6061097A - Controlling method of air supply in composting process - Google Patents

Abstract

PURPOSE:To enable the control of air supply showing ideal fermentation progress by obtaining a necessary supply amt. of air to get the desired temp. from a relational expression between the fermentation temp. and the ratio of air supply to residual BOD and the value of desired temp., and controlling the supply. CONSTITUTION:The weight, water content, and BOD5 when the starting material is thrown in are obtained. The initial set value of air supply is then calculated by using the previously obtained relational expression. The desired temp. at this time is preferably regulated to about 70 deg.C. After the staring material is thrown in, the fermentation is started by regulating the air supply to said value. The air supply and the CO2 concn. are measured continuously or at every specified period of time after the fermentation is started. After apecified hours, the CO2 amt. generated during the specified hours is obtained by integration from the measured values of air supply and CO2 concn. Said operation are repeated at every predetermined time, and the control of air supply showing ideal fermentation progress can be realized.

Description

[Detailed Description of the Invention] The present invention provides a method for controlling the amount of aeration to efficiently process various types of q) sludge, etc. in a congesting process in which sludge, etc. is subjected to aerobic fermentation treatment by controlling the amount of aeration. Regarding q).

BOD in fermentation raw materials in an experiment in which sewage sludge and other various sludges and common wastes are aerobically fermented, that is, composted.
It was found that the ratio of the aeration amount to the total amount was closely related to the fermentation temperature.

Therefore, if the total BOD at each time can be known, the ventilation t required to maintain the target fermentation temperature can be determined.

However, since B ODail#'i cannot be measured immediately,
It has to be estimated somehow. Airflow and 00
Decomposed BODI based on the amount of GO2 generated based on the change in temperature of 29 degrees.
Relationship with I'5! - Upon investigation, a close correlation was found between the two. Based on the above, F1 ventilation amount and CO2 concentration? The change in the total amount of BOn is estimated by observing the amount, and the amount of ventilation/
It became possible to adjust the aeration amount to an appropriate level based on the relationship between the BODa amount and the completion fermentation temperature.

The present invention was made by paying attention to the point S, and in the process of converting organic waste such as sewage sludge and livestock waste, CO2 generation is calculated from the ventilation amount and 002°C, and GO2 BOD from the equation of occurrence risk and BOD decomposition amount
1 ton of decomposition, and the remaining BODw#, ventilation fi/
This method is characterized in that the amount of ventilation required to reach the target temperature is determined from the relational expression between the BOD residual value and the fermentation temperature and the value of the target temperature, and the amount of ventilation is controlled.

The present invention will be explained in detail below based on illustrated embodiments.

The first prevention is BODi (x) decomposed and 00 generated during the process of adding rice husks to sewage sludge and composting it.
This shows the relationship between two horses (y). In other words, the relationship between the amount of BOD decomposed (x) and the amount of CO2 generated (y) has an extremely high correlation as the correlation coefficient is 0.98, which is close to 1. In the case of this raw material, ytsuQ, l, 9 ') x 1・
The following relational expression holds true. The constants ^ and b in y-B, z, and b are somewhat different depending on the fermentation raw material l, but a
, the total amount of CO2 heat generated up to a certain time can be calculated from the changes in ventilation volume and CO2 concentration over time, so the relational expression y −1 @ , z b 1! r
- The total BOD decomposed using -tit (x) Th, can be estimated. Furthermore, from the initial BODlpl calculated from the weight at the start of fermentation and the analysis value of moisture content BOD5, the remaining /:t ROD amount (Z)' at a certain time
fr - calculate.

On the other hand, from many composting experiments, the airflow rate/BO1f
The relationship between t(Q/Z) and fermentation temperature It' (T) is T-C
(It was found that it is expressed by the relational expression Q/Zld. In this case, the constant@0.d fermenter causes some R, but the stiffness depends on the heat insulation of the main S. (7) If o and d are set in advance, the aeration amount (Q, 1) required to achieve the appropriate fermentation temperature (TI) at a certain time I is determined by the amount of air remaining at that time. BO to do
It can be calculated from Dli(Z) and the relational expression T=C(Q/Zld).

For example, in a small fermenter with a tank volume reduction of 3 m%, T = IF.
+4(q/Z)-0,59 relational expression is obtained.

The above ventilation amount control method will be explained by breaking it down into 70 sheets as shown in tR2 FIG.

First, record the weight, moisture content, and Boas of the raw materials at the time of input. This includes input raw materials /) BOD total EN (Z
o)? If the value is for calculation and can be sufficiently estimated from past data, it may be an estimated value.

Next, when calculating the initial ventilation rate set value Qo'f/ using the relational expression T-C(q/Z]d prepared in advance, the target temperature TQ is preferably about 70°C.

After adding the raw materials, fermentation is started by setting the aeration amount to Qo. Continuously or for a certain period of time 11f after the start of fermentation
Measure ventilation 1 and CO2 concentration every t intervals. Fixed time 11
After υ(tl) has elapsed, calculate the amount of coz (yl) that has occurred within 31 hours using the ridge number from the actual measured values of the ventilation amount and CO2m% degree.

According to the present invention, the amount of Co2 generated (y) and the amount of BOD decomposed (X
), since there is a relationship, the BOD decomposition @X1 for 711 is calculated using a predetermined relational expression. At this time, B ODij Zl l'i, Zl-ZO-XI remaining in the raw material
becomes.

Next, at this time, +7(j) is set to satisfactorily eyesight temperature T1, and the relational expression T=C(q/Zld is used to calculate an appropriate ventilation amount Q1, and the ventilation amount is changed from qo to qi l).

[Above] At the predetermined time of the operation, the ventilation waste control is completed. Also, put the rod 2 and 1 for ventilation! ,
It is desirable to automatically control the progress of fermentation by connecting an automatic CO2 concentration recording device to an aeration rate system and a microcomputer.

The present invention has the advantage that various types of sludge can be subjected to efficient and ideal fermentation treatment using a simple method.

[Brief explanation of the drawing]

The first drawing shows 5oots that were decomposed during the composting process.
Figure 2, a correlation diagram showing the relationship between 1 and the generated GO2 position, is a 70-sheet showing the ventilation amount control method of the present invention. Patent Applicant Hitachi Machinery and Electric Industry Co., Ltd. Kiyoshi Hayashi Mongai 1 person 1 drawing

Claims (1)

[Scope of Claims] (1) In the process of converting organic waste such as sewage sludge and livestock waste into a waste post, CD from the aeration layer and 002 concentration is
2 Calculate the amount generated, calculate the BOD decomposition and crushing from the relational expression between the amount of GO2 generation and the amount of BOD decomposed, and calculate the remaining BODMI from the relational expression between the aerator/ROD concentration and fermentation temperature and the value of the target temperature. Determine the amount of ventilation required to reach the target temperature of 1, and use ventilation jet control? A method for controlling the amount of aeration in a congosting process, characterized by carrying out atl. (21002' A method for controlling the amount of aeration in a composting process according to claim 1, characterized in that a formula is used for the relationship between decomposition and BOD decomposition. (3) Aeration Mt/remaining amount of BOD A method for controlling the aeration amount in the feces post-forming process according to claim 1, characterized in that the relational expression of the fermentation temperature is used. (4) A self-axis recorder for aeration amount and CO2 concentration, and a climate control device. 2. A method for controlling the amount of ventilation in a post forming process according to claim 1, characterized in that the setting of the amount of ventilation in the white layer T can be changed by using a microcomputer.