JPH0636852B2 - Sludge deodorizer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sludge deodorizing device, and in particular, a sludge deodorizing device capable of obtaining a stable deodorizing effect even when a high concentration odor is generated temporarily. Regarding

[Prior Art and Prior Art] In the sludge treatment process, a deodorant is injected in order to suppress the generation of malodorous gas containing H ₂ S as a component to be below the working environment standard. As a method for injecting the deodorant, a quantitative chemical injection has been conventionally performed in which the deodorant is added at a constant ratio with respect to the amount of sludge.

However, in this method, the injection amount of the deodorant is set regardless of the generation state of the odor, so that the amount of the deodorant used is unnecessarily increased and the chemical cost increases, and the deodorant is also added. In some cases, it may not be possible to prevent the generation of foul odor due to lack of
There were administrative and economic problems.

Therefore, the applicant of the present invention automatically measures the odorous gas component in the processing gas with a gas sensor, automatically calculates the chemical injection amount according to the measured gas concentration, and automatically dispenses chemicals. And applied for a patent first (Japanese Patent Application No. 63-2
Nos. 72709 to 63-272712), an excellent improvement effect could be obtained.

[Problems to be Solved by the Invention] However, in the above feedback control system in which the odor of the processing gas is measured and then the amount of chemical injection is calculated to perform chemical injection, a bad odor is sufficiently prevented from occurring due to control delay. You may not get it.

That is, for example, when the sludge dewatering process is restarted after a certain rest period, the sludge left in the sludge storage tank without being processed in the previous process for a certain period is sent to the dewatering process at the beginning of the process. Is coming. This sludge (hereinafter referred to as “initial sludge”) has been rotted during the rest period stored in the storage tank, that is, between the end of the previous treatment and the start of this treatment. It produces odorous gas containing a high concentration of odorous components.

In the initial stage of resuming the treatment when such initial sludge is sent, the amount of deodorant required to prevent foul odors is delayed due to the time delay in feedback control from measuring the generated odorous gas component to performing chemical injection. It was not possible to prevent the generation of offensive odor.

It is an object of the present invention to provide a sludge deodorizing device having an automatic deodorant chemical dosing control system capable of solving the above-mentioned problems caused by a time delay in feedback control and always obtaining a stable deodorizing effect. To do.

[Means for Solving the Problems] The sludge deodorizing apparatus of the present invention is a deodorant storage tank, a gas sensor that detects the concentration of odorous components generated from sludge, and an operation unit to which a detection signal from the gas sensor is input. And a chemical dosing pump for controlling the dosing amount of the deodorant supplied from the storage tank to the sludge based on the signal output from the computing unit, wherein the computing unit is It is characterized in that a chemical injection control signal capable of responding to the maximum concentration of odorous gas that can be generated is output for a predetermined period, and after the period has elapsed, a signal according to the signal input from the gas sensor is output.

[Operation] In the sludge deodorizing apparatus of the present invention, the following signal A or B is output from the calculation unit.

A. Certain control signals B. A signal according to the signal input from the gas sensor, that is, the A signal for a certain period, and the B signal after that.
Output a signal.

Therefore, for example, by performing the following control,
It is possible to reliably prevent the generation of a bad odor. That is, as the A signal, a chemical injection signal that can correspond to the maximum concentration of odorous gas that can be generated from sludge is set and input. Also, as a certain period of time for outputting the A signal, the time required for almost all of the initial sludge to be sent to the dehydration process after the start of the dehydration process, or the new sludge sent to the sludge storage tank due to the start of this process. Therefore, the time required for reducing the influence of the initial sludge on the odor generated in the dehydration process is set.

Thus, the dehydration process is restarted, the period during which the initial sludge that generates odorous gas containing an odorous component in high concentration is fed to the dehydration process or the period during which high concentration odorous gas is generated in the dehydration process by the initial sludge, The arithmetic unit outputs a chemical injection signal that can correspond to the maximum concentration of odorous gas that can be generated from sludge as the A signal regardless of the detection signal of the gas sensor. For this reason, a large amount of deodorant is supplied by the chemical injection pump, the time delay in feedback control that performs chemical injection control based on the detection signal of the gas sensor is eliminated, and the high concentration odor gas of the initial sludge is eliminated. The bad smell caused by is surely prevented.

In the present invention, there is no particular limitation on the set value of the A signal or the period for outputting the A signal, which is set in the calculation unit, and is appropriately determined according to the type of the sludge treatment process for setting the sludge deodorizing device and the like. . That is, for example, regarding a treatment process in which sludge that generates a high-concentration odorous gas may be sent other than when the treatment is restarted, a large amount of chemical injection preset as the A signal is instructed to the chemical injection pump for that period. It is possible to output a medicine injection signal (hereinafter, referred to as a “large quantity medicine injection signal” and a signal instructing a small quantity medicine injection is referred to as a “small quantity medicine injection signal”). On the contrary, when sludge that generates low-concentration odorous gas is sometimes sent in, a small amount chemical injection signal preset as the A signal can be output during that period. It is also possible to set both a large amount medicine injection signal and a small amount medicine injection signal as the A signal, and to output each signal during a certain set period.

Further, the period for outputting the large-volume drug injection signal or the small-volume drug injection signal is not limited to one set in time as a preset period, until the detection value of the gas sensor exceeds a certain concentration, or It can also be set based on the concentration range of the odorous gas detected by the gas sensor, such as until the concentration becomes below a certain concentration.

As described above, according to the device of the present invention, it is possible to prevent excess or deficiency of the deodorant and to perform good chemical injection control.

Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a system diagram showing an example in which a sludge deodorizing apparatus according to an embodiment of the present invention is applied to a sewage sludge dewatering process.

In FIG. 1, sludge is fed and stored in a sludge storage tank 1 through a pipe 11. The sludge in the sludge storage tank 1 is sent to a dehydrator 3 through a pipe 12 equipped with a mud supply pump 2 to be dehydrated, and a dehydrated cake is discharged through a pipe 13. Plumbing 12
A pipe 14 having a chemical injection pump 5 for chemical injection of the deodorant in the deodorant tank 4 is connected to the.

In this embodiment, the dehydrator 3 is a source of bad odor. A gas sensor 6 is installed in the vicinity of the dehydrator 3, and the detection value of the gas sensor 6 is input to a calculation unit 8 via a signal processing unit 7. In addition, a synchronization signal for notifying the operating state of the dehydrator is input to the calculation unit 8. This sync signal is
For example, it is a signal representatively indicating the start or stop of the operation of the dehydrator, and specifically, a signal reporting the operating state of the mud pump or the operating state of the dehydrator. The arithmetic unit 8
Is composed of, for example, a microcomputer, and is capable of various arithmetic processing and time series processing by an internal timer.

In the sludge deodorizing apparatus of this embodiment, when the dehydrator 3 in the dehydration process, which is a control target, starts to operate and starts the dehydration process, a synchronization signal notifying the start of the process is input to the calculation unit 8. The arithmetic unit 8 receives the synchronization signal and outputs a drug injection signal to the drug injection pump 5 to start the drug injection control. At that time, a fixed period from the start of the process (this period is fixed as described above). Of the gas sensor 6 or a period until the detection value of the gas sensor 6 becomes a certain concentration or less) may be set in advance regardless of the detection signal input from the gas sensor 6. The generated medicine injection signal (in this case, a large quantity medicine injection signal) is output to the medicine injection pump 5, and a large amount of deodorant is supplied. And after the lapse of the certain period,
Based on the detection signal input from the gas sensor 6, the medicine injection signal calculated from the detection value is output.

Thus, during the period when a high-concentration odorous gas due to the initial sludge is generated, instead of feedback control, based on a preset large-volume dosing signal, by dispensing a large amount of deodorant, It is possible to reliably prevent the bad odor caused by the initial sludge.

It should be noted that the example shown in FIG. 1 is one embodiment of the present invention, and the present invention is not limited to the illustrated one as long as it does not exceed the gist of the present invention. Needless to say, other modes can be adopted.

[Effects of the Invention] As described in detail above, according to the sludge deodorizing apparatus of the present invention, it is possible to always stably and reliably prevent odors generated from sludge efficiently by automatic control.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the sludge deodorizing apparatus of the present invention. 1 ... Sludge storage tank, 2 ... Mud pump, 3 ... Dehydrator, 4 ... Deodorant tank, 5 ... Chemical injection pump, 6 ... Gas sensor, 7 ... Signal processing unit, 8 ... … Calculator.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-63-151400 (JP, A) JP-A-2-119997 (JP, A) Iitani et al., “Basics of Process Control,” Asakura Shoten, page 163, page 22 Line-Page 164 Line 12

Claims (1)

[Claims] 1. A deodorant storage tank, a gas sensor for detecting the concentration of odorous components generated from sludge, an arithmetic unit to which a detection signal from the gas sensor is input, and a signal output from the arithmetic unit. A sludge deodorizing device comprising: a chemical pump for controlling the chemical injection amount of the deodorant supplied from the storage tank to the sludge, wherein the computing unit can correspond to the maximum concentration of odorous gas that can be generated from the sludge. A sludge deodorizing device, which outputs a chemical injection control signal for a predetermined period and, after the period has elapsed, outputs a signal according to a signal input from a gas sensor.