JPH01266835A - Biological deodorizing method - Google Patents

Abstract

PURPOSE:To efficiently deodorize malodorous exhaust gas by coating a granular carrier of a hydratable polymer insoluble in cold water with a powdery inorg. substance, adhering microorganisms to the coated carrier, packing this carrier into a draft tube and passing the exhaust gas through the tube. CONSTITUTION:The granular carrier of a hydratable polymer insoluble in cold water such as PVA is coated with the powdery inorg. substance such as fine activated carbon powder. The coated carrier is immersed in a culture fluid contg. microorganisms such as sludge digesting night soil to adhere the microorganisms to the carrier. This carrier is packed into the draft tube and malodorous exhaust gas contg. methylmercaptan, methyl sulfide, etc., is deodorized by passing through the tube.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for biologically decomposing and deodorizing malodorous gases generated from various factories or processing facilities.

(Prior Art) Bad-smelling gases containing various organic or inorganic components are generated from sewage treatment facilities such as sewage treatment plants and human waste treatment plants, and from various factories such as pulp factories and fertilizer factories.

Therefore, as a conventional deodorizing measure, the odor emission intensity is generally
R (0dor Emission Rate) Geometric mean value: 1.7X 106Nrrf /min For putrid odor, chemical cleaning method, combination of oxidizing agent and activated carbon,
Alternatively, a direct combustion method is applied, and in the case of about 5×107, in addition to the direct combustion method, a combination of ion exchange resin and activated carbon adsorption is used.

Furthermore, even if the concentration of odor is as low as OE R2.7X 106 to 5.5X 10', the combustion method or chemical cleaning method is not effective when the amount of emissions becomes large, so activated carbon adsorption method is usually used. However, this method has the disadvantage that low-molecular-weight odor components such as ammonia, hydrogen sulfide, and methylamine cannot be adsorbed sufficiently.

Furthermore, each of the above-mentioned treatment methods requires high costs, and in particular, the activated carbon adsorption method has a problem of regenerated walls after breakthrough.

Recently, biological deodorization methods have attracted attention in hopes of reducing treatment costs, and attempts have been made to use soil or compost. However, due to the high airflow resistance, there is a limit to the height of the pile, and therefore a large area is required. Not suitable for exhaust treatment.

(Purpose) The present invention has an odor emission intensity○ER of 105 to 108 Nn (7
The purpose of the present invention is to provide a deodorizing method that can economically treat large quantities of malodorous gases.

(Structure) In the present invention, a water-containing polymer insoluble in cold water is molded into granules with a particle size of 5 to 15 mm with low ventilation resistance7, and a sufficient amount of neutral inorganic fine powder is attached to the surface of the granules. The coated material is used as a carrier.

Examples of water-containing polymers that are insoluble in cold water include completely saponified polyvinyl alcohol, saponified copolymers of vinyl acetate and acrylic monomers and/or vinyl ethers, graft compounds of polyvinyl alcohol and acrylic monomers, acrylic polymers, urethane, and water. These include crosslinked products of soluble polymers.

In addition, the fine inorganic substance for coating includes various inorganic substances such as almost neutral soil, kaolin, and talc that do not inhibit microorganisms, but preferably activated carbon fine powder or zeolite fine powder with chelating effect is used. This prevents blocking during storage after carrier production or blocking due to automatic compaction of the deodorizing layer.

The water-containing polymer described above has the effect of imparting appropriate humidity to the inorganic powder on the surface of the carrier, promoting the growth of microorganisms, and facilitating the diffusion of malodorous components that come into contact with it.

It also has the effect of smoothing the neutralization reaction of oxidized substances produced by adsorption or biodegradation.

*In the present invention, the carrier particles are added to a culture solution containing microorganisms in which microorganisms that act on deodorization are cultured in liquid, or to a solution containing microorganisms that act on deodorization in advance, by utilizing the expansion effect of carrier particles as the polymer absorbs water. By dipping the particles,
When water is absorbed, microorganisms in suspension are easily adsorbed and immobilized on the surface of carrier particles.

The water content of the polymer carrier can be adjusted by sprinkling water while monitoring the decrease in the filling volume due to shrinkage of the carrier when the water content decreases.

(Example) In a cylindrical column with a diameter of 150 m + n x height of 200 + um, finely powdered activated carbon-coated granules of polyvinyl alcohol with an average particle size of about 10 mm were soaked in human waste digested sludge for a day and a night after 1-1.
It was filled to a depth of 150 mm. (Filled bed fit2.65ffl
) Air containing 5 ppm each of methyl mercaptan and methyl sulfide was passed through the 5V501 for 1 week, and it was confirmed that the discharged air did not contain methyl mercaptan or methyl sulfide, and acclimatization was completed.

Thereafter, after aeration for 5 days, both components were not detected in the exhaust gas, and it was confirmed that both components were adsorbed and removed. Next, air containing 10 Ppm of methyl mercaptan was applied at 5 V.
Although aeration was carried out at 200 Hr-' for one month, no malodorous components were detected in the exhaust gas, indicating that the components were biodegraded.

As a result of adsorption and biooxidation of the contained components, the surface of the carrier becomes acidic. In order to neutralize this, a potassium phosphate buffered aqueous solution was sprayed from above the cylindrical column once a day.

(Comparative Example 1) A column similar to that in the example was filled with peat moss from the same day as in the example, and the same acclimatization was performed by spraying the unprocessed sludge after neutralization with lime, but the same performance was obtained. It took two weeks.

Thereafter, when the ventilation amount was increased to 5V120Hr-', approximately ippm of methyl mercaptan remained in the exhaust gas, and the same effect as in the example could not be obtained.

(Comparative Example 2) A carrier molded with fly ash similar to that of the example was filled in a column similar to that of the example by soaking it in human waste digested sludge for a day and night, and then the same acclimatization was performed, but the same performance was obtained. It took two weeks to get it.

Thereafter, air containing 10 ppm of methyl mercaptan was vented at 5 V and 100 Hr as in the example, but methyl mercaptan and methyl sulfide were detected in the exhaust gas at several ppm, and the same effect as in the example could not be obtained. In this case, it was necessary to constantly shower the packed bed with a pump to prevent the carrier from drying out.

(Effects) The granule carrier of the present invention has low ventilation resistance in the packed cylinder and can vent multiple times per hour.

In addition, since it is granular and the degree of non-uniformity of each sphere is large, the microbial habitat and gas contact surface area are also large, which shortens the microbial adaptation period and enables high processing capacity.

Furthermore, since the carrier is composed of a water-containing polymer, it is easy to provide or adjust humidity to inhabit microorganisms.
It can be expected to have great economic effects, such as reducing running costs and eliminating the need for regeneration, which was the biggest problem with conventional methods.

Furthermore, by utilizing a method of immobilizing microorganisms on the carrier surface by the action of a polymer carrier that absorbs a large amount of water accompanied by swelling,
It becomes easier to use microorganisms with a deodorizing effect by immobilization, and it also becomes possible to use microorganisms obtained by liquid culture by immobilization.

Furthermore, the amount of microorganisms immobilized on the carrier surface can be easily adjusted.

Since the void ratio when filling the carrier particles is large, the pressure loss during ventilation is small, and energy saving can be achieved.

Patent applicant Denka Engineering Co., Ltd. Hitoshi 1) Hiroshi Agent Patent attorney Hiroshi Nakamura

Claims (1)

[Claims] 1. A biological deodorizing method, which comprises filling a cold water-insoluble granular water-containing polymer carrier coated with a powdery inorganic substance in a ventilating cylinder, acclimatizing it to microorganisms, and then aerating foul-smelling exhaust air through the packed bed.