JP2010000423A - Wastewater treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method which efficiently decomposes and removes hardly decomposable substances by microorganisms, can be operated by existing facilities without requiring large equipment, and low in chemical cost and operating cost, and uses Pseudomonadaceae Pseudomonas sp. W-4 and Chryseobacterium Chryseobacterium sp. W-6 as the microorganism for decomposing the hardly decomposable substances to decompose PVA in a short time by an activated sludge treatment method, which is a biological treatment method. <P>SOLUTION: Two strains, Pseudomonadaceae Pseudomonas sp. W-4 and Chryseobacterium Chryseobacterium sp. W-6, found and isolated from an activated sludge tank in a bio-decolorization system for colored wastewater are cultured and added to the activated sludge tank, thereby reducing TOC and COD. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wastewater treatment method for decomposing a hardly decomposable substance using microorganisms.

In recent years, from the viewpoint of protecting the natural environment, a microbial treatment method with less energy loss and less sludge discharge has received much attention as a wastewater treatment method. However, there are many wastewaters that are not easily decomposed by microorganisms, including synthetic polymers. Even if a microorganism that degrades the substance to be treated is discovered and its ability is utilized in actual treatment, it is a very difficult problem to effectively express and maintain the resolution. A variety of substances are involved in the fiber dyeing wastewater, which is involved in COD, the wastewater standard of the Water Pollution Law. The COD source is said to be hardly degradable by the activated sludge method, which is a biological treatment method, and is said to be a hardly degradable substance.
Fiber dyeing wastewater has a process of bleaching and scouring the cloth to be dyed in the process before dyeing,
It is known that the COD source discharged from this bleaching and scouring process contains a lot of persistent substances. In the activated sludge treatment method, it is difficult to treat the COD source discharged from the bleaching / scouring process. In general, wastewater from the textile dyeing industry is drained from the scouring process, such as polyvinyl alcohol, polyacrylic acid, starch and other pastes, desizing agents, surfactants, and the like. From the dyeing process, reactive dyes, disperse dyes, Dyeing wastewater such as acid dyes, dyeing assistants, washing wastewater, and the like are discharged, and oil agent, thermosetting resin, thermoplastic resin, and the like are discharged from the finishing process. These wastewaters are often turbid liquids that are highly colored and have a high COD representing environmental impact. Polyvinyl alcohol (hereinafter referred to as PVA) is the main component of the COD source, which is discharged from the bleaching and scouring process, and is widely used as warping agents, adhesives, films and paper processing materials in the textile industry. ing.

A typical physicochemical treatment method for wastewater from the textile dyeing industry used in the past is a large amount of inorganic flocculants mainly composed of metal salts such as iron salts and aluminum compounds, and polymer flocculants such as polyacrylamide. In many cases, a combination of a physicochemical method such as coagulation sedimentation treatment or pressurized flotation treatment and a biological method such as activated sludge treatment is employed. However, in the physical method, environmental and health problems such as neurotoxin and carcinogenicity are pointed out to acrylamide monomer, which is an impurity contained in polyacrylamide. Further, since a large amount of flocculant is required, the cost of the flocculant is required, and agglomerated sludge and sludge generated in a large amount are discharged. At present, the agglomerated sludge and sludge are disposed of in landfills with dewatered cake dehydrated or partly incinerated. From now on, the price of the flocculant, the disposal cost of sludge / sludge, and the operating cost of wastewater treatment will become higher, making landfill disposal and incineration difficult. In the activated sludge method, the aeration tank in the activated sludge used has a growth rate even if there are bacteria capable of decomposing or assimilating PVA, a low ratio, or microorganisms assimilating PVA.・ Because the growth rate is very small, it is not efficiently treated and discharged as undecomposed during 24-hour residence in normal operation.

As other physicochemical methods of waste water containing PVA, it is treated by a bubble separation method, a coagulation precipitation method, an ultrafiltration method, an activated carbon adsorption method, a heavy metal chelate method, and the like. In the case of the activated carbon adsorption method, the amount of activated carbon consumed is enormous, and it is also expensive to recycle the activated carbon after use. On the other hand, wastewater treatment methods using microorganisms generally have many proposals for treatment devices such as biological treatment and activated sludge treatment, and few treatment methods specify microorganisms.

The technique described in Patent Document 1 includes a method for culturing a microorganism characterized by adding an enzyme capable of decomposing hydrogen peroxide to a medium, a specific organic compound, a microorganism decomposing the organic compound, and a decomposing ability of hydrogen peroxide. A composition comprising an enzyme having an enzyme, a cultured cell or component of a microorganism exhibiting the ability to oxidize or assimilate a specific organic compound, in the presence of an enzyme capable of decomposing hydrogen peroxide; And a method for decomposing the organic compound characterized in that it is a polyvinyl alcohol-assimilating bacterium having a deposit number of “FERM P-14773” and a polyvinyl alcohol-assimilating bacterium having a deposit number of “FERM P-14857”. Yes. The technique described in Patent Document 2 grows with polyvinyl alcohol as the sole carbon source, decomposes at least 40% of the added polyvinyl alcohol in an aerobic culture at 30 ° C. for 10 days in the presence of a nitrogen source, It is described that the polyvinyl alcohol-degrading bacteria can be bacteria belonging to the genus Pseudomonas and bacteria belonging to the genus Acinetobacter.

JP-A-8-275773 JP 2006-180706 A

In both Patent Documents 1 and 2, the time required for the decomposition of PVA is as long as 4 to 10 days, and when using this technology in activated sludge treatment with a residence time of 24 hours in the general textile dyeing industry, facilities and facilities become large, Equipment cost, volume, and area are widely required, which is not realistic.
The problem to be solved by the present invention does not require a large-scale facility, and can be achieved by operating a current facility, and provides a method for efficiently decomposing and removing a hardly decomposable substance by microorganisms at a low drug cost and operation cost. There is. In other words, microorganisms that decompose persistent substances are Pseudomonadaceae
The present invention provides a method for decomposing PVA in a short time by an activated sludge method treatment of a biological treatment method using microorganisms of Pseudomonas sp. W-4 and Chryseobacterium genus Chryseobacterium sp. W-6.

In light of the above-mentioned problems, the present inventors have conducted various studies, and as a result of the original seed development business of the Japan Science and Technology Agency, the development issue of “contained development biodecolorization treatment system for colored wastewater” from October 2005 to Heisei A search was made from an activated sludge tank that had been under development for commercialization until October 1999, and an attempt was made to separate microorganisms. This treatment system has a high COD and TOC (PVA component) removal rate, and the COD and TOC components contained in the dyed wastewater are decomposed by this equipment, so that the COD and TOC values in the treated wastewater are water pollution methods. It became possible to become less than the drainage regulation value. From this result, it is considered that bacteria (bacteria, microorganisms) that decompose the COD component and the TOC component exist in the activated sludge tank. Bacteria (bacteria, microorganisms) that decompose COD and TOC components were searched from the activated sludge tank and attempted to be separated. As a result, 12 strains were isolated. When these strains were used to sterilize the dyed wastewater from the dyeing and wastewater treatment equipment and a culture experiment was carried out using each of these strains, two strains were found that decompose and reduce the COD and TOC components.

The present invention is an activated sludge treatment of a biological treatment method, which decomposes and removes PVA, a hardly degradable substance, in a short time, thereby reducing facility costs and equipment costs, reducing running costs such as chemical costs and sludge treatment costs, A compact processing device is possible.

Hereinafter, the present invention will be described in detail.
The original seed development project of the Japan Science and Technology Agency (JST) The development issue of contract development “Biodecolorization treatment system for colored wastewater” refers to the bacteria Bacillus OY1 belonging to the genus Bacillus
-2 (Accession No .: Microtechnical Laboratories No. 13118), consisting of Bacillus bioreactor tank, activated sludge tank, raw water adjustment tank, PH adjustment tank, precipitation tank, Bacillus bacteria culture tank, etc. 1 tank is aerobic (continuous aeration), 2 and 3 are anaerobic (intermittent aeration) treatment, and the colored waste water is decolorized. The residence time is 8 hours for the bioreactor tank and 24 hours for the activated sludge tank. I do. TOC and COD were reduced by this treatment. In addition, two microorganisms Pseudomonadaceae genus Pseudomonas sp.
Chryseobacterium genus Chryseobacterium sp. W-6 is cultured, added to the activated sludge tank, and put into the sludge tank to decompose the hardly decomposable substance (PVA), thereby reducing TOC and CO in the dyed wastewater treated water. Two newly discovered bacteria grow well under aerobic conditions and degrade PVA.
The aerobic condition is usually performed by a means for supplying oxygen to the microorganism.
A flow chart of the “colored wastewater bio-decolorization treatment system” is shown in FIG.

Hereinafter, the present invention will be specifically described with reference to examples.
Example 1
Figure 2 shows the COD values for September and October 2007 in the above-mentioned “colored wastewater bio-decolorization treatment system”. The COD removal rate was 85% or more.

Pseuomonas sp. W-4 と Chryseobacterium sp. W-を組み合わせた2日後のTOC除去率は７０％以上で単独の効果より併用するほうがTOCの減少が高いことが分かった。 Example 2
Dry bouillon (Nissui Pharmaceutical) 0.5% was added to the dyeing wastewater, mixed, sterilized by autoclaving at 121 ° C for 15 minutes, and each culture solution was mixed with Pseudomonadaceae sp. Pseudomonas sp. W-4,
Chryseobacterium sp Chryseobacterium sp. W-6 of each strain 10 ⁶ cfu / ml inoculation with 36 ° C.,
After culturing for 2 days with stirring at 100 R / min, the TOC of the culture was measured.
The measurement results are shown in Table 1.

The TOC removal rate after 2 days when Pseuomonas sp. W-4 and Chryseobacterium sp. W- were combined was 70% or more, and it was found that the reduction in TOC was higher when used together than when used alone.

前項の実施例3の方法に前培養としてBacillus sp.OY1-2 で培養し、その培養液にそれぞれの菌株Pseudomonas sp. W-4 Chryseobacteriumsp. W-6 を接種して、培養した結果 Pseudomonas sp. W-4 とChryseobacterium sp. W-を組み合わせたほうがCODの減少が高いことが分かった。 Example 3
After sterilizing the original dyed wastewater with autoclave at 121 ° C for 15 minutes, put each strain on the culture solution.
10 ⁶ cfu / ml was inoculated, stirred at 36 ° C. with a stirring rate of 100 R / min, and cultured for 2 days. The culture solution COD was measured. The measurement results are shown in Table 2.

As a pre-culture in the method of Example 3 in the previous section, the cells were cultured with Bacillus sp. OY1-2, and the culture solution was inoculated with each strain Pseudomonas sp. W-4 Chryseobacterium sp. W-6. It was found that COD reduction was higher when W-4 and Chryseobacterium sp. W- were combined.

Example 4
Experiment in which 100 mg / L of PVA was added to the dyed wastewater Culture medium in which 100 mg / L of PVA (manufactured by Wako Pure Chemical Industries) was added to the dyed wastewater was sterilized and then sterilized and then added to each culture solution in the Pseudomonadaceae sp. Each strain of Chryseobacterium sp. W-6 was inoculated with 10 ⁶ cfu / ml, stirred at 36 ° C. and stirred at 100 R / min for 2 days, and then the COD of the culture was measured.
The COD measurement results are shown in Table 3.

In addition to the textile industry, PVA is widely used for industrial applications such as suspension polymerization of synthetic polymers such as adhesives, films, paper processing materials, etc., and also for household use in various applications such as laundry glue.
The discovery of bacteria that degrade PVA in a short period of time enables it to be used for wastewater treatment and sewage treatment outside of the textile industry.

Flow sheet for bio-decolorization treatment system for colored wastewater Changes in COD due to operation in bio-decolorization treatment system for colored wastewater

Claims (2)

Microorganisms that decompose persistent substances are Pseudomonadaceae sp.
A method for removing a hardly degradable substance that is W-4 and Chryseobacterium sp. The method for removing a hardly decomposable substance according to claim 2, wherein the main component of the hardly decomposable substance is polyvinyl alcohol.

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