KR100348740B1 - A media for treating waste water entrapped with microorganism using cellulose acetate - Google Patents

Abstract

The present invention relates to a carrier in which microorganisms used for biological treatment of wastewater are biologically immobilized, and a method for preparing the same. In a microorganism fixed carrier in which microorganisms are fixed to cellulose acetate, acetic acid having a degree of acetic acid of 60% or more Cellulose; And heterotrophs selected from the group consisting of Pseudomonas, Pseudomonas, Bacillus and Thiobacter, Autotrophs and Fungi. It is characterized by solidification of mixed microorganisms for wastewater decomposition, excellent strength characteristics, and excellent biological treatment efficiency of environmental pollutants.

Description

A microorganism fixation carrier for wastewater treatment, and a method for producing the same, fixed with microorganisms using cellulose acetate {A MEDIA FOR TREATING WASTE WATER ENTRAPPED WITH MICROORGANISM USING CELLULOSE ACETATE}

The present invention relates to a carrier in which microorganisms used for biological treatment of wastewater are biologically fixed, and more particularly, to a microorganism used for biological treatment of wastewater using cellulose acetate. The present invention relates to a carrier and a method for preparing the same.

Wastewater treatment technology using microorganisms can be roughly classified into a floating growth reactor and a microbial fixation reactor according to the growth patterns of microorganisms maintained in the reactor.

Suspended growth type system is a system that keeps the microorganisms in the reaction tank freely mixed with the wastewater to be treated, and activated sludge system is the typical process, and it is also the most widely used method for the existing wastewater treatment process. However, this method has the disadvantage of high energy requirements and difficult operation.

To this end, one of the alternative methods is a biofilm method is widely used as wastewater treatment using a microorganism immobilization method. The biofilm process is a method of attaching and treating microorganisms to a suitable carrier to solve the solid-liquid separation problem that is most problematic in activated sludge process, and long solids regardless of hydraulic retention time (HRT). The solid retention time (SRT) can be maintained, which has been widely used in various types of wastewater treatment.

However, the biofilm has a disadvantage in that it takes a long time to form the biofilm by a method using a natural phenomenon in which microorganisms adhere to and grow on the surface of the carrier.

In addition, like the floating growth reactor, the type of microorganisms retained in the reactor cannot be artificially selected and the thickness of the biofilm cannot be controlled. Therefore, stable operation is very difficult, such as biofilms dropping out or very thin biofilms are formed depending on process instability or the type of substrate to be treated.

If such a biofilm process is called a passive immobilization method, a new type of treatment method that captures and treats a desired amount of microorganisms in a gel matrix in a desired amount is called microbial active capture technology.

Microbial active capture technology is a new concept in wastewater treatment, a process that has been used in pharmaceutical manufacturing and other bioconversion processes.

In this bioconversion process, specific microorganisms are captured and used in a gel matrix to obtain a desired substance. The gel matrix used here is a natural gel such as agar, k-carrageenan, and alginate (natural gel).

Since the natural gel is a natural substance, it can be captured without inhibiting the activity of the microorganisms captured in the capture process, but the mechanical strength is weak, and thus it cannot be used in wastewater treatment reactors.

In addition, microorganism capture technology has been developed using phosphorus-combinable gel materials such as polyvinyl alcohol (PVA) and polyethylene glycol (PEG), but they can be used for wastewater treatment, taking advantage of the forced capture method as well as natural gels. In order to achieve the most important problem, the intensive mixing and the aeration, etc. have a problem in that they have a limited lifetime and have limited application in the field because they do not have sufficient mechanical strength to withstand the reaction conditions.

In order to solve the above problems, the strength characteristics are improved by using cellulose acetate, which is one of artificial synthetic gels having a stable strength, as a carrier used for biological treatment of wastewater. A new form of material available for the removal of various environmental pollutants Comprehensive An immobilization method and a carrier to which microorganisms are fixed are provided.

1 is a view showing the BOD removal performance with respect to the operating time of the carrier-immobilized microorganism prepared according to the present invention.

Figure 2 is a cross-sectional SEM photograph taken by cutting the central portion of the carrier for treating wastewater, which has immobilized the microorganism prepared according to the present invention.

Figure 3 is a cross-sectional SEM photograph taken by cutting another part of the carrier for treating wastewater, which immobilized the microorganism prepared according to the present invention.

The present invention to achieve the object as described above,

A microorganism fixed carrier having microorganisms immobilized on a cellulose acetate carrier, comprising: cellulose acetate having an acetic acid degree of 60% or more; And heterotrophs selected from the group consisting of Pseudomonas, Pseudomonas, Bacillus and Thiobacter, Autotrophs and Fungi. The present invention provides a microorganism encapsulating and immobilizing carrier for treating wastewater, characterized in that the microorganisms for wastewater decomposition are mixed and solidified.

In addition, the present invention comprises the steps of dissolving cellulose acetate in dimethylene chloride to form a solution;

Mixing the concentrated or centrifuged active microorganisms into the solution;

It provides a method for producing a microorganism encapsulating immobilization carrier for treating wastewater, characterized in that it comprises the step of putting the mixed solution into the mold and then solidified by pouring toluene for 12 to 24 hours.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail.

The present invention utilizes cellulose acetate, which is one of artificial synthetic gels having stable strength, for the removal of various environmental pollutants by forcing microbial capture.

Cellulose acetate uses cellulose acetate with 60% acetate. 80 to 100 kg of such cellulose acetate is dissolved in 1 m ³ of dimethylrenololide to prepare a cellulose acetate solution. If the amount of cellulose acetate is outside the above range, solubility and strength of the prepared carrier are poor, which is not preferable.

50 to 400 kg of the concentrated or centrifuged active microorganisms are mixed in the prepared solution. The higher the amount of microorganisms to be mixed is preferable, but the higher the amount of microorganisms, the lower the strength of the produced solid carrier is not preferable, and the lower the amount of microorganisms, the lower the wastewater treatment rate is not preferable.

Examples of the microorganism include microorganisms selected from the group consisting of various heterotrophs, autotrophs, and fungi, such as nitride bacteria, Pseudomonas, Bacillus, and Thiobacter. Preference is given to using.

The mixture is placed in a mold of a constant size and then poured with toluene and left to solidify for 12 to 24 hours. The toluene is used as a hardening agent to harden the carrier mixed with microorganism and cellulose acetate, and the settling time is the time required for the reaction. The reaction time is short, the hardening occurs less the strength and the reaction time is too long. The activity of is severely inhibited, so it is time to settle only the minimum time that curing can occur.

The frame may be of any shape, such as square, round, spherical, etc. required.

If the solidified gel (gel) is taken out of toluene and immersed in water to wash the chemical while stirring, a carrier for treating wastewater and wastewater in which the microorganism according to the present invention is immobilized is obtained.

In addition, a low strength phosphorus gel material such as polyvinyl alcohol (PVA) and polyethylene glycol (PEG) may be prepared and coated on the surface to increase the strength of the carrier to which the microorganism is fixed.

As can be seen from the scanning electron microscope (Scanning Electron Microscope (SEM)) pictures shown in Figures 2 and 3 attached to the microorganisms prepared as described above, it can be seen that the microorganisms are uniformly and uniformly immobilized throughout the prepared carriers. have.

In addition, the prepared microbial carrier has a maximum compressive strength of 10 kg or more than the compressive strength of 0.10 to 4.92 kg / cm 3 when PEG is used at 30 kg / cm 3 or more.

In addition, the strength of the strong acid and strong alkaline water does not change significantly, so it can be applied to water treatment in various fields.

Hereinafter, preferred examples are provided to aid in understanding the present invention. However, the following examples are only presented to aid the understanding of the present invention, and the present invention is not limited to the following examples.

Example 1

100 g of cellulose acetate (61% acetic acid) was dissolved in 1 m ³ of dimethylene chloride, 250 g of centrifuged sewage treatment plant return sludge was added thereto to prepare a mixed solution, and the mixed solution was placed in a rectangular frame. Toluene was poured and allowed to stand for 12 to 24 hours to solidify. The solidified gel was taken out of toluene, immersed in water, and washed with chemicals with toluene while stirring to obtain about 1.1 to 1.4 L of product.

The microorganisms prepared as described above were measured and the properties of the carriers are shown in Table 1 below.

TABLE 1

The said result is an average value obtained by experimenting 5 times repeatedly.

As shown in Table 1, the carrier according to the present invention has a density of 1.076 g / cm 3 and can be flowed in water with a porosity of 42.76%. In addition, the compressive strength was 30.79 kg / cm 3, which is difficult to measure the compressive strength with other phosphorus gels, and is also reported to be very low, such as Japan's Tatsuo Sumino et al. (Journal of Fermentation) and Bioengineering, vol. 73 (1), pp. 37-42, 1992), have strengths significantly greater than the maximum compressive strength of 0.10 to 4.92 kg / cm 3 of gels prepared using polyethylene glycol (PEG). It was found to be excellent.

In addition, it was found that the changes in compressive strength and tensile strength were not large in resistance to acids, alkalis and heat.

On the other hand, one of the important problems of the carrier properties in addition to the strength of the gel matrix is whether the entrapped microorganisms lose most of the activity during the capture process, Figure 1 (●: BOD of influent water, ○: BOD of effluent water is 40% filling rate of comprehensive microbial fixation carrier, microorganism concentration (MLSS) is 14,425 mg / l, and it shows the activity of HRT for 8 hours when microorganism is treated with household wastewater. As shown in FIG. 1, the microbial carrier of the present invention has very good activity in the sewage purification experiment, and as shown in FIG. 2, the central part of the carrier of the present invention is cleaved after 96 days of the experiment. In the scanning electron micrograph taken by the high density microorganisms are present, and as can be seen in Figure 3, the other part of the microorganism carrier of the present invention is cut In scanning electron micrographs showed that the presence of microbial density.

Accordingly, the carriers in which the microorganisms of the present invention are immobilized are consistent with the existing reports that the carriers recover their activity after a period of time despite the concern of reducing activity due to the chemicals used during the manufacturing process.

The carrier to which the microorganism prepared by the present invention is immobilized can provide a carrier for treating sewage and wastewater, in which the microorganism is immobilized with excellent strength characteristics and excellent microbial treatment efficiency.

Claims (7)

A microorganism fixed carrier having microorganisms immobilized on a cellulose acetate carrier, comprising: cellulose acetate having an acetic acid degree of 60% or more; And heterotrophs selected from the group consisting of Pseudomonas, Pseudomonas, Bacillus and Thiobacter, Autotrophs and Fungi. , Wastewater treatment carrier characterized in that the solidified by mixing the microorganisms for wastewater decomposition. delete delete The method of claim 1, A carrier for wastewater treatment, wherein the carrier is coated on the surface with polyvinyl alcohol or polyethylene glycol. Dissolving cellulose acetate in dimethylene chloride to form a solution; Mixing the concentrated or centrifuged active microorganisms into the solution; And The method for producing a wastewater treatment carrier, comprising the step of placing the mixed solution in a mold and then pouring it with toluene for 12 to 24 hours to solidify it. The method of claim 5, The amount of the cellulose acetate used is 80 to 100 kg based on 1 m 3 of dimethylene chloride, a method for producing a wastewater treatment carrier. The method of claim 5, The microorganism is selected from the group consisting of heterotrophs, autotrophs and fungi selected from the group consisting of nitride bacteria, Pseudomonas, Bacillus, and Thiobacter. Oh, the method for producing a waste water treatment carrier.