KR100905487B1 - Biological treatment of paper mill wastewater - Google Patents

Abstract

The present invention relates to a method for treating paper wastewater using a mixed strain Nix-37 having paper wastewater treatment activity. Biological treatment of paper wastewater using the mixed strain Nix-37 of the present invention has not only high treatment efficiency but also safety and economical advantages over conventional chemical and physical treatment methods.

Paper wastewater, biological treatment

Description

Biological treatment of paper mill wastewater

The present invention relates to a method for treating paper wastewater using a mixed strain having paper wastewater treatment activity.

Pulp and paper making industry uses more water than other manufacturing industries. In the world, pulp and paper industry account for the third largest use of fresh water after the primary metal and chemical industries. Even modern efficient operating techniques use 60 m ² of water per tonne of paper [G. Thompson, J. Swain, M. Kay, and CF Forster, The treatment of pulp and paper mill effluent, Bioresource Technology, 77, 275-286 (2001). Recycling of this used water is efficient, but reuse of water that is not completely purified leads to problems for production processes and machinery [Robertson, LR, Schwingel, WR, Effect of water reuse on paper machine microbiology. In: Proceedings of the 1997 Environmental Conference, vol. TAPPI press, Norcross, GA, pp. 87-93 (1997)].

 In addition, PCBs, PAHs, and dioxin, which are contained in paper wastewater, are widely known toxic substances that can harm humans directly or indirectly [Tanu Rana, Shashank Gupta, Dhiraj Kumar, Sharad Sharma]. , Manish Rana, Vikram S. Rathore, Ben MJPereira, Toxic effects if pulp and paper-mill effluents on male reproductive organs and some systemic parameters in rats]. The treatment of paper wastewater is currently carried out in parallel with biological treatment and chemical treatment, and the conventional method is not economical in terms of cost and unsatisfactory in terms of treatment efficiency.

Accordingly, methods for recycling paper wastewater and reducing emissions have been studied in various ways. Among them, it is more economical and efficient to treat wastewater by a biological treatment method using a microbial strain having excellent substrate decomposition ability. It is necessary to isolate new microbial strains and optimize process conditions using them.

Accordingly, the present inventors have isolated the Pseudomonas species Nix-37 mixed strain having excellent wastewater treatment activity from paper wastewater and confirmed that the isolated strain can be usefully used for biological treatment of paper wastewater. .

Accordingly, one object of the present invention is to provide a method for treating paper wastewater using a mixed strain Nix-37 having paper wastewater treatment activity.

Still another object of the present invention is to provide a composition for treating paper wastewater, including mixed strain Nix-37.

In one aspect, the present invention relates to a mixed strain Nix-37 deposited with accession number KACC 91259P for treating paper wastewater and a papermaking wastewater treatment composition comprising the mixed strain Nix-37.

The "mixed strain Nix-37" used for the biological treatment of paper wastewater according to the present invention is the strains finally selected in the process of separating microorganisms having high paper wastewater treatment activity from wastewater samples of a paper mill in Gyeonggi-do. and mixed for a total of four strains, each of which is Freiburg to physiological and biochemical identification results using the API 20NE kit RIA holde (Burkholderia) 2 species, Cree consumption eggplant (Chryseomonas) 1 species and air our Nasu ( Aeromonas ) It consists of one species and has been deposited with KACC under accession number KACC 91259P.

As used herein, the term "biological treatment" refers to a process of removing organic substances including hardly decomposable substances in wastewater by multiplying microorganisms and utilizing their metabolism. The biological treatment efficiency of the papermaking wastewater of the mixed strain Nix-37 of the present invention was determined by measuring COD _Mn in the influent and the effluent to the extent that the organic material was removed, and it was confirmed that the organic material removal efficiency was greater than 90%.

In particular, the mixed strain of the present invention has the advantage that each of the strains in the mixed strain complementary to the various wastewater environment exhibits a synergistic treatment effect appropriately according to the environmental conditions.

The composition of the present invention comprises (i) mixed strain Nix-37 alone; Or (ii) in addition to the mixed strain Nix-37, other microorganisms having papermaking wastewater treatment activity may be further mixed.

In addition, the composition of the present invention may further add a variety of additives such as preparations to increase the preservation, agents to promote reactivation, excipients, etc., in addition to the microorganism, it can be prepared in a variety of formulations, such as liquid or powder.

As another aspect, the present invention relates to a papermaking wastewater treatment method using a mixed strain Nix-37.

The wastewater treatment method using the mixed strain Nix-37 of the present invention is not particularly limited and may be used in all methods known to those skilled in the art. Activated sludge treatment process, upflow anaerobic sludge blanket (USAB), advanced oxygen process (AOP), biological aerated filter (BAF), trickling filter process Specific examples include biological treatment methods such as oxidation pond and rotating biological contactor, and activated sludge method is preferable.

When the mixed strain Nix-37 of the present invention is applied to the activated sludge method, the administration method, administration time, administration conditions, etc. of the strain can be appropriately selected by those skilled in the art. For example, the mixed strain Nix-37 of the present invention may be treated by a suspension method in which the mixed strain Nix-37 is suspended in the wastewater, or treated in a fixed form in which the strain is fixed to a support.

When the mixed strain of the present invention is applied to the activated sludge method, the mixed strain Nix-37 exhibits high activity so that 2 to 3 mg / L of DO (Dissolved Oxygen) and 3,000 to 4,000 mg / L of MLSS (Mixed Liquor Suspended Solid) ), 24 to 48 hours of HRT (Hydraulic Retention Time), 20 to 30 days of SRT (Solids Retention Time).

Specifically, the mixed strain Nix-37 of the present invention maintains DO of the first and second aeration tanks at 2 mg / L and 3 mg / L in the bioreactor having the schematic diagram as shown in FIG. 48 hours, when maintained for 30 SRT days showed the highest 93.1% _Mn COD removal efficiency, COD _Mn of this time, the effluent exhibited the lowest 33.5 mg / L.

COD _Mn of the effluent The value is much lower than 40 mg / L of COD _Mn , the effluent water quality standard, and when papermaking wastewater is treated with the mixed strain Nix-37 of the present invention, the final treatment is performed with effluent that satisfies the COD _Mn value suitable for the effluent standard. It means you can do it.

By biologically treating the paper wastewater using the mixed strain Nix-37 according to the present invention, it can be performed more safely and economically without the generation of toxic secondary pollutants than conventional chemical and physical treatment methods.

Hereinafter, the present invention will be described in more detail with reference to Examples.

The following examples are merely illustrative of the present invention, but the content of the present invention is not limited by the examples.

Example  One

(1) Experiment and Reactor Operation

The paper wastewater used in the present invention was obtained from the flotation tank of a paper mill in Gyeonggi-do. In the present invention, since the properties of the wastewater discharged vary according to the type of paper produced, in the present invention, samples were taken according to the type of paper and used as influent in the reactor in consideration of advantages. The laboratory scale reactor was made of acrylic material and consisted of influent tank, first aeration tank, second aeration tank, and sedimentation tank. The volumes of the first and second aeration tanks were made of 15L and 20L, respectively (Fig. 1).

The temperature of the aeration tank was maintained at 23 to 25 ° C. The inflow water tank and the settling tank were installed in the mixing device so that the mixing was possible in a cylindrical shape, and the inflow water quality was equal, and in the aeration tank, the agitation device that could be designated from 0 to 200rpm was installed to facilitate the mixing of the sludge. In the circular sedimentation tank, a 1-rpm stirrer was installed to induce sludge settling and smooth sludge collection. The influent wastewater was moved to the first aeration tank and the second aeration tank by a pump, and the return sludge from the sedimentation tank to the first aeration tank was adjusted to 1Q relative to the influent flow rate.

(2) Analysis method

Organic matter concentration was measured by COD _Mn , and DO was measured by YSI model 58 at 2 hour intervals. The pH was measured every day using PHM 92 by Radiometer, using the sample obtained for organic matter measurement. MLSS and MLVSS measurements were performed daily according to standard methods (preferably documenting exemplary literature).

(3) Isolation of Highly Efficient Strains

The mixed strain Nix-37, which has excellent ability of removing organic substances, was isolated from paper wastewater.

(3-1) Proliferation Culture and Strain Separation

100 ml nutrient broth (Difco, U.S.A.) was put into a 500 ml bottle and wet sterilized at a temperature of 121 ° C. for 15 minutes, and 10 ml of the papermaking wastewater was added and cultured for 48 hours. After culturing the cultured culture medium using a streak plate method to isolate the strain into a single strain, it was confirmed whether the pure separation through gram staining.

(3-2) Screening Test

Screening tests were conducted to determine the organic matter removal ability of each purely isolated microorganism. At this time, the experiment was performed using the stock solution of paper wastewater for the growth of microorganisms. The inoculation concentration of the microorganisms was 1.0 g / L (wet weight) and the amount of wastewater was 100 ml. COD _Mn was measured twice at 0h and 48h to confirm the organic removal ability.

0h 48h Rem. (%) 0h 48h Rem. (%) Blank 567.8 556.4 2.0 D13 567.8 241.3 57.5 D4 567.8 395.1 30.4 D15 567.8 247.0 56.5 D14 567.8 428.6 24.5 D2 567.8 254.7 55.1 D19 567.8 429.5 24.4 D20 567.8 272.8 52.0 D5 567.8 447.2 21.2 D6 567.8 314.7 44.6 D8 567.8 475.7 16.2 D11 567.8 344.8 39.3 D1 567.8 485.2 14.5 D9 567.8 348.4 38.6 D10 567.8 495.7 12.7 D16 567.8 355.5 37.4 D7 567.8 521.9 8.1 D17 567.8 356.9 37.1 D3 567.8 528.4 6.9 D12 567.8 365.9 35.6 D18 567.8 547.7 3.5

A total of 24 microorganisms were isolated from the papermaking wastewater, and each of them was screened and four highly efficient strains were selected. D13, D15, D02, and D20 were identified as API Kit 20NE by physiological and biochemical identification. D02 has been identified as a Cryeomonas species and D15 has been identified as an Aeromonas species. Mixed strain Nix-37 prepared by mixing these four microorganisms was used in the reactor study.

D13 D15 D2 D20 Shape rod rod rod rod Gram - - - - Size 0.5-0.7x1.0-1.5 0.5-0.7x1.0-1.5 0.5x1.0-1.5 0.5x1.0-1.5 Catalase + + + + Oxidase - - - - NO3 + + + + IND - - + + ADH + - + - URE - - - - ESC - - + + GEL - - + - PNPG + + + + GLU + + - + ARA + + - + MNE + + - + MAN + + - + NAG + + - + MAL + + - + GNT + + - + CAP + + - - ADI - - - - MLT + + - + CIT + + - - PAC + + - + Burkholderia sp. Burkholderia sp. Chryseomonas sp. Aeromonas sp.

Abbreviation: NO 3, nitrate reduction; IND, indole production; ADH, arginine dihydrolase; URE, urease; ESC, hydrolysis esculin; GEL, hydrolysis gelatin; PNPG, β-galactosidase; GLU, D-glucose; ARA, L-arabinose; MNE, D-mannose; MAN, D-mannitol; NAG, N-acetyl-glucosamine; MAL, D-maltose; GNT, potassium gluconate; CAP, capric acid; ADI, adipic acid; MLT, malic acid; CIT, trisodium citrate; PAC, phenylacetic acid

As of August 1, 2006, the mixed strain Nix-37 having high treatment efficiency with respect to the paper wastewater isolated in the present invention was obtained from the Korea Agricultural Culture Collection (KACC) located at 225, Seodun-dong, Gwon-gu, Suwon-si, Gyeonggi-do. Deposited under accession number KACC 91259P.

For culturing the strain, nutrient broth (Difco) was used as a medium. Mixed strains cultured for 24 to 48 hours were injected into the first aeration tank at intervals of 7 to 10 days at 5 g / L (w / w).

(4) reactor conditions

Dissolved Oxygen (DO), Mixed Liquor Suspended Solids (MLSS), Hydraulic Retention Time (HRT), and Solids Retention Time: SRT) The efficiency of paper wastewater treatment in the reactor was observed through various changes of four factors.

The change in DO gave 0.5 mg / L and 2 mg / L of DO in the first aeration vessel, and the other conditions were maintained for MLSS 4000, HRT 24 hours, and SRT 20 days.

In the case of the change of MLSS, treatment efficiency was confirmed by MLSS 3000 and MLSS 4000, and other conditions were maintained at HRT 24 hours, SRT 20 days, and DO at 2 mg / L and 3 mg / L, respectively. .

HRT was conducted in 24 hours and 48 hours, and the other conditions were adjusted to 20 mg of SRT, MLSS 4000, and DO to 2 mg / L and 3 mg / L, respectively. The temperature of all conditions was maintained at 23 to 25 ° C.

(5) Influent Properties

The chemical oxygen demand (COD _Mn ) of the influent varied according to the type of paper produced. The representative influent species and COD _Mn are shown in Table 3.

Characteristics of influent by region (Unit: mg / L)  Kind COD _Mn Species COD _Mn Species COD _Mn Species COD _Mn C300, SKP 524.0 CB, KAY 507.6 CB, D 596.7 K2 457.4 K2, CA 650.0 C, CB 887.7 CB400, D 612.7 CA, D 628.9 CA, KAR 495.0 CB, KAR 633.4 YK 727.3 SKP, D 678.5 CB, SKP 619.0 CB, KAY 636.1 KAY, D 721.1 CA, KAY 600.0 CA.D250 553.0 CA, D 631.8 CA, D 715.8 SKP, CB 444.6

Example  2

(1) Treatment efficiency according to DO change

As a result of analysis of treatment efficiency according to the change of DO in the first aeration vessel while maintaining MLSS 4000 mg / L, HRT24h, and SRT for 20 days, the concentration of organic matter in the influent was 326.6 to 625.8 mg as a result of maintaining DO at 0.5 mg / L. The average of 468.0 mg / LCOD _Mn / L, the treatment efficiency was 72.5-85.9%, 79.9% of the average (Fig. 1a). In addition, as a result of maintaining DO of the first aeration tank at 2 mg / L, the organic matter concentration of the influent was 348.5 to 772.2 mg / L, the average concentration was 535.2 mg / L, and the treatment efficiency was 80.7 to 91.5%. 85.3%. Figure 1b).

2) Treatment efficiency according to MLSS change

For HSS 24h, SRT 20 days, DO was maintained at 2 mg / L of the first aeration basin and 3 mg / L of the second aeration basin, for the MLSS 3000, the influent concentration COD _Mn ) was 418.0 to 663.3 mg / L, averaging 534.4 mg / L. The result of analysis of the treatment efficiency was 73.4% on average, and the lowest was 64.0% and the highest was 89.6%. In this case, the treatment efficiency is unstable depending on the concentration of the influent water. On the other hand, for the MLSS 4000, the concentration of influent was 316.4 to 820.6 mg / L with an average concentration of 554.7 mg / L. The treatment efficiency was 77.5 to 91.7%, and the average treatment efficiency was 83.1%. MLSS 4000 is more stable and shows better efficiency than MLSS 3000 (FIG. 2B).

3) Treatment efficiency according to HRT change

SRT 20 days, MLSS 4000mg / L, DO is maintained at 1mg of 1st basin and 2mg of 2nd basin, 3mg / L of 2nd basin, influent concentration of 316.4 to 820.6mg / L when the treatment efficiency for organic matter is 24 hours of HRT _Mn , the average was 554.7 mg / L CODmn, the treatment efficiency was 77.5 to 91.7% and the average treatment efficiency was 83.1% Figure 3a.). For 36 h of HRT, the influent concentrations ranged from 412.8 to 635.9 mg / L COD _Mn , with an average of 507.9 mg / L. Treatment efficiency ranged from 81.4 to 91.5% with an average rate of 86.5%.

For 48 hours of HRT, the influent concentrations ranged from 368.1 to 655.9 mg / L COD _Mn with an average of 498.4 mg / L. The treatment efficiency ranged from 88.2 to 93.4% with an average removal efficiency of 90.3%. HRT 48 hrs showed a stable 90.3% TCOD _Mn removal rate regardless of the concentration. Changes to 48 hours of HRT showed a more stable removal rate (FIG. 3C).

4) Processing efficiency due to SRT change

Maintain MLSS 4000mg / L, HRT 48 hours, DO 1st aeration tank 2mg / L, 2nd aeration tank 3mg / L, and SRT 20, the influent concentration is 368.1 to 655.9 mg / L as shown in Fig. 4a. The mean COD _Mn was 498.4 mg / L. The treatment efficiency was 88.2 to 93.4%, and the average removal efficiency was 90.3%. For 30 days of SRT, the concentration of influent was 401.6 to 539.7 mg / L COD _Mn , and the average influent was 444.3 mg / L. Treatment efficiency ranged from 90.1 to 93.1%, representing an average removal efficiency of 91.7%. Both SRT 20 and 30 showed good efficiency, but SRT 30 showed a little more stable and high removal rate (FIG. 4B).

5) Optimum condition

As shown in Fig. 4, the optimum conditions for paper wastewater treatment are HRT for 48 hours, MLSS for 4000, SRT for 30 days, and DO for 2nd and 2nd aeration tanks, respectively, 2 mg / L and 3 mg / L. The maximum removal efficiency was 93.1% and the lowest value of effluent was 33.5 mg / L CODmn.

1 shows a schematic of a bioreactor for biological treatment of papermaking wastewater.

2 shows the TCOD _Mn between the influent and the effluent in (a) 0.5 mg / L of DO in the first aeration tank and (b) in a condition of DO of 2 mg / L in the first aeration tank (◆: influent, ■: Runoff, ▲: removal efficiency), arrow means seed input.

Figure 3 shows the results of the TCOD _Mn between the influent and the effluent under (a) HRT 24 hours, (b) HRT 36 hours, (c) HRT 48 hours and (◆: influent, ■: effluent, ▲: removal Efficiency), arrow means seed input.

4 is a result of examining the TCODmn (◆: influent, ■: effluent, ▲: removal efficiency) between the influent and the effluent when the SRT is maintained for 30 days, and the arrow indicates the seed agent input.

Claims (4)

The Burkholderia deposited as accession No. 91259P KACC for processing paper wastewater Liao (Burkholderia) 2 species, Cree consumption eggplant (Chryseomonas) 1 species and Pseudomonas aero (Aeromonas) Mixed strain Nix-37 consisting of one species. Activated sludge treatment process, upflow anaerobic sludge blanket (USAB), advanced oxygen process (AOP), biological aerated filter (BAF), trickling filter process In the process of treating paper wastewater using biological treatment methods such as oxidation pond, rotating biological contactor, The biological treatment method is deposited as accession No. 91259P KACC Burkholderia (Burkholderia) 2 species, Cree consumption eggplant (Chryseomonas) 1 species and Pseudomonas aero (Aeromonas) The papermaking wastewater treatment method characterized by using the mixed strain Nix-37 which consists of 1 type. The method according to claim 2, wherein the activated sludge method is used. According to claim 3, DO Dissolved Oxygen) 2 to 3 mg / L, MLSS Mixed Liquor Suspended Solid) 3,000 to 4,000 mg / L, HRT Hydraulic Retention Time (24 to 48 hours), SRT Solids Retention Time (20) Retaining for 30 to 30 days.

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