JP2992931B2 - Cleaning plant wastewater treatment system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for treating organic contaminants in wastewater from a cleaning plant, clarifying the treated water, and then releasing the discharged water or returning to the washing process of the plant so that it can be reused as washing water, rinsing water and the like. Cleaning system wastewater treatment system.

[0002]

2. Description of the Related Art Conventionally, the main equipment for wastewater treatment in a cleaning factory has been subjected to wastewater treatment by either an activated sludge method or a coagulation sedimentation method and then discharged or used as reused water. In either case, it is difficult to secure the quality of treated water due to fluctuations in the raw water quality due to fluctuations in the quality of the clothing material of the user, fluctuations in the washing process of the factory, etc. In addition, the installation area is large, and the capacity as reuse equipment Is low, and is currently operating as an environmental protection facility as a wastewater treatment facility.

[0003] The cleaning industry, particularly the linen supply industry, is an industrial field where the cost of water is the largest relative to the production cost, and is therefore an important factor that directly affects business management. It is difficult to secure the quality of treated water, and it is not profitable as reused water.

As described above, in the cleaning industry, the cost of water is strictly required relative to the production cost, and this is an important factor directly affecting the management. At the same time, many factories are located near urban areas because of the distribution characteristics of users. Due to regulations, additional pretreatment costs due to groundwater pollution, increased unit prices for water and sewage, industrial water, and increased wastewater treatment costs due to stricter wastewater regulations, cleaning plant wastewater treatment facilities are becoming more compact, lower in cost, and operating and managing. Ease is essential.

[0005] 1. Conventional method-1 By the way, the processing system by the conventional activated sludge method is mainly processed by the flow of the following figure.

The factory wastewater whose flow rate has been adjusted by the adjusting tank is treated by an activated sludge method, and is separated into solid and liquid in a sedimentation tank.
A part of the treated separated liquid is discharged to the sewer or purified by sand filtration to remove trace COD (chemical oxygen demand) and chromaticity to purify water quality to reuse water quality. Remove with tower and activated carbon tower. Further, a method of performing ozone treatment to remove odor, chromaticity, and the like has been generally used.

In the conventional activated sludge method, it is necessary to maintain and control the activated sludge in the aeration tank due to fluctuations in factory wastewater, and in particular, a large amount of control is required to prevent the occurrence of filamentous fungi due to bulking.

Since the water quality of the above-mentioned sedimentation tank is determined by the maintenance and management of solid-liquid separation, it is necessary to maintain and manage the prevention of water quality deterioration due to floating of scum in summer and precipitation in winter.

Further, in order to obtain the above-mentioned recycled water,
Furthermore, sand filtration, activated carbon, and ozone treatment are performed. These require operation and maintenance depending on the water quality of the sedimentation tank.

[0010] 2. Conventional method-2 Further, a general wastewater treatment apparatus in which a separation membrane is installed in an aeration tank and is treated by an activated sludge method follows the following flow.

The activated sludge aeration tank provided with the above separation membrane can purify organic sludge substances by operating MLSS (suspended matter) at a higher concentration MLSS than the conventional activated sludge method. Speed is 0.6-0.8kg BOD
/ M ³ · day, which makes it impossible to secure stable treated water, and there is a problem as an advanced treatment device for obtaining reprocessed water. Instead, it was a low device in practical terms.

[0012]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned technical problems of the conventional methods 1 and 2 at a glance, and makes it possible to carry out a treatment that facilitates operation management and maintenance. The goal is to get a processing system.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above viewpoints, and comprises a regulating tank, a humus pellet, a microorganism carrier such as a nonwoven fabric, and a cylindrical or flat plate. The purpose of the present invention is to provide a cleaning plant wastewater treatment system comprising a membrane aeration tank equipped with a separation membrane structure molded into a shape and an aeration device for supplying aerated air, an activated carbon tower and peripheral equipment. is there.

[0014]

The structure of one embodiment of the present invention will be described below with reference to the drawings. First, if the system is shown by a flow, it will be as shown in the figure below.

By installing a microorganism carrier such as a nonwoven fabric, a corrosive human pellet and a separation membrane as a microorganism treatment apparatus in the above-mentioned membrane aeration apparatus, highly concentrated organic pollutants in the wastewater from a cleaning plant can be highly purified. Efficient BOD (Biological Oxygen Demand), COD treatment and flocculation of SS (suspended matter) by purifying with high efficiency to enhance the solid-liquid separation effect of the separation membrane surface, and to achieve stable advanced treated water quality Provides a water amount, generates almost no odor, and performs stable treatment as treated water.

Further, in order to obtain efficient solid-liquid separation and a high amount of permeated water, the surface of the separation membrane is washed as necessary. As a result, the solid-liquid separation ability of the separation membrane surface can be restored, and a stable high quality treated water quality and water amount can be provided.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the flow of the cleaning factory wastewater treatment system. The factory wastewater 1 to be treated by the present system is managed by the regulating tank 2 to supply a constant amount to the membrane aeration tank 3 and stabilize the water quality.
The factory wastewater 1 containing organic pollutants supplied to the membrane aeration tank 3 by the above method is a continuous aeration in the membrane aeration tank 3, and is a human pellet (humus substance) placed in a section partitioned by the partition plate 5.
It is treated by 6 soil fungus groups.

MLSS (suspension material) in the membrane aeration tank 3
Is operated with high concentration of humus sludge of soil bacteria group induced by 6,000 to 12,000 mg / l of humus pellets 6, and has a high effect of removing BOD and COD and generates a small amount of sludge. Due to the soil fungi induced by the humus pellets, the BOD volume load is:
Decompose and purify organic pollutants with a high load of 0.5 to 1.5 kg · BOD / m ³ · day. The organic pollutants decomposed and purified in the membrane aeration tank 3 become sludge, and are subjected to solid-liquid separation by a suction pump 7 by a separation membrane 8 installed in the membrane aeration tank 3.

The suction pump 7 sucks the treated water in a continuous or intermittent operation and supplies it to the activated carbon tower 9 at the subsequent stage to adsorb and remove trace COD components such as pigments, odors and detergents in the treated water. The obtained treated water is supplied to a treated water tank 11 by a treated water pump 10, and a necessary amount of water is extracted by a pump in a washing step or the like, and can be used as reuse water.

The washing of the separation membrane 8 in the membrane aeration tank 3 is performed by removing air and organic substances adhering to the surface of the separation membrane. It is cleaned by the flow and the suction / cleaning operation by the pump. In order to improve the cleaning effect,
Chemical cleaning of the separation membrane 8 is also performed periodically. Sludge is stored in a sludge tank of ancillary facilities, extracted as industrial waste, and disposed of.

1. Treatment Effect 1 By placing the humus pellets 6 in the membrane aeration tank 3, the effect of humus sludge utilizing the metabolic function of microorganisms in the soil has COD treatment characteristics as compared with the activated sludge method. As shown in FIG. 3, the removal rate is high and the removal rate is high. MLSS (suspension material) has a low increase in MLSS concentration despite the high decomposition rate of organic sludge material.

As described above, the provision of the humus pellets 6 in the membrane aeration tank 3 has a high effect on high-efficiency treatment of BOD and COD, reduction of volume of excess sludge, and fluctuation of load. Such an effect is due to the inorganic substances (SiO ₂ , Al, Fe, etc.) eluted into the membrane aeration tank 3 by the humus sludge induced by installing the humus pellets 6 and the humic substances (humin, fulvic acid, humic acid) )).

In addition, compared with the activated sludge, the treatment characteristics of the COD treatment effect shown in FIG. 3 and the MLSS change over time in FIG. 4 show a high effect on the sludge volume reduction. As compared with the conventional method, the effect is high as shown in Table 1 below.

[0024]

2. Treatment Effect 2 On the other hand, the microbial carrier (nonwoven fabric) 13 is easy to adhere to sludge, has a high cell retention amount, and has a MLSS of 6,000 to 1
Holds 2,000mg / l, no worry of clogging,
Decomposes most of organic pollutants. By filling the nonwoven fabric, it is possible to maintain the organic matter-treated bacteria at a high density. Table 2 below shows a comparison with the conventional method.

[0026]

3. Treatment effect 3 Humus pellet 6, filling non-woven fabric of microbial carrier 13,
The present system based on the synergistic effect of the separation membrane 8 has a high effect as shown in Table 3 below as compared with the conventional method.

[0028]

Next, an example of the water quality value obtained by the present invention will be described. The high-concentration organic pollutants treated in the membrane aeration tank 3 as described above become sludge, and are separated into solid and liquid by the separation membrane 8. Further, in order to obtain an effective solid-liquid separation and a high permeated water amount, chemical cleaning of the separation membrane 8 is performed as necessary. The treated water obtained by the separation membrane 8 is sent to the activated carbon tower 9 by the suction pump 7, and a small amount of CO such as pigment, odor, detergent, etc.
The highly treated water which removed the D component by adsorption and could be reused in the cleaning step was obtained. Table 4 below shows an example of the water quality value of the highly treated water.

[0030]

Hereinafter, an example of the processing flow of the present invention and the structure of the membrane aeration tank will be described. 1. The processing flow of the present invention is as follows.

2. Regarding the membrane aeration tank of the present invention Conventionally, a membrane is installed in an activated sludge tank to separate SS (floating substances), but the present invention uses a humus pellet 6, a microbial carrier (filled with nonwoven fabric) 13 and a separation membrane 8 When installed, the organic matter is efficiently decomposed, the amount of generated SS is reduced, and the SS is separated by a membrane. FIG. 2 shows an outline of the configuration of an example of the membrane aeration tank 3 constituting the system of the present invention.

Hereinafter, the installation method and structure of the above-mentioned humus pellet (humus) and its components will be described. 1. About the installation method and structure of the humus pellets The following two cases are used depending on the processing equipment. Installed in culture tank Installed in aeration tank

The installation method is 5 to 10 mm in diameter and 10 in length.
A cylindrical pellet of about 20 mm is filled in a metal or resin mesh bag and immersed in an aeration tank, and fixed at a position where replenishment in the tank is possible. The amount of the humus pellets to be charged is 0.5 to 1.5 kg per 1 m ^{3 of} sludge as a standard. The pellet repeatedly comes into contact with the sludge and gradually elutes. The replenishment of the pellets will be replaced approximately once a year after the start of operation of the apparatus.

2. About the components of the Humas pellets The analysis results of the main components of the Humas pellets are shown in Table 5 below. The organic content of the humus pellets is 35% to 45%, and 55% to 65% is inorganic.

[0036]

Next, the above-mentioned microorganism carrier (nonwoven fabric)
The installation method, the structure, the material and the effect thereof will be described. 1. About the installation method, structure and material of the microbial carrier The microbial carrier is a fixed-bed type microbial carrier with a structure that enables the microorganisms that treat organic pollutants to adhere, capture and grow reliably, and that can retain high-concentration microorganisms. is there. The material is non-woven fabric such as polypropylene fiber, and the shape is cylindrical, mesh,
The one molded into a flat plate or the like is used. The installation method is such that a fixed bed such as a net box soaked in a membrane aeration tank is provided, and the microorganism carrier is randomly filled therein. In such a case, the filling method is such that aeration air and aeration liquid flow easily pass, the absorption rate of oxygen contained in the aeration air is high, and the electric energy (aeration pump) required for aeration is reduced.

2. Effect of microorganism carrier The concentration of microorganisms in the membrane aeration tank is 6,000 to 12,000 m.
g / l (MLSS), the BOD load per membrane aeration tank capacity can be increased, and the membrane aeration tank can be made compact. Further, since the high-concentration MLSS can be maintained, it is possible to cope with a shock load against a load fluctuation of the raw water quality. Furthermore, the microbial carrier has an effect of trapping the filamentous fungi causing the bulking phenomenon, so that a stable treated water quality can be ensured and the operation management becomes easy as compared with the activated sludge method.

Finally, the procedure of the chemical cleaning of the separation membrane is as follows. Frequency of cleaning: about once every 1 to 3 months Time required: about 3 hours per time Cleaning chemicals: 2% NaOH or 1% H ₂ O ₂ Other than acid, sodium hypochlorite, etc.

[0040]

As is clear from the above description, according to the present invention, the following excellent effects can be expected. (1) Suspended microorganisms (activated sludge microorganisms) in the membrane aeration tank
Are suspended, but when the humus pellets are put into the membrane aeration tank, soil bacteria are activated and become dominant. In addition, due to the action of the activated soil bacteria, as shown in FIG. 3, the COD removal rate is significantly increased and the removal rate is significantly increased as compared with the conventional activated sludge method. (2) When the humus pellets are put in the membrane aeration tank, the suspended microorganisms in the membrane aeration tank become the dominant species of the soil bacteria, and the soil on the membrane is reduced due to the characteristics of the soil bacteria. As a result, even when the sludge concentration is 10,000 to 12,000 ppm, membrane clogging is small, and the amount of aeration and washing air is reduced to 6 to 8 l / min compared to 10 to 15 l / min in the conventional treatment with activated sludge microorganisms. I have. (3) When a nonwoven fabric carrier is placed in a membrane aeration tank, various excellent microorganisms are adhered and held in the carrier and proliferate, so that the load on the separation membrane can be reduced. (4) Further, as shown in FIG. 4, the increase in MLSS is lower than that of the activated sludge microorganisms, and has a high effect on sludge desolubilization.

[Brief description of the drawings]

FIG. 1 is a flow sheet of a cleaning plant wastewater treatment system according to one embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration of an example of a membrane aeration tank constituting a system of the present invention.

FIG. 3 is a graph showing a COD processing effect obtained by one embodiment of the present invention.

FIG. 4 is a graph showing the change over time of MLSS obtained according to one example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Factory wastewater 2 Adjustment tank 3 Membrane aeration tank 4 Water supply pump 5 Partition plate 6 Humus pellet (humus) 7 Suction pump 8 Separation membrane 9 Activated carbon tower 10 Treated water pump 11 Treated water tank 12 Aeration tube 13 Microorganism carrier (nonwoven fabric)

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C02F 9/00 503 C02F 9/00 503C 504 504A // D06F 43/08 D06F 43/08 G (58) Fields surveyed (Int. Cl ^6, DB name) C02F 3/02 -. 3/12 C02F 9/00 501 - 504 D06F 43/08

Claims (1)

(57) [Claims] 1. A membrane provided with a regulating tank, a humus pellet, a microbial carrier such as a nonwoven fabric, a separation membrane structure formed into a cylindrical shape or a flat shape, and an air diffuser for supplying aerated air. A cleaning plant wastewater treatment system comprising an aeration tank, an activated carbon tower and peripheral equipment.