JPH04305300A - Waste water treating device - Google Patents

Abstract

PURPOSE:To provide the waste water treating device which can inexpensively purify the waste water from hotels, restaurants, etc., having relatively high BOD, COD, SS, etc. CONSTITUTION:This device has a water receiving tank (1) which receives the raw water of waste water, an aeration tank (2) which can make superconvectional aeration by fine bubbles, a reaction chamber (3) which subjects sludge to flotation in an acid or alkaline soln. then to neutralization and sends this sludge to the ensuing stage, a settling sepn. chamber (4) which separates the materials contained in the sludge by utilizing the sp. gr. differences, a treated water tank (5), a sand filter column (6), and a multistage type active carbon filter column (7).

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wastewater treatment system having an aeration tank and a plurality of filtration towers.

0002

[Prior Art] In general, in wastewater treatment, if physical treatment or chemical treatment is applied, the wastewater treatment time can be relatively short and the equipment itself can be small-scale, but it has the disadvantage of high operating costs. . By the way, the state of existence of pollutants in wastewater is roughly divided into suspended substances and dissolved substances. Suspended substances are metals, metal oxides, poorly soluble compounds, organic polymer substances, etc. that do not dissociate into molecules or ions in water, so by utilizing their physical properties, Processing technology based on solid-liquid separation is applied.

On the other hand, dissolved substances often consist of inorganic metal ions and organic soluble compounds, and it is first necessary to convert the dissolved substances into insoluble substances and also to harmless substances, and after this, solid-liquid separation is performed. Processing techniques will be applied.

0004

[Problems to be Solved by the Invention] These conventional wastewater treatment methods require large-scale equipment, use a large amount of chemicals, and have the disadvantage of increasing operating costs. There are many problems such as the difficulty of safely disposing of these, and an early solution to these problems is desired.

[0005] The present invention provides a treatment device having a function that can be used for a wide range of wastewater treatment, such as treatment of industrial wastewater and domestic wastewater, which contain a large amount of dissolved substances consisting of organic soluble compounds and inorganic metal ions. BOD, COD, SS
The purpose of this project is to provide an optimal treatment device for purifying wastewater from relatively expensive cafeterias, etc.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the wastewater treatment device of the present invention is equipped with a fine diameter bubble injection equipment for aeration, and a sand filter tower is installed on the upstream side for filtration. The present invention is characterized in that a plurality of filtration towers are connected on the downstream side so that the filtration tower filled with the latest filtration agent becomes the final filtration order by valve switching.

[0007]

[Function] According to the wastewater treatment apparatus constructed as described above, aeration is carried out by air bubbles of fine diameter that are injected upward from the bottom of the aeration tank, so that it is carried out extremely efficiently. In addition, filtration is performed using a sand filtration tower and a multi-stage activated carbon filtration tower, and in the activated carbon filtration tower, the flow path is switched so that the filtration tower filled with new activated carbon is always at the last stage, so the activated carbon filtration tower The overall filtration efficiency remains constant at all times.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic diagram of a wastewater treatment apparatus showing an embodiment of the present invention. In the figure, 1 is a receiving tank for sewage discharged from cafeterias, etc., 2 is an aeration tank, 3 is a reaction tank in which sludge is floated and separated in acid or alkaline liquid, neutralized, and sent to the next process, and 4 is sewage water. 5 is a treated water tank, 6 is a sand filtration tower, 7 is a multistage activated carbon filtration tower, 8 is a sludge tank, and 9 is a connection between each device. It's plumbing.

First, the process of wastewater treatment will be explained based on the drawings. Sewage discharged from the cafeteria and stored in the water receiving tank 1 is flowed into the aeration tank 2 by the pump P. For aeration, air pressurized by a compressor 21 is sent to a gas outlet 22.
to fine bubbles (e.g. 0.1-0.2 microns in diameter)
The so-called wet high-pressure oxidation method, which has a structure in which water is ejected into the sewage inside the tank, may be used. However, as shown in the figure, this method is a method in which the water is ejected upward from the bottom side of the water receiving tank 2. It is preferable to use a sewage system, which injects air forcefully upwards against the wastewater flowing in the falling direction, and because it is a facing method known as "super convection aeration", there is more gas-liquid contact and oxidation by air is prevented. The action is significantly accelerated and the aeration effect is improved. Therefore, in conventional aeration, the sludge adsorbs organic matter in the sewage, gradually oxidizes and decomposes it, causes the sludge to settle, and the supernatant liquid is discharged or sent to the next treatment process, but the present invention On the other hand, microbubbles are attached to the suspended solids in the inflowing wastewater to reduce their apparent specific gravity, and the floating substances are separated by flotation. It is designed to be discharged outside the tank. Note that an aeration time of about 6 hours is usually sufficient.

[0010] Furthermore, BOD and COD are 1000 ppm.
For wastewater containing the above, it is extremely efficient to use ozone instead of air, and it is possible to shorten aeration time and tank retention time, which is extremely efficient. If the pressure levitation method is applied to this, the effect will be even more remarkable.

[0011] The liquid that has been primarily treated by aeration flows into the acid treatment tank 31 of the reaction tank 3 through the pipe 9 by the pump P. In the chemical liquid tank 32, a 25% sulfuric acid solution or "ROX (trade name)" liquid is prepared as an acidic chemical. This "ROX" is manufactured by extracting weathered granite, serpentinite, etc. with sulfuric acid, and an acidic agent is added and adjusted to create an acidic liquid that corresponds to the characteristics of the molten metal ions and molten substances, respectively, and is mixed with a stirrer 33. Stir thoroughly. As a result, suspended particles of fine particles are aggregated, speeding up the sedimentation rate, and flowing into the next alkaline treatment tank 34, where the chemical solution tank 35
Araleite-based limestone (naturally occurring orthorhombic calcium carbonate, purity 98%) or slaked lime, which is an alkaline agent stored in At this time, the molten organic matter is further coagulated and extracted, and the treated liquid is further neutralized according to the commands of the pH meter. Mechanisms for discharging floats generated in the first and second stages of this secondary treatment to the outside of the tank are not shown. It should be noted that since there is no need to add other special coagulants to acidic, alkaline, etc. chemicals, the amount of sludge produced is extremely small, making the injection of chemicals economical. In addition, although it is possible to extract settled sludge in this process, due to the fact that it is at the bottom of the tank, the operation of the agitator 33, and the residence time, sludge is not discharged in this process, and the sludge is not discharged in the next process. Since the separation is carried out all at once in the separation tank 4, the separation is effective and reliable, and is extremely economical.

In the sedimentation separation tank 4, mainly the coagulated sludge of the secondary treatment liquid is sedimented and concentrated, and the discharger 41 is operated to remove the sludge from the sludge tank 81 of the sludge treatment device 8 outside the tank.
This sludge is turned into granules that can be conveniently transported by a compression dewatering and drying mechanism 82, and is used as fertilizer or discarded.

The liquid that has undergone the tertiary treatment in the sedimentation separation tank 4 is
Furthermore, it enters the treated water tank 5. This tank 5 is installed to obtain a higher quality of water by chemical treatment, residence time treatment, and filtration treatment as necessary.

[0014] In order to obtain clear water by further removing trace amounts of suspended solids that could not be removed in the previous step up to the treated water tank 5,
Final treatment is performed first in a sand filtration tower 6 and then in a multi-stage activated carbon filtration tower 7. This combination is also a device for preventing early deterioration of activated carbon due to direct activated carbon filtration. Of course, it is also possible to mix and use.

Although three multi-stage activated carbon filtration towers 7 for the final stage are provided in this embodiment, a plurality of them may be used. First, water sent from the sand filtration tower 6 passes through, for example, pipes 9 installed in multiple rows, and is transferred to the first tower 72, second tower 73, and third tower 74 of the activated carbon filtration tower by operating a plurality of switching valves 71. It is designed to be passed through and filtered based on the ranking. The order of the columns is determined by switching a plurality of switching valves 71 so that new filtering agent (activated carbon) 75 is passed through the column after the column filled with it. That is, when the activated carbon 75 packed in the first column 72 adsorbs organic matter and reaches a breakthrough point, the activated carbon 75 is replaced with fresh carbon, and water is then passed through the second column 73, the third column 74, and the first column. The order is switched to tower 72. This suppresses fluctuations in the adsorption power of the multi-stage activated carbon filtration tower 7 as a whole, making it possible to always maintain the desired adsorption efficiency. In this way, the purified water that has passed through the multi-stage activated carbon filtration tank 7 is purified to a standard value or a desired value and is discharged to the drain port 76. Here, it is efficient to use activated carbon manufactured from coconut shells as the activated carbon to be filled. In addition, in this example, the third tank was always used, but one tank was kept as a reserve and replaced when the tower in which the activated carbon 75 reached the breakthrough point was removed from the flow path. You are also free to change the order of water flow. In addition, this activated carbon filtration process mainly removes organic substances, COD, BOD, and SS that were not extracted by the above mechanism, adsorbs and removes normal hexane and residual chlorine, which are relatively abundant in waste water from cafeterias, etc. Of course, deodorization, decolorization, desulfurization, etc. are performed.

[0016]

[Effects of the Invention] As described above, in the wastewater treatment apparatus according to the present invention, firstly, fine air bubbles are ejected in the aeration tank in the opposite direction to the flow of wastewater, so that gas and liquid come into sufficient contact with each other. Therefore, oxidation is sufficiently promoted even with a residence time of several hours, and the oxides are floated and discharged, so there is no need to install equipment to take out the sediment from the bottom of the tank, as is the case with sinking discharge, making it economical. Particularly in the case of wastewater with high BOD and COD, ozone can be used instead of air to promote oxidation, and the multi-stage activated carbon filtration tower in the final stage can freely switch the water flow order by operating the switching valve. Since it was possible,
The filtration tower filled with the new activated carbon can always be placed in the final rank, thereby making it possible to maintain the activated carbon adsorption efficiency of the entire filtration mechanism so as not to fluctuate at all times. In addition, since other chemicals such as flocculants are not used, the amount of sludge can be reduced.
Depending on the chemicals used, even sludge can be used for other purposes, making it possible to carry out the desired wastewater purification economically in terms of equipment costs, operating costs, etc., and making sludge disposal and other handling extremely easy. It is.

[0017]

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a wastewater treatment device.

[Explanation of symbols]

1 Sewage receiving tank 2 Aeration tank 3 Reaction tank 4 Sedimentation separation tank 5 Processing tank 6 Sand filter tower 7 Multi-stage activated carbon filtration tower 8 Sludge treatment equipment

Claims (1)

[Claims] Claim 1: A wastewater treatment device that purifies wastewater by aeration, acid treatment, and alkali treatment and then filtering the wastewater, wherein the aeration is equipped with injection equipment for fine-diameter bubbles, and the filtration is carried out using sand on the upstream side. A wastewater treatment device comprising a filtration tower and a plurality of filtration towers connected downstream by valve switching so that the filtration tower filled with the latest filtration agent is always in the final filtration order.