JPH10156390A - Treatment of ammonia-containing fluid waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To biologically treat a fluid waste without the function being lowered by evaporating and separating the fluid waste into the condensate and evaporation residue and separating the condensate into an ammonia-contg. steam or ammonia-contg. water by distillation. SOLUTION: An ammonia-contg. waste water and a fluid waste 10 are introduced into a solid separator 1 to separate the contained coarse solid material, then supplied to a thin-film evaporator 2 and separated into a condensate 12 contg. a volatile component including ammonia and an evaporation residue 11 consisting of the solid component and nonvolatile component. The condensate 12 is introduced into an ammonia concentrator 3 and separated into an ammonia-contg. steam or aq. ammonia 13 and the residue 14, and the separated ammonia-contg. steam or aq. ammonia 13 is oxidized and decomposed in a catalytic oxidation device 5. Meanwhile, the residue 14 is introduced into a biological treating device 6, and the treated water from the device 6 is treated with activated carbon and recycled or discharged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating fluid waste, and more particularly, to a method for treating wastewater containing ammonia and waste containing a large amount of muddy (slurry) water.

[0002]

2. Description of the Related Art The properties of leachate in landfills of general waste and industrial waste, sludge currently designated as industrial waste, and wastewater in animal manure are characterized by high concentrations of BOD, COD,
It has the characteristics of containing SS, containing ammonia, and having a large range of concentration fluctuation.
The equipment for removing D, COD and SS is installed double or triple to comply with the regulation value of treated water. An example is as follows. ○ Removal of BOD: Combination of floating biological treatment (so-called activated sludge equipment) and biofilm-type biological treatment equipment such as rotating disks and catalytic oxidation. ○ Removal of COD: Combination of condensation and precipitation treatment with ozone oxidation equipment and activated carbon adsorption equipment. ○ Removal of SS: Combination of dewatering equipment, coagulation sedimentation equipment and filtration equipment.

[0003] As described above, even if a large number of facilities are installed, fluctuations in the properties of the wastewater flowing into the facilities must be operated by management techniques based on the long-term experience of many operation managers. In addition, there are problems in that a large amount of chemicals are used in the biological treatment and coagulation sedimentation treatment, and excess sludge is generated due to the use of many chemicals. In addition, when heavy metals are contained in the wastewater, a new chelate resin facility is required, and management and treatment of the used chelate resin are required.
Ammonia contained in wastewater acts as a poison for microorganisms used in biological treatment, and if introduced at a high concentration, inhibits metabolism in the biological treatment process.

An aerobic biofiltration apparatus capable of directly treating the high-concentration wastewater as long as the wastewater has a relatively low ammonia content is being developed. However, especially waste such as wastewater and slurry containing a large amount of solids cannot be treated.Efficient treatment is achieved by evaporating and recovering volatile components and treating them separately from the residue. A technique that can be performed has been proposed (see Japanese Patent Application No. Hei 7-23280). However, also in the above-mentioned technology, ammonia is present in a portion to be evaporated and collected, and condensed water having a high ratio of ammonia to organic matter is generated. Therefore, there is a problem that a large amount of ammonia inhibits the subsequent biological treatment.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, facilitates the operation of the treatment, and removes the liquid waste without deteriorating the function of the biological treatment based on the inhibition of metabolism by ammonia in the treatment of organic substances. An object of the present invention is to provide a method for treating an object.

[0006]

In order to solve the above-mentioned problems, the present invention is characterized in that a fluid waste containing ammonia is sequentially treated in the following steps (a) to (c). It is a method for treating fluid waste. (A) a first separation step of evaporating a fluid waste containing ammonia and separating it into an evaporative condensate containing a volatile component containing ammonia and an evaporation residue consisting of a solid content and a non-volatile component; b) a second separation step of further distilling the evaporated condensate of the step (a) into ammonia-containing steam or ammonia-containing water (hereinafter referred to as "aqueous water") and a residue; b) a catalytic oxidation step of catalytically oxidizing the ammonia-containing steam or the ammonia-containing water in the step.

In the above treatment method, the catalytic oxidation step (c) includes a first catalytic oxidation step of decomposing the volatile organic matter in the ammonia-containing vapor or water and a second catalytic oxidation step of decomposing the ammonia. Good to have. Further, the evaporation residue in the step (a) and / or the residue in the step (b) can be aerobicly biologically treated, and the biologically treated water is preferably subjected to activated carbon adsorption treatment. .

[0008]

Next, the present invention will be described in detail.
The present invention extracts ammonia in fluid waste in the form of ammonia-containing steam or low-temperature water and performs catalytic oxidation to efficiently remove ammonia, and is derived from volatile substances such as coexisting organic acids. BOD can be treated without being inhibited by biological treatment. The fluid wastes that can be treated in the present invention include waste fluids containing ammonia together with high concentrations of BOD, COD and SS, especially leachate, sludge, manure, and the like from landfills.
The present invention can be suitably applied to waste liquids containing a large amount of solids such as industrial waste liquids and wastes such as slurries. When the waste contains a large amount of coarse solids or the like, a solid-liquid separation step such as precipitation separation or centrifugation may be provided as a pretreatment.

In the first separation step of the step (a) of the present invention, a known evaporating and condensing apparatus and a known distillation apparatus are used. In particular, a thin-film falling-down evaporating apparatus is a preferable example.
In the evaporative condensate obtained in the step (a), ammonia is contained together with substances such as volatile organic acids contained in waste such as waste liquid. Further, the evaporation residue contains SS, salt, and non-volatile contaminants (organic and inorganic substances). These evaporation residues may be treated by a dehydration / drying treatment, or when there are few harmful substances such as heavy metals and a lot of organic substances, they can be treated by leading to an aerobic biological treatment step. The evaporative condensate generated in the step (a) is introduced to the second separation step in the step (b). In the step (b), an ammonia concentrator is used. The ammonia concentrator is a device composed of a distillation column using steam and a condenser, and utilizes the difference in vapor pressure while the evaporating condensate flows between the packing materials filled in the distillation column. The contained ammonia becomes gas and is removed. The removed ammonia is cooled by a condenser, and concentrated and recovered as about 1 to 10% low-temperature water.

In this process, 90% of the ammonia in the raw waste is removed.
About 98% is removed. At this time, the reaction conditions in the ammonia concentrator are as follows:
Preferably it is around 80 ° C. Therefore, some of the volatile substances (organic acids and the like) contained in the evaporative condensate also move into the low-temperature water. A very small amount of ammonia remains in the residue in the step (b), but the amount is not enough to inhibit the activity of the aerobic microorganism. Therefore, volatile substances such as organic acids in the residue can be efficiently treated in the subsequent biological treatment step. In the biological treatment step, an aerobic biological filter method is preferably used. In addition, as a more advanced treatment, adsorption treatment is performed by passing through an activated carbon tower to remove chromaticity, trace COD, and the like.

On the other hand, concentrated ammonia at a level of several percent is present in the ammonia-containing steam or the aqua water obtained in the step (b), and these are decomposed in the catalytic oxidation step of the next step (c), It becomes gas and water (H ₂ O) and is released into the environment. When performing catalytic oxidation, a part of the distillation components is condensed and returned to the distillation column (generally referred to as reflux). In addition, most of the gas is introduced into the catalytic oxidation device as it is, so as to perform oxidative decomposition in a gas state. (C)
The ammonia oxidation decomposition catalyst used in the process is a platinum catalyst,
For example, it can be suitably used in a honeycomb shape or the like. In addition, some volatile substances such as organic acids may coexist in the above-mentioned water, and therefore it is necessary to remove these organic components prior to ammonia oxidative decomposition. For this reason, it is preferable that the catalytic oxidation step be a two-stage treatment, in which the organic matter is first decomposed by the Fe / Me catalyst (preferably in the form of pellets), and then the ammonia oxidative decomposition by the platinum catalyst is performed.

Next, the present invention will be described with reference to the drawings. FIG. 1 shows an overall configuration diagram of an apparatus using the processing method of the present invention. In FIG. 1, 1 is a solids separation device, 2 is a thin film falling-down type evaporator for performing the first separation step of step (a), 3
Is a distillation column for performing the second separation step of step (b), 4 is a condenser, and these 3 and 4 constitute an ammonia concentrator, and 5 is a catalytic oxidation apparatus for performing the catalytic oxidation step of step (c). , 6 are biological treatment devices. The fluid waste 10 is separated into coarse solids by the solid separation device 1,
It is introduced into the thin film falling-down type evaporator 2 and is separated into an evaporating liquid 12 containing a volatile component including ammonia and an evaporation residue 11 composed of a solid component and a non-volatile component. The evaporating liquid 12 is introduced into the ammonia concentrator 3 and separated into ammonia-containing steam or low-temperature water 13 and a residue 14. Ammonia and organic matter are oxidized and decomposed in the catalytic oxidation device 5 in the ammonia-containing steam or the low-temperature water.

FIG. 2 is an enlarged view of the ammonia removing portion. As shown in FIG. 2, the ammonia concentrator 7 includes a distillation column 3 in which a bottom portion is heated to steam 16 and a filler 8 is filled therein, and a condenser 4 that condenses vapor from the distillation column 3. I have. The ammonia-containing steam or the low-temperature water is introduced into the catalytic oxidizer 5 to oxidize and decompose the ammonia, and the low-temperature water 13
Is partially recycled to the distillation column. On the other hand, the remaining 14
Is introduced into the biological treatment apparatus 6 for biological treatment. Treated water from the biological treatment device is reused or discharged as it is or after activated carbon treatment. At this time, when the evaporation residue 11 contains almost no organic components, it is disposed without being introduced into the biological treatment step. In addition, the ammonia concentration of each stage is 50-1000 mg / liter of raw water, 0.5-
It can be 10%, the secondary residue 10 to 100 mg / liter.

[0014]

The present invention will be described below in more detail with reference to examples. Example 1 Leachate from a waste disposal site was treated as raw water using the apparatus shown in FIG. The properties of raw water are as follows. pH (-): 7.4 BOD ( mg / l): 350 COD (mg / l): 656 TOC (mg / l): 539 SS (mg / l): - Cl (mg / l): 4740 NH ₃ -N (mg / liter): 512

Since this raw water does not contain coarse solids, it was directly introduced into a thin film falling evaporator for treatment. The properties of the obtained distillate are as follows. pH (-): 10 BOD ( mg / l): <5 COD (mg / l): 32 TOC (mg / l): <5 Cl (mg / _{l): <100 NH 3 -N (} mg / l) : 348 Next, the distillate was distilled using an ammonia concentrator. The properties of the distillate, which is an aqua water, were as follows. _{NH 3 -N: 1.9% TOC:} 1%

The low-temperature water is subjected to catalytic oxidation at the first stage in a catalytic oxidation device.
Using an e / Mn-pellet catalyst and a platinum honeycomb catalyst in the second stage, organic substances were oxidized in the first stage and ammonia was oxidized in the second stage. As a result, the ammonia decomposition rate was 99.97.
%, A TOC decomposition rate of 99.95%. On the other hand, the residue from the ammonia concentrator had the following properties. pH (-): 9.7 BOD (mg / liter): <5 COD (mg / liter):-TOC (mg / liter): 15.6 SS (mg / liter): <5 Cl (mg / liter) _{: <100 NH 3 -N (mg} / l): 12

Next, this residue was subjected to biological treatment in an aerobic biological filter, followed by activated carbon adsorption treatment. Table 1 shows the properties of each treated water.

[Table 1]

[0018]

According to the present invention, the following effects can be obtained. (1) By separating and recovering ammonia by distillation, (a) By combining with a thin film falling down type evaporator,
Highly volatile substances such as ammonia and organic acids can be efficiently taken out and processed. (B) High removal efficiency can be obtained regardless of the ammonia concentration. (C) Compared with biological denitrification treatment, the apparatus is compact and equipment costs are low. (D) There is no need to use chemicals such as methanol and caustic soda as in the biological denitrification treatment. (E) If the ammonia concentration exceeds 100 mg / liter, it becomes an inhibiting factor for biological treatment.

(2) By performing the catalytic oxidation treatment, (a) the decomposition efficiency of ammonia is as high as 99.9% or more. (B) By combining the Fe / Mn catalyst and the platinum catalyst, the apparatus is compact and the equipment cost is low. (C) By combining the Fe / Mn catalyst and the platinum catalyst, organic substances other than ammonia contained in the ammonia water can be efficiently removed, and stable decomposition efficiency can be obtained.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an example of an apparatus used for a processing method of the present invention.

FIG. 2 is an enlarged configuration diagram of an ammonia removing portion in FIG. 1;

[Explanation of symbols]

1: solid substance separation device, 2: thin film falling evaporator, 3: distillation column, 4: condenser, 5: catalytic oxidation device, 6: biological treatment device, 7: ammonia concentrator, 8: packing material

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C02F 1/28 C02F 1/58 CDJP 1/58 CDJ 3/02 Z 3/02 11/12 A 11/12 B01D 53/36 ZABE

Claims (4)

[Claims] 1. A flowable waste containing ammonia,
A method for treating fluid waste, comprising sequentially treating in the following steps (a) to (c). (A) a first separation step of evaporating a fluid waste containing ammonia and separating it into an evaporative condensate containing a volatile component containing ammonia and an evaporation residue consisting of a solid content and a non-volatile component; b) The evaporative condensate of the step (a) is further distilled to obtain ammonia-containing steam or ammonia-containing water;
(C) a catalytic oxidation step of catalytically oxidizing the ammonia-containing steam or ammonia-containing water of the step (b). 2. The catalyst oxidation step (c) includes a first catalyst oxidation step of decomposing volatile organic substances in the ammonia-containing vapor or the ammonia-containing water, and a second catalyst oxidation step of decomposing ammonia. The method for treating fluid waste according to claim 1, wherein: 3. The fluid waste according to claim 1, wherein the evaporation residue in the step (a) and / or the residue in the step (b) are subjected to aerobic biological treatment. Processing method. 4. The method according to claim 3, wherein the biologically treated water is subjected to activated carbon adsorption treatment.