KR20010027542A - Method for purifying stinking gas simultaneously with wastewater treatment - Google Patents

Abstract

PURPOSE: Provided is a method for treating wastewater and purifying odor simultaneously by supplying odor containing a nitrogenous compound, a sulfur compound, and a volatile organic compound instead of process air in wastewater treatment using conventional aerobic biofiltration system without an additional equipment. CONSTITUTION: The method is performed by a wastewater treatment apparatus comprising: i) a base part(11) and a reaction tank(10) including a plate(12) that is placed at the top of a set distance from the base part(11) and forms a bottom chamber(13) with the base part(11); ii) a filter media layer(22) at the top of the plate(12); iii) a liquid introduction device(18) supplying wastewater to be treated to the bottom chamber(13) in normal operation, and backwash water in backwash; iv) a process air introduction device(14) supplying process air to the filter media layer(22) on the plate(12) in normal operation; v) a plurality of air diffusers(40) mounted at many ventilation pipes(42) connected with the process air introduction device(14); vi) a backwash air introduction device(16) supplying backwash air to the bottom chamber(13) in backwash; vii) a plurality of nozzles(30) passing the plate(12) and spreading from the bottom chamber(13) to the filter media layer(22); and viii) a wastewater discharge device(20) discharging wastewater treated by the filter media layer(22).

Description

Method for purifying stinking gas simultaneously with wastewater treatment

The present invention relates to a method for purifying malodorous gas simultaneously with wastewater treatment using aerobic biofiltration. The wastewater treatment process using aerobic biofiltration is a process for purifying wastewater using the filtration function of the fixed bed carrier and the organic matter decomposition ability of the microbial membrane, and must maintain the aerobic state for proper growth of aerobic microorganisms. Therefore, wastewater treatment processes using aerobic biofiltration generally require air supply.

On the other hand, significant odorous gases are emitted from manure treatment plants, sewage treatment plants, and industrial water pollution prevention facilities, which are environmental foundations. Among the odorous gas components, odor causing substances are mainly volatile organic compounds including sulfur compounds such as hydrogen sulfide and mercaptan, nitrogen compounds such as ammonia and amine, benzene, toluene, ethylbenzene, and xylene. VOC) or Volatile Sulfur Compounds. That is, since the odor component is very diverse and the production concentration also changes from time to time, it is difficult to purify the odor gas.

Such odor gas purification methods are classified into physical and chemical biological methods, and widely used methods include activated carbon adsorption, chemical liquid cleaning, aeration tank deodorization, soil deodorization, combustion, washing, masking, and the like.

However, since the physicochemical method using the chemicals has problems such as excessive maintenance cost, operation cost, and secondary treatment due to the chemical cost, interest in biological methods that enable low-cost and stable treatment is increasing day by day. .

The biological method of the odor removal process is aeration tank deodorization process. That is, the wastewater treatment process is largely divided into anaerobic and aerobic processes, and among them, the aerobic process can be further classified into activated sludge and biofiltration. The activated sludge method uses an aeration tank for supplying air for the growth of aerobic microorganisms, and the aeration tank deodorization process is a process of simultaneously treating wastewater and odor gas by injecting odor gas instead of air into the aeration tank.

As such, the existing biological malodorous gas purification process is limited to the wastewater treatment process using the floating bed activated sludge method, and there is no mention of the method of simultaneously treating the wastewater treatment and the malodorous gas purification by the biofiltration method. .

Accordingly, the present invention is to provide a method for purifying odorous gas generated in an environmental foundation such as a sewage treatment plant, a manure treatment facility, or a wastewater treatment process simultaneously with wastewater treatment using an aerobic biofiltration process.

1 is a schematic cross-sectional view illustrating the structure of a device used to practice the method of the present invention.

<Description of the code | symbol about the principal part of drawing>

10 ... reactor 11 ... base

12 ... plate 13 ... lower chamber

14 ... Means for introducing odor gas 16 ... Means for introducing back air

18 ... liquid introduction means ...

20 ... Method of discharging water 21 ... Support layer

22 ... media layer 30 ... nozzle

40 ... diffuser 42 ... vent

The present invention to achieve the above technical problem,

In the wastewater treatment using an aerobic biofiltration system, a odor gas containing nitrogen compounds, sulfur compounds or volatile organic compounds is supplied instead of process air, and a method for purifying odor gas simultaneously with wastewater treatment is provided.

Wastewater treatment using the aerobic biofiltration system,

A reaction tank including a base portion and a plate positioned at an upper portion separated from the base portion by a predetermined distance and forming a lower chamber together with the base portion; A mediator layer supported on the plate by the plate; Liquid introduction means for supplying wastewater to be treated in normal operation and backwashing water to the lower chamber during backwashing; Process air introduction means for supplying process air to the media layer above the plate during normal operation; A plurality of diffusers positioned at an upper part spaced apart from the plate and mounted to a plurality of vent pipes communicating with the process air introduction means; Backwash air introduction means for supplying backwash air to the lower chamber during backwashing; A plurality of nozzles passing through the plate and extending from the lower chamber to the media layer; And it is preferably carried out by the wastewater treatment apparatus comprising a means for discharging the treated wastewater through the filter media layer.

The air diffuser is a device capable of uniformly supplying the odor gas in the form of fine bubbles in normal operation to form an optimum condition for the growth of microorganisms, and at the time of backwashing, means for preventing backflow of the treated wastewater even if the odor gas is blocked. It is preferable to have a.

In the filter medium, the wastewater to be treated and the malodorous gas pass upward during normal operation, and the backwash air or the backwash water passes upward during backwashing.

The nozzle supplies waste water to be treated during normal operation, and backwash air or backwash water from the lower chamber to back the filter layer during backwashing, and an air layer having a predetermined height may be formed under the plate when backwashing air is injected. It is desirable to provide a means for supplying a back air of sufficient pressure to expand the media layer.

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

The aerobic biofiltration system is capable of high load operation by filling the reactor with filter medium and then attaching and growing microorganisms. It is an advanced wastewater treatment system that does not need separate sedimentation tank because of the excellent water quality and filtration function of media.

In addition, the aerobic biofiltration system removes some ammonia nitrogen by simultaneously carrying out organic matter removal and nitrification reactions in one reactor, and thus has an advantage of a small site requirement and high decontamination efficiency.

In addition, aerobic biofiltration systems are divided into upflow and downflow. Upflow refers to a system in which the wastewater to be treated is supplied upwards in the same manner as air, and downflow refers to a system in which the wastewater to be treated is supplied downward and air is supplied upward.

The method of fluid supply is directly related to the technical problem of the equal distribution of influent wastewater and air. The downflow type has a limitation in the processable flow rate because the upper layer of the media is easily clogged as the processing flow rate increases. Therefore, interest in the upflow upflow aerobic biofiltration system is increasing day by day, and it is possible to supply a process air and back-air by using a nozzle to control the size of air bubbles to maximize the oxygen transfer rate and to provide stable operation. It is widely studied.

Therefore, as of November 30, 1998, the applicant has filed a patent for a wastewater treatment apparatus using an aerobic biofiltration system (Korean Patent Application No. 98-51858). 1 is a view schematically showing the structure of a wastewater treatment apparatus using the aerobic biofiltration system of No. 98-51858.

The device of FIG. 1 is also characterized by using the diffuser device and nozzles of the applicant's patent applications 98-27898 and 98-27899.

That is, the present invention intends to use the wastewater treatment apparatus using the aerobic biofiltration system of the present patent application No. 98-51858 for the purpose of purifying the odor gas at the same time as the wastewater treatment. The apparatus includes an diffuser device 40 capable of supplying fine air bubbles to the filter medium layer 22 in an equal manner. In the present invention, an odor gas containing odor components is supplied instead of air.

Odor gas is generally capable of serving as an oxygen source since there is little difference in oxygen content compared to process air. That is, volatile organic compounds or sulfur compounds that are odorous components in the malodorous gas are ingested by microorganisms as a nutrient source, and oxygen serves as process air.

Therefore, the wastewater treatment apparatus is capable of high load operation because a large amount of microorganisms can be grown by filling a filter medium in a reaction tank to attach and grow microorganisms. The water quality of the treated water is excellent and the filtration function of the filter media does not require a separate settling tank, which serves as an economical and effective bio-trickle filter.

In the above, only the case of using the apparatus disclosed in the Applicant's No. 98-51858 has been described as an example, the principle of the present invention can be applied to any apparatus using an aerobic saline filtration system, even if not necessarily the apparatus.

Hereinafter will be described with reference to the embodiment in order to help the understanding of the present invention. The following examples are merely exemplary and the present invention is not limited thereto.

<Example>

Using the same apparatus as shown in FIG. 1, odorous gases and sewage wastewater generated in an actual wastewater treatment plant of 100-200 ppm ammonia, 70-150 ppm trimethylamine, and 50-100 ppm H2S were treated under the following operating conditions.

Sewage water flow rate 6 ml / min

Hydraulic load 0.18 m ³ / m ³ / hr

Volume load 2.16 kgCOD / m ³ / d

Hydraulic residence time 1.6 hr

24 hr backwash cycle

Process air flow 0.06 m ³ / hr

Height of the media layer 30 cm (20 cm ² )

Ammonia Nitrogen Load 0.26 kg NH ₄ -N / m ³ / d

The characteristics and treatment results of the treated sewage and gas are shown in Table 1 below.

division Statue inflow Outflow Removal rate () Waste water pH 8.47 7.21 - TCOD _cr (mg / l) 46.0 25.0 46 NH ₄ -N (mg / l) 15.0 1.5 90 NO ₃ -N (mg / l) 1.0 18.0 - gas Ammonia (ppm) 120 0 100 Triethylamine (ppm) 97 0.5 99 H ₂ S (ppm) 100 30 70

According to Table 1, it can be seen that together with the nitrification of ammonia nitrogen in the wastewater, nitrogen-based odor gases such as ammonia and trimethylamine can also be purified by nitrifying microorganisms of 99 or more.

According to the method of the present invention, since the wastewater and the odor gas can be treated simultaneously by using the existing biofiltration process without additional equipment, the operation cost is low and the maintenance of the process is easy.

Claims (5)

A method of purifying malodorous gases simultaneously with wastewater treatment, characterized in that, in treating wastewater using an aerobic biofiltration system, odorous gases containing nitrogen compounds, sulfur compounds or volatile organic compounds are supplied instead of process air. According to claim 1, Wastewater treatment using the aerobic biofiltration system, A reaction tank including a base portion and a plate positioned at an upper portion separated from the base portion by a predetermined distance and forming a lower chamber together with the base portion; A mediator layer supported on the plate by the plate; Liquid introduction means for supplying wastewater to be treated in normal operation and backwashing water to the lower chamber during backwashing; Process air introduction means for supplying process air to the media layer above the plate during normal operation; A plurality of diffusers positioned at an upper part spaced apart from the plate and mounted to a plurality of vent pipes communicating with the process air introduction means; Backwash air introduction means for supplying backwash air to the lower chamber during backwashing; A plurality of nozzles passing through the plate and extending from the lower chamber to the media layer; And means for discharging the treated wastewater through the filter media layer. According to claim 2, wherein the air diffuser is uniformly supplying the odor gas in the form of fine bubbles during normal operation to form the optimum conditions for the growth of microorganisms, and backwashing the treated wastewater even if the odor gas is blocked during backwashing Method comprising a means for preventing the. The method of claim 2, wherein the filter layer is characterized in that the wastewater and odor gas to be treated in the normal operation passes upward, the backwash air or backwash water passes upward during backwashing. 3. The nozzle of claim 2, wherein the nozzle supplies waste water to be treated during normal operation, and backwash air or backwash water from the lower chamber to the media layer during backwashing, and at a predetermined height under the plate when injecting backwash air. And a means capable of forming an air layer to supply backpressure of sufficient pressure to inflate the media layer.