KR100517095B1 - Wastewater Treatment Apparatus and Method - Google Patents

Abstract

The present invention relates to a sewage treatment apparatus and method for efficiently removing both organic matter and nutrients of sewage generated at home, the sewage treatment apparatus according to the present invention includes a primary sedimentation tank and a flow rate adjusting tank (2); First anaerobic bath (3); Second anaerobic bath (4); Activated sludge tanks 5; Contact aeration tank 6; Final settling tank 7; And microbial activator (8).

Description

Wastewater Treatment Apparatus and Method

The present invention relates to an apparatus and a method for discharging effluents by treating sewage generated at home and satisfying the Act on Sewage, Manure and Livestock Wastewater. More specifically, the present invention is to treat sewage for discharging organic matter contained in sewage discharged from the home by biological method and to discharge effluent that meets the discharge standard by removing nutrients such as nitrogen and phosphorus. An apparatus and method are provided.

Due to the rapid industrial development and the increase and concentration of the population, the environmental pollution of our country is progressing rapidly, and it is very difficult to meet the diverse and complex reality from the problems of securing drinking water, air pollution, garbage disposal, to trade regulation through environmental problems. I faced it. With the development of industry, people's awareness of environmental pollution has risen to the level of advanced countries, and the desire for a pleasant environment has been strengthened.

In particular, as seen in the recent virus detection problem in tap water, due to the spread of anxiety about the public's water and distrust of the water supplied by the government, tap water can be used to drink water or purchase bottled water in recognition that tap water is no longer drinkable. Assumptions to solve problems are also increasing. In addition, due to water pollution, rivers are not completely recovering their meaning as hydrophilic spaces.

Since Korea's first urban sewage treatment plant was constructed in 1979 to improve living environment and water quality, many sewage treatment plants have been constructed and operated throughout the country. Most of the existing sewage treatment plants and new sewage treatment plants were intended to remove organic matter and suspended solids, but the treatment of nitrogen and phosphorus has become important as a new discharge method restricts nutrients such as nitrogen and phosphorus. It became. Therefore, many researchers in the country have been researched on the biological nutrient removal method, but the situation has not been presented a complete treatment device and method.

Accordingly, it is an object of the present invention to provide an apparatus and method capable of stably and reliably treating sewage organics and nutrients.

The inventors of the present invention are the first settling tank and the flow rate adjusting tank step of equalizing the concentration and flow rate of the sewage discharged from the home to facilitate the subsequent treatment and the first precipitation of the sedimentable suspended solids; A first anoxic tank step of denitrifying nitrate nitrogen contained in the sludge returned from the final settling tank by using organic matter in the sewage flowing from the primary settling tank and the flow rate adjusting tank; A second anoxic tank step of denitrifying nitridized nitrite and nitrate nitrogen contained in the sludge introduced from the first anoxic tank and the sludge conveyed from the contact aeration tank using an organic material contained in the sludge; An active sludge tank step of oxidizing the organic matter in the sludge introduced from the second anoxic tank using the aerobic microbial group maintained at a constant concentration in the reactor and nitrifying ammonia nitrogen to nitrite nitrogen and nitrate nitrogen; A contact aeration tank step of extending the microbial retention time by using an adhesive medium and oxidizing untreated organic matter contained in the sludge flowing from the activated sludge tank and oxidizing ammonia nitrogen to nitrite nitrogen and nitrate nitrogen; A final settling tank step of separating the sludge introduced from the contact aeration tank into solids and treated water and finally discharging the sludge; And a microbial activator step of incorporating a microbial agent inoculated with soil microorganisms containing Bacillus spp. Microorganisms as inorganic and dominant species and activating the dominant species of sludge returned from the final settling tank and supplying activated sludge to the activated sludge tank. It has been found that this is achieved through a sewage treatment method according to the present invention and an apparatus for carrying out the method.

Hereinafter, the present invention will be described in detail with reference to the sewage treatment apparatus 1 shown in the accompanying drawings.

1 is a block diagram of an apparatus for treating sewage using activated sludge and adherent microorganisms according to the present invention. Since the sewage treatment apparatus 1 according to the present invention has a severe change depending on the time of day and season in the amount and concentration due to the characteristics of domestic sewage generated at home, the sedimentary precipitates are firstly removed and the burden of sedimentable sediments is reduced. Primary settling tank and flow adjusting tank (2); A first anoxic tank (3) for denitrifying nitrate nitrogen contained in the sludge returned from the final settling tank (7) using organic matter in the sewage flowing from the primary settling tank and the flow rate adjusting tank (2); A second anoxic tank (4) for denitrifying nitridated nitrite and nitrate nitrogen contained in the sludge flowing from the first anoxic tank (3) and in the sludge conveyed from the contact aeration tank (6) using organic matter contained in the sludge ; An activated sludge tank 5 for oxidizing organic matter in the sludge introduced from the second anoxic tank 4 and nitrifying ammonia nitrogen to nitrite nitrogen and nitrate nitrogen using an aerobic microorganism group maintained at a constant concentration in the reactor; The adhesion medium (15) is used to prolong the microbial residence time as much as possible, and secondary oxidation of untreated organic matter contained in the sludge flowing from the activated sludge tank (5) and oxidation of ammonia nitrogen to nitrite nitrogen and nitrate nitrogen. Contact aeration tank 6 for letting; A final settling tank 7 which separates the sludge introduced from the contact aeration tank 6 into solids and treated water and finally discharges it; A microbial activator (8) containing a microbial agent inoculated by inoculating and mass cultivating a specific soil microorganism and activating the dominant species of sludge returned from the final settling tank (7) is included.

In the sewage treatment apparatus 1 according to the present invention, the sludge conveyance and the movement route together with the movement route of the workpiece are very important, and the sludge separated into solid-liquid separated in the final sedimentation tank 7 is returned to the first anoxic tank 3 to remove denitrification. The sludge separated route from the final sedimentation tank (7) and the sludge transfer path (9), which provide the organic material for maintaining the concentration of microorganisms in the activated sludge tank (5) to the appropriate level, the microorganism activator (8) It is conveyed to the second anoxic tank (4) from the contact aeration tank (6) and the aeration line (10), which is a sludge migration route which is cultivated and the soil microorganism is cultured using the microbial agent and introduced into the aeration tank. The treatment capacity of sewage is improved through the conveying line 11, which is a sludge migration path which allows denitrified nitrogen nitrate to be denitrated with nitrogen gas.

The role and action of each reaction tank of the sewage treatment apparatus 1 according to the present invention will be described in more detail as follows. Sewage, which is to be treated, exhibits a wide variety of patterns and concentrations depending on lifestyle, dietary culture, and regional characteristics. Such changes in the amount and concentration of sewage can adversely affect the entire system when introduced into the biological sewage treatment system, resulting in a reduction in the treatment efficiency of the device. Therefore, the primary sedimentation tank and the flow regulating tank (2) serve to equalize the amount and concentration of the sewage introduced and to settle and remove the sedimentable suspended matters first. In the sewage treatment system, the primary sedimentation tank and the flow regulating tank (2) play different roles depending on the size of the sewage treatment plant. First, in a sewage treatment plant having a large treatment capacity, the sewage pipe goes through a long sewage pipe until it flows into the sewage treatment plant. Since the flow rate and concentration of the incoming sewage are kept almost constant, it acts as a primary sedimentation tank to precipitate suspended solids rather than as a flow adjustment tank. Since this is large, it will play the role of the flow adjustment tank.

The to-be-processed object which passed through the primary sedimentation tank and the flow adjusting tank (2) flows into the 1st anoxic tank (3) in which sediment sludge is conveyed from the final sedimentation tank (7) via the conveying line (9). The first anoxic tank 3 is equipped with a mixer 12 for agitation and is responsible for smooth mixing of microorganisms in the reactor and sewage. Here, the organic matter contained in the sewage is denitrated using nitrate nitrogen contained in the returned sludge. Denitrification is caused by denitrifiers, which occur in several stages. The first step is the nitrate nitrogen (NO ₃₎ is converted to nitrite nitrogen (NO _2), the nitrite nitrogen (NO ₂₎ is through a process of several steps is reduced to nitrogen gas (N _2). These two steps are called resimilation, and the path of this reaction, commonly known as

NO ₃ → NO ₂ → NO → N ₂ O → N ₂

The above denitrification is a reaction that produces alkalinity. This generation of alkalinity recovers about half of the alkalinity due to nitrification reactions occurring in the activated sludge tank 5 and the contact aeration tank 6, with an alkalinity produced per gram of nitrate nitrogen (NO ₃ -N) being 4.57 g as CaCO ₃ . Although the optimum pH varies depending on the type of microorganisms involved in denitrification or the characteristics of the sewage, a pH of about 7 to 8 is most suitable. In the apparatus according to the present invention, a separate pH for adjusting the pH in the first anoxic tank 3 is provided. It can be operated without manipulation or chemical injection.

The to-be-processed object via the 1st anoxic tank 3 flows into the 2nd anoxic tank 4, in which the sludge is conveyed from the contact aeration tank 6 via the conveying line 11. The second anoxic tank 4 is also equipped with a stirring mixer 12, which is responsible for the smooth mixing of the microorganisms in the reactor and the sewage. In the sludge conveyed from the first aerobic tank (3) and the sludge returned from the contact aeration tank (6), nitrogen nitrate was not denitrated, and organic matter was not consumed for denitrification in the first anoxic tank. In (4), such denitrified nitrate nitrogen is secondary denitrified by the denitrification microorganism. The second anaerobic tank 4 also serves as an anaerobic tank in which phosphorus release by microorganisms occurs after the introduced nitrogen nitrate is denitrated in a short time. The second anoxic tank (4) can also be operated without chemical injection or special manipulation for pH control.

The workpiece to be processed via the second anoxic tank 4 flows into the activated sludge tank 5. In the activated sludge tank 5, aerobic microorganisms and nitrifiers are present in large quantities, and these aerobic microorganisms and nitrifiers oxidize organic matter by using air continuously supplied from the blower 13 through the acid apparatus 14. Let's do it. The large molecular weight organic matter is decomposed into small molecular weight organic matter by the extracellular enzyme discharged from the aerobic microorganism present in the activated sludge tank 5, and the small molecular weight organic material is oxidized and used for the maintenance, growth and propagation of the microorganism. The reaction equation for the growth and proliferation of these microorganisms is as follows.

CHONS (organic) + O ₂ + microorganism → CO ₂ + NH ₃ + other products + energy

CHONS (organic) + O ₂ + microorganism + energy → C ₅ H ₇ O ₂ N (new microbial cells)

In addition, in the activated sludge tank (5), nitrification reaction occurs in which ammonia nitrogen is oxidized to nitrite nitrogen (NO ₂ -N) and back to nitric acid (NO ₃ -N) by the nitrifying microorganism, and H ⁺ Is produced and consumes alkalinity, which consumes an alkalinity of 7.14 g as CaCO ₃ per 1 g of ammoniacal nitrogen. Due to this alkalinity consumption, the pH in the activated sludge tank 5 is reduced. The overall reaction equation for this nitrification is as follows.

^{_{NH 4 + + 2O 2 → NO}} 3 - + 2H + + H 2 O

In addition, in the activated sludge tank (5), the uptake of phosphorus released by the microorganisms in the second anoxic tank (4) takes place. The absorption in the aerobic state following the release of phosphorus in the anaerobic state is much higher than the amount required for the cell structure of the microorganism. This is called 'luxury uptake' because it absorbs positive phosphorus. The activated sludge tank (5) also introduces sludge from the microbial activator (8), which contains a microbial agent made of several substances taken from the natural state, which contains Ca ^{2. It} contains abundant inorganic substances such as ⁺ and Mg ²⁺ and inoculates by separating and mass cultivating certain soil microorganisms including Bacillus species. The microbial activator (8) receives sewage corresponding to 1% of the flow rate flowing into the first anoxic tank (3) to supply organic matter and nutrients for the growth and propagation of microorganisms. Precipitated sludge is introduced through the return line 10, and the introduced sludge is activated by the microbial agent contained in the microorganism activator 8.

The processed material via the activated sludge tank (5) is introduced into the contact aeration tank (6), which is filled with a medium (15) for extending the retention time of the microorganism to the maximum and maintaining the concentration of the microorganism at a high concentration. The filter medium filled in the contact aeration tank 6 has a myriad of pores to which microorganisms can adhere, and preferably made of a physically and chemically safe material. The microorganisms attached to the filter medium 15 serve to decompose and remove organic substances as they grow and multiply, and to completely oxidize ammonia that has not been oxidized in the activated sludge tank 5. It is also designed to perform a buffering function to cope with the impact load of influent sewage.

The workpiece through the contact aeration tank 6 finally enters the final settling tank 7. The treated materials introduced into the final settling tank (7) are separated into the solids and the liquid phase by gravity, and the solids are transferred to the first anoxic tank (3) and the microorganism activator (8) through the conveying lines (9 and 10), respectively. Conveyed, and the liquid phase is finally discharged.

<Example>

The sewage treatment apparatus of FIG. 1 was produced on a laboratory scale. Each reactor was made of transparent acrylic with visible inside, and the sewage flowing into the sewage treatment plant was directly collected and used for the experiment. Table 1 shows the reaction tank specifications of the sewage treatment apparatus used in this experiment.

Reactor Standard (Retention time) Remarks Primary Sedimentation Tank and Flow Adjustment Tank 15L (HRT = 12hr) Cylindrical First anaerobic tank 0.63L (HRT = 0.5hr) Cylindrical (sewage sludge planting) Second anaerobic tank 1.88L (HRT = 1.5hr) Cylindrical (sewage sludge planting) Activated sludge tank 3.00L (HRT = 2.4hr) Rectangle (sewage sludge planting) Contact aeration tank 1.50L (HRT = 1.2hr) Rectangle (sewage sludge planting) Final sedimentation tank 4.00L (HRT = 3.4hr) Cylindrical (hopper angle 60 °) Microbial activator 0.50L Cylindrical (sewage sludge planting)

Sample amount used in the experiment was 30L per day, the influent was supplied using a metering pump and a timer to ensure accuracy. The transport of the treated materials in each reactor was installed as natural oil using potential energy, and the sludge was returned to the correct amount using a metering pump and a timer.

Experiment result BOD T-N T-P Concentration (mg / L) Removal rate (%) Concentration (mg / L) Removal rate (%) Concentration (mg / L) Removal rate (%) Influent 99.6 - 33.7 - 3.0 - Runoff 10.9 87.4 14.7 56.4 1.5 49.0

The experimental results summarized in Table 2 are the average concentrations during the operation period and the sewage treatment system with BOD 99.6mg / L, TN 33.7mg / L, and TP 3.0mg / L was treated with this sewage treatment system. BOD 10.9mg / L, TN 14.7mg / L, TP 1.5mg / L, which satisfies 20, 60, 8mg / L of sewage treatment plant effluent standards, showed very good results.

The apparatus and method for removing organic matter and nutrients of sewage according to the present invention can not only stably and reliably remove organic matters in sewage by introducing activated sludge tanks and contact aeration tanks, but also discharge nitrogen and phosphorus as nutrients in sewage treatment plant. It can satisfy the following, and can sufficiently cope with the anticipated regulatory tightening in the future.

1 is a block diagram of an apparatus for treating sewage according to the present invention.

<Explanation of symbols for the main parts of the drawings>

1 .: Sewage treatment device 2 .: Primary settling tank and flow adjusting tank

3 .: first anaerobic tank 4 .: second anaerobic tank

5 .: activated sludge tank 6 .: contact aeration tank

7 .: final sedimentation tank 8 .: microorganism activator

9 ~ 11 .: Sludge conveying line 12 .: Agitator mixer

13 .: blower 14 .: diffuser

15 .: Media

Claims (2)

A primary settling tank and a flow adjusting tank step of equalizing sewage concentration and flow rate and precipitating and removing the sedimentable suspended solids; A first anoxic tank step of denitrifying nitrate nitrogen contained in the sludge returned from the final settling tank by using organic matter in the sewage flowing from the primary settling tank and the flow rate adjusting tank; A second anoxic tank step of denitrifying nitridized nitrite and nitrate nitrogen contained in the sludge introduced from the first anoxic tank and the sludge conveyed from the contact aeration tank using an organic material contained in the sludge; An active sludge tank step of oxidizing the organic matter in the sludge introduced from the second anoxic tank using the aerobic microbial group maintained at a constant concentration in the reactor and nitrifying ammonia nitrogen to nitrite nitrogen and nitrate nitrogen; A contact aeration tank step of extending the microbial retention time using a filter medium and oxidizing untreated organic matter contained in the sludge introduced from the activated sludge tank and oxidizing ammonia nitrogen to nitrite nitrogen and nitrate nitrogen; A final settling tank step of separating the sludge introduced from the contact aeration tank into solids and treated water and finally discharging the sludge; And a microbial activator step of embedding a microbial agent inoculated with soil microorganisms containing Bacillus spp. Microorganisms as inorganic and dominant species and activating the dominant species of the sludge returned from the final sedimentation tank and supplying activated sludge to the activated sludge tank. Way. A primary settling tank and a flow rate adjusting tank (2) for equalizing the concentration and flow rate of the sewage and precipitating and removing the sedimentable suspended solids in the sewage; A first anoxic tank (3) for denitrifying nitrate nitrogen contained in sludge returned from the final settling tank with nitrogen gas using organic matter in the sewage flowing from the primary settling tank and the flow rate adjusting tank; A second anoxic tank (4) for denitrifying nitrous acid and nitrate nitrogen contained in the sludge flowing from the first anoxic tank and the sludge conveyed from the contact aeration tank by using an organic material contained in the sludge; Activated sludge tank which decomposes and removes organic matter in sludge introduced from the second anoxic tank using aerobic microorganisms maintained at a constant concentration in the reactor, decomposes organic nitrogen into ammonia nitrogen and nitrifies ammonia nitrogen into nitrate nitrogen ( 5); A contact aeration tank (6) which extends the microbial residence time as much as possible using the media and secondary oxidation of untreated organic matter contained in the sludge flowing from the activated sludge tank and oxidizing ammonia nitrogen to nitrite nitrogen and nitrate nitrogen; A final settling tank 7 which separates sludge introduced from the contact aeration tank into solids and treated water and finally discharges it; And a microorganism activator (8) containing a microbial preparation inoculated with soil microorganisms containing Bacillus species microorganisms as minerals and dominant species and activating the dominant species of sludge returned from the final settling tank and supplying activated sludge to the activated sludge tank. A return line 9 for returning the sludge separated into solid-liquid separated liquid from the final settling tank 7 to the first anoxic tank 3, and a return line for returning the sludge separated into solid-liquid separated liquid from the final settling tank 7 to the microorganism activating tank 8 ( 10) and a sewage treatment apparatus including a conveying line (11) for conveying sludge separated from the contact aeration tank (6) into a second anoxic tank (4).