JPS63278599A - Sewage purifying device - Google Patents

Abstract

PURPOSE:To improve the denitrification efficiency and the quality of treated water by mixing the water flowing out from a settling and separating chamber or raw water with the circulating water from a circulating chamber at the terminal end of the circulating chamber provided between a contact aeration chamber and an anaerobic filtration chamber. CONSTITUTION:The settling and separating chamber 2 and/or the anaerobic filtration chamber 3, the contact aeration chamber 5, a settling chamber 7, and a sterilizing chamber 9 are arranged in this order, and the circulating chamber 23 is provided between the contact aeration chamber 5 and the anaerobic filtration chamber 3. The water flowing out from the settling and separating chamber 2 or raw water is mixed with the circulating water from the circulating chamber 23 at the terminal end of the chamber 23. As a result, a decrease in the amt. of org. matter necessary for the DO consumption in the denitrification reaction in the anaerobic filtration chamber 3 can be prevented, the denitrification efficiency is improved, the amt. of the org. matter to be used for the denitrification reaction is increased, and the quality of treated water is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for treating sewage such as flush toilet sewage which has a high organic matter concentration and contains nitrogen.

[Conventional technology]

Conventionally, the activated sludge method has been mainly used as a method for treating organic wastewater such as sewage and human waste, but this activated sludge method requires advanced techniques such as adjusting the sludge concentration, air volume, and return sludge volume. Requires maintenance and management skills.

Recently, the biofilm method for treating organic wastewater by immobilizing microorganisms has become popular. Among the biofilm methods, catalytic aeration is the mainstream treatment method at the septic tank level because of its ease of maintenance and management. A feature of this method is that it is possible to grow even organisms with low specific growth rates (typical species include nitrifying bacteria such as nitrite bacteria and nitrate bacteria) that cannot survive in the activated sludge method due to the extremely long sludge volume. Therefore, when wastewater containing relatively high nitrogen content, such as human waste, is treated using this method, the treated water contains a large amount of nitrite nitrogen (Now N) and nitrate nitrogen (NOi N). will remain. In particular, nitrite nitrogen has a chemical oxygen demand (C
In addition to the detected OD) of 1.14 ■/, it is also a well-known fact that when measuring biochemical oxygen demand ffl (BOD), the nitrification reaction in the 7-run bottle causes abnormalities in the BOD value. It is.

In view of the above points and the prevention of environmental pollution, in recent years there has been a particular demand for the removal of nitrogen from wastewater.

Among nitrogen removal technologies, the ammonia stripping method involves injection of an alkaline agent, which makes it difficult to employ at the septic tank level. On the other hand, although the conventional biological denitrification method requires more processing steps, it is advantageous in terms of equipment costs and maintenance costs unless complete denitrification is desired. In particular, Luzack-EtLinger uses organic matter in raw water as a hydrogen donor.
Process (1962) is a superior method compared to other methods.

[Problem that the invention attempts to solve]

However, since it is basically a floating sludge method,
It is impossible to directly introduce it into a contact aeration system. In particular, the organic matter in the raw water is consumed by the dissolved oxygen (Do) brought into the contact aeration chamber when returning the nitrified solution, resulting in a lack of organic matter as the hydrogen donor required for denitrification, resulting in a decrease in the denitrification rate. There is.

The present invention provides a circulation chamber for consuming dissolved oxygen present in the nitrification solution in the factory that circulates the nitrification solution in the catalytic aeration chamber to the anaerobic filtration chamber, thereby effectively providing hydrogen to the organic matter in the raw water. The purpose of the present invention is to provide a sewage purification device equipped with a denitrification mechanism that can be used as a body.

[Means for solving problems]

The structure of the present invention for achieving the above object will be explained using FIGS. 1 to 4 corresponding to the embodiment. When returning the item,
A baffle is installed in the circulation chamber to generate a water flow that does not cause sludge to accumulate, and the aeration liquid passes through the downward flow chamber and upward flow chamber divided by the buckle, thereby reducing Do. It is meant to be consumed.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 4.

2 is provided with an inflow pipe 1 for B water on one side, and an advection port 15 to the anaerobic filtration chamber 3 is provided in the upper part on the other side.
The former 11o4 is a precipitation separation in which an advection baffle 14 is formed. 4 is an advection pipe for causing the filtered wastewater in the anaerobic filtration chamber 3 to flow into the contact aeration chamber 5. Reference numeral 6 denotes an aeration pipe provided at the bottom of the contact aeration chamber 5, and 11 denotes a circulation device having an outlet above for returning the waste water in the contact aeration chamber 5. 7 is a precipitation chamber having a disinfection chamber 9 communicated with the contact aeration chamber 5 at the bottom. Reference numeral 23 denotes a circulation chamber that is connected to the circulation device 11 provided in the contact aeration chamber 5 and has an outlet between the advection baffle near the advection port 15 of the sedimentation separation chamber 2 and the partition plate 13; In the chamber 23, a downward flow chamber 1 is formed by a baffle 12 extending from above the liquid level to near the bottom.
6 and an upward flow chamber 17, which are communicated with each other at the bottom.

Next, to explain the flow of wastewater, the wastewater flowing in from the inflow pipe 1 has impurities removed in the sedimentation separation chamber 2, passes through the advection baffle 14, and is guided to the anaerobic filtration chamber 3 through the advection port 15. In the anaerobic filtration chamber 3, due to the anaerobic bacteria captured and held in the single material filled inside,
In addition to being subjected to anaerobic digestion, nitrite nitrogen (NOi N) and nitrate nitrogen (NOi N) generated in the downstream contact aeration chamber 5 are circulated to the anaerobic filtration chamber 3. Denitrification reaction using arousal substances in the nitrogen as hydrogen donors, NOiN, NOiN, nitrogen scum (
Nz). The reaction formula for these is as follows.

2 NOi + 3 (Hz) → N2↑+2 Hz
O+ 20H-2NOi + 5 (H2,)→N
2↑+4HzO+20H-Through these reactions, theoretically 1.71 edge for NOj N IKy, NOi
For NIKg, 2.86 first BODs are consumed, thereby improving the processing performance of the system as a whole. Furthermore, since half of the alkalinity consumed in the contact aeration chamber 5 is recovered, a decrease in the hydrogen ion concentration (pH) of the treated water can be prevented.

BOD is removed from the wastewater that has flowed into the contact aeration chamber 5 through the advection pipe 4 by the action of the air discharged from the aeration pipe 6 and the aerobic biofilm attached to the surface of the contact material provided inside. . In addition, most of the nitrogen in wastewater, ammonia nitrogen (NH"4 N), is biologically oxidized by the following reaction.

NH2+ 1.5 Ch °Tategi 11 mountain NOi+2H”
NOi + 0.502 rising 31 and 2 NOi In these reactions, 4.6 rim of oxygen and 7.14~ of alkali IJ Ji are consumed for NH2N th.

Next, we will discuss how to circulate the nitrifying solution containing NOi and NOx to the anaerobic filtration chamber 3 mentioned above. It is sufficient to use it.

This nitrifying solution contains oxygen supplied in the contact aeration chamber 5,
It is inevitable that it will be introduced in the form of dissolved oxygen (DO). In general, when the organic substance required for denitrification reaction is expressed in terms of methanol, it is as shown in the following formula.

Mell/-requirement = 2.47 x NOs +
1.53 The BOD/N ratio to obtain a good denitrification rate is said to be 4 or more, and Do consumption is a major problem in wastewater with a low BOD/N ratio (2nd or 7th) such as from frozen fields. In the present invention, as shown in FIG.
The nitrified solution circulation chamber is divided into two chambers by a baffle 12, and when passing through the downward flow chamber 16 and the upward flow chamber 17, DO is consumed by microbial respiration. Downward flow chamber 1
6 and the upward flow chamber 17, as shown in FIG. 3, by making the downward flow chamber 16 narrower and the upward flow chamber 17 wider, unnecessary accumulation of sludge can be prevented. Further, as shown in FIG. 4, if the lower end of the baffle 12 is inclined so as to form a hopper on the upward flow chamber 17 side, the effect will be increased due to the sludge blanket formed in a part of the hopper. In this way DO
The consumed nitrification liquid is transferred to the advection baffle 14 of the precipitation separation chamber 2.
It is mixed with precipitated and separated water near the top of the anaerobic filtration chamber 3.

The wastewater that has been biologically treated through the above process is sent to the sedimentation chamber 7.
After the peeled sludge is sedimented and separated in the sludge, it is brought into contact with a disinfectant 8, stabilized in a disinfection chamber 9, and then discharged from an outflow pipe IO.

[Effects of the Invention] The present invention arranges a precipitation separation chamber and/or an anaerobic filtration chamber, a contact aeration chamber, a sedimentation chamber, and a disinfection chamber in this order, and creates a gap between the contact aeration chamber and the anaerobic filtration chamber. A circulation chamber is provided in the chamber, and the circulating water from the circulation chamber is mixed with the outflow water or raw water from the precipitation separation chamber at the end of the chamber, so that the following effects can be achieved.

1.) Decrease in the amount of organic matter required for DO oil consumption during the denitrification reaction in the anaerobic 1-pass chamber is prevented, the denitrification rate is improved, and the amount of organic matter used for the denitrification reaction is increased, improving the quality of treated water.

2.) By improving the denitrification reaction, the alkalinity can be recovered and a decrease in the pH of the treated water can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a sewage purification device showing an embodiment of the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG. 3 is an enlarged cross-sectional view taken along line B-B in FIG. FIG. 4 is an enlarged cross-sectional view taken along line B-B of another embodiment, and FIG. 5 is an example of a conventional biological denitrification flow sheet. Explanation of symbols

Claims (1)

[Claims] 1. The precipitation separation chamber 2 and/or the anaerobic filtration chamber 3, the contact aeration chamber 5, the precipitation chamber 7, and the disinfection chamber 9 are arranged in this order, and the contact aeration chamber 5 and the anaerobic filtration chamber 5 are arranged in this order. A sewage purification device characterized in that a circulation chamber 23 is provided between the chambers 3, and the circulating water from the circulation chamber 23 is mixed with the outflow water or raw water from the sedimentation separation chamber 2 at the end of the chamber 23. 2. The wastewater according to claim 1, wherein the circulation chamber is formed into a downward flow chamber and an upward flow chamber by a baffle, and the downward flow chamber is formed narrower than the upward flow chamber. Purification device. 3. Claim 1, characterized in that the baffle has a lower end inclined in the shape of a hopper toward the upward flow chamber.
The sewage purification device according to item 1 or 2.