JPH07116692A - Treating device for nitrification and denitrification of sewage - Google Patents

Abstract

PURPOSE:To simplify a constitution and to easily perform design and construction in a treating device for nitrification and denitrification which is equipped with an activated sludge type treating device and a sludge separation device by arranging a plurality of treating units in series in which an anaerobic part and a nitrification part are provided through a partition having a communication port in the lower part and constituting the activated sludge type treating device. CONSTITUTION:A treating device for nitrification and denitrification is equipped with an activated sludge type treating device 1 having an anaerobic part D (D1...) and a nitrification part N (N1...) and with a sludge separation device 7 for separating sludge discharged from the device 1. The activated sludge type treating device 1 is constituted by arranging a plurality of treating units in series in which the anaerobic part D and the nitrification part N are provided through a partition (a) having a communication port in the lower end. The each nitrification part N is constituted by equipping a floaling carrier immobilized with nitrification bacteria, a diffusion means 2 for introducing oxygen-containing gas and an outflow port provided with a means 5 for preventing outflow of the carrier. Further the anaerobic part D is provided with means 4-1 to 4-4 for distributing and supplying raw water 4. Separated sludge 10 sent from a sludge separation device 7 is returned to the first anaerobic part D.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for treating nitrification and denitrification of sewage, and more particularly to a biological nitrification and denitrification apparatus for sewage using a carrier in which nitrifying bacteria are immobilized on gel particles.

[0002]

2. Description of the Related Art As a nitrification treatment apparatus using a nitrifying bacterium-immobilized carrier, the technology described in, for example, Japanese Patent Publication No. 46279/1993 is known. This technique comprises a bioreaction tank and a nitrification tank unit having a diffusing device for accommodating a carrier supporting nitrifying bacteria, and the bioreaction tank is provided with one or more nitrification units. It is an apparatus for circulating and circulating the liquid to be treated in a nitrification tank unit.

However, the above device has the following problems. Since the nitrification solution is circulated to the denitrification section by a method of passing the carrier through a screen to prevent the carrier from flowing out, the number of screen passing devices increases and the required screen area increases in proportion thereto. Since a water channel connecting to the treated liquid outflow portion of each nitrification unit must be attached to introduce the liquid into the denitrification portion and the final settling tank, the water channel is long and the structure is complicated. In order to circulate the nitrification liquid to the denitrification section, the air lift effect by the air diffuser provided in the nitrification section is used,
To obtain the required circulation amount, the air diffused amount tends to be excessive.
In addition, since the nitrifying solution must be circulated through the screen, the amount of circulation of the nitrifying solution tends to decrease due to the water flow resistance of the screen.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel nitrification denitrification treatment apparatus for wastewater, which can solve all the problems of the above technology and can efficiently perform nitrification denitrification treatment with a simple apparatus. And

[0005]

In order to solve the above problems, according to the present invention, an activated sludge type treatment apparatus having an anaerobic section and a nitrification section, and a sludge separation apparatus for separating sludge flowing out from the treatment apparatus. In the nitrification / denitrification treatment apparatus for sewage, the activated sludge type treatment apparatus has a plurality of treatment units having an anaerobic section and a nitrification section arranged in series via a partition wall having a conduction port at a lower end thereof, and each of the treatment units. The nitrification part of
A floating carrier on which nitrifying bacteria are immobilized, an air diffuser for introducing an oxygen-containing gas, and an outlet having a means for preventing the carrier from flowing out of the processing unit are provided, and each of the processing units is provided. The anaerobic part has means for distributing and supplying raw water, and the anaerobic part of the first treatment unit has means for returning the separated sludge from the sludge separating device.

In the above processing unit, it is preferable that the last processing unit has an opening below the water surface above the partition wall. The sludge separation device used in the present invention may be a sedimentation tank or a membrane separation device. Various screens and the like can be used as the carrier outflow preventing means. It is necessary to use an air diffuser that does not damage the biological carrier.

In the present invention, since a plurality of treatment units having the above-mentioned anaerobic part and nitrification part may be arranged, for example, a part corresponding to the above-mentioned nitrification part is arranged in the activated sludge tank, or Originally, if it is a vertical circulation type aeration tank, aeration can be stopped every other tank, and a treatment unit can be formed by simply providing a raw water inflow section for each, and an aeration tank of an existing activated sludge facility can be easily used with a nitrification carrier. The biological nitrification and denitrification equipment that was used can be replaced.

[0008]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. Example 1 FIG. 1 is an overall configuration diagram showing a typical example of the wastewater nitrification denitrification treatment apparatus of the present invention.

In FIG. 1, 1 is an activated sludge tank, and D
_{1 to} D ₄ are anaerobic parts, and N _{1 to} N ₄ are nitrification parts. 2 is an air diffuser and 3 is a stirring pump. a and b are partition walls,
4 is an inflow pipe for sewage (raw water) such as sewage, 4-1 to 4-4
Is a pipe for dispensing sewage into each of D _{1 to} D ₄ . Reference numeral 5 denotes a screen, which is housed in N _{1 to} N ₄ and prevents the carrier flowing in suspension from flowing out, and allows floating activated sludge to pass through. Therefore, the carrier remains in the nitrification zone and the subsequent D
It cannot be moved to the tank.

Reference numeral 6 is an outflow portion of the liquid which has undergone the nitrification denitrification reaction, 7 is a sedimentation tank, 8 is clarified treated water, and 9 is sedimentation sludge. In the settling basin 7, floating activated sludge is settled and separated, and the settling sludge 9 is recycled from the return sludge pipe 10 to the D ₁ tank. 12 is a sludge return pump. Further, 11 is a surplus sludge drawing pipe. The principle of operation of the present invention will be described below. The nitrification tanks N _{1 to} N ₄ contain a biological carrier in which nitrifying bacteria are immobilized on a floatable lightweight carrier such as a polyethylene glycol (PEG) gel, polyvinyl alcohol (PVA) gel, or a granular sponge. There is.

Further, suspended microorganisms which are not immobilized on the carrier, that is, activated sludge, are suspended in D _{1 to} D ₄ . The agitation pump 3 enables the floating microorganisms of the activated sludge to efficiently contact the wastewater. Oxygen is given to the nitrification carrier by the oxygen-containing gas supplied from the diffuser 2. In addition, the nitrification carrier is converted into N ₁ by the rising motion of the diffused gas.
~ Suspended in N ₄ tank. Thus, sewage, such as sewage, anaerobic section flows into D, by denitrifying bacteria NO _x -N coming flows from the preceding nitrification unit is suspended form, BO in wastewater
The D component is reduced to N ₂ gas by using it as a hydrogen donor.

The NO _x -N produced in the nitrification section N ₄ flows into the anaerobic section D ₁ together with the returned sludge. Next, in the nitrification section N, NH ₄ − contained in the raw wastewater is
N is NO _x -N by nitrification nitrification carrier (mainly NO
_3- N type). Some floating microorganisms,
Nitrification can proceed. Anaerobic part D following the nitrification part N
The liquid containing NO _x -N and the floating microorganisms flow out to the nitric acid carrier, and the nitrification carrier is prevented from flowing out by the screen 5.

If the screen 5 is not provided, the nitrification carrier in the nitrification sections N _{1 to} N ₄ will move along with the flow of water and will collect in the nitrification section N ₄ . Invite. Then, the outflow slurry from the nitrification section N ₄ is settled and separated in the settling tank 7, and is separated into the clear supernatant water 8 and the settling sludge 9. The anaerobic part D ₄ and the nitrification part N
_It is preferable to provide an opening A below the water surface above the partition wall that divides ₄ so that NO _x -N generated in the nitrification section N ₄ is circulated to the anaerobic section D ₄ and denitrified. It In this case, the nitrification carrier flows into the anaerobic part D ₄ through the opening A, but there is no particular problem.

[0014]

According to the present invention, the following effects can be obtained. Since the device configuration is extremely simple, design and construction is easy. Since it is not necessary to attach a water channel to each of the nitrification units N _{1 to} N ₄ , the structure is simplified. Since it is not necessary to forcibly recycle the liquid in the nitrification section to the anaerobic tank by the air lift, the amount of air supplied to the air diffusers provided in the nitrification sections N _{1 to} N ₄ can be small. The conventional activated sludge type treatment tank can be converted to a nitrification and denitrification device with a simple modification.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an example of a nitrification denitrification treatment apparatus of the present invention.

[Explanation of symbols]

1: Activated sludge tank, 2: Air diffuser, 3: Stirring pump, 4:
Raw water inflow pipe, 4-1 to 4-4: Raw water injection pipe, 5: Screen, 6: Liquid outflow part, 7: Sedimentation tank, 8: Clarified treated water,
9: Settled sludge, 10: Returned sludge, 11: Excess sludge, 1
2: pump, a, b: partition wall, D _{1 to} D ₄ : anaerobic part, N ₁
~ N ₄ : Nitrification part, A: Opening part

Claims (2)

[Claims] 1. A nitrification denitrification treatment apparatus for wastewater comprising an activated sludge type treatment apparatus having an anaerobic section and a nitrification section, and a sludge separation apparatus for separating sludge flowing out from the treatment apparatus,
In the activated sludge type treatment device, a plurality of treatment units having an anaerobic part and a nitrification part are arranged in series via a partition wall having a conduction port at the lower end, and nitrifying bacteria are immobilized in the nitrification part of each treatment unit. The floating carrier, an air diffusing means for introducing an oxygen-containing gas, and an outlet having a means for preventing the carrier from flowing out of the processing unit are provided, and the anaerobic part of each processing unit, An apparatus for nitrifying and denitrifying sludge, comprising means for distributing and supplying raw water, and means for returning the separated sludge from the sludge separating apparatus to the anaerobic part of the first treatment unit. 2. The nitrification denitrification treatment apparatus of sewage according to claim 1, wherein in the last treatment unit, an opening is provided below the upper water surface of the partition wall in the last treatment unit.