JPH07328691A - Nitrification reaction accelerating method utilizing sedimentation tank sludge of sewage treating equipment by immersed filter bed method - Google Patents

Abstract

PURPOSE:To increase the efficiency of nitrogen removal in an immersed filter bed method as one of a sewage treating methods. CONSTITUTION:In order to utilize the nitrification activity of a sedimentation tank sludge of a sewage treating equipment by the immersed filter bed method as one of biological membrane methods, the nitrification activity in a contact aeration tank is accelerated by returning the sedimentation tank sludge to the contact aeration tank and keeping a sedimentation ratio of an activated sludge in the contact aeration tank at about 20% of the sedimentation ratio at which the nitrification activity is manifested most markedly. A treated water containing nitrogen nitrificated in the contact aeration tank is transferred to a next sedimentation tank to perform solid-liquid separation into its sludge and supernatant liquor, thus the treating function to remove the nitrogen being nitrient salts is increased by returning the supernatant liquor containing the nitrificated nitrogen to an anaerobic filter bed tank which denitration reaction progresses.

Description

Detailed Description of the Invention

[0001]

[Field of Industrial Application] The present invention is a method for promoting nitrification reaction which can be used in a sewage treatment facility that uses a submerged filter method, which is one of the biofilm methods, and that has facilities for advanced nitrogen treatment.

[0002]

2. Description of the Related Art A high-level treatment method for nitrogen removal using a dipping filter method is to denitrify nitrated nitrogen by utilizing a nitrification reaction in which ammonia nitrogen is converted to nitrate nitrogen in a contact aeration tank. It is supposed to be returned to the anaerobic filter tank where the reaction progresses for denitrification. However, since the nitrification activity in the contact aeration tank is low and the nitrification reaction is difficult to proceed, the nitrogen removal rate in the anaerobic filter tank is low.

[0003]

DISCLOSURE OF THE INVENTION The present invention aims to solve the problem that the nitrification reaction has been difficult to proceed until now, and to ensure a high degree of nitrogen removal treatment.

[0004]

The method for promoting nitrification of the present invention utilizes the nitrification activity of the sludge in the sedimentation tank, so that the sludge in the sedimentation tank is returned to the contact aeration tank and is sent from the anaerobic filter bed tank. It is characterized in that it is mixed with the sewage containing ammonia nitrogen and is floated to enhance the nitrification reaction in the contact aeration tank.

[0005]

[Function] The contact aeration tank has only a biofilm attached to the filter medium and has a low nitrification activity, so that nitrification of ammonia nitrogen is difficult to proceed. Therefore, originally, paying attention to the nitrifying activity of the sedimentation tank sludge that is transferred to the sludge concentration storage tank, the sedimentation tank sludge is returned to the contact aeration tank and floated to enhance the nitrification activity in the contact aeration tank. As a result, the nitrification reaction can be promoted, and the advanced treatment of nitrogen removal can be ensured through the process of returning the nitrated nitrogen in the contact aeration tank to the anaerobic filter tank.

[0006]

[Example] A route for returning the sludge from the settling tank to the first chamber of the contact aeration tank was set up, and the sedimentation rate of the activated sludge in the contact aeration tank was controlled to about 20% at which the nitrification activity was most expressed. Carried out. The conventional water quality was as follows: Ammonia nitrogen 24 mg / l, Nitrite nitrogen <0, 01 mg / l,
With respect to nitrate nitrogen of 0 and 5 mg / l, the effluent quality of the precipitation tank was ammonia nitrogen of 19 and 5 mg / l, nitrite nitrogen of 0 and 36 mg / l, and nitrate nitrogen of 4 and 3 mg / l. The water quality after installing the equipment of the present invention is as follows: ammonium nitrogen 29, 4 mg / l nitrite nitrogen <0, 01 mg / l, nitrate nitrogen <0, 5 mg /
1, the water quality of the settling tank is ammonia nitrogen.
<0, 1 mg / l, nitrite nitrogen 0, 11 mg / l,
It was confirmed that the nitrate nitrogen was 17, 5 mg / l, and the nitrification reaction proceeded reliably.

[0007]

According to the present invention, the denitrification effect of the immersion filter method, which is one of the methods for treating wastewater, has been limited in the past. However, by systematizing the present invention, floating organisms are suspended. It can be increased to a level comparable to the law, and it can be applied not only to existing sewage treatment plants, but also to new facilities, reducing the load of nutrient salts on public water bodies and contributing greatly to environmental conservation.

[Brief description of drawings]

[Fig. 1] Flow chart of sewage treatment facility treatment using the immersion filter method, which is one of the biofilm methods

Claims (1)

[Claims] 1. A method for enhancing the removal of nitrogen in an anaerobic filter bed tank by utilizing the nitrification activity of a settling tank sludge to promote the nitrification reaction in the contact aeration tank.