JPS5845919B2 - Water treatment method for denitrification - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for removing ammonia nitrogen contained in water to be treated, such as raw human urine or sewage mixed with human waste, by the action of activated sludge, and the treatment tank can be configured compactly. At the same time, the nitrogen removal ability can be improved, and in addition, it is possible to eliminate the need for dilution water and additive chemicals, or to reduce the amount of dilution water and additives, and furthermore, to eliminate the need for circulating treated water between treatment tanks. The purpose is to do.

Next, embodiments of the present invention will be described with reference to illustrative figures.

The raw human waste from the storage tank 1 is supplied to the reaction tank 3 after removing impurities in the pre-treatment device 2. At the same time, raw urine is blown into the pump channel 5 at a rate of lOm to 100
rr1. By circulating the flow through a relatively deep downward flow path 3a and an upward flow path 3b connected thereto, the biochemical oxygen demand is reduced by the action of aerobic activated sludge, and the ammonia nitrogen content is oxidized. Nitrite and nitric acid produced during treatment are removed as nitrogen gas by the action of anaerobic activated sludge.

As mentioned above, in order for the ammonia nitrogen content to be oxidized and then reduced, and for the oxidation and reduction to be performed simultaneously, a button is pressed on the reaction tank 3 to detect the amount of dissolved oxygen. The value is below ippm and the redox potential is 1
It is desirable to manually or automatically adjust the amount of gas supplied from the air supply path 4 using the control valve 4a so that the voltage is 50 mV or less.

The treated water from the reaction tank 3 is supplied to the nitrification tank 6, and oxygen-containing gas such as air is blown in through the air supply path 7 to oxidize the residual ammonia nitrogen with aerobic activated sludge. , supplies the water to be treated to the denitrification tank 8.

In the denitrification tank 8, nitrous acid and nitric acid are finally reduced by the action of anaerobic activated sludge to sufficiently remove ammonia nitrogen, and then the water to be treated is transferred to the re-aeration tank 9. supply to.

Oxygen-containing gas such as air is sent to the re-aeration tank 9 through the air supply path 1
The biochemical oxygen demand of the water to be treated is sufficiently reduced by aerobic activated sludge while being blown in by 0, and further,
Activated sludge is separated from the water to be treated from the reaeration tank 9 in a settling tank 11, and the fresh water is subjected to tertiary treatment such as discharge, reuse, or decolorization.

A portion of the highly concentrated separated sludge from the settling tank 11 is sent to the return path 1.
2 to the reaction tank 3, and the remainder to the sludge storage tank 13.
Send each to.

The concentration of activated sludge returned to the reaction tank 3 is
The activated sludge concentration is 110,000 from reaeration tank 9 to
It is desirable to adjust the amount to be maintained at pp or more, and in the case of sedimentation-separated sludge, the amount of sludge returned is preferably about 2 to 10 times the amount of water to be treated Q input into the reaction tank 3. .

The water to be treated that is supplied to the reaction tank 3 has a weight ratio of total nitrogen to suspended solids of less than 0.06** and 0.1.
It is desirable that the water to be treated be diluted from the water supply channel 14 to the reaction tank 3 as necessary to ensure that the entire treatment is carried out well. Water is supplied at a rate not more than 5 times that of the water to be treated.

Of course, depending on the properties of the water to be treated, dilution water may not be necessary.If dilution water is required, various types of water can be used as dilution water, such as natural fresh water, seawater, or clean water obtained through water treatment. Water may be supplied to one or more of the reaction tank 3, nitrification tank 6, denitrification tank 8, and reaeration tank 9.

The present invention can treat not only raw human urine but also various types of wastewater containing ammonia nitrogen and organic components, such as sewage mixed with human urine, and the specific configuration of the water treatment equipment to which the present invention is applied can be modified in various ways. It is possible.

For example, instead of the sedimentation tank 11, a centrifugal separator or the like can be used, and these are collectively referred to as the sludge separation device 11.

In addition, a coagulation and sedimentation device is added for the water to be treated from the sludge separation device 11, and the generated coagulation and sedimentation sludge is supplied to any of the reaction tank 3, nitrification tank 6, denitrification tank 8, and reaeration tank 9. It's okay.

Next, an example using the above-mentioned equipment will be described.

The various capacities used are as follows.

Reaction tank 32m3 (depth 10m) Nitrification tank 14□3 Denitrification tank 10m3 Re-aeration tank 7TIL3 Sedimentation tank 14m3 The operating conditions of the equipment are as follows.

In summary, in the denitrification water treatment method according to the present invention, water to be treated containing ammonia nitrogen is sent together with activated sludge to a reaction tank 3 having a relatively deep downward flow path 3a and an upward flow path 3b connected thereto. While circulating and flowing, the amount of oxygen-containing gas supplied is adjusted so that the ammonia nitrogen content is oxidized and then reduced by the activated sludge, and the water treated in the reaction tank 3 is transferred to the nitrification tank 6 and the denitrification tank. 8. Re-aeration tank 9
and a sludge separator 11 in that order, and the highly concentrated activated sludge from the sludge separator 11 is supplied from the reaction tank 3 to the reaeration tank 9.

That is, since the reaction tank 3 is of a relatively deep circulation type, a large amount of oxygen gas can be dissolved in the water to be treated, and
Since the activated sludge concentration is maintained at a high concentration, for example, 10,000 pP or more, from the reaction tank 3 to the reaeration tank 9, the treatment efficiency for various types can be significantly improved, and the overall tank capacity can be reduced to 1,000 pP compared to, for example, conventional It can be made as small as /3 or /4 compared to the previous model, greatly improving economic efficiency in terms of facilities and site, etc. Moreover, the total nitrogen removal rate is extremely high, for example, 99% or more. Became.

Because high-load denitrification treatment can be performed in the broken reaction tank 3,
The water to be treated can be treated without dilution or with a much smaller dilution ratio than conventional methods, such as less than 5 times dilution, which is not only advantageous in terms of securing water resources, but also eliminates or slightly increases the amount of treatment due to dilution. did it.

Furthermore, the total nitrogen removal rate in the reaction tank 3 is, for example, 90
% or more, the processing load on the denitrification tank 8 is significantly reduced, making it difficult to introduce chemicals such as caustic soda and methanol as a nutrient source for the anaerobic activated sludge in the denitrification tank 8. It is now unnecessary or can be done in extremely small quantities, saving resources and reducing running costs.

Furthermore, in the past, it was generally necessary to return most of the water to be treated in one tank to another tank located upstream, which made the equipment complicated, but with the present invention, it is simple. It is also possible to treat the water by simply flowing the water to be treated from the reaction tank to the sludge separator 11, and the equipment can also be simplified.

BRIEF DESCRIPTION OF THE DRAWINGS The drawing is a flow sheet illustrating an embodiment of the denitrification water treatment method according to the present invention. 3... Reaction tank, 3a... Downflow path, 3
b... Rising channel, 6... Nitrification tank, 8.
... Denitrification tank, 9 ... Reaeration tank, 11 ...
...Sludge separation equipment.

Claims (1)

[Claims] 1. A relatively deep descending channel 3a and an ascending channel 3 connected thereto.
In the reaction tank 3 having b, the water to be treated containing ammonia nitrogen is circulated and flowed together with activated sludge, and the amount of oxygen-containing gas supplied is controlled so that the ammonia nitrogen is oxidized by the activated sludge and then reduced. The water to be treated that has been adjusted and treated in the reaction tank 3 is supplied to a nitrification tank 6, a denitrification tank 8, a reaeration tank 9, and a sludge separation device 11 in that order, and the highly concentrated activated sludge from the sludge separation device 11 is The reaction tank 3
A water treatment method for denitrification characterized by supplying water from the reaeration tank 9 to the reaeration tank 9. 2 Press the button on the reaction tank 3 and check the detected amount of dissolved oxygen (II)
While adjusting the oxygen-containing gas supply amount so that the distance is 13 m or less and the redox potential is 1-50 mV or less,
The water to be treated is prepared so that the weight ratio of total nitrogen to suspended solids is 0.06 to 0.1, and the activated sludge concentration is adjusted to 1000 from the reaction tank 3 to the reaeration tank 9.
2. The method according to claim 1, wherein the method is maintained at 0ppff1 or more.