JPH06304552A - Removing method of phosphorus and ammonia - Google Patents

Abstract

PURPOSE:To effectively and easily remove phosphorus component and ammonia component in sewage water or river water by allowing an aq. solution containing phosphorus ion and ammonia ion to come into contact with zeolite before allowing it to come into contact with an active alumina. CONSTITUTION:In the case of removing phosphorus component and ammonia component from the solution containing phosphorus and ammonia (aq. solution to be treated), at first, the aq. solution to be treated is brought into contact with zeolite. That is, the aq. solution to be treated is passed through a column or the like, in which zeolite is packed. In this case, the flow rate of the aq. solution and the packing quantity of zeolite are adjusted so that the contact time of the aq. solution to be treated with the zeolite is set for >=10 min, particularly preferably 10-20 min. Next, the aq. solution to be treated, which has been brought into contact with zeolite, is brought into contact with the active alumina. As a result, phosphorus component and ammonia component in the aq. solution to be treated is more efficiently removed than in the case of removing phosphorus component by active alumina only.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphorus and ammonia removing method capable of efficiently removing phosphorus and ammonia components in sewage, river water and the like.

[0002]

2. Description of the Related Art Conventionally, phosphorus and ammonia components contained in sewage, river water, etc. have been known to cause eutrophication and pollution of lakes and marshes, and various methods for removing these components have been developed. Has been done. For example, as a method for removing phosphoric acid, an adsorption method using activated alumina is generally known, and it has been proposed to coexist with calcium ions in order to increase the treatment amount by the activated alumina. On the other hand, as a method for removing ammonia, an ion exchange method using zeolite is generally known.

However, in the method for removing the phosphorus component, the method in which activated alumina and calcium ions coexist can remove the phosphorus component more effectively than the conventional removal method using activated alumina alone. It is necessary to control the processing conditions such as the amount of added ions and pH adjustment, and there is a problem that the method itself becomes complicated. Further, it has been conventionally considered that it is sufficient to remove either the phosphorus component or the ammonia component, and as a method for simultaneously removing the phosphorus component and the ammonia component, the only treatment condition control method is a treatment method using a microorganism. It is the current situation that is only proposed. Therefore, in order to remove the phosphorus component and the ammonia component at the same time, it is conceivable to combine the activated alumina treatment and the zeolite treatment, but it is not possible to effectively remove these components by simply combining them. The actual situation is that the combination of the activated alumina treatment and the zeolite treatment has not been performed.

Further, since activated alumina generally used for phosphorus component removal is expensive, it is desired to develop a technique for extending the period of use of activated alumina without reducing the phosphorus component removal amount.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for removing phosphorus and ammonia which can effectively and easily remove phosphorus components and ammonia components in sewage, river water and the like. .

[0006] Another object of the present invention is to provide a method for removing phosphorus and ammonia which can prolong the period of use of the activated alumina used without reducing the removal amount of phosphorus components.

[0007]

According to the present invention, there is provided a method for removing phosphorus and ammonia, which comprises contacting an aqueous solution containing phosphorus ions and ammonium ions with zeolite and then with activated alumina. It

The present invention will be described in more detail below.

The method for removing phosphorus and ammonia of the present invention is a method in which an aqueous solution containing phosphorus and ammonia such as sewage, river water, industrial wastewater, wastewater in an aeration tank of a sewage treatment plant is brought into contact with zeolite, and then activated alumina is added. It can be carried out by contact.

In the removal method of the present invention, first, an aqueous solution containing phosphorus and ammonia is brought into contact with zeolite.
As the zeolite, a zeolite usually used for removing ammonia, specifically, for example, clinoptilolite-based zeolite, mordenite (morde)
Preferable examples thereof include nite) -based zeolite, and the particle size thereof is preferably 2.3 to 4.6 mm. The aqueous solution containing phosphorus and ammonia can be brought into contact with the zeolite by, for example, packing the zeolite in a column or the like, and passing the aqueous solution containing the phosphorus and ammonia through the column or the like packed with the zeolite. The loading of zeolite varies depending on the amount of ammonia contained, but preferably the inflow rate and the zeolite are such that the contact time between the aqueous solution containing phosphorus and ammonia and the zeolite is 10 minutes or more, particularly 10 to 20 minutes. It is sufficient to adjust the filling amount. If the contact time is less than 10 minutes, the amount of ammonia removed decreases, which is not preferable. Such zeolite treatment preferably has a pH of 7-
It is preferable to carry out under the conditions of 8.5, and by this zeolite treatment, ammonia is first effectively removed, and calcium ion is contained in the treated aqueous solution containing phosphorus and ammonia by the ion exchange action of the zeolite.

Next, in the removal method of the present invention, the zeolite-treated aqueous solution containing phosphorus and ammonia is brought into contact with activated alumina. As the activated alumina, activated alumina or the like usually used for phosphorus removal can be preferably used, and the particle size thereof is preferably 2.0 to 4.0 mm. To bring the aqueous solution containing the zeolite-treated phosphorus and ammonia into contact with activated alumina,
For example, it can be carried out by packing activated alumina in a column or the like, and passing the zeolite-treated aqueous solution containing phosphorus and ammonia through the column or the like. At this time, contact of the zeolite-treated aqueous solution containing phosphorus and ammonia with the activated alumina is performed by disposing a column or the like packed with the activated alumina so that the activated alumina treatment can be continuously performed after the zeolite treatment. Is preferred. The filling amount of the activated alumina varies depending on the amount of phosphorus contained, but preferably the contact time between the aqueous solution containing the zeolite-treated phosphorus and ammonia and the activated alumina is 10 to 30 minutes,
In particular, the inflow rate and the activated alumina filling amount may be adjusted so as to be 10 to 20 minutes. When the contact time is less than 10 minutes, the phosphorus removal amount decreases, and when it exceeds 30 minutes, the phosphorus removal ability cannot be expected to be improved, and the phosphorus removal ability life of the activated alumina decreases. Is not preferred. Such activated alumina treatment is preferably pH
It is preferable to carry out under the conditions of 7 to 8.5.

In the removal method of the present invention, it is necessary to carry out the active alumina treatment after the above zeolite treatment. When the active alumina treatment is performed and then the zeolite treatment is performed, or when the active alumina treatment and the zeolite treatment are simultaneously performed. In addition, the phosphorus removing ability is lowered, and further the phosphorus removing ability life of the activated alumina is shortened.

In the removal method of the present invention, the zeolite and activated alumina used are replaced when the removal amounts of phosphoric acid and ammonium are about 24000 mg / liter or less of phosphoric acid and 6000 mg / liter or less of ammonium, respectively. It does not need any special control.

[0014]

According to the method for removing phosphorus and ammonia of the present invention, phosphorus and ammonia can be effectively removed by a simple method in which an aqueous solution containing phosphorus and ammonia is simply brought into contact with zeolite and activated alumina. And, the contact with the activated alumina, after contacting the zeolite, is contacted with the activated alumina, the phosphorus removal amount is increased without increasing the amount of the activated alumina, as compared with the removal of the phosphorus component by the activated alumina alone, and The life of phosphorus removal ability of activated alumina can be extended.

[0015]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0016]

Example 1 A polypropylene column having an inner diameter of 30 mm was filled with 20 g of activated alumina (manufactured by Catalysts & Chemicals Industry Co., Ltd.) having a particle diameter of 3.0 mm so as to be 25 ml. On the other hand, 18 g of natural zeolite with a particle size of 4.0 mm is applied to the same column.
Was charged to 25 ml. Next, the column packed with zeolite and the column packed with activated alumina were arranged in series, and the sample liquid was passed from the column packed with zeolite at a flow rate of SV = 5 (125 ml / hour).
As a sample solution, potassium dihydrogen phosphate and ammonium chloride were dissolved in tap water to have a phosphoric acid concentration of 5 mg / liter,
An aqueous solution containing 30 mg / liter of ammonia was used. The concentration of phosphoric acid and the concentration of ammonia in the treatment liquid that passed through the column filled with zeolite and the column filled with activated alumina were measured according to the amount of sample liquid passed. The results of changes in phosphoric acid concentration are shown in FIG. 1, and the results of changes in ammonia concentration are shown in FIG.

[0017]

Comparative Example 1 A column filled with activated alumina was prepared in the same manner as in Example 1 except that water was passed through the sample solution not from the side filled with zeolite but from the side filled with activated alumina. The phosphoric acid concentration and the ammonia concentration in the treatment liquid that passed through the column packed with zeolite were measured according to the amount of the sample liquid passed. At this time, the change in ammonia concentration was the same as in Example 1. The results of changes in phosphoric acid concentration are shown in FIG.

[0018]

[Comparative Example 2] The phosphoric acid concentration and the ammonia concentration in the treatment liquid passed through the column filled with activated alumina were the same as in Example 1 except that the sample liquid was passed through only the column filled with activated alumina. The measurement was performed according to the liquid passing amount. At this time, ammonia was not removed. The results of changes in phosphoric acid concentration are shown in FIG.

From the results shown in FIGS. 1 and 2, in the method of the present invention, ammonia is effectively removed, and phosphoric acid is also removed by contacting Comparative Example 2 with activated alumina alone and activated alumina, and then contacting with zeolite. In comparison with Comparative Example 1, the amount can be increased, and Comparative Examples 1 and 2
It is understood that the life of phosphorus removal ability of activated alumina can be extended because the rate of decrease is slower than the reduction of phosphorus removal ability of.

[Brief description of drawings]

FIG. 1 is a graph showing the amount of phosphoric acid removed according to changes in the amount of sample liquid passing through in Examples and Comparative Examples.

FIG. 2 is a graph showing the amount of ammonia removed according to a change in the amount of sample solution passed in Example 1.

Claims (1)

[Claims] 1. A method for removing phosphorus and ammonia, which comprises bringing an aqueous solution containing phosphorus ions and ammonium ions into contact with zeolite and then contacting with activated alumina.