JP3435545B2 - Method for adjusting nitrogen content in production of dry sludge fertilizer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a dry sludge fertilizer using sludge generated in a human waste treatment facility. Incidentally, the concept of fertilizer here also includes a soil conditioner. BACKGROUND OF THE INVENTION Conventionally, in a human waste treatment facility, disposal of solids generated during water treatment is performed after separating into solid waste and sludge.
The residue is directly incinerated, while the sludge is dehydrated, dried and incinerated.
A method of landfilling or melting the incineration ash and sludge incineration ash generated at this time is adopted. However, in recent years, it has been difficult to secure landfill sites, and furthermore, there is a problem in that melting treatment is costly due to the large size of the processing apparatus. Therefore, effective utilization of sludge is desired. [0003] From these backgrounds, attention has been paid to the fact that sludge contains nitrogen, phosphoric acid, and potassium, which are fertilizer elements, and attempts have been made to dry dehydrated sludge and use the dried sludge as fertilizer. However, in the current method of simply drying dewatered sludge and using this dried sludge as fertilizer, the nitrogen content changes due to differences in the method of treating human waste water, and the quality of fertilizer varies. Was difficult to use. [0004] The present invention has been made in view of such a background, and when the manure is dehydrated and dried to produce a fertilizer, the final product is dried. An attempt was made to develop a method for adjusting the nitrogen content in the production of a novel dry sludge fertilizer capable of setting the nitrogen content of a sludge fertilizer to a desired value. [0005] A method for adjusting the nitrogen content in the production of dry sludge fertilizer according to the first invention of the present application is to dehydrate sludge generated in a human waste treatment facility. The dewatered sludge is mixed with either or both of the sludge incineration ash obtained by drying and incinerating the sludge component and the incineration ash obtained by incinerating the residue. In the method of obtaining a dried sludge fertilizer by subjecting the mixture to a drying treatment to obtain a dry sludge fertilizer, the sludge incineration ash and the residue incineration ash do not contain a nitrogen component. At the start of operation, the incineration of dried sludge obtained by drying the dewatered sludge is used, and after the production of dried sludge fertilizer, the incineration of this dried sludge fertilizer is used. Dry As the nitrogen component of the sludge fertilizer becomes a desired value, but made as characterized by adjusting the amount of the dry sludge or the dry sludge fertilizer. And is that trying to achieve the above object I also the above-mentioned means. According to the method of the present invention for controlling the nitrogen content in the production of dried sludge fertilizer, the sludge generated in a human waste treatment facility or dewatered sludge obtained by dewatering sludge and incineration of sludge are considered. Since the treated sludge incineration ash and the incineration ash of the residue are mixed and effectively used as dry sludge fertilizer, the amount of incineration is reduced and the amount of landfill and melting is also reduced. Also provided by the present invention
Adjusted dried sludge fertilizer nitrogen content to be produced, the dehydrated sludge dehydrated sludge or sludge, a sludge incineration ash that incineration of sludge, to the then residue was incinerated and residue ash is mixed that reason, by changing the mixing ratio, a dry sludge fertilizer desired nitrogen content. Hereinafter, a method for adjusting a nitrogen content in the production of a dry sludge fertilizer according to the present invention will be specifically described with reference to the drawings. In this explanation, the method of adjusting the nitrogen content in the production of dry sludge fertilizer is first explained,
While describing the method, a dry sludge fertilizer with a controlled nitrogen content will also be described. FIG. 1 is a block diagram showing a system for producing a dried sludge fertilizer, which comprises a drying step A, a distribution step B, an incineration step C, and a mixing step D. The purpose of this embodiment is to obtain a dry sludge fertilizer 9 having a nitrogen content of 5.0% in components other than water. First, the residue 2 and the dewatered sludge 5 (dewatered cake) which are the raw materials of the dried sludge fertilizer 9 will be described. In the night soil treatment facility, the collected manure 1 is removed from the manure 2 and sludge 4 is generated as a result of the water treatment. Then, the sludge 4 is dewatered by a dehydrator to produce dewatered sludge 5. The dewatered sludge 5 in this example is composed of a water content of 80% by weight and a solid content of 20%, and nitrogen N is 6.5% of the solid content. The residue 2 is composed of 60% water and 40% solids by weight, and contains a small amount of nitrogen (N). Next, the drying step A will be described. The drying step A is a step for further removing water contained in the dewatered sludge 5 at the time of starting, and is a step of performing a drying treatment to generate a dried sludge 6. . The dried sludge 6 in this embodiment is composed of 10% moisture and 90% solids by weight, and nitrogen N is 6.5% solids like the dewatered sludge 5.
In addition, during the steady operation, the water contained in the mixture 8 is removed, and the dried sludge fertilizer 9 is generated. The dried sludge fertilizer 9 in this embodiment is composed of 10% water and 90% solids by weight, and nitrogen N is 5.0% solids. Next, the distribution step B will be described. The distribution step B is performed at the start of operation so that the dry sludge fertilizer 9 as the final product has a desired nitrogen content of 5.0%. This is a step of distributing the dried sludge 6 as a product at an appropriate ratio and sending it to the subsequent incineration step C. On the other hand, during steady operation, the dried sludge fertilizer 9 as the product of the drying step A is distributed at an appropriate ratio. This is a process of sending to the subsequent incineration process C. Next, the incineration step C will be described. The incineration step C is a step of incinerating the dried sludge 6 or the dried sludge fertilizer 9 and the residue 2 which are the products of the drying step A. This is a step of generating incineration ash 10 composed of waste incineration ash 3. . The incineration ash 3 in this embodiment does not contain nitrogen N. Also, 30% by weight of the solid content of the dried sludge 6 becomes the sludge incineration ash 7, and 7.8% by weight of the solid content of the residue 2 becomes the incineration ash 3. Next, the mixing step D will be described. This mixing step D includes the incineration ash 10 which is a product of the incineration step C,
This is a step of mixing the dewatered sludge 5 and a step of producing a mixture 8. In this embodiment, the ratio of nitrogen in the components (solid content and incinerated ash 10) of the mixture 8 excluding water is 5.0%. [0014] The production system for carrying out the method for adjusting the nitrogen content in the production of dry sludge fertilizer of the present invention to obtain a dry sludge fertilizer with an adjusted nitrogen content has the specific configuration as described above. The dried sludge fertilizer 9 is generated as follows. In this embodiment, 180 kg / hour (108 kg of water, 72 kg of solid content of nitrogen N trace) of the residue 2 is carried into the manufacturing system, while 500 kg / hour of the dewatered sludge 5 (400 kg of water). , Solid content 1
It is assumed that nitrogen (6.5 kg of nitrogen) is carried in. First, at the start of operation, the dewatered sludge 5
Is processed according to the flow indicated by the broken line in FIG. That is, the dewatered sludge 5 is subjected to a drying treatment in the drying step A to produce the dried sludge 6, and its components have a total weight of 1%.
11.1 kg, moisture 11.1 kg, nitrogen content 6.5 kg out of 100 kg solid content. Then, the dried sludge 6 is distributed in the distribution step B.
In the incineration ash 3 generated after the treatment in the incineration process C
And the sludge incineration ash 7 together with the total weight of the incineration ash 10 is 3
76% (total weight 84.4kg, moisture 8.4kg, solids 76.0kg) is distributed to be carried to incineration process C so that it becomes 0 kg, and the remaining 24% is distributed to be disposed of. Is done. In the incineration step C, the incineration treatment is performed on the dried sludge 6 and the ash 2, and an incineration ash 10 composed of the ash 7 and the ash 3 is generated. Here, 10% by weight of the solid content of the residue 2 becomes the residue incineration ash 3. In this embodiment, the residue incineration ash 3 has a total weight of 7.2 kg (7.2 kg of solid content). Become. Dry sludge 6
The sludge incineration ash 7 has a solid content of 30% by weight, and the sludge incineration ash 7 in this embodiment has a total weight of 22.8 kg.
(22.8 kg solids). By the way, nitrogen N is not contained in the incineration ash 3 and the incineration ash 7 of sludge. Next, incineration ash 10 as a product of the incineration process C
Is carried into the mixing step D, where the dewatered sludge 5 and the incinerated ash 10 are mixed to form a mixture 8, and the components of the mixture 8 are 530 kg in total weight, 400 kg in moisture, and 100 kg in solid content. 0.5 kg, ash content 30 kg. At this point, the ratio of nitrogen N in the components excluding water becomes 5.0%. Next, the mixture 8 is carried into a drying step A, where it is subjected to a drying treatment to become a dried sludge fertilizer 9 as a final product, and its components have a total weight of 144.4 k.
g, moisture 14.4kg, solid content 100kg, nitrogen N6.5k
g, ash content 30 kg. The flow up to the point described above is a flow peculiar to the start of operation. Thereafter, during a steady operation, processing is performed according to the flow indicated by the solid line in FIG. That is, the dried sludge fertilizer 9
The ratio of nitrogen N in the components excluding water should be 5.0%, but the product of the drying step A is dry sludge 6 at the time of start-up, whereas the product of the drying step A is dry at the time of steady operation. It is sludge fertilizer 9. That is, the components of the dried sludge 6 and the dried sludge fertilizer 9 are different, and the dried sludge fertilizer 9 contains about 23% of ash (a ratio of the components excluding water), and is therefore distributed. It is necessary to make the distribution ratio in the process B different from that at the time of starting. In this embodiment, since the sludge ash component in the incineration ash 10 becomes 22.8 kg and the solid content in the sludge dry fertilizer 9 becomes 30% ash, the distribution step B is performed. , 38% (total weight 54.9 kg, moisture 5.5 kg, solids content 38.0 kg, ash content 11.4 kg) of the dried sludge fertilizer 9 is sent to the incineration process C, and the remaining 62% (total weight 89.5 kg) , 8.9 kg of water, 62.0 kg of solids, and 18.6 kg of ash). Thereafter, by treating according to the flow indicated by the solid line in FIG. 1, the ratio of nitrogen in the components excluding water is 5.0%, and the dry sludge fertilizer is 5.0% per hour.
kg (moisture 8.9 kg, solids 62.0 kg, ash 18.6 k
g) Can be manufactured. Other Embodiments In the above-described embodiment, only the residue 2 and the dewatered sludge 5 are used as the raw materials of the dry sludge fertilizer 9. For example, in a mixing step D, an appropriate amount of alkali molecules are mixed. Alternatively, a soil conditioner for alkalizing acidified soil can be produced. Further, in the above-described embodiment, the incineration ash 10 was mixed with the dewatered sludge 5, but there is no problem even if the incineration ash 10 is mixed with the sludge 4 before dehydration because the components do not change. The method for adjusting the nitrogen content in the production of dry sludge fertilizer of the present invention is as described above.
This produces the following effects. First, the effect of the present invention will be described with respect to the method of adjusting the nitrogen content in the production of dry sludge fertilizer. The sludge 4 generated in the night soil treatment facility or the dewatered sludge 5 obtained by dewatering the sludge 4, the sludge incineration ash 7 and the residue incineration ash The incineration ash 10 consisting of 3 is mixed in an appropriate ratio and effectively used as the dry sludge fertilizer 9. Therefore, the amount of incineration disposal is reduced. As a result, the fuel cost is reduced and a global warming phenomenon is caused. Emission of CO ₂ is reduced. Further, since a landfill site and a melting facility are not required, the processing cost can be significantly reduced. The drying sludge fertilizer 9 produced according to the present invention, the dewatered sludge 5 was dehydrated sludge 4 or sludge 4, the ash 3 comprising a sludge incineration ash 7 residue ash 3 which is mixed <br By changing the mixing ratio, a dried sludge fertilizer 9 having a desired nitrogen content can be produced. For this reason, a fertilizer suitable for the soil to be used can be supplied without variation in quality.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 was carrying out the production method of drying sludge fertilizer of the present invention
FIG. 1 is a block diagram illustrating a system . [Description of Signs] 1 human waste 2 ash 3 incineration ash 4 sludge 5 dewatered sludge (dewatered cake) 6 dried sludge 7 sludge incineration ash 8 mixture 9 dried sludge fertilizer 10 incineration ash A drying process B distribution process C incineration process D Mixing process

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C05B 1/00-C05G 5/00 B09B 3/00 C02F 11/00-11/20

Claims (1)

(57) [Claims 1] Sludge generated in a night soil treatment facility is subjected to a dehydration treatment to obtain dewatered sludge, and the sludge component is dried, and then incinerated. A method for mixing a sludge incineration ash and one or both of the incineration ash obtained by incineration of the residue to form a mixture, and subjecting the mixture to a drying treatment to obtain a dry sludge fertilizer; The incineration ash and the residue incineration ash do not contain a nitrogen component, and as the sludge incineration ash, at the start of the operation of the production system, the incineration of the dried sludge obtained by drying the dehydrated sludge is used.
After the dried sludge fertilizer is manufactured, the dried sludge fertilizer is incinerated, and the dried sludge or nitrogen is used so that the nitrogen component of the generated dried sludge fertilizer has a desired value. A method for adjusting the nitrogen content in the production of dry sludge fertilizer, comprising adjusting the amount of the dry sludge fertilizer.