JP4216569B2 - Organic wastewater and sludge treatment method and treatment equipment - Google Patents

Description

【００２２】
【発明の効果】
本発明によれば、有機性廃水処理システムの中で、特に有機物、窒素、リンを含有する有機性廃水及び／又は汚泥、例えば、し尿や浄化槽汚泥の消化脱離液、汚泥の消化液、工場廃水などの高濃度の有機物、窒素及びリンを含有する有機性廃水及び／又は汚泥から、リン酸マグネシウムアンモニウム結晶として窒素及びリンを除去するＭＡＰ処理法において、（１）ＭＡＰ回収率を向上させることができ、（２）ＭＡＰ熟成槽下部から容易に高濃度のＭＡＰ粒子を回収でき、（３）純度の高いＭＡＰを生成することができ、（４）消化槽内のＮＨ_４−Ｎを除去できるため消化槽の阻害がなくなり分解効率が上がり、（５）ＭＡＰ生成を制御できるためＭＡＰ粒子による配管詰まりをなくす事ができる。
【図面の簡単な説明】
【図１】 有機性廃水の処理方法（参考例１）を示す工程図である。
【図２】 本発明の有機性廃水の処理方法（実施例１）を示す工程図である。
【図３】 先に出願の処理方法（特願２００２−１１６２５７）を示す工程図である。
【符号の説明】
１ リン、窒素を含む有機性廃水及び／又は汚泥
２ 消化液
３ 熟成槽処理液
４ 循環液
５ 処理液
６ マグネシウム化合物
７ ｐＨ調整剤
８ 消化槽
９ 熟成槽
１０ ＭＡＰ分離装置
１１ 循環ポンプ
１２ ＭＡＰ結晶取り出し口[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a system for treating organic wastewater and / or sludge in a sewage treatment plant, various wastewater treatment facilities, and the like, and more specifically, digestion and desorption liquid of human waste and septic tank sludge, digestion liquid of sludge, factory wastewater, etc. In a technology for removing phosphorus and the like as magnesium ammonium phosphate (hereinafter referred to as “MAP”) crystals from waste water and sludge containing high concentrations of phosphorus and nitrogen, high-quality MAP having high purity The present invention relates to a method and an apparatus for efficiently recovering crystals.
[0002]
[Prior art]
Conventional general denitrification and dephosphorization simultaneous removal methods include biological treatment methods such as anaerobic anaerobic anaerobic method, anaerobic aerobic method, coagulation precipitation method, alumina adsorption method, etc. There is.
In recent years, MAP treatment and the like have also been attempted for return water, anaerobic digestion and detachment liquid, etc. generated in the process of human waste treatment and sewage treatment. Among these treatment methods, the anaerobic anaerobic and aerobic method has problems such as unstable treatment performance due to changes in water quality and changes in the external environment accompanying seasonal variations. The method combining the anaerobic aerobic method and the coagulation sedimentation method has a problem in that the processing process is complicated and the running cost including chemicals is large. The MAP treatment method is less complicated to operate than the previous two methods, and in particular, it can stably recover phosphorus, and the recovered MAP has an added value as an excellent fertilizer, making effective use of resources. From this point, it can be said that it is an excellent technology.
[0003]
However, even in the case of the MAP method, (b) chemical costs such as sodium hydroxide as a pH adjusting agent and magnesium chloride as an additive are large. (B) MAP is rapidly crystallized in a short time of less than 1 hour. (Hereinafter abbreviated as “rapid MAP reaction”), fine MAP particles are generated, MAP leaks from the reaction tank, and the MAP recovery rate may be reduced to about 60 to 70%. When SS of about 400 mg / liter or more is mixed in the liquid, SS is entangled with the MAP crystal and cannot be recovered as a high-purity MAP crystal. (D) An anaerobic digestion process or the like is adopted before the MAP generation process. In some cases, in the anaerobic digestion process, the MAP reaction that becomes the rate limiting of soluble magnesium in the sludge has already been carried out in the reaction tank, and the generated MAP particles are left as they are in SS. For separation is difficult, there are problems such as have been disposed of with the sludge without being recovered in a mixed state into the digested sludge.
[0004]
Therefore, in order to solve the above-described conventional problems, the present inventors have made it possible to treat wastewater with “organic wastewater and sludge treatment method and treatment apparatus” previously disclosed in the patent application “Japanese Patent Application No. 2002-116257” and the like. Proposed a technique for efficiently recovering phosphorus as MAP.
That is, anaerobic treatment is performed on surplus sludge generated in the organic wastewater treatment process, and a magnesium source is supplied in the process to actively generate MAP in the reaction tank, and the generated MAP is extracted from the digested sludge. An organic wastewater treatment method and treatment device with separation and recovery process was proposed. By implementing this invention, it has become possible to significantly increase the phosphorus recovery rate from wastewater.
[0005]
[Problems to be solved by the invention]
As a result of detailed studies to further improve the above-described invention, the present inventor intends to further improve and stabilize the phosphorus recovery rate as MAP.
The object of the present invention is to further improve the above-described problems of the prior art and the invention of Japanese Patent Application No. 2002-116257. That is, the present invention is an organic wastewater and / or sludge treatment system, particularly wastewater and / or sludge containing organic matter, nitrogen and phosphorus, such as digestion and desorption liquid of human waste and septic tank sludge, and sludge digestion liquid. In the method of adopting anaerobic treatment process for waste water and / or sludge containing high concentration organic matter such as factory waste water, phosphorus and nitrogen, and removing phosphorus as MAP crystals, the phosphorus removal efficiency is greatly improved The problem is to improve.
[0006]
[Means for Solving the Problems]
The present invention has solved the above problems by the following means.
(1) a phosphorus and nitrogen-existing organic wastewater and / or sludge treatment system containing a high concentration of phosphorus and nitrogen incorporating anaerobic digestion process in the anaerobic digestion sludge in the form of magnesium ammonium phosphate A treatment method having a step of taking out of the system, a digestion tank, and a magnesium ammonium phosphate ripening tank which is a fluidized bed system of magnesium ammonium phosphate particles capable of adding and mixing a magnesium source and / or adjusting pH. at least two, and introducing the digested solution containing magnesium ammonium phosphate particles are precipitated in the digested vessel from said digestion tank said aging tank, grown-phosphate magnesium ammonium particles by said aging tank , it was grown magnesium ammonium phosphate particles taken out to the outside from the bottom of the aging tank, and further from the aging tank The crystallization solution is introduced into the magnesium ammonium phosphate particle separator to separate the fine magnesium ammonium phosphate particles and the aging tank treatment liquid, and the separated fine magnesium ammonium phosphate particles are introduced into the aging tank and the separation is performed. A method for treating organic wastewater and / or sludge, wherein a part of the treated ripening tank treatment liquid is discharged out of the system and the rest is circulated to the digestion tank .
[0008]
(2) Form of magnesium ammonium phosphate simultaneously with phosphorus and nitrogen present in anaerobic digestion sludge from organic wastewater and / or sludge treatment equipment containing high concentrations of phosphorus and nitrogen incorporating an anaerobic digestion process in a processing apparatus having a step of taking out of the system, and digestion tank, capable mixing and / or pH adjustment and the addition of magnesium source,-phosphate magnesium ammonium the fluidized bed type of magnesium ammonium phosphate particles has the aging tank at least two, the digestion solution containing magnesium ammonium phosphate particles are precipitated in the digested tank piping and introduced into the aging tank from said digestion tank, a stage after the aging tank It has a magnesium ammonium phosphate particle separator, a pipe for sending the digestive juices to the magnesium ammonium phosphate particle separator from the aging tank, Piping for taking out the magnesium ammonium phosphate particles out of the system from the aging tank, piping for introducing the separated fine magnesium ammonium phosphate particles to the aging tank at the magnesium ammonium phosphate particle separator, the magnesium ammonium phosphate particles Organic wastewater and / or sludge having piping for discharging a part of the ripening tank treatment liquid from the separation apparatus to the outside of the system, and piping for circulating the remaining aging tank treatment liquid to the digestion tank Processing equipment.
(3) The organic waste water and / or sludge treatment apparatus according to (2), wherein the magnesium ammonium phosphate particle separator is a hydrocyclone.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIG.
FIG. 2 is a process diagram showing an embodiment of the present invention, but the content of the present invention is not limited to this.
Organic wastewater and / or sludge 1 containing high-concentration phosphorus and nitrogen is introduced into the digestion tank 8, and organic substances are decomposed by anaerobic digestion, and phosphorus and nitrogen components are eluted as phosphate ions and ammonium ions. .
[0010]
Some phosphate ions and ammonium ions react with magnesium ions contained in the organic waste liquid and / or sludge 1 to generate MAP fine particles. The MAP fine particles generated in the digester 8 gradually grow over a long time, and the MAP particles grown to a sufficient size are precipitated in the digester 8. The precipitated MAP particles are pulled out from the lower part of the digestion tank 8 together with the digestion liquid 2 and are introduced into the aging tank 9 by the pump 11 to become seed crystals of the aging tank 9. Magnesium compound 6 (magnesium chloride, magnesium hydroxide, seawater, etc.) and pH adjuster 7 (sodium hydroxide, potassium hydroxide, calcium hydroxide, sulfuric acid, hydrochloric acid, etc.) are added 9 minutes before the aging tank, and digestive juice 2 At the same time, it is introduced into the aging tank 9 or directly into the aging tank 9.
[0011]
The aging tank 9 may be of any type as long as the MAP particles can easily grow, and a fluidized bed type in which the MAP crystals are held at a high concentration is particularly desirable. Further, the structure of the aging tank 9 may be any structure as long as the MAP particles can grow easily. In particular, the area of the digestive juice 2 introduction portion is narrow and the area is widened on the rear side of the aging tank 9. Things are desirable. When the digestion liquid introduction area of the aging tank 9 is narrow, the flow rate is fast, so that the MAP particles, the magnesium compound, and the pH adjuster 7 are mixed well, and the growth of the MAP particles is promoted. By expanding the area on the rear side of the aging tank 9, the grown MAP particles and the digestive juice 2 are easily separated, and most of the MAP particles can be held in the aging tank 9. Further, in order to efficiently grow the MAP particles in the aging tank 9, in addition to stirring by the flow rate, gas stirring in which the gas generated in the digesting tank 8 is introduced into the aging tank 9 or stirring by a stirrer is used in combination. May be. Further, the growth of the MAP particles may be promoted by heating the aging tank 9.
[0012]
The aging tank treatment liquid 3 containing fine MAP particles is separated into the fine MAP particles and the aging tank treatment liquid 3 by the MAP separator 10, and the fine MAP particles are returned to the aging tank 9. A part of the aging tank treatment liquid 3 that has passed through the MAP separator 10 is discharged out of the system as the treatment liquid 5 and circulated as a circulation liquid 4 to the digestion tank 8. Since a part of the ammonium ion that inhibits the reaction in the digestion tank 8 is removed together with the phosphate ions in the circulating fluid, the decomposition rate in the digestion tank 8 is improved.
[0013]
The MAP separation device 10 installed in the rear stage of the aging tank 9 may be any device as long as the MAP can be efficiently recovered, and a liquid cyclone, a vibration sieve, a centrifugal separator or the like is particularly desirable. The MAP separation apparatus 10 is installed for the purpose of collecting fine MAP particles, but (a) MAP generation in the aging tank 9 is good and almost no fine MAP particles are generated. Therefore, the MAP separation device 10 can be omitted when it is not necessary to collect the fine MAP particles flowing out from the aging tank 9 because it is desired to keep a small amount of MAP particles included.
[0014]
It is desirable that the side surface and the bottom of the digester 8 be smooth and have a certain slope or more so that the precipitated MAP particles in the digester 8 can be quickly recovered, and the slope is desirably 45 degrees or more. Further, it may be made more efficient by attaching a scraper for collecting MAP. It is desirable that the extraction part at the lower part of the digestion tank has an extraction speed of 0.2 m / s or more so that the MAP is not clogged.
[0015]
A MAP crystal take-out port 12 is provided at the bottom of the aging tank 9 so that high-concentration MAP particles can be recovered. The frequency of the MAP recovery may be set when the aging tank 9 is measured with a gravimetric meter and becomes a certain weight or more, or when the interface of the MAP particles is measured with an interface meter and becomes a certain interface or more. desirable.
[0016]
In the present invention, by actively controlling the generation of MAP, the generation of MAP in the pipe can be suppressed, the clogging of the pipe due to MAP can be prevented, and MAP which is an effective resource can be recovered and used.
[0017]
【Example】
Hereinafter, the present invention will be described in more detail by way of an example of the operation result of an experimental plant that actually incorporates a processing technique, but the scope of the present invention is not limited to the examples.
[0018]
Reference example 1
It was set as the structure (digestion tank + aging tank) shown in FIG. 1, and it was made to place an aging tank in the back | latter stage of a digestion tank. Sludge with TS of 40,000 mg / liter and TP of 880 mg / liter was charged into the digester. The treatment time in the digestion tank was 25 days, and the digestion liquid containing MAP particles was taken out from the digestion tank at a rate of 1.5 times the amount of sludge charged to the digestion tank per day and introduced into the aging tank. The treatment time in the aging tank was 12 hours. The treatment liquid PO ₄ -P was 15 mg / liter, the MAP average particle size obtained in the aging tank was 1.70 mm, the MAP purity was 97%, and the phosphorus recovery rate in the waste liquid was improved to 58%.
[0019]
Example 1
The same sludge as in Reference Example 1 is introduced by adopting the structure of the present invention (digestion tank + aging tank + MAP separation apparatus) shown in FIG. 2, placing the aging tank behind the digestion tank, and further providing a MAP separation apparatus. Was processed. The treatment liquid PO ₄ -P was 14 mg / liter, the MAP average particle diameter was 1.65 mm, the MAP purity was 97%, and the phosphorus recovery rate in the waste liquid was improved to 60%.
[0020]
Comparative Example 1
The structure of (digestion tank + MAP separator (prior art Japanese Patent Application No. 2002-116257 (Japanese Patent Laid-Open No. 2004-941) )) shown in FIG. 3 is used, and the same sludge as in Example 1 is added to the digestion tank, and magnesium is added directly. Then, the MAP separation device was processed so as to collect the MAP particles. In this case, PO ₄ -P of the treatment liquid was 21 mg / liter, the MAP average particle diameter was 0.65 mm, the MAP purity was 96%, and the phosphorus recovery rate in the waste liquid was 49%.
The results of Example 1, Reference Example 1 and Comparative Example 1 are shown in Table 1 below.
[0021]
[Table 1]

[0022]
【The invention's effect】
According to the present invention, among organic wastewater treatment systems, in particular, organic wastewater and / or sludge containing organic matter, nitrogen, phosphorus, for example, digestion and desorption liquid of human waste and septic tank sludge, sludge digestion liquid, factory In the MAP treatment method that removes nitrogen and phosphorus as magnesium ammonium phosphate crystals from organic wastewater and / or sludge containing high concentration organic matter such as wastewater, nitrogen and phosphorus, (1) To improve MAP recovery rate wo can, (2) MAP aging tank bottom scolded easy second high concentration Roh MAP particle wo recovery can, (3) purity Roh high MAP wo generated ancient city moth can, (4) anti-mosquito tank inner Roh _NH 4 -N wo removal Therefore, the digestion tank is not obstructed and the decomposition efficiency is increased. (5) Since the MAP production can be controlled, it is possible to eliminate the clogging of piping due to the MAP particles.
[Brief description of the drawings]
FIG. 1 is a process diagram showing a method for treating organic wastewater ( Reference Example 1 ).
FIG. 2 is a process diagram showing a method for treating organic wastewater according to the present invention ( Example 1 ).
FIG. 3 is a process diagram showing a processing method (Japanese Patent Application No. 2002-116257) for an earlier application;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Organic waste water and / or sludge containing phosphorus, 2 Digestion liquid 3 Aging tank processing liquid 4 Circulating liquid 5 Processing liquid 6 Magnesium compound 7 pH adjuster 8 Digestion tank 9 Aging tank 10 MAP separation apparatus 11 Circulation pump 12 MAP crystal Outlet

Claims (3)

From the system in the form of magnesium ammonium phosphate and phosphorous and nitrogen present in the anaerobic digestion process sludge from organic waste and / or sludge treatment system containing a high concentration of phosphorus and nitrogen incorporating anaerobic digestion treatment step A processing method having a step of taking out, at least two of a digestion tank and a magnesium ammonium phosphate ripening tank which is a fluidized bed system of magnesium ammonium phosphate particles capable of adding and mixing magnesium source and / or adjusting pH have introduced a digestive solution containing magnesium ammonium phosphate particles are precipitated in the digested vessel from said digestion tank said aging tank, grown-phosphate magnesium ammonium particles the aging tank, grown Taking out the magnesium ammonium phosphate particles out of the system from the lower part of the aging tank, and further digesting liquid from the aging tank Introduced into the magnesium ammonium phosphate particle separator to separate the fine magnesium ammonium phosphate particles and the aging tank treatment liquid, the separated fine magnesium ammonium phosphate particles were introduced into the aging tank, and the separated ripening A method for treating organic wastewater and / or sludge, wherein a part of the tank treatment liquid is discharged out of the system and the rest is circulated to the digestion tank . Organic wastewater containing high concentrations of phosphorus and nitrogen and / or sludge treatment equipment incorporating an anaerobic digestion treatment process. The phosphorus and nitrogen present in anaerobic digestion sludge are simultaneously removed in the form of magnesium ammonium phosphate. a processing apparatus having a step of removing the by the digestion tank, capable of mixing and / or pH adjustment and the addition of magnesium source,-phosphate magnesium ammonium aging tank of a fluidized bed type of magnesium ammonium phosphate particles at least two, pipes and the magnesium phosphate in stages after the aging tank for introducing digestive juices in the aging tank from said digestion tank containing magnesium ammonium phosphate particles are precipitated in the said digestion vessel having ammonium particle separator, a pipe for sending the digestive juices to the magnesium ammonium phosphate particle separator from the aging tank, the aging From the piping for taking out the magnesium ammonium phosphate particles from the system, the piping for introducing the separated fine magnesium ammonium phosphate particles to the aging tank at the magnesium ammonium phosphate particle separator, the magnesium ammonium phosphate particle separator An organic wastewater and / or sludge treatment apparatus characterized by having a pipe for discharging a part of the aging tank treatment liquid from the system to the outside of the system and a pipe for circulating the remaining aging tank treatment liquid to the digestion tank . The apparatus for treating organic wastewater and / or sludge according to claim 2, wherein the magnesium ammonium phosphate particle separator is a hydrocyclone.

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