JP7373638B2 - Digested sludge treatment method and wastewater treatment equipment - Google Patents

Description

The present invention relates to a method for treating biomass digested fluid and its wastewater treatment device, and more specifically to a method for treating so-called biomass digested fluid, which is wastewater containing residue left after power generation in a biomass power generation facility. The present invention relates to a processing device for biomass digestive fluid (hereinafter sometimes referred to as "wastewater") for use in a processing method. The present invention provides new technology and new products related to the above-mentioned biomass digestive fluid treatment method and its wastewater treatment device.

Biomass power generation, which is subject to the renewable energy feed-in tariff system (purchase period: 20 years) that began in 2012, is likely to further increase as renewable energy expands. However, similar to nuclear power generation, there is a problem that residue remains after power generation, and wastewater containing this residue is called biomass digestate.

To process this biomass digestive fluid, there are examples of the development of concentration and distillation technology after converting it into a filtrate, but there is no prior solid-liquid separation technology. It is used for restoration, grassland restoration, etc. Here, the reason why solid-liquid separation technology for biomass digestive fluid is not possible is that the digestive fluid emulsifies to form a stable emulsion and is difficult to aggregate, and the solids are not decomposed. The particles become fine and the molecules combine to form micelles, creating a colloidal state, making it difficult to form flocs and dehydrate.

Here, to summarize the processing technologies for biomass digestive juices, conventional technologies include, for example, 1) efficient recycling of food waste discharged from the restaurant industry and food manufacturing plants as feed and fuel; 2) A recycling system that ferments the food waste with methane and uses the digestive fluid and gas (Patent Document 1); 2) anaerobically digests a water-diluted slurry of soy sauce lees to completely remove most of the soy sauce lees; Anaerobic treatment method for complete decomposition (Patent Document 2), 3) Biomass fuel conversion system equipped with a methane fermentation tank for methane fermentation of a solubilized solution of biomass resources and its control method (Patent Document 3), 4) Biomass resources In order to utilize methane with high efficiency, a method has been proposed in which the residue and digestive fluid produced by methane fermentation treatment are hydrothermally treated and recovered (Patent Document 4).

In addition, as other prior art, for example, 5) a method of introducing a digestive fluid containing a residue produced by methane fermentation of organic waste or biomass resources into an incinerator or melting furnace for treatment, and its treatment equipment (patent document 5), 6) Grass-based biomass digestive fluid and grass-based biomass digestion method (Patent Document 6), 7) Digestive fluid processing system that separates and recovers solid components from the digestive fluid generated in a biomass plant in a reusable form (Patent Document 6) Reference 7), etc. have been proposed.

Generally, 8) water-soluble proteins are separated using a method of treatment with iron salts or aluminum salts, which have the effect of flocculating through charge neutralization, and this treatment removes the fine flocs from water. In order to facilitate separation, a synthetic polymer flocculant is used, and in order to separate the flocs thus flocculated into solids, a method using pressure flotation separation has been proposed (Non-Patent Document 1). .

In general, in facilities where conventional seafood processing wastewater is collected and jointly processed, for example, when treating fishery processing wastewater flocs whose composition varies widely, it is not possible to dewater the aggregated flocs using a screw press. Almost impossible. Therefore, the current method of dehydration is to remove water through an evaporation process using a boiler, but this method is expensive, emits a large amount of CO ₂ , and has a very large environmental impact. Therefore, in this technical field, there has been an urgent need to establish a new dehydration system with a low environmental impact to replace the current dehydration system using a boiler evaporation process.

Regarding the purification treatment of biomass power generation digested fluid, the standard activated sludge method, for example, is currently becoming mainstream as a method for purifying the biomass digested fluid to a level where it can be discharged. However, in order to install purification equipment using the activated sludge method, it is necessary to install large-scale purification equipment that includes, for example, a regulating pond, a biological treatment tank (aeration tank), a sedimentation tank, and equipment for operating these. In terms of costs and running costs, it is inefficient and uneconomical for equipment to be installed individually by small and medium-sized businesses. Therefore, there has been a strong demand in this technical field to develop new purification techniques and purification facilities that are smaller in size, more efficient, and more practical.

Japanese Patent Application Publication No. 2003-88838 Japanese Patent Application Publication No. 2005-6649 Japanese Patent Application Publication No. 2007-313427 Japanese Patent Application Publication No. 2008-43902 Japanese Patent Application Publication No. 2008-221105 Japanese Patent Application Publication No. 2012-16652 Japanese Patent Application Publication No. 2016-10742

Edited by the Waste Treatment and Recycling Technology Handbook Editorial Committee, "Waste Treatment and Recycling Technology Handbook", published by Construction Industry Research Group Co., Ltd., November 25, 1993, p. 407 left column lines 9-32

Until now, the present inventors have conducted various studies on the purification treatment of biomass power generation digestive fluid (hereinafter sometimes referred to as "biomass digestive fluid"). Since it is emulsified and forms a stable emulsion state, solid-liquid separation is impossible and removal/dehydration is extremely difficult. It has been found that in many cases, the water is allowed to flow into the aeration tank).

In other words, in the conventionally known existing technology, even if ordinary dehydration aids, flocculants, etc. are added to the contaminated waste liquid containing the digestive juices to generate (form) flocs, the moisture content of the residue cake cannot be reduced. The reality is that it is technically extremely difficult to reduce the temperature to about 70% or less, and it is considered extremely difficult to solve this problem.

Under these circumstances, the present inventors determined the Mp value (Moisture percentage value; A specific dehydration aid having an Mp (cake moisture content) ≦70 (evaluation) is used in combination with a flocculant compatible with the dehydration aid, and at least a mixing tank - a reaction tank - a sludge dehydrator - (neutralization tank) - In a purification facility equipped with a biological treatment tank (aeration tank), the process of adding the above-mentioned specific dehydration aid to the water to be treated in a mixing tank, and then adding a flocculant to the water to be treated in a reaction tank. A step of forming flocs; extra large (φ10 mm or more) to large (φ5 to 10 mm); a highly transparent desorbed liquid from which the flocs are removed in a sludge dehydrator; and a dehydrated cake; water content of 70. % or less, and then the desorbed liquid is introduced into a biological treatment tank (aeration tank) to perform biological treatment, thereby reducing the BOD volume load and the amount of sludge generated. The present inventors have discovered that a stable water treatment effect can be achieved by suppressing the amount of water and reducing the amount of oxygen required, and that biological treatment can be efficiently carried out in a biological treatment tank (aeration tank), leading to the completion of the present invention.

In the present invention, a specific dehydration aid having an Mp value (Moisture percentage value; moisture content evaluation) of "Mp (cake moisture content) ≦70" means that the dehydration aid is added to the biomass digested fluid of the water to be treated. and a flocculant to form flocs; extra large (φ10 mm or more) to large (φ5 to 10 mm); and a dehydrated cake; moisture content of 70% or less. It is defined as a dehydration aid that has the ability to be separated (expected), that is, the ability to dehydrate the cake moisture content from 55% or less to 55 to 70%.

In the present invention, in order to conduct a dehydration test, in a purification facility equipped with at least a mixing tank, a reaction tank, a sludge dehydrator, a neutralization tank, and a biological treatment tank (aeration tank), in the mixing tank and the reaction tank, When various dewatering aids and flocculants were added to the water to be treated and tested, as shown in Table 5 (see paragraph 0067) below, the floc and cake dewatering rates were evaluated. The transparency of the supernatant water is "turbid → transparent" and the size of the flocs formed in the reaction tank is E → A, that is, E: no flocculation, D: small (φ3 mm). Below), C: Medium (φ3-5mm), B: Large (φ5-10mm), A: Extra-large (φ10mm or more), and the predicted (expected) moisture content of the cake generated from the sludge dehydrator. The following results were obtained: E→A, that is, E: 90% or more, D: 80-90%, C: 70-80%, B: 55-70%, and A: 55% or less.

In the present invention, the predicted (expected) cake moisture content of the dehydrated cake is evaluated using the values E to A in the "Evaluation" section of Table 5 (see paragraph 0067) described later as the "Mp value (Moisture percentage value (moisture content evaluation)". In the present invention, regarding the performance of the dehydration aid, for example, when the predicted (expected) cake moisture content is 55% or less in the evaluation of the cake moisture content of the dehydrated cake, this is evaluated as "Mp". (Cake moisture content)≦55”, and when it is 55 to 70%, this will be expressed as “Mp (cake moisture content) = 55 to 70”.

The present invention relates to the formation of flocs of biomass digestive fluid; By removing/dehydrating, the separated solution from which flocs have been removed and the dehydrated cake; water content of 70% or less, more specifically, water content of 55% or less or 55-70%, thereby reducing the BOD volume load. , a method for treating biomass digested fluid that can be expected to have a stable water treatment effect by suppressing the amount of sludge generated and reducing the amount of oxygen required, and that enables biological treatment to be carried out in a biological treatment tank (aeration tank). The purpose is to provide the following.

Furthermore, the present invention forms flocs; extra large (φ10 mm or more) to large (φ5 to 10 mm) in a reaction tank by using the specific dehydration aid and a flocculant compatible with the dehydration aid It also makes it possible to reduce the water content of the dehydrated cake to 70% or less, more specifically, to 55% or less to 55-70%, thereby reducing the water content in the biological treatment tank (aeration tank). The object of the present invention is to provide a method for treating biomass digestive fluid and a wastewater treatment device for the same, which are characterized by making biological treatment possible.

The present invention for solving the above problems is comprised of the following technical means.
(1) A method for processing biomass digestive fluid, comprising:
A dehydration aid having an Mp value (moisture percentage value) of Mp (cake moisture content) ≦55 to Mp (cake moisture content) = 55 to 70 and floc are added to the biomass digested liquid of the water to be treated. A process of adding a flocculant having the ability to form a fluff-like precipitate to form flocs; A biomass digestive liquid characterized by comprising the steps of separating the desorbed liquid into 55% or less to 55-70%, and then introducing the desorbed liquid into a biological treatment tank (aeration tank) to perform biological treatment. processing method.
(2) In a purification facility equipped with at least a mixing tank, a reaction tank, a sludge dehydrator, a (neutralization tank), and a biological treatment tank, the above-mentioned specific dehydration aid is added to the biomass digested liquid of the water to be treated in the mixing tank. Adding process, then in a reaction tank, a flocculant having floc-forming ability is added to the water to be treated to form flocs that include emulsified components and fine particle components in the biomass digestive fluid; extra large (φ10 mm or more) to large (5 to 10 mm in diameter), a step of removing the flocs with a sludge dehydrator and simultaneously separating it into a dehydrated liquid from which the flocs have been removed and a dehydrated cake with a water content of 55% or less to 55 to 70%; The treatment method according to (1) above, further comprising the step of introducing the desorbed liquid into a biological treatment tank (aeration tank) to perform biological treatment.
(3) A dehydration aid having an Mp value (moisture content evaluation) of Mp (cake moisture content) = 55 to 70 and a flocculant having floc formation ability are added to form large flocs (φ5 to 10 mm). A step of separating the desorbed liquid from which flocs have been removed and a dehydrated cake (water content: 55 to 70%). Next, the desorbed liquid is put into a biological treatment tank (aeration tank) for biological treatment. The processing method according to (1) or (2) above, comprising the step of performing.
(4) Any one of (1) to (3) above, wherein before the water to be treated enters the biological treatment tank, an operation is performed to remove flocs containing emulsified components and particulate components in the biomass digestive fluid. Processing method described in .
(5) Any one of (1) to (3) above, where, if necessary, neutralization of the disinfectant is performed in the neutralization tank before the water to be treated enters the biological treatment tank (aeration tank). Processing method described in .
(6) Adding 0.1% or less (based on wastewater volume) of the above-mentioned dehydration aid to the biomass digested liquid of the water to be treated in a mixing tank, according to any one of (1) to (3) above. Processing method described.
(7) The method according to any one of (1) to (3) above, wherein 1% or less (0.2% aqueous solution) of a flocculant is added to the biomass digested liquid of the water to be treated in the reaction tank. Processing method.
(8) A wastewater treatment device for use in the method for treating biomass digestive fluid according to any one of (1) to (7) above,
The components include a purification facility equipped with at least a mixing tank, a reaction tank, a sludge dewatering machine, a neutralization tank, and a biological treatment tank,
1) In a mixing tank, add a dehydration aid having an Mp value (moisture content evaluation) of Mp (cake water content) ≦55 to Mp (cake water content) = 55 to 70 to the biomass digested liquid of the water to be treated. process,
2) In the reaction tank, a flocculant with floc-forming ability is added to the water to be treated to form flocs that include emulsified components and fine particle components in the biomass digestive fluid; a step of forming;
3) Separating into a dehydrated liquid from which the flocs have been removed and a dehydrated cake with a water content of 55% or less to 55-70% using a sludge dehydrator;
The above-mentioned wastewater treatment apparatus is characterized in that the desorbed liquid is introduced into a biological treatment tank (aeration tank) to carry out biological treatment.
(9) 1) Adding a dehydration aid having an Mp value (moisture content evaluation) of Mp (cake water content) = 55 to 70 to the biomass digested liquid of the water to be treated in a mixing tank;
2) A step of adding a flocculant to the water to be treated in a reaction tank to form a large floc (φ5 to 10 mm) containing the emulsified component and particulate component in the biomass digestive fluid;
3) A step of separating into a dehydrated liquid from which the flocs have been removed and a dehydrated cake with a water content of 55 to 70% using a sludge dehydrator;
The wastewater treatment apparatus according to (8) above, wherein the desorbed liquid is introduced into a biological treatment tank (aeration tank) to carry out biological treatment.

Next, the present invention will be explained in more detail.
The biomass digested liquid, which is the object to be treated in the present invention, refers to wastewater generated from the above-mentioned facility, which contains residues remaining after power generation in the biomass power generation facility is completed. Regarding this biomass digested fluid, in this technical field, there are cases where the biomass digested fluid is allowed to flow into the biological treatment tank (aeration tank) untreated. ) did not go well.

In addition, when purifying biomass digestive juices, the digestive juices are emulsified and form a stable emulsion state, which makes coagulation difficult.Also, the solids are decomposed and the particles become fine, and the molecules associate and form micelles. By forming flocs into a colloidal state, it is difficult to form flocs with sizes ranging from extra large (φ10 mm or more) to large (φ5 to 10 mm), especially in the reaction process of a reaction tank, using known existing techniques. In addition, it is quite difficult to separate the dehydrated liquid from the dehydrated cake in the floc removal/dehydration process using a sludge dehydrator, and the desorption process involves removing flocs from extra large (φ10 mm or more) to large (φ5 to 10 mm). It is extremely difficult to separate the liquid from the dehydrated cake; the moisture content is below 70%, that is, between 55% and 55% to 70%.In this technical field, we have developed a method to efficiently purify biomass digested liquid. It was strongly requested to do so.

The present inventors have so far researched and developed various methods for treating floss of fishery processing wastewater and parlor wastewater, and in order to treat biomass digestive liquid generated from biomass power generation facilities, we have developed Focusing on emulsifying components and particulate components, in order to remove them before they flow into the biological treatment tank (aeration tank), we use a specific dehydration aid and a flocculant that is compatible with the dehydration aid. , by forming extra-large (φ10 mm or more) to large (φ5-10 mm) flocs in a reaction tank, and then removing and dewatering the flocs in a sludge dehydrator. ) to large (φ5 to 10 mm), and a dehydrated cake with a water content of 70% or less. After that, the desorbed liquid should be separated into a biological treatment tank ( We have discovered new knowledge that it is possible to perform biological treatment with high efficiency and precision by allowing the biological treatment to flow into an aeration tank (aeration tank).

Biomass digestive juice is in a colloidal state in which molecules such as emulsified components and particulate components associate in the digestive fluid (wastewater) to form micelles, and the emulsified and particulate components are dispersed. This is wastewater that is complexly contaminated with sludge containing such substances. For this reason, even if floc removal/dehydration is performed using a sludge dehydrator, it is extremely difficult to obtain a dehydrated cake with a moisture content of 70% or less, especially 55% or less. It has been extremely difficult to efficiently purify the biomass digestive fluid with simple equipment, at low cost, unless purification treatment is performed using equipment.

Therefore, in the present invention, in order to treat biomass digestive fluid containing wastewater that is complexly contaminated with washing wastewater, sludge containing particulate components, etc., we focus on the emulsifying components and particulate components in the digestive fluid, In order to remove these before entering the biological treatment tank (aeration tank), a specific dehydration aid and a flocculant compatible with the dehydration aid are used in combination to form flocs and remove/dehydrate them. An attempt was made to purify treated water.

That is, the present invention provides a purification facility that includes at least a mixing tank, a reaction tank, a sludge dehydrator, a (neutralization tank), and a biological treatment tank. A dehydration aid having Mp (cake moisture content) ≦70, more specifically, Mp (cake moisture content) ≦55 to Mp (cake moisture content) = 55 to 70 is added, and then, in a reaction tank, the water to be treated is A flocculant compatible with the dehydration aid, such as a polymer flocculant, is added to the floc containing the emulsified components and particulate components in the biomass digestive juice; 10 mm), and separated in a sludge dehydrator into a desorbed liquid from which the flocs have been removed and a dehydrated cake; a water content of 70% or less, more specifically, a water content of 55% or less to 55 to 70%, and then The biological treatment tank (aeration tank) efficiently performs biological treatment (purification treatment) by charging the desorbed liquid into the biological treatment tank and performing biological treatment.

In the present invention, the relationship between floc formation in the reaction tank, floc removal in the dehydration step, and cake moisture content is extremely important. As a result of the dehydration test, as shown in Table 5 (see paragraph 0067) below, when the moisture content of the cake is 90% or more, no flocs are formed, and when the moisture content of the cake is 80 to 90%, the size of the flocs is small. When the cake moisture content is 70-80%, the floc size is medium (φ3-5 mm), and when the cake moisture content is 55-70%, the floc size is large (φ5-5 mm). 10 mm), and when the cake moisture content is 55% or less, the size of the flocs is extra large (φ10 mm or more). In this order, for example, the clarity of the supernatant water changes from turbid to transparent, and the evaluation becomes rank E → A. These test results indicate that the dehydration aid added in the mixing tank It has been found that this is largely influenced by the selection of the type of flocculant added in the reaction tank, and especially the selection of the type of dehydration aid added in the former mixing tank.

The inventors of the present invention have conducted excessive or even more tests that far exceed normal routine considerations, and have determined that at least the mixing tank - reaction tank - sludge dehydrator - (neutralization tank) - biological treatment tank (aeration tank) In a purification facility equipped with a mixing tank, the water to be treated has an Mp value (moisture content evaluation) of Mp (cake water content) ≦70, more specifically, Mp (cake water content)≦55 to Mp ( a step of adding a dehydration aid having a cake moisture content) = 55 to 70, then adding a flocculant compatible with the dehydration aid, for example, a polymer flocculant, to the water to be treated in a reaction tank, By adopting a process of forming flocs that include emulsified components and particulate components in the biomass digestive fluid, it is possible to achieve a dehydrated cake with a moisture content of 70% or less, more specifically, a moisture content of 55% or less to 55-70%. The following water treatment results (effects) were obtained: floc size: extra large (φ10 mm or more) to large (φ5 to 10 mm); and supernatant water: high transparency. Then, while removing the flocs using a sludge dehydrator, the highly transparent desorbed liquid from which the flocs were removed was introduced into a biological treatment tank (aeration tank), thereby successfully implementing biological treatment efficiently.

Here, we will further discuss the formation of flocs containing emulsified components and particulate components in biomass digestive juices using a specific dehydration aid and a flocculant compatible with the dehydration aid, and their removal/dehydration. To explain in detail, in the present invention, the formation of flocs and their removal/dehydration are carried out in a purification facility equipped with at least a mixing tank, a reaction tank, a sludge dehydrator, a neutralization tank, and a biological treatment tank (aeration tank). , in the raw water (wastewater before dehydration), in a mixing tank, the Mp value (moisture content evaluation) is Mp (cake water content) ≦70, more specifically, Mp (cake water content) ≦55 to Mp (cake water content) = 55 to 70, for example, after stirring at 500 rpm for 2 minutes, in a reaction tank, add a flocculant compatible with the dehydration aid, for example, a polymer flocculant, For example, the mixture is stirred at 120 rpm for 3 minutes to form flocs containing the emulsified components and particulate components in the biomass digestive fluid. Next, the flocs are put into a sludge dewatering machine to remove/dehydrate the flocs containing the emulsified components and fine particle components in the biomass digested liquid, and separate them into a dehydrated liquid and a dehydrated cake, and the moisture content of the dehydrated cake is reduced to 70. % or less, more specifically, it means that after reducing the moisture content to 55% or less or 55 to 70%, the desorbed liquid is subjected to biological treatment in a biological treatment tank (aeration tank).

In the present invention, as the above-mentioned specific dehydration aid, for example, a dehydration aid whose main component is a pulverized product having a particle size of 1 to 100 μm obtained by pulverizing vegetable fibers by mechanical shearing, and as a coagulant. For example, a polymer flocculant (commercially available) compatible with the above-mentioned dehydration aid can be used. Here, the term ``mainly composed of a crushed product with a particle size of 1 to 100 μm obtained by crushing vegetable fibers by mechanical shearing'' means that it contains at least 50% by weight or more (that is, more than half) of the crushed product with a particle size of 1 to 100 μm. It means that something is done. The vegetable fibers that are the main components of the above-mentioned dehydration aid include, for example, wood flour from coniferous or broad-leaved trees, powder from bamboo, which is a monocotyledonous plant with a lignified culm, pulverized wood chips from thinning or woodworking shavings, or Examples include sawdust and waste generated during lumber sawing, grinding waste generated during sanding, cutting waste generated during sandblasting, papermaking pulp, and waste paper pulp. However, the material is not limited to these, and any raw material containing vegetable fiber can be used as appropriate.

These vegetable fibers preferably have a purity of 90% or more as cellulose fibers. There are more than 40 types of commercially available dehydration aids whose main ingredient is pulverized plant fibers with a particle size of 1 to 100 μm by mechanical shearing. (manufactured by Reserva), and can be obtained as appropriate by specifying the product number.

In the present invention, the "vegetable fiber" which is the main component of the dehydration aid includes, for example, vegetable fibers such as crushed rice husk, straw, crushed corncob, cellulose fiber, and fine wood flour. It is preferable to use a pulverized product (sample) whose main component is a pulverized product that has been refined to a particle size of 1 to 100 μm by pulverizing it by mechanical shearing and then pulverizing or grinding it using a grinder or the like. can do. However, the dehydration aid that can be used in the present invention is not limited to these, and has an Mp value (moisture content evaluation) of Mp (cake moisture content) ≦55 to Mp (cake moisture content) = 55 to 70. Any sample, ie, a sample ranked A to B in the evaluation section of Table 5 below, can be used in the same manner.

In the present invention, the specific dehydration aid such as the above-mentioned pulverized rice husks is added to at least a mixing tank, a reaction tank, a sludge dewatering machine (a neutralization tank ) - In purification facilities equipped with biological treatment tanks, it can be used by adding it to the water to be treated in the mixing tank. To treat biomass digestive fluid using the above specific dehydration aid, for example, add 0.1% of the above specific dehydration aid (relative to wastewater volume) to raw water (wastewater before treatment) in a mixing tank. Then, in a reaction tank, a flocculant compatible with the dehydration aid, for example, an organic polymer flocculant (for example, a 0.2% by mass aqueous solution) is added. As this organic polymer flocculant, a nonionic, cationic or amphoteric synthetic polymer flocculant is used.

Examples of the nonionic synthetic polymer flocculants include polyacrylamide, polyethylene oxide, urea-formalin resin, and examples of the cationic synthetic polymer flocculants include polyaminomethylacrylamide, polyvinylimidazoline, Examples include chitosan, ionene copolymers, and epoxyamine copolymers. Examples of the amphoteric synthetic polymer flocculants include lecithin-based amphoteric surfactants, casein decomposition product-based amphoteric surfactants, and the like. These organic polymer flocculants are appropriately available as commercial products (manufactured by Asada Chemical Industry Co., Ltd., Heimo Co., Ltd., etc.), for example. In addition, in the present invention, as a flocculant suitable for the above-mentioned dehydration aid, inorganic flocculants such as polyferric sulfate (III), polyferric chloride (III), polyaluminum chloride, polyaluminum sulfate, and ferric chloride are used. , aluminum sulfate, etc. can be used, and any appropriate flocculant can be used as long as it is compatible with the above-mentioned specific dehydration aid.

When carrying out the biomass digestive juice purification treatment of the present invention, the order in which the above-mentioned specific dehydration aid and a flocculant compatible with the dehydration aid, such as an organic polymer flocculant, are added is important. In a purification facility equipped with at least a mixing tank, a reaction tank, a sludge dehydrator, a (neutralization tank), and a biological treatment tank (aeration tank), the above-mentioned specific dehydration aid is added in the mixing tank in the previous stage, and then the reaction When a flocculant compatible with the dehydration aid, for example, an organic polymer flocculant, is added and stirred in the tank, flocs are gradually generated (formed). After sufficient floc formation, sludge dewatering is started. Execute the juice extraction process using the machine. The time required to generate (form) this floc is usually about 5 to 15 minutes.

After sufficiently forming flocs in this manner, the liquid is squeezed by, for example, a screw press, a belt press, or pressure filtration to separate the dehydrated liquid and the dehydrated cake, and the dehydrated cake is taken out. In the present invention, we focus on emulsified components and particulate components in biomass digested liquid, and in a purification facility equipped with at least a mixing tank, a reaction tank, a sludge dehydrator, a (neutralization tank), and a biological treatment tank, in a mixing tank, A dehydration aid having an Mp value (moisture content evaluation) of Mp (cake moisture content) ≦70 is added to the water to be treated, for example, a main ingredient is a crushed product of particle size 1 to 100 μm obtained by crushing vegetable fiber by mechanical shearing. Then, in a reaction tank, a flocculant compatible with the dehydration aid, such as a polymer flocculant, is added to the water to be treated to separate the emulsified components and fine particles in the biomass digestive fluid. Forms flocs containing components.

Next, in a sludge dehydrator, the flocs; If necessary, neutralize the disinfectant in the neutralization tank at the same time. Next, the desorbed liquid is put into a biological treatment tank (aeration tank) to perform biological treatment. In the present invention, it is important to form extra large (φ10 mm or more) to large (φ5 to 10 mm) flocs, and to separate the dehydrated cake from which the flocs have been removed into a dehydrated cake with a water content of 70% or less. , Only when all of these conditions are satisfied, it becomes possible to efficiently perform biological treatment using a biological treatment tank (aeration tank).

In the present invention, as the flocculant, a specific commercially available product (product number: RB-PT, PB-C1805, etc.) was selected from about 30 types of commercially available flocculants, as shown in the examples below. In the present invention, among the selection of dehydration aids and flocculants, the selection of the "dehydration aid" is the most important. ), a suitable flocculant that is compatible with the above-mentioned specific dehydration aid may be selected and used based on A to E: highest rank to lowest rank.

In the present invention, if it is not possible to separate the above-mentioned flocs; Even if the digestive fluid is biologically treated in a biological treatment tank (aeration tank), it is difficult to expect stable water treatment effects due to reduction in BOD volume burden, suppression of sludge generation amount, and reduction in required oxygen amount. As a result, it was not possible to obtain good results in the evaluation of supernatant water and evaluation of flocs (size, hardness, grip feeling), and biological treatment in the biological treatment tank (aeration tank) was not successful, preventing water pollution. It becomes impossible to construct a biomass digestive fluid treatment method and wastewater treatment equipment that meet the general wastewater standards set by the law.

The present invention provides the following special effects.
(1) In the present invention, we focus on the emulsified components and particulate components in the biomass digestive fluid containing the residue remaining after power generation in the biomass power generation facility, and flow these into the biological treatment tank (aeration tank). In order to efficiently remove the components beforehand, a specific dehydration aid and a flocculant compatible with the dehydration aid are used in combination to form flocs containing the emulsified components and particulate components in the biomass digestive fluid, and to remove the flocs. By performing removal/dehydration and, if necessary, simultaneously neutralizing the disinfectant in a neutralization tank, it became possible to carry out biological treatment in a biological treatment tank (aeration tank).
(2) By using the above-described specific dehydration aid in combination with a coagulant compatible with the dehydration aid, it is possible to discharge biomass digestive fluid in a manner that meets the general wastewater standards according to the Water Pollution Control Law.
(3) It is possible to reuse the dehydrated cake generated as a residue with a moisture content of 70% or less, more specifically, a moisture content of 55% or less to 55-70% at a composting facility.
(4) A method for efficiently biologically treating biomass digestive fluid and a wastewater treatment device (facility) for the same can be provided.
(5) According to the present invention, formation of flocs; extra large (φ10 mm or more) to large (φ5 to 10 mm) in size, a desorbed liquid from which the flocs have been removed, and a dehydrated cake; predicted (expected) cake moisture content. It was possible to separate the water content from 55% or less to 55 to 70%, making it possible to remove the BOD of raw water to 78% or less.
(6) Stable water treatment effects can be expected by reducing the BOD volume burden, suppressing the amount of sludge generated, and reducing the amount of oxygen required.

1 is a diagram schematically showing an example of a reserva dehydration system. In the figure, the flock separator is optional. 1 is a diagram schematically showing an example of a reserva dehydration system. FIG. 2 is a diagram showing a processing flow of a biomass digestive fluid (wastewater) treatment device including a purification facility equipped with a mixing tank, a reaction tank, a sludge dehydrator, and a biological treatment tank.

Next, embodiments of the present invention will be specifically described based on Examples. However, in the following examples, /D, /day, and /d each represent a value for "one day."

In this example, the wastewater treatment equipment (equipment) used for processing the biomass power generation digestive fluid of the present invention, at least raw water tank - mixing tank - reaction tank - adjustment tank - sludge dehydrator - (neutralization tank) - biological treatment tank (Aeration tank) - A wastewater treatment device equipped with a membrane treatment tank, a treated water tank, a dilution tank, and a disinfection tank will be specifically explained.
The actual capacity of the raw water tank was set to W8.0m x L8.0m x H2.2m = 140.8m ³ in order to have a capacity of more than one day's worth of the planned treatment amount. In the above raw water tank, raw water auxiliary pump; 1 unit of 50A x 0.75kw 200V, raw water pump; 1 unit of 80A x 2.2kw 200V, raw water tank stirring blower; 1 unit of 65A x 3.7kw 200V, aeration stirring device; disk 16 molds were installed.

The pretreatment reservoir dewatering equipment has a processing capacity of 140.0 m ³ /D, a load capacity of 420.0 kg/day, and a removal capacity of 420.0 kg/D x 83.3% = 349.8 kg/d (remaining capacity). SS: 2100.0 kg/D x 98.0% = 2058.0 kg/d (remaining amount 42.0 kg/d).

Mechanical equipment used: sewage metering device; 1 FRP 90° triangular weir (measuring only), mixing/reaction tank equipment; SUS W900mm x L1,800mm x H1,260mm, actual capacity 0.81m ³ /tank x 2 1 tank, 2 stirrers 200-300 rpm x 0.75 kW x 200 V (one of which is inverter controlled), flock separator; 2 SUS 0.2 kW x 200 V, special anti-clogging mechanism and automatic cleaning device Includes, screw press dehydrator (RSP-300Y type); liquid contact part made of SUS, fixed type automatic cleaning device, 2 units of 1.5kw x 200V (inverter control), dehydrated cake transfer conveyor; made of SUS, U200 type x 5m x Two 0.75kW x 200V units were installed.

The amount of dehydrated cake generated was (140.0 m ³ /d x 2.1%) ÷ (1-0.7) = 9.8 t/D, assuming that the raw water concentration was 2.1% and the water content of the dehydrated cake was 70%. Ta. The amount of the flocculation aid (Reserva MT-2000) used was 140.0 m ³ /D x 0.1% = 140.0 kg/D, assuming 0.1% addition to the liquid. The amount of polymer flocculant used is 140.0 m ³ /D x 10.5% x 0.5% = 73.5 kg/D, assuming that flocculant 1 is added at a concentration of 0.5% and 10.5% to the liquid. , 0.5% dissolved concentration solution 73.5 kg÷0.5%=14.7 m ³ /D. Assuming that flocculant 2 is added at a concentration of 0.2% and 21% to the liquid, 140.0 m ³ /D x 21% x 0.2% = 58.8 kg/D, 58.8 kg of 0.2% dissolved concentration liquid ÷ 0.2%=29.4 m ³ /D.

The actual capacity of the adjustment tank was set to W2.4m x L5.0m x H4.0m = 48.0m ³ in order to convey wastewater that flows in in 22 hours in 24 hours. In the above-mentioned adjustment tank, one adjustment pump; 50A x 0.75kw 200V; one adjustment tank diffused stirring blower; 50A x 2.2kw 200V; and six disc-type diffused stirring devices were installed.

The biological treatment tank is operated intermittently, and in order to keep the inflow BOD load below 0.2 kg・BOD/m ³ , the required capacity is 140.0 m ³ /D×500 mg/l ÷ 0.2 kg・BOD/m ³ - Day = ^350.0m3 . Actual capacity is W5.0m x L6.6m x H4.0m = 132.0m ³ , W4.2m x L6.6m x H4.0m = 110.88m ³ , W3.0m x L6.6m x H4.0m = 79.2m ³ , W5.0m x L4.0m x H4.0m (membrane treatment tank) = 80.0m ³ , total 402.08m ³ . The required capacity is O ₂ = (0.8 x 70.2 kg/D) + (0.07 x 5 kg/m ³ x 402.08 m ³ ) = 196.89 kg/d, O ₂ = 196.89 kg/ d÷0.49kg/m ³ ÷0.04=10,045.5m ³ /d=10.1m ³ /min.

The membrane treatment tank is 24H/D (8 minutes operation - 2 minutes washing), and in order to make the permeation flow rate 0.275m ³ /m ² ·D, the required number of membranes is 140.0m ^{3 /} D ÷ 0.275m. ³ /m ² ·D ÷ 0.8 m ² /sheet ÷ 0.8H = 796 membranes, and the number of membranes used was 200 membranes/group x 4 membranes = 800 membranes. The amount of air required for membrane processing was set to 10 L/min x 800 sheets = 8.0 m ³ /min in order to set the air amount per membrane to 10 L/min. The return circulation ratio was set to 5 times or more. Return to the above membrane treatment tank 4 units of immersion type membrane separator; pore size 0.1-0.4 μm, 200 sheets/unit; 2 units of membrane blower; 65A x 45kPa x 4.1m ³ /min x 5.5kW; One circulation pump, 50A x 1.5kw, and two membrane treated water pumps, 40A x 0.75kw (land-based corrosion resistant type) were installed.

In order to make the treated water tank have a capacity that can store membrane treated water for 12 hours, the required volume is 140.0 m ³ /D<5.84 m ³ /h x 12 hours = 70.08 m ³ and the actual volume is W1. 8m x L (6.6m + 5.9m) x H3.5m = ^78.75m3 . One treated water transfer pump 65A x 2.2 kW was installed in the treated water tank.

In order to store the dilution water (well water + membrane treated water) for one day, the required volume of the dilution water tank is 70 m ³ /D, and the actual volume is W4.5m x L5.0m x H3.5m = The total area was ^79.0m3 . One dilution water transfer pump 65A x 2.2 kW (well water solenoid valve 40A) was installed in the dilution water tank.

The disinfection tank equipment had a throughput of 140.0 m ³ /D. In order to inject 10 mg/L for the treatment amount, the required amount of chlorine is 140.0 m ³ /D x 10 mg/L x 10-3 = 1.40 kg/D, 1.40 kg/D ÷ 70% = 2 .0 kg/D. One sterilizer (hypochlorous acid tablet dissolving method, PVC type, 15 kg type) was installed in the above disinfection tank equipment.

In this example, the following configurations were installed in Example 1: Raw water tank - Mixing tank - Flock separator - Screw press dehydrator - Adjustment tank - Measuring tank - Biological treatment tank (aeration tank) - Membrane treatment tank - Treated water tank - Dilution tank - Using a disinfection tank (→ outflow) (see Figure 3), use “crushed rice husks”; vegetable fiber rice as a dehydration aid with an MP value (moisture content evaluation) of MP (cake moisture content) ≦70. Crushed rice husks (sample) whose main component was pulverized rice husks with a particle size of 1 to 100 μm were used by mechanical shearing. In addition, in the following examples, "Reserva" (manufactured by Reserva Co., Ltd., product numbers: MT2000, MT5000, MT7000), which is a commercial product equivalent to the above-mentioned "ground rice husks", was used as a sample. These reserva products are products in which pulverized cardboard is added to the main ingredient, pulverized rice husks, and are divided into product numbers based on the difference in content.
In addition to these Reserva products, there are also commercially available products (manufactured by Reserva Co., Ltd.) that contain, for example, ground wheat straw, straw and/or corn cob in addition to the main ingredient, pulverized rice husks. available.

(1) Selection of flocculant As a sample of the object to be treated, biomass power generation digestive fluid [water quality after pretreatment; pH value: 7.5-8.5, BOD value: 500 mg/l (removal rate 83.3%) , SS value: 300 mg/l (removal rate 98.0%)], and 0.1% (relative to sludge volume) of the sample (commercial product) Reserva (MT2000) as a dehydration aid was added to 100 ml of the sludge. Approximately 30 types of flocculants (polymer flocculants, etc.) were added, and the reaction was confirmed. For example, a flocculant (RB-C1805) was added at an addition rate of 46%, and flocculation was determined.

The results are shown in Table 1. The judgment conditions were A to E; A was the highest rank and E was the lowest rank. The evaluation of the supernatant water was the best A++ among all product numbers for the flocculant RB-C1805, so from among about 30 types of flocculants, we selected the flocculant (RB-C1805) and the dehydration aid Reserva (MT2000). was selected as a flocculant (polymer flocculant compatible with dehydration aid).

(2) Selection of dehydration aid Next, in order to select a specific crushed product that can be used in the present invention as a dehydration aid from among crushed products obtained by crushing vegetable fibers by mechanical shearing, 100 ml of sludge was , commercially available products (reserva MT2000, MT5000, and MT7000 manufactured by Reserva) were added at 0.1% each (relative to sludge volume), and floc judgment (supernatant water, size, hardness) was performed. , grip feeling) and overall evaluation.The results are shown in Table 2.The judgment conditions were A to E; A was the highest rank and E was the lowest rank.

When the reaction was confirmed, the evaluation of the supernatant water in the floc judgment was A+++, which is the best among all product numbers for MT7000, so MT7000 was selected as the dehydration aid reserva. Therefore, in the following dehydration test of this example, the dehydration aid was equivalent to a pulverized product (sample) whose main component was a pulverized product with a particle size of 1 to 100 μm obtained by pulverizing vegetable fiber rice husks by mechanical shearing. We decided to use the commercially available product "Reserva (MT7000)".

(3) Dewatering test To 600 ml of sludge, add the dewatering aid "Reserva (MT7000)" and add flocculant (product number: RB-C1805) at an addition rate of 46% (based on sludge volume, 0.2% aqueous solution). to form flocs. Next, the flocs are put into a dehydration tester equipped with a screw press dehydrator, a dehydration test is performed, and the dehydrated liquid from which the flocs have been removed is separated into a dehydrated cake. Analysis was carried out. The dehydration pressure and holding time were based on a screw press dehydrator. The results are shown in Table 3. By adding 0.1% of Reserva, the moisture content of the dehydrated cake was 59.03%.

(4) Water quality analysis of dehydrated liquid Water quality analysis (BOD, COD, SS , TN analysis) was conducted at a public institution. The results are shown in Table 4. It was confirmed that 86.5% of BOD, 91.8% of COD, 99.8% of SS, and 54% of TN were removed by Reserva dehydration.

(5) Summary Reserva dehydration confirmed a significant reduction in all items of water quality analysis of the desorbed liquid. It turns out that this can lead to a significant reduction in the construction cost of septic tanks. It was confirmed that the moisture content of the cake was reduced to 59.3% through Reserva dehydration, and the amount was reduced to 1/18th of the current amount compared to the case where the entire amount was disposed of due to unprocessable conditions. .

Further, a suitable coagulant has a product number of RB-C1805 and an addition rate of 46% (relative to sludge volume, 0.2% aqueous solution), and a suitable reservoir has a product number of MT7000 and an addition rate of 0. It was 1% (relative to sludge volume).

Evaluation of supernatant water: cloudy → transparent, evaluation of flocculation: A to E, “Size”: cannot be flocculated, small (φ3 mm or less), medium (φ3 to 5 mm), large (φ5 to 10 mm), extra large (φ10 mm or more) , "Hardness": soft → hard, "grip feeling": unable to grasp → can be firmly grasped, Expected (expected) cake moisture content: 90% or more, 80-90%, 70-80%, 55-70%, The results of 55% or less are summarized in Table 5.

According to the above dehydration test, the supernatant water was transparent (the size of the flocs was extra large (φ10 mm or more)), and the moisture content of the dehydrated cake was 59.3%, which was 55 to 70%. In addition, in the present invention, not only when a dehydration aid with MP (cake moisture content) ≦55 is used, but also when a dehydration aid with MP (cake moisture content) = 55 to 70% is used, the supernatant water is almost transparent (the size of the flocs is large (φ5 to 10 mm)), and if the moisture content of the dehydrated cake is in the range of 55 to 70%, the purified liquid phase can be disposed of in the river. It was confirmed that it can be purified.

In this example, the target sample was digested sludge from a municipal (K City) sewage treatment plant, and the sample was purified.

(1) Selection of flocculant Sludge [Properties of sample: TS (solids) concentration: 1.33%, pH: 7.25. Appearance: cloudy color, odor: charcoal odor, fibrous material (100 mesh): 5.2%/ss, fibrous material (200 mesh): 14.2%/ss] Add 0.1 of Reserva MT2000 to 100ml. % (relative to sludge volume), and approximately 30 types of flocculants (including flocculants designated by K City) were added to each, and the reaction was confirmed. Table 6 shows the results.

When the reaction was confirmed, the "grip feeling" evaluation in the floc evaluation was B-, so the flocculant designated by the local government (K City) was selected.

(2) Selection of Reservoir To 100ml of sludge, 0.1% (relative to sludge volume) of three types of Reservoir, MT2000, MT5000, and MT7000, was added to confirm the reaction. Table 7 shows the results.

After checking the reactions, we selected Reserva MT2000, which received the highest evaluation of "grip feeling" among all the product numbers based on flocking.

(3) Dewatering test Reserva MT2000 was added to 500 ml of sludge, and a polymer flocculant (0.2% aqueous solution) was added to form flocs. A dehydration test was performed by putting the flocs into a dehydration tester (pressure area: 81 cm ² , variable pressure/holding time type), and the water content of the discharged dehydrated cake was measured. The dehydration pressure and holding time were set assuming a screw press dehydrator. Table 8 shows the results.

By adding 0.04% of Reserva (3% of TS addition rate), the cake moisture content was 78.67%. By adding 0.1% of Reserva (7.5% of TS addition rate), the cake moisture content became 74.18%. By adding 0.3% of Reserva (addition rate of TS: 22.5%), the moisture content of the cake was 69.92%.

(4) Water quality analysis of desorbed water The raw water (water before dehydration), the SS value after desorption in the dehydration test, and the TP value were measured at a public institution. Table 9 shows the results.

(5) Recovery rate of SS The recovery rate of SS was 99.6% with the addition of 0.1% Reserva (compared to the TS addition rate of 7.5%) and the flocculant specified by the local government (K City). 3% addition (22.5% of TS addition rate), 99.75% using a flocculant designated by the local government (K City), 0.1% addition of Reserva (7.5% of TS addition rate), polymer It was 99.7% with the flocculant (0.2% aqueous solution), and 99.7% with the addition of 0.3% Reserva (22.5% of TS addition rate) and the polymer flocculant (0.2% aqueous solution). It was 76%.

(6) Recovery rate of TP The recovery rate of TP was 81% with the addition of 0.1% Reserva (compared to the TS addition rate of 7.5%) and the flocculant designated by the local government (K City). Addition of 0.3% (addition rate of TS 22.5%), 81% due to the flocculant specified by the local government (K City), addition of 0.1% of Reserva (addition rate of TS 7.5%), polymer With the flocculant (0.2% aqueous solution), it was 78.4%, and with the addition of 0.3% Reserva (22.5% of TS addition rate) and the polymer flocculant (0.2% aqueous solution), it was 80. It was 6%.

(7) Summary The preferred reservoir product number is MT2000, and the addition rate is 0.04% to 0.3% (relative to sludge volume), and the addition rate to TS is 3% to 22.5% (sludge volume). (0.4 kg to 3 kg was used per 1 ^m3 ). In addition, the preferred coagulant product number is a coagulant specified by the local government (K City), and the addition rate is 12% (0.2% aqueous solution), and the addition rate to TS is 1.8% (sludge volume 1 m ³ , 0.24 kg was used).

The preferred coagulant product number is a coagulant designated by the local government (K City), and the addition rate is 12% (0.2% aqueous solution), and the addition rate is 12% ( ^0.2% aqueous solution). ) was 1.8%. By reserva dehydration, the cake moisture content was 69.92% to 78.67%, the recovery rate of SS was 99.6% to 99.75%, and the recovery rate of TP was 81%. there were.

Evaluation of supernatant water: turbid → transparent, and evaluation of flocculation: “size” is non-floccable, small (φ3mm or less), medium (φ3-5mm), large (φ5-10mm), extra large (φ10mm or more). "Hardness" goes from soft to hard, "grip feeling" goes from not being able to grip to being able to grip firmly, and the overall "evaluation" is E to A, with "expected (expected) cake moisture content". The rates were 90% or more, 80-90%, 70-80%, 55-70%, and 55% or less (see Table 5).

In this example, it was verified whether the moisture content of the cake could be reduced by dehydrating the biomass digestive fluid.

(1) Confirmation of sludge properties As a sample, biomass digestive liquid (wet methane fermentation digestive liquid of food waste raw material [sample properties: TS (solids) concentration: 5.49%, pH: 7.59. Appearance: black Cloudy color, odor: nitrification odor]) was used as the target sample.

(2) Dewatering test To 300 ml of sludge, a dewatering aid, Reserva (MT2000), was added, and a polymer flocculant A (0.2% aqueous solution) was added to form flocs. The flocs were put into a dehydration tester (pressure area: 81 cm ² , variable pressure/holding time type) to perform a dehydration test, and the water content of the discharged cake was measured. The dehydration pressurization/holding time was 2,000 G for 1 minute assuming a centrifuge, and 490 kPa for 5 minutes assuming a screw press. Table 10 shows the results.

As a result of adding Reserva MT2000 and polymer flocculant A (0.2% aqueous solution) and dehydrating using a centrifuge, the cake moisture content was 77.62%. Further, Reserva MT2000 and polymer flocculant A (0.2% aqueous solution) were added, and the cake was dehydrated using a screw press, and the moisture content of the cake was 67.92%. There was almost no leakage of SS into the desorbed liquid in the test assuming a centrifuge, and there was also a small amount in the test assuming a screw press.

(3) Summary Due to Reserva dehydration, the cake moisture content was 77.62% in a centrifuge simulation test, and dehydration to 75% or less using a centrifuge was considered impossible due to the low dehydration pressure. In addition, the moisture content of the cake was 67.92% in a test assuming a screw press machine, so it was determined that dehydration to 75% or less was possible using a screw press machine.

In this example, the digestive fluid generated in a biomass power generation facility was dehydrated.

The sample was digested fluid from biomass power generation [sludge before solid-liquid separation; TS (solids) concentration: 4.36%, pH: 7.51, appearance: cloudy black, odor: nitrification odor, sludge after solid separation. ; TS (solids) concentration: 1.04%, pH: 8.14, appearance: brown, odor: nitrification odor] was used to conduct a dehydration treatment test of the digestive fluid. There was a difference of more than 4 times in TS (solid matter) concentration before and after solid-liquid separation.

(1) Selection of flocculant To 100 ml of sludge, add Reserva MT2000, a dewatering aid, and each of about 20 types of flocculants, check the compatibility between Reserva and sludge, and perform a reaction to select the product number. It was confirmed. Table 11 shows the results. The compatible coagulant had the same product number for the sludge before and after solid-liquid separation. There was a 1.6 times difference in the amount of flocculant added between the sludge before and after solid-liquid separation.

(2) Dewatering test Reserva (MT2000) was added to the sludge at an addition rate of 0.05% (relative to wastewater volume), and polymer flocculant A was added to form flocs. A dehydration test was performed by putting the flocs into a dehydration tester (pressure area: 81 cm ² , variable pressure/holding time type), and the water content of the discharged dehydrated cake was measured. The dewatering pressure and holding time were 480 kPa and 5 minutes assuming a screw press dehydrator. Table 12 shows the results.

(Sludge before solid-liquid separation)
Reserva MT2000 and polymer flocculant A (0.2% aqueous solution) were added to 500 ml of sludge in an amount of 340 ml, and dewatered using a screw press, resulting in a cake moisture content of 69.01%.
(Sludge after solid-liquid separation)
Reserva MT2000 and polymer flocculant A (0.2% aqueous solution) were added to 700 ml of sludge in an amount of 300 ml, and dewatered using a screw press, resulting in a cake moisture content of 73.88%.

(3) Water quality analysis We conducted water quality analysis of raw waste water (water before dehydration) and the desorbed liquid from the dehydration test. TN was conducted at a public institution, and BOD was conducted using a BOD meter. Table 13 shows the results.

(Sludge before solid-liquid separation)
Reserva dehydration removed 63.6% of BOD to 480 mg/l. For TN, the removal rate remained at 35%. Most of the remaining nitrogen was thought to be ammonia nitrogen.
(Sludge after solid-liquid separation)
Reservoir dehydration removed 83.5% of BOD to 400 mg/l.

(4) Summary As the BOD was reduced to 1/3 by Reserva dehydration treatment, it was found that the planned installation capacity of the biological treatment tank (aeration tank) would be 1/3 of that for treating raw water as is. It was also found that the moisture content of the cake was in the low 70% range, making subsequent processing easier and making plans for composting and industrial waste disposal easier.

In this example, the digestive fluid (high concentration) from biomass power generation was used to dehydrate the digestive fluid.

As a sample, digested fluid from biomass power generation [wastewater properties: TS (solids) concentration: 81.17%, pH: 8.05, appearance: dark brown, odor: low nitrification odor) was used. The TS (solid matter) concentration was very high at 8%, and in subsequent tests, a 2-fold dilution of this was used.

(1) Dehydration test To 300 ml of wastewater, a dehydration aid, Reserva (MT2000), was added at a rate of 0.05% (relative to wastewater volume), and flocculant A or B was added to form flocs. The flocs were put into a dehydration tester (pressure area: 81 cm ² , variable pressure/holding time type), a dehydration test was conducted, and the water content of the discharged cake was measured. The dehydration pressure/retention test was conducted at 480 kPa for 5 minutes assuming a screw press dehydrator. Table 14 shows the results.

As a result of adding Reserva MT2000, 60 ml of flocculant A (0.5% aqueous solution), 120 ml of flocculant B (0.2% aqueous solution), and dehydration using a screw press, the cake moisture content was 61 It became .1%.

(2) Water quality analysis BOD measurements of the wastewater raw water (water before dehydration) and the desorbed liquid from the dehydration test were performed using a BOD meter. Table 15 shows the results.
In the Reserva dehydration, 82.2% of BOD was removed, resulting in 535 mg/l. Visual confirmation showed that most of the SS was removed. The dilution ratio of the raw water is preferably 2 times or more, and in the reserva dehydration treatment, the cake water content was 61.1%, 82.2% of BOD was removed, and the volume was 535 ml.

In this example, tests were conducted to determine how much the BOD and SS concentrations could be lowered and how much the cake water content could be lowered by subjecting the biomass digestive fluid to a reservoir dehydration process. FIG. 1 schematically shows an example of the reservoir dewatering system used in this example. In the figure, a flock separator is shown as an option.

Biomass digestive fluid [sample properties: TS (solids) concentration: 4.17%, pH: 7.50, appearance: dark brown, odor: nitrification odor] was used as the wastewater of the sample to be treated. Dehydration tests and water quality analysis tests were conducted.

(1) Dehydration test To 500 ml of wastewater, add 0.30% (based on wastewater volume) of Reserva (MT2000), a dehydration aid, 150 ml of flocculant A (0.5% aqueous solution), and flocculant B (0.2 % aqueous solution) was added to form flocs. Water is removed from the floc using a filter cloth, and the moisture is used as desorbed water for a subsequent water quality analysis test.The solids are dehydrated by putting them into a dehydration tester (pressure area 81 m ² , variable pressure and holding time). A test was carried out and the moisture content of the discharged cake was measured. The dewatering pressure and holding time were 480 kPa and 5 minutes assuming a screw press dehydrator. Table 16 shows the results.

As shown in the table, the moisture content of the cake was 71.95% by adding Reserva MT2000 and adding flocculants A and B for dehydration. The amount of flocculant added varies depending on the biomass raw material, but in the case of biomass digestive fluid derived from cow dung or chicken dung, the amount added tends to be large.

(2) Water quality analysis test Measurements of BOD, SS (suspended solids), phosphorus, and nitrogen in the raw wastewater (water before dehydration) and the dehydrated liquid in the dehydration test were conducted by a public organization (environmental measurer). Table 17 shows the results.

The BOD of wastewater raw water (water before dehydration) is removed by 90.5%, and the BOD of Reserva dehydration and dehydrated liquid is reduced from 4,300 mg/l to 410 mg/l, and the water treatment effect of Reserva is significantly demonstrated. This was confirmed. In addition, 99% of the SS in the wastewater raw water (water before dehydration) was removed, and the SS of the Reserva dehydration solution decreased from 26,000 mg/l to 25 mg/l, indicating that Reserva's water treatment effect was remarkable. It was confirmed that it works.

By Reserva dehydration, 90.5% of the BOD of the wastewater raw water (water before dehydration) was removed, and 99.9% of the SS of the Reserva desorbed liquid was removed to 25 mg/l. Furthermore, the cake moisture content was as low as 71.95%. From these values, it was confirmed that reservoir dehydration of biomass digested fluid can be performed with high efficiency in both dehydration and water treatment performance.

(3) Summary It was confirmed that the water content of the dehydrated cake was reduced to 75% to 65% by dehydration treatment using Reserva, and that the water content can be freely set by increasing or decreasing the amount of Reserva added. A water quality analysis test of the Reserva dehydration and dehydration solution revealed that phosphorus in the Reserva dehydration and dehydration solution was removed by an average of 95%, SS (suspended solids) by an average of 95%, BOD by an average of 60%, and nitrogen. was confirmed to be removed by an average of 60%. It was confirmed that the dewatering system using the reserva can be used as a water treatment system and as a water recycling technology.

In this example, tests were conducted to determine how much the BOD and cake dehydration rate could be reduced by subjecting the digestive fluid generated in biomass power generation to a reservoir dehydration process. A reserva dehydration system similar to that used in Example 7 was used.

(1) Dewatering test To 500 ml of sludge, 90 ml of dewatering aid Reserva (MT2000) and polymer flocculant A (0.2% aqueous solution) were added to form flocs. The flocs were put into a dehydration tester (pressure area: 81 cm ² , pressure/holding time variable) to conduct a dehydration test, and the moisture content of the discharged cake was measured. The dewatering pressure and holding time were 480 kPa and 5 minutes assuming a screw press dehydrator. Table 18 shows the results.

As shown in the table, as a result of adding 0.30% of Reserva MT2000 (relative to waste water volume), adding 90 ml of polymer flocculant A (0.2% aqueous solution), and dehydrating using a screw press, the cake water content was was 72.75%.

(2) Water quality analysis test Waste water raw water (water before dehydration) and the dehydrated liquid from the dehydration test were measured using a BOD meter (Central Kagaku Co., Ltd., OxiTop System). Table 19 shows the results. By Reserva dehydration, the BOD of raw waste water (water before dehydration) was halved from 6,920 mg/l to the BOD of Reserva dehydration solution (water after dehydration) of 3,450 mg/l.

It was confirmed that the BOD of wastewater raw water (water before dehydration) was halved by Reserva dehydration treatment, and the design capacity of the biological treatment tank (aeration tank) was halved compared to when the raw solution was treated as is. It was also confirmed that the moisture content of the cake was in the low 70% range, making subsequent processing easier and making plans for composting and industrial waste disposal easier.

(3) Summary It was confirmed that the water content of the dehydrated cake was reduced to 75% to 65% by dehydration treatment. As a result of the water quality analysis test of the dewatered liquid from Reserva dehydration, it was found that phosphorus was removed by an average of 95%, SS (suspended solids) was removed by an average of 95%, BOD was removed by an average of 60%, and nitrogen was removed by an average of 60%. was confirmed. It was confirmed that the Reserva dewatering system can be used as a recycling technology for water treatment systems.

In this example, by dehydrating the biomass power generation digestive fluid, the cake water content was measured and the water quality analysis test of the reserva dehydrated and dehydrated fluid was conducted.

In this example, sludge [sludge properties: TS (solids) concentration: 2.73%, pH: 7.63, appearance: dark brown blackish brown, odor: slight putrid odor] was used as a sample, and the sludge was dehydrated. Tests and water quality analysis of Reserva dehydration and desorption fluid [phosphorus, SS (suspended solids), BOD, nitrogen] were conducted. FIG. 2 schematically shows an example of the reservoir dewatering system plant used in this example.

(1) Dewatering test To 800 ml of sludge, 0.10% (based on sludge volume) of Reserva (MT2000), a dehydration aid, was added, and a polymer flocculant (0.2% aqueous solution) was added to form flocs. . The flocs were put into a dehydration tester (pressure area 81 cm ² , pressure and holding time variable), a dehydration test was conducted, and the moisture content of the discharged cake was measured. The dewatering pressure and holding time were 480 kPa and 5 minutes assuming a screw press dehydrator. Table 20 shows the results.

As shown in the table, as a result of adding 0.1% of Reserva MT2000 and 100ml of polymer flocculant (existing product) (1.5% of TS) and dehydration assuming a screw press, the cake moisture content was 72.11%. It became. Although sludge is originally easy to dehydrate, it was confirmed that adding Reserva almost eliminates SS leakage and promotes subsequent fermentation. As a result of dehydration by adding Reserva, the cake moisture content was 72.11%, and it was confirmed that further reduction was possible by increasing the amount added.

(2) Water quality analysis test A water quality analysis test of Reserva dehydrated and desorbed liquid was conducted. As a result, dehydration effects were obtained in which phosphorus was removed by an average of 95%, SS (suspended solids) by an average of 95%, BOD by an average of 60%, and nitrogen by an average of 60%. It was confirmed that the water content can be freely set by increasing or decreasing the amount of reservoir added. It was confirmed that the Reserva dewatering system can be used as a recycling technology for water treatment systems.

In this example, it was investigated how much the moisture content of the cake could be reduced by dehydrating the sludge of ink cleaning wastewater.
In this example, ink cleaning wastewater sludge [sludge properties: TS (solids concentration: 0.45%, pH: 6.24, appearance: cloudy and slightly transparent color, odor: mineral oil smell) was used as a sample. , Reserva dehydration test, and water quality analysis test of Reserva dehydration and dehydrated liquid [phosphorus, SS (suspended solids), BOD, nitrogen].

(1) Dewatering test To 800 ml of sludge, add 0.3% (relative to sludge volume) of the dewatering aid Reserva (MT2000) and 75 ml of polymer flocculant A (0.2% aqueous solution) to form flocs. I let it happen. The flocs were placed in a dehydration tester (pressure area: 81 cm ² , pressurization/holding time variable), and the moisture content of the discharged cake was measured. The dewatering pressure and holding time were 960 kPa for 10 minutes assuming a filter press dehydrator, and 480 kPa for 5 minutes assuming a screw press machine. Table 21 shows the results of the dehydration test.

As shown in the table, as a result of adding Reserva MT2000 and polymer flocculant A and dehydrating assuming a filter press, the cake moisture content was 72.74%. It was 77.54%. As a result of Reserva dehydration, the moisture content of the cake became 72.74% to 77.54%, which was a reduction of 15% to 20% or more from the current state. This reduced the amount of dehydrated cake to 1/3 of the current amount.

(2) Dehydration effect The moisture content of the cake can be freely set by increasing or decreasing the amount of reserva added, and as a water treatment effect, an average of 95% of phosphorus is removed, and an average of 95% of SS (suspended solids) is removed. It was confirmed that 60% of BOD and 60% of nitrogen were removed on average. It was confirmed that the Reserva dewatering system can be used as a recycling technology for water treatment systems.

As detailed above, the present invention relates to a method for treating biomass digestive fluid and a wastewater treatment device thereof. In order to efficiently remove these before flowing into the aeration tank, the Mp value (moisture content evaluation) should be set to Mp (cake moisture content) ≦70, more specifically, Mp (cake moisture content) ≦55 to Mp (cake moisture content). ) = 55 to 70 in combination with a flocculant and the formation of flocs that include emulsified components and fine particle components in the biomass digestive fluid, as well as floc removal/dehydration. Biological treatment using a treatment tank (aeration tank) is now possible; 2) By using the specific dehydration aid and flocculant in combination, biomass digestive fluid is discharged in a manner that meets the general wastewater standards stipulated by the Water Pollution Prevention Act. 3) It is possible to reuse the dehydrated cake generated as a residue in a composting facility. 4) A method for efficiently biologically processing biomass digested fluid and its wastewater treatment equipment (facility) 5) According to the present invention, a desorbed liquid from which flocs; % or less to 55-70%, making it possible to remove the BOD of raw water to less than 78%. 6) Reducing the BOD volume burden, suppressing the amount of sludge generated, and reducing the amount of oxygen required. It has industrial applicability in that stable water treatment effects can be expected.

Claims (5)

A method for treating digested sludge forming an emulsion, the method comprising:
The digested sludge of the water to be treated is mainly composed of pulverized vegetable fibers with a particle size of 1 to 100 μm by mechanical shearing, and the Mp value (moisture percentage value; moisture content evaluation) is ≦ Mp (cake moisture content) ≦ 55 to Mp (cake moisture content) = 55 to 70, and a flocculant having the ability to form fluff (Flock) are added to form flocs; extra large (φ10 mm or more) to large (φ5 10 mm), a step of separating the desorbed liquid from which the flocs have been removed and a dehydrated cake; a water content of 55% or less to 55-70%; then, the desorbed liquid is transferred to a biological treatment tank (aeration tank ) and performing biological treatment. In a purification facility equipped with at least a mixing tank, a reaction tank, a sludge dehydrator, a (neutralization tank), and a biological treatment tank, a step of adding the specific dehydration aid to the digested sludge of the water to be treated in the mixing tank; Next, in a reaction tank, a flocculant having floc-forming ability is added to the water to be treated to form flocs containing emulsified components and fine particle components in the digested sludge; extra large (φ10 mm or more) to large (φ5 to 10 mm). a step of removing the flocs in a sludge dewatering machine and simultaneously separating the dehydrated liquid from which the flocs have been removed and a dehydrated cake with a water content of 55% or less to 55-70%; The treatment method according to claim 1, comprising the step of performing biological treatment by introducing the liquid into a biological treatment tank (aeration tank). 3. The treatment method according to claim 1, wherein an operation for removing flocs containing emulsified components and particulate components in the digested sludge is performed before the water to be treated flows into the biological treatment tank. A wastewater treatment device for use in the method for treating digested sludge according to any one of claims 1 to 3, comprising:
The components include a purification facility equipped with at least a mixing tank, a reaction tank, a sludge dewatering machine, a neutralization tank, and a biological treatment tank,
1) In the mixing tank, the digested sludge forming an emulsion of the water to be treated is mixed with the main component of crushed vegetable fibers with a particle size of 1 to 100 μm by mechanical shearing, and the Mp value (moisture content evaluation) is added. a step of adding a dehydration aid having Mp (cake moisture content) ≦55 to Mp (cake moisture content) = 55 to 70;
2) In the reaction tank, a flocculant with floc-forming ability is added to the water to be treated to form flocs that include emulsified components and fine particle components in the digested sludge; extra-large (φ10 mm or more) to large (φ5-10 mm) The process of making
3) A step of separating the dehydrated liquid from which the flocs have been removed and a dehydrated cake with a water content of 55% or less to 55 to 70% using a sludge dehydrator;
The above-mentioned wastewater treatment apparatus is characterized in that the desorbed liquid is introduced into a biological treatment tank (aeration tank) to carry out biological treatment. 1) A step of adding a dehydration aid having an Mp value (moisture content evaluation) of Mp (cake water content) = 55 to 70 to the digested sludge of the water to be treated in a mixing tank;
2) A step of adding a flocculant to the water to be treated in a reaction tank to form large flocs (φ5 to 10 mm) that include emulsified components and fine particle components in the digested sludge;
3) A step of separating into a dehydrated liquid from which the flocs have been removed and a dehydrated cake with a water content of 55 to 70% using a sludge dehydrator;
The wastewater treatment apparatus according to claim 4, wherein the desorbed liquid is introduced into a biological treatment tank (aeration tank) to carry out biological treatment.