JP2003225513A - Flocculant for treating washing wastewater of food - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning means for food washing wastewater high in safety capable of preventing water pollution, low in equipment cost and running cost, capable of reducing the amount of industrial waste and capable of converting the industrial waste to valuable matter. <P>SOLUTION: This flocculant for treating food washing wastewater is used for the cleaning means and contains an ion exchanging/adsorbing component (a), a coagulation component (b), and a sedimentation assisting component (c), but substantially contains no chlorine component. Artificial zeolite is compounded as the ion exchanging/adsorbing component. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cleaning wastewater treatment of foods, which prevents water pollution, has low equipment and running costs, can reduce industrial waste, and can be converted into valuable materials, with high safety. The present invention relates to a flocculant for use.

[0002]

2. Description of the Related Art In recent years,
It has been pointed out that the sharpening soup of rice (washing wastewater) will worsen the environment. In particular, with the recent industrialization of unwashed rice, a large amount of sharpening juice will be discharged, and the rice bran from this sharpening juice contains BOD substances (organic substances), nitrogen, phosphorus, etc. Causes water pollution. The amount of this nuka is about 400,000 tons nationwide. Discharging sharpening juice into rivers or seas where sewers or combined septic tanks are not maintained may cause harmful effects due to water pollution or insufficient treatment capacity of sewage treatment facilities.

At present, a large-scale facility such as an activated sludge method is required for the treatment of rice rinsing wastewater, so that the facility is expensive and the running cost is high. In addition, agglomerates such as nuka, which are formed when treating the waste water for washing rice, are discarded as industrial waste. The same applies to washing wastewater for general foods, which includes substances that cause water pollution, not limited to rice polishing juice.

For this reason, the development of an excellent purification means which can be widely applied to the washing wastewater of foods such as rice polishing juice, and further,
Since it is expected that industrial waste will be reduced, it has been desired to convert agglomerates and the like generated from washing wastewater of foods into highly valuable resources that are not harmful to living organisms and the natural environment.

On the other hand, in the treatment of general industrial wastewater, a coagulant is added to the wastewater to form a coagulum by a large-scale facility.
This is separated and removed to purify water. Therefore, it may be possible to apply such a coagulant to food washing wastewater in a reduced scale. However, polyaluminum chloride (PA), which is widely used as a raw material for inorganic flocculants, is generally used as a flocculant for treating general industrial wastewater.
C), polyiron chloride, calcium chloride, and other chlorine content harmful to living organisms are used.

Further, since the agglomerates formed by such a flocculant usually also contain chlorine, it is impossible to use such flocculants to convert the washing wastewater of foods into valuable substances with high safety. is there. In particular, when a flocculant containing chlorine is applied to a plant-growing soil, it deteriorates the soil, and therefore it is not possible to use such flocculant to convert food washing wastewater into a valuable resource for soil such as fertilizer. It should be noted that aggregates formed from aggregating agents for treating general industrial wastewater are also treated as industrial wastes.

Therefore, the present invention provides a highly safe means for purifying food washing wastewater which prevents water pollution, has low equipment and running costs, can reduce industrial waste, and can be converted into valuable materials. The challenge is to provide.

[0008]

Means for Solving the Problems As a result of earnest studies, the present inventor has achieved the above-mentioned problems by using an aggregating agent which contains an artificial zeolite as a specific component and which does not substantially contain a specific harmful substance. We have obtained the knowledge that

The present invention has been made on the basis of the above-mentioned findings, and is a flocculant containing at least (a) an ion exchange / adsorption component, (b) a coagulation component, and (c) a coprecipitation component. The present invention provides an aggregating agent for treating food waste water, which comprises artificial zeolite as an ion-exchange / adsorption component and contains substantially no chlorine.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below based on its preferred embodiments. The coagulant of the present invention is applied to the treatment of food wastewater, and is one of the components (a) which is an artificial zeolite as an ion exchange / adsorption component, and has a substantial chlorine content. It is not included in.

Since the flocculant of the present invention is prepared by mixing the artificial zeolite [component (a)] as described above, when the food is washed due to its ion exchange function and adsorption function. It is possible to form an aggregate while promoting the aggregation action on the generated wastewater, and to adsorb a malodorous component generated when the aggregate is formed. As a result, the flocculant of the present invention can promote the conversion of food washing wastewater into valuable substances, and the obtained flocculates can be effectively used by converting them into valuable substances free of malodorous components. Especially when the obtained aggregate is used as a fertilizer as a valuable resource for soil, it absorbs the nutrients (active ingredients) of the fertilizer sprinkled on the soil and suppresses the nutrient flow by rainwater etc. You can

The aggregating agent of the present invention, as described above,
Since it does not substantially contain chlorine, it is highly safe for the natural environment such as living things and soil. As a result, the flocculant of the present invention can effectively use the obtained flocculate as a valuable resource. In addition, "substantially free" does not mean that it does not include an amount (trace amount) such that the effect on living things and the natural environment can be ignored.

As described above, the flocculant of the present invention is highly safe and can collect flocculates as valuables, so that it is possible to prevent water pollution due to discharge of wastewater into rivers and the sea. In addition, the amount of industrial waste can be reduced, and since large-scale equipment is not required for wastewater treatment, equipment and running costs are low.

The blending amount of the artificial zeolite of the component (a) used in the present invention is preferably 10 to 40% by weight, more preferably 15 to 40% by weight in the aggregating agent from the viewpoint of improving the aggregating action and the adsorbing action. % By weight.

The artificial zeolites are Ca type and Mg type.
It is preferable to use artificial zeolites of the type, Fe type, etc. because of their excellent safety against living things and natural environments. In particular, when the aggregate obtained by the aggregating agent of the present invention is used as a valuable resource for soil such as fertilizer, these types are also advantageous in that the valuable material is excellent in safety for plant growth in soil. Artificial zeolites are preferred.

These artificial zeolites can be used alone or in combination of two or more when used.
For example, Ca-type artificial zeolite, Mg-type artificial zeolite, and Fe-type artificial zeolite may be used alone, respectively, or Ca-type and Mg-type composite artificial zeolite, Ca-type and Fe-type composite artificial zeolite, and Ca-type artificial zeolite. And Mg type and F
It may be used in combination such as e-type composite artificial zeolite. The type of such artificial zeolite is appropriately selected according to the intended use of the valuable material to be converted by the coagulant of the present invention. For example, when the flocculant of the present invention is used as a valuable resource for soil, it is appropriately selected depending on the condition of the soil.

Further, as the artificial zeolite, it is preferable to use one obtained by converting industrial waste such as coal ash because it can further contribute to the reduction of the amount of industrial waste. Specific examples thereof include an artificial zeolite obtained by the method for producing an artificial zeolite disclosed in Japanese Patent Laid-Open No. 2000-1311.

Examples of the coagulating component of the component (b) used in the present invention include water-soluble aluminum salts and / or polymer organic compounds. In particular, it is preferable to use both a water-soluble aluminum salt and a high molecular weight organic compound, because the formation of aggregates can be promoted by the coagulation action.

The content of the water-soluble aluminum salt in the coagulant is preferably 20 to 40% by weight, more preferably 23 to 38% by weight, from the viewpoint of improving the coagulation action.

As the water-soluble aluminum salt, for example,
Preferable examples include aluminum sulfate and sodium aluminate.

Further, the content of the high molecular weight organic compound is preferably 1 to 5% by weight, more preferably 1 to 4% by weight from the viewpoint of improving the coagulation action.

Examples of the high molecular weight organic compound include sodium polyacrylate, polyacrylamide, polyethyleneamine, starch, gelatin, sodium alginate and the like, and sodium polyacrylate, polyacrylamide and polyethyleneamine are particularly preferable. .

Examples of the coprecipitated component (c) used in the present invention include calcium sulfate and / or clays. In particular, it is preferable to use both calcium sulfate and clays in that the formation of aggregates can be promoted by the coprecipitation action.

The content of calcium sulfate in the coagulant is preferably 10 to 40% by weight, more preferably 10 to 34% by weight from the viewpoint of improving the coprecipitation effect.

On the other hand, the content of the clay is preferably 5 to 40% by weight, more preferably 6 to 33% by weight in the coagulant, from the viewpoint of improving the coprecipitation effect.

Examples of the clays include kaolin, talc, bentonite and acid clay, and kaolin, talc and bentonite are particularly preferable.

As long as the coagulant of the present invention does not substantially contain a chlorine component, in addition to the components (a), (b) and (c) described above, charge neutralization of active silicon dioxide or the like may be carried out if necessary. Agents and the like can be added.

The flocculant of the present invention can be prepared, for example, by mixing the above-mentioned components in the form of powder and mixing them.

In the preparation of the flocculant of the present invention, all the powdery raw materials are used as much as possible in that the flocculation rate can be increased and the amount of the flocculant added to the food washing wastewater can be minimized. It is preferable that the particle size is small, and the average particle size is 100 μm or less. Above all,
(B) The particle size of the high molecular weight organic compound, which is one of the coagulation components, is particularly preferably small, and the average particle size is about 50.
Adjusted to micron meter. The average particle size can be adjusted by
It can be performed using a crusher or the like.

When preparing the flocculant of the present invention,
It is preferable that each raw material is sufficiently dried, and the water content of each raw material is set to 10% by weight or less. This is because if moisture is absorbed, a chemical reaction may occur between the raw materials blended as the aggregating agent and the quality may change. In addition, even if the raw material has a high water content,
Before the coagulant is prepared, it can be used after being dried in advance with hot air or the like to have a desired water content.

Further, when preparing the flocculant of the present invention, it is preferable to uniformly mix the respective raw materials, for example,
A V-type mixer or the like can be used for uniform mixing. When mixing, if the difference in specific gravity between the raw materials is large, uniform mixing may be difficult, so it is desirable to appropriately set the mixing method and mixing time. As a mixer, V
A mixer other than the mold mixer may be used. Further, confirmation of uniform mixing can be carried out by a coagulation test or the like under certain conditions.

The flocculant of the present invention is used for the treatment of food waste water, and specifically, cut vegetables such as rice, soybean, seaweed, sprouts, and gabets, millet, coffee beans, oysters. It can be used for the treatment of wastewater discharged when washing etc.

The coagulant of the present invention has recently been applied as a coagulant for treating waste water of washing rice to waste water discharged during washing of rice (rice washing waste water, that is, rice polishing juice). Contributes to the improvement of the environmental deterioration associated with the industrialization of non-washed rice, and by the dehydration / drying treatment of the agglomerates including nuka,
It is preferable in that it can be converted into valuable substances such as fertilizers rich in nitrogen and phosphorus. Moreover, the flocculant of the present invention can be mainly used in the non-washed rice manufacturing industry, the bento manufacturing industry, the eating and drinking business such as a cafeteria and a restaurant, and the restaurant business.

According to the coagulant of the present invention, due to its purifying action, it is possible to reduce the concentration of SS, BOD substances, nitrogen, phosphorus, etc. in the washing wastewater of foods to make it transparent water.

According to the coagulant of the present invention, as described above, the coagulant itself is highly safe against the natural environment such as organisms and soil, and the target wastewater is food such as sharpening juice of rice. Combined with the fact that it is a washing wastewater, it is possible to obtain highly safe valuable substances that are not harmful to living organisms and the natural environment, such as fertilizers, compost ripening accelerators, culture solution additives for hydroponic cultivation, etc. . Among them, it is particularly useful as a valuable resource for soil such as fertilizer because it can utilize the fertilizing ability and water retaining ability of the artificial zeolite blended in the flocculant of the present invention.

The aggregating agent of the present invention can be added to the washing wastewater of food to form an agglomerate, and can be dehydrated and dried to form a valuable product.
A specific example of the method for producing this valuable material is as follows.

That is, the aggregating agent of the present invention is added in an amount of preferably 0.1 to 0.4 parts by weight to 100 parts by weight of food washing wastewater, and the mixture is stirred. Then, after confirming that the aggregate is separated from the supernatant water and settled, the supernatant water is discarded and the precipitated aggregate is taken out. After the aggregate is collected with a cloth bag or the like, the moisture content of the aggregate is preferably 30.
It is dehydrated by a desired dehydrating means such as a centrifuge so as to have a concentration of -40% by weight. Then, the dehydrated agglomerate is formed into a desired form, and further preferably 100 to 2 in a hot air drying oven or the like.
Dry at a temperature of 50 ° C. and form as a valuable.

In particular, when the rice washing wastewater is used as the food washing wastewater, the agglomerates dehydrated to a desired water content are mixed with rice bran, preferably in an amount of 25 to 45% by weight, to obtain a mixed powder, which is pelletized. After granulating into a shape or the like, it is dried. As this rice bran, one prepared at the time of rice polishing can be used separately from the above-mentioned waste water for washing rice. The water content of rice bran is preferably 10 to 25% by weight. In order to reduce the starch quality as much as possible and increase the proportion of phosphorus and nitrogen that are nutrients of the soil, and to enhance the effect as a valuable resource for soil such as fertilizer, the above mixture consisting of dehydrated aggregate and rice bran. It is further preferable to add a fermenting enzyme to the powder and perform a fermentation treatment for about 2 days to form a fertilizer. In this way, valuable resources for soil such as useful fertilizers having desired phosphorus content and nitrogen content can be formed. In addition, regarding the point which is not described in detail in the method in the case of using this waste water for washing rice, the above-mentioned method for producing a valuable resource is appropriately applied.

It is preferable to use the flocculating agent of the present invention and use the flocculating treatment device described below, in order to obtain a valuable resource having sufficient nutrients and excellent properties, particularly a fertilizer.
That is, keep the coagulant to the smallest possible amount,
Moreover, an apparatus having a structure capable of collecting the aggregate and drying it as soon as possible so that the aggregate does not decompose is preferable. Specifically, as shown in FIG. 1, a coagulant feeding unit 1 for finely sprinkling and feeding a coagulant, a stirring unit 2 whose rotation speed can be adjusted and whose rotation direction is reversible, and an apparatus bottom portion. A coagulation treatment device 10 including the located agglomerate recovery part 3, a wastewater supply line a connected to the upper part of the device, and a supernatant water discharge line b connected to the middle part of the device is suitable as an example.

In the aggregating apparatus 10, the aggregating agent feeding section 1 can spray and feed the aggregating agent into the food washing wastewater supplied from the wastewater supply line a and stored therein with the minimum addition amount. Further, the stirring unit 2 can quickly complete the aggregation. Further, the agglomerate collection unit 3 can facilitate the collection of the agglomerates in the agglomerate collection bag 4 and the like, and can avoid the inclusion of the agglomerates in the supernatant water. The supernatant water after coagulation is discharged from the supernatant water discharge line b. The aggregating apparatus 10 is of a so-called batch type, which is intermittent, but may be of a continuous type.

By using the above-described manufacturing method and aggregating treatment apparatus, it is possible to obtain a particularly useful valuable material such as fertilizer.

[0042]

EXAMPLES The present invention will be described in more detail below with reference to examples. The present invention is not limited to these examples.

[Examples (1) to (3)] The aggregating agent of each Example having the composition shown in Table 1 (% represents% by weight) was prepared by the preparation method described below. The artificial zeolites in Table 1 were converted by heat-treating coal ash, which is an industrial waste, as a raw material in an alkaline aqueous solution.
The details of the process are as follows. That is, 1 kilogram of coal ash and 3 liters of 3N caustic soda were put into an autoclave with an internal volume of 10 liters, and the mixture was heated at 130 ° C. for 3 hours.
After holding for a period of time, cooling, dehydration by a centrifuge, and washing with water were carried out to obtain 1 kg of Na-type artificial zeolite. Then, by treating in an aqueous solution of calcium chloride, magnesium chloride, and iron chloride, Ca-type, Mg-type, and Fe-type artificial zeolites were obtained, respectively.

[Preparation Method of Coagulant] As each raw material of the coagulant, a powder having an average particle diameter of 100 μm or less was used.
However, only the high molecular weight organic compound was used as a powdery substance having an average particle size adjusted to about 50 μm. The average particle size was adjusted using a pulverizer as needed. Further, as each raw material, one having a water content of 10% by weight or less was used. The water content was adjusted by hot air drying as needed. These raw materials were uniformly mixed with a V-type mixer to prepare an aggregating agent (powder).

[Preparation of Rice Washing Wastewater] In this example, rice washing wastewater was prepared using a dedicated rice washing apparatus. Rice washing equipment
The structure consists of a stirring tank for rice and water, a continuous water supply device, an overflow port for waste water of washing rice, and a tank for receiving waste water of washing rice. First, 5 kg of rice (brand: Akita Komachi) was put in a stirring tank, and stirring was started while gradually adding room temperature (about 15 ° C.) water to the stirring tank. The waste water of rice washing overflowed when it exceeded a certain amount in the stirring tank and was stored in the receiving tank of the waste water of rice washing. The amount of water required for washing rice was 35 liters. The time required for washing rice during this period was 5 minutes. Finally, all the waste water of washing rice was collected in the receiving tank of the waste water of washing rice. With the above method,
A rice washing waste liquid was prepared. In addition, this rice washing wastewater (before coagulation treatment)
When the respective concentrations of SS and BOD of
SS ... 1600 mg / L, BOD ... 650 mg / L.

<Agglomeration test> In 1 L of the obtained washing water of the rice,
2 g of the flocculant of Example (1) was added. Further, regarding each of the coagulants of Examples (2) and (3), Example (1)
In the same manner as above, 2 g was added to each 1 L of the washed rice liquor. At this time, the time from the addition of the aggregating agent to the start of aggregation of the components in the waste liquid was examined. Further, the transparency of the supernatant water after completion of aggregation was visually evaluated. Furthermore, the concentration of each of SS and BOD in the supernatant water after completion of aggregation (m
g / L). The results are shown in Table 1. Incidentally, the start of aggregation means the start of the formation of small aggregates (flocs). On the other hand, when the aggregation is completed, it means when the waste liquid is completely separated into the supernatant water and the aggregate.

[0047]

[Table 1]

<Formation of valuables> 5 pieces of 750 grams of rice
After polishing with 1 liter of water, 10 g of the flocculant of the present invention (flocculant of Example (1)) was added to the washed rice waste water, and after stirring for about 60 seconds, the flocculate separated from the supernatant water and settled. The sedimented agglomerate contains the components of the aggregating agent, rice bran from rice and starch. After discarding the supernatant water and taking out the sedimented aggregate, a slightly coarse cloth bag was collected and then dehydrated by a centrifugal separator. The water content of the aggregate at this point was about 35%. Next, 30 to 40% of rice bran having a water content of about 15% obtained during rice polishing was mixed with the agglomerate. Next, the mixed powder was granulated into pellets or the like and further dried in a hot air drying oven at a temperature of about 150 ° C. to form pellets. As a result of analysis, this pellet has a phosphorus content of 1.5%,
It was found that the nitrogen content was 1.6%, and it proved to have sufficient performance as a valuable resource, especially as a fertilizer.

[0049]

EFFECTS OF THE INVENTION According to the present invention, it is possible to prevent water pollution, reduce equipment and running costs, reduce industrial waste, and convert waste into valuable resources. A flocculant for use can be provided.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an aggregating treatment apparatus for forming a valuable substance with the aggregating agent for treating food waste water of the present invention.

[Explanation of symbols]

10 ... Aggregation processing device, 1 ... Coagulant injection part, 2 ... Stirring part,
3 ... Aggregate collection part, 4 ... Aggregate collection bag, a ... Waste water supply line, b ... Supernatant water discharge line

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C02F 1/28 C02F 1/28 Z 1/52 1/52 C 1/56 1/56 C F term (reference) ) 4D015 BA04 BA05 BA11 BA17 BA19 BB08 BB12 CA04 DA02 DA05 DA08 DA25 DA32 DA35 DB01 DB03 DB12 DB24 DB33 DB35 DC04 EA06 EA32 4D024 AA04 AB00 BA07 BB01 BC04 CA01 CA06 DA10 DB12 DB21 4G066 AA62B BA09 CA02 DA08

Claims (8)

[Claims] 1. A coagulant containing at least (a) an ion exchange / adsorption component, (b) a coagulation component, and (c) a coprecipitation component, wherein an artificial zeolite is blended as the (a) ion exchange / adsorption component. And a coagulant for treating food wastewater, which is substantially free of chlorine. 2. The blending amount of the artificial zeolite is 10 to 10.
The aggregating agent for treating food wastewater according to claim 1, which is 40% by weight. 3. The cleaning wastewater treatment of foods according to claim 1, wherein the artificial zeolite is one or more artificial zeolites selected from the group consisting of Ca type, Mg type and Fe type.
The aggregating agent described. 4. The aggregating agent for cleaning food wastewater according to claim 1, wherein the coagulating component (b) is a water-soluble aluminum salt and / or a high molecular weight organic compound. 5. The content of the water-soluble aluminum salt is 2
The aggregating agent for cleaning food wastewater according to claim 4, wherein the aggregating agent is 0 to 40% by weight, and the content of the high molecular weight organic compound is 1 to 5% by weight. 6. The flocculant for treating food wastewater according to claim 1, wherein the coprecipitating component (c) is calcium sulfate and / or clay. 7. The calcium sulfate content is 10 to 4
0% by weight, and the clay content is 5 to 40% by weight
The aggregating agent for treating food wastewater according to claim 6, which is 8. The aggregating agent for treating washing wastewater of food according to any one of claims 1 to 7, which is for treating washing wastewater of rice.