JPH01224012A - Treatment of waste water - Google Patents

Abstract

PURPOSE:To enhance a solid-liq. separation effect on the waste water having a high content of org. matter with a simple method by treating the waste water, etc., from a food production process with flocculating yeast and a flocculant. CONSTITUTION:Waste water from a food production process is treated with flocculating yeast, and then added with a flocculant. Alternatively, the yeast and flocculant can be simultaneously added. Hansenula-anomala (The Microbiological Research Institute's report No.7671) can be exemplified as the yeast. The waste water treatment by the yeast is preferably carried out at pH3-8 and 10-36 deg.C. A cationic high molecular flocculant, an anionic high molecular flocculant, etc., are appropriately used as the flocculant, and the amt. of the flocculant to be added is appropriately controlled to 0.02-8% based on the solid matter.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for treating wastewater, and more specifically, the present invention relates to a method for treating wastewater, and more specifically, for rapidly treating various kinds of wastewater such as food manufacturing wastewater using a specific yeast and a flocculant. It is about the method.

Therefore, the present invention is important not only in the field of wastewater treatment technology but also in the field of pollution prevention technology, and the sludge produced as a by-product from wastewater treated by the present invention has a particularly high protein content and is highly edible. Therefore, the present invention is also of great use in the technical field of feed.

(Prior art) Wastewater, especially food manufacturing wastewater, has a high BOD value and not only cannot be directly discharged into rivers, but also has a high load when treated with treatment equipment, so it cannot be treated quickly. Can not.

In order to solve this problem and efficiently treat food manufacturing wastewater with high concentrations and rapid load fluctuations, a method of removing organic matter contained in wastewater using flocculant yeasts such as Hansenula anomala has been proposed. (Japanese Unexamined Patent Publication No. 61-1531)
Publication No. 97).

(Problems to be Solved by the Invention) However, although the above method removes organic matter from wastewater, it causes the drawback that other organic matter is newly formed and further treatment is required. be done.

Such secondary organic substances are themselves bulky and difficult to filter or precipitate, making solid-liquid separation very difficult. Moreover, even if it is attempted to subject this to activated sludge treatment, which is often used in wastewater treatment, the load on the equipment will increase significantly, making it unsuitable for industrial large-scale treatment. Furthermore, when activated sludge treatment is performed, it is difficult to use the generated solid precipitate for other purposes, and in particular, from safety and food hygiene considerations, it is completely impossible to use it as feed.

(Means for Solving the Problems) The present invention has been made to solve the above-mentioned drawbacks all at once.

That is, the present invention further improves the above-mentioned wastewater treatment method using flocculating yeast, and develops an industrial method that can quickly and efficiently perform solid-liquid separation of wastewater using a simple method that does not require skill. It was done for the purpose of

Therefore, we first investigated the main body of the organic matter that was secondarily produced by the flocculating yeast treatment, and the results of various studies.

It was found that the organic matter was mainly composed of yeast that had grown using the organic matter in the wastewater.

We then conducted research from various angles on the best way to further process this organic matter. In other words, various treatments have been tried, such as allowing the bacterial cells to be digested by other microorganisms, mechanically crushing them, and chemically treating them.

None were successful.

As a result of further research, we focused on food additives and selected chitosan-based cationic polymer flocculants in particular.
When this was added to wastewater after yeast treatment, secondary organic matter coagulated in an extremely short period of time, making solid-liquid separation extremely easy. We obtained extremely useful new knowledge that not only is the cake not toxic, but about half of its ingredients are protein, and it can be used as feed. The present invention was completed as a result of further studies based on this new knowledge.

In the present invention, flocculating yeast is used,
As the flocculating yeast, yeast belonging to any genus can be used as long as it is a type of yeast that can remove organic matter contained in wastewater; an example is Hansenul.
A anomala is mentioned. The yeast has been deposited with the National Institute of Fine Arts and Technology as No. 7671, and its mycological properties are detailed in JP-A-61-153197.

The conditions for wastewater treatment using flocculating yeast include the pH of the wastewater.
pH is within a wide range of 3 to 8, preferably 5 or less to prevent contamination by other microorganisms, and the treatment temperature is 10 to 3.
The temperature range is 6°C, preferably 15-30'C. Furthermore,
Add 20% sodium hypochlorite or sulfite each to wastewater.
If it is added every day or every other day at a concentration of ~30 ppm or 30 to 40 ppm, other microbial contamination can be more effectively prevented.

In addition to treating the flocculating yeast as it is, it is also possible to treat wastewater more effectively by attaching it to the surface of a carrier such as activated carbon or glass peas and causing it to flocculate depending on the case.

The material of the treatment tank is not particularly limited, but acid-resistant materials are desirable. The treatment tank is aerated and stirred using an air pump, etc.
In some cases, stirring with a stirrer can improve the aeration effect.

In the case of wastewater containing low concentrations of organic matter, it is possible to bring the water quality below the wastewater standards only by treatment with flocculating yeast.

However, especially in wastewater containing high concentrations of organic matter, or when even low concentrations of organic matter are treated for a long time, new organic matter may be formed secondarily (as mentioned above,
The main body of the activated sludge was confirmed to be organic matter mainly composed of flocculating yeast), but even if we tried to treat it with activated sludge, the load would increase and a vast amount of equipment would be required. cannot be removed industrially.

The present invention has succeeded in solving this problem by adopting a completely new configuration of using a flocculant.

As flocculants, all types of substances can be widely used as long as they are capable of flocculating suspended matter in wastewater.
For example, various polymer flocculants such as cationic polymer flocculants and anionic polymer flocculants are suitable. The amount added varies depending on the type of flocculant, but is approximately 0.02% to 8% based on the solid matter. These flocculants may be used for cars or several types may be used in combination, and there are no particular limitations.

In addition to being added to wastewater after treatment with flocculating yeast, flocculants may also be added at the same time as yeast treatment, and there are no particular restrictions on the timing of their addition. suitable for the purpose. Moreover,
It was also discovered that the flocculant treatment and the yeast treatment are compatible without interfering with each other, which is extremely suitable for industrialization. Therefore, the timing and amount of addition of the flocculant,
The number of additions, etc. can be freely selected.

Among flocculants, when non-toxic flocculants used as food additives, such as polyacrylic acid-based flocculants and especially chitosan-based cationic polymer flocculants, are used, the collected sludge is rich in protein. Not only is it a natural substance, but it is also easily digested and absorbed within the animal body, so it can be used directly as feed for livestock, poultry, fish, etc. without drying or drying, and it can also be widely used as a raw material for feed. . Of course, it can be used as fertilizer.

The wastewater treated liquid treated in this manner can be easily dehydrated by sedimentation, filtration, centrifugation, a filter press, a filter cloth running type dehydrator, etc., and subjected to solid-liquid separation. The solid matter, or sludge, separated here can be used for the above-mentioned purposes, while the liquid can be directly discharged into rivers as is, or if necessary, it can be further treated with secondary treatment such as activated sludge treatment. Good too.

Moreover, in this case, the load on the equipment can be greatly reduced, and the need for adding more equipment can be avoided, which is extremely economical, and in some cases, it is even possible to reduce the number of equipment.

Examples of the present invention will be described below.

Example 1 The mash produced by saccharifying beer barley is filtered, and the by-product (beer lees) is dehydrated. The liquid that comes off at that time (beer lees) is as follows It had a similar composition.

Bearing shaft filtrate raw water composition (SS: overall value SUP: soluble substance value) The above-mentioned bearing shaft filtrate was subjected to yeast treatment for 20 days according to the following specifications.

Yeast tank: IQ jar fermenter Treatment time: 4aHr Batch treatment (500mR/d-
Batch) PH: 4.6 to 4.8 Automatically controlled temperature: 35°C Automatically controlled ventilation: 1.0VVII Stirring: 700 rpm+m Antifoaming agent: S-4000 or CC-118 Analysis was performed by sampling the treated liquid and using the usual method. Measurements were carried out on SS and SUP.

The results for 20 samples over 20 days were summarized as follows.

Umbrella C0D (SS) 20,840ppm - average removal rate 35% (SUP) 3,700ppm = average removal rate 65%wa B OD (SS) 17,900p
pm-average removal rate 60% (SUP) 2,730p
p-1 average removal rate 84% heavy viscosity raw water 200
cp→treated water 70cp Umbrella yeast tank microorganisms flocculating yeast:
+++ Wild yeast: + Bacteria: ÷ The yeast-treated water thus obtained was flocculated under the following conditions, and suction filtration was performed using N(1101 filter paper. (Numbers against) ■ Perform yeast-treated water without chemicals.

■Yeast-treated water + inorganic flocculant PAC (2%) + anionic polymer flocculant A-110 (0.2%) ■Yeast-treated water buffalo cationic polymer flocculant 0X-1005 (2%) + anionic polymer flocculant 0X-1005 (2%) + anionic polymer flocculant A-110 (0.2%) Molecular flocculant 0A-5 (0.2%) As a result, the filterability tends to deteriorate in the order of ■ → ■ → ■, and ■ and ■
The flocculation state was good.

The BOD (SLIP) of the filtrate in (2) was 2,500 ppm.

As is clear from the above results, it was found that excellent solid-liquid separation was achieved by the combined use of flocculant yeast and flocculant.

Example 2 The yeast-treated water obtained in the above example was flocculated under the conditions of Tests I to ① described below, and dehydrated under the following dehydration conditions.

Dehydration tester (Maru-1) Squeezing filter press Filtration area: 0.045M Cake capacity: 0.45SR Cake chamber: 1 chamber (cake thickness 20mm) Test filter cloth: Polyester No. 7032 Air permeability 10cc
/see Filtered pressure crab 2.5kg/a+f Pressed pressure crab 5.0kg/a (Test 1. Yeast treated water (SS 4%) Ten diatomaceous earth #900
(1% based on the slurry liquid).

Skewer slurry SS concentration approximately 5% Testro. Yeast treated water (SS 4%) is used without chemicals.

Concentration of slurry SS: approx. 4% Test ■: Perform yeast-treated water (SS 4%) by centrifuging and concentrating without adding chemicals.

$Slurry SS concentration approx. 7.9% Test■, Yeast treated water (SS 4%) Ten cationic polymer flocculant 0X-10O3 (2%) + Anionic polymer flocculant 0A-5 (at 0.2 phantom) conduct.

Umbrella slurry SS concentration: Approximately 4% (The polymer flocculant used in this chemical injection process is Orflock manufactured by Organo■, a cationic polymer flocculant 0X
-1OO3 (chitosan type) and anionic polymer flocculant 0X
-5 (polyacrylic acid type), both of which are used as food additives. ) The dehydration test data for each sample are summarized as follows, and the obtained results are shown in Figures 1 to 4.

Dehydration test data As is clear from these results, it was found that by performing yeast treatment, it was possible to reduce the viscosity of the shaft filtrate, which is the raw water to be treated, and further recover solid matter. Considering only the dehydration efficiency, it is recognized that the case where a concentrated slurry is dehydrated without chemical injection (DI) and the case where a slurry flocculated with a polymer flocculant is dehydrated (IV) are suitable.

However, the peelability of the cake from the filter cloth is (III)
Case (III) is bad, and case (III) requires centrifugation, but such processing is completely unsuitable for industrial large-scale processing from the cost and operational standpoint, and the system itself is It inherently has a fundamental and essential flaw.

Moreover, it is criticized that chemical injection treatment (IV) is better in terms of long-term stability of the treatment. In this case, the treatment can be carried out not only with a filter press but also with a filter cloth running type dehydrator, for example.

In addition, after drying and pulverizing the dehydrated cake collected here, component analysis revealed that T-N was 7.83% T-N in terms of dry matter.
-P was 1.15%.

Therefore, if the protein coefficient is 6.25, the crude protein is approximately 48
．． 9%, nearly half of which is protein. Therefore, by collecting sludge using a chitosan-based flocculant in yeast-treated water, it is possible to reduce the load on activated sludge treatment equipment, and at the same time, it is possible to effectively use the generated sludge for feed, etc. It is.

(Effects of the Invention) According to the present invention, by adopting for the first time a completely new structure of organic bonding between flocculant yeast and a flocculant, it is possible to effectively treat various industrial wastewater, domestic wastewater, sewage, etc. It has the remarkable effect that it can advantageously treat food manufacturing wastewater, which was impossible with conventional treatment techniques due to its high organic matter content.

According to the present invention, solid-liquid separation in wastewater is performed quickly and easily, so not only can the treatment be carried out in a short time, but the treatment equipment can also be simplified. The load on the process is reduced, making it an extremely outstanding industrial treatment method.

Furthermore, the by-product sludge can be used as feed material, which is effective in making effective use of sludge that was previously discarded, and in preventing secondary pollution such as decay of waste sludge.
It is also outstanding in this respect.

[Brief explanation of the drawing]

1 to 4 illustrate the dehydration results of Tests I to ① in Example 2. Agent Patent attorney 1) Parent male pressure + kg/aj) VP & cumulative amount (xl
o'm+)0 ψ
6f liquid 5 (XIO'ml) Pressure (kg/cd) σ liquid! Cumulative total (x+o
'＋＋Dro φ
6 pieces liquid tan (xlo'*l)

Claims (1)

[Claims] A wastewater treatment method characterized by treating food manufacturing wastewater, etc. using a combination of flocculant yeast and a flocculant.