JPS61209088A - Concentrated bacteria carrier for treating organic waste water and its preparation - Google Patents

Abstract

PURPOSE:To obtain a bacteria carrier having high purification activity, by forming a granular substance from bacteria useful for the treatment of org. waste water and a substance digested by bacteria and mixing said granular substance with a monomer forming a polymer substance to perform polymerization. CONSTITUTION:A granular substance consisting of bacteria useful for the treatment of org. waste water, carageenan, salts such as potassium chloride, a substance digested or solubilized by bacteria and calcium carbonate is mixed with and dispersed in a monomer forming a polymer substance. Then, a polymerization promoter and a polymerization initiator are added to the resulting mixture under stirring to perform polymerization. After polymerized and allowed to stand and solidify, it is molded into a granular form to obtain a granular bacteria carrier. During the treatment of waste water by this carrier, the digestible substance and carageenan are decomposed and removed by bacteria to form a carrier wherein grid spaces are wide and bacteria are held in fine pores at high density. Therefore, purification activity is high and the apparatus can be made compact by using this carrier.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a concentrated microbial carrier capable of efficiently carrying out biological treatment of organic wastewater and a method for producing the same.

[Conventional technology]

As is well known, in order to preserve microorganisms for wastewater treatment, (
There are methods such as (a) attaching it to a carrier, (b) incorporating it into a polymeric substance that constitutes the carrier, and (c) trapping it in the pores of the carrier, and it is difficult to use methods other than these.

Recently, as the method (b) above, a method of polymerizing and molding a monomer with microorganisms mixed therein has been studied. This method has the following advantages: (+) It is easy to maintain a specific microorganism as a dominant species, (fi) It is difficult to cause washout from the reactor, and (0) it is easy to maintain a high concentration of microorganisms.

(Problems to be solved by the invention) Since research into the above-mentioned method of incorporating microorganisms into a polymeric substance has only recently begun, there are a number of problems in practical use, and it is difficult to solve them. is necessary.

(a) Monomers used during polymerization of polymeric substances,
Various compounds such as a crosslinking agent, a polymerization initiator, and a polymerization accelerator cause phytotoxicity to the microorganisms to which they are immobilized, impair purification activity, and sometimes cause deactivation.

(b) Since the space within the lattice of the polymeric substance is insufficient, the ability to diffuse and permeate gas and aqueous solution into the carrier is small. In other words, the effective coefficient indicated by the oxygen absorption rate when the compact is crushed is small.

(C) Due to the above (a) and (b), highly efficient purification activity cannot be obtained.

This invention was made in view of the above circumstances, and the lattice space is wide, allowing for breathability, water permeability, and gas permeability.

The permeation and diffusion of various dissolved components such as ions, organic substances, and inorganic salts are good, and the various chemicals used in forming molecular substances do not damage microorganisms, and the purification activity per unit microorganism holding carrier is large. Therefore, it is an object of the present invention to provide a microbial carrier and a method for producing the same that can contribute to downsizing of wastewater treatment equipment and reducing initial costs.

(Means for Solving the Problems) The present invention provides that granular materials containing at least microorganisms effective for organic wastewater treatment and substances that are assimilated or made water-soluble by the microorganisms are decomposed by the microorganisms. It is a microbial carrier that is mixed and dispersed in a molded polymeric material that is not used to treat organic wastewater, and forms granules from at least microorganisms that are effective in treating organic wastewater and substances that are assimilated or made water-soluble by these microorganisms. This is a method for producing a microbial carrier, in which the monomer is mixed and dispersed in a monomer that forms a polymeric substance that cannot be decomposed by the microorganism, and the monomer is polymerized and molded to obtain a microbial carrier.

Examples of substances that are assimilated, that is, at least partially converted into living cells, by the microorganisms include corn steep liquor and waste molasses, and substances that are made water-soluble by the microorganisms include, for example, limestone and molasses. There are substances such as sand and shells that contain calcium carbonate as a main component.

[Effect]

The substances assimilated by the above-mentioned microorganisms are assimilated by the progress of microbial reactions regardless of whether they are anaerobic or aerobic. In other words, the above substances are converted into carbon dioxide, water, methane, nitrogen, hydrogen, water-soluble intermediate decomposition compounds, etc. depending on the microorganism.
Some of them are transformed into living cells. At the same time, if substances such as limestone are present in the surrounding area and the organic wastewater contains nitrogen valves in the form of organic or ammonia nitrogen, it will be nitrified to nitrate nitrogen in an aerobic reaction. Due to the pH drop within the particles at this time, the water-insoluble substances and solids become water-soluble and become easily diffused into water. On the other hand, in anaerobic reactions, intraparticle p due to acid fermentation
As t+ decreases, the carbonic acid cacalcinium-based compound similarly decomposes and dissolves. Therefore, substances other than microorganisms in particulate matter dispersed in polymeric materials are absorbed by microbial organisms, but they are dissolved in water, so they are dissolved in relatively large pores (lattices) in polymeric materials. A large number of internal spaces (inner spaces) are formed, and microorganisms tend to be retained at a high density in these pores.

Therefore, the effect of this microbial carrier in wastewater treatment is that, for example, in an aerobic reaction, (the amount of microorganisms that can be held within the Al polymer material lattice increases, and (B) the polymer molded carrier) (C) Diffusion of pollutants to be decomposed into the same interior becomes easier, and (D) As a result, neither oxygen diffusion rate-limiting nor pollutant diffusion rate-limiting occurs deep within the carrier. In other words, the excellent advantage that the removal reaction becomes rate-limiting can be obtained.

In this way, in the conventional biofilm method or the method in which microorganisms are included in a polymeric substance, the rate is often either oxygen diffusion limited or pollutant diffusion limited.
By adding J to the microorganism carrier of the present invention, the removal reaction can be made rate-limiting, making it possible to effectively contribute to purification deep into the carrier, and together with an increase in the number of microorganisms G, the purification per unit volume can be reduced. It becomes possible to increase efficiency.

The same thing can be said about anaerobic reactions, except for the problem of oxygen diffusion. In anaerobic reactions, various gas components (methane, carbon dioxide, hydrogen, etc.) generated can be quickly diffused and removed from within the polymeric material, thereby promoting the diffusion of contaminants within the polymeric material. ,
It becomes possible to accelerate the removal reaction.

Furthermore, according to the above configuration, it is possible to coat microorganisms, so that they are not adversely affected by monomers and chemicals added during polymerization, and as a result, there is no loss of microorganisms.
It becomes possible to maintain microorganisms in a highly concentrated state. Therefore, if a granular material is formed by adding a highly coated assimilable substance such as carrageenan, the above effects can be reliably obtained.

〔Example〕

Microorganisms 5,000 to 100,000 I! g/J of an aqueous solution, add 1 to 10 wt% of carrageenan, potassium chloride, organic matter assimilated by microorganisms, and, if necessary, about 2 to 8 wt% of a calcium carbonate-based compound, and dissolve this at around 40°C. Mix and suspend.

A part of this mixed suspension was added to 1 to 1Qwt% potassium chloride (
The mixture was poured into an aqueous solution (0°C to 15°C) of ammonium chloride to form a gel, and the gel was filtered through a filter cloth. (I
) To this gel (granular material), 31 wt% water, 9 wt% acrylamide, a crosslinking agent 1 a polymerization accelerator 2 a polymerization initiator were added and stirred, and this was left to solidify, and then molded into particles to form particulate microorganisms. A carrier was obtained.

- On the other hand, the remainder of the mixed suspension was allowed to cool and solidify, and after solidification, it was finely crushed or formed into particles. The obtained granules were incorporated into an acrylamide molded body by the same operation as in (I) above to obtain particulate microbial carriers.

While each microbial carrier obtained as described above is used for biological treatment of wastewater, assimilable substances are removed in a fairly short period of time (1 to 2 days), and carrageenan is gradually decomposed by microorganisms. Ta. The resulting internal lattice spaces (pores) had a large volume, which facilitated the diffusion of gases and organic substances, resulting in a large effective coefficient.

In addition, when treating nitrogen-containing organic wastewater, calcium carbonate compounds were dissolved in 3 days to 2 months due to a decrease in pH due to nitrification reaction, contributing to an increase in interstitial voids.

As a result, while the effectiveness coefficient when only acrylamide was used was about 40 to 55%, in the case of the present invention, it was found to be 60 to 85%, a remarkable improvement.

〔Effect of the invention〕

As explained above, according to the present invention, the lattice space is wide, and the air permeability, water permeability, gas, ion, organic matter, etc.
Penetration of various dissolved components such as inorganic salts.

It has good diffusion, and the various chemicals used when forming polymeric substances do not damage microorganisms, and the purification activity per unit microorganism holding carrier is large, which makes wastewater treatment equipment more compact and reduces initial costs. Concentrated microbial carriers for organic wastewater treatment can be easily produced.

Claims (5)

[Claims] (1) A granular material containing at least a microorganism effective for organic wastewater treatment and a substance assimilated or made water-soluble by the microorganism is mixed and dispersed in a molded polymer material that is not decomposed by the microorganism. A concentrated microbial carrier for organic wastewater treatment, which is characterized by the following properties: (2) The granular material mainly contains microorganisms effective for organic wastewater treatment, carrageenan, salts such as potassium chloride, water, substances assimilated or made water-soluble by the microorganisms, and/or calcium carbonate. The concentrated microbial carrier for organic wastewater treatment according to claim 1, which is a gel-like substance composed of powder and granules as a component. (3) Particulate matter is formed from at least a microorganism that is effective in treating organic wastewater and a substance that is assimilated or made water-soluble by the microorganism, and the particulate matter is contained in a monomer that forms a polymeric substance that cannot be decomposed by the microorganism. 1. A method for producing a concentrated microbial carrier for organic wastewater treatment, which comprises mixing and dispersing monomers, polymerizing and molding the monomer, and obtaining a concentrated microbial carrier. (4) Microorganisms effective for organic wastewater treatment, carrageenan, and substances assimilated or made water-soluble by the microorganisms;
and/or a powder or granule mainly composed of calcium carbonate at about 40°C, and the mixture is poured into salt-containing water and gelled to obtain a granule. A method for producing a concentrated microbial carrier for organic wastewater treatment according to scope 3. (5) Powder whose main components are microorganisms effective for organic wastewater treatment, carrageenan, salts such as potassium chloride, water, substances assimilated or made water-soluble by the microorganisms, and/or calcium carbonate. Mix with granules at about 40℃,
4. The method for producing a concentrated microbial carrier for treating organic wastewater according to claim 3, wherein after mixing, the mixture is left to cool and solidify, and then crushed into granules to obtain a granular material.