JPS61287500A - Treatment of liquid containing organic substance - Google Patents

Abstract

PURPOSE:To efficiently utilize the residual pressure which has been discharged heretofore and to reduce electric power by charging a fluidizable carrier deposited with bacteria into a reaction vessel and returning the pressurized concd. liq. recovered from the concd. liq. side of a membrane separator to the reaction vessel. CONSTITUTION:A reaction vessel 1 and a membrane separator 3 are arranged in the order described, an org. substance-contg. liq. is introduced into the vessel 1 for a biochemical reaction and the treated liq. discharged from the vessel 1 is introduced under pressure into the separator 3 wherein low-molecular valuable materials are separated by a membrane into the permeated liq. side of the membrane. The org. substance-contg. liq. is thus treated. In the method, a fluidizable carrier deposited with bacteria is charged into the vessel 1 and the pressurized concd. liq. recovered from the concd. liq. side of the separator 3 is returned to the vessel 1. Namely, the pressure remaining on the concd. liq. side and which has been discharged heretofore without being reutilized can be utilized and the cost of power required for the formation of fluidized bodies can be reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for treating a liquid containing an organic substance, and more particularly, to a method for treating a liquid containing an organic substrate that can be converted into other valuable substances. It is.

[Prior Art] As an example of a method for treating a liquid containing a substrate that can be converted into other valuable substances, such as pulp waste liquid, there is a method in which organic substances contained in the waste liquid are decomposed by microorganisms. Are known. In this method, a means for separating valuable substances must be added because it is necessary to separate newly produced valuable substances from the mother liquor. However, these valuable substances are generally low-molecular liquid substances, and raw materials such as pulp waste liquid are high-molecular liquid or solid substances, so membrane separation techniques such as reverse osmosis and ultrafiltration are used as means for separating them. It is considered that its use is effective.

FIG. 2 is a flow explanatory diagram showing a conventional typical processing system A. In said system A, the raw material to be treated is led via line 5 to reaction vessel l. The raw materials include:
For example, a glucose-containing liquid obtained by saccharifying cellulose contained in pulp waste liquid is exemplified, and the case where the glucose-containing liquid is used as a raw material will be explained below. In reaction tank 1,
Since air is supplied through the pipe line 12 and the conditions are aerobic, the raw materials introduced into the reaction tank 1 are subjected to aerobic conditions by the yeast supported on the carrier (not shown) in the reaction tank 1. It is fermented and ethanol etc. are produced. The generated ethanol-containing liquid (containing unreacted glucose, etc.) is introduced into the water tank 2 through the pipe 6. Water whose flow rate is adjusted by a flow rate regulating valve 7 is supplied to the water tank 2, and the ethanol etc. produced in the reaction tank 1 are diluted with wood in the water tank 2, and valuable substances such as ethanol can be easily separated by membrane. It becomes a state. Ethanol or the like is drawn out under pressure from the water tank 2 by a high-pressure pump 8 and introduced into the concentrate side of the membrane separation device 3 via a pipe 9. The membrane separator 3 separates low molecular weight substances such as ethanol as a permeated liquid, and the permeated liquid is stored in a storage tank 4 via a pipe line 10. Further, in the membrane separator 3, the pressurized liquid on the concentrate side is taken out under atmospheric pressure via the waste water pipe 11,
Disposed of or subjected to other appropriate disposal with the residual pressure released.

[Problems to be Solved by the Invention] In the membrane separation technology described above, the liquid to be treated in the water tank 2 is introduced into the membrane separation device 3 in a pressurized state by the high-pressure pump 8, but the residual pressure after permeation is Currently, the retained concentrate is discarded without checking the residual pressure. Such membrane separation technology has traditionally been distinguished by being called reverse osmosis or ultrafiltration, but there is no essential difference between these names; If you understand from
At least qualitatively, they are exactly the same. However, since the reverse osmosis membrane method aims to separate low-molecular solutes from high-molecular substances, salts, etc., it has the characteristic of requiring extremely high pressure. It is recognized as particularly remarkable.

Furthermore, regarding the reaction tank 1, in the past, the floating method was the mainstream method for maintaining high concentration of bacterial cells in the reaction tank 1, but in the past, the carrier carrying the bacteria was fixed in the reaction tank 1. In recent years, the so-called fixed bed method of holding the carrier has developed, and in order to increase the chances of contact between the carrier and the raw material, the carrier is placed in a reaction tank 1.
So-called fluidized bed methods have been proposed.

Although this method has the advantage that the reaction in the reaction tank 1 can be carried out quickly compared to the conventional floating method or fixed bed method, etc., it requires a circulation pump (not shown) to flow the carrier in the reaction tank 1. etc. must be used as a power source,
A new problem arises in that equipment costs and energy costs are higher than in conventional methods.

The present invention was made in view of the above-mentioned current situation, and is an organic material that can reduce the power required up until now by effectively utilizing the residual pressure that was conventionally discarded without being utilized. The object of the present invention is to provide a method for treating a liquid containing a sexual substance.

[Means for Solving the Problems] According to the present invention, a reaction tank and a membrane separation device are arranged in the above described order, and an organic substance-containing liquid is introduced into the reaction tank to perform a biochemical reaction, 1; In a method for treating organic substances by introducing the reaction treated liquid taken out from the reaction tank under pressure into a separation device and separating low-molecular valuables into the permeate side with a membrane, The main feature is that a carrier carrying bacterial cells is charged in a fluidized manner, and the pressurized concentrated liquid recovered from the concentrated liquid side of the membrane separation device is returned to the reaction tank. .

[Action 1 Various techniques have been developed in the past, as shown in FIG. 2, that utilize reaction products produced by the action of bacterial cells on an organic substance-containing liquid. Although the basic configuration of the present invention is not particularly different from the conventional system A (Fig. 2), the inventors of the present invention aimed to reduce the power cost for driving circulation pumps, etc., which was previously abandoned. Based on this guideline, the present invention was completed after conducting various studies.

In the present invention, by adopting the above configuration,
It is now possible to effectively utilize the residual pressure on the concentrate side, which was previously unused and discarded, and it is also possible to reduce the power required to make the reaction tank a fluidized bed type. Ta.

Hereinafter, the present invention will be explained in more detail using FIG.

[Example] FIG. 1 is a flow explanatory diagram showing an example of an embodiment of the present invention. The basic configuration of the present system B is the same as that of the conventional system A, and corresponding parts are given the same reference numerals to avoid redundant explanation. What should be noted in FIG. 1 is that this system B is provided with a return path 15 for returning the pressurized liquid discharged from the concentrated liquid side of the membrane separation device 3 to the reaction tank 1. The return path 15 connects the concentrate side of the membrane separation device 3 and the reaction tank 1, and the pressurized liquid on the concentrate side is returned to the reaction tank 1 while maintaining residual pressure. This makes it possible to effectively utilize the residual pressure that was previously unused and wasted, and to separate the power source for the circulation pump, etc. that was required to form the fluidized bed in the reaction tank 1. There is no need to provide one, so it is possible to reduce power costs.

A flow rate adjustment valve 18 is interposed in the return path 15, and the flow rate of the pressurized liquid returned to the reaction tank l is controlled by this flow rate adjustment valve 18.
adjusted by. Further, a bypass pipe 17 branching from the return path 15 may be provided to supply pressurized liquid on the concentration side to the water tank 2. A flow rate adjustment valve 16 is interposed in the bypass pipe 17, and the water tank 2 is controlled by the flow rate adjustment valve 16.
The flow rate of the pressurized fluid returned to is adjusted. The bypass pipe 17 is provided for the purpose of increasing the linear velocity on the membrane surface of the membrane separator 3 to prevent solid content from adhering to the membrane surface, and is used to supply water from the water tank 2 to the membrane separator 3. The above objective is achieved by adjusting the amount of water.

- In the embodiment described above, the case was described in which a liquid containing glucose etc. after saccharification of pulp waste liquid was converted into an ethanol-containing liquid etc. However, according to the spirit of the present invention, when treating the pulp waste liquid of the present invention It can be suitably implemented not only when treating urban wastewater such as human waste, but also when treating urban wastewater such as human waste. Therefore, in the above-mentioned embodiment, the reaction tank 1 was described as one that performs an aerobic reaction, but it is also possible to configure the reaction tank 1 so that an anaerobic reaction is performed without providing the pipe line 12. Of course.

[Effects of the Invention] As described above, according to the present invention, it is possible to effectively utilize the pressure remaining on the concentrated liquid side, which was conventionally unused and discarded, and to reduce the pressure of one liter to form a fluidized bed. It became possible to reduce the power costs that were required in

[Brief explanation of drawings]

FIG. 1 is a flow explanatory diagram showing an example of an embodiment of the present invention,
FIG. 2 is a flow explanatory diagram showing a conventional typical processing system A.

Claims (1)

[Claims] A reaction tank and a membrane separation device are arranged in the stated order, an organic substance-containing liquid is introduced into the reaction tank to perform a biochemical reaction, and a reaction-treated liquid taken out from the reaction tank is transferred to the membrane separation device. In a method of treating an organic substance-containing liquid by introducing it under pressure and separating low-molecular-weight valuables into the permeate side through a membrane, a carrier carrying bacterial cells is charged into the reaction tank in a flowable manner. A method for treating an organic substance-containing liquid, characterized in that the pressurized concentrated liquid recovered from the concentrated liquid side of the membrane separation device is returned to the reaction tank.