JPH05123664A - Treatment of waste and waste water - Google Patents

Abstract

PURPOSE:To produce gaseous methane by utilizing waste discharged from each home as well as to smoothly collect and transport the waste. CONSTITUTION:Noncombustible solid matter is separated and removed from solid waste and the resulting combustible solid matter is crushed and mixed with waste water contg. kitchen garbage. This mixture is transferred in the fluid state and dehydrated and residue on dehydation is solubilized and subjected to methane fermentation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention collects domestic waste and domestic wastewater discharged from each household quickly and easily, recovers effective resources from them, and at the same time, prevents the environmental pollution. And a method for treating wastewater.

[0002]

2. Description of the Related Art In recent years, due to abundant consumption materials, changes in packaging materials, and an increase in domestic wastewater due to population concentration in cities,
The amount of waste and wastewater in cities tends to increase rapidly, and the fact is that each local government is having a hard time dealing with such waste.

That is, as the main wastes of municipal wastes, there are glass containers, so-called non-burnable refuses such as metals, paper wastes, kitchen wastes, etc., but only a small portion of the glass containers, metals and waste papers in them. Most of the waste is incinerated or is used for landfill just after being collected and reused, but with the shortage of incineration facilities and landfill, the collection capacity is approaching the limit, causing a major social problem. Is becoming.

On the other hand, the amount of domestic wastewater from kitchens, baths, laundry, toilets, etc. is gradually increasing as the living standard of each person rises, and the shortage of water resources in the future cannot be avoided.

[0005]

In view of such circumstances, the present invention provides a means to replace the conventional collection of urban waste by land transportation, and collects the accumulated waste and waste water. The purpose was to recover effective resources from the plant and reduce the amount of waste for incineration and landfill disposal.

[0006]

[Means for Solving the Problems] As a result of various studies on comprehensive treatment of municipal waste and wastewater, the present inventors found that
As a collecting means, instead of the conventional transportation by a garbage truck, if the waste and waste water are mixed and a fluid transfer system is adopted, the problem of collection can be solved, and the mixture can be solubilized to remove organic matter. Based on this finding, we found that if a high-concentration solution is used and this is methane-fermented, methane can be efficiently produced, effective resources can be recovered, and the amount of incineration and landfill can be significantly reduced. The present invention has been completed.

That is, according to the present invention, (a) a step of separating and removing incombustible solid matter from solid waste, (b) a step of crushing the obtained combustible solid matter, and (c) a crushed matter A step of mixing with domestic wastewater containing food waste, (d) a step of transporting and accumulating this mixture by fluid, (e) a step of dehydrating the accumulated mixture, (f) a step of solubilizing the dehydrated residue, The present invention provides a method for treating waste and wastewater, which comprises (g) methane fermentation of a solubilized product, (h) recovery of methane from a methane fermentation product, and (ii) separation of water from residual liquid. Is.

The present invention will now be described in more detail with reference to the accompanying drawings. FIG. 1 is a process diagram of the method of the present invention, in which solid waste in municipal waste is first separated into a non-combustible solid material and a combustible solid material, and only the combustible solid material is crushed. (B), where it is crushed to a size that does not hinder fluid transport.

Next, this crushed material is mixed with domestic wastewater containing food waste in the mixing step (c) to form a suspension-like mixture, and then the fluid transfer step (d) using a fluid transfer pipe, for example, a sewer pipe is performed. It is accumulated in a predetermined place, for example, a water collection tank. Prior to being mixed with domestic wastewater, the above kitchen waste can also be ground to facilitate subsequent processing.

The mixture of the crushed combustible solid material, the food waste and the domestic waste water thus accumulated is then subjected to a dehydration treatment (e). This dehydration is performed by filtration using a filter cloth or centrifugation. This treatment removes more than 95% of the water in the waste.

In this way, the residue after dehydration is then subjected to a solubilization treatment (f). This solubilization method includes a biological solubilization method performed by using a microorganism and a chemical solubilization method performed by pressurizing and heating in the presence of a catalyst, but only the former may be used. You may use both together. Prior to solubilization, if necessary, solid matter that is difficult to solubilize, such as plastics, can be separated and removed by filtration or sedimentation. In this case, in the crushing step (b), it is advantageous to adjust the particle size of the plastics to be larger than the particle size of other solids, and to separate the plastics with different sieves in this step.

This solubilized product is sent to the methane fermentation treatment step (g), where organic substances are decomposed by the action of methane-fermenting bacteria to generate methane. Until now, a method of methane fermentation of this has been proposed as one of the effective uses of domestic wastewater, but the optimum organic matter concentration of methane fermentation is 50.
Since the organic matter concentration in ordinary domestic wastewater is remarkably low at about 200 ppm as compared with 00 ppm or more, it could hardly be used for the purpose of obtaining methane. On the other hand, in the present invention, since garbage and combustible solid matter are solubilized and dissolved in the domestic wastewater and the concentration of organic matter is increased, efficient methane fermentation is performed.

The methane gas produced in the above-mentioned methane fermentation step is recovered (h) by an appropriate means, purified if necessary, and then used for fuel or other purposes. Also,
The residual liquid after recovering methane is sent to a water separation step (ri), and after water is separated, the rest is subjected to a waste treatment. The separated water is sent to the regeneration step together with the water obtained in the dehydration step (e), if necessary, to be regenerated and reused.
FIG. 2 is an explanatory view showing an example of an apparatus for separating incombustible solids such as glass and metals from solid wastes and crushing combustible solids. The magnetic sorter 1 removes the metals contained therein, and then the baffle 2
After the glass container is removed by the action of 1, the glass container is sent to the crushing device 3. The crushing device is composed of a rotating drum 4 and cutters 5 and 6, and the combustible solid matter B contacts the cutters 5 and 6 by the rotation of the drum 4, where the combustible solid matter B has a size that does not hinder the fluid transfer, usually 1. It is crushed to about 10 mm and discharged from the outlet 7.

FIG. 3 is a path diagram showing an example of the fluid conveying process of the present invention, in which the combustible solid material crushed by the crushing device 3 enters the mixing tank 10 through the pipe line 8, where After being mixed with domestic drainage such as selective drainage, kitchen drainage, and toilet drainage sent through the pipe line 9, it is accumulated in the centralized tank 12 by the fluid transfer pipe 11. In addition, 13 is a vacuum pump for exhausting.

FIG. 4 is an explanatory view showing an example of a reaction apparatus for carrying out the chemical solubilization step, in which domestic wastewater and combustible solids introduced into the auxiliary chamber 15 through the introduction port 14 of the reaction apparatus. The mixture with the substance is mixed with the oxidizing gas from the introduction pipe 16 if necessary, and then sent to the reaction chamber 18 and discharged from the discharge port 20 through the catalyst layer 19. During this time, the poorly soluble organic matter in the mixture is decomposed into soluble organic matter and becomes in a dissolved state. At this time, in order to accelerate the reaction, it is possible to heat from the outside or pressurize by the pressurizer 17 if necessary. By this chemical solubilization treatment, cellulose and synthetic resin in the mixture are decomposed into monosaccharides and carboxylic acids, nitrogen compounds are decomposed into nitrogen gas through ammonia and sulfur compounds are decomposed into sulfates through sulfides.

FIG. 5 is an explanatory view showing an example of an apparatus for carrying out the biological solubilization process. A mixture of domestic wastewater and combustible solids is fed into the reactor 21 through the inlet 22. The solid organic matter C present therein is converted into the soluble organic matter D by the action of the solubilizing bacterium E here. At this time, the mixture in the mixture is the temperature control means 23 and the pH control means 2
The optimum temperature and the optimum pH are maintained by means of No. 4 and, if necessary, agitated by an agitator 25. The liquid component of the solubilized product is discharged from the discharge port 26 through the filter tube.
By this biological solubilization treatment, the polysaccharides in the mixture are decomposed into monosaccharides, proteins into amino acids, and neutral fats into higher fatty acids.

FIG. 6 is an explanatory view showing an example of an apparatus used in the methane fermentation process of the present invention, in which the solubilized liquid is introduced into the methane fermentation tank 27 through the inlet 28, where methane is added. It is mixed with fermenting bacteria and subjected to methane fermentation.
The methane fermentation broth is optimally controlled by the pH adjusting means 29, the temperature adjusting means 30, and the nutrient source adjusting means 31, and is stirred by a stirring machine 32 as necessary so that the reaction is carried out uniformly. The methane gas generated by the reaction is taken out through the exhaust port 32, and the reaction liquid is continuously taken out through the separation membrane 34. Reference numeral 35 is a baffle plate for smooth circulation of the liquid.
In this methane fermentation process, monosaccharides and amino acids in the solubilized liquid are decomposed into methane through butyric acid and propionic acid, and higher fatty acids are converted into methane by lowering.

The methane thus obtained can be used as an industrial raw material after being produced if necessary,
Further, it can be used as a fuel gas as it is or mixed with other combustible gas.

On the other hand, water can be regenerated from the solution extracted from the methane fermentation tank through the separation membrane, for example, by using a permeable membrane.

[0020]

According to the present invention, CO _{2 is} environmentally friendly.
Gas, NO _x gas, SO _x gas generation is suppressed, the effect of reducing the amount of sludge and incineration ash generated is obtained, and by transporting fluid, there is no waste left on the road, and it is possible to reduce the number of transportation trucks. There are advantages.

Further, it has a great effect on the recovery of effective resources in terms of the generation of methane gas and the regeneration of water, and is also significant in terms of maintaining a clean environment by disposing of garbage when it is generated.

[0022]

EXAMPLES Next, the present invention will be described in more detail by way of examples. Example Solid waste containing paper, plastic, metal, glass 9
From 00 grams, non-combustible solid metal, glass 8
0 gram is manually removed and crushed with a roll crusher to a particle size of about 3-6 mm. This is kitchen 37
Mix 0 gram with a disposer to a particle size of 3 mm or less, and use 237 liters of waste water such as toilet, bath, laundry, etc., and collect it about 100 meters away through a normal polyvinyl chloride sewer pipe. Transfer the fluid to the tank. At this time, no troubles due to the mixing of the solid matter were recognized.

Next, the solid and liquid mixture collected in the collecting tank is filtered through a nylon filter cloth to dehydrate it to a water content of about 2 to 3% by weight. Next, this filtration residue is treated under the presence of an alkali catalyst at 70 atm and 25
After decomposing at 0 ° C. to solubilize plastics, the plastics are further introduced into a microbial decomposition tank to solubilize solids.

When the solubilized solid matter was sent to a methane fermentation tank and treated there for 5 hours, about 180 g of methane gas and about 119 g of carbon dioxide were obtained. Further, water is recovered from the fermentation residue through a separation membrane and mixed with water dehydrated in the filtration step,
When it was supplied to a water treatment reactor and treated, about 60 liters of reclaimed water was obtained. The fermentation residue after dehydration was about 185 grams, which was about 1/7 of the initial solid waste amount.

[Brief description of drawings]

FIG. 1 is a process drawing of the method of the present invention.

FIG. 2 is an explanatory view of a combustible solid material crushing device used in the present invention.

FIG. 3 is a path diagram of a fluid transfer process of the present invention.

FIG. 4 is an explanatory diagram of a reaction apparatus for carrying out the chemical solubilization step of the present invention.

FIG. 5 is an explanatory view of an apparatus for carrying out the biological solubilization step of the present invention.

FIG. 6 is an explanatory diagram of a methane fermentation apparatus used in the present invention.

[Explanation of symbols]

 3 Crushing device 4 Rotating drum 5, 6 Cutter 10 Mixing tank 11 Fluid transfer pipe 18 Reaction chamber 19 Catalyst layer 21 Reactor 27 Methane fermentation tank

Claims (1)

[Claims] 1. A process of (a) separating and removing incombustible solids from solid waste, (b) a process of crushing the obtained combustible solids, and (c) a process of crushing the crushed products including garbage. A step of mixing with domestic wastewater, (d) a step of fluid-transporting and accumulating this mixture, (e) a step of dehydrating the accumulated mixture,
(F) a step of solubilizing the dehydrated residue, (g) a step of subjecting the solubilized material to methane fermentation, (h) a step of recovering methane from the methane fermentation product, and (ri) separating water from the residual liquid A method of treating waste and wastewater, which comprises steps.