JPH0336600B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides industrial wastewater discharged from various factories;
Excess sludge inevitably generated by various biological oxidation devices that purify miscellaneous sewage such as kitchen sewage, human waste sewage, bath sewage, laundry sewage, etc. from hotels, inns, restaurants, etc. is treated with biological reduction without separate collection and disposal. The present invention relates to a method for treating surplus sludge that is completely digested, and an apparatus therefor.

(Prior art) Conventionally, as a method for treating surplus sludge that naturally accumulates at the bottom of each treatment device during the purification treatment of miscellaneous sewage as described above, the surplus sludge is collected using a vacuum, etc., and then dehydrated and dried. and incinerate it, or
Anaerobic digestion, which aims to effectively utilize the sludge by dewatering it and then landfilling it, dumping it in the ocean, dewatering it and composting it, or reducing the amount of excess sludge, has a simple structure of the treatment facility and is relatively easy to operate. Therefore, it has been used for a long time as a sludge treatment process in sewage treatment, but the treatment takes six to eight months, and it is not actually used effectively in terms of capacity and area. .

(Problems to be Solved by the Invention) However, in these methods of treating surplus sludge, after dehydrating the sludge with a water content of 98% using a dehydrator, incineration treatment requires combustion costs and facilities to burn it. Construction costs, transportation costs and vast landfill sites for landfill treatment, transportation costs and ocean pollution problems for ocean dumping, and increased use of chemical fertilizers for composting Nowadays, however, the utility value of composted sludge is decreasing, and while all of these treatment methods require enormous costs and a great deal of effort, they also have various problems.

In addition, sludge treatment using the anaerobic sludge digestion method, which has been used for a long time, has a slow biological reaction temperature, so the scale of the treatment facility must be enlarged, which increases construction costs. It generates a large amount of bad odor, and the daily management of the treatment facility is extremely important, requiring a considerable amount of time and effort.Furthermore, the desorbed liquid after treatment has a high concentration of organic matter; This method has problems such as requiring secondary treatment of the liquid, and an efficient method for treating excess sludge is desired.

(Means for Solving the Problems) The present invention was created in view of the current situation, and it is possible to eliminate surplus sludge that is inevitably generated from various purification treatment facilities without requiring huge construction costs and daily management. The system was designed to efficiently decompose and digest excess sludge without requiring any effort. Excess sludge is accumulated in a sludge digestion reaction tank with a fixed capacity, and an anaerobic system is installed in a large number of porous bodies arranged at the bottom of the tank. Lower microorganisms such as anaerobic bacteria are maintained and cultured, and emulsifying surfactants extracted from plants and steroid-based or tolterpene-based saponins are mixed in the middle of the tank. This method uses bacteria to efficiently digest sludge in a short period of time to perform anaerobic digestion.

(Function) Due to the structure of the present invention, anaerobic treatment is generally avoided because it is accompanied by a bad odor and has a slow digestion rate. By adding saponin and emulsifying surfactant to the middle of the tank while maintaining and culturing , soil bacteria, and other lower microorganisms, the synergistic effect of this is to energize anaerobic microorganisms and increase their activity. As the cycles of the acidic and alkaline fermentation periods become faster, the amount of methane gas generated per unit time increases by 25 to 35%, and hydrogen sulfide, mercaptan, indole, etc., which are often generated during the acidic decline period, are the causes of bad odors. This system efficiently performs anaerobic digestion while suppressing the generation of gases, decomposes and digests excess sludge, and turns it into clear water.

(Embodiment) To explain one embodiment of the present invention, there is a surplus sludge introduction pipe 2 that introduces surplus sludge into a sludge digestion reaction tank 1 with a fixed capacity according to the amount of treatment, and a supernatant water after decomposition and digestion that is introduced into the tank. A supernatant water outlet pipe 4 with a pump 3 attached to the lower end for discharging to the outside is installed, and a bacteria input pipe 5 for introducing soil bacteria, other lower microorganisms, etc. from the top of the tank to the bottom of the tank is also installed. A chemical input pipe 6 and a heat source zone 7 are installed on the inner side of the tank, respectively, for mixing steroid-based or tolterpene-based saponins and emulsifying surfactants extracted from plants from the upper part of the tank to the middle part of the tank, and then A low-speed stirrer 9 with an appropriate number of stirring blades 8, 8' mounted on the shaft is installed in the center of the tank,
Also, at the inner bottom of the tank, there are mesh plates or lattice plates 10, 1 made of highly corrosion resistant material such as stainless steel.
Porous bodies 13, 1 formed by compressing a spongy body 12 such as fibrous resin between 0' and frame plates 11, 11'.
A bacteria holding plate 15 formed by connecting a large number of 3'... with connecting rods 14, 14' is fixed upright for a long time in an oblique or vertical manner, and this porous body 13, 13'... It is designed to maintain and cultivate soil bacteria and other lower microorganisms introduced through the input pipe 5, and 16 in the figure is an insoluble inorganic substance discharge pipe.

The present invention has the configuration as described above, and includes a large number of porous gas bodies 13, 13', which are installed upright at the bottom of the sludge digestion reaction tank 1 that accumulates a certain amount of sludge.
Due to the synergistic effect of soil bacteria and other lower microorganisms maintained and cultivated in the tank, steroid-based or tolterpene-based saponin and emulsifying surfactant mixed into the middle of the tank from the chemical introduction pipe 6, acidity is generated during decomposition and digestion of sludge. The cycles of the fermentation period and alkaline fermentation period are accelerated, and the amount of methane gas generated per unit time is 25 to 25%.
This method efficiently performs anaerobic digestion while suppressing the generation of odor-causing gases such as hydrogen sulfide, mercaptan, and indole, which are often generated during the period of acidity decline. At this time, the low-speed stirrer 9 is automatically activated two or three times a day by a timer to appropriately stir the surplus sludge with the stirring blades 8 and 8', and depending on the season, the heat source 7 is used to heat the sludge to 30°C.
If heated to 39°C, the synergistic effect between the lower microorganisms, saponin, and emulsifying surfactant will be further promoted, and the decomposition and digestion of sludge will progress, resulting in sludge being raised in a relatively short period of time. It is anaerobically digested into clear water.

(Effects of the Invention) After surplus sludge is introduced into the sludge digestion reaction tank 1 according to the present invention through the surplus sludge introduction pipe 2 within a certain volume according to the amount of treatment, the porous bodies 13, 13' at the bottom of the tank...
Lower microorganisms are introduced into the tank through the bacteria input tube 5, planted, maintained and cultured, and then saponin and emulsifying surfactant are mixed into the middle of the tank through the chemical input tube 6. The fermentation cycle is accelerated, and anaerobic digestion is performed while generating odorless gas even during the acidity decline period.As shown in Figures 6 and 7, the sludge digestion reaction tank 1 is divided into three tanks. The continuous one can be selected and used as appropriate depending on the processing capacity of the biological reduction treatment equipment. Further, the supernatant water after the sludge decomposition treatment is discharged from the supernatant water outlet pipe 4 by the operation of the pump 3, and then a fixed amount of surplus sludge is introduced into the sludge digestion reaction tank 1 from the surplus sludge introduction pipe 2 again. The same decomposition treatment as before is carried out, except that the porous body 13,
Since the lower microorganisms etc. maintained and cultured in 13' are alive, there is no need to reintroduce them. On the other hand, the supernatant water discharged from the supernatant water outlet pipe 4 is returned to the biological oxidation treatment tank in the biological oxidation treatment equipment, so that the saponin and emulsifying surfactant are absorbed by the aerobic bacteria in the biological oxidation treatment tank. It also has the secondary effect of giving vitality to the body and improving the biological oxidation treatment capacity by 20 to 30%.

The present invention does not require collection by vacuum, etc. as in the past.
Excess sludge is efficiently digested without incurring dehydration, combustion, transportation, and landfill costs, and without destroying the natural ecological cycle, making it an extremely effective method that eliminates the need to worry about environmental pollution. It is useful.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is a front view of a porous gas body.
Fig. 4 is a partially cutaway enlarged view of the porous gaseous body, Fig. 5 is a perspective view showing the continuous state of the porous gaseous body, and Figs. 6 and 7 show the continuous sludge reaction tank (3 tanks) of the present invention. FIG. 2 is a longitudinal sectional view and a plan view thereof. In the figure, 1... sludge reaction tank, 2... sludge introduction pipe,
3... Pump, 4... Supernatant water outlet pipe, 5... Bacterial introduction pipe, 6... Chemical introduction pipe, 7... Heat source zone, 8,
8'... Stirring blade, 9... Low speed stirrer, 13,1
3'...Porous body.

Claims (1)

[Claims] 1 An excess sludge introduction pipe that introduces excess sludge into a sludge digestion reaction tank with a fixed capacity depending on the amount of sludge to be treated, and a supernatant water tank with a pump attached to the lower end to discharge the supernatant water after decomposition and digestion to the outside of the tank. In addition to installing a discharge pipe, there is also a bacteria input pipe for introducing soil bacteria, other lower microorganisms, etc. from the top of the tank to the bottom of the tank, and in the same way, steroids or tolterpene extracted from plants from the top of the tank to the middle of the tank. A low-speed stirrer with a chemical input pipe for mixing saponin and emulsifying surfactant, and a heat source zone on the inner side of the tank, and an appropriate number of stirring blades attached to the center of the tank. In addition, the inner bottom of the tank contains a large number of porous materials formed by compressing spongy bodies such as fibrous resin between corrosion-resistant mesh or lattice plates such as stainless steel and frame plates. Bacteria holding plates connected by connecting rods are erected and fixed in an oblique or vertical manner for a long period of time, and this porous body is used to store soil bacteria and other lower microorganisms that are introduced from the above-mentioned bacteria input pipe. Excess sludge processing equipment that maintains and cultivates sludge.