JPH11267700A - Electrically sterilizing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the capacity of human waste treatment and to reduce cost by sterilizing highly concentrated sludge flocculated to form floc by applying low voltage DC current to human waste septic tank sludge and simultaneously forming and recovering. SOLUTION: A small-sized lightweight human waste sludge concentrating device 11 is provided in a line for pulling out excess sludge. A titanium electrode as an anode and a stainless electrode as a cathode are provided in the human waste sludge concentrating device 11 and week DC current is applied between the electrodes. The human waste sludge is agglomerated to cause flocculation action by applying current to break the negatively charged hydration of the human waste sludge. A turbidity component is removed by the bond by van der Waals force with the flocculation action. The sludge has about pH 6.5-7 and then, the ζ-potential of the turbidity particle is neutralized to lower the turbidity and to increase a supernatant to be highly concentrated. The recovered sludge is easily reutilized because the sterilization effect occurs at the same time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a method for concentrating and sterilizing sludge from human waste septic tanks and a method for killing and sterilizing viruses and general bacteria in effluent water, fresh water and seawater by low voltage and direct current.

2. Description of the Related Art Excessive sludge removal in a human waste septic tank has conventionally required periodic collection, disposal and operation, but costs have been incurred. Economic difficulties, etc.,
At present, no other method has been found. The same applies to viruses and general bacteria in effluent water, fresh water, and seawater. They rely on chlorine disinfection, but the use of chlorine tends to be reduced as much as possible, but there is no other method.

[0003] The present invention is more cost-effective than the present state, although the improvement of the removal of excess sludge is an urgent issue in relation to the treatment capacity of a sewage treatment plant, The task was to reduce the review of the entire facility, such as space, and to operate it with existing facilities. The effluent is chlorine-sterilized, but has significant effects on rivers and marine life. On the other hand, due to the emergence of new species such as pests, viruses, and general bacteria in fresh water, the terminal fresh water has no killing effect even if chlorine is injected without any countermeasures as seen in the O157 disturbance. The same applies to seawater, and it is an object of the present invention to provide a technical method for preventing native fish and shellfish from being completely annihilated by a virus or the like attached to a fish or shellfish imported from a foreign country.

[Means for Solving the Problems] In order to achieve the above object, the human waste sludge concentrating apparatus according to the first aspect of the present invention is small, lightweight, easy to install, and safe. Are used as an anode and a cathode, and when a direct current is applied, the hydration of the negative charge of the excreta sludge is broken to cause agglomeration and agglomeration action. The coupling by Juan Thea Varska made it possible to remove the turbidity components. Since the sludge has a pH of about 6, 5 to 7, the data potential of the turbidity particles is neutralized and the turbidity is reduced.
It was increased to 70%, enabling high concentration. At the same time, the sterilization effect was generated, and the reuse of the recovered sludge was facilitated.
The apparatus for sterilizing discharged water, freshwater and seawater viruses, general bacteria, and the like according to claim 2 is small, lightweight, easy to install, and safe, and discharges water by applying a direct current to a titanium electrode or a stainless steel electrode as an anode and a cathode. It is possible to sterilize within a very short time within a range that does not generate chlorine in fresh water and seawater.

[Operation] The night soil sludge concentrating apparatus according to the first aspect of the present invention has the following operation. Titanium electrode,
By applying a weak DC current to the stainless steel electrode, the electric action made it possible to generate non-polluting, highly concentrated, urine sludge and simultaneous sterilization without elution of chemical substances. The present invention breaks down the hydration of sludge's negative charge and, at the same time, reduces the turbidity due to the binding effect by Juan der Varska due to the coagulation effect of agglomeration, increasing the supernatant water to 60-70% and increasing the high concentration. It has become possible. Addition of the stirring action resulted in further accelerated settling. It does not require any diluting water, and has the advantage of improving the capacity of existing human urine facilities. Night soil pH is 6,5
Approximately 7 so that the coagulation effect is the best and the addition of aluminum, alum and irons is not mainly required, and no heating equipment is required. The cost is reduced, the cost is reduced, and the sludge removal cost is reduced. . About 10 to prevent electrode contamination
The polarity is switched every minute, and the electrode is always cleaned.

The electric sterilizer for discharged water, fresh water and seawater according to claim 2 of the present invention has the following operation. The effluent has a great effect on rivers and marine organisms such as fish and shellfish, and the sewage treatment plant is trying to limit chlorine injection as much as possible and not kill them. However, Escherichia coli can be killed only by chlorine injection, and the bactericidal effect of the present invention is expected. In fresh water, chlorine sterilization method is adopted. However, if the generation of harmful substances such as trihalomethane and the amount of chlorine injected are small, there is often no sterilization effect at the end of the long distance water supply pipe, and the survival of O157 etc. has a bad effect on the human body. Have given. For this reason, the adverse effect of increasing the chlorine injection amount has occurred, and it is currently difficult to deal with the problem from a safety point of view. In the case of ultraviolet sterilization, the cost is longer than the life of the lamp, and the effect is not perfect. For this reason, as a result of applying a direct current while alternately switching the polarity of the titanium electrode and the stainless steel electrode at the end of use of the effluent water and fresh water of the present invention, viruses and general bacteria are killed without using any auxiliary agents such as chemicals and salt. Became possible. Similarly, in seawater, when a direct current in a range where no chlorine was generated by electrolysis was applied, an electron transfer reaction between the cell and the electrode occurred, and the cell was sterilized at the positive electrode. For this reason, it is attracting attention as a method for killing new viruses and general bacteria harmful to marine organisms such as virus damage to clams, pearl oysters, oysters, and the like.

An embodiment of the present invention will be described below in detail with reference to the drawings. A first embodiment will be described with reference to FIG. This example shows a standard process of the activated sludge process. Human waste 1 is collected in the adjusting tank 2, and after homogenization, pH adjustment,
Then, the air 4 for aeration and aeration is injected into the reactor, and the activated sludge is oxidatively decomposed into organic substances by a fixed residence time. The activated sludge is mixed with human waste and enters the sedimentation tank 5, where it is retained for 2 to 3 hours to separate the activated sludge from the supernatant and settle naturally. The supernatant of the precipitation tank 5 is discharged as discharge water 6. The settled sludge is collected in the lower center of the sedimentation tank 5, and is returned to the hot air tank 3 and is circulated and used as return sludge 7 by the return sludge pump 8. The amount corresponding to the sludge multiplication amount in the steam tank 3 is withdrawn as excess sludge 9, dried, incinerated, and landfilled. The chlorinator 10 sterilizes the effluent 6. Activated sludge forms flocs in a group of microorganisms, so that organic matter is adsorbed and the microorganisms (bacteria, mold,
Algae) oxidize and decompose into carbon dioxide and water with the energy required for their own reproduction. If the balance between the adsorption and the oxidation is lost, clear effluent is not obtained and the water becomes turbid. Floc is physically adsorbed on the outer periphery of activated sludge and is 0, 7 to 1 ×
It is negatively charged at about 1.5 microns. When a direct current is applied to this, agglomeration may occur. The surplus sludge generation amount is conventionally
0 per 1 k9 of treated BOD (biochemical oxygen demand)
3-0, 4 kg, but 0, 2
It decreased by about 60% to less than kg. As a result of saving 60% of the conventional cost, the processing load has a margin of 60% in terms of capacity, resulting in a sense of security in the maintenance and management of the facility. . The polarity was switched for 10 minutes as a variable type.

Next, a second embodiment will be described with reference to FIG. In this embodiment, an electric sterilizer for discharged water, fresh water and seawater is shown. The raw water 1 pressurized by the pump enters the center of the container 2 and passes through a titanium wire mesh or a stainless steel wire mesh constituting the anode 3 on the inner periphery. While the spacing piece 4 passes through the outer periphery of the cathode 5 composed of a titanium wire mesh or a stainless wire mesh, the treated water 7 containing viruses and general bacteria 7 has an effect of killing. In this case, the weak current is applied at normal temperature and normal pressure, and there is no change in PH or the like. The titanium electrode can be used semi-permanently by processing such as platinum plating and palladium oxide coating, and the polarity switching device 8 automatically switches and uses the anode and the cathode approximately every 10 minutes.

The night soil sludge concentrator according to the above embodiment has the following effects. (1) Escherichia coli count 2, surplus sludge of 600 / ml as anode,
The residence time of 60 minutes in the vessel in which a cathode respective electrode area 1 m ² electrode distance 2 mm, supernatant water is increased to 60% to 70%. When this was further stirred, the supernatant water became 60 to 70% even when the residence time was 40 minutes. Agitation produced a coagulation promoting effect. The sterilization rate is 800 ml /
When water was supplied by a pump for 100 minutes, 100% sterilization became possible. In this case, the electrodes were sandwiched by insulating nets of the gap pieces so that the anode and the cathode did not come into contact with each other, and were formed into net-like electrodes so that excess sludge could easily pass through. The applied voltage was 3 V, 250 mA.

Next, the electric sterilizer according to the above embodiment has the following effects. (1) The number of Escherichia coli at 2,500 cells / ml in the discharge water was passed at 800 ml / min by the present invention without chlorine sterilization, and the number of viable bacteria was reduced to zero by applying a DC voltage of 3 V and 500 mA. (2) 500 bacteria / ml of general bacteria in fresh water were brought to a state of zero chlorine, and then water was passed at 800 ml / min.
The number of viable bacteria was reduced to zero by V500 mA. (3) To use general bacteria and viruses in seawater as clam shellfish sterilized seawater, 3 liters of seawater container at 1.5v5mA
As a result of immersion for 15 seconds, the number of viable bacteria was zero.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the present invention includes a specific method of the present invention and a specific design change of members and equipment used in the method. For example, it is possible to arbitrarily set the diameter of the titanium electrode, the method of insertion, the amount of insertion, the surface treatment, the voltage between the electrodes, the current, the time for polarity conversion, and the like. Further, the materials of the anode and the cathode are arbitrary, and materials used in a range in which generation of chlorine does not occur can be added, and the configuration of the electrode as a rod is included.

[Effect of the Invention] In the night soil sludge concentrating apparatus according to the first aspect of the present invention, since the above-mentioned method is employed, if excess sludge is conventionally extracted at a sewage treatment plant and incinerated as industrial waste, it causes global warming and landfill. As a result, soil contamination and the like due to wastewater occurred, and a drying process was required for use as compost for agriculture, and it could not be reused. In addition, in modern times when the sewerage system has been promoted, there is no countermeasure even if research is conducted day and night to prevent the chemical damage caused by chlorine. The reduction of excess pollution is directly linked to the reduction of trucks, traffic volume and exhaust gas pollution, reducing running costs,
With the aeration tank and sedimentation tank remaining as they are, the effect of reducing the burden of economic public works expenses, which can sufficiently cope with the increase in load associated with sewerage development, will be returned to the interests of Japan itself, and expectations are extremely high. large. This is a method for utilizing the negative charge of an organism as a natural potential, which is extremely low in terms of electric power, which also causes pH fluctuation and temperature change, and has no adverse effect on other places other than the application of the present invention. There is no relief. In addition to energy and cost savings, titanium can be used for a long period of time and can be recovered, making it possible to reuse the recovered titanium. Such economic effects are also very large.

In the method for sterilizing discharged water, fresh water, and seawater according to the second aspect of the present invention, since the above method is employed, it is very easy to increase the size of the present invention, and large-scale treatment is possible. As a result of being applied to discharge water, freshwater, and seawater, it has become possible to prevent any adverse effects on the environment in the water field.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an apparatus relating to the method according to claim 1;

FIG. 2 is an explanatory view showing an apparatus relating to a method according to claim 2;

[Explanation of symbols]

 1, human waste Fig. 12, adjustment tank 3, aeration tank 4, air 5, sedimentation tank 6, effluent 7, return sludge 8, return sludge pump 9, excess sludge 10, chlorinator 11, sewage sludge concentrator

[Explanation of symbols]

 1, raw water Fig.2 2, container 3, anode 4, gap piece 5, cathode 6, treated water 7, virus, general bacteria 8, polarity switching device

Claims (2)

[Claims] 1. A human waste sludge concentrator characterized by a method of sterilizing a high-concentration sludge formed by coagulation and floc formation of a night soil sludge by a low voltage and a direct current and simultaneously producing and collecting the sludge. 2. An electric sterilizer for discharged water, fresh water, and seawater, which is characterized by killing and sterilizing viruses and general bacteria in the discharged water, fresh water, and seawater with a low voltage and a direct current.