JPS6345878B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method and apparatus for treating human or other animal excrement, and is suitable for quickly, highly efficiently, and pollution-free treating excreta suitable for ships, trains, aircraft, remote islands, coastal areas, etc. The present invention provides a compact and simple automatic chemical treatment method and device for excrement. The excrement referred to in the present invention refers to so-called excrement and urine. This includes water-soluble nitrogen compounds such as ammonia and urea, free fatty acids, and water-soluble proteins.
BOD, COD substances, suspended solids, solids such as cellulose, E. coli, pigments such as bile pigments, skatole,
Contains odorous substances such as mercaptans. Conventionally, biological treatment methods that mainly use activated sludge have been used to treat excrement on land. This is a method based on the so-called biochemical action in which aquatic microorganisms that grow in the sludge bed metabolize and decompose excreta in an aerobic or anaerobic manner. Therefore, this method focuses exclusively on making the microorganisms function efficiently. Efforts are being made to improve. However, this method
It has the following well-known drawbacks: In other words, the decomposition rate of microorganisms is slow, resulting in a large sludge floor area, and the types of microorganisms and their propagation are highly dependent on subtle changes in water quality, making it difficult to automate water quality management. These drawbacks are still unresolved, and for example, excrement
It requires an installation volume of approximately 50m ³ and a processing time of 1 day to process 100 ml of water, so it can be used only in cases where long-term processing is permitted. Therefore, in ships, trains, aircraft, etc., untreated excrement is currently collected and transported to treatment facilities on land or dumped at sea.
In this industry, there is a strong desire to establish a pollution-free treatment method for excrement that can be carried out on-site at any time using sanitary and compact treatment equipment. In view of the above-mentioned current situation, the inventors of the present invention have conducted intensive research on methods and devices for treating excrement, and have discovered that oxidation treatment of excrement while circulating it with sodium hypochlorite can decompose it surprisingly quickly. By combining a compact oxidation treatment method for discovering and oxidizing treatment and a means for detoxifying the oxidizing agent remaining in the oxidation treatment solution using a reducing agent, we have developed a method that can perform pollution-free treatment using compact equipment. This finding led to the present invention. That is, in the present invention, sodium chloride is added to excrement, a circulation path is formed for the added liquid, and an electrolysis section is provided in the circulation path to generate sodium hypochlorite and oxidize the excrement. The present invention relates to a method for treating excrement, which is characterized in that the sodium hypochlorite remaining in the oxidized liquid is then rendered harmless with a reducing agent and then drained. The present invention also provides an excrement oxidation tank having an excrement introduction part and a treatment liquid discharge part, a circulation path including the oxidation tank,
A means for introducing salt into the circulation system, a means for electrolyzing the salt, and a means for detoxifying sodium hypochlorite remaining in the oxidizing tank by reducing it. It relates to a processing device. In a preferred embodiment of the present invention, an oxidation treatment means is provided in an excrement storage tank (excrement tank) provided on a ship, etc., and a detoxification treatment means is connected to the oxidation treatment means.
This makes it possible to speed up, make compact, pollution-free, and automate the disposal of excrement. In addition, the excreta is treated with suspended solids,
It is desirable to remove solids. Removal is usually
This is done using a filter, and the excess liquid is sent to the excrement inlet of the excrement tank using a pump, etc. It may be circulated between the excrement tank and the waste container. The excrement is then oxidized with sodium hypochlorite. Sodium hypochlorite is the most preferred among oxidizing agents in terms of oxidizing power, cost, and practicality. In the present invention, the important points are that sodium chloride is added to the excrement, and the sodium chloride-containing liquid is self-supplied by electrolysis, and that the excrement is circulated together with the oxidizing agent for oxidation treatment. The sodium chloride component is supplied by supplying solid sodium chloride as it is or by supplying seawater. There is a method of using sodium hypochlorite stored in a tank, but the method of self-supplying by electrolytic means consists of a small electrolytic tank and a DC current supply device, which requires less installation volume and equipment weight, and is easy to handle. is easy and safe. Treatment by electrolytic means involves adding pumped seawater to an excrement tank (hereinafter this excrement tank will be referred to as an oxidation tank). There is a method in which an oxidation tank and an electrolytic tank are connected in a cyclical oxidation process, and a method in which the two are connected in a straight line. Cyclic oxidation treatment is advantageous because less sodium chloride or seawater is used. Circulating oxidation treatment using seawater electrolysis is particularly preferable for ships with long voyages. Below, we will mainly explain the seawater electrolysis method.
Regarding the method of supplying solid sodium chloride, the conditions may be similar to those for seawater electrolysis. Electrolysis can be carried out efficiently if seawater is supplied at least 1.4 times the amount of excrement. About 4 to 6 times is preferable. However, using a large amount is not preferable because it increases the size of the excrement tank. The oxidizing agent is
Water quality can be maintained within wastewater standards by supplying 0.8 to 1.5 times the oxidation equivalent of excrement. Preferably 1.0-1.2
Supply twice. Circulating oxidation treatment uses liquid circulation to
As the oxidant concentration increases and the liquid stirring effect increases,
This is preferable because the oxidation reaction proceeds sufficiently. The purpose can be sufficiently achieved if the total amount of liquid in the oxidation tank is circulated within the range of 0.5 to 50 times per hour.
It is preferable that the concentration of the oxidizing agent in the oxidizing tank is several tens to 10,000 ppm since high current efficiency can be obtained. The cyclic oxidation treatment usually takes several hours. Furthermore, since heat is generated during the reaction, cooling may be required if necessary. As the electrode plate of the electrolytic cell, it is preferable to use a material that does not dissolve during electrolysis. For example, the anode may be made of platinum, titanium with a platinum layer stacked on top, and the cathode may be made of titanium, stainless steel, iron, or the like. The seawater electrolyzer is
General commercially available products can be used, and there are no particular limitations as long as the gist of the present invention is achieved. Nitrogen gas and carbon dioxide gas are generated during the oxidation process, and hydrogen gas is generated in the electrolytic cell. It is preferable to exhaust these mixed gases by blowing air with a blower or the like, or by suctioning the gas. In addition, floc-forming metal ions such as Mg ²⁺ and Ca ²⁺ in seawater take in some water-soluble organic matter during electrolysis and precipitate as a precipitate called scale. Preferably, a removal means is provided in the circulating oxidation treatment line. The filter is usually made of non-woven fabric, net, etc. made from oxidation-resistant material.
If the reaction continues for a long time due to scale precipitation, dissolution of carbon dioxide gas generated in the oxidation reaction, generation of organic acids, etc., the pH of the processing solution may decrease and the oxidation reaction may be hindered. The oxidation tank is equipped with a means for supplying an alkaline substance to adjust the pH. As alkaline substances, sodium hydroxide, calcium hydroxide, etc. can be stored as an aqueous solution in a tank and supplied with a pump, or fed as a solid, or magnesia, magnesium hydroxide, etc. can be packed in a tower.
It is used by passing the processing liquid through it or by packing it into a mesh bag and placing it in an oxidation tank. The amount of alkaline material supplied can basically be made proportional to the alkali equivalents of dissolved carbon dioxide, organic acids, and scale, but it also depends on the amount of seawater, which is a kind of buffer material. According to experimental results, it is not necessary when there is a lot of seawater, but when it is small, it is possible to maintain the PH within a predetermined pH range by supplying 1.0 to 100 g of sodium hydroxide per hour per hour of excreted fluid. In addition, adjusting the liquid level in the oxidation tank involves controlling the ratio of excreta to seawater and automatically controlling the operating status of the pump and electrolyzer to ensure that reactions occur under favorable conditions.
This is desirable because it can prevent overflow of the oxidation treatment liquid and prevent dry operation of pumps and the like. The liquid level adjusting means includes, for example, a water level detector and a relay device, and a device that sends a signal to a pump and a solenoid valve is used, and a general commercial product can be used. Although 70 to 95% of the excrement has been treated in the oxidized liquid, a large amount of highly toxic oxidizing agent remains, so a harmless treatment is then performed. The harmless treatment is performed by reducing the remaining oxidizing agent with a reducing agent. Any reducing agent may be used as long as it is a substantially harmless substance, but
Preferably, the reducing agent is a water-soluble reducing agent that reacts quickly and quantitatively with the oxidizing agent within a room temperature range. A suitable example is thiosulfate, but hydrogen peroxide can also be used. The amount of reducing agent may be 1 to 3 times the equivalent of the oxidizing agent to be reduced, but addition of a large excess of reducing agent is wasteful and should be avoided. The rendered harmless liquid is then drained out of the system. Each of the above means is compactly assembled and automatically operated by a power panel switch. FIG. 1 shows the basic coupling arrangement of the invention. In FIG. 1A, a sodium chloride storage tank 5 is provided in the oxidation tank 1, and in FIG. 1B, seawater 5 is pumped up. The reducing agent 6 can be supplied in the middle of the pipe from the liquid discharge part of the oxidizing tank 1 as shown in FIG. 1A, or can be directly supplied to the oxidizing tank 1 as shown in FIG. 1B. 3 is an electrolytic cell, and 4 is a DC power source. FIG. 2 shows a specific example in which each means of the present invention is provided with ancillary devices. The excrement accumulated in the oxidation tank 1 is circulated through the filtration vessel 2 and the pump _P1 . A fixed amount of seawater is supplied to the oxidation tank by pump _P2 . The water level in the oxidation tank is measured by a detector 7,
It is controlled by sending a signal from relay 8 to each pump. Seawater 5 containing excrement from the oxidation tank is
It is sent to the electrolytic cell 3 through a filter 9 and a pump _P3 , and is electrolyzed with a direct current from a rectifier 4 to produce sodium hypochlorite, which is then supplied to the oxidation cell 1.
Then, in the circulation system created by the oxidation tank and the electrolytic tank,
The oxidizing agent is circulated, and the excreta is subjected to cyclic oxidation treatment for several hours. In order to adjust the pH of the oxidation reaction as necessary, an alkaline substance is stored in an alkaline substance storage tank 10.
to the oxidation tank by pump P ₅ . The generated gas is exhausted by a blower 11. The scale is removed by a filter 9. pump
A reducing agent is supplied from a reducing agent storage tank 6 to the oxidized liquid discharged through P ₄ by a pump P ₆ , and the liquid is detoxified and discharged. In the next example, the apparatus shown in FIG. 2 was used, and the water quality was analyzed by the following method.

[Table] The color and odor of the treated water was determined visually and olfactory, and toxicity was determined using a bioassay using sardines. Example 1 Excretion (ammonia 3000ppm, urea 2%,
COD 5000ppm, BOD 400ppm) was operated using the apparatus shown in Fig. 2 and was continuously treated for one month. In Example 1-(1), (2), (3), and (4), the amount of the oxidizing agent supplied was 0.7, 0.8, 1.0, and 1.5 times the oxidation equivalent of the excrement, respectively. The equipment includes oxidation tank 1 (volume ^1m3 ), strainer 2 (volume 50), electrolytic tank 3 (volume 100),
Rectifier 4, 200 mesh net filter 9
(volume 50), blower 11 (volume 50), float type switch 7, relay device 8, 40 wt% sodium hydroxide storage tank 10 (volume 100), 40 wt% sodium thiosulfate storage tank 6 (volume 500), each pump P ₁ ~
_P6 was used. The experimental conditions and results are shown in Table 1 below.

[Table] In addition, the wastewater after detoxification treatment in Examples 1-(2) to 1-(4) was colorless and odorless with zero Escherichia coli, and in Examples 1-(3) to 1-(4), sardines It was found to be harmless in a bioassay using . Example 2 An experiment similar to Example 1 was conducted by supplying solid sodium chloride to the oxidation tank instead of supplying seawater in the apparatus shown in FIG. The same results as in Example 1 were obtained.

[Brief explanation of drawings]

FIGS. 1A and 1B show an example of the arrangement of each element of the device of the present invention. FIG. 2 shows a specific example of an apparatus for carrying out the present invention. In the figure, 1...excrement oxidation tank, 2...excess tank, 3...electrolytic tank,
4... DC power supply, 5... Sodium chloride supply means, 6
...Reducing agent supply means.

Claims (1)

[Claims] 1. Sodium chloride is added to the excrement, a circulation path is formed for the added liquid, and an electrolysis section is provided in the circulation path to generate sodium hypochlorite to remove the excrement. A method for treating excrement, which comprises oxidizing the liquid, and then detoxifying the sodium hypochlorite remaining in the oxidized liquid using a reducing agent before discharging it. 2. The method for treating excrement according to claim 1, wherein the addition of sodium chloride is carried out by adding seawater. 3. An excrement oxidation tank having an excrement introduction part and a treatment liquid discharge part, a circulation path including the oxidation tank, a means for introducing common salt provided in the circulation path, and a means for electrolyzing the salt,
and a detoxification treatment means by reducing sodium hypochlorite remaining in the liquid in the oxidation tank. 4. The excrement treatment device according to claim 3, wherein the introduction of common salt is the introduction of seawater.