JPH03131394A - Combined treatment method of refuse and raw sewage - Google Patents

Abstract

PURPOSE:To eliminate generation of coagulated sludge from a raw sewage treating process and to prevent treated water of raw sewage from being discharged by aerating raw sewage and treating it with filter membrane and further by evaporating and drying concentrated liquids having been treated by means of a reverse osmosis membrane at a waste gas cooling chamber of a refuse incinerator. CONSTITUTION:Raw sewage 7 is aerated in a scum removal raw sewage storage tank 9 to effect nitrification and denitrification, while slurry flowing out therefrom flows into a UF membrane of MF membrane separation device 10 to be separated to water 11 having passed through UF membrane and to separated sludge 12. Most of the sludge 12, i.e., return sludge 13, is returned to the tank 9 and the rest is sent as excessive sludge 14 to a dehydration process 16 together with scum 15 removed at a scum removal device 8. The water 11 is sent to a RO membrane device 19 to undergo reverse osmosis treatment to be separated to water having passed through RO membrane 20 and to concentrated liquid 21. The liquid 21 is fed into a gas cooling chamber 4 of a refuse incinerator 2 to be evaporated, wherein salts, organic matters are dried and captured at a dust collecting device 5 to be discharged together with dust 22 in incineration waste gas 3 and are abandoned together with burnt ash 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for extremely rationally combining and treating both garbage and human waste water (hereinafter simply referred to as human waste).

[Conventional technology]

A new technique for jointly processing both garbage and human waste is disclosed in Japanese Patent Laid-Open No. 63-200881. This technology involves biologically treating human waste, adding a flocculant to the biologically treated water, and then coagulating and separating the resulting treated water by spraying it into the gas cooling chamber of a waste incinerator for evapotranspiration disposal. Met.

[Problem to be solved by the invention]

However, it has been recognized that the above-mentioned conventional techniques have the following serious drawbacks and are far from ideal methods.

■ A large amount of hard-to-drain coagulated sludge is produced during the human waste treatment process [8I
(011)3 or Fe(Oil)z] is generated. A system for jointly processing garbage and human waste cannot be called ideal unless the system eliminates the generation of flocculated sludge from the human waste treatment process.

■ In reality, it very often happens that the amount of waste treated is less than the amount of human waste, but in this case, the entire amount of waste water treated is evaporated in the gas cooling room due to insufficient heat from the waste incineration exhaust gas. This would make it impossible to do so, and some of the human waste treated water would have to be discharged.

However, this human waste treated water is coagulated and separated water, which contains a high concentration of salt of 3,000 to 5,000 mg/e (CI), and environmental pollutants such as COD and chromaticity remain. Therefore, in addition to releasing water,
Even if it permeates underground, it will cause a significant increase in the salt concentration of groundwater and have a serious negative impact on plants. For waste incineration facilities, "no discharge of wastewater" is often required as a prerequisite during facility construction, so this situation is the biggest obstacle in the construction and operation of combined waste and human waste treatment facilities. Become.

The purpose of the present invention is to completely solve the above-mentioned drawbacks of the conventional technology, and specifically, to eliminate the generation of flocculated sludge from the human waste treatment process and to reduce the amount of waste and human waste to be processed. Our goal is to establish a rational system that can not only discharge water but also satisfy the "no drainage" or discharge conditions without any problems even in times of imbalance.

[Failure to solve the problem]

The present invention provides a process for nitrifying and denitrifying human waste water by aerating it in coexistence with nitrifying bacteria and denitrifying bacteria, and passing the effluent from the process through an ultrafiltration membrane or a microfiltration membrane. A process of membrane separation into solid content and membrane-permeated water, a process of further performing reverse osmosis treatment on the membrane-permeated water using a reverse osmosis membrane to separate it into membrane-permeated water and reverse osmosis concentrate, and a process in which the reverse osmosis concentrate is sent to a garbage incinerator. This is a combined treatment method for garbage and urine-based sewage characterized by the step of supplying the waste gas to an exhaust gas cooling chamber and evaporating it to dryness.

In the present invention, the reverse osmosis concentrate is evaporated to dryness in a waste incinerator.
A reverse osmosis concentrated liquid is sprayed in the form of a mist into the heat source of the waste incinerator, that is, the exhaust gas cooling chamber of the waste incinerator, and the concentrated liquid is evaporated using the heat of the exhaust gas cooling chamber. The form of evaporation treatment may be an open system or a closed system.

[Effect]

In the present invention having the above structure, the slurry liquid flowing out from the process of biologically nitrifying and denitrifying human waste is membrane-separated using an ultrafiltration membrane (hereinafter referred to as UF membrane), and most of the separated sludge is filtered through the nitrification process. It can be sent back to the denitrification process and the excess can be dehydrated as usual. In addition, the SS of UF membrane permeated water is zero, but the chromaticity and
A considerable amount of wastewater components such as COD and salt remain. This UF membrane permeated water is subjected to reverse osmosis treatment using a reverse osmosis membrane (hereinafter referred to as an RO membrane) to obtain highly purified RO membrane permeated water and a small amount of concentrated liquid in which the above-mentioned sewage components are concentrated. This concentrated liquid is stored in the exhaust gas cooling room of the waste incinerator (e.g., at a temperature of 700 to 750°C).
) and evaporate it.

The dehydrated separated water discharged when dewatering the excess sludge separated by the UF membrane is either returned to the biological nitrification and denitrification treatment process, the sludge removal urine storage tank, or the waste incinerator. The waste gas may be supplied to an exhaust gas cooling chamber for evaporation and evaporation, and the resulting dehydrated cake may be supplied to a waste incineration process and incinerated.

Therefore, the liquid that is directly discharged outside the system can be only the RO membrane permeated water, and since this RO membrane permeated water is highly treated to the same quality as rainwater, it can not only be discharged, but also underground. Infiltration disposal is possible without any problems, and no discharge is required into public water bodies, making it easy to satisfy the "no discharge of wastewater" condition.

〔Example〕

An embodiment of the present invention will be described with reference to FIG.
The present invention is not limited to this.

Garbage 1 is incinerated in a garbage incinerator 2, and incineration exhaust gas 3 flows out through a gas cooling chamber 4 to a dust collector 5 for the next step. 6 is incineration ash discharged from the garbage incinerator 2.

On the other hand, the human waste 7 is removed by a waste removal bag N8 such as a fine mesh screen, and then stored in the removed human waste storage tank 9. Conventionally, the filtered urine storage tank 9 literally only had the function of simply storing filtered urine and averaging the flow rate sent to the next process, but in the present invention, the filtered urine storage tank 9
One of the features is that nitrifying bacteria and denitrifying bacteria are artificially allowed to coexist within the system, and aeration is performed to simultaneously perform BOD removal and nitrogen removal.

In addition, a flocculant A such as a cationic polymer is used before the residue removal device 8.
Also suitable for the present invention is a means for coagulating and separating colloids and SS components in human waste 7 by adding .

Therefore, the slurry flowing out from the filtered urine storage tank 9 is
The water flows into the UP membrane or MF membrane separator 10 and is separated into clear UF membrane permeated water 11 containing completely zero SS and separated sludge 12.

Most of the separated sludge 12 separated by the tJF membrane separator 10 is recycled as return sludge 13 to the sludge storage tank 9, and the other part is recycled as surplus sludge 14 to the sludge 15 removed by the sludge bag W8. together with the dehydration step 16, where it is dehydrated,
The dehydrated cake 17 is supplied to the waste incinerator 2 and incinerated. Moreover, the dehydrated separated water 18 separated in the dehydration step 16 is
The waste is either returned to the human waste storage tank 9 or guided to the gas cooling chamber 4 of the waste incinerator 2 for evapotranspiration disposal.

Therefore, the UF membrane permeate water 11 (biological nitrification and denitrification treated water) with zero SS is guided to the RO membrane device 19 and undergoes reverse osmosis treatment, and a large amount of chromaticity remains in the UP membrane permeate water 11. , COD, PO43-1 salt, etc. are removed to a high degree, and the RO membrane permeated water 20 exhibits water quality equivalent to rainwater, and the concentrated liquid 21 (
The water amount is reduced to about 1/6 to 1/8 of the amount of water supplied to the RO membrane device 19).

The concentrated liquid 21 obtained by the RO membrane device 19 is sent to the garbage incinerator 2
The gas is supplied to the cooling chamber 4 where it is evaporated and disposed of, and the concentrated liquid 2
Salt, organic matter, etc. contained in the first and other substances become dry substances, are captured by the dust collector 5, are discharged together with the dust 22 in the incineration exhaust gas 3, and are disposed of together with the incineration ash 6.

In addition, since the RO membrane permeated water 20 from the RO membrane device 19 has a water quality equivalent to that of rainwater, it is possible to prevent the rainwater from penetrating into the ground by means such as deep wells, surface infiltration, or surface watering. It is easily possible to dispose of it by infiltrating it underground within the premises of the facility, without releasing it into public water bodies.

In addition, if there is enough heat in the waste incineration exhaust gas 3,
A part of the F membrane permeated water 11 can be supplied to the exhaust gas cooling chamber 4 and disposed of by evapotranspiration. In this case, the RO membrane device 1
Since the amount of water flowing into 9 is reduced, there is an effect that operating costs for RO membrane treatment can be saved.

Although biological nitrification and denitrification are preferably carried out in a storage tank as in the examples, they may be carried out afterwards as in the conventional manner.

〔Effect of the invention〕

As described above, according to the present invention, the following important effects can be achieved, and an ideal combined treatment system for garbage and human waste can be completed.

(2) Complete treatment can be achieved by omitting the flocculation separation step during the human waste treatment process, so the generation of flocculated sludge, which is difficult to dewater and is a nuisance in sludge treatment, can be reduced to zero.

■ Even when there is an imbalance between the amount of waste processed and the amount of urine processed,
Human waste treated water can be discharged without any problems, and it is possible to construct and operate a combined waste and human waste treatment facility that is extremely flexible in terms of operation. Furthermore, since the amount of water supplied to the RO membrane treatment can be automatically controlled according to enthalpy fluctuations in the exhaust gas from the waste incinerator, flexible operation is possible.

■ Since the amount of sludge generated from the human waste treatment process is reduced, co-combustion of waste and sludge becomes easier. This is because the calorific value of the sludge dehydrated cake is about 1-3 of the calorific value of garbage, so the less the sludge dehydrated cake, the better the combustibility during garbage incineration.

■ Compared to setting up separate facilities for treating human waste and garbage,
It requires fewer operation and management staff, resulting in a significant reduction in personnel costs.

■ Sludge incinerators, exhaust gas treatment equipment, etc. can be omitted from human waste treatment facilities, and construction costs and operating costs are significantly reduced.

■ If a new concept 0 is adopted in which a high concentration of nitrifying-denitrifying bacteria is artificially allowed to coexist in the sludge-removed urine storage tank and aeration is performed to perform the two functions of storage and nitrogen removal at the same time, the storage tank can It can prevent the occurrence of high concentration odor of hydrogen sulfide and prevent concrete corrosion due to hydrogen sulfide. In addition, a biological nitrification and denitrification tank (located after the sludge removal and sewage storage tank), which is essential in the conventional human waste treatment process, is also available.
This eliminates the need for construction costs and installation area, and as a result, a human waste treatment facility can be easily installed on the premises of a waste treatment facility.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a flowchart of the method for combined treatment of garbage and urine-based sewage according to the present invention. Explanation of symbols: 1: Garbage, 4: Gas cooling room, 7: Human waste, 9: Removal human waste storage tank, 10: UF membrane or MF membrane separation device, 11: UF membrane permeated water, 12: Separated sludge, 19: RO membrane device, 20:R
O-membrane permeated water, 21: Concentration and liquefaction Professor, Patent Attorney (8107) Kiyotaka Sasaki (and 3 others) ■ ■

Claims (1)

[Claims] 1. The process of nitrifying and denitrifying the wastewater by aerating it in coexistence with nitrifying bacteria and denitrifying bacteria, and removing the solid content of the effluent from the above process using an ultrafiltration membrane or a microfiltration membrane. The membrane-permeated water is further subjected to reverse osmosis treatment using a reverse osmosis membrane to separate it into membrane-permeated water and reverse osmosis concentrate, and the reverse osmosis concentrate is separated from waste gas from a waste incinerator. A method for the combined treatment of garbage and urine wastewater, which comprises the steps of supplying wastewater to a cooling room and evaporating it to dryness.