JP2001157898A - Method for treating waste water from waste disposal plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perfectly prevent secondary environmental pollution without complicated treatment or an inexpensive equipment by further treating waste water after treatment discharged heretofore and to reduce the number of apparatuses to shorten a treatment time. SOLUTION: Waste water is passed through a water amount adjusting process due to an adjusting tank and a biological treatment process due to a biological treatment tank or a chemical treatment tank or a chemical treatment process and a filtering process due to a filter tank or a filter device from a waste disposal plant to obtain a treated dischargeable waste water which is, in turn, supplied to a combustion and evaporation apparatus to evaporate only moisture and a residual substance is recovered to be returned to final disposal site.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for treating wastewater from a waste disposal site.

[0002]

2. Description of the Related Art Waste disposal sites are facilities that return waste generated from human activities to the earth by land reclamation. If the waste is reclaimed as it is, harmful substances contained in the waste Since there is a concern that the water may diffuse into the soil and cause environmental destruction, a method of preventing water leakage by laying a water shielding sheet or the like is adopted.

[0003] In such a landfill disposal site, it is necessary to treat seepage water and leachate such as rainwater. Such wastewater treatment is performed by providing a collection pipe such as a leachate drainage pipe at the bottom of the disposal site. FIG. 7 shows an example of such wastewater treatment which is conducted outside the site. In FIG. 7, reference numeral 1 denotes a landfill as a waste disposal site, from which rainwater infiltration water and leachate are collected by a collection pipe 2 through a collection pipe. The water collecting tank 2 is provided with a level sensor, and when the water level exceeds a certain level, the pump is automatically pumped up to the flow rate adjusting tank 3 by the installed pump.

The flow control tank 3 leads to a sedimentation tank such as a sedimentation tank to perform a treatment in a primary treatment coagulation sedimentation treatment tank 4. The primary treated wastewater is used as a chemical treatment tank and is subjected to contact aeration biological treatment. Chemical treatment is performed in a secondary treatment denitrification coagulation sedimentation tank 5 in which nitrification denitrification and coagulation precipitation are performed together. The wastewater introduced from landfill 1 is BOD 250ppm, SS 250pp
m, COD 250 ppm, TN 250 ppm, ph 8-10
After this secondary treatment denitration coagulation sedimentation treatment 5 is performed,
BOD is changed from 250ppm to 20ppm, and 92% treatment is performed.
From 100ppm to 10ppm, 90% is removed.

[0005] The secondary treated wastewater is sent to a neutralization tank 6,
It is neutralized by a neutralizing agent. After the neutralization treatment, it is temporarily stored in the water pumping tank 7 or the storage tank, sent to the filtration device 8 while adjusting the flow rate, and is subjected to a process of removing a small amount of suspended substances through a filtering agent. SS changes from 30 ppm to 6 ppm, and 80% is removed.

[0006] The filtered water that has passed through the filtration device 8 is sent to the active adsorption device 9 where various organic compounds are adsorbed and removed. BOD is less than 10ppm, SS is less than 10ppm, COD is less than 10ppm
Hereinafter, TN will be 10 ppm or less. The waste water that has been actively adsorbed is sent to a backwash tank 10, and then a sterilizing agent is injected in a sterilizing tank 11 to be disinfected, and the coliforms become 3,000 or less / 1 cm3. The above is the outline of the treatment, and the treated water is generally discharged.

The excess sludge from the sedimentation tank in the first treatment coagulation and sedimentation treatment 4 and the second treatment denitration coagulation and sedimentation 5 is supplied to a sludge concentration tank.
13 and sent to the sludge storage tank 14, and the concentrated sludge is further dewatered.
It is sent to 15 to perform a dewatering process, taken out through the dewatered cake hopper 16 and returned to the landfill.

The wastewater treatment for industrial waste treatment has been described above. In addition to such treatment, wastewater treatment at a final waste disposal site includes treatments as shown in FIGS. 8 shows a case mainly composed of non-burnable refuse, FIG. 9 shows a case mainly composed of incinerated ash, and FIG. 10 shows a case mainly composed of incineration residue and non-combustible refuse. Although a detailed description thereof will be omitted, the contact tank is a biological treatment tank that performs biological treatment in place of the chemical treatment such as the secondary treatment denitration coagulation sedimentation 5 or the like.

[0009] The above is the outline of the current processing, and the treated water is discharged. However, it is assumed that there is a residual substance such as a salt compound as a component that cannot be collected or removed even by such a treatment, and when discharged, the residue accumulates in, for example, the roots of rice, and the rice rots.

[0010] Therefore, the inventor of the present invention previously treats the treated wastewater, which has been conventionally discharged, further to recover salt compounds and other harmful substances, thereby eliminating the need for complicated treatment and expensive equipment. Invented and applied for a water treatment method and facility capable of completely preventing secondary pollution (Japanese Patent Application No. 10-98757, Japanese Patent Application Laid-Open No. 11-290835), and obtained a patent (Patent No. 2999)
No. 748].

This is shown in FIG. 4, but the wastewater that can be discharged after the usual water treatment is heated by a heat exchanger, then cooled and vaporized by an evaporator, and only water is evaporated. The wastewater is sent to a drain concentrating tank, and the concentrated wastewater is sent to a heat exchanger to evaporate only the water and collect it as a residue, thereby completely preventing secondary pollution.

[0012] In addition to a water collecting tank 2 for introducing rainwater infiltration water and leachate from a landfill 1, a flow control tank 3, a primary treatment coagulation sedimentation treatment tank 4, a secondary treatment A denitration / coagulation sedimentation tank 5, a neutralization tank 6, a water pumping tank 7, a filtration device 8, an active adsorption device 9, a backwash tank 10, a sterilization tank 11, and the like are provided.
In the figure, reference numeral 12 denotes a treatment water tank for guiding wastewater that can be discharged in the sterilization tank 11, and reference numerals 17 and 22 denote heat exchangers.

In the figure, 19 is a heat storage hot water tank, 20 is an evaporator,
Heated wastewater from the heat exchanger 17 is introduced into the heat storage hot water tank 19, and the evaporator 20 is a cooling tower, which cools and evaporates the hot water from the heat storage hot water tank 19 to evaporate only water. The drain concentrating tank 21 is for introducing concentrated waste water after evaporating water from the evaporator 20, and is provided with a heat exchanger.
Send to 22.

As a water treatment method, rainwater infiltration water and leachate from the landfill 1 are introduced into the water collecting tank 2 by a water collecting pipe, and the water is automatically pumped up to the flow adjusting tank 3 by a pump. The primary treatment coagulation and precipitation treatment 4 is performed from 3 and the secondary treatment denitration coagulation and precipitation 5 is further performed. The wastewater subjected to the secondary treatment is sent to the neutralization tank 6, and after being subjected to the neutralization treatment, is temporarily stored in the water pumping tank 7 or the storage tank, and is sent to the filtration device 8 while adjusting the flow rate, where the filtering agent is passed therethrough. The filtered water is sent to an active adsorption device 9 where various organic compound substances are adsorbed and removed, and the active adsorbed wastewater is sent to a backwash tank 10 and then to a sterilization tank.
Inject sterilizer at 11 and disinfect.

The drained water thus treated and allowed to be discharged is stored in the treated water tank 12, introduced into the heat exchanger 17 from the treated water tank 12, and heated to produce hot water. The heated wastewater is sent to a heat storage hot water tank 19, further sent to an evaporator 20, where it is cooled and vaporized, only water is evaporated, and then sent to a drain concentration tank 21. Assuming that the waste water from the heat storage hot water tank 19 to the evaporator 20 is, for example, about 37 ° C., the evaporator 20 cools the vapor by about 5 ° C., ie, about 35 ° C., and evaporates.

The waste water concentrated in the drain concentration tank 21 is sent to a heat exchanger 22 for reheating, and only water is evaporated to recover salt 23 as a residual substance. It is sent to another processing plant.

In order to prevent pollution, the exhaust duct of the combustion furnace 18 introduces combustion exhaust gas to a smoke exhaust cleaning device 24,
Further, the gas is introduced into the exhaust tower 25 from the smoke exhaust cleaning device 24 and exhausted to the atmosphere. Exhaust gas from the combustion furnace 18 is treated by a flue gas cleaning device 24 so as not to emit harmful substances such as Hcl, SOX, NOX, and dioxin, and is discharged to the atmosphere.

The filtration tank 26 is for filtering and removing various suspended substances such as a deodorizing device renewal solution, a flue gas cleaning renewal solution, and a filtration device backflow drainage. The residue in the filtration tank 26 is returned to the original landfill.

[0019]

[Problems to be Solved by the Invention] Thus, Patent No. 2999
In the water treatment method and facility of No. 748, wastewater that can be discharged after water treatment undergoes a two-stage process of heating with a heat exchanger and evaporating by cooling and evaporating with an evaporator. As for the device, part of the treated water from the treated water tank flows to the lid of the combustion furnace and moves laterally to heat it, and the other part flows to a meandering pipe attached to the exhaust duct of the furnace to heat it. It consists of a combination of two devices: a heat exchanger that heats water, a hot water heat storage tank that stores hot water in the heat exchanger, and an evaporator that cools and evaporates hot water from the hot water heat storage tank.

The use of two devices, a heat exchanger and an evaporator, in such a two-stage process has the advantage that the processing is reliable and that each device does not need to be large-scale. However, there is a problem in terms of processing time and space efficiency of equipment installation.

An object of the present invention is to eliminate the disadvantages of the above-mentioned conventional example, and to further treat the treated wastewater, which has been conventionally discharged, to recover salt compounds and other harmful substances. It is an object of the present invention to provide a method for treating wastewater from a waste disposal site, which can completely prevent secondary pollution without using complicated facilities, and can reduce the number of devices and the processing time.

[0022]

In order to achieve the above object, the present invention firstly provides a process for adjusting the amount of water discharged from a waste disposal site using a regulating tank, a biological treatment tank using a biological treatment tank or a chemical treatment tank. Alternatively, the gist of the present invention is to directly evaporate waste water that can be discharged after water treatment in which a chemical treatment step, a filtration tank or a filtration device is used for a filtration step, by a combustion evaporator.

Secondly, the wastewater from the waste disposal site is subjected to a water amount adjustment step using an adjustment tank, a biological treatment step using a biological treatment tank or a chemical treatment tank, a chemical treatment step, or a filtration step using a filtration tank or a filtration device. The gist of the present invention is to evaporate only water from the wastewater that can be discharged after the water treatment by a combustion evaporator, collect residual substances, and bury them in a final disposal site.

Thirdly, the wastewater from the waste disposal site is subjected to a water amount adjustment step using an adjustment tank, a biological treatment step using a biological treatment tank or a chemical treatment tank, a chemical treatment step, or a filtration step using a filtration tank or a filtration device. The gist of the present invention is to mix wastewater that can be discharged after water treatment with sludge, burn and evaporate it in an incinerator, collect residual materials, and bury them at a waste disposal site.

Fourth, the gist of the invention is that the evaporated water is liquefied and reused as hot water.

According to the first aspect of the present invention, the treated wastewater that is normally discharged is treated by evaporating water, so that salt compounds and other harmful substances are not released, and environmental protection is prevented. In addition to the above, it has been possible to directly evaporate directly with a combustion evaporator, instead of the conventional two-step process of heating with a heat exchanger and evaporating by cooling and evaporating with an evaporator. In one step.

According to the second aspect of the present invention, in addition to the above-mentioned effects, by collecting the residual substance and burying it in the final disposal site, the salt compound and other harmful substances are not discharged, thereby ensuring the reliability. And wastewater treatment can be performed more efficiently.

According to the third aspect of the present invention, wastewater that can be discharged after water treatment is mixed with sludge, and this is burned and evaporated in an incinerator, and the residual material is recovered to dispose of waste. By burying in the place, sludge treatment and wastewater treatment can be performed in the same work process, and the treatment can be rationalized.

According to the present invention, it is possible to use hot water as a by-product, use in a greenhouse (vegetables, fruits, flowers) in an agricultural business, and in aquaculture (rainbow trout, turtle, tilapia) in a fishery business. In the amusement business, it can be used for Kurhauss, pools, etc.

[0030]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a flow chart showing a first embodiment of a method for treating wastewater from a waste disposal site according to the present invention, in which the same components as those in FIG.

First, the equipment constituting the water treatment facility of the present invention
The equipment will be described. In addition to the water collecting tank 2 for introducing rainwater infiltration water and leachate from the landfill 1, a flow control tank 3, a primary treatment coagulation sedimentation treatment tank 4, Next treatment denitration coagulation sedimentation tank 5, neutralization tank 6, pumping tank 7, filtration device 8, active adsorption device 9, backwashing tank 10, sterilization tank 11
This is the same as the conventional example.

This is an example, and the drainage treatment at the preceding stage includes the treatments shown in FIGS. 4 to 10 and other treatments. In any case, the water amount adjusting step using the adjusting tank, the biological processing step using the biological processing tank or the chemical processing tank, the chemical processing step, and the filtration step using a filtration tank or a filtration device are appropriately combined.

In the figure, reference numeral 12 denotes a treated water tank for guiding wastewater that can be discharged in the sterilizing tank 11. In the figure, reference numeral 27 denotes an incinerator, which is located below the incinerator 27 as shown in FIGS.
A submerged combustion type waste liquid incinerator equipped with 27a is suitable, and the incinerator 27 has a waste liquid spray nozzle 27b, a combustion air inlet 27c, an auxiliary combustion burner 27d, and a frame detector 27e,
The cooling recovery can 27a is a downcomer tube 27f and a wear 27
g, an exhaust gas outlet 27h, and a liquid overflow port 27i.

In this submerged combustion system, the high-temperature combustion gas generated by combustion is injected into the liquid at once, and the liquid is brought into direct contact with the combustion gas bubbles to effectively transfer heat and absorb the combustion gas components. Do. The cooling and collecting can 27a has a function as an effective cooling device for the combustion gas, and also as an excellent collecting or collecting device for high-temperature dust due to the contained inorganic component.

Next, the wastewater treatment method of the present invention using such equipment will be described. In the present invention, a water treatment that is usually performed is performed as a previous step. In the present embodiment, the water treatment shown in FIG.

That is, rainwater infiltration water and leachate from the landfill 1 are introduced into the water collecting tank 2 by a water collecting pipe, and are automatically pumped up to the flow regulating tank 3 by a pump.
, A first treatment coagulation sedimentation treatment 4 is performed, and a second treatment denitration coagulation sedimentation treatment 5 is further performed.

The secondary treated wastewater is sent to the neutralization tank 6,
After the neutralization treatment, it is once stored in a pumping tank 7 or a storage tank, and sent to a filtration device 8 while adjusting the flow rate. Here, filtered water that has passed through a filtering agent is sent to an active adsorption device 9 where various organic substances are filtered. The wastewater from which the compounds have been adsorbed and removed and the active adsorption has been carried out is sent to the backwash tank 10, and then a disinfectant is injected into the disinfection tank 11 for disinfection.

According to the present invention, the drained water treated as described above and allowed to be discharged is stored in the treated water tank 12,
From the wastewater spray nozzle 27b. In this way, the waste water is sprayed into a fine mist during the high-temperature spraying and evaporated.

A flue gas cleaning device 24 is connected to an exhaust gas outlet 27h of the cooling / recovery can 27a to introduce combustion exhaust gas into the flue gas cleaning device 24. Exhausted to the atmosphere. Exhaust gas from the combustion furnace 18 is treated by a flue gas cleaning device 24 so as not to emit harmful substances such as Hcl, SOX, NOX, and dioxin, and is discharged to the atmosphere.

The excess sludge from the sedimentation tank in the first treatment coagulation / sedimentation treatment 4 and the second treatment denitration coagulation / sedimentation 5 is supplied to the sludge concentration tank.
13 and sent to the sludge storage tank 14, and the concentrated sludge is further dewatered.
It is sent to 15 to perform a dewatering process, taken out through the dewatered cake hopper 16 and returned to the landfill.

Further, a deodorizing device 28 is provided, into which the odors of the water collecting tank 2, the flow rate adjusting tank 3, the primary treatment coagulation sedimentation treatment tank 4, and the secondary treatment denitration coagulation sedimentation treatment tank 5 are introduced.
The waste from here is renewal liquid for deodorizing equipment, renewal liquid for flue gas cleaning,
The filter is returned to the flow control tank 3 through a filter tank 26 for filtering and removing various suspended substances such as backflow drainage.

FIG. 2 shows a second embodiment of the present invention. Although an incinerator 37 is not shown, it burns and incinerates ordinary waste 30. Spray the wastewater and evaporate the wastewater with the heat of incineration. The residue that is not evaporated is combined with the residue from incineration of the waste 30 and is carried out and returned to the original landfill.

As a third embodiment, the incinerator 37 shown in FIG. 2 comprises a primary combustion chamber 37a, a secondary combustion chamber 37b and a tertiary combustion chamber 37c as shown in FIG. The treated water from the treated water tank 12 flows and evaporates. In the figure, 40 is a combustion burner, 41 is a combustion air supply pipe, 42 is an ash removal device,
43 is a gas intake facility, and 49 is an exhaust duct.

The combustion furnace 37 mainly uses heavy oil as fuel, but may use wood chips, paper chips, or the like as another alternative fuel as a heat source. Then, in order to prevent pollution, the exhaust duct 49 of the combustion furnace 37 introduces the combustion exhaust gas to the smoke exhaust cleaning device 24, and is further introduced from the smoke exhaust cleaning device 24 to the exhaust tower 25 and exhausted to the atmosphere. . In FIG. 7, 45 is a circulating water tank arranged in the flue gas washer 24, and 46 is a circulating water tank.
, An induction fan for sending exhaust gas to the exhaust tower 25, 47 is a caustic soda tank, and 48 is an active adsorbent charging device.

The combustion exhaust gas from the combustion furnace 37 is supplied to a flue gas cleaning device.
At 24, a treatment is carried out so as not to emit harmful substances such as Hcl, SOX, NOX, dioxin and the like and released to the atmosphere.

As a fourth embodiment, as shown in FIG. 4, wastewater from the treated water tank 12 is led to a sludge concentration tank 50, where the sludge 51
And stored in a sludge storage tank 52 and then burnt and evaporated in an incinerator 53.

As the sludge 51, 1) sewage sludge, 2) construction sludge, 3) organic sludge, 4) inorganic sludge, 5) red sludge, 6) excess sludge by the activated sludge method, 7) pulp waste liquid sludge, 8) Wastewater treatment sludge from industries using animal and plant raw materials, 9) Building pit sludge, 10) Carbide sludge, 11) Muddy sludge remaining after treatment of factory wastewater such as calcium carbonate sludge, and mud from various manufacturing industries And the like.

As the incinerator 53, a fixed-bed furnace, a fluidized-bed furnace, a stoker furnace, a rotary kiln, a rotary furnace, and the like are suitable.

By mixing the wastewater from the treatment water tank 12 with the sludge 51 in this way, the sludge 51 can be diluted, the sludge particles can be made finer when the sludge 51 is burned, and the drying time can be shortened.

The incineration residue 29 in the incinerator 53 is collected and returned to the original waste disposal site.

Further, as a fifth embodiment, the first to fourth embodiments
In addition to the embodiment, the water generated in the incinerators 27, 37, 53 and the like is cooled, liquefied, and reused as hot water.

In the field of hot water use, hot water can be used as a by-product. In the agricultural business, it is used for greenhouses (vegetables, fruits, flowers). Eel),
In the amusement business, Kurhaus and pools are possible.

[0053]

As described above, the method for treating wastewater from a waste disposal site according to the present invention, the wastewater that has been conventionally discharged, is further treated to recover salt compounds and other harmful substances. In addition, secondary pollution can be completely prevented without complicated processing and expensive equipment, and the number of devices can be reduced and the processing time can be shortened.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a first embodiment of a method for treating wastewater from a waste disposal site according to the present invention.

FIG. 2 is a flowchart showing a second embodiment of the method for treating wastewater from a waste disposal site according to the present invention.

FIG. 3 is a flowchart illustrating a method for treating wastewater from a waste disposal site according to a fourth embodiment of the present invention.

FIG. 4 is a flowchart showing a conventional example.

FIG. 5 is an explanatory diagram of an incinerator used in the first embodiment.

FIG. 6 is an explanatory diagram of an incinerator and the like used in a third embodiment.

FIG. 7 is a flowchart showing a second conventional example.

FIG. 8 is an explanatory view showing a third conventional example.

FIG. 9 is an explanatory diagram showing a fourth conventional example.

FIG. 10 is an explanatory diagram showing a fifth conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Landfill 2 ... Water collecting tank 3 ... Flow control tank 4 ... Primary treatment coagulation sedimentation treatment tank 5 ... Secondary treatment denitration coagulation sedimentation tank 6 ... Neutralization tank 7 ... Pumping tank 8 ... Filtration apparatus 9 ... Active adsorption apparatus 10 ... Backwash tank 11… Disinfection tank 12… Treatment water tank 13… Sludge concentration tank 14… Sludge storage tank 15… Dehydrator 16… Dehydration cake hopper 17… Heat exchanger 18… Combustion furnace 19… Heat storage hot water tank 20… Evaporation device 21… Drain condensing tank 22 ... Heat exchanger 23 ... Salt recovery 24 ... Smoke exhaust cleaning device 25 ... Exhaust tower 26 ... Filter tank 27 ... Incinerator 27a ... Cooling and collecting can 27b ... Waste liquid spray nozzle 27c ... Combustion air inlet 27d ... Auxiliary combustion burner 27e ... Frame detector 27f ... Downcomer tube 27g ... Wear 27h ... Exhaust gas outlet 27i ... Liquid overflow port 28 ... Deodorizer 29 ... Incineration residue 30 ... Waste 37 ... Incinerator 37a ... Primary combustion chamber 37b ... Secondary combustion chamber 37c ... tertiary combustion chamber 39 ... lid 40 ... combustion burner 41 ... combustion Gas supply pipe 42 ... Ash removal device 43 ... Gas intake equipment 44 ... Exhaust tube 45 ... Circulating water tank 46 ... Induction fan 47 ... Caustic soda tank 48 ... Active adsorbent charging device 49 ... Exhaust duct 50 ... Sludge concentration tank 51 ... Sludge 52 ... Sludge storage tank 53 ... Incinerator

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[Procedure amendment]

[Submission date] January 18, 2000 (2000.1.1)
8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

In the figure, 19 is a heat storage hot water tank, 20 is an evaporator,
Is to heat accumulating hot water tank 19 is introduced warmed waste water from the heat exchanger 17, evaporator 20 the hot water from the thermal storage hot water tank 19 is cooled vaporized, evaporate water only. Drain concentration tank 21
Is for introducing concentrated wastewater after evaporating water from the evaporator 20, and sends it to the heat exchanger 22.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 9/00 502 C02F 9/00 502D 502H 502P 504 504A 504E 1/12 1/12

Claims (4)

[Claims] Claims: 1. Water treatment in which wastewater from a waste disposal site is subjected to a water amount adjustment step by an adjustment tank, a biological treatment step by a biological treatment tank or a chemical treatment tank, a chemical treatment step, a filtration step by a filtration tank or a filtration device. A method for treating wastewater from a waste disposal site, comprising directly evaporating waste water that can be discharged later using a combustion evaporator. 2. Water treatment in which wastewater from a waste disposal site is subjected to a water amount adjustment step by an adjustment tank, a biological treatment step by a biological treatment tank or a chemical treatment tank, a chemical treatment step, or a filtration step by a filtration tank or a filtration device. A method for treating wastewater from a waste disposal site, comprising: evaporating only water in a wastewater that can be discharged later using a combustion evaporator, collecting residual substances, and burying the waste in a final disposal site. 3. Water treatment in which wastewater from a waste disposal site is subjected to a water amount adjustment step by an adjustment tank, a biological treatment step by a biological treatment tank or a chemical treatment tank, a chemical treatment step, or a filtration step by a filtration tank or a filtration device. Wastewater that can be discharged later is mixed with sludge, which is burned and evaporated in an incinerator, and the residual substances are collected and buried in the waste disposal site. Processing method. 4. The method for treating wastewater from a waste disposal site according to claim 1, wherein the evaporated water is liquefied and reused as hot water.