Domestic garbage and domestic sewage coordinated treatment system and treatment method

Abstract

The present invention discloses a system for the coordinated treatment of domestic garbage and domestic sewage, wherein the mud outlet at the bottom of the concentration tank is connected to a sewage dewatering workshop, and the drain outlet at the top of the concentration tank is connected to a sewage treatment pipeline; one end of the sewage treatment pipeline is connected to the water outlet of a condenser, and the other end is connected to a biochemical treatment structure, which includes an SBR aerobic reaction tank and an SBBR reactor; the mud outlet at the bottom of the biochemical treatment structure is connected to the concentration tank, and the drain outlet at the top of the biochemical treatment structure is connected to a circulating water replenishment system through a water outlet pipeline; the water outlet of the condenser is connected to a power generation system. This method solves the problem that when anaerobic ammonia oxidation is performed in sewage treatment in the prior art, an external heat source needs to be set up to maintain the water temperature, which results in high energy consumption, and the sludge generated by sewage treatment occupies a large area, and the subsequent treatment energy consumption is high, resulting in a large amount of heat waste. By jointly setting up garbage incineration power generation and sewage treatment, the residual energy is used to achieve heat exchange, which effectively reduces energy consumption.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental protection, and in particular relates to a system and method for coordinating the treatment of domestic garbage and domestic sewage. Background Art

[0002] At present, the domestic garbage and domestic sewage generated by residents are treated by a divide-and-conquer approach, that is, separately building landfills, waste incineration power plants and domestic sewage treatment plants. This decentralized construction and separate treatment technology has poor economic efficiency and large energy waste. The sewage temperature changes completely with the ambient temperature during sewage treatment. When the water temperature is low, the biochemical treatment effect of sewage deteriorates. Especially the "anaerobic ammonia oxidation" process, which saves more than 60% of oxygen supply compared to traditional full-process nitrification, basically does not require an external carbon source, and can reduce 15% of sludge production. In this type of process, the most suitable temperature for anaerobic ammonia oxidizing bacteria is 30~35℃. The stringent requirements for water temperature are an important factor restricting the large-scale engineering application of "anaerobic ammonia oxidation", an efficient and low-carbon water treatment technology. The existing technology often adopts the method of independently adding external heat sources to maintain temperature to ensure that the temperature of the raw sewage water is within the range of 30-35°C, which consumes a lot of energy. The sludge generated in the sewage treatment process occupies a large area if it is disposed of separately. If drying and reduction are adopted, the investment in the source of hot steam is large and the operating efficiency is low. If incineration is adopted, it is necessary to build an incinerator, which increases investment and wastes the heat generated by the incineration of sludge. Therefore, it is necessary to design a coordinated treatment technology for domestic waste and domestic sewage to solve the above problems. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a system and method for the coordinated treatment of domestic waste and domestic sewage. The method solves the problem in the prior art that when anaerobic ammonia oxidation is carried out in sewage treatment, an external heat source needs to be set up to maintain the water temperature, which results in high energy consumption, and the sludge generated by sewage treatment occupies a large area, and the subsequent treatment energy consumption is high, resulting in a lot of heat waste.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] The domestic garbage and domestic sewage coordinated treatment system comprises a concentrating tank, wherein the mud outlet at the bottom of the concentrating tank is connected to the sewage dewatering workshop, and the drain outlet at the top of the concentrating tank is connected to the sewage treatment pipeline; one end of the sewage treatment pipeline is connected to the water outlet of the condenser, and the other end is connected to the biochemical treatment structure, and the biochemical treatment structure comprises an SBR aerobic reaction tank and an SBBR reactor; the mud outlet at the bottom of the biochemical treatment structure is connected to the concentrating tank, and the drain outlet at the top of the biochemical treatment structure is connected to the circulating water supply system through a water outlet pipeline; the water outlet of the condenser is connected to the power generation system.

[0006] Preferably, the power generation system includes a make-up water pipeline, one end of which is connected to the condenser, and the other end is connected to the boiler; the make-up water pipeline is connected in sequence from one end of the condenser to a condensate polishing device, a low-pressure heater, a deaerator, a boiler make-up water pump group and a high-pressure heater; the boiler exhaust end is connected to the steam turbine and the generator set.

[0007] Preferably, the exhaust steam pipelines of the steam turbine and the generator set are connected to the condenser.

[0008] Preferably, the flue gas pipeline of the boiler is connected to the flue gas heater, a heat exchange branch is connected in parallel to the sewage treatment pipeline, and the heat exchange branch is connected to the flue gas heater for heating; an electric valve is provided between the inlet and outlet of the heat exchange branch.

[0009] Preferably, the circulating water replenishment system includes a cooling tower, which is connected to the condenser through a circulating water pipe, and a circulating water pump is connected to the circulating water pipe; the water is discharged to the outside through a drain outlet at the bottom of the cooling tower.

[0010] Preferably, the separated and recovered liquid from the sewage dehydration workshop is returned to the concentration tank, and the solid and gaseous combustibles from the sewage dehydration workshop are used for combustion in the boiler.

[0011] Preferably, a method for treating a domestic waste and domestic sewage coordinated treatment system comprises the following steps:

[0012] S1, combine the waste-to-energy plant with the sewage treatment plant, and use the solid waste and exhaust gas from sewage treatment as fuel supplement for the waste-to-energy plant;

[0013] S2, the pre-treated domestic sewage enters the condenser for heat exchange, the heated sewage raw water enters the sewage treatment pipeline, the water temperature is maintained at 30~35℃, and then sent to the SBR aerobic reaction tank for aerobic reaction to remove COD and phosphorus; the sewage raw water after the reaction enters the SBBR reactor for short-range denitrification coupled anaerobic ammonia oxidation process; the waste gas generated by the reaction is sent to the boiler through the pipeline for incineration; the tail water after the reaction is connected to the cooling tower through the pipeline;

[0014] S3, the residual sludge produced by the reaction in step S2 is discharged into a concentration tank for concentration, and the supernatant after concentration is discharged into a sewage treatment pipeline for re-reaction; the concentrated sludge after concentration is discharged into a sludge dehydration workshop for dehydration, and the separated liquid after dehydration is discharged into a concentration tank for re-treatment, and the separated concentrated sludge is sent to a crushing device, mixed with domestic garbage and crushed, and used as fuel for the boiler;

[0015] S4, the tail water treated in step S2 is first cooled by a cooling tower, and then pumped into a condenser through a circulating water pipe and a circulating water pump to perform heat exchange with boiler water used for power generation in a water supply pipeline;

[0016] S5, in step S4, the exhaust steam after power generation by the steam turbine and the generator set enters the condenser through the exhaust steam pipeline, and the exhaust steam is cooled by the domestic sewage raw water in the sewage treatment pipeline and the circulating water in the circulating water pipe; the cooled boiler water is sequentially finely treated, heated and deoxygenated through the feed water pipeline, and then sent to the boiler through the boiler feed water pump group for heating and vaporization, and the vaporized steam enters the steam turbine and the generator set to generate electricity, and the exhaust steam after power generation repeats the above cycle process;

[0017] S6, the high-temperature flue gas generated by boiler combustion is connected to the flue gas heater through a pipeline. The heat exchange branch arranged on the sewage treatment pipeline bypasses the inside of the flue gas heater, and heats the sewage raw water on the sewage treatment pipeline to the temperature required for the reaction by exchanging heat with the flue gas heater.

[0018] Furthermore, the dehydrated sludge has a moisture content of 50-60%.

[0019] Furthermore, the treated domestic sewage can be used to replenish the circulating water system, thermal system, process water, etc. in the waste-to-energy production process. Excess tail water is discharged into the water body as ecological water replenishment.

[0020] Furthermore, domestic sewage pretreatment includes sewage treatment screen interception and primary sedimentation treatment; the pretreated waste is also sent to the crushing mechanism to be crushed together with sludge and domestic garbage, and then enters the boiler for incineration.

[0021] Furthermore, multiple electric valves are provided on the pipeline, which are connected to the intelligent temperature control system of the waste incineration generator set according to the sewage water temperature, sewage water volume and the output of the waste generator set.

[0022] The beneficial effects of the present invention are:

[0023] 1. In this system, garbage and sewage are managed in a coordinated manner, on the one hand, waste is used to treat waste, and on the other hand, electricity is produced, which is low-carbon and high-efficiency;

[0024] 2. In this system, waste gas and sludge waste from sewage treatment are used as supplementary fuel for incineration power generation, which saves energy consumption costs. On the other hand, the residual heat from incineration power generation can be used as a heat source to maintain the temperature of the sewage raw water in sewage treatment, thereby avoiding the need to set up an additional separate heat source for sewage treatment, further saving energy consumption; the low temperature of the sewage raw water and the low temperature of the subsequent tail water after cooling can provide a heat exchange medium for the condensation of exhaust steam; the treated tail water can also be used as circulating water and boiler water makeup, further realizing the recycling of water resources; the entire system cooperates with each other between power generation and sewage treatment, rationally utilizes the residual energy in each link, and effectively realizes cost control; and the system structure itself is easy to implement and maintain, and has strong feasibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the present invention;

[0026] The reference numerals in the figure are: concentration tank 1, sewage dehydration workshop 2, sewage treatment pipeline 3, condenser 4, SBR aerobic reaction tank 5, SBBR reactor 6, feed water pipeline 7, boiler 8, condensate polishing device 9, low-pressure heater 10, deaerator 11, boiler feed water pump group 12, high-pressure heater 13, steam turbine, generator set 14, exhaust steam pipeline 15, flue gas pipeline 16, flue gas heater 17, heat exchange branch 18, cooling tower 19, circulating water pipe 20, circulating water pump 21. DETAILED DESCRIPTION

[0027] like Figure 1 A system for coordinated treatment of domestic waste and domestic sewage includes a concentration tank, wherein a mud outlet at the bottom of the concentration tank is connected to a sewage dewatering workshop, and a drain outlet at the top of the concentration tank is connected to a sewage treatment pipeline; one end of the sewage treatment pipeline is connected to the water outlet of a condenser, and the other end is connected to a biochemical treatment structure, and the biochemical treatment structure includes an SBR aerobic reaction tank and an SBBR reactor; the mud outlet at the bottom of the biochemical treatment structure is connected to the concentration tank, and the drain outlet at the top of the biochemical treatment structure is connected to a circulating water supply system through a water outlet pipeline; the water outlet of the condenser is connected to a power generation system.

[0028] Preferably, the power generation system includes a make-up water pipeline, one end of which is connected to the condenser, and the other end is connected to the boiler; the make-up water pipeline is connected in sequence from one end of the condenser to a condensate polishing device, a low-pressure heater, a deaerator, a boiler make-up water pump group and a high-pressure heater; the boiler exhaust end is connected to the steam turbine and the generator set.

[0029] Preferably, the exhaust steam pipelines of the steam turbine and the generator set are connected to the condenser.

[0030] Preferably, the flue gas pipeline of the boiler is connected to the flue gas heater, a heat exchange branch is connected in parallel to the sewage treatment pipeline, and the heat exchange branch is connected to the flue gas heater for heating; an electric valve is provided between the inlet and outlet of the heat exchange branch.

[0031] Preferably, the circulating water replenishment system includes a cooling tower, which is connected to the condenser through a circulating water pipe, and a circulating water pump is connected to the circulating water pipe; the water is discharged to the outside through a drain outlet at the bottom of the cooling tower.

[0032] Preferably, the separated and recovered liquid from the sewage dehydration workshop is returned to the concentration tank, and the solid and gaseous combustibles from the sewage dehydration workshop are used for combustion in the boiler.

[0033] Preferably, a method for treating a domestic waste and domestic sewage coordinated treatment system comprises the following steps:

[0034] S1, combine the waste-to-energy plant with the sewage treatment plant, and use the solid waste and exhaust gas from sewage treatment as fuel supplement for the waste-to-energy plant;

[0035] S2, the pre-treated domestic sewage enters the condenser for heat exchange, the heated sewage raw water enters the sewage treatment pipeline, the water temperature is maintained at 30~35℃, and then sent to the SBR aerobic reaction tank for aerobic reaction to remove COD and phosphorus; the sewage raw water after the reaction enters the SBBR reactor for short-range denitrification coupled anaerobic ammonia oxidation process; the waste gas generated by the reaction is sent to the boiler through the pipeline for incineration; the tail water after the reaction is connected to the cooling tower through the pipeline;

[0036] S3, the residual sludge produced by the reaction in step S2 is discharged into a concentration tank for concentration, and the supernatant after concentration is discharged into a sewage treatment pipeline for re-reaction; the concentrated sludge after concentration is discharged into a sludge dehydration workshop for dehydration, and the separated liquid after dehydration is discharged into a concentration tank for re-treatment, and the separated concentrated sludge is sent to a crushing device, mixed with domestic garbage and crushed, and used as fuel for the boiler;

[0037] S4, the tail water treated in step S2 is first cooled by a cooling tower, and then pumped into a condenser through a circulating water pipe and a circulating water pump to perform heat exchange with boiler water used for power generation in a water supply pipeline;

[0038] S5, in step S4, the exhaust steam after power generation by the steam turbine and the generator set enters the condenser through the exhaust steam pipeline, and the exhaust steam is cooled by the domestic sewage raw water in the sewage treatment pipeline and the circulating water in the circulating water pipe; the cooled boiler water is sequentially finely treated, heated and deoxygenated through the feed water pipeline, and then sent to the boiler through the boiler feed water pump group for heating and vaporization, and the vaporized steam enters the steam turbine and the generator set to generate electricity, and the exhaust steam after power generation repeats the above cycle process;

[0039] S6, the high-temperature flue gas generated by boiler combustion is connected to the flue gas heater through a pipeline. The heat exchange branch arranged on the sewage treatment pipeline bypasses the inside of the flue gas heater, and heats the sewage raw water on the sewage treatment pipeline to the temperature required for the reaction by exchanging heat with the flue gas heater.

[0040] Furthermore, the dehydrated sludge has a moisture content of 50-60%.

[0041] Furthermore, the treated domestic sewage can be used to replenish the circulating water system, thermal system, process water, etc. in the waste-to-energy production process. Excess tail water is discharged into the water body as ecological water replenishment.

[0042] Furthermore, domestic sewage pretreatment includes sewage treatment screen interception and primary sedimentation treatment; the pretreated waste is also sent to the crushing mechanism to be crushed together with sludge and domestic garbage, and then enters the boiler for incineration.

[0043] Furthermore, multiple electric valves are provided on the pipeline, which are connected to the intelligent temperature control system of the waste incineration generator set according to the sewage water temperature, sewage water volume and the output of the waste generator set.

[0044] Embodiment 2:

[0045] In the specific implementation, first of all, the technical route and process plan are preliminarily selected based on external conditions such as the amount of domestic sewage, the amount of domestic waste treatment, environmental protection requirements, and meteorological conditions.

[0046] Secondly, based on the amount of domestic sewage, the inlet and outlet temperatures of sewage, the amount of condensation of the turbine, etc., the cooling ratio of the circulating water system is designed under the condition that the outlet temperature of domestic sewage under adverse environmental meteorological conditions in summer is <37°C (the cooling ratio cannot be determined according to the cold end optimization method of traditional garbage power generation units).

[0047] Then, when the amount of domestic sewage is large and the ambient temperature is low, the water temperature of the domestic sewage is adjusted by reducing the amount of circulating water and using flue gas auxiliary heating to ensure that the temperature of the sewage entering the biological treatment unit is within the range of 30~35℃ throughout the year.

[0048] Thirdly, the circulating water pump adopts variable frequency control to ensure that the pump speed is automatically adjusted according to daily temperature changes, unit output, sewage inflow, etc., and the water temperature of domestic sewage is controlled by regulating the circulating water volume.

[0049] Secondly, a regulating tank is set up before entering the biochemical pool (whether to set up this structure depends on the specific circumstances of the project) to ensure that the sewage entering the biochemical pool is homogeneous, uniform in quantity and temperature.

[0050] Again, after the domestic sewage is treated to meet the standards, part of it is sent to the power plant, part of it is used for power generation and consumption, and part of it meets the standards and is discharged externally.

[0051] Finally, the sludge produced during the domestic sewage treatment process is sent to the boiler for combustion after deep dehydration when the moisture content reaches 50~60%, and the heat generated is used to generate electricity.

[0052] The above-mentioned embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A system for the coordinated treatment of domestic waste and sewage, characterized by: The invention comprises a concentration tank (1), wherein the bottom mud outlet of the concentration tank (1) is connected to a sewage dewatering workshop (2), and the top drainage outlet of the concentration tank (1) is connected to a sewage treatment pipeline (3); one end of the sewage treatment pipeline (3) is connected to the water outlet of a condenser (4), and the other end is connected to a biochemical treatment structure, and the biochemical treatment structure comprises an SBR aerobic reaction tank (5) and an SBBR reactor (6); the bottom mud outlet of the biochemical treatment structure is connected to the concentration tank (1), and the top drainage outlet of the biochemical treatment structure is connected to a circulating water supply system through a water outlet pipeline; the water outlet of the condenser (4) is connected to a power generation system; the power generation system comprises a water supply pipeline (7), one end of the water supply pipeline (7) is connected to the condenser (4), and the other end is connected to The boiler (8) is connected; the feed water pipeline (7) is connected in sequence from one end of the condenser (4) to a condensate polishing device (9), a low-pressure heater (10), a deaerator (11), a boiler feed water pump group (12) and a high-pressure heater (13); the exhaust end of the boiler (8) is connected to the steam turbine and the generator set (14); the exhaust steam pipeline (15) of the steam turbine and the generator set (14) is connected to the condenser (4), the flue gas pipeline (16) of the boiler (8) is connected to the flue gas heater (17), and a heat exchange branch (18) is connected in parallel to the sewage treatment pipeline (3), and the heat exchange branch (18) is connected to the flue gas heater (17) for heating; an electric valve is arranged between the inlet and outlet of the heat exchange branch (18).

2. The system for coordinating the treatment of domestic waste and domestic sewage according to claim 1 is characterized by: The circulating water replenishment system comprises a cooling tower (19), the cooling tower (19) being connected to the condenser (4) via a circulating water pipe (20), the circulating water pipe (20) being connected to a circulating water pump (21); a drainage outlet at the bottom of the cooling tower (19) discharges water to the outside.

3. The system for coordinating the treatment of domestic waste and domestic sewage according to claim 1 is characterized by: The separated and recovered liquid in the sewage dehydration workshop (2) is returned to the concentration tank (1), and the solid and gaseous combustibles in the sewage dehydration workshop (2) are used for combustion in the boiler (8).

4. The method for treating domestic waste and domestic sewage in a coordinated treatment system according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1, combine the waste-to-energy plant with the sewage treatment plant, and use the solid waste and exhaust gas from sewage treatment as fuel supplement for the waste-to-energy plant; S2, the pre-treated domestic sewage enters the condenser (4) for heat exchange, and the heated sewage raw water enters the sewage treatment pipeline (3), where the water temperature is maintained at 30-35°C, and then is sent to the SBR aerobic reaction tank (5) for aerobic reaction to remove COD and phosphorus; the sewage raw water after the reaction enters the SBBR reactor (6) for short-range denitrification coupled anaerobic ammonia oxidation process; the waste gas generated by the reaction is sent to the boiler (8) through a pipeline for incineration; the tail water after the reaction is connected to the cooling tower (19) through a pipeline; S3, the residual sludge produced in the reaction in step S2 is discharged into a concentration tank for concentration, and the supernatant after concentration is discharged into a sewage treatment pipeline (3) for re-reaction; the concentrated sludge after concentration is discharged into a sludge dewatering workshop (2) for dehydration, and the separated liquid after dehydration is discharged into a concentration tank (1) for re-treatment, and the separated concentrated sludge is sent to a crushing device, mixed with domestic waste and crushed, and used as fuel for a boiler (8); S4, the tail water treated in step S2 is first cooled by a cooling tower (19), and then pumped into a condenser (4) through a circulating water pipe (20) and a circulating water pump (21) to perform heat exchange with boiler water used for power generation in a water supply pipeline (7); S5, in step S4, the exhaust steam after power generation by the steam turbine and the generator set (14) enters the condenser (4) through the exhaust steam pipeline (15), and is cooled by using the domestic sewage raw water in the sewage treatment pipeline (3) and the circulating water in the circulating water pipe (20); the cooled boiler water is sequentially finely treated, heated and deoxygenated through the feed water pipeline (7), and then sent to the boiler (8) through the boiler feed water pump group (12) for heating and vaporization, and the vaporized steam enters the steam turbine and the generator set (14) for power generation, and the exhaust steam after power generation repeats the above cycle process; S6, the high-temperature flue gas generated by the combustion of the boiler (8) is connected to the flue gas heater (17) through a pipeline, and the heat exchange branch (18) provided on the sewage treatment pipeline (3) bypasses the inside of the flue gas heater (17) and heats the sewage raw water on the sewage treatment pipeline (3) to a temperature required for the reaction by exchanging heat with the flue gas heater (17).

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