CN214457453U - Leachate biochemical section treatment system for efficient denitrification - Google Patents

Abstract

The utility model provides a biochemical section processing system of filtration liquid of high-efficient denitrogenation, the biochemical section processing system of filtration liquid of high-efficient denitrogenation includes: the primary A/O unit is used for carrying out primary denitrification on the percolate; and the secondary A/O unit is positioned behind the primary A/O unit and is used for carrying out secondary denitrification on the percolate treated by the primary A/O unit. The utility model discloses use traditional sedimentation tank to replace current milipore filter to carry out mud-water separation, fully consider energy saving and consumption reduction, reduce the working costs, adopt the technology of investment minimum, working costs reasonable, easy to maintain and operation management.

Description

Leachate biochemical section treatment system for efficient denitrification

Technical Field

The utility model belongs to the technical field of filtration liquid is handled, in particular to biochemical section processing system of filtration liquid of high-efficient denitrogenation.

Background

The ammonia nitrogen of the landfill leachate stock solution is generally about 1000-2000 mg/L. When the nitrogen content in the sewage is high, microorganisms are easy to be poisoned, and the biochemical treatment effect can be influenced. The general biological denitrification process is schematically shown as follows:

the method specifically comprises the following steps: (1) ammoniation reaction: under the action of ammoniation bacteria, organic nitrogen is decomposed and converted into ammoniacal nitrogen, the process is called as ammoniation process, and the ammoniation process is easy to carry out;

(2) nitration reaction: the nitration reaction is completed by aerobic autotrophic microorganisms, and in an aerobic state, NH4+ is converted into NO2- (nitrite) by utilizing an inorganic carbon source (such as carbon dioxide), and then is oxidized into NO3- (nitrate);

(3) and (3) denitrification reaction: the denitrification reaction is a process that nitrite nitrogen and nitrate nitrogen are reduced into gaseous nitrogen (N2) by denitrifying bacteria under the anoxic (different from anaerobic) state;

denitrifying bacteria are heterotrophic microorganisms, mostly facultative bacteria, and in an anoxic state, oxygen in nitrate is used as an electron acceptor, and organic matters (organic matters in sewage) are used as an electron donor to provide energy and be stably oxidized.

At present, the biochemical treatment process of percolate in the market mainly adopts MBR (anoxic A tank, aerobic O tank and ultrafiltration membrane, which are collectively called MBR). Wherein the A tank and the O tank can remove organic matters, simultaneously carry out denitrification through nitrification-denitrification, and carry out sludge-water separation through an ultrafiltration membrane. After MBR, nanofiltration and ultrafiltration are usually added to further remove nitrate ions in the system.

Currently, an external tubular ultrafiltration membrane is commonly used in the market, in order to keep the normal operation of the membrane, the external circulation amount is required to be more than 20 times, cross-flow filtration is also required in the membrane, the flow rate in the membrane is ensured to be 4-5 m/s, so that the sludge is prevented from being deposited on the surface of the membrane, and the energy consumption required by backflow is very large (taking the treatment capacity of 200t/d as an example, only the power of an external circulating pump is up to 90 kW). Although a built-in ultrafiltration membrane can be selected and used, the energy consumption is lower than that of an external ultrafiltration membrane, the ultrafiltration membrane is frequently cleaned and is easy to block, and the inconvenience is brought to the operation. Whether the ultrafiltration system is an external ultrafiltration system or an immersed ultrafiltration system, MBR has high energy consumption and is easy to block, so that the system is unstable.

Meanwhile, in order to keep the hydraulic retention time of sewage in the tank A, the tank capacity of the MBR system is relatively large (the hydraulic retention time of 8-10 days is mostly needed), but the MBR system has no positive effect on nitrification and denitrification reactions, and the total nitrogen removal effect is very poor (actually measured, the total nitrogen of effluent of the conventional MBR system still reaches hundreds of milligrams or thousands of milligrams per liter). At present, more and more areas require zero discharge of sewage, in order to remove the total nitrogen, the total nitrogen can only depend on the filtration of subsequent reverse osmosis membranes (the reverse osmosis membranes mainly intercept monovalent salt), and reverse osmosis concentrated solution (namely intercepted substances) becomes a new pollution source.

SUMMERY OF THE UTILITY MODEL

The utility model discloses not enough and the defect to prior art exists, the utility model aims to provide a biochemical section processing system of filtration liquid of high-efficient denitrogenation.

The utility model provides a technical scheme that technical problem adopted as follows:

a leachate biochemical segment treatment system for efficient denitrification, the leachate biochemical segment treatment system comprising:

the primary A/O unit is used for carrying out primary denitrification on the percolate; and

and the secondary A/O unit is positioned behind the primary A/O unit and is used for performing secondary denitrification on the percolate treated by the primary A/O unit.

In the above-mentioned biochemical section treatment system for leachate with high efficiency denitrification, as a preferred embodiment, the biochemical section treatment system for leachate further comprises a denitrification adjustment unit disposed between the primary a/O unit and the secondary a/O unit, wherein the leachate treated by the primary a/O unit enters the denitrification adjustment unit, and the denitrification adjustment unit is used for mixing the leachate from the primary a/O unit; preferably, the water outlet of the secondary a/O unit is communicated with the denitrification adjustment unit, and a part of the leachate treated by the secondary a/O unit flows back into the denitrification adjustment unit to enter the secondary a/O unit again for treatment (i.e. a part of the leachate treated by the secondary a/O unit flows back into the denitrification adjustment unit and is mixed with the leachate entering the denitrification adjustment unit from the primary a/O unit, and then flows into the secondary a/O unit for treatment).

In the biochemical treatment system for leachate with high efficiency denitrification, as a preferred embodiment, the primary a/O unit sequentially comprises a primary a tank, a primary O tank and a primary sedimentation tank according to the flow direction of the leachate; the first-stage A pool is an anoxic reactor for denitrification reaction; the primary O tank is an aerobic reactor for nitration reaction, the leachate overflows from an overflow port of the primary A tank and enters the primary O tank, and then the leachate flows to the primary sedimentation tank through a liquid outlet of the primary O tank by gravity through a water outlet pipeline; preferably, a part of sludge in the primary sedimentation tank flows back to the primary A tank through a pump.

In the above-mentioned leachate biochemical treatment system with high efficiency denitrification, as a preferred embodiment, a stirring assembly is arranged in the primary tank a.

In the above-mentioned biochemical section treatment system for leachate with high efficiency denitrification, as a preferred embodiment, the primary tank a comprises a plurality of partitions; preferably, the plurality of partitions are connected in series, and the percolate flows into the next partition after being treated by one partition and then flows into the primary O pool from the last partition through the overflow hole; a plurality of the first-stage A pools are separated and connected in series, so that the problems that the first-stage A pools are overlarge and have dead water areas and the like can be avoided; preferably, the stirring assembly is disposed in each of the partitions.

In the above-mentioned leachate biochemical section treatment system with high efficiency denitrification, as a preferred embodiment, the primary O tank includes a main aerobic reaction zone and a pre-settling zone communicated with the main aerobic reaction zone, and the pre-settling zone is used for pre-settling sludge; preferably, the pre-settling zone is 1/12-1/9 of the volume of the whole primary O pool; preferably, the bottom of the pre-settling zone is a slope with an inclination angle of 40-50 degrees; preferably, a chain plate mud and slag scraping machine is arranged in the pre-settling zone.

In the above-mentioned leachate biochemical section treatment system with high efficiency denitrification, as a preferred embodiment, the main aerobic reaction zone in the primary O tank is provided with a flow guiding partition wall; preferably, the flow guiding partition wall can be used for improving the flow condition (hydraulic condition) of the percolate so that the percolate in the primary O pool is fully mixed and a dead water area is avoided.

In the above-mentioned leachate biochemical treatment system with high denitrification efficiency, as a preferred embodiment, a blower device and an aeration device are arranged in the main aerobic reaction zone of the primary O tank, so that the primary O tank is in an aerobic state.

In the above biochemical percolate treatment method, as a preferred embodiment, in the step 1), the primary sedimentation tank is a middle-in and middle-out radial-flow sedimentation tank; preferably, a mud scraper is arranged in the primary sedimentation tank to prevent sludge from depositing at the bottom of the tank.

In the biochemical section treatment system for leachate with high-efficiency denitrification, as a preferred embodiment, the secondary a/O unit sequentially comprises a secondary a tank for denitrification, a secondary O tank for nitrification and a final sedimentation tank according to the flow direction of the leachate, an overflow port of the secondary a tank is communicated with the secondary O tank, and a liquid outlet of the secondary O tank is communicated with the final sedimentation tank; preferably, a sludge outlet of the final sedimentation tank is respectively communicated with the first-stage A tank and the second-stage A tank, and part or all of sludge in the final sedimentation tank flows back to the first-stage A tank and the second-stage A tank through a pump.

In the above-mentioned leachate biochemical treatment system with high efficiency denitrification, as a preferred embodiment, a stirring assembly is arranged in the secondary tank A.

In the above biochemical treatment system for leachate with high denitrification efficiency, as a preferred embodiment, the secondary a tank includes a plurality of partitions, preferably, the partitions are connected in series, and the leachate after treatment by one partition flows into the next partition and then flows into the secondary O tank from the last partition through the overflow port of the secondary a tank; a plurality of the second-stage A pools are separated and connected in series, so that the problems that the second-stage A pools are overlarge and have dead water areas and the like can be avoided; preferably, the stirring assembly is disposed in each of the partitions.

In the above-mentioned leachate biochemical section treatment system with high-efficiency denitrification, as a preferred implementation, a denitrification dosing unit is arranged between the denitrification adjustment unit and the secondary a tank, and is used for adding nutrients required by denitrifying bacteria; preferably, the denitrification dosing unit is a denitrification dosing tank, and a dosing pipeline is arranged in the denitrification dosing tank.

In the above-mentioned biochemical section treatment system for leachate with high efficiency denitrification, as a preferred embodiment, the biochemical section treatment system for leachate further comprises a sand filtration unit, the sand filtration unit is communicated with the water outlet of the secondary a/O unit, and the leachate treated by the secondary a/O unit enters the sand filtration unit to filter impurities of the leachate.

In the above-mentioned biochemical section processing system of leachate of high-efficient denitrogenation, as a preferred embodiment, biochemical section processing system of leachate still includes back flush wastewater reservoir, and sand filtration unit backwash water flows into in the back flush wastewater reservoir (sand filtration system backwash water is the waste water that forms for washing the sand filtration system who uses a period of time), the delivery port of back flush wastewater reservoir with denitrification adjusting unit intercommunication, water in the back flush wastewater reservoir is beaten back through the pump denitrification adjusting unit handles, in order to get rid of the pollutant in the sand filtration system backwash water and the used pipeline of this kind of processing mode is shorter.

Compared with the prior art, the utility model discloses following beneficial effect has:

(1) the utility model discloses a design is separated to be used for adding the medicine groove and the second grade A pond that add medicine before setting up the second grade AO pond, cultivates the effectual, high-quality mud that concentration height and settlement performance are good of denitrogenation and carries to first section AO system. And a denitrification adjusting tank is additionally arranged in front of the second section of tank A, and microorganisms are selected by adjusting the environment in the tank, so that effective denitrification is performed in the whole system, and the effect of removing total nitrogen is good.

(2) The utility model discloses set up the preliminary sedimentation district at first section O pond (one-level O pond) back end, can ensure the sludge settling effect. The utility model provides a preliminary sedimentation district can play the preliminary sedimentation effect, and it is mutually supported with one-level sedimentation tank for get into the better separation of mud and water. (3) The utility model discloses use traditional sedimentation tank to replace current milipore filter to carry out mud-water separation, fully consider energy saving and consumption reduction, reduce the working costs, adopt the technology of investment minimum, working costs reasonable, easy to maintain and operation management.

(4) The utility model discloses all set up agitated vessel in two-stage AO's "A" section, improve the activity of denitrifying bacteria, make the reaction more abundant.

(5) The utility model discloses mud in the final sedimentation tank not only flows back to the second grade A pond of this section, also flows back simultaneously in the one-level A pond, utilizes second grade A pond and carbon source for example methyl alcohol to tame out the activated sludge of good property like this, carries for entire system.

(6) The utility model discloses the one-level sedimentation tank also can carry out the mud backward flow, and the mud discharge is arranged from the one-level sedimentation tank, and the final sedimentation tank does not arrange mud, can make the good mud make full use of that forms after carbon source (for example methyl alcohol) adjustment, and here also is different from two sections AO systems of tradition.

Drawings

FIG. 1 is a structural diagram of a biochemical treatment system for leachate for high-efficiency denitrification according to the present invention;

FIG. 2 is a schematic diagram of the partition provided in the primary A tank;

FIG. 3 is a schematic view of a baffle wall disposed in the primary O-tank;

FIG. 4 is a schematic diagram of the partition provided in the secondary A tank.

Wherein, 1 is a first-stage A tank, 2 is a first-stage O tank, 3 is a first-stage sedimentation tank, 4 is a denitrification adjusting tank, 5 is a denitrification dosing tank, 6 is a second-stage A tank, and 61,62 and 66 are separated by the second-stage A tank; 7 is a secondary O tank, 8 is a final sedimentation tank, 9 is a sand filtration unit, 10 is a backwashing wastewater storage tank, 11 is a sludge concentration tank, 12 is an overflow hole, 13 is a primary A tank separation, 14 is a flow guide partition wall, 15 is a pre-sedimentation area, and 16 is an overflow port.

Detailed Description

In order to highlight the objects, technical solutions and advantages of the present invention, the present invention will be further described with reference to the following embodiments, examples of which are provided by way of illustration rather than limitation of the present invention. The technical solution of the present invention is not limited to the following specific embodiments, but also includes any combination between the specific embodiments.

The utility model discloses in the preceding, the equal directional words such as back of using, it confirms according to the treatment order of filtration liquid or sewage or the order of flowing through, the precedence of the equipment that filtration liquid or sewage flowed through is the precedence of its processing promptly. The utility model discloses in, get into the utility model discloses biochemical section processing system's raw water is called filtration liquid, and later filtration liquid after each unit or the equipment treatment in the system also can be called the play water of corresponding unit or equipment.

The utility model provides a leachate biochemical section treatment system and method with high-efficiency denitrification. The utility model discloses the system is fit for handling sewage or filtration liquid that ammonia nitrogen content is more than 1000mg/L, is particularly suitable for handling the landfill leachate that ammonia nitrogen content is about 1000 ~ 2000 mg/L.

The biochemical section process of the utility model is described as follows:

leachate is pretreated (large floating objects, settled sand and the like are intercepted) and treated by anaerobic treatment (the anaerobic treatment refers to a type of process in sewage treatment, because the concentration of leachate pollutants is high, the direct entering of a subsequent AO system can make the tank volume very large and uneconomical, and the concentration of sludge in the anaerobic process can reach very high and can be treated roughly firstly and then enter a subsequent AO tank for continuous treatment), and then the leachate flows into a primary A tank, and the primary A tank is divided into different partitions (for example, 2-6 partitions or more partitions) according to different treatment amounts. A blender is positioned in each partition. The first-stage A tank receives the return sludge of the first-stage sedimentation tank and the second-stage sedimentation tank at the same time. The first-level A pool is provided with a cover, and the percolate reacts under the anoxic condition. The residence time of the first-stage pool A is 8-14 h.

The water from the first-level A pool flows into the first-level O pool through an overflow port (or an overflow hole). The first-stage O pool comprises a main aerobic reaction zone and a pre-settling zone communicated with the main aerobic reaction zone. The main body aerobic reaction zone is partially opened, the middle part of the main body aerobic reaction zone is provided with a flow guide partition wall, and sewage is in a plug flow state in the flow guide partition wall, so that the flow of the sewage is increased, and the aerobic reaction efficiency is improved. The main aerobic reaction zone of the first-stage O tank is provided with a blower and an aeration air pipe and is in an aerobic state. The tail end of the first-stage O tank is provided with a pre-settling zone communicated with the main aerobic reaction zone, and the volume of the pre-settling zone is about 1/10 of the volume of the whole O tank. The retention time in the first-stage O tank is 5-8 days (including a pre-settling zone).

The pre-settling zone is used for pre-settling the sludge in the pre-settling zone. The bottom of the pre-settling area is a slope with an inclination angle of 45 degrees, and a chain plate is arranged in the pre-settling area to scrape mud and slag, so that the mud at the bottom of the pool and the scum on the surface of the pool can be more easily collected and conveyed to a mud concentration pool. The first-stage O tank is also internally provided with the reflux of the nitrified liquid, and the reflux ratio is 200%. The returned nitrified liquid enters a main aerobic reaction zone of the first-stage A pool.

The sludge concentration of the primary O tank is controlled to be 13000-15000 mg/L.

The effluent of the first-level O tank automatically flows into the first-level sedimentation tank from the pre-sedimentation zone through a pipeline, the front-end process is properly controlled, the sludge sedimentation performance is good, a part of sludge flows back to the tank A (realized by a pump), and the reflux ratio is 200-250% (the sludge reflux ratio refers to the ratio of the amount of the returned sludge to the amount of the treated water, for example, the treated water amount is 20m³The sludge reflux ratio is 200 percent, so the amount of the reflux sludge is 40m³/h)。

The first-level sedimentation tank is a radial-flow sedimentation tank with a middle inlet and a periphery outlet, and is provided with a mud scraper to prevent sludge from depositing at the bottom of the tank. When the sludge concentration is too high, sludge is discharged (conveyed to a sludge concentration tank by a sludge discharge pump).

The hydraulic retention time of the first-stage sedimentation tank is about 12 hours.

The effluent of the first-stage sedimentation tank is pumped to a denitrification adjusting tank. The denitrification adjusting tank regulates and controls the water quantity and the water quality entering the secondary A/O system. The hydraulic retention time is about 8-14 hours. The denitrification adjusting tank is provided with a cover and stirring equipment.

And pumping the sewage after the denitrification adjusting tank into a denitrification dosing tank. A dosing pipeline is arranged in the denitrification dosing tank, and nutrients (organic carbon sources such as methanol, glucose, sodium acetate, starch and the like; phosphoric acid is added at proper time to supplement a phosphorus source) required by denitrifying bacteria are added into the dosing tank.

And the sewage automatically flows into the second-level A pool from the denitrification dosing tank.

The residence time of the secondary A pool was about 15 h. A plurality of separation areas are arranged in the denitrification stirring tank (namely the second-level A tank), sewage flows through different partitions in sequence, and a stirrer is arranged in each partition. So that the sewage is fully mixed with the medicine added in the denitrification medicine adding tank. And sewage automatically flows into a second-stage O tank from the second-stage A tank, an aeration air pipe is arranged in the second-stage O tank to aerate the sewage, and the hydraulic retention time of the second-stage O tank is 12 hours. The sludge concentration of the secondary O tank is controlled to be 8000-12000 mg/L.

The sewage automatically flows into a final sedimentation tank from the secondary O tank, and the hydraulic retention time is 8 h. The final sedimentation tank is provided with a mud scraper to prevent the settled sludge from hardening at the bottom of the tank.

And part of sludge in the final sedimentation tank needs to flow back to a front-end A tank (namely a first-level A tank) with a reflux ratio of 200-250%, and part of sludge flows back to a second-level A tank with a reflux ratio of 100-150%.

And (4) the waste sludge in the primary sedimentation tank enters a sludge concentration tank for subsequent treatment.

The outlet water of the final sedimentation tank enters a sand filtration system, and the sand filtration system can filter impurities in the water as required as a security measure. The backwashing water of the sand filtration system is temporarily stored in a backwashing wastewater storage tank and pumped back to the denitrification adjustment tank by a pump for treatment. The subsequent treatment process can be additionally set according to the effluent requirement.

Referring to fig. 1, the utility model provides a biochemical section treatment system for leachate with high efficiency denitrification, which comprises a primary A/O unit for performing primary denitrification on the leachate and a secondary A/O unit for performing secondary denitrification on the leachate; and the leachate enters a secondary A/O unit for further denitrification after being subjected to denitrification by the primary A/O unit.

As a preferred embodiment, a denitrification adjustment unit is arranged between the primary a/O unit and the secondary a/O unit, the denitrification adjustment unit is preferably a denitrification adjustment tank 4, and the leachate treated by the primary a/O unit passes through the denitrification adjustment tank 4, so that the leachate flowing from the primary a/O unit in a period of time is mixed in the denitrification adjustment unit, thereby solving the problem that the leachate entering the secondary a/O unit in different periods of time has high concentration, especially nitrogen concentration; then the percolate enters a secondary A/O unit from the denitrification adjusting tank 4 to be treated; preferably, when the ammonia nitrogen content in the percolate is high and the nitrate nitrogen content entering the secondary AO unit is too high due to uncontrollable factors in the primary AO unit (in practice, the nitrate nitrogen concentration is greater than 800mg/L is used as a boundary), a part of the percolate treated by the secondary a/O unit flows back to the denitrification adjustment tank 4, the percolate returning from the secondary a/O unit in the denitrification adjustment tank 4 and the percolate entering the denitrification adjustment tank 4 from the primary a/O unit are mixed in the denitrification adjustment tank 4, so that the percolation concentration of the liquid nitrogen entering the secondary a/O unit is reduced, and then the percolate flows from the denitrification adjustment tank 4 to the secondary a/O unit, so that the percolate can be treated again by the secondary a/O unit.

As a preferred embodiment, a denitrification dosing unit is arranged between the denitrification adjusting unit and the secondary A pool and is used for adding nutrient substances required by denitrifying bacteria; preferably, the denitrification dosing unit is a denitrification dosing tank 5, effluent (i.e., leachate) of the denitrification adjustment tank is pumped into the denitrification dosing tank 5, a dosing pipeline is further arranged in the denitrification dosing tank 5, nutrients (organic carbon sources, such as methanol, glucose, sodium acetate, starch and the like) required by denitrifying bacteria are added into the denitrification dosing tank 5, and then the nutrients enter the secondary A/O unit through the denitrification dosing tank 5.

As a preferred embodiment, the primary A/O unit comprises a primary A pool 1, a primary O pool 2 and a primary sedimentation pool 3 in sequence according to the flowing direction of the percolate; the leachate overflows from an overflow port 16 of the primary A tank 1 and enters a primary O tank 2, and then the leachate flows to a primary sedimentation tank 3 through a liquid outlet of the primary O tank 2 by gravity through a water outlet pipeline; a part of sludge in the primary sedimentation tank 3 flows back to the primary A tank 1 through a pump; preferably, the first-stage A pool 1 is an anoxic reactor for denitrification reaction; the first-stage O tank 2 is an aerobic reactor for nitration reaction; preferably, the first-stage A pool is provided with a cover, and the percolate reacts under the anoxic condition;

preferably, referring to fig. 2, the primary a pool 1 includes a plurality of primary a pool partitions 13 connected in series, which is equivalent to the primary a pool 1 being divided into a plurality of partitions connected in series for avoiding the primary a pool from being too large to have a dead water area, and the leachate flows into the next partition after being treated by one partition, and then flows into the primary O pool 2 from the last partition through the overflow hole; namely, the water of the anaerobic water inlet pipe of the first-level A pool 1 enters the hole formed on the upper surface of the first-level A pool, flows to the other partition through the overflowing hole 12, and then flows to the first-level O pool 2 from the overflowing port 16. Preferably, a stirrer is arranged in each primary A pool partition 13 in the primary A pool 1;

referring to fig. 3, it is preferable that the primary O-tank is partially open, and a flow guide partition 14 is provided in the middle, in which sewage is in a push flow state, and the flow guide partition can be used to improve hydraulic conditions of leachate so that the leachate in the primary O-tank is sufficiently mixed to avoid a dead water region; preferably, the primary O tank 7 is provided with a blower and an aeration air pipe, and the primary O tank is in an aerobic state.

Preferably, the primary O-pool 7 comprises a main aerobic reaction zone and a pre-settling zone communicated with the main aerobic reaction zone, a flow guiding partition wall 14 is arranged in the middle of the main aerobic reaction zone, the arrangement direction of the flow guiding partition wall 14 is the same as the water flow direction, the number of the flow guiding partition walls 14 can be 1, 2 or more, and a plurality of flow guiding partition walls 14 are arranged in parallel. The baffle walls 14 are separated into different zones, and two adjacent zones are communicated. The tail end of the first-stage O tank 7 is provided with a pre-settling zone 15 for pre-settling sludge, and the volume of the pre-settling zone is about 1/10 of the volume of the whole O tank; preferably, the bottom of the pre-settling zone is a slope with an inclination angle of 45 degrees; preferably, a chain plate mud and slag scraping machine is arranged in the pre-settling zone; the sludge at the bottom of the tank and the scum on the surface of the tank can be more easily collected and conveyed to the sludge concentration tank.

Preferably, the primary sedimentation tank 3 is a radial-flow sedimentation tank with a middle inlet and a periphery outlet, and is provided with a mud scraper to prevent sludge from depositing at the bottom of the tank. When the sludge concentration is too high, sludge discharge is performed (to the sludge concentration tank 11 by a sludge discharge pump). And (4) the waste sludge in the primary sedimentation tank enters a sludge concentration tank for subsequent treatment.

As a preferred embodiment, the secondary A/O unit comprises a secondary A pool 6 for denitrification reaction, a secondary O pool 7 for nitration reaction and a final sedimentation pool 8 in sequence according to the flowing direction of percolate, the overflow port of the secondary A pool 6 is communicated with the secondary O pool 7, and the liquid outlet of the secondary O pool 7 is communicated with the final sedimentation pool 8; preferably, part of the sludge in the final sedimentation tank 8 is returned to the primary A tank 1 and the secondary A tank 6 by a pump.

Preferably, referring to fig. 4, the secondary a tank 6 comprises a plurality of secondary a tank partitions (61,62,66) connected in series, and the percolate treated by one secondary a tank partition 61 flows into the next secondary a tank partition 62 and then flows from the last secondary a tank partition 66 into the secondary O tank through the overflow port of the secondary a tank 6; a plurality of the secondary A pools are separated and connected in series, so that the problems that the secondary A pool 6 is overlarge and has a dead water area and the like can be avoided; preferably, the stirrer is arranged in each secondary A pool partition, so that the sewage is fully mixed with the medicines added into the secondary A pool 6 through the denitrification medicine adding groove 5.

Preferably, the final sedimentation tank 8 is provided with a mud scraper to prevent the settled sludge from hardening at the bottom of the tank.

Preferably, the leachate biochemical section treatment system for efficient denitrification further comprises a sand filtration unit 9 and a backwashing wastewater storage tank 10, effluent of the final sedimentation tank 8 enters the sand filtration unit 9, and the sand filtration unit 9 is used as a security measure and can filter impurities in water when needed. The backwashing water of the sand filtration unit is temporarily stored in the backwashing wastewater storage tank 10 and is pumped back to the denitrification adjustment tank by the pump for treatment, pollutants exist in the backwashing water and cannot be directly discharged, so the backwashing water needs to be pumped back to the system for treatment again.

The utility model discloses biochemical section processing system operation example

After the leachate is subjected to pretreatment (a grating intercepts large floating objects and settled sand) and anaerobic treatment (an anaerobic reactor cannot remove total nitrogen and can also increase ammonia nitrogen due to anaerobic reaction), the ammonia nitrogen entering a primary A/O unit (a primary A pool) is 2000mg/L and the total nitrogen is 2500mg/L after the anaerobic treatment;

after anaerobic treatment, leachate firstly flows into a primary A pool with 2 partitions, stays for 12 hours under stirring and anoxic conditions, then the effluent of the primary A pool (namely the leachate treated by the primary A pool) flows into a primary O pool in an aerobic state through an overflow port (the main part of the primary O pool is open, a flow guide partition wall is arranged in the middle, sewage is in a plug flow state in the primary O pool, the tail end of the primary O pool is provided with a pre-settling zone, the volume of the pre-settling zone is about 1/10 of the volume of the whole O pool), the retention time in the primary O pool is 6 days, the primary O pool is also provided with the reflux of nitrifying liquid, the reflux ratio is 200%, the refluxed nitrifying liquid (namely the sewage in the primary O pool) enters the primary A pool, the sludge concentration of the primary O pool is controlled at 14000mg/L, the effluent of the primary O pool automatically flows into the primary sedimentation pool through a pipeline from the pre-settling zone, and a part of settled sludge flows back to the primary A pool (realized by a pump), the reflux ratio is 200%; the hydraulic retention time of the primary sedimentation tank is 12 h. After the treatment of the first-stage A/O unit, the total nitrogen of the effluent of the first-stage A pool is 500 mg/L.

The effluent of the primary sedimentation tank is pumped to a denitrification adjustment tank under stirring conditions, wherein the denitrification adjustment tank regulates and controls the water quantity and the water quality entering the secondary A/O system (for example, percolate flowing from the primary sedimentation tank within a period of time is mixed in the denitrification adjustment unit, so that the problem of high and low percolate concentration, particularly nitrogen concentration, entering the secondary A/O unit within different periods of time can be solved), and the hydraulic retention time is about 8 hours.

And pumping the sewage (namely the percolate treated by the denitrification adjusting tank) behind the denitrification adjusting tank into a denitrification dosing tank. A dosing pipeline is arranged in the denitrification dosing tank at the same time, and nutrient substances (carbon source methanol and phosphoric acid are added in due time) required by denitrifying bacteria are added into the dosing tank.

The sewage automatically flows into a secondary A pool with 2 partitions from a denitrification dosing tank, the retention time in the secondary A pool is 15 hours, wherein the sewage and the medicines in the denitrification dosing tank are fully mixed under stirring; the sewage automatically flows into a secondary O tank from a secondary A tank, an aeration air pipe is arranged in the secondary O tank to aerate the sewage, and the hydraulic retention time of a denitrification aeration tank is 12 h; the sludge concentration of the secondary O tank is controlled to be 8000 mg/L; and the sewage automatically flows into a final sedimentation tank from the secondary O tank, the hydraulic retention time is 8 hours, and the final sedimentation tank is provided with a mud scraper to prevent settled sludge from hardening at the bottom of the tank.

And part of sludge in the final sedimentation tank needs to flow back to the first-level A tank at the front end, the reflux ratio is 200%, and the other part of sludge flows back to the second-level A tank, and the reflux ratio is 100%.

And (4) the waste sludge in the primary sedimentation tank enters a sludge concentration tank for subsequent treatment. The outlet water of the final sedimentation tank enters a sand filtration system, and the sand filtration system can filter impurities in the water as required as a security measure. The backwashing water of the sand filtration system is temporarily stored in a backwashing wastewater storage tank and pumped back to the denitrification adjustment tank by a pump for treatment.

In the leachate (namely sewage) treated by the method, the total nitrogen is 125mg/L, and the removal rate of the total nitrogen reaches 95 percent.

However, in current practical applications, in order to save the cost of chemicals, sewage plants often adopt a mode of adding raw water, but because the raw water of the inlet water may contain macromolecular organic matters, the treatment effect is not good. The simplest carbon source, such as methanol, is used in the process, with the decomposition products being carbon dioxide and water. Methanol has good effect as a carbon source, and activated sludge (namely sludge containing a large number of microorganisms) has good properties and is easy to settle, so that the method can realize the precipitation of high sludge concentration (about 10000 mg/L) only by adopting a sedimentation tank without using an ultrafiltration membrane with high energy consumption for sludge-water separation, although the medicament cost is increased, the equipment and operation cost is reduced, the total cost is not high, and the method has practical value.

The above embodiments describe the basic principles, main features and advantages of the present invention, and those skilled in the art should understand that the present invention is not limited by the above embodiments, and the description in the above embodiments and the description is only for illustration of the principles of the present invention, without departing from the scope of the present invention, the present invention can also have various changes and improvements, and these changes and improvements all fall into the protection scope of the present invention.

Claims (10)

1. The utility model provides a leachate biochemical segment processing system of high-efficient denitrogenation which characterized in that, leachate biochemical segment processing system includes:

the primary A/O unit is used for carrying out primary denitrification on the percolate; and

and the secondary A/O unit is positioned behind the primary A/O unit and is used for performing secondary denitrification on the percolate treated by the primary A/O unit.

2. The system of claim 1, wherein the leachate biochemical treatment system further comprises a denitrification adjustment unit disposed between the primary and secondary a/O units, the leachate treated by the primary a/O unit entering the denitrification adjustment unit, the denitrification adjustment unit being configured to mix the leachate from the primary a/O unit; and a water outlet of the secondary A/O unit is communicated with the denitrification adjusting unit, and a part of percolate treated by the secondary A/O unit flows back to the denitrification adjusting unit to enter the secondary A/O unit again for treatment.

3. The system of claim 2, wherein the primary a/O unit comprises a primary a tank, a primary O tank, and a primary settling tank in order according to the flow direction of the leachate; the first-stage A pool is an anoxic reactor for denitrification reaction; the primary O tank is an aerobic reactor for nitration reaction, the leachate overflows from an overflow port of the primary A tank and enters the primary O tank, and then the leachate flows to the primary sedimentation tank through a liquid outlet of the primary O tank by gravity through a water outlet pipeline; and part of sludge in the primary sedimentation tank flows back to the primary A tank through a pump.

4. The system of claim 3, wherein the primary A tank comprises a plurality of partitions connected in series, and wherein the percolate from one partition is treated and then flows into the next partition, and then from the last partition through the overflow port into the primary O tank, and wherein each partition is provided with a stirring assembly.

5. The system of claim 3, wherein the primary O tank comprises a main aerobic reaction zone and a pre-settling zone communicated with the main aerobic reaction zone, and the pre-settling zone is used for pre-settling sludge; the pre-settling zone is 1/12-1/9 of the volume of the whole primary O pool.

6. The system of claim 5, wherein the bottom of the pre-settling zone is a slope with an inclination angle of 40-50 °; a chain plate mud and slag scraping machine is arranged in the pre-settling area; a flow guide partition wall is arranged in a main aerobic reaction zone of the primary O tank; a blast device and an aeration device are arranged in the main aerobic reaction zone of the primary O tank; the first-stage sedimentation tank is a radial-flow sedimentation tank with a middle inlet and a peripheral outlet.

7. The system of claim 3, wherein the secondary A/O unit comprises a secondary A tank for denitrification reaction, a secondary O tank for nitrification reaction and a final sedimentation tank in sequence according to the flowing direction of the percolate, an overflow port of the secondary A tank is communicated with the secondary O tank, and a liquid outlet of the secondary O tank is communicated with the final sedimentation tank; and a sludge outlet of the final sedimentation tank is respectively communicated with the first-stage A tank and the second-stage A tank, and part or all of the sludge in the final sedimentation tank flows back to the first-stage A tank and the second-stage A tank through a pump.

8. The system of claim 7, wherein the secondary A tank comprises a plurality of partitions connected in series, and the percolate from one partition is treated and then flows into the next partition, and then from the last partition through the overflow of the secondary A tank into the secondary O tank; each partition is provided with a stirring component.

9. The system of claim 7, wherein a denitrification dosing unit is arranged between the denitrification adjusting unit and the secondary A tank and is used for adding nutrient substances required by denitrifying bacteria; the denitrification dosing unit is a denitrification dosing tank, and a dosing pipeline is arranged in the denitrification dosing tank.

10. The system of claim 7, wherein the leachate biochemical treatment system further comprises a sand filtration unit in communication with the water outlet of the secondary A/O unit, the leachate treated by the secondary A/O unit entering the sand filtration unit to filter impurities of the leachate; the percolate biochemical section treatment system further comprises a backwashing wastewater storage tank, backwashing water of the sand filtration unit flows into the backwashing wastewater storage tank, a water outlet of the backwashing wastewater storage tank is communicated with the denitrification adjusting unit, and water in the backwashing wastewater storage tank is pumped back to the denitrification adjusting unit for treatment.

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