CN115448538A - Comprehensive treatment method for landfill leachate and kitchen waste water - Google Patents

Abstract

The invention relates to a comprehensive treatment method of landfill leachate and kitchen waste water, which comprises the following steps: s1: homogenizing and adjusting the landfill leachate and the kitchen waste water, inputting the garbage leachate and the kitchen waste water into a BBR (barium Broth-Barre) treatment unit for biochemical treatment, and degrading organic matters in the waste water by using bacillus to obtain primary treatment waste water; s2: inputting the primary treatment wastewater into a BDD treatment unit, and sequentially performing primary flocculation treatment, primary electrolysis treatment, secondary electrolysis treatment and secondary flocculation treatment to treat refractory organic matters and organic nitrogen to obtain secondary treatment wastewater; s3: and inputting the secondary treatment wastewater into a BBAF treatment unit, and treating nitrate nitrogen and residual organic matters in the secondary treatment wastewater to obtain produced water through anaerobic treatment, aerobic treatment and biochemical treatment of bacillus in sequence.

Description

A comprehensive treatment method for landfill leachate and kitchen waste water

technical field

The invention belongs to the technical field of waste water treatment, and in particular relates to a comprehensive treatment method for landfill leachate and kitchen waste water.

Background technique

Landfills and waste incineration plants will produce a large amount of landfill leachate in the process of waste treatment and disposal, and its chemical oxygen demand, biochemical oxygen demand, total nitrogen, and total phosphorus are relatively high. In addition, during the processing of kitchen waste and kitchen waste, high-concentration organic wastewater will be produced, which is usually treated by anaerobic digestion. The treated wastewater has the characteristics of high organic concentration, high total nitrogen, and high suspended solids. These two types of wastewater have similar characteristics, that is, high concentration of pollutants, poor biodegradability, and difficult to degrade. It is difficult to completely remove pollutants in wastewater by general biochemical treatment and advanced treatment measures, and the discharge of these wastewater into nature will not only seriously harm human beings. Health, but also cause eutrophication of water bodies. With the increasingly stringent wastewater discharge standards, the requirements for the treatment of landfill leachate and kitchen waste wastewater are also getting higher and higher.

At present, landfill leachate and kitchen waste wastewater are usually treated with biochemical combined with advanced treatment. Most of the pollutants are removed through biochemical process, and organic matter, total nitrogen, and total phosphorus are further removed through advanced treatment. Among them, the biochemical process mainly adopts anoxic-aerobic-MBR treatment process, and the advanced treatment mainly adopts membrane separation technologies such as nanofiltration and reverse osmosis. The MBR process has high construction costs, high energy consumption, complex operation and management, and poor stability; the membrane separation process is a physical separation that does not degrade pollutants, but only transfers them to the concentrate, and the concentrate produced has high salinity, The concentration of refractory organic matter is high, the treatment is difficult and the treatment cost is high.

In addition, an advanced treatment process combining Fenton advanced oxidation and biological aerated filter (BAF) can also be used. This technology has a high degree of degradation of pollutants and does not produce concentrated liquid, which has obvious advantages. Among them, the Fenton technology uses the Fenton reagent composed of Fe(II) ions and H ₂ O ₂ to generate hydroxyl radicals with strong oxidizing ability under acidic conditions with low pH to oxidize organic pollutants in wastewater and realize the removal of pollutants. Degradation removal. Due to the high alkalinity of the landfill leachate, it is necessary to add a large amount of strong acid to adjust the pH for advanced oxidation. After the reaction, alkali is added to adjust the pH to neutral, and at the same time, Fe(OH) ₃ chemical precipitation sludge is formed to form Secondary pollution, the salt content in the water has also increased. Because landfill leachate and kitchen waste water contain carbonates and other free radical scavengers, the utilization efficiency of hydroxyl radicals is reduced, and side reactions are significant. The above problems seriously affect the applicability of this technology application. How to achieve high-efficiency, low-cost, and clean removal of refractory organic matter is the focus and difficulty of current research.

Contents of the invention

In view of the above problems, the present invention provides a comprehensive treatment method for landfill leachate and kitchen waste water, which adopts the combined process of BBR-BDD-BBAF for treatment, and first removes most of the organic matter and total nitrogen in the waste water through the BBR biochemical treatment process. Pollutants such as total phosphorus have the characteristics of high degree of pollutant degradation and stable treatment effect; then, the remaining refractory organic matter in the wastewater is continued to be treated by electro-oxidation technology (BDD), and the refractory organic matter continues to be decomposed, while the organic nitrogen converted into nitrate nitrogen; after that, the BBAF unit consists of anaerobic tank (denitrification biological filter) and aerobic tank (nitrification biological aerated filter) to remove nitrate nitrogen and residual organic matter in the BDD effluent, respectively, and in The aerobic pool is added with biological fillers attached to Bacillus, and the produced water can reach the discharge standard limits in Table 2 and Table 3 in GB16889.

The comprehensive treatment method of the landfill leachate and kitchen waste water comprises the following steps:

S1: After the landfill leachate and kitchen waste water are homogeneously adjusted, they are input into the BBR treatment unit for biochemical treatment, and the organic matter in the waste water is degraded by Bacillus to obtain the primary treatment waste water;

S2: The primary treatment wastewater is input into the BDD treatment unit, and undergoes the first-level flocculation treatment, the first-level electrolysis treatment, the second-level electrolysis treatment and the second-level flocculation treatment in order to treat the refractory organic matter and organic nitrogen, and obtain the secondary treatment wastewater;

S3: The secondary treatment wastewater is input to the BBAF treatment unit, and undergoes anaerobic treatment, aerobic treatment, and biochemical treatment of Bacillus in sequence to treat nitrate nitrogen and residual organic matter in the secondary treatment wastewater to obtain produced water.

Optionally, in step S1, the landfill leachate and kitchen waste wastewater are first input into the adjustment tank for homogeneous adjustment, and then input into the BBR treatment unit for biochemical treatment. The BBR treatment unit includes the wastewater biochemical treatment tank and the wastewater biochemical treatment tank. Several circular biological turntable equipment, the biological turntable is used as a biological carrier, attaching and proliferating a large number of bacillus, the wastewater biochemical treatment pool is used to accommodate and treat landfill leachate and kitchen waste water; a part of the biological turntable is immersed in nano-garbage leachate and kitchen waste The rest of the waste water is exposed to the air, and the center of the biological turntable is provided with a rotating shaft. Under the rotation of the rotating shaft, the biological turntable is alternately in the waste water and the air. The BBR treatment unit of the present invention can adopt the patent No. 2021219913445, which is called a plug-in installation type three-dimensional biological turntable sewage treatment device.

The intensification of BBR bacillus and the low dissolved oxygen control in the biochemical aeration tank lead to partial accumulation of nitrite in the nitrification process of ammonia nitrogen in landfill leachate and kitchen waste wastewater, and part of the short-range nitrification and denitrification in the removal process of total nitrogen. process, reducing the carbon source demand in the denitrification process, coupled with the high-efficiency hydrolysis of refractory organic matter by the BBR biological turntable, the utilization rate of raw water carbon source is improved, and the efficient removal of TN under low BOD/TN conditions is realized ; The concentration of pollutants in landfill leachate and kitchen waste water is relatively high, and a lot of heat will be released during the treatment process, especially in the southern region in summer, the water temperature will rise above 40°C, usually the A/O-MBR process needs to be The treatment facilities are equipped with high-power cooling and cooling devices to effectively control the water temperature, which requires a large amount of electric energy. However, the BBR process used in the present invention has a wide range of adaptability to the temperature. When the water temperature is not higher than 43°C, the overall system is stable. It can run stably without setting up a cooling device or reducing the power of the cooling device.

Optionally, in step S2, the BDD treatment unit includes a first-level flocculation tank, a first-level electrolysis tank, a second-level electrolysis tank, a circulation tank and a second-level flocculation tank connected in sequence, and the wastewater biochemical treatment tank of the BBR treatment unit The outlet of the first-level flocculation tank is connected to the inlet of the first-level flocculation tank, and the outlet of the first-level flocculation tank is connected to the outer circulation inlet of the circulation tank. First-level electrolytic cell; the outlet of the first-level electrolytic cell is connected to the inlet of the second-level electrolytic cell, and the outlet of the second-level electrolytic cell is connected to the inner circulation inlet of the circulation pool. After the first-level electrolysis and second-level electrolysis, the waste water returns to the circulation pool; The outlet of the external circulation is connected to the inlet of the secondary flocculation tank, and the outlet of the secondary flocculation tank is connected to the BBAF processing unit.

Optionally, a water quality detector is provided in the circulation pool. When the wastewater index in the circulation pool is unqualified, the waste water will return to the first-stage electrolytic pool through the inner circulation outlet, and then go through two-stage electrolytic treatment, and then return to the circulation pool; When the wastewater index of the pool is qualified, it enters the secondary flocculation tank through the outlet of the external circulation for secondary flocculation treatment. The above method of cyclic electrolysis effectively guarantees the water quality of the two-stage electrolytic treatment. Even in the face of large fluctuations in the water quality of landfill leachate and kitchen waste wastewater, it can also cope with and ensure the water quality of the secondary treatment wastewater.

Optionally, a negative pressure air induction device is provided on the top of the circulation pool, and the negative pressure air induction device includes a negative pressure air induction fan and an air induction pipe for discharging the odor in the circulation pool; the air induction pipe and the external spray tower Connected, the spray tower absorbs the gas discharged from the draft duct through the spray agent.

Further optionally, the primary electrolytic cell is provided with graphene cathode and anode electrodes, and the secondary electrolysis cell is provided with boron-doped diamond anode and cathode electrodes. Compared with commonly used graphite electrodes or noble metal electrodes, graphene electrodes and boron-doped diamond electrodes have stronger oxidation ability, higher anode oxygen evolution potential, lower anode resistance, higher chemical stability and anti-pollution ability.

Optionally, the BDD processing unit also includes a flocculant dosing device and an oxygen scavenger dosing device, and the flocculant dosing device is respectively connected to the primary flocculation tank and the secondary flocculation tank through two parallel pipelines. A flocculant metering pump is installed on the two parallel pipelines, and pH sensors are respectively installed under the liquid surface of the primary flocculation tank and the secondary flocculation tank to monitor the pH value of the water in the two flocculation tanks. The device determines the amount of flocculant required for each flocculation tank according to the pH value, and adds it through the flocculant metering pump;

The oxygen scavenger dosing device is connected to the secondary flocculation tank through the oxygen scavenger metering pump. An ORP sensor is installed under the liquid level of the secondary flocculation tank to monitor the oxidation-reduction potential of the water in the secondary flocculation tank. The device judges the amount of oxygen scavenger to be added according to the value of the oxidation-reduction potential, and quantitatively adds the oxygen scavenger to the secondary flocculation tank through the oxygen scavenger metering pump to remove the chlorine gas generated by the front-end electrolysis process in the water to prevent secondary flocculation. The excess chlorine in the treated wastewater enters the BBAF treatment unit to kill the bacteria in the BBAF treatment unit.

Both the flocculant and the oxygen scavenger are generally used in the water treatment industry. Preferably, the oxygen scavenger includes a reducing agent and an auxiliary agent, the reducing agent is selected from two or more combinations of sodium sulfide, calcium polysulfide, and mercaptan, and the auxiliary agent is selected from soluble starch, A combination of two or more of sodium lignosulfonate and sodium divinyl sulfonate.

Optionally, in step S3, the BBAF treatment unit includes an anaerobic pond and an aerobic pond connected in sequence, the water body in the aerobic pond can be returned to the anaerobic pond, and the aerobic pond is provided with a biological filler attached to bacillus, which can The denitrification efficiency is greatly improved; the upper part of the aerobic tank is provided with a backwash water outlet, and the backwash water outlet is connected in parallel with a drain pipe and a return pipe. pool, and return part of the produced water to the regulating pool to dilute the raw water landfill leachate and kitchen waste water.

Optionally, both the anaerobic tank and the aerobic tank are equipped with biological fillers, and the biological fillers can be conventional BAF fillers, such as lightweight ceramsite, activated carbon and other inorganic fillers or polymer fillers. The biological filler in the anaerobic tank adheres to conventional anaerobic water treatment bacteria and anaerobic bacillus, and the biological filler in the aerobic tank adheres to conventional aerobic water treatment bacteria and bacillus. In the anaerobic tank, according to the actual wastewater treatment conditions, carbon sources are added, and carbon sources commonly used in this field can be selected.

The start-up of the anaerobic tank and the aerobic tank is a conventional technique in the field, that is, adopting inoculation culture, hanging film, and continuously injecting a certain amount of compound strains containing Bacillus and nutrient solution into the influent.

Steps S2 and S3 of the present invention are advanced treatment stages. In this stage, BDD electro-oxidation and BBAF process are creatively used in combination, and the strong oxidation ability of BDD electro-oxidation device (two-stage electrolytic cell) for organic matter is used to convert the primary treatment wastewater The refractory organic matter is decomposed into small molecular organic matter or CO ₂ , H ₂ O through the double action of electrode oxidation and advanced oxidation, and the residual organic nitrogen and ammonia nitrogen are oxidized into nitrate nitrogen. The secondary treatment wastewater enters the BBAF treatment unit, and through the biochemical action of anaerobic, aerobic and Bacillus, on the basis of the small molecule carbon source and the added carbon source of the secondary treatment wastewater, denitrification and denitrification are carried out, and the final effluent reaches Emission standards and discharge.

The BDD+BBAF advanced treatment process described in the present invention thoroughly decomposes and removes the pollutants in the primary treatment wastewater, realizes the harmlessness of the pollutants, and does not produce concentrated liquid, and realizes the full quantitative standard of wastewater Emission; the electro-oxidation process of the BDD treatment unit, in addition to the oxidation ability of the anode itself, will produce oxidative free radicals such as OH free radicals at the cathode, and the oxidation efficiency of the refractory organic matter is higher under the combined action; at the same time, the BDD treatment The unit mainly utilizes electric energy, does not increase the salt content in the wastewater, and overcomes the disadvantages of Fenton reagent and acid-base adjustment in the traditional Fenton and BAF combination process mentioned in the background technology. In the process of treating wastewater, the BDD treatment unit only needs to control the voltage and current parameters of the electrodes of the two electrolytic cells according to the actual pollution situation of the wastewater. The operation is flexible and convenient, and it is convenient for operation and maintenance management.

Optionally, the bottoms of the primary flocculation tank and the secondary flocculation tank are respectively provided with a sludge outlet, and both sludge outlets are connected to the sludge tank, and the bottoms of the anaerobic tank and the aerobic tank are respectively provided with One sludge outlet, and two sludge outlets are connected to the sludge tank; the sludge outlet of the sludge tank is connected to the filter press device, and the upper part of the sludge tank is provided with a supernatant outlet, which is connected to the regulating tank, and the filter press The sludge outlet of the device discharges the sludge after pressure filtration;

Step S2 also includes inputting the sludge generated from the first-level flocculation tank and the second-level flocculation tank into the sludge tank, and the sludge collected in the sludge tank is centrally input into the filter press device for filter press dehydration treatment to realize sludge reduction and treatment The final sludge is discharged and transported outside for treatment or reuse;

Step S3 also includes that the sludge generated from the anaerobic tank and the aerobic tank is input into the sludge tank, and the sludge collected in the sludge tank is collectively input into the filter press device for filter press dehydration treatment.

Both step S2 and step S3 include the following steps: the supernatant of the sludge tank is returned to the adjustment tank to dilute and adjust the raw water landfill leachate and kitchen waste water.

Optionally, the primary flocculation tank includes a central filtration zone and a flocculation zone around the filter zone, the filtration zone and the flocculation zone are separated by a partition, and there is a space between the bottom of the partition and the bottom of the primary flocculation tank to form a circle The water outlet connects the filter area and the flocculation area at the bottom of the primary flocculation tank, allowing the water in the flocculation area to enter the filter area;

The flocculation zone is evenly divided into several stirring zones, that is, several stirring zones are arranged around the circumferential direction of the filtration zone, and there is no separation device between adjacent stirring zones, that is, adjacent stirring zones are connected to each other; each stirring zone There is a stirrer in the center, and each stirring zone is equipped with a flocculant dosing port and a stirring zone water inlet;

A sand filter layer is provided at the bottom of the filter area, and a slant plate separation area is provided above the sand filter layer. The slant plate separation area includes several inclined, parallel to each other slant plates, and a first-stage flocculation unit is provided above the slant plate separation area. The exit of the pool.

Optionally, the water inlet of the stirring zone is arranged on the upper part of the stirring zone, and is arranged around the circumference of the primary flocculation tank relative to the water inlet of the stirring zone, and each water inlet of the stirring zone is connected in parallel to the wastewater biochemical treatment tank of the BBR treatment unit The outlet of the primary treatment wastewater is input into the corresponding stirring zone through several stirring zone water inlets.

Optionally, the flocculant dosing port is set at the upper part of the stirring zone, the pH sensor is set at the middle and upper part of the flocculation zone, and the flocculant adding ports of each stirring zone are connected in parallel and connected to the flocculant by a flocculant metering pump The dosing device, according to the monitoring data of the pH sensor, the flocculant metering pump controls the dosage of the flocculant, and then adds the flocculant to the corresponding stirring zone through several coagulant dosing ports to treat the wastewater once.

Optionally, the side wall of the bottom of the first-stage flocculation tank is inwardly inclined, and the bottom of the partition is outwardly inclined, that is, the bottom of the flocculation zone is tapered gradually, which is convenient Collect the sludge generated by flocculation reaction;

There is a sludge outlet at the bottom of each mixing zone to discharge the sludge from each mixing zone separately, or there is a sludge outlet at the bottom of the flocculation zone to uniformly discharge the sludge from each mixing zone, and the sludge outlet is connected to the sludge tank.

Optionally, the water outlet is provided with a filter screen, and the mesh aperture of the filter screen is smaller than the filter sand particle size of the sand filter layer, so as to prevent the filter sand from entering the flocculation area and being lost by the mud outlet; the bottom of the primary flocculation tank is provided with Sand outlet.

The wastewater from the primary treatment is treated in the flocculation area, passes through the filter screen from the water outlet, enters the bottom of the filter area, passes through the sand filter layer from bottom to top, and then rises to the inclined plate separation area to continue the separation of mud and water, and the sludge is slid by the inclined plate Down to the sand filter layer, the clear water is discharged from the outlet of the first-level flocculation tank to the circulation tank, and the outlet of the first-level flocculation tank runs through the partition, the flocculation area and the side wall of the first-level flocculation tank in turn; due to the sand filter layer The filter sand at the bottom receives waste water pollutants first, so it needs to be replaced first, and it is discharged from the sand discharge port, and it is washed and cleaned externally. Fresh filter sand or cleaned filter sand is added from the top of the filter area.

Optionally, the structure of the secondary flocculation tank is the same as that of the primary flocculation tank. The difference is that the water inlets of each stirring zone of the secondary flocculation tank are connected in parallel to the external circulation outlet of the circulation tank, and the qualified waste water in the circulation tank is composed of several The water inlet of each stirring zone is input into the corresponding stirring zone; the flocculant metering pump connected to the flocculant dosing port of the second flocculation tank is not the same as the flocculant metering pump connected to the first flocculation tank; the outlet of the second flocculation tank runs through in turn The partition plate of the secondary flocculation tank, the flocculation area and the side wall of the secondary flocculation tank are connected to the anaerobic tank.

The first-level flocculation tank and the second-level flocculation tank of the present invention integrate flocculation and filtration, and are connected through the water outlet to realize the flow direction of the water body in the flocculation area from top to bottom and the water body in the filtration area from bottom to top, making full use of The flocculation tank space improves the flocculation efficiency, optimizes the effluent water quality of the flocculation tank, and is beneficial to the subsequent treatment environment.

Description of drawings

Fig. 1 is the process flow chart of embodiment 1;

Fig. 2 is the equipment schematic diagram of embodiment 1;

Figure 3 is a schematic diagram of the connection of the electrolytic part of the BDD;

Fig. 4 is the schematic diagram of the three-dimensional structure of the primary flocculation tank of embodiment 3;

Fig. 5 is the top view of the primary flocculation tank;

Fig. 6 is a cross-sectional view of the primary flocculation tank.

In the accompanying drawings, 1-regulating tank, 2-BBR processing unit, 3-first-level flocculation tank, 4-first-level electrolytic tank, 5-secondary electrolytic tank, 6-circulation tank, 7-secondary flocculation tank, 8- Outer circulation inlet, 9-internal circulation outlet, 10-inner circulation inlet, 11-external circulation outlet, 12-negative pressure air induction device, 13-flocculant dosing device, 14-deoxidizer dosing device, 15-flocculation Agent metering pump, 16-deoxidizer metering pump, 17-anaerobic tank, 18-aerobic tank, 19-sludge tank, 20-press filter device, 21-filtration area, 22-flocculation area, 23-baffle , 24-Water outlet, 25-Stirring zone, 26-Sand filter layer, 27-Inclined plate separation zone, 28-Water inlet of stirring zone, 29-Sand discharge port, 30-Circulating pump.

detailed description

The landfill leachate and kitchen waste water treated in the following examples and comparative examples all come from a certain urban waste treatment plant and municipal sewage plant, and the treatment capacity is 50t/d. The water quality of the landfill leachate and kitchen waste water after homogeneous adjustment is as follows:

COD_Cr(mg/L) NH₃-N (mg/L) TN (mg/L) flooded 7354 1958 2472

Example 1

The comprehensive treatment method for landfill leachate and kitchen waste water described in this embodiment, as shown in Figures 1-3, includes the following steps:

(1) The landfill leachate and kitchen waste wastewater are first input into the adjustment tank 1, after homogeneous adjustment, they are input into the BBR treatment unit 2 for biochemical treatment, and the organic matter in the wastewater is degraded by Bacillus to obtain primary treated wastewater;

The BBR treatment unit 2 includes a wastewater biochemical treatment tank and several circular biological turntables in the wastewater biochemical treatment tank. The biological turntable is used as a biological carrier to attach and proliferate a large number of bacillus. The wastewater biochemical treatment tank is used to accommodate and treat landfill leachate and kitchen waste water; part of the biological turntable is immersed in the leachate and kitchen waste water, and the other part is exposed to the air. There is a rotating shaft in the center of the biological turntable. Under the rotation of the rotating shaft, the biological turntable is alternately in the waste water and the air;

The BBR treatment unit 2 of this embodiment can adopt the patent No. 2021219913445, which is a plug-in installation type three-dimensional biological turntable sewage treatment device. The surface area of a single biological turntable is 750m ² , the power is 2.2kW, and the amount of film hanging is 3.5~ 4.5t/set, a total of 4 sets are set up, and a total of 500kg of Qinghai Jieshen BBR compound Bacillus strains are inoculated; the hydraulic retention time of the wastewater biochemical treatment tank is 7 days, the gas-water ratio is 110-170, and the reflux ratio is 100%;

(2) The primary treatment wastewater is input into the BDD treatment unit, and then undergoes primary flocculation treatment, primary electrolysis treatment, secondary electrolysis treatment and secondary flocculation treatment to process refractory organic matter and organic nitrogen to obtain secondary treatment wastewater;

(3) The secondary treatment wastewater is input into the BBAF treatment unit, and undergoes anaerobic treatment, aerobic treatment, and biochemical treatment of Bacillus in sequence to treat nitrate nitrogen and residual organic matter in the secondary treatment wastewater to obtain produced water.

In step S2, the BDD processing unit includes a first-level flocculation tank 3, a first-level electrolytic tank 4, a second-level electrolytic tank 5, a circulation tank 6, and a second-level flocculation tank 7 connected in sequence, and the above five tanks are all ordinary The pool body, without any barrier structure in the pool, is a pool body with a single chamber.

The outlet of the wastewater biochemical treatment tank of the BBR treatment unit 2 is connected to the inlet of the primary flocculation tank 3, the outlet of the primary flocculation tank 3 is connected to the external circulation inlet 8 of the circulation pool 6, and the internal circulation outlet 9 of the circulation pool 6 passes through the circulation pump 30 is connected to the inlet of the primary electrolytic cell 4, and the waste water from the primary flocculation cell 3 is imported into the primary electrolytic cell 4; the outlet of the primary electrolytic cell 4 is connected to the import of the secondary electrolytic cell 5, and the outlet of the secondary electrolytic cell 5 is connected to The inner circulation inlet 10 of the circulation pool 6, the waste water returns to the circulation pool 6 after the first-level electrolysis and the second-level electrolysis; the outer circulation outlet 11 of the circulation pool 6 is connected to the entrance of the second-level flocculation tank 7, and the outlet of the second-level flocculation tank 7 is connected to The BBAF processing unit.

The circulation pool 6 is provided with a water quality detector, and when the wastewater index in the circulation pool 6 is unqualified, the waste water will return to the first-stage electrolytic pool 4 through the internal circulation outlet 9, undergo two-stage electrolytic treatment again, and then return to the circulation pool 6 ; When the wastewater index of the circulation pool 6 is qualified, it enters the secondary flocculation pool 7 through the external circulation outlet 11 for secondary flocculation treatment.

The top of described circulating pool 6 is provided with negative pressure induced draft device 12, and negative pressure induced draft device 12 comprises negative pressure induced draft fan and induced draft pipeline, is used to discharge the foul smell in circulating pool 6; The tower is connected, and the spray tower absorbs the gas discharged from the draft duct through the spray agent.

The primary electrolytic cell 4 is provided with graphene electrodes, and the secondary electrolytic cell 5 is provided with boron-doped diamond anode and cathode electrodes.

The BDD processing unit also includes a flocculant dosing device 13 and an oxygen scavenger dosing device 14, and the flocculant dosing device 13 is respectively connected to the primary flocculation tank 3 and the secondary flocculation tank 7 through two parallel pipelines. A flocculant metering pump 15 is respectively provided on the two parallel pipelines, and pH sensors are respectively provided under the liquid surface of the primary flocculation tank 3 and the secondary flocculation tank 7 for monitoring the pH value of the water in the two flocculation tanks. The flocculant dosing device 13 determines the amount of flocculant required for each flocculation tank according to the pH value, and adds it through the flocculant metering pump 15;

The oxygen scavenger dosing device 14 is connected to the secondary flocculation tank 7 through the oxygen scavenger metering pump 16, and an ORP sensor is arranged under the liquid level of the secondary flocculation tank 7 for monitoring the oxidation-reduction potential of the water body in the secondary flocculation tank 7, The oxygen scavenger dosing device 14 determines the amount of oxygen scavenger to be added according to the value of the oxidation-reduction potential, and quantitatively adds the oxygen scavenger to the secondary flocculation tank 7 through the oxygen scavenger metering pump 16 .

The flocculant is polyaluminum chloride. The oxygen scavenger is a combination of soluble starch, sodium lignosulfonate, sodium sulfide and dodecyl mercaptan.

The process conditions of step S2 are: the hydraulic retention time of the primary flocculation tank 3 is 1 h, the dosage of flocculant is 250 mg for 1 L of wastewater; the area of the positive and negative electrode plates of the primary electrolytic tank 4 is 8 m ² , and the current density is 400 A /m ² ; the area of the positive and negative electrode plates of the secondary electrolytic cell 5 is 0.5m ² , and the current density is 800A/m ² ; the hydraulic retention time of the secondary flocculation cell 7 is 1h, and the dosage of flocculant is 1L of wastewater 100mg, and the dosage of oxygen scavenger is 70mg for 1L of wastewater.

In step S3, the BBAF treatment unit comprises an anaerobic pond 17 and an aerobic pond 18 connected in sequence, the water body of the aerobic pond 18 can flow back to the anaerobic pond 17, and the aerobic pond 18 is provided with a biological filler attached to bacillus, The denitrification efficiency can be greatly improved; the upper part of the aerobic tank 18 is provided with a backwash water outlet, and the backwash water outlet is connected in parallel with a drain pipe and a return pipe, and the drain pipe discharges the produced water or enters the backwash water to flush the BBAF processing unit, and the return pipe Connect the adjustment tank 1 and the wastewater biochemical treatment tank, and return part of the produced water to the adjustment tank 1 or the wastewater biochemical treatment tank.

Both the anaerobic tank 17 and the aerobic tank 18 are equipped with biological fillers, and the biological fillers are selected from spherical ceramsite, and the biological fillers in the anaerobic tank are attached to conventional anaerobic water treatment bacteria and anaerobic bacillus. The biological filler in the tank adheres to conventional aerobic water treatment bacteria and bacillus. The carbon source glucose is added into the anaerobic pool 17 according to the actual wastewater treatment situation. When starting up, both the anaerobic pool 17 and the aerobic pool 18 adopt the method of inoculation culture, film formation, and continuous input of a certain amount of compound strains containing bacillus and nutrient solution into the influent.

The process conditions of step S3 are: the surface hydraulic load of the anaerobic pool 17 is 2.6m ³ /m ² ·h (excluding reflux liquid), the NOx load is 0.75kgNO ³ -N/m ³ ·d, the surface of the aerobic pool 18 The hydraulic load is 2.6m ³ /m ² h, the aerobic pool 18 is inoculated with compound aerobic bacteria and Qinghai Jieshen BBR compound Bacillus strains 200kg, and the anaerobic pool 17 is inoculated with Qinghai Jieshen BBAF compound anaerobic bacteria; The water backwashing intensity is 16m ³ /(m ² ·h), the glucose carbon source COD equivalent of the anaerobic tank 17 is 250000mg/L, and the dosing concentration is 80-150L/d.

The bottoms of the first-level flocculation tank 3 and the second-level flocculation tank 7 are respectively provided with a mud outlet, and both mud outlets are connected to the sludge tank 19, and the bottoms of the anaerobic tank 17 and the aerobic tank 18 are respectively provided with There is a sludge outlet, and two sludge outlets are connected to the sludge tank 19; the sludge outlet of the sludge tank 19 is connected to the filter press 20, and the upper part of the sludge tank 19 is provided with a supernatant water outlet, and is connected to the Regulating pool 1, the mud outlet of pressure filter device 20 discharges the sludge after pressure filtration.

Step S2 also includes inputting the sludge produced by the primary flocculation tank 3 and the secondary flocculation tank 7 into the sludge tank 19, and the sludge collected in the sludge tank 19 is collectively input into the filter press device 20 for press filter dehydration treatment to realize sludge dewatering. Sludge reduction, the treated sludge is discharged and transported outside for further treatment or reuse;

Step S3 also includes that the sludge generated in the anaerobic tank 17 and the aerobic tank 18 is input into the sludge tank 19, and the sludge collected in the sludge tank 19 is collectively input into the filter press device 20 for filter press dehydration treatment.

Both step S2 and step S3 include the following steps: the supernatant of the sludge tank 19 is returned to the regulating tank 1 to dilute and regulate the raw water landfill leachate and kitchen waste water.

Comparative example 1

The comprehensive treatment method for landfill leachate and kitchen waste wastewater described in this comparative example is the same as that in Example 1, except that in step (3), no bacillus biological filler is provided in the aerobic pool 18 .

Comparative example 2

The comprehensive treatment method of landfill leachate and kitchen waste wastewater described in this comparative example is the same as in Example 1, the difference is that in step (2), the common Fenton advanced oxidation device and flocculation tank connected in turn to the sewage treatment industry are used to replace all In the BDD processing unit described above, Fenton reagent composed of Fe(II) ions and H ₂ O ₂ is added to the Fenton advanced oxidation device, and the pH value is adjusted to 1-2 with hydrochloric acid to perform advanced oxidation. After the reaction is completed, hydrogen oxidation is also added. Sodium adjusts the pH to neutral, and the upper water body is input into the flocculation tank, and the flocculant polyaluminum chloride is put in for flocculation to obtain secondary treatment wastewater.

Comparative example 3

The comprehensive treatment method of landfill leachate and kitchen waste water described in this comparative example is the same as in Example 1, the difference is that in step (2), no primary flocculation treatment is performed, no circulation pool 6 is provided, and primary electrolytic cell 4 , secondary electrolytic cell 5, and secondary flocculation cell 7 are connected successively, and the outlet of secondary electrolytic cell 5 is connected in parallel with primary electrolytic cell 4 and secondary flocculation cell 7 through pipelines, and the primary treatment waste water is directly input into primary electrolytic cell 4, and then First-level electrolysis treatment, second-level electrolysis treatment; when the water quality of the water body after the second-level electrolysis treatment is unqualified, return to the first-level electrolytic cell 4 to continue electrolysis; after the water quality of the second-level electrolysis treatment is qualified, the water body enters the second-level flocculation tank 7.

Both the flocculant dosing device 13 and the oxygen scavenger dosing device 14 are connected to the secondary flocculation tank 7 to add chemicals.

Example 2

The comprehensive treatment method of landfill leachate and kitchen waste water described in this embodiment is the same as that of Embodiment 1, the difference is that, as shown in Figures 4-6, the primary flocculation tank 3 includes a filter area 21 in the middle and a filter area The flocculation zone 22 around the zone 21, the filtration zone 21 and the flocculation zone 22 are separated by a partition 23, and the bottom of the partition 23 has a space with the bottom of the primary flocculation tank 3, forming a circle of water outlet 24, so that the filtration zone 21 and the flocculation The zone 22 is connected at the bottom of the primary flocculation tank 3, allowing the water body in the flocculation zone 22 to enter the filter zone 21;

The flocculation zone 22 is evenly divided into four stirring zones 25, that is, several stirring zones 25 are arranged around the circumferential direction of the filtration zone 21, and there is no separating device between adjacent stirring zones 25, that is, the adjacent stirring zones 25 are separated from each other. connected; the center of each stirring zone 25 is provided with a stirrer, and each stirring zone 25 is provided with a flocculant feeding port and a stirring zone water inlet 28;

The bottom of the filter area 21 is provided with a sand filter layer 26, and the top of the sand filter layer 26 is provided with an inclined plate separation area 27. The inclined plate separation area 27 includes several inclined, parallel inclined plates, and the inclined plate separation area 27 The outlet of the primary flocculation tank 3 is provided above.

The stirring zone water inlet 28 is arranged on the top of the stirring zone 25, and is arranged around the circumferential direction of the primary flocculation tank 3 relative to the stirring zone water inlet 28. After each stirring zone water inlet 28 is connected in parallel, it is connected to the biochemical waste water of the BBR treatment unit 2. The outlet of the treatment pool, the primary treatment wastewater is input into the corresponding stirring zone 25 through several stirring zone water inlets 28 .

The flocculant dosing port is set on the upper part of the stirring zone 25, and the pH sensor is set on the middle and upper part of the flocculation zone 22. After the flocculant feeding ports of each stirring zone 25 are connected in parallel, the flocculant metering pump 15 is connected to the flocculant The dosing device 13, according to the monitoring data of the pH sensor, the flocculant metering pump 15 controls the dosage of the flocculant, and then adds the flocculant to the corresponding stirring zone 25 through several coagulant dosing ports to treat the waste water once .

The side wall of the bottom of the first-stage flocculation tank 3 is inwardly inclined, and the bottom of the partition 23 is outwardly inclined, that is, the bottom of the flocculation zone 22 is tapered gradually, which is convenient for collecting Sludge produced by flocculation reaction; a sludge outlet is provided at the bottom of the flocculation zone 22 to uniformly discharge the sludge from each mixing zone 25 , and the sludge outlet is connected to the sludge pool 19 .

The water outlet 24 is provided with a filter screen, and the mesh aperture of the filter screen is less than the filter sand particle size of the sand filter layer 26, preventing the filter sand from entering the flocculation zone 22 and being lost by the mud outlet; the bottom of the primary flocculation tank 3 is provided with Sand outlet 29.

The primary treated wastewater is treated in the flocculation area 22, passes through the filter screen from the water outlet 24, enters the bottom of the filter area 21, passes through the filter of the sand filter layer 26 from bottom to top, and then rises to the inclined plate separation area 27 to continue the separation of mud and water. The mud slides down to the sand filter layer 26 from the inclined plate, and the clear water is discharged from the outlet of the primary flocculation tank 3 to the circulation tank 6, and the outlet of the primary flocculation tank 3 runs through the separator 23, the flocculation zone 22 and the primary The side wall of the flocculation tank 3; since the filter sand at the bottom of the sand filter layer 26 receives waste water pollutants first, it needs to be replaced at first, and is discharged from the sand discharge port 29, and is cleaned externally. Fresh filter sand or cleaned The filter sand is added from the top of the filter zone 21.

The structure of the secondary flocculation tank 7 is the same as that of the first-level flocculation tank. The difference is that each stirring zone water inlet of the secondary flocculation tank 7 is connected in parallel to the external circulation outlet 11 of the circulation tank, and the qualified waste water in the circulation tank 6 is produced by The water inlets of several stirring zones are input into the corresponding stirring zones; the flocculant metering pump connected to the flocculant dosing port of the secondary flocculation tank 7 is not the same as the flocculant metering pump connected to the primary flocculation tank; The outlet runs through the partition of the secondary flocculation tank, the flocculation zone and the side wall of the secondary flocculation tank in sequence, and then connects to the anaerobic tank 17 .

The water quality comparison of the BBAF treatment unit of table 1 embodiment and comparative example

It can be seen from the above table that the comprehensive treatment method of landfill leachate and kitchen waste water provided by the present invention uses the combined treatment method of BBR+BDD+BBAF to treat landfill leachate and kitchen waste water with a relatively high content of organic pollutants. Wastewater with high ammonia nitrogen content has a good treatment effect.

Claims (10)

1. A comprehensive treatment method of landfill leachate and kitchen waste water is characterized by comprising the following steps:

s1: homogenizing and adjusting the landfill leachate and the kitchen waste water, inputting the garbage leachate and the kitchen waste water into a BBR (barium Broth-Barre) treatment unit for biochemical treatment, and degrading organic matters in the waste water by using bacillus to obtain primary treatment waste water;

s2: inputting the primary treatment wastewater into a BDD treatment unit, and sequentially performing primary flocculation treatment, primary electrolysis treatment, secondary electrolysis treatment and secondary flocculation treatment to treat refractory organic matters and organic nitrogen to obtain secondary treatment wastewater;

s3: and inputting the secondary treatment wastewater into a BBAF treatment unit, and treating nitrate nitrogen and residual organic matters in the secondary treatment wastewater to obtain produced water through anaerobic treatment, aerobic treatment and biochemical treatment of bacillus in sequence.

2. The method of claim 1, wherein in step S1, the landfill leachate and the kitchen waste water are first introduced into a conditioning tank for homogeneous conditioning and then introduced into a BBR treatment unit for biochemical treatment, wherein the BBR treatment unit comprises a waste water biochemical treatment tank and a plurality of circular biological rotating disc devices in the waste water biochemical treatment tank, the biological rotating discs are used as biological carriers for attaching and proliferating bacillus, and the waste water biochemical treatment tank is used for accommodating and treating the landfill leachate and the kitchen waste water.

3. The comprehensive treatment method of landfill leachate and kitchen waste water as claimed in claim 2, wherein in step S2, the BDD treatment unit comprises a primary flocculation tank, a primary electrolytic tank, a secondary electrolytic tank, a circulation tank and a secondary flocculation tank which are connected in sequence, wherein the primary electrolytic tank is provided with a graphene positive and negative electrode, and the secondary electrolytic tank is provided with a boron-doped diamond positive and negative electrode;

an outlet of a wastewater biochemical treatment tank of the BBR treatment unit is connected with an inlet of a first-stage flocculation tank, an outlet of the first-stage flocculation tank is connected with an external circulation inlet of a circulation tank, an internal circulation outlet of the circulation tank is connected with an inlet of a first-stage electrolytic tank through a circulation pump, and wastewater from the first-stage flocculation tank is led into the first-stage electrolytic tank;

the outlet of the first-stage electrolytic cell is connected with the inlet of the second-stage electrolytic cell, the outlet of the second-stage electrolytic cell is connected with the internal circulation inlet of the circulation pool, and the wastewater returns to the circulation pool after first-stage electrolysis and second-stage electrolysis; the outer circulation outlet of the circulation tank is connected with the inlet of the secondary flocculation tank, and the outlet of the secondary flocculation tank is connected with the BBAF treatment unit.

4. The method for comprehensively treating landfill leachate and kitchen waste water as claimed in claim 3, wherein a water quality detector is disposed in the circulation tank, and when the wastewater index in the circulation tank is not qualified, the wastewater is returned to the first-stage electrolytic tank through the internal circulation outlet, is subjected to two-stage electrolytic treatment again, and is then returned to the circulation tank;

when the wastewater index of the circulating tank is qualified, the wastewater enters a secondary flocculation tank through an external circulation outlet to be subjected to secondary flocculation treatment.

5. The comprehensive treatment method of landfill leachate and kitchen waste water according to claim 4, wherein the BDD processing unit further comprises a flocculant adding device and a deoxidant adding device, the flocculant adding device is respectively connected with the primary flocculation tank and the secondary flocculation tank through two parallel pipelines, a flocculant metering pump is respectively arranged on each of the two parallel pipelines, pH sensors are respectively arranged under the liquid level of each of the primary flocculation tank and the secondary flocculation tank and used for monitoring the pH value of water in the two flocculation tanks, and the flocculant adding device judges the flocculant dosage required by each flocculation tank according to the pH value and adds the flocculant dosage through the flocculant metering pump;

the oxygen scavenger adding device is connected with the secondary flocculation tank through an oxygen scavenger metering pump, an ORP sensor is arranged below the liquid level of the secondary flocculation tank and used for monitoring the oxidation-reduction potential of the water body of the secondary flocculation tank, the oxygen scavenger adding device judges the amount of oxygen scavenger to be added according to the numerical value of the oxidation-reduction potential, and the oxygen scavenger is quantitatively added into the secondary flocculation tank through the oxygen scavenger metering pump.

6. The method for comprehensively treating landfill leachate and kitchen waste water as claimed in claim 1, wherein in step S3, the BBAF treatment unit comprises an anaerobic tank and an aerobic tank which are connected in sequence, the water in the aerobic tank can flow back to the anaerobic tank, and the aerobic tank is provided with a biological filler attached with bacillus;

the upper portion of good oxygen pond is equipped with the back flush water export, and the back flush water export is parallelly connected drain pipe and back flow, and the drain pipe is discharged and is produced water or lets in the back flush water and wash BBAF processing unit, and the back flow connection equalizing basin is with some product water backward flow to the equalizing basin, dilutes raw water landfill leachate and kitchen waste water.

7. The method of claim 5, wherein the primary flocculation tank comprises a middle filtration zone and a flocculation zone around the filtration zone, the filtration zone and the flocculation zone are separated by a partition, and the bottom of the partition and the bottom of the primary flocculation tank have a space to form a circle of water passing openings, so that the filtration zone and the flocculation zone are communicated at the bottom of the primary flocculation tank, and water in the flocculation zone is allowed to enter the filtration zone;

the flocculation area is uniformly divided into a plurality of stirring areas, the plurality of stirring areas are distributed in the circumferential direction around the filtering area, and adjacent stirring areas are communicated with each other without a separation device; a stirrer is arranged in the center of each stirring area, and each stirring area is provided with a flocculating agent adding port and a stirring area water inlet;

the bottom of filtering area is equipped with the sand filtration layer, and the top of sand filtration layer is equipped with the swash plate disengagement zone, and the swash plate disengagement zone includes a plurality of inclined, the swash plate that is parallel to each other, and the top of swash plate disengagement zone is equipped with the export of one-level flocculation basin.

8. The method of claim 7, wherein the water inlets of the mixing zones are disposed at the upper portion of the mixing zones, each mixing zone water inlet is connected in parallel and then connected to the outlet of the wastewater biochemical treatment tank of the BBR treatment unit, and the primary treatment wastewater is inputted into the corresponding mixing zones through the water inlets of the mixing zones;

the flocculating agent feeding port is arranged on the upper portion of the stirring area, the pH sensor is arranged on the middle upper portion of the flocculation area, the flocculating agent feeding ports of all the stirring areas are connected in parallel and then connected with a flocculating agent feeding device through flocculating agent metering pumps, the flocculating agent metering pumps are used for controlling the feeding amount of the flocculating agent according to the monitoring data of the pH sensor, and then the flocculating agent is fed into the corresponding stirring area through the plurality of flocculating agent feeding ports to treat primary treatment wastewater.

9. The comprehensive treatment method of landfill leachate and kitchen waste water as claimed in claim 8, wherein the sidewall of the bottom of the primary flocculation tank is an inwardly inclined cone, the bottom of the partition is an outwardly inclined cone, and the bottom of the flocculation zone is a gradually narrowing cone, so as to facilitate collection of sludge generated by flocculation reaction;

every stirring district bottom is equipped with a mud outlet, discharges the mud in each stirring district respectively, perhaps flocculation district bottom is equipped with a mud outlet, the mud in each stirring district of unified discharge, mud outlet connection sludge impoundment.

10. The method of claim 9, wherein the water outlet is provided with a filter screen, the aperture of the filter screen is smaller than the sand filtering particle size of the sand filtering layer, so as to prevent the sand filtering from entering the flocculation area and flowing out from the sludge outlet; the bottom of the primary flocculation tank is provided with a sand discharge port.

Images