CN108178454B

CN108178454B - Non-membrane treatment method for kitchen waste wastewater

Info

Publication number: CN108178454B
Application number: CN201810059407.XA
Authority: CN
Inventors: 蔚建军; 曾祖刚; 况前; 黄安寿; 陈严华
Original assignee: Chongqing Environment & Sanitation Group Co ltd
Current assignee: Chongqing Yikang Environmental Protection Engineering Co.,Ltd.
Priority date: 2018-01-22
Filing date: 2018-01-22
Publication date: 2021-01-15
Anticipated expiration: 2038-01-22
Also published as: CN108178454A

Abstract

The invention discloses a kitchen waste wastewater non-membrane treatment method, which comprises the following steps: A. firstly, a processing system with the following structure is obtained: comprises a pretreatment system and a biochemical treatment system; the pretreatment system comprises a demulsification and coagulation device; the biochemical treatment system comprises a SHARON device, a hydrolysis acidification device, an A/O device and an ABFT device which are sequentially connected; the water inlet of the SHARON device is connected to the water outlet of the demulsification and coagulation device; B. the kitchen waste wastewater flows into a demulsification and coagulation device to remove suspended matters, animal and vegetable oil and dissolved oxygen in the wastewater; then enters a SHARON device for nitrogen removal, and then flows into a hydrolysis acidification device to decompose macromolecular organic matters in the wastewater into micromolecular organic matters; then the mixture enters an A/O device for nitration/denitrification reaction, finally enters an ABFT device for biochemical denitrification and then is precipitated, and the supernatant flows out. The invention has the advantages of no jet aeration and biomembrane, simple process, good treatment effect, low operation cost and the like.

Description

Non-membrane treatment method for kitchen waste wastewater

Technical Field

The invention relates to the technical field of kitchen waste treatment, in particular to a kitchen waste wastewater non-membrane treatment method.

Background

The kitchen waste wastewater is mainly derived from water contained in the kitchen waste and water generated in the fermentation process of the kitchen waste, the components of the kitchen waste wastewater are complex, the organic matter content is high, and the kitchen waste wastewater mainly contains dietary fiber, starch, fat, animal and vegetable oil, various seasonings, a detergent, protein and the like. Because the fatty acid decomposed by the kitchen waste under the action of high-temperature hydrolysis is not further degraded, the COD mass concentration of the generated wastewater is increased, the solid matters of the kitchen waste contain abundant proteins, and the proteins are aminated in the digestion process, so that the kitchen waste wastewater has high-level ammonia nitrogen and total nitrogen concentration, the carbon-nitrogen ratio is low, the anaerobic digestion is influenced, and the subsequent biochemical treatment of the wastewater is also influenced. Due to the inhibition effect of high ammonia nitrogen, biochemical treatment has great difficulty.

At present, the kitchen waste and wastewater are treated by an A/O + ultrafiltration treatment process, the process has high sludge concentration, short retention time and good stability, but the operation cost is very high due to the adoption of jet aeration and ultrafiltration effluent.

Disclosure of Invention

Aiming at the defects of the prior art, the technical problems to be solved by the invention are as follows: how to provide a kitchen waste water non-membrane method for treating without jet aeration and biomembrane, which has simple process and better treatment effect and is beneficial to reducing the operation cost.

In order to solve the technical problems, the invention adopts the following technical scheme:

a kitchen waste wastewater non-membrane treatment method is characterized by comprising the following steps:

A. firstly, a processing system with the following structure is obtained: comprises a pretreatment system for removing suspended matters, animal and vegetable oil and partial COD in the wastewater and a biochemical treatment system for performing denitrification treatment on the wastewater; the pretreatment system comprises a demulsification and coagulation device; the biochemical treatment system comprises a SHARON device for short-range denitrification, a hydrolytic acidification device for hydrolyzing and acidifying insoluble organic matters into soluble monomer or dimer compounds, an A/O device for denitrifying biological denitrification and an ABFT device for biochemical denitrification, which are sequentially connected; the water inlet of the SHARON device is connected to the water outlet of the demulsification and coagulation device;

B. the kitchen waste wastewater flows into a demulsification and coagulation device to remove suspended matters, animal and vegetable oil and dissolved oxygen in the wastewater; then enters a SHARON device for nitrogen removal, and then flows into a hydrolysis acidification device to decompose macromolecular organic matters in the wastewater into micromolecular organic matters; then the mixture enters an A/O device for nitration/denitrification reaction, finally enters an ABFT device for biochemical denitrification and then is precipitated, and the supernatant flows out.

Furthermore, the pretreatment system also comprises an oil separation sedimentation tank arranged at the front end of the demulsification and coagulation device, and a grid for filtering large-particle solid pollutants is arranged in the oil separation sedimentation tank.

Further, the demulsification and coagulation device comprises an air flotation tank for treating wastewater, a demulsifier tank for storing demulsifier, a coagulant tank for storing coagulant and a coagulant aid tank for storing coagulant aid; the system comprises a demulsifier tank, a coagulant tank and a coagulant aid tank, wherein the demulsifier tank, the coagulant tank and the coagulant aid tank are respectively connected to an air floatation tank through dosing pumps, an air stirring device for stirring is arranged in the air floatation tank, and the air stirring device is connected to an air source through a pipeline provided with a valve.

Further, the SHARON device comprises a collecting tank for collecting waste water, a SHARON tank for carrying out nitrification/denitrification and nitrogen removal and a post-storage tank for temporarily storing the nitrogen-removed waste water; a SHARON water inlet pump for pumping water is connected between the collecting tank and the SHARON tank; an overflow pipe convenient for supernatant to flow out is connected between the upper part of the SHARON tank and the rear storage tank, and an electromagnetic valve for controlling the on-off of the overflow pipe is arranged on the overflow pipe.

Furthermore, the A/O device comprises a denitrification tank, a nitrification tank and a secondary sedimentation tank, wherein a water outlet of the denitrification tank is connected to a water inlet of the nitrification tank, the nitrification tank is provided with a first backflow port connected to the denitrification tank, a water outlet of the nitrification tank is connected to the secondary sedimentation tank, the bottom of the secondary sedimentation tank is provided with a second backflow port used for backflow of sludge, and the second backflow port is connected to the denitrification tank.

Further, the ABFT device is including the ABFT pond that is used for carrying out biochemical denitrogenation for carry out mud-water separation's the final sedimentation pond and be used for the clear water pond of the supernatant of the final sedimentation pond of keeping in, the bottom in final sedimentation pond has the third backward flow mouth that is used for the mud backward flow, the third backward flow mouth connect to the ABFT pond, the upper end in final sedimentation pond has the liquid outlet that is used for the supernatant overflow, the liquid outlet is connected to the clear water pond.

Furthermore, the ABFT pool is provided with two anoxic zones and two aerobic zones which are sequentially arranged at intervals, net-shaped wide-hole fillers are arranged in the anoxic zones and the aerobic zones, and a large number of biological membranes and activated sludge zoogloea are attached to the fillers; and a third aeration device is also arranged in the aerobic zone.

In conclusion, the invention has the advantages of no jet aeration and biomembrane, simple process, good treatment effect, low operation cost and the like.

Drawings

Fig. 1 is a schematic structural diagram of a kitchen waste and wastewater non-membrane treatment system.

FIG. 2 is a schematic diagram of the pretreatment system of FIG. 1.

Detailed Description

The present invention will be described in further detail with reference to examples.

In the specific implementation: as shown in fig. 1 and fig. 2, a kitchen waste and wastewater non-membrane treatment system comprises a pretreatment system 1 for removing suspended matters, animal and vegetable oil and partial COD in wastewater, and a biochemical treatment system 2 for performing denitrification treatment on wastewater; the pretreatment system 1 comprises a demulsification and coagulation device 11; the biochemical treatment system 2 comprises a SHARON device 21 for short-range denitrification, a hydrolytic acidification device 22 for hydrolyzing and acidifying insoluble organic matters into soluble monomer or dimer compounds, an A/O device 23 for denitrification biological denitrification and an ABFT device 24 for biochemical denitrification, which are sequentially connected; the water inlet of the SHARON device 21 is connected to the water outlet of the demulsification and coagulation device 11.

Because the kitchen waste wastewater contains a large amount of (light oil) vegetable oil, animal oil (beef tallow, lard) and suspended solids, after the wastewater enters the demulsification coagulation device, the emulsified oil and the dispersed oil in the wastewater are destabilized and demulsified under the action of the demulsifier, oil-water separation is realized, then colloid particles in the wastewater and electrical neutralization destabilization and coagulation of hydrophilic pollutants are realized through the action of the coagulant and the coagulant aid, visible alum floc is formed through flocculation of hydrophobic organic matters and micro suspended solids, and then mud-water separation is realized through gravity settling or dissolved gas floating, so as to remove COD, BOD, SS, chroma, heavy metal elements and the like in the water. Pretreated wastewater flows into SHARONFollowing installation, nitrosobacteria in the SHARON device convert ammonia in the water to NO₂And N, and then directly carrying out denitrification to realize short-cut nitrification and denitrification so as to realize rapid nitrogen removal. The wastewater after nitrogen removal enters a hydrolysis acidification device, and hydrolysis acidification reaction is carried out under an anoxic environment to decompose part of macromolecular organic matters which are difficult to degrade into micromolecular organic matters which are easy to degrade, so that a carbon source is provided for a subsequent biological denitrification process, the adding amount of the carbon source is reduced, and the cost is reduced. And the effluent of the hydrolysis acidification device flows to the A/O device for nitration/denitrification reaction and then flows to the ABFT device, and the effluent is subjected to biochemical denitrification in the ABFT device and finally reaches the standard for discharge. The system can reach the wastewater discharge standard without adopting jet aeration and a biological membrane, and has lower operation cost.

In implementation, the pretreatment system 1 further comprises an oil separation sedimentation tank 12 arranged at the front end of the emulsion breaking and coagulation device 11, and a grid 121 for filtering large-particle solid pollutants is arranged in the oil separation sedimentation tank 12.

By adopting the structure, after the kitchen wastewater flows into the oil separation sedimentation tank, the kitchen wastewater passes through the grating, so that solid pollutants with particle sizes larger than the aperture of the grating are separated, a large amount of emulsified oil and dispersed oil are contained, the workload of a subsequent demulsification and coagulation device can be reduced, the consumption of a demulsifier, a coagulant and a coagulant aid is reduced, and the cost is reduced.

When the device is implemented, the grids are arranged in 121 times, and the aperture of the three grids is gradually reduced along the water inlet direction.

Utilize the grid that three apertures reduce gradually, can filter great, medium and less solid-state pollutant in proper order, avoid sewage to block the grid, be favorable to passing through oil separating sedimentation tank fast of waste water, improve the efficiency of handling.

In implementation, a plurality of guide plates 122 arranged in parallel at intervals are arranged in the oil separation sedimentation tank 12, one end of each guide plate 122 is fixed on the inner wall of the oil separation sedimentation tank 12, the other end of each guide plate is separated from the inner wall of the oil separation sedimentation tank 12 to form a flow passage, and the flow passages on two adjacent guide plates are respectively positioned on two sides of the length direction of each guide plate, so that an S-shaped flow passage is formed in the oil separation sedimentation tank 12.

By adopting the structure, a longer flow channel can be formed in the oil separation sedimentation tank with limited length, so that small-particle solid pollutants in the wastewater can be conveniently precipitated to the bottom of the tank within enough time, the workload of the grid is reduced, the frequency of cleaning and replacing the grid is reduced, and the service life of the grid is prolonged.

In implementation, the oil separation sedimentation tank 12 is also internally provided with an oil separation baffle 123 which is transversely arranged, the upper end of the oil separation baffle 123 is higher than the liquid level, the lower end of the oil separation baffle 123 is positioned below the liquid level, and an overflow gap is formed between the oil separation baffle 123 and the tank bottom; the oil-separation baffle 123 is located in front of the grill 121.

Therefore, the oil separation baffle can be used for blocking the floating objects on the water surface, the workload of the follow-up grating is reduced, the frequency of cleaning and replacing the grating is reduced, and the service life of the grating is prolonged.

In practice, the demulsification and coagulation device 11 comprises an air flotation tank 111 for treating wastewater, a demulsifier tank 112 for storing demulsifier, a coagulant tank 113 for storing coagulant and a coagulant aid tank 114 for storing coagulant aid; the demulsifier tank 112, the coagulant tank 113 and the coagulant aid tank 114 are respectively connected to the floatation tank 111 through dosing pumps, an air stirring device for stirring is arranged in the floatation tank 111, and the air stirring device is connected to an air source through a pipeline provided with a valve.

By adopting the structure, a proper amount of demulsifier, coagulant and coagulant aid can be respectively added into the air flotation tank by using the dosing pump, and simultaneously, the air stirring device is used for stirring, so that the medicament and the sewage are quickly mixed and react to form floccules.

In practice, the SHARON device 21 comprises a collecting tank 211 for collecting wastewater, a SHARON tank 212 for nitrification/denitrification and nitrogen removal, and a post-storage tank 213 for temporarily storing nitrogen-removed wastewater; a SHARON water inlet pump for pumping water is connected between the collection tank 211 and the SHARON tank 212; an overflow pipe convenient for supernatant to flow out is connected between the upper part of the SHARON pool 212 and the rear storage pool 213, and an electromagnetic valve for controlling the on-off of the overflow pipe is arranged on the overflow pipe.

By adopting the structure, the waste water is collected into a collecting tank after animal and vegetable oil and suspended matters carried in the waste water are removed by demulsification and air flotation, and then the waste water is pumped into a SHARON tank through a SHARON water inlet pump according to a SHARON operation program. In a SHARON pool, nitrosobacteria convert ammonia into NO under certain conditions of pH, temperature and dissolved oxygen₂And N, and then directly carrying out denitrification to realize short-cut nitrification and denitrification so as to achieve the aim of quickly removing nitrogen. In a SHARON tank, organic matters and ammonia nitrogen in the wastewater are degraded and removed by microorganisms (divided into two stages of nitrification and denitrification), and supernatant after precipitation is controlled by an electromagnetic valve in time and automatically flows into a rear storage tank.

In practice, a temperature sensor and a heating device are also arranged in the SHARON pool 212.

Under the conditions of high wastewater temperature and low dissolved oxygen, the nitrites with low growth rate are flushed away by utilizing different growth speeds of the nitrites and the nitrifying bacteria and controlling the hydraulic retention time, so that a large amount of nitrites are accumulated, and the short-cut nitrification can be successfully operated. In the above-mentioned structure, can be through the waste water temperature in temperature sensor real-time supervision pond to can utilize heating device to heat waste water, guarantee that waste water keeps in the best temperature range of SHARON technology, improve the efficiency of nitrifying/denitrification denitrogenation.

During implementation, the heating device is a steam heating pipe arranged in the SHARON pool 212, and the steam heating pipe is connected to a steam pipeline of the kitchen waste fermentation workshop through an electromagnetic valve.

As the kitchen waste wastewater mainly comes from water contained in the kitchen waste and water generated in the fermentation process of the waste, in the waste fermentation stage, water vapor is generated by a methane combustion boiler generated by fermentation and then is conveyed to a fermentation system for heating and heat preservation, so that the fermentation efficiency is improved. In the structure, the steam heating pipe is adopted, so that the steam generated in the previous process can be fully utilized, the energy recovery rate in the garbage treatment process is improved, and the cost input of the garbage treatment is reduced.

In implementation, the SHARON pool 212 is also provided with an insulating layer.

Therefore, the waste water heat in the SHARON pool can be prevented from being dissipated too fast, and the energy consumed by heating is reduced, thereby being beneficial to reducing the cost.

In practice, the SHARON pond 212 is further provided with a first aeration device for intermittent aeration.

Therefore, the wastewater in the SHARON pool can be always in a lower dissolved oxygen content through intermittent aeration, which is beneficial to the operation of short-cut nitrification.

In practice, the a/O device 23 includes a denitrification tank 231, a nitrification tank 232 and a secondary sedimentation tank 233, a water outlet of the denitrification tank 231 is connected to a water inlet of the nitrification tank 232, the nitrification tank 232 has a first return port connected to the denitrification tank 231, a water outlet of the nitrification tank 232 is connected to the secondary sedimentation tank 233, a bottom of the secondary sedimentation tank 233 has a second return port for returning sludge, and the second return port is connected to the denitrification tank 231.

The denitrification tank is in an anoxic state, the effluent automatically flows to the nitrification tank, and a large amount of microorganisms (activated sludge) in the nitrification tank are in full contact with substrates (degradable organic matters in wastewater and the like) in the nitrification tank to generate oxidation of carbon-containing organic matters, ammoniation of nitrogen-containing organic matters and nitrification of ammonia nitrogen. The mixed liquid in the nitrification tank flows back to the denitrification tank, and NO in the mixed liquid flows back₃And the-N utilizes the carbon-containing organic matters in the raw wastewater as carbon source substances to carry out denitrification reaction in a denitrification tank under the action of denitrifying bacteria. The secondary sedimentation tank carries out mud-water separation on effluent of the nitrification tank, sludge at the bottom returns to the denitrification tank, the sludge concentration of the whole A/O biological reaction tank is increased, and the nitrification and denitrification reaction efficiency is improved.

When in use, a submersible mixer is arranged in the denitrification tank 231.

Therefore, the stirrer can be used for fully mixing the inflowing wastewater and the backflow mixed liquid, so that denitrifying bacteria can conveniently carry out denitrification reaction, and the treatment efficiency is favorably improved.

In implementation, a second aeration device is arranged in the nitrification tank 232.

Therefore, the oxygen content in the nitrification tank can be increased, so that the microorganisms can be fully contacted with the degradable organic matters in the wastewater, and the oxidation of carbon-containing organic matters, the ammoniation of nitrogen-containing organic matters and the nitrification of ammonia nitrogen can be carried out. Improving the efficiency of the nitration reaction.

In practice, the ABFT device 24 includes an ABFT tank 241 for performing biochemical denitrification, a final sedimentation tank 242 for performing sludge-water separation, and a clean water tank 243 for temporarily storing supernatant in the final sedimentation tank, the bottom of the final sedimentation tank 242 has a third return port for returning sludge, the third return port is connected to the ABFT tank 241, the upper end of the final sedimentation tank 242 has a liquid outlet for overflowing supernatant, and the liquid outlet is connected to the clean water tank 243.

By adopting the structure, the final sedimentation tank carries out mud-water separation on the effluent of the ABFT tank, the sludge at the bottom returns to the front end of the ABFT tank, the sludge concentration of the ABFT tank is increased, and the nitrification and denitrification reaction efficiency is improved; and the supernatant of the final sedimentation tank automatically flows into the clear water tank and can be discharged after reaching the standard.

In implementation, the ABFT tank 241 is provided with two anoxic zones and two aerobic zones which are sequentially arranged at intervals, wherein net-shaped wide-hole fillers are arranged in the anoxic zones and the aerobic zones, and a large number of biological membranes and activated sludge zoogloea are attached to the fillers; and a third aeration device is also arranged in the aerobic zone.

By adopting the structure, a large amount of biomembranes and activated sludge zoogloea attached on the filler are in a suspension state in water, aeration is carried out at the bottom of the reactor to provide filler fluid power and react to consume oxygen, when sewage passes through the biomembranes on the surface of the filler, the sewage is fully transferred with pollution factors to carry out aerobic degradation and nitration reaction, and denitrification reaction is realized in an anoxic unit.

In the specific implementation, during detection:

taking water to the oil-separating sedimentation tank of the sewage station, discharging the water, removing animal and vegetable oil and suspended matters carried in the wastewater by demulsification air flotation, and collecting the wastewater into a SHARON device collecting tank. The waste water in the collection pool of the SHARON device is pumped into the SHARON pool through a SHARON water inlet pump according to a SHARON operation program. The SHARON device is composed of a collecting pool, a SHARON pool and a rear storage pool.

In SHARON pool, in a certain proportionUnder the conditions of pH, temperature and dissolved oxygen, the nitrosobacteria have high removal rate on ammonia and convert the ammonia into NO₂-N. SHARON is the control of the nitration process to NO₂The N stage is terminated, and then denitrification is directly carried out, so that short-cut nitrification and denitrification are realized, and the aim of quickly removing nitrogen is fulfilled. The SHARON operation mode is a Sequencing Batch Reactor (SBR) operation mode, organic matters and ammonia nitrogen in the wastewater are degraded and removed by microorganisms (divided into two stages of nitrification and denitrification) in a SHARON pool, supernatant after precipitation is controlled by an electromagnetic valve in time and automatically flows into a rear storage pool, and the wastewater in the rear storage pool is pumped into a hydrolysis device through a hydrolysis water inlet pump.

The hydrolysis device creates a certain anoxic environment for the wastewater, hydrolysis acidification reaction is carried out, only the anaerobic primary stage is carried out in the process, namely, part of organic matters with difficult degradation of macromolecules are decomposed into organic matters with easy degradation of micromolecules, a carbon source is provided for the subsequent biological denitrification process, and the adding amount of the carbon source is reduced.

The effluent of the hydrolysis device automatically flows to an A/O device, and the A/O device consists of a denitrification tank, a nitrification tank and a secondary sedimentation tank.

The denitrification tank is in an anoxic state, a submersible stirrer is arranged in the denitrification tank, and effluent automatically flows to the nitrification tank. An aeration system is arranged in the nitrification tank, a large amount of microorganisms (activated sludge) are fully contacted with substrates (degradable organic matters in wastewater and the like) in the nitrification tank, and oxidation of carbon-containing organic matters, ammoniation of nitrogen-containing organic matters and nitrification of ammonia nitrogen are generated. The mixed liquid in the nitrification tank flows back to the denitrification tank, and NO in the mixed liquid flows back₃And the-N utilizes the carbon-containing organic matters in the raw wastewater as carbon source substances to carry out denitrification reaction in a denitrification tank under the action of denitrifying bacteria.

The secondary sedimentation tank carries out mud-water separation on effluent of the nitrification tank, sludge at the bottom returns to the denitrification tank, the sludge concentration of the whole A/O biological reaction tank is increased, and the nitrification and denitrification reaction efficiency is improved; and the supernatant of the secondary sedimentation tank automatically flows into an ABFT device.

The ABFT pool is divided into 4 grids, namely an anoxic zone, an aerobic zone, an anoxic zone and an aerobic zone which are sequentially provided with net-shaped wide-hole fillers. A large amount of biological films and activated sludge zoogloea attached on the filler are in a suspension state in water, aeration is carried out at the bottom of the reactor to provide filler fluid power and reaction oxygen consumption, when sewage passes through the biological films on the surface of the filler, the sewage is fully transferred with mass with pollution factors to carry out aerobic degradation and nitration reaction, and denitrification reaction is realized in an anoxic unit.

The final sedimentation tank carries out mud-water separation on the effluent of the ABFT tank, the sludge at the bottom returns to the front end of the ABFT tank, the sludge concentration of the ABFT tank is increased, and the nitrification and denitrification reaction efficiency is improved; and the supernatant of the final sedimentation tank automatically flows into the clear water tank and can be discharged after reaching the standard.

Firstly, a pretreatment process:

because the kitchen waste wastewater contains (light oil) vegetable oil, animal oil (beef tallow, lard) and a large amount of suspended matters in the wastewater, the kitchen waste wastewater must be coagulated and floated, and emulsified oil and dispersed oil must be demulsified. Therefore, the wastewater pretreatment adopts a demulsification coagulation air flotation process, and is also the most effective method for the wastewater pretreatment.

The main mechanism for separating emulsified oil from waste water is to make it lose its emulsification stability, so-called emulsion breaking. The commonly used chemical demulsification method is to add chemical reagents into the wastewater, destabilize and demulsify the emulsion through chemical action, and realize the purpose of oil-water separation.

Coagulation is to electrically neutralize, destabilize and coagulate colloidal particles and hydrophilic pollutants in sewage, flocculate hydrophobic organic matters and micro suspended matters, form macroscopic alum flocs on the microscopic particles, and then realize sludge-water separation by gravity settling or dissolved air floating so as to remove COD, BOD, SS, chromaticity, heavy metal elements and the like in water. The combined technology of the coagulation technology and the air flotation or precipitation technology is mature, the treatment effect is good, and the method has wide application in the field of wastewater treatment.

Generally, the agents which destabilize and coagulate the micelles are called coagulants, while the agents which promote the coagulation effect are called flocculants or coagulant aids, which do not perform the coagulation independently. Inorganic coagulants commonly used include aluminum salts and iron salts, such as polyaluminum chloride (PAC), Poly Ferric Sulfate (PFS), polyaluminum sulfate (PAS), ferric trichloride, etc., and organic polymeric flocculants include Polyacrylamide (PAM), etc. According to the existing black stoneThe operation condition and engineering experience of the sewage treatment station of the kitchen waste plant adopt the demulsifier as FeCl₃The coagulant is PAC and the coagulant aid is PAM (cationic).

Test of dosage of drug

1. Water sample source

The water sample of the pretreatment coagulation test is taken from the water outlet of the oil separation tank of the kitchen waste sewage treatment station. The COD6310mg/L, ammonia nitrogen 1410mg/L, animal and vegetable oil 316mg/L, SS3455mg/L and animal and vegetable oil 415mg/L of the water sample are measured.

2. Test agent

The demulsifier is FeCl₃The coagulant is PAC and the coagulant aid is PAM (cationic).

3. Test method

The experiment adopts a static beaker experiment, and the coagulation experiment research is carried out on the water sample. Taking 1L of water sample in a beaker, stirring the water sample uniformly, adding a demulsifier, stirring for 5min, adding PAC, stirring for 5min, adding PAM, stirring rapidly for 2min, stirring slowly for 10min, standing for 30min, taking supernatant, measuring COD (chemical oxygen demand), SS (suspended substances) and animal and vegetable oil, analyzing, and determining the optimal dosage of the medicament according to the removal rate of each index.

4. Quadrature test

(1) Selecting factors: through a single factor test, the influence of the dosage of the demulsifier, the dosage of PAC and the dosage of PAM on the flocculation effect is found to be more important, so that the three factors are selected in the test as the factors of the orthogonal test.

(2) Horizontal selection: the levels of the three factors are selected to be 3 according to the levels of the factors in the single-factor test, and the maximum level covers the range of adding the medicament when the kitchen wastewater is treated in the existing engineering.

(3) Factor level table: the three factors are selected in the test, each factor is selected to be 3 levels, an orthogonal test is carried out, and the factor levels are shown in a table 4-1.

(4) Test evaluation indexes are as follows: the coagulation treatment effect indexes of the test are COD removal rate, SS removal rate and animal and vegetable oil removal rate.

TABLE 4-1 orthogonal test factors and horizon

5. Test results

The results of the demulsifier, PAC and PAM orthogonal coagulation tests and the results of visual analysis according to the test results are shown in tables 4-2 and 4-3.

TABLE 4-2 Quadrature test results

Table 4-3 visual analysis results table

As can be seen from the range R values in tables 4-3, the preferred level is selected as apparent A3B2C3, i.e., FeCl₃The optimal dosage is 2g/L, the optimal dosage of the PAC coagulant is 1g/L, and the optimal dosage of the PAM coagulant aid is 0.1 g/L.

6. Air flotation test method

(1) And (3) filling clear water in the air floatation device, starting the air floatation device, and adjusting the air floatation device to be in the optimal dissolved air state.

(2) Opening water inlet pump (water is taken from oil separation tank and water is discharged), adding medicine pump (including demulsifier adding medicine pump, PAC adding medicine pump and PAM adding medicine pump), adjusting water inflow and maintaining at 1m³About/h, and simultaneously respectively adjusting demulsifier FeCl₃The adding amount is 2g/L, the adding amount of the coagulant PAC is 1g/L, and the adding amount of the coagulant aid PAM is 0.1 g/L. Meanwhile, the gas stirring valve is adjusted to ensure that the medicament and the sewage are quickly mixed and reacted, but the reaction is not too large, so that the generated floc is prevented from being scattered.

(3) And after the air floatation device operates stably for about half an hour, the previously added clean water basically flows out, and monitoring data of raw water and air floatation effluent before entering the coagulation device are taken.

And tables 4-4 show the removal of COD, SS, animals and plants by the demulsification, coagulation and air flotation device under the same working conditions at different time intervals.

TABLE 4-4 demulsification coagulation air flotation pilot plant monitoring data

In the test, the air flotation effluent is changed from original black to mud color without granular suspended matters. As shown in the table 4-4, the removal rate of COD by demulsification and coagulation air flotation is 10.12-14.47%, the removal effect is relatively stable, and the average removal rate is 12.35%; the removal rate of SS is 96.99-98.5%, and the average removal rate is 97.72%; the removal rate of the animal and vegetable oil is 84.66-93.2%, and the average removal rate is 91.68%.

FeCl of air floatation device₃The adding amount is 2g/L, the adding amount of the coagulant PAC is 1g/L, and the adding amount of the coagulant aid PAM is 0.1 g/L. FeCl₃According to 4 yuan/kg, PAC 2.5 yuan/kg, PAM 15 yuan/kg, the cost of the coagulation air flotation treatment agent is 12 yuan/m³。

The power of the pilot plant pretreatment segment is 2.59kw, the operation is carried out for 4 hours every day, and the power consumption is 9 kw.h every day (the air flotation air compressor operates intermittently). The electric charge is calculated according to 0.8 yuan/kw.h, and the unit electric charge of the pretreatment section is 1.44 yuan/m³. The total running cost of the pretreatment section is 13.44 yuan/m³。

After demulsification and coagulation air floatation, the turbidity of the wastewater is obviously improved, and SS and animal and vegetable oil basically reach the discharge standard. Aiming at the kitchen waste water, the demulsification coagulation air flotation process is feasible after oil removal.

Second, biochemical treatment process

1) SHARON technology

The SHARON process is a short-cut denitrification process developed based on an ammonia oxidation reaction by nitrite bacteria and a nitrite reduction reaction by denitrifying bacteria. For biological denitrification, "NO" in the nitration process₂To NO₃"is a long and complex route, which can be omitted from the process and likewise enables denitrification of the waste water. According to this idea, the industrial university of Delft, the netherlands proposed and successfully developed the SAHRON process in 1997.

Typical features of the SHARON process are:

(1) the short-cut nitrification and the short-cut denitrification are carried out in one reactor, and the process flow is short;

(2) the reactor has simple structure;

(3) the operation temperature is high (30-400 ℃, and the treatment effect is good;

(4) the pH value is regulated and controlled by means of denitrification, and alkali is not required to be added for neutralization.

The microbiological principle of the short-cut nitrification process is realized by mainly utilizing the differences of substrate specificity, multiplication time difference, dependence of growth on substrate concentration and the like of nitrosobacteria and nitrobacteria. Compared with the whole-course nitrification denitrification, the SHARON short-course nitrification denitrification has the following advantages:

(1) the two stages of nitrification and denitrification are completed in the same reactor, so that the flow can be simplified;

(2) the acidity produced by nitration can be partially neutralized by the base produced by denitrification;

(3) the Hydraulic Retention Time (HRT) can be shortened, and the volume and the occupied area of the reactor are reduced;

(4) can save the additional carbon source required by the denitrification process, such as methanol, NO_2-Denitrification ratio NO_3-The denitrification can save 40% of carbon source;

(5) the air supply amount can be saved by about 25 percent, and the power consumption is saved;

(6) the sludge amount is reduced by 50%.

Therefore, the short-cut nitrification of SHARON has obvious advantages for the denitrification treatment of the low-carbon high-nitrogen wastewater.

The key to achieving short-cut nitrification is the achievement of NO during the nitrification stage₂The accumulation of N, the operation temperature of the SHARON process is preferably 30-35 ℃, the pH value is controlled according to the inhibition range of free ammonia on nitrite bacteria, the concentration of dissolved oxygen is controlled within the range of 1.0-1.5 mg/L, and the nutrient supply formulaThe formula adopts intermittent aeration. The concentration of free ammonia in the substrate is regulated within the range of 5-10 mg/L, which is favorable for realizing short-cut nitrification, the ammonia load of the sludge (measured by VSS) is 0.02-0.07 kg/(kg.d), and the sludge age is 1-2.5 days. A large number of experiments show that under the conditions of high wastewater temperature and low DO, the nitrite bacteria with low growth rate are washed away by utilizing different growth speeds of the nitrite bacteria and the nitrifying bacteria and controlling the hydraulic retention time, so that a large number of nitrite bacteria are accumulated, and the short-cut nitrification can be successfully operated.

At present, the short-cut nitrification process is mainly in a laboratory research stage, is not applied to a large-scale operation example, is particularly applied to kitchen waste water, and the temperature and the Dissolved Oxygen (DO) are strictly controlled in the SHARON process. Two wastewater biological denitrification treatment plants utilizing the patent process are built in the Netherlands, and the feasibility of short-range nitrification-denitrification is proved. However, the process realizes the short-cut nitrification by utilizing the characteristic of higher temperature of the digested sludge digestive liquid, which is not significant for most municipal engineering, because a large amount of water is heated and is difficult to realize at the temperature of 30-40 ℃. But has important practical significance for biological denitrification treatment of high ammonia nitrogen wastewater with higher water inlet temperature (the biogas slurry is fermented at high temperature, and the temperature of the biogas slurry discharged by a fermentation tank is about 50 ℃).

The experiment SHARON method is carried out in a simple aerobic reactor, adopts a similar UBR sequencing batch operation mode, and is divided into a periodic treatment mode consisting of 4 steps of aeration nitrification, anoxic denitrification, precipitation and supernatant discharge.

2) Hydrolysis acidification process

Hydrolytic acidification is a biodegradation process under facultative conditions, and some complex insoluble organic substances (including polymers) are converted into simple soluble monomer or dimer compounds in the hydrolytic acidification process, such as starch which is hydrolyzed into glucose in water, protein which is hydrolyzed into dipeptide or amino acid, and the like. After the hydrolysis reaction occurs, the polarity, solubility and the like of organic molecules can be changed, so that the subsequent biochemical treatment is well promoted, and the COD is also removed at a certain rate in the hydrolysis acidification process.

The total hydraulic retention time of the hydrolysis acidification in the experiment is 52h, the operation is continuous, and the hydrolysis acidification is carried out under the anoxic condition.

3) A/O nitrification and denitrification process

The A/O process (anoxic-aerobic activated sludge process) arranges an anoxic denitrification reactor in front of an aerobic reactor, so the A/O process is often called a front-mounted denitrification biological denitrification system, and when waste water needs to simultaneously remove organic matters and denitrify the waste water, the A/O process is a more classical process adopted in practical engineering.

The denitrification refers to that nitrate nitrogen and nitrite nitrogen are reduced and converted into molecular nitrogen (N) by microorganisms under the anaerobic or hypoxia condition₂) The process of (1). The microorganisms involved in this action are denitrifying bacteria, a heterotrophic type of facultative anaerobic bacteria, which utilize organic carbon sources as electron donors under anoxic conditions (DO less than 0.5mg/L), N0₃the-N is taken as an electron acceptor, and denitrification is carried out while organic matters are degraded, and the reaction process can be represented by the following formula:

NO₂ ^-+3H (electron donor) → 0.5N₂+H₂O+OH-

NO₃ ^-+5H (electron donor) → 0.5N₂+H₂O+OH-

The denitrification process can be summarized as follows:

NO₃-→NO₂-→NO→N₂O→N₂

the A/O method is mainly characterized in that a denitrification reactor (anoxic tank) is arranged at the front end of the process, a comprehensive aerobic reactor (aerobic tank) for removing COD and carrying out nitration reaction is arranged at the rear end of the process, raw sewage sequentially enters the anoxic tank, the aerobic tank and the sedimentation tank, and simultaneously, mixed liquor in the aerobic tank and sludge in the sedimentation tank are returned to the anoxic tank, so that organic matters in the raw sewage can be directly used as an organic carbon source during the denitrification reaction, and nitrate in the mixed liquor containing the nitrate returned from the aerobic reactor is denitrified into nitrogen. The alkalinity generated in the denitrification reactor due to the denitrification reaction can enter the aerobic nitrification reactor along with the effluent water, and about half of the alkalinity required to be consumed in the nitrification reaction process is compensated. The aerobic nitrification reactor is arranged at the rear end of the process, and can further remove the residual organic matters in the denitrification process.

4) ABFT process

The aeration biological fluidization tank aerobiological fluidization and DTank (ABFT for short) process is a new sewage treatment technology for biochemical denitrification. The process integrates medium fluidization, adsorption and biochemical processes, is relatively complex in operation mechanism, and is convenient to operate and manage and simple to operate. In particular, the combination of the physical and chemical method and the biological method simultaneously takes the advantages of the activated sludge method, the biofilm method and the immobilized microorganism technology into consideration, so that the water treatment method has been paid more and more attention by the water treatment field.

A high-efficiency microorganism carrier accounting for 40-60% of the effective volume of an aeration tank is added into the Aeration Biological Fluidization Tank (ABFT), so that a large number of microorganisms are attached and fixed on the high-efficiency microorganism carrier. In each stage of ABFT pool, the degradation effect of the target pollutants is improved by culturing different strains with special effects and advantages step by step; the survived microorganisms are adsorbed on the carrier, the adsorbed microorganisms are not easy to fall off and run off, and the high-load biomass ensures the high efficiency and stability of removing pollutants by the ABFT process.

Process characteristics

As a novel efficient and stable sewage treatment process, the ABFT has the following characteristics:

(1) the denitrification effect is good. The microorganisms are adsorbed on the carrier, more nitrifying bacteria are attached to the surface of the carrier under an aerobic condition, more denitrifying bacteria are attached to the surface of the carrier under an anoxic condition, the sludge age of the carrier can reach more than 60 days, and the good denitrification effect is achieved.

(2) High processing load and small occupied area.

(3) And (5) grading treatment. The ABFT process tank body design usually mainly adopts small-grid multi-stage design. With the decreasing of the concentration of the pollutants in the water, the dominant microbial community suitable for the environment of the pond can be conveniently cultured in different pond bodies, and the external environment of the pond can be conveniently adjusted and controlled, so that the treatment efficiency is improved.

(4) And (5) modular management. When the production process is limited by seasonality or the follow-up equipment maintenance needs to be stopped, the ABFT biochemical process can be put down to sleep so as to reduce the operation cost; when used again, the ABFT biochemical system can be started quickly in a short time.

(5) No sludge expansion is generated, and the sludge yield is small. Besides fungi, filamentous fungi and zoogloea, microorganisms on the biological carrier also comprise a plurality of protozoa and metazoans for catching bacteria, so that a stable food chain is formed, the generated sludge is small, the sludge does not expand, and the management is easy.

(6) The effluent quality is good and stable. Compared with the processes such as a contact oxidation method, a biomembrane method, BAF and the like, the ABFT process has stable operation and good and stable effluent quality. Is particularly suitable for the advanced treatment process of industrial wastewater treatment and reclaimed water recycling.

(7) The cost is low. Compared with the traditional process, the investment cost and the operation cost are both low.

Third, biochemical treatment operation mode

In order to facilitate rapid development of pilot-scale research, pilot-scale sludge of a pilot-scale device is taken to a black stone kitchen waste sewage treatment station, wherein sludge of a SHARON device is taken to a sewage station MBR nitrification tank, sludge of a hydrolysis device is taken to a sewage station hydrolysis tank, and sludge of an A/O device and an ABFT device are also taken to the sewage station MBR nitrification tank. And (3) connecting a DN20 rubber hose with a submersible pump, pumping into a corresponding pilot plant, and filling the corresponding pilot plant.

And rapidly recovering the full-load operation of the biochemical treatment device according to the relevant operation parameters of the pilot plant test scheme. Theoretically, the reflux (internal reflux) of the mixed liquid of the A/O device is increased, the denitrification effect is improved, but the growth of the microbial flora in the anoxic pond is influenced by the overlarge internal reflux ratio. According to the actual operation experience of the black stone kitchen waste sewage treatment station, the in-test reflux ratio in the stage is 8 times; and (3) sludge backflow (external backflow), namely, the mixed liquor flows back from the aerobic tank to the anaerobic tank for anaerobic phosphorus release so as to achieve the effect of phosphorus removal, and simultaneously the concentration of activated sludge in the biological tank is ensured, the external backflow ratio is 2 times, and sludge is not discharged at the initial debugging stage. The ABFT reflux pump runs intermittently and refluxes from the aerobic zone of the 4 th grid to the anoxic zone of the 1 st grid, and the reflux ratio is 2 times. The fan runs all day long, the proper air quantity is adjusted, and the redundant air quantity is discharged.

The A/O device keeps the pH value of the O pool to be maintained above 6.5 by adding an alkali sheet; according to the inlet water concentration COD/NH of A/O device₃Determining the amount of a carbon source added into the tank A by the ratio of-N, wherein the carbon source is solid glucose, and the water inlet concentration COD/NH of the A/O device after the carbon source is added₃The ratio of-N is kept above 5. The SHARON device is positioned at the foremost end of the process, and the carbon source and the alkaloid are sufficient, and the carbon source and the alkali pieces are not added; after the carbon source is added into the A/O device, the COD of the ABFT device is sufficient, and the carbon source and the alkali pieces are not added.

Gradually increasing the water quantity to 5m³And after/d, starting to monitor the water quality of inlet and outlet water of each treatment device, and determining the process feasibility.

The pilot plant runs for a half month at full load, and each plant determines the feasibility of each plant for treating the wastewater according to the removal rate of COD, ammonia nitrogen and total nitrogen.

1) SHARON device

The removal rate of COD, ammonia nitrogen and total nitrogen by the SHARON device is shown in the table 5-1.

5-1SHARON device removal Rate

As can be seen from Table 5-1, the average removal rate of COD by the SHARON unit was 30.57%, the average removal rate of ammonia nitrogen was 24.89%, and the average removal rate of total nitrogen was 29.84%.

2) Hydrolysis device

The removal rate of COD, ammonia nitrogen and total nitrogen by the hydrolysis device is shown in the table 5-2.

5-2 hydrolysis apparatus removal Rate

As seen from Table 5-2, the hydrolysis apparatus had an average removal rate of COD of 26.36%, an average removal rate of ammonia nitrogen of 5.57%, and an average removal rate of total nitrogen of 0.40%.

3) A/O device

The removal rates of COD, ammonia nitrogen and total nitrogen by the A/O device are shown in tables 5-3.

5-3A/O device removal rate

Note: the COD of the inlet water of the A/O device is the COD value of the carbon source which is not added, and the COD of the outlet water is the COD value of the added carbon source.

As seen from tables 5 to 3, the average removal rate of COD by the A/O apparatus was 51.91% (not taking into account the removal rate of the carbon source), the average removal rate of ammonia nitrogen was 84.38%, and the average removal rate of total nitrogen was 58.26%. The average daily dosage of the carbon source (solid glucose) is 16.8kg, and the average daily dosage of the alkali tablet (for supplementing the nitrification alkalinity) is 5.6 kg.

4) ABFT device

The removal rates of COD, ammonia nitrogen and total nitrogen by the ABFT device are shown in tables 5-4.

5-4ABFT plant removal Rate

From tables 5-4, it can be seen that the average removal rate of COD by the ABFT device is 74.52%, the average removal rate of ammonia nitrogen is 76.58%, and the average removal rate of total nitrogen is 14.45%.

The pilot plant was run at full capacity (processing capacity up to 5m per day)³After the/d), 6 groups of data are monitored within a half month, and feasibility of removal effect of each device of the kitchen waste and wastewater is analyzed.

Through final effluent analysis, the average COD concentration is 314mg/L, and all monitoring data reach the standard; the average concentration of ammonia nitrogen is 26mg/L, and all monitoring data reach the standard; the average concentration of total nitrogen is 412mg/L, and the total nitrogen yield is higher. Aiming at the kitchen waste wastewater, the process can basically enable COD and ammonia nitrogen to run up to the standard.

The above description is only exemplary of the present invention and should not be taken as limiting, and any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A kitchen waste wastewater non-membrane treatment method is characterized by comprising the following steps:

A. firstly, a processing system with the following structure is obtained: comprises a pretreatment system (1) for removing suspended matters, animal and vegetable oil and partial COD in the wastewater and a biochemical treatment system (2) for performing denitrification treatment on the wastewater; the pretreatment system (1) comprises a demulsification and coagulation device (11); the biochemical treatment system (2) comprises a SHARON device (21) for short-range denitrification, a hydrolytic acidification device (22) for hydrolyzing and acidifying insoluble organic matters into soluble monomer or dimer compounds, an A/O device (23) for denitrifying biological denitrification and an ABFT device (24) for biochemical denitrification which are sequentially connected; the water inlet of the SHARON device (21) is connected to the water outlet of the demulsification and coagulation device (11);

B. the kitchen waste wastewater flows into a demulsification and coagulation device to remove suspended matters, animal and vegetable oil and dissolved oxygen in the wastewater; then enters a SHARON device for nitrogen removal, and then flows into a hydrolysis acidification device to decompose macromolecular organic matters in the wastewater into micromolecular organic matters; then the mixture enters an A/O device for nitration/denitrification reaction, finally enters an ABFT device for biochemical denitrification and then is precipitated, and the supernatant flows out;

in the step A, the pretreatment system (1) further comprises an oil separation sedimentation tank (12) arranged at the front end of the demulsification and coagulation device (11), and a grid (121) for filtering large-particle solid pollutants is arranged in the oil separation sedimentation tank (12);

the three grids (121) are sequentially arranged, and the aperture of each grid is gradually reduced along the water inlet direction;

the oil separation sedimentation tank is characterized in that a plurality of guide plates (122) which are parallel to each other and arranged at intervals are arranged in the oil separation sedimentation tank (12), one end of each guide plate (122) is fixed on the inner wall of the oil separation sedimentation tank (12), the other end of each guide plate is separated from the inner wall of the oil separation sedimentation tank (12) to form a flow passage, and the flow passages on two adjacent guide plates are respectively positioned on two sides of the length direction of each guide plate, so that an S-shaped flow passage is formed in the oil separation sedimentation tank (12).

2. The kitchen waste and wastewater non-membrane treatment method according to claim 1, wherein in the step A, the demulsification and coagulation device (11) comprises an air flotation tank (111) for treating wastewater, a demulsifier tank (112) for storing demulsifier, a coagulant tank (113) for storing coagulant and a coagulant aid tank (114) for storing coagulant aid; the system comprises a demulsifier tank (112), a coagulant tank (113) and a coagulant aid tank (114), wherein the demulsifier tank, the coagulant tank (113) and the coagulant aid tank (114) are respectively connected to an air floatation tank (111) through dosing pumps, an air stirring device for stirring is arranged in the air floatation tank (111), and the air stirring device is connected to an air source through a pipeline provided with a valve.

3. The non-membrane treatment method for kitchen waste wastewater according to claim 1, characterized in that in step A, the SHARON device (21) comprises a collection tank (211) for collecting wastewater, a SHARON tank (212) for nitrification/denitrification nitrogen removal and a post-storage tank (213) for temporarily storing nitrogen-removed wastewater; a SHARON water inlet pump for pumping water is connected between the collection pool (211) and the SHARON pool (212); an overflow pipe convenient for supernatant to flow out is connected between the upper part of the SHARON pool (212) and the rear storage pool (213), and an electromagnetic valve for controlling the on-off of the overflow pipe is arranged on the overflow pipe.

4. The kitchen waste wastewater non-membrane treatment method according to claim 1, wherein in the step A, the A/O device (23) comprises a denitrification tank (231), a nitrification tank (232) and a secondary sedimentation tank (233), wherein a water outlet of the denitrification tank (231) is connected to a water inlet of the nitrification tank (232), the nitrification tank (232) is provided with a first return port connected to the denitrification tank (231), a water outlet of the nitrification tank (232) is connected to the secondary sedimentation tank (233), the bottom of the secondary sedimentation tank (233) is provided with a second return port for returning sludge, and the second return port is connected to the denitrification tank (231).

5. The non-membrane treatment method for kitchen waste wastewater according to claim 4, characterized in that in step A, the ABFT device (24) comprises an ABFT tank (241) for biochemical denitrification, a final sedimentation tank (242) for sludge-water separation and a clear water tank (243) for temporarily storing supernatant of the final sedimentation tank, the bottom of the final sedimentation tank (242) is provided with a third return port for sludge return, the third return port is connected to the ABFT tank (241), the upper end of the final sedimentation tank (242) is provided with a liquid outlet for supernatant overflow, and the liquid outlet is connected to the clear water tank (243).

6. The non-membrane treatment method for kitchen waste and wastewater according to claim 5, characterized in that in step A, the ABFT tank (241) is provided with two anoxic zones and two aerobic zones which are sequentially arranged at intervals, net-shaped wide-hole fillers are arranged in the anoxic zones and the aerobic zones, and a large amount of biomembranes and activated sludge zoogloea are attached to the fillers; and a third aeration device is also arranged in the aerobic zone.