Coffee bean fermentation wastewater treatment system

Abstract

The present application discloses a coffee bean fermentation wastewater treatment system, including: a primary filter tank, a pH value adjustment tank, a flocculation flotation tank, a neutralization tank, a biochemical treatment integrated device, and an MBR membrane treatment tank; the primary filter tank is connected to the liquid inlet pipeline of the pH value adjustment tank; the liquid outlet of the pH value adjustment tank is connected to the liquid inlet pipeline of the dosing area of ​​the flocculation flotation tank; the liquid outlet of the dosing area of ​​the flocculation flotation tank is connected to the flotation area pipeline; an air inlet pipe is inserted in the flotation area; a liquid outlet is set at the lower part of the flotation area, and is connected to the liquid inlet of the neutralization tank pipe; an aeration pipe is inserted inside the neutralization tank; the liquid outlet of the neutralization tank is connected to the liquid inlet pipeline of the biochemical treatment integrated device. By adding a reagent, the suspended matter in the wastewater is formed into a flocculent state, and after being attached to the bubbles in the flotation area, it is lifted to the liquid surface with the floating bubbles and is scraped off in time, without stopping the machine to clean up the sludge or flocculent, and the treatment efficiency is greatly improved, which is suitable for the season with a large amount of wastewater treatment in the production season.

Description

Technical Field

[0001] The present application relates to the technical field of coffee bean contaminated wastewater treatment, and in particular to a coffee bean fermentation wastewater treatment system. Background Art

[0002] After coffee berries are picked, they need to go through enzymatic hydrolysis or fermentation, drying and other primary processing to form commercial beans. There are three main methods for primary processing of coffee berries: wet processing, dry processing and semi-dry processing. More than 80% of the primary processing of coffee berries in Yunnan Province adopts wet processing.

[0003] Wet processing consumes a lot of water, and the wastewater produced is highly acidic, rich in a large amount of suspended non-oily organic matter and nitrogen and phosphorus nutrients, and highly toxic. Direct discharge into rivers will cause eutrophication of water bodies and lead to the death of a large number of aquatic organisms. For example, the test results of wastewater produced by a batch of production, the wastewater produced by wet production of coffee cherries: pH value 3.8, suspended solids content 300mg / L, chromaticity 200, five-day biochemical oxygen demand COD cr 3763mg / L, total nitrogen content is 92.5mg / L, total phosphorus content is 12.58mg / L, and ammonia nitrogen content is 48.41mg / L.

[0004] In addition, the total wastewater contains a high content of suspended solids, especially after the pectin layer between the fruit body and the peel is removed by wet production, and the wastewater is directly discharged for irrigation. The fermented and decomposed pectin will precipitate from the wastewater, forming a crust on the surface, blocking waterways, forming an anaerobic environment on the surface, and affecting the land ecology. If the wastewater enters the daily water supply, it will cause dizziness, breathing difficulties, skin discomfort and other problems for users.

[0005] In order to reuse the organic matter contained in coffee wastewater, coffee wastewater needs to be treated and meet the requirements of the "Pollutant Discharge Standard for Urban Wastewater Treatment Plants" (GB18918-2002) before it can be discharged and recycled. In order to meet the discharge requirements, in the prior art, coffee wastewater is often preliminarily filtered to remove excessive volume waste, and then centrifugal separation and filtration are used to remove impurities. The separated and filtered wastewater is sent to the regulating tank for mixing, and the mixed wastewater is sent to the ZC electrocatalytic device for pulse current shock and electrocatalytic treatment. The ZC electrocatalytic device cooperates with the precipitator to oxidize the wastewater to produce sludge, which is input into the sludge concentration tank, treated by the sludge dewatering machine and then transported for external treatment. The wastewater without sludge is input into the biochemical treatment unit, and after anoxic, aerobic, and anaerobic microorganisms decompose the organic matter in the water, it is treated by the MBR membrane pool and sent to the clean water tank for disinfection before being discharged in compliance with the standards. For example, the coffee processing wastewater treatment process disclosed in CN202010395288.2.

[0006] This process mainly uses ZC electrocatalytic equipment, and utilizes electrochemical principles to degrade and modify organic pollutants in wastewater, while simultaneously undergoing physical and chemical separation reactions such as electrical flotation and electrical coagulation to achieve treatment. The centrifugal filtration operation in the pre-treatment of this method is more difficult to handle during production seasons with large amounts of wastewater discharge, and the cost of the equipped centrifuge is increased. In addition, after a period of use, the sludge in the centrifuge needs to be cleaned, which affects the efficiency of wastewater treatment.

[0007] Although this method is used to treat coffee production wastewater with CODcr below 15000mg / L, and the CODcr in the treated water can be reduced to below 100mg / L, it cannot reach the required content for discharge when used to treat wastewater with CODcr greater than 15000mg / L.

[0008] The above-mentioned prior art does not disclose the quality of the treated water. If it cannot meet the requirements for farmland water use, it cannot be discharged directly, which will affect the sewage treatment effect and the COD value and suspended matter content in the treated water, resulting in the water being unable to be directly returned to the fields for use after treatment.

[0009] This method cannot achieve automatic and effective cleaning of solid wastes such as sludge generated after centrifugal filtration.

[0010] The existing flotation sewage treatment equipment is divided into two areas. The dosing area is used to add coagulants and flocculants and stir them evenly to produce flocs. The flotation area introduces compressed air to the water outlet, and uses the bubbles generated by the gas in the water to float up and drive the flocs to float with the bubbles to complete the separation of the flocs from the water. Before using this equipment, the solid impurities contained in the water must be filtered, and it cannot directly treat wastewater with a large content of suspended matter.

[0011] On the other hand, the existing flotation zone outlet pipe mainly discharges gas directly into the water body through the pipe body, which can easily cause the wastewater to boil and bubble. Due to the excessive content of suspended matter, the existing ventilation pipe is prone to produce aeration bubbles that affect the bubble volume. If the bubble volume is too large, it will reduce the flotation removal effect of flocculants, and the water quality after treatment is difficult to meet the discharge standards. Summary of the invention

[0012] The present application provides a coffee bean fermentation wastewater treatment system, which is used to solve the technical problem in the prior art that the coffee wastewater with suspended matter content and CODcr greater than 15000 mg / L cannot meet the Class A standard in the "Pollutant Discharge Standard for Urban Wastewater Treatment Plants" (GB18918-2002) after treatment using the existing method.

[0013] The present application provides a coffee bean fermentation wastewater treatment system, which is used to solve the technical problems in the prior art that the removal of suspended matter by centrifugal filtration is difficult to operate, batch processing is required, and the filter plate needs to be cleaned multiple times, resulting in reduced wastewater treatment efficiency.

[0014] The present application provides a coffee bean fermentation wastewater treatment system, including: a primary filtration tank, a pH adjustment tank, a flocculation flotation tank, a neutralization tank, a biochemical treatment integrated device, and an MBR membrane treatment tank;

[0015] The primary filter tank is connected to the liquid inlet pipeline of the pH value adjustment tank; the liquid outlet of the pH value adjustment tank is connected to the liquid inlet pipeline of the dosing area of ​​the flocculation flotation tank; the liquid outlet of the dosing area of ​​the flocculation flotation tank is connected to the pipeline of the flotation area; an air inlet pipe is inserted in the flotation area; a liquid outlet is set at the lower part of the flotation area and is connected to the liquid inlet of the neutralization tank pipe; an aeration pipe is inserted inside the neutralization tank; the liquid outlet of the neutralization tank is connected to the liquid inlet pipeline of the biochemical treatment integrated device;

[0016] The biochemical treatment integrated device is connected with the liquid inlet pipeline of the MBR membrane treatment tank;

[0017] A filter screen is arranged on the top surface of the primary filter tank; the wastewater in the pH adjustment tank is neutralized with lime water to a pH value of 6 to 9;

[0018] The dosing area is provided with dosing pipes in pairs, and the dosing pipes are used to introduce flocculants and coagulants respectively.

[0019] The filter mesh number of the filter is 5 to 15 meshes;

[0020] The pH value of the wet primary processing coffee cherry wastewater is greater than 3.8, the suspended matter content is less than 300 mg / L, the chromaticity is less than 200, the chemical oxygen demand CODcr is less than 16000 mg / L, the five-day biochemical oxygen demand BOD5 is less than 4000 mg / L, the total nitrogen content is less than 100 mg / L, the total phosphorus is less than 13 mg / L, and the ammonia nitrogen content is less than 50 mg / L.

[0021] Preferably, the biochemical treatment integrated device comprises: a Class A oxidation tank, a Class O biological tank, a Class O biochemical treatment tank, and a secondary sedimentation tank; the Class A oxidation tank is connected to the neutralization tank through a liquid outlet pipeline; the Class A oxidation tank, the Class O biological tank, the Class O biochemical treatment tank, and the secondary sedimentation tank are connected in series in sequence through pipelines;

[0022] It includes: a sludge pool, the liquid inlet of the sludge pool is connected with the sewage outlet pipelines of the O-level biological pool and the flotation zone respectively, and a sludge pump is arranged on the connecting pipeline; the liquid inlet of the A-level oxidation pool is connected with the supernatant outlet pipeline of the sludge pool.

[0023] Preferably, the flocculation flotation tank comprises: a dosing zone and an air flotation zone; the dosing zone is arranged on one side of the air flotation zone and is connected to the air flotation zone;

[0024] The dosing area includes: a multi-stage overflow area and a liquid outlet area; a dosing group pipe and a main water inlet pipe are arranged on the liquid inlet end of the overflow area; a second overflow plate is arranged on the liquid outlet end of the overflow area, and the top surface of the second overflow plate is connected to the liquid outlet area; a water outlet is arranged on the side wall of the bottom surface of the liquid outlet area, and the water outlet is connected to the liquid outlet area and the air flotation area;

[0025] The flotation area includes: multiple air-adding pipes and a ventilation plate; one end of the air-adding pipe is connected to the compressed air machine; the other end extends into the flotation area and is arranged close to the dosing area; a ventilation plate is arranged on the extending end of the air-adding pipe; the ventilation plate includes: a plate body and an air outlet main pipe; one end of the air outlet main pipe is arranged perpendicular to the side wall of the plate body, and the other end is arranged perpendicular to the side wall of the plate body and extends outward; an end cover is arranged on the extended end of the air outlet main pipe, and a plurality of air outlet microholes are provided on the end cover.

[0026] Preferably, the multi-level overflow area includes: a first overflow area, a second overflow area, and a liquid outlet area; a dosing group pipe and a main water inlet pipe are inserted on the top surface of the first overflow area; a first overflow plate is inserted between the first overflow area and the second overflow area; the second overflow area is arranged below the first overflow area; the top surface of the first overflow plate is arranged below the center line of the side wall of the first overflow area; the liquid outlet area is arranged on the other side of the second overflow area, and the top surface of the liquid outlet area is arranged below the center line of the second overflow area; a second overflow plate is inserted on the connected side walls of the second overflow area of ​​the liquid outlet area;

[0027] A water outlet is provided at the lower part of the side wall adjacent to the liquid outlet area and the air flotation area; the liquid outlet area of ​​the air flotation area is connected through the water outlet.

[0028] Preferably, the first overflow area comprises: an inclined plate; the inclined plate is obliquely arranged on the bottom surface of the first overflow area at an angle of 25-35° to the horizontal plane.

[0029] Preferably, the top surface of the first overflow plate is higher than the top surface of the second overflow plate.

[0030] Preferably, the second overflow area comprises: a baffle plate; the baffle plate is accommodated in the second overflow area and spaced apart from the bottom surface of the second overflow area.

[0031] Preferably, the liquid outlet area comprises: a plurality of flow-blocking strips; the flow-blocking strips are arranged at intervals laterally along the liquid outlet area; a plurality of inverted hooks are arranged on the outer side walls of the flow-blocking strips, and the tips of the inverted hooks are arranged toward the inner side wall of the liquid outlet area.

[0032] Preferably, the ventilation disc comprises: a plurality of outlet branch pipes; one end of the outlet branch pipe is connected to the disc body and extends upward perpendicular to the disc body; a plurality of outlet micro holes are arranged on the extended end of the outlet branch pipe.

[0033] Preferably, the ventilation plate comprises: a plurality of pressure-stabilizing tubes, the pressure-stabilizing tubes being connected to adjacent gas-filling tubes;

[0034] The gas filling pipe includes: a first pipe, a second pipe, and a third pipe; the voltage-stabilizing tube includes: a first voltage-stabilizing tube and a second voltage-stabilizing tube; the first voltage-stabilizing tube is arranged between the adjacent first pipe and the second pipe, and is connected to the first pipe and the second pipe; the second voltage-stabilizing tube is arranged between the adjacent second pipe and the third pipe, and is connected to the second pipe and the third pipe; the first voltage-stabilizing tube is arranged above the second voltage-stabilizing tube.

[0035] The beneficial effects of this application include:

[0036] 1) The coffee bean fermentation wastewater treatment system provided in the present application can destroy the stability of suspended droplets in the water and precipitate them from the water to form floccules by introducing flocculants and coagulants into the wastewater after primary filtration and pH adjustment. The suspended droplets can be effectively destroyed by only introducing the reagents. The treatment capacity depends only on the volume of the flocculation tank. After the wastewater producing floccules enters the flotation tank, it can be lifted to the liquid surface with the floating bubbles generated by the introduced gas and be scraped off in time. There is no need to stop the machine to clean sludge or floccules, and the treatment efficiency is greatly improved. It is suitable for seasons with large wastewater treatment capacity during the production season.

[0037] 2) The coffee bean fermentation wastewater treatment system provided in this application can realize continuous treatment as a whole, has a large treatment capacity, high efficiency, and a small footprint. It can remove suspended solids and insoluble COD contained therein by adding flocculants and coagulants and flotation steps. The process and equipment structure are simple and easy to use and maintain.

[0038] 3) The coffee bean fermentation wastewater treatment system provided by the present application, by setting up a multi-stage overflow zone in the dosing, on the one hand, uses the original flow rate of the pumped water body to achieve the dosing stirring effect in the overflow zone, omitting the setting of a stirring device in the dosing zone, and reducing the overall flow rate of the pumped water body through the subsequent multi-stage overflow plate, so that only the upper layer of clear water enters the next layer of overflow zone, achieving the purpose of preliminary separation of suspended matter. By inserting a steady flow pipe in the water body, the gas outlet stability of the ventilation pipe is improved, and the effect of air flow fluctuations on flotation treatment is reduced. At the same time, a disc-shaped gas outlet disk is set on the bottom surface of the ventilation pipe, and multiple small holes are set at intervals on the top surface of the gas outlet disk to open and then discharge gas towards the top surface, which is conducive to the formation of a large number of tiny bubbles, thereby increasing the amount of alum flowers carried by bubbles and improving the impurity removal effect of flotation operation. By introducing compressed gas into the water body in the flotation tank, excess surfactants and odors in the water can be removed, and the dissolved oxygen content in the water is increased by aeration, providing the required high oxygen content conditions for subsequent microbial decomposition treatment, without the need to set up a separate gas replenishment step.

[0039] 4) The coffee bean fermentation wastewater treatment system provided in this application, after the sewage is added with drugs, enters the flotation mixing area, mixes with the released dissolved air water, makes the floccules adhere to the tiny bubbles, and then enters the flotation area. The floccules float to the water surface under the action of air buoyancy to form scum. After the clean water in the lower layer flows to the clean water tank through the water collector, part of it flows back for dissolved air, and the remaining clean water flows out through the overflow port. After the scum on the water surface of the flotation tank accumulates to a certain thickness, it is scraped into the flotation machine sludge tank by the scraper and then discharged and treated again by the flotation sedimentation integrated machine to ensure that the pretreatment removes the excessive suspended matter in the water.

[0040] 5) The coffee bean fermentation wastewater treatment system provided in the present application removes the above substances in the water through flotation treatment, and the residual difficult-to-decompose organic matter in the water body forms small-volume flocs in the water body, which are biodegraded into small molecular substances with good biodegradability through microbial treatment. The small molecular organic matter can be decomposed and utilized by microorganisms again, thereby achieving effective treatment of coffee wastewater. The treated wastewater meets the national standard requirements of Class A in the "Pollutant Discharge Standard for Urban Wastewater Treatment Plants" (GB18918-2002) (the pH of the discharged water after treatment is 6~9, CODcr≤50mg / L, BOD5≤10mg / L, SS≤10mg / L, ammonia nitrogen content≤5(8)mg / L, total phosphorus≤0.5mg / L, total nitrogen≤15mg / L, the values ​​outside the brackets are the control indicators when the water temperature is>12℃, and the values ​​inside the brackets are the control indicators when the water temperature is≤12℃), thereby achieving repeated recycling of the organic matter contained. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram of the coffee bean fermentation wastewater treatment system provided for this application;

[0042] Figure 2 A schematic diagram of the top view of the flocculation flotation tank provided in this application;

[0043] Figure 3 for Figure 2 AA main view structure diagram;

[0044] Figure 4 for Figure 2 BB main view structure diagram;

[0045] Figure 5 A schematic diagram of the three-dimensional structure of an air outlet head in an embodiment provided in this application;

[0046] Figure 6 A schematic diagram of the three-dimensional structure of a ventilating disk in another embodiment provided in the present application;

[0047] Figure 7 A schematic diagram of the structure of the air outlet pipe provided in this application from a top view;

[0048] Legend:

[0049] 11. flotation zone; 20. first overflow zone; 21. first mounting plate; 211. first dosing pipe; 212. main water inlet pipe; 213. second dosing pipe; 214. inclined plate; 215. first overflow plate; 22. second overflow zone; 221. baffle plate; 222. second overflow plate; 23. liquid outlet zone; 231. baffle strip; 233. water outlet; 24. second mounting plate; 242. air adding pipe; 245. first voltage regulator tube; 246. second voltage regulator tube; 251. ventilation plate; 252. outlet branch pipe; 253. outlet main pipe; 254. end cover; 255. outlet micropores. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0051] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] The technical means that are not described in detail in this application and are not used to solve the technical problems of this application are all set according to the common knowledge in the field, and can be implemented in a variety of common knowledge settings.

[0053] See also Figures 1 to 7 The coffee bean fermentation wastewater treatment system provided in this application includes: a primary filter tank, a pH adjustment tank, a flocculation flotation tank, a neutralization tank, a biochemical treatment integrated device, and an MBR membrane treatment tank;

[0054] The primary filter tank is connected to the liquid inlet pipeline of the pH value adjustment tank; the liquid outlet of the pH value adjustment tank is connected to the liquid inlet pipeline of the dosing area of ​​the flocculation flotation tank; the liquid outlet of the dosing area of ​​the flocculation flotation tank is connected to the pipeline of the flotation area; an air inlet pipe is inserted in the flotation area; a liquid outlet is set at the lower part of the flotation area and is connected to the liquid inlet of the neutralization tank pipe; an aeration pipe is inserted inside the neutralization tank; the liquid outlet of the neutralization tank is connected to the liquid inlet pipeline of the biochemical treatment integrated device;

[0055] The biochemical treatment integrated device is connected with the liquid inlet pipeline of the MBR membrane treatment tank;

[0056] A filter screen is arranged on the top surface of the primary filter tank; the wastewater in the pH adjustment tank is neutralized with lime water to a pH value of 6 to 9;

[0057] The dosing area is provided with dosing pipes in pairs, and the dosing pipes are used to introduce flocculants and coagulants respectively.

[0058] The filter mesh number of the filter is 5 to 15 meshes;

[0059] The pH value of the wet primary processing coffee cherry wastewater is greater than 3.8, the suspended matter content is less than 300 mg / L, the chromaticity is less than 200, the chemical oxygen demand CODcr is less than 16000 mg / L, the five-day biochemical oxygen demand BOD5 is less than 4000 mg / L, the total nitrogen content is less than 100 mg / L, the total phosphorus is less than 13 mg / L, and the ammonia nitrogen content is less than 50 mg / L.

[0060] Flocculant: polyacrylamide; coagulant: polyaluminium chloride; pH adjuster: limestone.

[0061] After the wet primary processing coffee cherry wastewater flows through the filter screen set on the top surface of the primary filter tank, it enters the pH adjustment tank and is neutralized with lime water to an outlet pH value of 6-9; the neutralized wastewater enters the dosing area of ​​the flocculation flotation tank and is mixed with coagulants and flocculants before entering the flotation area; after pressurized air is introduced into the flotation area through the air inlet pipe, the gas flows out from the bubbling nozzle set on the bottom surface of the air inlet pipe and floats to the liquid surface to form scum; the automatic chain scum plate scrapes the scum onto the filter screen at one end of the flotation area, and the scum is discharged regularly after filtering; the use of a 5-15 mesh filter screen can effectively filter solid impurities with a particle size exceeding 5 mesh, and the filter screen is an open structure, which is convenient for regular cleaning.

[0062] The biochemical treatment device used is a commercially available device. It is used to perform microbial and chemical degradation treatment on organic matter contained in sewage. The impurities on the filter screen of the primary filter tank and the solid impurities generated by sedimentation in the pH adjustment tank can be cleaned and transported out manually on a regular basis.

[0063] Preferably, the integrated biochemical treatment device includes: a Class A oxidation tank, an O-class biological tank, an O-class biochemical treatment tank, and a secondary sedimentation tank; the Class A oxidation tank is connected to the neutralization tank through a liquid outlet pipeline; the Class A oxidation tank, the O-class biological tank, the O-class biochemical treatment tank, and the secondary sedimentation tank are connected in series in sequence through pipelines.

[0064] The full name of the Class A oxidation pond used in this application is the Class A oxidation biological contact oxidation pond, which is mainly a high-load biological adsorption section. It uses the adsorption and coagulation characteristics of activated sludge to adsorb organic matter in sewage on the activated sludge in a very short time, and partially degrades it. The generated biological sludge settles in the sedimentation tank attached to the Class A oxidation pond, and part of the clean water is returned to the Class A oxidation pond.

[0065] (1) Class A oxidation pond

[0066] In order to control the dissolved oxygen content of the water in the Class A oxidation pond at about 0.5 mg / l, intermittent aeration is set in the pond to maintain the dissolved oxygen content. Filler balls loaded with microorganisms are set in the Class A oxidation pond. The filler balls are not easy to clog, are light in weight, have a large specific surface area, have a stable treatment effect, and are easy to repair and replace.

[0067] (2) O-level biochemical treatment pool, O-level biological pool

[0068] The filler of the O-level biochemical treatment pool adopts columnar biological carrier filler set in the pool, and aeration equipment is set on the inner wall of the pool wall. The filler has a large specific surface area, which is 16 to 20 times that of general biological fillers (same unit volume), effectively maintaining a high biomass in the pool and achieving the purpose of high-speed removal of organic pollutants. The aeration equipment uses a blower and a microporous aerator to introduce air into the O-level biochemical treatment pool to achieve aeration, so that the utilization rate of dissolved oxygen reaches more than 30%, effectively saving operating costs.

[0069] (3) Secondary sedimentation tank

[0070] After the sewage is treated by O-level biochemical treatment, the water contains a large amount of suspended solids (biofilm shedding). In order to make the effluent SS meet the discharge standards, a vertical flow sedimentation tank is used for solid-liquid separation. One sedimentation tank is set up with a surface load of 1.0m 3 / m 2 •hr. The sludge in the sedimentation tank is lifted to the sludge tank by air lift equipment. At the same time, according to the actual water quality, part of the sludge can be lifted to the A-level oxidation tank for sludge return, increasing the sludge concentration in the O-level biochemical treatment tank and improving the sludge removal efficiency.

[0071] Preferably, it comprises: a sludge tank, the liquid inlet of the sludge tank is connected with the sewage outlet pipelines of the O-level biological tank and the flotation zone respectively, and a sludge pump is arranged on the connecting pipeline; the liquid inlet of the A-level oxidation tank is connected with the supernatant outlet pipeline of the sludge tank.

[0072] The MBR membrane treatment tank used in this application is an existing device.

[0073] The sludge produced in the flotation area of ​​the flocculation flotation tank and the O-level biological tank is lifted to the sludge tank for room temperature digestion. The supernatant of the sludge tank is returned to the A-level oxidation tank for reprocessing. The residual amount of sludge after digestion is reduced, and the digested residue is cleaned regularly, generally once every six months. The cleaning method can be to use a fecal suction truck to extend into the bottom of the sludge from the inspection hole of the sludge tank to suck and transport it out.

[0074] Preferably, the flocculation flotation tank comprises: a dosing area and an air flotation area 11; the dosing area is arranged on one side of the air flotation area 11 and is connected to the air flotation area 11;

[0075] The dosing area includes: a multi-stage overflow area and a liquid outlet area 23; a dosing group pipe and a main water inlet pipe 212 are arranged on the liquid inlet end of the overflow area; a second overflow plate 222 is arranged on the liquid outlet end of the overflow area, and the top surface of the second overflow plate 222 is connected to the liquid outlet area 23; a water outlet 233 is arranged on the side wall of the bottom surface of the liquid outlet area 23, and the water outlet 233 connects the liquid outlet area 23 and the air flotation area 11;

[0076] The flotation area 11 includes: multiple gas adding pipes 242 and a ventilation plate 251; one end of the gas adding pipe 242 is connected to the compressed air machine; the other end extends into the flotation area 11 and is arranged near the dosing area; the ventilation plate 251 is arranged on the extending end of the gas adding pipe 242; the ventilation plate 251 includes: a plate body and an air outlet main pipe 253; one end of the air outlet main pipe 253 is arranged perpendicular to the side wall of the plate body, and the other end is arranged to extend outward perpendicular to the side wall of the plate body; an end cover 254 is arranged on the extending end of the air outlet main pipe 253, and a plurality of air outlet micropores 255 are provided on the end cover 254.

[0077] The device can utilize the flow rate of the pumped wastewater to achieve mixing and stirring of the sewage and the reagent at the liquid inlet end of the overflow zone, and can achieve uniform mixing of the reagent without setting up an additional stirring device. At the same time, through multi-stage overflow, the flocculants such as alum flowers formed after the addition of the drug are initially settled and filtered, which is beneficial to improve the quality of the final treated water body and reduce the content of suspended matter in the treated water, so as to meet the Class A standard in the "Pollutant Discharge Standard for Urban Wastewater Treatment Plants" GB18918-2002.

[0078] By ventilating through multiple ventilation disks 251 arranged in the flotation area 11, it is possible to avoid excessive bubbling volume caused by air flow fluctuations, effectively obtain a large number of small-volume bubbles, improve ventilation stability, achieve effective adsorption and flotation of flocculants contained in sewage, and achieve effective separation of flocculants and water bodies.

[0079] When in use, the dosing group pipe and the main water inlet pipe 212 are opened to introduce the agent and the sewage to be treated into the overflow area. The sewage to be treated comes from the pH value adjustment tank and is pumped with a high flow rate. After impacting the liquid inlet end of the overflow area and mixing evenly with the agent, it overflows from the multi-stage overflow area into the liquid outlet area 23 and then discharges. The sewage discharged enters the flotation area 11. When the liquid level exceeds the air inlet pipe, ventilation is turned on. After the gas enters the sewage to generate a large number of small bubbles, the bubbles float up and carry the alum flowers out of the water body.

[0080] Preferably, the multi-stage overflow area includes: a first overflow area 20, a second overflow area 22, and a liquid outlet area 23; a dosing group pipe and a main water inlet pipe 212 are inserted on the top surface of the first overflow area 20; a first overflow plate 215 is inserted between the first overflow area 20 and the second overflow area 22; the second overflow area 22 is arranged below the first overflow area 20; the top surface of the first overflow plate 215 is arranged below the center line of the side wall of the first overflow area 20; the liquid outlet area 23 is arranged on the other side of the second overflow area 22, and the top surface of the liquid outlet area 23 is arranged below the center line of the second overflow area 22; a second overflow plate 222 is inserted on the side wall of the liquid outlet area 23 and the second overflow area 22;

[0081] A water outlet 233 is provided at the lower part of the side wall adjacent to the liquid outlet area 23 and the air flotation area 11 ; the air flotation area 11 is connected to the liquid outlet area 23 through the water outlet 233 .

[0082] By setting up two-stage overflow, the liquid inlet flow rate can be reduced, the water flow rate can be retained in a smaller range, stirring and mixing can be achieved, and at the same time, the height difference overflow can be used to utilize gravity sedimentation to achieve effective separation of alum flocs.

[0083] Preferably, the first overflow area 20 includes: an inclined plate 214; the inclined plate 214 is obliquely arranged on the bottom surface of the first overflow area 20 at an angle of 25-35° to the horizontal plane. The inclined plate 214 can limit the floating of suspended matter and increase the sedimentation rate, which has a better sedimentation effect on water bodies with faster flow rates.

[0084] Preferably, the top surface of the first overflow plate 215 is higher than the top surface of the second overflow plate 222 .

[0085] Preferably, the second overflow area 22 includes: a baffle 221; the baffle 221 is accommodated in the second overflow area 22 and spaced from the bottom surface of the second overflow area 22. This arrangement can increase the sedimentation rate of the second overflow area 22, settle and separate large-volume suspended matter, and prevent the suspended matter from floating up into the overflow water body.

[0086] Preferably, the liquid outlet area 23 comprises: a plurality of flow blocking strips 231; the flow blocking strips 231 are arranged at intervals along the liquid outlet area 23; a plurality of inverted hooks are arranged on the outer wall of the flow blocking strips 231, and the tips of the inverted hooks are arranged toward the inner wall of the liquid outlet area 23. According to this arrangement, after the alum flocs contained in the outflowing liquid are hooked, after the flocs are formed and accumulated on the side wall of the flow blocking strips 231, the flocs contained in the flowing water are enriched by the flocs, thereby reducing the content of suspended matter in the liquid entering the flotation area 11.

[0087] Preferably, the vent plate 251 includes: a plurality of outlet branch pipes 252; one end of the outlet branch pipes 252 is connected to the plate body and extends upward perpendicular to the plate body; and a plurality of outlet micropores 255 are provided on the extended end of the outlet branch pipes 252.

[0088] According to this setting, the gas can be discharged toward the top surface, and the flocculants attached to the gas outlet micropores 255 can be blown away in time to prevent the gas outlet from being blocked; at the same time, small bubbles are continuously obtained to achieve effective adsorption of the flocculants.

[0089] Preferably, it includes: multiple voltage-stabilizing tubes, which are connected to adjacent gas-filling tubes 242; according to this arrangement, the connected voltage-stabilizing tubes can be used to achieve airflow connection between the gas-filling tubes 242, thereby maintaining a stable air pressure in the tube, which is beneficial to avoid the generation of large bubbles, improve the operating stability of the flotation zone 11, increase the adsorption and floating rate of flocculants, and reduce the content of suspended matter in the treated water.

[0090] Preferably, the gas supply pipe 242 includes: a first pipe, a second pipe, and a third pipe; the voltage regulator pipe includes: a first voltage regulator pipe 245 and a second voltage regulator pipe 246; the first voltage regulator pipe 245 is arranged between the adjacent first pipe and the second pipe, and is connected to the first pipe and the second pipe; the second voltage regulator pipe 246 is arranged between the adjacent second pipe and the third pipe, and is connected to the second pipe and the third pipe; the first voltage regulator pipe 245 is arranged above the second voltage regulator pipe 246. According to this arrangement, the air pressure near the air inlet end can be diffused evenly between the adjacent gas supply pipes 242 as soon as possible through the voltage regulator pipe, so as to avoid excessive pressure impacting the air outlet plate near the air inlet end.

[0091] In a specific implementation, the air outlet branch pipe 252 may not be provided.

[0092] In a specific embodiment, it includes: a first mounting plate 21, a first dosing pipe 211, and a second dosing pipe 213; the first mounting plate 21 is mounted on the top surface of one side of the first overflow area 20; the first dosing pipe 211 and the second dosing pipe 213 are inserted on the first mounting plate 21 at intervals, and are symmetrically arranged on both sides of the main water inlet pipe 212. This arrangement can improve the mixing uniformity of the agent in the sewage.

[0093] In a specific embodiment, it includes: a second mounting plate 24, on which the first tube, the second tube, and the third tube are installed at intervals; the second mounting plate 24 is arranged on the inner side wall of the air flotation area 11 close to the dosing area. This arrangement can improve the uniformity of air intake. Example

[0094] In the following examples, all materials and instruments used are commercially available unless otherwise specified.

[0095] The above system is used to treat the wastewater listed in Table 2 below. The wastewater is the wastewater generated by the normal production of Yunnan Simao Beigui Coffee Co., Ltd. The daily amount of wastewater is 50-80m 3 , and conduct random inspections on the generated sewage. The detection methods of various indicators of the treated sewage are listed in Table 1.

[0096] Table 1

[0097]

[0098] Table 2 (Unit: mg / L)

[0099]

[0100] The above coffee primary processing wastewater is treated by the above system according to the following operations:

[0101] 1) After the wet primary processing coffee fruit wastewater flows through the filter screen set on the top surface of the primary filter tank, it enters the pH adjustment tank and is neutralized with lime water to a pH value of 6-9; the neutralized wastewater enters the dosing area of ​​the flocculation flotation tank and is mixed with coagulants and flocculants before entering the flotation area; after pressurized air is introduced into the flotation area through the air inlet pipe, the gas flows out from the bubbling nozzle set on the bottom surface of the air inlet pipe and floats to the liquid surface to form scum; the automatic chain scum plate scrapes the scum onto the filter screen at one end of the flotation area, and the scum is discharged regularly after filtering; the use of a 5-15 mesh filter can effectively filter solid impurities with a particle size exceeding 5 mesh, and the filter screen is an open structure, which is convenient for regular cleaning.

[0102] The test results of the effluent at each stage after treatment by the above system are shown in Table 3 below;

[0103] Table 3

[0104]

[0105] After the wastewater is treated by the above system, clean water is discharged from the discharge port, and sampling and testing are carried out at the discharge port. The testing method is based on the testing method in the "Pollutant Emission Standard for Urban Wastewater Treatment Plants" (GB18918-2002). The results are shown in Table 4 below.

[0106] Table 4

[0107]

[0108] The water quality of the sampled water after treatment meets the Class A standard in the Pollutant Discharge Standard for Urban Wastewater Treatment Plants (GB18918-2002) and meets the discharge standard. The sludge generated during the wastewater treatment process is regularly pumped out by a fecal suction truck, with a cycle of 3 to 4 months.

[0109] As can be seen from the above, the sewage treatment system provided by the present application can effectively treat the sewage generated by the primary processing of coffee berries and meet the discharge standards. The treatment capacity can meet the production capacity requirements during the peak season.

[0110] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A wet primary processing coffee fruit wastewater treatment system, characterized in that: include: Pre-filtration tank, pH adjustment tank, flocculation flotation tank, neutralization tank, biochemical treatment integrated device, MBR membrane treatment tank; The primary filter tank is connected to the liquid inlet pipeline of the pH value adjustment tank; the liquid outlet of the pH value adjustment tank is connected to the liquid inlet pipeline of the dosing area of ​​the flocculation flotation tank; the liquid outlet of the dosing area of ​​the flocculation flotation tank is connected to the pipeline of the flotation area; an aeration pipe is inserted in the flotation area; a liquid outlet is set at the lower part of the flotation area and is connected to the liquid inlet of the neutralization tank pipe; an aeration pipe is inserted inside the neutralization tank; the liquid outlet of the neutralization tank is connected to the liquid inlet pipeline of the biochemical treatment integrated device; The biochemical treatment integrated device is connected to the liquid inlet pipeline of the MBR membrane treatment tank; a filter screen is arranged on the top surface of the primary filter tank; The wastewater in the pH adjustment tank is neutralized with lime water until the pH value of the effluent is 6-9; The dosing area is provided with dosing pipes in pairs, and the dosing pipes are used to introduce flocculants and coagulants respectively. The filter mesh size is 5 to 15 meshes; The pH value of the wastewater from wet primary processing of coffee berries is greater than 3.8, the suspended solids content is less than 300 mg / L, the chromaticity is less than 200, the chemical oxygen demand CODcr is less than 16000 mg / L, the five-day biochemical oxygen demand BOD5 is less than 4000 mg / L, the total nitrogen content is less than 100 mg / L, the total phosphorus is less than 13 mg / L, and the ammonia nitrogen content is less than 50 mg / L; The flocculation flotation tank comprises: a dosing zone and an air flotation zone (11); the dosing zone is arranged on one side of the air flotation zone (11) and is connected to the air flotation zone (11); The dosing area comprises: a multi-stage overflow area and a liquid outlet area (23); a dosing group pipe and a main water inlet pipe (212) are arranged on the liquid inlet end of the overflow area; a second overflow plate (222) is arranged on the liquid outlet end of the overflow area, and the top surface of the second overflow plate (222) is connected to the liquid outlet area (23); a water outlet (233) is provided on the side wall of the bottom surface of the liquid outlet area (23), and the water outlet (233) is connected to the liquid outlet area (23) and the air flotation area (11); The flotation zone (11) comprises: a plurality of gas-adding pipes (242) and a vent plate (251); one end of the gas-adding pipe (242) is connected to a compressed air machine; the other end extends into the flotation zone (11) and is arranged close to the dosing zone; the vent plate (251) is arranged on the extending end of the gas-adding pipe (242); the vent plate (251) comprises: a plate body and an air outlet main pipe (253); one end of the air outlet main pipe (253) is arranged perpendicular to the side wall of the plate body, and the other end is arranged perpendicular to the side wall of the plate body and extends outward; an end cover (254) is arranged on the extending end of the air outlet main pipe (253), and a plurality of air outlet micro holes (255) are provided on the end cover (254).

2. The wet primary processing coffee fruit wastewater treatment system according to claim 1, characterized in that: The multi-level overflow area comprises: a first overflow area (20), a second overflow area (22), and a liquid outlet area (23); a dosing group pipe and a main water inlet pipe (212) are inserted on the top surface of the first overflow area (20); a first overflow plate (215) is inserted between the first overflow area (20) and the second overflow area (22); the second overflow area (22) is arranged below the first overflow area (20); the top surface of the first overflow plate (215) is arranged below the center line of the side wall of the first overflow area (20); the liquid outlet area (23) is arranged on the other side of the second overflow area (22), and the top surface of the liquid outlet area (23) is arranged below the center line of the second overflow area (22); a second overflow plate (222) is inserted on the side wall where the liquid outlet area (23) and the second overflow area (22) meet; A water outlet (233) is provided at the lower part of the side wall of the liquid outlet area (23) adjacent to the air flotation area (11); the air flotation area (11) and the liquid outlet area (23) are connected via the water outlet (233).

3. The wet primary processing coffee fruit wastewater treatment system according to claim 2, characterized in that: The first overflow area (20) comprises an inclined plate (214); the inclined plate (214) is obliquely arranged on the bottom surface of the first overflow area (20) at an angle of 25 to 35 degrees to the horizontal plane.

4. The wet primary processing coffee fruit wastewater treatment system according to claim 2, characterized in that: The top surface of the first overflow plate (215) is higher than the top surface of the second overflow plate (222).

5. The wet primary processing coffee cherry wastewater treatment system according to claim 2, characterized in that: The second overflow area (22) comprises: a baffle plate (221); the baffle plate (221) is accommodated in the second overflow area (22) and is spaced apart from the bottom surface of the second overflow area (22).

6. The wet primary processing coffee cherry wastewater treatment system according to claim 1, characterized in that: The liquid outlet area (23) comprises: a plurality of flow blocking strips (231); the flow blocking strips (231) are arranged at intervals along the liquid outlet area (23) in a transverse direction; and a plurality of inverted hooks are arranged on the outer side walls of the flow blocking strips (231), with the tips of the inverted hooks facing the inner side wall of the liquid outlet area (23).

7. The wet primary processing coffee cherry wastewater treatment system according to claim 1, characterized in that: The vent plate (251) comprises: a plurality of air outlet branch pipes (252); one end of the air outlet branch pipe (252) is connected to the plate body and extends vertically upward from the plate body; and a plurality of air outlet micro holes (255) are arranged on the extended end of the air outlet branch pipe (252).

8. The wet primary processing coffee cherry wastewater treatment system according to claim 1, characterized in that: The ventilation plate (251) comprises: a plurality of voltage-stabilizing tubes, the voltage-stabilizing tubes being connected to adjacent gas supply tubes (242); The gas filling pipe (242) comprises: a first pipe, a second pipe, and a third pipe; the voltage-stabilizing pipe comprises: a first voltage-stabilizing pipe (245) and a second voltage-stabilizing pipe (246); the first voltage-stabilizing pipe (245) is arranged between the adjacent first pipe and the second pipe, and is in communication with the first pipe and the second pipe; the second voltage-stabilizing pipe (246) is arranged between the adjacent second pipe and the third pipe, and is in communication with the second pipe and the third pipe; the first voltage-stabilizing pipe (245) is arranged above the second voltage-stabilizing pipe (246).

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