CN116177791A - Large-scale pig farm liquid manure advanced treatment technology - Google Patents

Abstract

The invention discloses a large-scale pig farm liquid manure advanced treatment technology, and relates to the technical field of manure treatment. The invention comprises the following steps: step one: the pretreatment process comprises the following steps: filtering, solid-liquid separating and precipitating liquid manure generated in a pig farm to remove solid components in liquid pollutants; step two: anaerobic process: degrading COD concentration in the liquid manure, separating gas, water and mud generated in the degradation process, discharging effluent in an overflow mode, and collecting methane. The invention provides a large-scale pig farm liquid manure advanced treatment technology, which comprises a pretreatment unit, an anaerobic process, an aerobic process, an advanced treatment process and a sludge treatment process; after the liquid manure in the large-scale pig farm is subjected to advanced treatment, the matched use pressure of the consumed land in the operation period of the pig farm can be effectively reduced, the concentration of pollutants can be reduced to a lower level, and secondary pollution caused by overhigh concentration of the pollutants is prevented.

Description

Large-scale pig farm liquid manure advanced treatment technology

Technical Field

The invention belongs to the technical field of fecal sewage treatment, and particularly relates to a large-scale liquid fecal sewage advanced treatment technology for a pig farm.

Background

Along with the adjustment of rural industry economy, the development of a large-scale pig farm is strongly promoted in various regions of the country in recent years, and pig breeding is gradually carried out in large scale and intensive, so that the environmental protection problem generated by the pig farm is increasingly outstanding, and meanwhile, a large amount of liquid pollutants are generated when the large-scale pig farm is rising, and if the liquid pollutants are directly discharged, serious pollution of surrounding environment is seriously caused, and the sustainable development of the agricultural industry is greatly influenced, so that the pollutant disposal of the large-scale pig farm is very important.

The present invention has been made in view of this.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects of the prior art and providing a large-scale pig farm liquid manure advanced treatment technology.

In order to solve the technical problems, the invention adopts the basic conception of the technical scheme that:

a large-scale pig farm liquid manure advanced treatment technology comprises the following steps:

step one: the pretreatment process comprises the following steps: filtering, solid-liquid separating and precipitating liquid manure generated in a pig farm to remove solid components in liquid pollutants; wherein, the manure is filtered, solid-liquid separation and precipitation are respectively processed by a mechanical grid, a solid-liquid separator and a primary sedimentation tank; the method comprises the steps of rapidly degrading COD concentration in liquid manure through anaerobic fermentation, separating gas, water and mud generated in the anaerobic fermentation process through a three-phase separator, and collecting methane through a collector; the mechanical grating is of an automatic lifting type, the solid-liquid separator is of a spiral extrusion type, raw water enters equipment to carry out solid-liquid separation through a fine screen, suspended matters in the raw water are intercepted, gravity slides down into a spiral extrusion unit, the suspended matters are dehydrated through spiral extrusion, solid-liquid separation is achieved, the solid-liquid separator is required to be made of stainless steel materials, and strong corrosion resistance is required;

step two: anaerobic process: degrading COD concentration in the liquid manure, separating gas, water and mud generated in the degradation process, discharging effluent in an overflow mode, and collecting methane; using a UASB anaerobic reactor to rapidly degrade COD concentration in the liquid manure by anaerobic fermentation, wherein the anaerobic residence time is 4-5d;

step three: and (3) an aerobic treatment process: oxidizing free nitrogen such as ammonia nitrogen in the liquid into nitrogen, adopting an endogenous carbon supplementing mode, reducing an external carbon source, reducing operation cost and removing organic matters; the primary sedimentation tank in the secondary A/O process adopts a biological contact oxidation process, and a combined filler is arranged to form a biological film, so that difficult degradation organic matters are removed; the aerobic process section is in a two-stage A/O process mode, suspended pollutants such as carbohydrate and soluble organic matters in sewage are hydrolyzed into organic acids by heterotrophic bacteria in an anoxic section (A section) in the A/O process, macromolecular organic matters are decomposed into small molecular organic matters, insoluble organic matters are converted into soluble organic matters, compounds such as proteins are ammoniated and dissociated to form ammonia by the heterotrophic bacteria in the aerobic section (O section), NH3-N is oxidized into NO 3-by the nitrification of autotrophic bacteria under the aerobic condition, the NO 3-is reduced into molecular nitrogen (N2) by the denitrification of the heterotrophic bacteria under the anoxic condition, and the hydraulic retention time of the first-stage A/O section is 4-5d;

step four: the deep treatment process comprises the following steps: deeply treating the excrement by a coagulating sedimentation mode, and simultaneously adding a medicament for decoloring to reduce the chromaticity of the discharged water; coagulating sedimentation is carried out by adding a mixture of PAC and PAM;

step five: the sludge treatment process comprises the following steps: the sludge is collected in a centralized way by a sludge pond, dried by a sludge dehydrator and transported to a sludge treatment plant for treatment; wherein, the sludge dehydrator adopts a spiral shell stacking dehydrator; the stacked spiral sludge dewatering machine is matched with an automatic cleaning device, and 304 stainless steel materials are selected, so that corrosion prevention is facilitated.

After the technical scheme is adopted, compared with the prior art, the invention has the following beneficial effects, and of course, any product for implementing the invention does not necessarily need to achieve all the following advantages at the same time:

the invention provides a large-scale pig farm liquid manure advanced treatment technology, which comprises a pretreatment unit, an anaerobic process, an aerobic process, an advanced treatment process and a sludge treatment process. After the liquid manure in the large-scale pig farm is subjected to advanced treatment, the matched use pressure of the consumed land in the operation period of the pig farm can be effectively reduced, the concentration of pollutants can be reduced to a lower level, and secondary pollution caused by overhigh concentration of the pollutants is prevented.

The following describes the embodiments of the present invention in further detail with reference to the accompanying drawings.

Drawings

The drawings in the following description are only examples of embodiments from which other drawings may be derived by those skilled in the art without the exercise of inventive faculty. Attached at

In the figure:

FIG. 1 is a schematic flow chart of a processing technique according to an embodiment of the invention.

It should be noted that these drawings and the written description are not intended to limit the scope of the inventive concept in any way, but to illustrate the inventive concept to those skilled in the art by referring to the specific embodiments.

Detailed Description

The invention will now be described in further detail with reference to the accompanying drawings.

Referring to fig. 1, in this embodiment, a technology for advanced treatment of liquid manure in a large-scale pig farm is provided, which includes the following steps:

step one: the pretreatment process comprises the following steps: liquid manure generated in a pig farm is subjected to solid-liquid separation through a mechanical grid filter and a solid-liquid separator, then is precipitated through a primary sedimentation tank, and finally is subjected to an air floatation process treatment method, so that solid components in liquid pollutants are effectively removed;

step two: anaerobic process: the liquid after the pretreatment unit is lifted to an anaerobic treatment process section mainly comprising UASB through a delivery pump, COD concentration in liquid manure is rapidly degraded through anaerobic fermentation, the anaerobic section is matched with a corresponding three-phase separator, gas, water and mud generated in the anaerobic fermentation process can be separated, effluent is discharged in an overflow mode, and biogas is uniformly collected through a collector;

step three: and (3) an aerobic treatment process: lifting liquid generated in the anaerobic section to an aerobic process section through a conveying pump for biochemical treatment, wherein a main process of the aerobic unit adopts a two-stage A/O process mode to form a multi-stage nitrification and denitrification mode, and free nitrogen such as ammonia nitrogen in the liquid is rapidly oxidized into nitrogen; meanwhile, by adopting a process design and an endogenous carbon supplementing mode, the additional carbon source is reduced, and the running cost is reduced; the primary sedimentation tank in the secondary A/O process adopts a biological contact oxidation process, and a combined filler is arranged to form a biological film, so that the removal of refractory organic matters is facilitated;

step four: the deep treatment process comprises the following steps: lifting the liquid generated in the aerobic section to a coagulating sedimentation tank through a conveying pump, and finally achieving the effect of advanced treatment in a coagulating sedimentation mode; meanwhile, the addition of the later-stage medicament can also play a role in decoloring, so that the chromaticity of the discharged water is reduced;

step five: the sludge treatment process comprises the following steps: the sludge generated in the system operation process is uniformly concentrated into a sludge pool, dried by a sludge dehydrator and then transported to a qualified sludge treatment plant for treatment; the sludge dewatering machine adopts the spiral shell overlapping dewatering machine, is simple to operate, has high automation degree, can realize 24-hour unmanned operation, and greatly saves the labor intensity of operators.

The application of one aspect of the embodiment is: firstly, liquid manure generated in a pig farm is pretreated, large-particle solids such as pig hair, garbage bags and the like in the liquid manure are separated from liquid by filtering raw water through a mechanical grid, then suspended solids in the sewage are intercepted through a solid-liquid separator, the solids slide down into a screw extrusion unit through gravity, the suspended solids are dehydrated through screw extrusion, the liquid is subjected to precipitation treatment through a primary sedimentation tank, solid components in the liquid contaminant can be effectively removed through the mechanical grid and solid-liquid separation, meanwhile, COD (chemical oxygen demand) in the liquid is removed by 20-25%, SS (suspended solids) removal rate is 65-70%, ammonia nitrogen is removed by 5-8%, and total phosphorus is removed by 0%. The precipitated liquid is subjected to air floatation process equipment again to remove suspended matters, so that the COD concentration in the liquid after solid-liquid separation is removed by 20% -25%, SS is removed by 65% -70%, ammonia nitrogen is removed by 5% -6%, and total phosphorus can be removed by 40% -45%. The pretreated liquid is pumped into a UASB anaerobic reactor through a delivery pump for anaerobic fermentation, the water distribution system of the anaerobic section adopts rotary-cut water inflow at the bottom, the liquid enters tangentially from the bottom of the reactor, the sludge at the bottom can be stirred, the sewage and the granular sludge are fully mixed, the treatment efficiency is improved, the anaerobic residence time is 4-5d, COD is removed by 60-65%, SS is removed by 15-20%, ammonia nitrogen is removed by 0%, and total phosphorus can be removed by about 5%. Anaerobic effluent is discharged to a sedimentation tank in an overflow mode, and then is pumped into an aerobic process section through a conveying pump, the aerobic process is mainly in a two-stage A/O process mode, an anoxic section (A section) and an aerobic section (O section) in the A/O process are connected in series, suspended pollutants such as carbohydrates and soluble organic matters in sewage are hydrolyzed into organic acids by heterotrophic bacteria in the anoxic section (A section), the macromolecular organic matters are decomposed into small molecular organic matters, the insoluble organic matters are converted into soluble organic matters, the heterotrophic bacteria in the aerobic section (O section) carry out ammoniation on compounds such as proteins and the like to remove ammonia, the nitrifying action of autotrophic bacteria in the aerobic section (O section) oxidizes NH3-N into NO3-, then the sewage in the aerobic section (O section) is returned to the anoxic section (A section) through reflux control, the denitrifying action of the heterotrophic bacteria in the anoxic condition reduces NO 3-into molecular nitrogen (N2), the hydraulic retention time of the first-stage A/O section is 4-5d, COD removal 75% -80%, SS removal is about 75% -80%, total removal of nitrogen and total ammonia nitrogen and total removal time of 75% -50% -75% of nitrogen and total ammonia nitrogen and total removal is about 75% -50%. The sewage generated in the aerobic section is subjected to advanced treatment again through coagulating sedimentation, the advanced treatment is completed by adding a mixture of PAC (solution concentration is 10%) and PAM (solution concentration is 3%o), the pollutant index concentration and the effluent chromaticity are further reduced, the COD is removed by 15-20%, the SS is removed by 15-20%, the ammonia nitrogen is removed by 40-50%, and the total phosphorus can be removed by about 50-55%. And finally, after the produced sewage meets the farmland irrigation index and the livestock and poultry pollutant discharge index, irrigating and absorbing. The sludge generated in the whole sewage treatment process is subjected to powerful dehydration by adopting a spiral-pile type sludge dehydrator, the water content of the sludge is controlled to be 60% -70%, and then the sludge is transported to a qualified third party for treatment.

The mechanical grating in the first step of the embodiment is an automatic lifting type, so that large-particle solid matters such as pig hair, garbage bags and the like in the liquid can be removed rapidly and effectively. The solid-liquid separation machine is of a spiral extrusion type, raw water enters equipment to carry out solid-liquid separation through a fine screen, suspended matters in the raw water are intercepted, gravity slides downwards into a spiral extrusion unit, the suspended matters are dehydrated through spiral extrusion, solid-liquid separation is achieved, the solid-liquid separation machine is made of stainless steel materials, and strong corrosion resistance is required. Through a mechanical grid and a solid-liquid separation mode, COD in the liquid can be removed by 20-25%, SS (suspended solid) removal rate is 65-70%, ammonia nitrogen is removed by 5-8%, and total phosphorus is removed by 0%. The air floatation process mainly depends on a gas dissolving system in the process to generate a large number of tiny bubbles in the culture sewage, and the tiny bubbles which are highly dispersed can be effectively attached to suspended matter particles, so that the density of the particles becomes smaller than that of water, and the particles float on the water surface by utilizing the buoyancy principle, thereby rapidly realizing solid-liquid separation of the sewage. The air floatation device is matched with an independent and efficient air dissolution system, the particle size of air bubbles can be reduced to be below 60 microns, so that the air bubbles and particles in sewage can be effectively combined together, the whole air floatation process can enable the concentration of COD in liquid to be removed by 20% -25%, SS to be removed by 65% -70%, ammonia nitrogen to be removed by 5% -6% and total phosphorus to be removed by 40% -45% after solid-liquid separation.

In the UASB anaerobic reactor in the step two of the embodiment, the anaerobic residence time is 3-4d, the COD is removed by 60% -65%, the SS is removed by 15% -20%, the ammonia nitrogen is removed by 0%, and the total phosphorus can be removed by about 5%. The anaerobic section water distribution system adopts rotary-cut water inflow at the bottom, liquid enters tangentially from the bottom of the reactor, and can stir bottom sludge, so that sewage and granular sludge are fully mixed, the treatment efficiency is improved, and meanwhile, the water distribution system can be prevented from being blocked; the three-phase separator ensures that gas, water and mud can be effectively separated according to PP materials or carbon steel anti-corrosion materials; a heating device is arranged in the anaerobic tank to maintain the optimal temperature required by the anaerobic reaction. The UASB anaerobic reactor is used for treating pig farm sewage, the concentration of sludge in the reactor is high, the average concentration of sludge can reach 25-35gVSS/L, the removal efficiency of the reactor can be effectively improved, meanwhile, the organic load of the reactor is higher, the hydraulic retention time can be effectively shortened to 3-4d, and the volume load can reach 5-7kgCOD/m < 3 >/d when medium-temperature fermentation is adopted. The whole UASB anaerobic reactor is not added with mixing and stirring facilities, methane generated in the whole process depends on the fermentation process as an energy source, the sludge on the upper part of the sludge bed can be in a suspension state in the methane rising process, the lower part of the sludge bed is also provided with a certain degree of boosting and stirring effects, the whole anaerobic sludge bed is not provided with a sludge carrier, the investment cost can be effectively saved, and meanwhile, the problem of water inlet blockage caused by adding carrier fillers to the sludge bed can be prevented. The reactor is internally provided with a three-phase separator, and the sludge separated by the precipitation zone can be returned to the sludge bed reaction zone again.

The aerobic process section in the third step of the embodiment is a two-stage A/O process mode, suspended pollutants such as carbohydrate and soluble organic matters in sewage are hydrolyzed into organic acids by anoxic section (section A) heterotrophic bacteria in the A/O process, macromolecular organic matters are decomposed into micromolecular organic matters, insoluble organic matters are converted into soluble organic matters, the compounds such as proteins are ammoniated by the aerobic section (section O) heterotrophic bacteria to release ammonia, NH3-N is oxidized into NO 3-by nitrification of autotrophic bacteria under aerobic condition, the NO 3-is returned to anoxic section (section A) by reflux control, the denitrification of the heterotrophic bacteria reduces NO 3-into molecular nitrogen (N2) under anoxic condition, the hydraulic retention time of the first-stage A/O section is 4-5d, COD is removed by 75-80%, ammonia nitrogen is removed by 70-75%, total phosphorus can be removed by about 50-55%, the hydraulic retention time of the second-stage A/O section is 2-3d, COD is removed by 65-70%, and the total phosphorus can be removed by about 45-50%. The whole A/O reaction tank aerobic section adopts a biological contact oxidation process, biological filler is arranged in the tank body, an adhesion bed is provided for aerobic biological strains, the concentration of microorganisms in the tank body is rapidly increased, and the treatment efficiency is effectively improved; meanwhile, the filler can play a role in cutting bubbles, so that the oxygen transfer efficiency is improved. When the sewage in pig farm is treated, the underwater aeration device is made of ABS resin material, the aerator is made of high-quality rubber and ABS material, the corrosion resistance is strong, and sufficient defoaming facilities are needed to be added in the aeration stage, so that the aerobic sludge is taken away while the overflow of bubbles is prevented. The biological filler is fixed by adopting a carbon steel anti-corrosion bracket.

In the advanced treatment process in the step four of the embodiment, the coagulating sedimentation is performed by adding a mixture of PAC and PAM, so that the pollutant index concentration and the effluent chromaticity are further reduced, the concentration of PAC solution is 10%, the concentration of PAM solution is 3 per mill, PAC is polyaluminum chloride, PAM is polyacrylamide, COD is removed by 15-20%, SS is removed by 15-20%, ammonia nitrogen is removed by 40-50%, and total phosphorus can be removed by about 50-55%.

In the fifth step of the sludge treatment process of the embodiment, the stacked spiral sludge dewatering machine is adopted, the automatic cleaning device is matched, and 304 stainless steel materials are selected, so that corrosion prevention is facilitated. The water content of the sludge is 60-70%.

The present invention is not limited to the above embodiments, and any person who can learn the structural changes made under the teaching of the present invention can fall within the scope of the present invention if the present invention has the same or similar technical solutions. The technology, shape, and construction parts of the present invention, which are not described in detail, are known in the art.

Claims (10)

1. The large-scale pig farm liquid manure advanced treatment technology is characterized by comprising the following steps of:

step one: the pretreatment process comprises the following steps: filtering, solid-liquid separating and precipitating liquid manure generated in a pig farm to remove solid components in liquid pollutants;

step two: anaerobic process: degrading COD concentration in the liquid manure, separating gas, water and mud generated in the degradation process, discharging effluent in an overflow mode, and collecting methane;

step three: and (3) an aerobic treatment process: oxidizing free nitrogen such as ammonia nitrogen in the liquid into nitrogen, adopting an endogenous carbon supplementing mode, reducing an external carbon source, reducing operation cost and removing organic matters;

step four: the deep treatment process comprises the following steps: deeply treating the excrement by a coagulating sedimentation mode, and simultaneously adding a medicament for decoloring to reduce the chromaticity of the discharged water;

step five: the sludge treatment process comprises the following steps: the sludge is collected in a centralized way by the sludge pond, dried by the sludge dehydrator and transported to a sludge treatment plant for treatment.

2. The large-scale pig farm liquid manure deep treatment technology according to claim 1, wherein in the first step, manure filtration, solid-liquid separation and sedimentation are respectively carried out by adopting a mechanical grid, a solid-liquid separator and a primary sedimentation tank.

3. The large-scale pig farm liquid manure deep treatment technology according to claim 1, wherein in the second step, the COD concentration in the liquid manure is rapidly degraded by anaerobic fermentation, gas, water and mud generated in the anaerobic fermentation process are separated by a three-phase separator, and biogas is collected by a collector.

4. The large-scale pig farm liquid manure advanced treatment technology according to claim 1, wherein in the third step, a two-stage A/O process mode is adopted to form a multi-stage nitrification and denitrification mode, free nitrogen such as ammonia nitrogen in liquid is rapidly oxidized into nitrogen, meanwhile, an endogenous carbon supplementing mode is adopted, an external carbon source is reduced, the operation cost is reduced, a biological contact oxidation process is adopted in a primary sedimentation tank in a secondary A/O process, and a combined filler is arranged to form a biological film, so that the removal of refractory organic matters is facilitated.

5. The large-scale pig farm liquid manure deep treatment technology according to claim 1, wherein in the fifth step, the sludge dewatering machine is a spiral shell stacking dewatering machine.

6. The large-scale pig farm liquid manure advanced treatment technology according to claim 1, wherein in the first step, the mechanical grating is automatically lifted, the solid-liquid separator is spiral extrusion type, raw water enters the equipment to carry out solid-liquid separation through a fine screen, suspended matters in the raw water are trapped, gravity slides down into a spiral extrusion unit, the suspended matters are dehydrated through spiral extrusion, solid-liquid separation is realized, the solid-liquid separator is made of stainless steel materials, and strong corrosion resistance is required.

7. The large-scale pig farm liquid manure advanced treatment technology according to claim 1, wherein in the second step, a UASB anaerobic reactor is used to rapidly degrade the COD concentration in the liquid manure by anaerobic fermentation, and the anaerobic residence time is 4-5d.

8. The advanced treatment technology for liquid manure in a large-scale pig farm according to claim 1, wherein in the third step, the aerobic process section is in a two-stage A/O process mode, suspended pollutants such as carbohydrate and soluble organic matters in sewage are hydrolyzed into organic acids by heterotrophic bacteria in the A/O process, the macromolecular organic matters are decomposed into small molecular organic matters, the insoluble organic matters are converted into soluble organic matters, the heterotrophic bacteria in the aerobic section (O section) ammonify the protein and other compounds to release ammonia, the autotrophic bacteria nitrify NH3-N to form NO 3-under aerobic conditions, the NO 3-is reduced into molecular nitrogen (N2) by denitrification of the heterotrophic bacteria under the anaerobic conditions, and the hydraulic retention time of the first-stage A/O section is 4-5d.

9. A large scale pig farm liquid manure deep treatment technology according to claim 1, wherein in step four, the coagulation sedimentation is performed by adding a mixture of PAC and PAM.

10. The large-scale pig farm liquid manure advanced treatment technology according to claim 1, wherein in the fifth step, a stacked spiral sludge dewatering machine is adopted, an automatic cleaning device is matched, and 304 stainless steel is selected, so that corrosion prevention is facilitated.

Images