CN105084681A - Process for treating livestock slaughter wastewater - Google Patents

Abstract

The invention relates to a treatment process for livestock slaughter wastewater, which belongs to the technical field of wastewater treatment. The waste water treatment process of the present invention is realized through the following technical scheme: the waste water is firstly filtered and slag-removed through a mechanical grid, and then sequentially passed through a grease trap and a coagulation sedimentation pond for oil separation and sedimentation treatment, and then sequentially enters an anaerobic internal circulation biological fluidized bed And three-phase internal circulating biological fluidized bed for anaerobic and aerobic treatment, decompose macromolecules and refractory organic matter into inorganic matter, and finally carry out sedimentation treatment, the sludge enters the sludge tank, and the upper clear water is discharged after being treated up to the standard. The invention adopts the anaerobic internal circulation biological fluidized bed and the three-phase internal circulation biological fluidized bed to jointly treat the slaughter wastewater, and has the characteristics of environmental protection, high efficiency, low cost, strong operation flexibility and the like. The wastewater treatment process is simple, stable, and has a large processing capacity, and it is easy to realize integration, standardization, and serialization, which solves the problem that traditional treatment methods are limited by scale, capital, and technical conditions.

Description

A treatment process for livestock slaughter wastewater

technical field

The invention belongs to the technical field of environmental protection wastewater treatment, and in particular relates to livestock wastewater treatment technology, in particular to a treatment process for livestock slaughter wastewater.

Background technique

Slaughtering is a major water consumer in the meat processing industry. With the improvement of people's living standards and the increasing demand for meat products, the discharge of wastewater from slaughterhouses and meat processing plants is also increasing day by day. The wastewater produced by the livestock slaughtering and processing industry is mostly brown and has an unpleasant smell, which contains a large amount of oil, grease, hair, meat chips, bone chips, visceral debris, undigested food and feces and other solid suspensions The outflow of these sundries will cause great pollution to the environment, and even have a devastating impact, so it is necessary to establish an effective wastewater treatment method.

Slaughter wastewater is mostly high-color, high-concentration organic wastewater, which has the characteristics of high suspended solid concentration, high COD concentration, and good biodegradability. However, the high-concentration organic matter is not easy to degrade, and the treatment is difficult. Due to the impact of peak season and discontinuous production, the volume and quality of wastewater will vary greatly.

At present, the treatment of slaughter wastewater mostly adopts biological treatment processes, mainly including aerobic, anaerobic and facultative treatment methods. However, due to the high oil content of this type of wastewater and poor settling performance, it cannot achieve ideal processing effect. In addition, the scale of slaughtering enterprises is often small and the distribution is relatively scattered. Traditional treatment methods are limited by scale, capital, technology and conditions, so that advanced treatment of wastewater cannot be carried out before it is discharged, and harmful substances in it can be completely removed, causing harm to the environment. a great deal of pollution.

Contents of the invention

In order to solve the above problems, the present invention proposes a livestock slaughter wastewater treatment process with low cost, large processing capacity and good impact resistance, and provides an economical, efficient, simple operation and easy-to-implement wastewater treatment process for small and medium-sized livestock slaughter enterprises method. The present invention is achieved through the following technical solutions:

A treatment process for livestock slaughter wastewater, mainly comprising the following steps:

1) Filter the waste water through a mechanical grid to remove slag;

2) The wastewater that has been roughly treated by the grid flows into the grease trap and the coagulation sedimentation tank in turn for grease trap and sedimentation treatment;

3) The wastewater treated by oil separation precipitation enters the anaerobic internal circulation biological fluidized bed to decompose macromolecular organic matter and refractory organic matter;

4) The wastewater after anaerobic treatment enters the three-phase internal circulating biological fluidized bed for aerobic treatment, and oxidizes and decomposes the organic matter in the sewage into relatively stable inorganic matter;

5) The effluent after aerobic treatment is subjected to sedimentation treatment, the sludge enters the sludge tank, and the upper clear water is discharged after being treated up to the standard.

As a preference, the mechanical grids are in two groups, wherein the coarse grids are in front and the fine grids are in the rear, the gap between the coarse grids is 20 mm, and the gap between the fine grids is 4 mm.

As a preference, a reciprocating oil scraping device is installed on the upper part of the oil trap.

As a preference, the coagulation-sedimentation tank needs to add coagulation medicine for precipitation.

As a preference, the coagulation medicine is polyaluminum chloride.

As a preference, the three-phase internal circulating biological fluidized bed aerobic treatment process is also provided with fan jet aeration.

As a preference, the precipitation treatment process needs to add a polymer bioflocculant.

As a preference, the polymer bioflocculant is one or more of polyglutamic acid and polycystine.

As a preference, the clear water in the upper layer needs to be disinfected with chlorine dioxide before it can be discharged.

Slaughter wastewater is firstly filtered through a mechanical grille to remove coarse debris such as fur, meat chips, and bone chips in the wastewater, so as to protect the subsequent pipeline equipment, facilitate the subsequent treatment process, and prevent the subsequent treatment pipeline from being contaminated by coarse substances. Damage, affect the efficiency and service life of equipment.

Since there are many kinds of sundries contained in untreated raw slaughter wastewater, and the sundries have a wide range of sizes, in addition to the slaughter itself, it may also contain various tools, brackets and other substances used for slaughter. In order to prevent sundries from The grills are piled up to improve the screening efficiency of the grills. Set up two sets of grills for preliminary treatment of wastewater, and the coarse grills are in front, and the fine grills are behind. The gap between the bars is 4mm. The purpose of this setting is to realize the batch treatment of wastewater impurities. The wastewater first filters the substances with larger particle sizes through the coarse grid, and then filters and removes the substances with smaller particles through the fine grid, which can not only improve The treatment efficiency of impurities makes the filtration of impurities more thorough and clean, and prevents the quality problems caused by the piles of impurities on the grille, so as to achieve the purpose of economical benefits.

The waste water that has been roughly treated by the grid flows into the grease trap for grease treatment. In order to collect the grease floating on the surface, a reciprocating oil scraping device is installed on the upper part of the grease trap. After the grease is collected, it is sent to a professional factory for treatment. The waste water then flows into the coagulation sedimentation tank to further remove residual grease, hair and other sundries, and remove pollutants whose specific gravity is greater than that of water. In order to improve the cohesion of impurities and remove more polluting impurities in the wastewater, coagulation chemicals should be added to the coagulation sedimentation tank to help the impurities coagulate and precipitate each other. The oil separation and coagulation sedimentation process not only plays the role of oil separation and sedimentation to obtain sewage with low oil content and suspended solids concentration, but also adjusts and averages the sewage through the oil separation tank and sedimentation tank to reduce the amount and quality of sewage The fluctuations provide the best stable operating conditions for subsequent processing.

After passing through the grease trap and the coagulation sedimentation tank, the wastewater enters the anaerobic internal circulation biological fluidized bed, and the fluidized bed device is filled with porous, large-specific-area carriers, and the dominant anaerobic microorganisms evenly attach to the carrier to form a microbial film. Among them, the anaerobic microorganisms are bacteria, actinomycetes and mycoplasma. Wastewater flows through the carrier at a speed of 1.5-2.5m/h, fluidizes the carrier, anaerobic bacteria attach to the carrier and circulates in the fluidized bed, and is not easy to be lost with the wastewater, and the wastewater and anaerobic microorganisms are separated by vulcanization. Full contact strengthens the mass transfer between organic matter and biofilm, frequent collisions and frictions between particles make it difficult for biofilm to grow thick, macromolecular organic matter and refractory organic matter are fully decomposed, and wastewater COD is effectively reduced . In order to maintain a higher fluidization velocity and improve the reaction efficiency of anaerobic microorganisms and organic matter, a larger reflux ratio of 1 to 3 is required.

The wastewater after anaerobic treatment enters the three-phase internal circulation biological fluidized bed processor, and a porous carrier with a large specific area is placed in the fluidized bed, and aerobic microorganisms attach to the carrier to form a microbial film. Among them, aerobic microorganisms refer to the process of growth and reproduction in an aerobic environment, oxidizing organic or inorganic substances, and performing aerobic respiration with molecular oxygen as the final electron acceptor, including bacteria, actinomycetes and fungi. Under the action of air, the surface of the biofilm is constantly renewed, and the microorganisms in the device are maintained at a vigorous growth stage, and the full contact of air, wastewater, and microorganisms is achieved through vulcanization. The microorganisms on the biofilm absorb organic pollutants in the sewage as Nutrition, oxidize and decompose the organic matter in the wastewater into relatively stable inorganic matter, purify the sewage, and further reduce the COD index of the wastewater.

The three-phase internal circulation biological fluidized bed reactor has a compact structure and a small footprint. The upflow zone and downflow zone are combined together, and it contains fan jet aeration to provide sufficient gas volume and required gas velocity. The fluidization performance of the carrier in the fluidized bed is good, the mass transfer rate of oxygen is high, the residence time of microorganisms in the reactor can be extended and controlled, the oxidation and decomposition rate of organic matter in the wastewater is high, the efficiency of impurity treatment is fast, and it is clean and thorough.

The combination of "anaerobic internal circulation biological fluidized bed" and "three-phase internal circulation biological fluidized bed" for slaughter wastewater treatment is the innovation point and the biggest improvement point of this process. The combination of anaerobic and aerobic methods is used for wastewater treatment. The removal efficiency of organic matter and ammonia nitrogen in wastewater is high, and it also has a certain effect of nitrogen and phosphorus removal. The anaerobic internal circulation biological fluidized bed and the aerobic three-phase internal circulation biological fluidized bed are connected in series, the dissolved oxygen in the anaerobic internal circulation biological fluidized bed is not more than 0.2mg/L, and the aerobic three-phase internal circulation biological fluidized 2~4mg/L dissolved oxygen. The heterotrophic bacteria in the anaerobic internal circulation biological fluidized bed hydrolyze the suspended pollutants such as starch, fiber, carbohydrates and soluble organic matter in the sewage into organic acids, decompose the macromolecular organic matter into small molecular organic matter, and convert the insoluble organic matter into soluble organic matter. Organic matter, when these anaerobic hydrolysis products enter the three-phase internal circulating biological fluidized bed for aerobic treatment, the biodegradability and oxidation efficiency of sewage can be improved. In the anaerobic section, heterotrophic bacteria ammoniate pollutants such as protein and fat (N on the organic chain or amino groups in amino acids) to release ammonia (NH3, NH4+). Nitrification oxidizes NH3-N (NH4+) to NO3-, which is returned to the anaerobic internal circulation biological fluidized bed through reflux control, and the denitrification of heterotrophic bacteria reduces NO3- to molecular nitrogen (N2) to complete C, N , O cycle in the ecology, realize the harmless treatment of sewage. It can be seen from the above that the method of anaerobic-aerobic combination, anaerobic first, treats the macromolecular pollutants in the wastewater, effectively reduces the organic load for the three-phase internal circulation biological fluidized bed, and has the advantages of sludge circulation. The function of nitrogen and phosphorus removal is higher than that of a single aerobic or anaerobic method for the removal of waste water containing protein, fat and other macromolecular pollutants, and it also has the effect of nitrogen and phosphorus removal. Anaerobic internal circulation biological fluidized bed and aerobic three-phase internal circulation biological fluidized bed both combine the principle of fluidization with sewage treatment, mainly to solve the problem of low liquid-solid, gas-liquid contact efficiency in the process of sewage treatment question.

After aerobic treatment in the three-phase internal circulating biological fluidized bed, the effluent enters the sedimentation tank, and the upper clear water is sterilized by chlorine dioxide and discharged up to the standard. The sedimentation treatment process adds some polymer bioflocculants, such as polyglutamic acid, polycystine and other biodegradable flocculants, to reduce the amount of sludge generated, reduce secondary pollution, and transport the sludge formed by sedimentation to sludge pool.

Beneficial effects of the present invention:

1. The wastewater treatment process of the present invention is simple, reliable in operation, and good in stability, and solves the limitations of scale, capital, and technical conditions that small and medium-sized enterprises are subjected to when adopting traditional treatment methods.

2. The wastewater treatment process of the present invention is aimed at the characteristics of large changes in the quality and quantity of slaughter wastewater, high COD, ammonia nitrogen, and SS, and adopts an anaerobic internal circulation biological fluidized bed and a three-phase internal circulation biological fluidized bed to jointly treat slaughter wastewater. The biological method is energy-saving and environmentally friendly, and the three-phase fluidized bed has the characteristics of high reaction efficiency and strong operating flexibility. It uses porous, large specific surface area particles, stable film formation, and large biofilm area biological carriers to treat wastewater. While effectively decomposing, it realizes the harmless treatment of sewage and achieves the effect of environmental protection.

3. The wastewater treatment process of the present invention has the advantages of shortened wastewater treatment time, strong impact load resistance, compact equipment layout, large processing capacity, small footprint, flexible operation, and strong adaptability, and is convenient for integration and standardization , serialization, low production cost, short construction period, suitable for wastewater treatment of small and medium-sized slaughtering enterprises.

Description of drawings

Fig. 1 is a process flow chart of the present invention for the treatment of livestock slaughter wastewater.

Detailed ways

The slaughter wastewater treatment process of the present invention will be described in detail below in conjunction with specific examples, but the following examples are not intended to limit the technical solution of the present invention.

The livestock slaughter wastewater treatment process of the present invention mainly comprises the following steps:

The COD content of untreated imported wastewater is 2200-6500mg/L, the ammonia nitrogen content is 105-185mg/L, the SS>10000mg/L, and the oil content>3000mg/L.

1. The slaughter wastewater is firstly filtered through the mechanical grid made of bars to remove the slag, and the fur, meat chips, bone chips and other coarse debris in the wastewater are removed to protect the subsequent pipeline equipment and prevent the subsequent pipeline equipment from being coarse and debris material damage, and facilitate subsequent processing. Among them, the mechanical screen is divided into coarse screen and fine screen. The waste water first passes through the coarse screen to remove the debris with larger particles, and then passes through the fine screen to remove the debris with smaller particles. The gap between the coarse grid and the strip is 20mm, the gap between the fine grid and the strip is 4mm, and the flow velocity of the wastewater is less than 0.5m/s.

2. The waste water that has been roughly treated by the grille flows into the grease trap. Under the action of the reciprocating oil scraping device installed on the upper part of the grease trap, the grease floating on the surface is collected, and the collected grease is sent to a professional treatment factory. In this embodiment, the oil content of the waste water at the inlet of the oil separation tank is >3000mg/L, and the oil content at the outlet is reduced to <200 mg/L. The oil content test instrument of the waste water adopts the OiL-8 infrared oil measuring instrument according to the "water quality petroleum and animal and vegetable oil Determination of infrared photometry" (GB/T16488-1996) national standard implementation. The waste water treated by the grease trap flows into the coagulation sedimentation tank, and the coagulation drug polyaluminum chloride (PAC) is added for precipitation to further remove residual grease, hair and other sundries, and remove pollutants whose specific gravity is greater than that of water. The treatment time of the coagulation sedimentation tank is 1.5 hours, and the water velocity of the surface area of the sedimentation tank is less than 1.5m ³ /m ² ·h). In this embodiment, the suspended solids content at the inlet of the coagulation sedimentation tank is SS>10000mg/L, and the suspended solids content at the outlet is SS<850mg/L. Among them, the measurement of suspended matter content in wastewater is carried out according to the gravimetric method of GB/T11901-1989 water quality suspended matter.

3. The wastewater after the oil-separating precipitation treatment enters the anaerobic internal circulation biological fluidized bed for anaerobic treatment. Under the sulfidation of the wastewater, the carrier circulates in the fluidized bed, and the anaerobic microorganisms attached to the carrier and the wastewater fully Contact, decompose macromolecular organic matter and refractory organic matter, effectively reduce the COD of wastewater, and achieve the cleaning effect of wastewater. The anaerobic treatment time is generally more than 12 hours, the volume ratio of the carrier particles is 15%, and the wastewater flow rate is 1-2.5m/h. In this example, the COD of the inlet wastewater of the anaerobic internal circulating fluidized bed is 2200-6500mg/L, and the outlet wastewater COD<1800mg/L.

4. The wastewater after anaerobic treatment enters the three-phase internal circulation biological fluidized bed processor for aerobic treatment. Aerobic microorganisms attach to the carrier to form a microbial film, and the fan jet aerates the air, wastewater, and microorganisms in the fluidized bed. With the full contact of the three phases, the aerobic microorganisms on the biofilm absorb the organic pollutants in the sewage as nutrients, oxidize and decompose the organic substances in the wastewater into relatively stable inorganic substances, purify the sewage, and further reduce the COD index of the wastewater. The itching treatment time is 8 hours, the volume ratio of the carrier particles is 10%, the fluidization power in the aerobic three-phase internal circulation mainly comes from the fan, the air volume of the fan is less than 300L/h, and the hydraulic retention time is less than 10 hours. In this example, the COD of the wastewater at the outlet of the aerobic three-phase internal circulating biological fluidized bed was less than 120 mg/L.

5. After aerobic treatment, the effluent of the three-phase internal circulation biological fluidized bed processor enters the sedimentation tank, and the supernatant water is sterilized by chlorine dioxide and discharged after reaching the standard. The sedimentation treatment process adds polymer biological flocculants, such as polyglutamic acid, polycystine and other flocculants, to reduce the amount of sludge produced and reduce secondary pollution. The sludge formed by precipitation is transported to the sludge tank. Among them, the treatment time of the sedimentation tank is about 1.5 hours, the concentration of the polymer biological flocculant is 0.2g/L, the concentration of chlorine dioxide is 3g/m ³ , and the disinfection time is 10-20 minutes.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (9)

1. a treatment process for livestock slaughter wastewater, characterized in that it may further comprise the steps: 1) Filter the waste water through a mechanical grid to remove slag; 2) The wastewater that has been roughly treated by the grid flows into the grease trap and the coagulation sedimentation tank in turn for grease trap and sedimentation treatment; 3) The wastewater treated by oil separation precipitation enters the anaerobic internal circulation biological fluidized bed to decompose macromolecular organic matter and refractory organic matter; 4) The wastewater after anaerobic treatment enters the three-phase internal circulating biological fluidized bed for aerobic treatment, and oxidizes and decomposes the organic matter in the sewage into relatively stable inorganic matter; 5) The effluent after aerobic treatment is subjected to sedimentation treatment, the sludge enters the sludge tank, and the upper clear water is discharged after being treated up to the standard. 2. The treatment process of a kind of livestock slaughter wastewater as claimed in claim 1, characterized in that, the mechanical grids are two groups, the coarse grids are in front, the fine grids are behind, and the gaps between the coarse grids are deleted. It is 20mm, and the gap between the thin grille is 4mm. 3. A treatment process for livestock slaughter wastewater as claimed in claim 1, wherein a reciprocating oil scraping device is installed on the upper part of the grease trap. 4. A treatment process for livestock slaughter wastewater as claimed in claim 1, wherein coagulation chemicals need to be added to the coagulation sedimentation tank for precipitation. 5. A treatment process for livestock slaughter wastewater as claimed in claim 4, wherein the coagulation medicine is polyaluminum chloride. 6 . A treatment process for livestock slaughter wastewater as claimed in claim 1 , wherein said three-phase internal circulating biological fluidized bed aerobic treatment process is also provided with fan jet aeration. 7 . 7. A treatment process for livestock slaughter wastewater as claimed in claim 1, characterized in that, in the step 5, the precipitation treatment process needs to add a polymer biological flocculant. 8 . A treatment process for livestock slaughter wastewater as claimed in claim 7 , wherein the polymer bioflocculant is one or more of polyglutamic acid and polycystine. 9. A treatment process for livestock slaughter wastewater as claimed in claim 1, wherein the upper layer of clear water needs to be disinfected with chlorine dioxide to meet the standard before it can be discharged.