In recent years, with the rapid growth of the food industry, the waste water discharged by it greatly pollutes the environment, and loses a lot of energy and water resources, which in turn restricts its own growth. Due to the severe lack of resources in the face of the world at this stage, it is urgent to choose the appropriate waste water disposal punishment to achieve the goal of water saving and energy saving.

The important source of sewage in food industry is the process of food processing, such as punishment, washing, dehydration, filtration, dispersing and refining, deacidification, deodorization and cooking. Sewage contains a large amount of egg white, organic acids and carbohydrates. Due to the existence of many plankton, dissolved organic matter in water grows rapidly, and humus is easy to occur and accompanied by unpleasant gas. At the same time, copper, lead, manganese, chromium and other metal ions other metal ions in these sewage, and bacteria and coliform bacteria often exceed the national discharge scale.

The important pollutants in wastewater are (1) solid substances, such as vegetable leaves, pericarp, minced meat and poultry feathers, etc .;(2) oil, egg white, starch, colloid, etc .;(3) acid, alkali, salt, sugar, etc. dissolved in wastewater :(4) mud sand and other organic matter entrained by qualitative materials ;(5) pathogenic bacteria, etc. Food industry wastewater is characterized by high organic matter and suspended matter content, easy to erosion, the same usually no toxicity. Its harm is to make the water body eutrophication, so as to cause aquatic animals and fish to die, promote the accumulation of organic matter under the water odor, deterioration of water quality pollute the environment.

Since there are many kinds of food, there are many kinds of material springs, the sewage of food industry has the characteristics of suspended matter, high oil content, heavy metal ions, large COD and BOD value, large range of water quality and quantity change, high content of nitrogen and phosphorus compounds, and high water temperature in some environments. Therefore, the punishment of sewage disposal in food industry is usually to accept solid-liquid dispersion skills to remove suspended matter and drifters from sewage to reach the sewage discharge scale.

Solid-liquid dispersion skills we accept Zhejiang Sanlian environmental protection machine equipment deployment Co., Ltd. LW spiral discharge settling machine. It is important to be used in the field of solid and liquid dispersion in all living wastewater, industrial wastewater, chemical, food, pharmaceutical and similar production industries.

The process of wastewater from the food industry is as follows:

The suspension of wastewater in the food industry enters the drum through the feed pipe from the spiral outlet. Under the action of the centrifuge in which the high speed rotation takes place, the solid particles with large specific gravity are deposited on the inner wall of the drum. After dispersing the clear night through the liquid layer adjustment plate opening overflow and flow drum. The relative activity between the spiral body and the drum (that is, the differential speed) is realized by the differential, and its fineness is controlled by the auxiliary motor, thus realizing the continuous dispersion of the centrifuge to the material.

All kinds of waste water biological disposal punishment system is constantly emerging, the above-mentioned food wastewater is to accept the new solid-liquid dispersion skills, with high use rate, simple installation, wide application scope and other advantages, and has been put into practice in foreign countries, to achieve success. We can learn from the disposal and punishment skills of these ancestors, and trust that with the continuous strengthening of people’s awareness of environmental protection, the water environment of our country will certainly change.

Filter press and horizontal screw centrifuge are common solid-liquid separation equipment, the amount of retention is very large, rich sunshine and you solid-liquid separation production line machine from filter press to horizontal screw centrifuge technical advantages:

1. horizontal centrifuge without filter media,

Filter press pressure filtration of filter medium (filter) to separate solid and liquid, need to use high pressure water to avoid filter belt obstruction; horizontal centrifuge high speed rotation to produce Li Xin position to separate solid-liquid centrifugal settlement, It is not suitable for filter medium because of filter screen, which bypasses the common filter clogging problem in filter operation.

2. horizontal screw centrifuge is widely applicable

Filter press can also most of the solid-liquid separation, but the oil, viscosity and other strong adhesion of solid-liquid separation needs pretreatment and incomplete separation; horizontal screw centrifuge separation adaptability, can achieve solid-liquid two-phase separation and solid-liquid three-phase separation, better adaptability to solid-liquid separation.

3.Automation of production line of 3. horizontal screw centrifuge:

Filter press is intermittent operation of manual cutting slag, loading and unloading belong to intermittent operation most or need manual coordination is not conducive to the formation of automatic production line to improve production efficiency; Horizontal centrifuge can realize automatic loading and unloading continuous production automatic loading and unloading can form automatic production line production efficiency.

4. horizontal screw centrifuge parameters adaptive adjustment ability,

In the process of solid-liquid separation and dehydration, the belt filter is adjusted according to the working conditions, and the parameters such as speed, tension, dosage and flushing pressure often depend on the experience of the operator, which requires high operation technology.

5.Low consumption of pre-treatment material for 5. screw centrifuge

Because filter press filter medium (mainly filter net) mesh will not be very small, so filter particle size can not be too small, small particle size should also add a lot of flocculant complex to synthesize large groups to facilitate filtration, which results in the consumption of additional pretreatment materials. In horizontal centrifuge, fine sludge can also be separated from water, so the dosage of flocculant is less, saving material input and reducing production cost;

6. horizontal screw centrifuge production line environment is good:

In addition to the main filter press, the filter press also needs to add medicine and feed conveyor washing pump air compressor and other ancillary equipment, large area, the whole machine is difficult to seal, high pressure cleaning water mist and odor pollution environment, poor production line environment;

7. low maintenance requirements for horizontal centrifuge

The number of easily damaged parts in the fuselage accessories of filter press is many times that of centrifuge. Maintenance is not only labor intensity but also high cost.

It can be seen from the above comparison that the comparison of the same processing conditions with the filter press has great technical advantages, and the solid-liquid separation production line from the filter press to the horizontal screw centrifuge is the development trend.

The solid-liquid separation capacity of horizontal screw centrifuge is strong, high efficiency and high treatment capacity. It has been widely used in sewage treatment in China, which greatly reduces the cost of sewage treatment and creates huge economic value and social environmental protection value. Here are some common operational problems for Decanter centrifuge in sewage treatment, GN discuss with you.

Decanter centrifuge is not easy —— selection is important:

The equipment principle is based on the specific gravity difference of solid and liquid to accelerate the settlement of solid and liquid by applying centrifugal force field to achieve the purpose of separation. Because there may be some differences in the parameters of different fuselage components in the design of Decanter centrifuge, such as slag discharge ability and drum requirement. Since the horizontal screw centrifugation and the use of bias, since it is sewage treatment, in the selection of course, only to buy suitable for the sewage treatment process of centrifugal separator equipment can achieve twice the result with half the effort.

Disstable separation effect —— parameter adjustment are important:

Although the parameter setting habits of each manufacturer are different, in general, in order to better cope with the material change and enhance the general performance of the machine, the commonly used adjustment of the required parameters include the speed adjustment of the drum, the speed difference adjustment of the push differential, and the height of the overflow plate. For different materials, you are too lazy to adjust the parameters to make the machine more suitable. It is really difficult to imagine what kind of teasing performance the engineering mud desliming parameters will have ~ directly to the wastewater treatment of the steel plant

Disparation effect is not good —— pretreatment is important

For the next stage of solid-liquid separation of horizontal screw centrifuge to do a good pretreatment, to achieve the best separation effect;

Decanter centrifuge is easy to damage —— production operation maintenance techniques are important:

Decanter centrifuge is suitable for frequent failures, can not be wronged you, this may be due to poor material applicability, such as material slurry impurities too much, feed too fierce resulting in slag discharge is not smooth, rotary block…

However, most of the feed impurities can be added to the material pretreatment section, the discharge is not smooth can be adjusted according to the material characteristics of the push speed difference, block can always check whether there is a lack of lubricating oil or foreign body stuck in the rotating shaft, These causes of Decanter centrifuge failure can be said to have nothing to do with the operator?

I. Widespread application

1. suitable for municipal sewage, food, beverage, chemical, leather, welding materials, paper, printing and dyeing, pharmaceutical and other industries sludge.

2. suitable for dewatering high and low concentration sludge. For low concentration (2000 mg/L~) sludge dewatering, there is no need to build concentration tank, storage tank, reduce construction cost, reduce phosphorus release and anaerobic odor production.

II. Small-scale design

1. Compact design, the dehydrator contains electronic control cabinet, metering tank, flocculation mixing tank and dehydrator body.

2. space is small, easy to repair and replace; small weight, easy to carry.

III. Not easily blocked

1. has the function of self-cleaning. There is no need to clean to prevent clogging, reduce washing water consumption and reduce internal circulation burden.

2. is good at dewatering oily sludge.

 IV. Low speed operation

1. The speed of the screw shaft is about 2~3 rpm, and the power consumption is very low.

2. failure is less, noise vibration is small, operation is safe.

V. Simple operation

1. through the electronic control cabinet, with the bubble medicine machine, mud pump, dosing pump, etc., to achieve 24 hours of continuous unmanned operation.

2. daily maintenance time is short, maintenance operation is simple.

VI. Durable

1. Almost all thebody is made of stainless steel, which can prolong the service life to the maximum extent.

2. replacement parts only spiral shaft and swimming ring, long service period.

 VII. Low investment costs

1.  Various product specifications, complete series, for different processing scale, can choose the most suitable model, to avoid overuse.

•  The body is compact in design, integrated in concentration and dewatering, with auxiliary devices such as electronic control cabinet and sludge flocculation mixing tank, which has strong compatibility with supporting equipment and is easy to design.

•  Small design, easy to adapt to local conditions, can reduce the dehydrator itself space and construction costs.

•  It has the function of sludge concentration, so it does not need to concentrate and store units to reduce the overall space and construction cost of sewage treatment facilities.

•  The main body of the dehydrator has the function of self-cleaning, so it is not necessary to use a large amount of water to prevent sludge clogging.

•  Adopt low speed spiral extrusion technology, low power consumption.

•  The electronic control cabinet is equipped with automatic control device, from conveying sludge, injecting medicine liquid, concentrating and dewatering, to discharging mud cake, realizing 24 hours automatic continuous unmanned operation and reducing workers’ expenses.

3.Characteristics of oily wastewater and its treatment methods

Oily wastewater mainly comes from petroleum, petrochemical, iron and steel, coking, gas generating station, machining and other industrial sectors. Except for the relative density of heavy tar above 1.1, the relative density of oil pollutants in wastewater is less than 1. Oil usually exists in three states in wastewater. (1) Oil slick, oil droplet size greater than 100 um, easy to separate from wastewater ;(2) dispersed oil, oil droplet size between 10~100 um, suspended in water ;(3) emulsified oil, oil droplet size less than 10 um, not easy to separate from wastewater. Waste due to different industrial sectors  The concentration of oil in water varies greatly, such as wastewater produced in refining process, oil content is 150~1000 mg\L, tar content in coking wastewater is about 500~800. Therefore, the treatment of oily wastewater should first use cadmium oil tank, recovery oil slick or heavy oil, treatment efficiency is 60~80, oil content in effluent is about 100~200 mg\L; emulsified oil and dispersed oil in wastewater are difficult to treat, Therefore, to prevent or reduce the phenomenon of emulsification. One of the methods is to reduce waste during production  The emulsification of oil in water; second, in the treatment process, as far as possible to reduce the number of pumps to lift the wastewater, so as not to increase the degree of emulsification. The treatment methods are usually air floatation and demulsification.

4.Characteristics of cyanide-containing wastewater and its treatment methods

Cyanide wastewater mainly comes from electroplating, gas, coking, metallurgy, metal processing, chemical fiber, plastics, pesticides, chemical industry and other departments. Cyanide wastewater is a kind of industrial wastewater with great toxicity, which is unstable in water and easy to decompose. Inorganic cyanide and organic cyanide are local toxic substances, and human ingestion can cause acute poisoning. The lethal dose of cyanide to human body is 0.18 g, potassium cyanide is 0.12 g, the mass concentration of cyanide to fish is 0.04~0.1 mg\L. in water The main treatment measures of cyanide-containing wastewater are as follows :(1) reforming the process to reduce or eliminate the effluents of cyanide-containing wastewater, such as using cyanide-free electroplating method to eliminate electroplating Workshop industrial wastewater. (2) Wastewater with high cyanide content should be recycled, and wastewater with low cyanide content should be purified and treated before discharge. The recovery methods include acidified aeration and lye absorption, steam desorption and so on. The treatment methods include alkaline chlorination, electrooxidation, pressurized hydrolysis, biochemistry, biological iron, ferrous sulfate, air blowing hair loss and so on. The alkaline chlorination method is widely used, the ferrous sulfate method is not thorough and stable, and the air blowing method not only pollutes the atmosphere, but also fails to meet the discharge standard.

A good design scheme can not be separated from the understanding of water quality; understanding the source and characteristics of wastewater and the production process is of great help to our design scheme and selection of treatment process. We plan to collect all kinds of industrial wastewater sources, characteristics and treatment methods, hope to be used for reference and sharing industrial water treatment industry colleagues, learn from each other, together for the development of water treatment industry in China.
Industrial wastewater refers to the wastewater discharged from the industrial production process, including process water, cooling water for machinery and equipment, flue gas washing water, equipment and site washing water, etc. Because of the variety of industrial types, each industry is composed of multi-stage processes, the properties of wastewater are completely different and the composition is very complex. According to the different harm caused by wastewater to environmental pollution, it can be roughly divided into solid pollutants, organic pollutants, oil pollutants, toxic pollutants, biological pollutants, acid and alkali pollutants, aerobic pollutants, nutritional pollutants, sensory pollutants and thermal pollution.

1. Characteristics and Treatment of Acid-base Wastewater

Acid wastewater mainly comes from iron and steel plants, chemical plants, dye plants, electroplating plants and mines, which contain various harmful substances or heavy metal salts. The mass fraction of acid varies greatly, the low is less than 1 and the high is more than 10. Alkaline wastewater mainly comes from printing and dyeing factory, leather factory, paper mill, refinery and so on. Some of them contain organic bases or inorganic bases. Some of the mass fractions of alkali are higher than 5 and some are lower than 1. Acid and alkali wastewater, in addition to containing acid and alkali, often contains acid salt. Basic salts and other inorganic and organic compounds.

 Acid and alkali wastewater has a strong corrosion, need to be properly treated before discharge.
 The principle of treating acid-base wastewater is:
 (1) High-concentration acid-base wastewater should be recycled as a matter of priority. According to the requirements of water quality, quantity of water and different processes, plant or regional scheduling should be carried out for reuse as far as possible; if reuse is difficult, or if the concentration is low and the quantity of water is large, acid-base can be recovered by concentrated method.
 (2) Low-concentration acid-base wastewater, such as cleaning water from pickling tanks and rinsing water from alkali washing tanks, shall be neutralized.

For neutralization treatment, the principle of waste treatment should be considered first. For example, acid and alkali wastewater neutralize each other or use waste alkali (slag) to neutralize acid wastewater, and use waste acid to neutralize alkaline wastewater. In the absence of these conditions, neutralizers can be used.

According to the requirements of the new rural construction and the strengthening of people’s awareness of environmental protection and energy conservation, now, pig farms build biogas digesters and biochemical ponds to treat feces and urine, but the fecal materials into biogas digesters have not been separated from solid and liquid. The actual use proves that the direct biogas culture effect is not ideal. Because untreated fecal water enters the biogas digester, the organic load per unit volume of the biogas digester is greatly increased, so the volume of the biogas digester is much increased.

Because of the long-term use of biogas digester, a large amount of residue is left behind after fermentation, which makes the biogas digester blocked and the capacity decreases, which results in the biogas digester can not be used, and the cleaning pool is extremely inefficient and unsafe, and the cost is increased at the same time. If the direct sale of fresh pig manure is difficult to transport. Therefore, we find that solid-liquid separation measures should be carried out before pig manure, which can not only solve the problem of pig manure precipitation in biogas digesters, greatly enhance the treatment capacity of biogas digesters, but also greatly reduce the construction area of biogas digesters and biochemical ponds.

Save the construction investment and land use area of environmental protection treatment, the separated pig manure can also be directly used as fruit trees, tree fertilization and organic fertilizer raw materials. Sell to organic fertilizer plant as organic fertilizer raw material or self-made organic fertilizer, both social and economic benefits. This machine can be widely used as chicken, cattle, horse and all kinds of intensive farms for the separation of animal feces, distiller’s grains, residue, starch residue, sauce residue, slaughtering plant and other high concentration organic sewage residue.

The practicability of flat centrifuge: the separation speed of slag liquid is fast, the moisture content of fecal slag after separation is between 50-60%, the amount of slag and water content can be adjusted, it can be used for different ingredients of feed (such as grass and concentrate feed), easy to transport, Its solid particles are suitable for fish feed and organic fertilizer raw materials.

Advanced: flat centrifuge decontamination ability, no blockage, easy to clean. The solid content, chemical oxygen consumption, total oxygen consumption, nitrogen and phosphorus removal rate of treated fecal and urine water can be between 70 and 95% respectively.

Durability: the frame, sieve frame, screen and so on of plate centrifuge are made of stainless steel and anticorrosion treatment, etc., corrosion resistance, high strength, long service life.

Economy: flat centrifuge automation, low power consumption, low price. Easy to operate simply press the start stop button

Before the introduction of decanter centrifuge into the field of tailings recovery, the traditional way is to discharge a large amount of unqualified tailings. With the deepening of the concept of environmental protection, the mineral processing industry can not find a balance between water pollution control and production, which seriously restricts the healthy development of tailings washing industry. The following three advantages of decanter centrifuge in tailings washing field are discussed to discuss the adaptability value of centrifuge to industry.

Separation and recycling of tailings solid-liquid by decanter centrifuge:

The decanter centrifuge is introduced into the field of washing washing and pollution control. The sewage pretreatment is added with precipitator flocculant and then entered into the purification tank. First, the concentrate powder in the tailings washing wastewater is separated by the horizontal screw centrifugal solid liquid, which increases the utilization efficiency of resources and reduces the waste of resources.

Regeneration and utilization of mineral processing wastewater by decanter centrifuge:

The pretreatment water quality of tailings washing wastewater by decanter centrifuge can participate in production again, and participate in production recycling again to save cost or discharge. The recycling of water resources reduces the consumption of water resources in the industry, not only reduces the cost, but also saves energy and is more environmentally friendly;

Adding added value to tailings particle classification by decanter centrifuge:

Recovery of concentrate powder, in the decanter centrifuge solid-liquid separation stage can be selected and graded ore powder particle size, purification and classification of concentrate powder quality, increased the value-added deduction cost to create value;

GN decanter centrifuge separation precision high processing capacity is small, the use of decanter centrifuge to treat wastewater to the original sedimentation tank transport pipeline compatibility, no major changes to reduce the cost of capital construction, Because of the advantages of simple operation, low processing cost and reliable operation, solid-liquid separation has been widely used in sewage treatment industry.

The above is about the case of decanter centrifuge turning waste into treasure into profit in the separation of solid liquid from tailings of concentrator. Through the input-output ratio of decanter centrifuge to demonstrate the value of creating wealth of centrifuge equipment, Wealth is around only in the pitch between hope to inspire you!

GN has a range of tailing washing decanter centrifuges for you choice. Please contact us for more information.

The spiral sedimentation centrifuge has reasonable structure, advanced technology and fine manufacture. It can concentrate, dehydrate or separate solid particles in the range of several microns to three millimeters.
Product characteristics :

1, Good adaptability: in the process of fully considering the material, the process of various special requirements for centrifuges, the primary components of the implementation of special, adjustable optimization design. As long as the user before the purchase of the installation and use of the place, material processing physical and chemical characteristics, process requirements and so on, we will provide users with the most suitable model. High degree of

• Automation: centrifuge in the work of feeding, separation, unloading, and other processes are carried out in high speed continuous automatic operation. The automatic control of centrifugal separation and centrifugal scour process is completed by programmable controller.
• Stability The differential used in centrifuge is cycloid wheel differential or planetary wheel differential, which has the characteristics of large torque and wide conditioning range.
• Performance is strong: the centrifuge adopts the double motor double frequency conversion energy reaction differential speed system to control, carries on the flexible stepless conditioning to the differential speed, and adjusts the differential speed at any time according to the material change. real energy saving products. Good
• Operation environment: centrifuge separation of materials is carried out under completely closed conditions, to ensure that the operation site is neat, and to maintain the production environment neat and hygienic, to complete civilized production.
• Safety maintenance device is completely reliable: centrifuge with torque maintenance, power control and other multiple maintenance can effectively eliminate or reduce the damage caused by sudden failure to the machine. Beautiful 7. Shape: the machine seat is welded by carbon steel, the appearance is treated by special technology, lubrication is smooth.

The horizontal screw centrifuge is a equipment for separating suspension by centrifugal sedimentation principle. Its working principle is that when the separated suspension enters the drum of the centrifuge, the solid particles with higher density than the liquid phase quickly settle to the inner wall of the drum under the centrifugal force of the drum. The separated liquid flows out from the overflow Weir of the drum. This horizontal screw centrifuge can feed, separate, wash and unload continuously at full speed. Compact structure, continuous operation, smooth operation, strong adaptability, production Large capacity, convenient maintenance and other characteristics. suitable for separating suspensions with solid-containing particle size greater than 0.005 mm, concentration range of 2-40%. Widely used in chemical, light industry, pharmaceutical, food, environmental protection and other industries.

Screw conveyor is through rotating blade, push the material, widely used in building materials, chemical, electric power, metallurgy, coal mine, grain and other industries. Screw conveyor is suitable for horizontal or inclined conveying powder, granular and small block materials, the temperature of general materials should be less than 200℃, it is not suitable for conveying materials that are prone to deterioration, easy to caking or sticky. Today, we introduce the advantages and disadvantages of screw conveyor, which is convenient for customers to understand and use.

 I. Advantages of screw conveyors

 (1) Spiral shaft and shaft are connected by embedded tongue type, which makes installation, disassembly and maintenance very convenient and has less failure rate.

 (2) The screw conveyor adopts variable diameter structure, and the lifting bearing can not contact with the material, so its life is long.

 (3) It is not easy to jam or block the material when conveying, and the head and tail bearing seat is outside the shell, the seal of the bearing is good can be used for a long time.

(4) The structure is simple and the size is small, so the occupied area and space are not very large.

(5) There may be multiple feed and discharge ports, which can be arranged flexibly.

 (6) It is delivered in a reversible direction and therefore can be delivered in both directions.

 (7) Safe and reliable operation, can complete transportation, mixing, stirring, loose, heating and cooling processes.

 II. Disadvantages of screw conveyors

 (1) The friction between the blade, the casing and the material is relatively large, which makes the blade and the casing easy to wear, and the power consumption is also relatively large.

 (2) The transport distance is limited and can not exceed the maximum requirement.

 III. Selection of screw conveyor diameters

 For the screw diameter of the winch conveyor, the requirements should be met:

 In the case of conveying bulk material, the screw diameter shall be 10 times the maximum side length of the particle;

 If there are only a small number of large particles, the spiral diameter should be 4 times the maximum side length of the particle.

GN can customize screw conveyors upon customers’ request. No matter O-type or U-type, GN is able to fabricate quality products specially for clients’ needs and requirements. We have standard products for multiple usage. Please contact us if you are interested in this product.