Monthly Archives: August 2020

Introduction of Treatment Method for Industrial Wastewater(2)

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.

Introduction of Treatment Method for Industrial Wastewater

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.

Application of Centrifuge in Solid-liquid Separation of Rural Pigs’ Waste

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

The Value of Decanter Centrifuge in Tailings Washing Industry

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.