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GlobeCore sets course for East Africa. Uganda Electricity Transmission Company Limited and GlobeCore – a new partnership

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GlobeCore is a leading manufacturer of various equipment, such as transformer oil purification and regeneration plants, bitumen emulsion plants, bitumen modification plants, fuel blending systems and bio-diesel production system, employing over 200 staff on the production team. Our products are well known in the USA, Europe, Asia and Africa. While we are open to business anywhere in the world, we are also focusing on Africa.
GlobeCore is a lead manufacturer of variety equipments like Transformer Oil Purification and Regeneration Plants, Bitumen Emulsion Plants, Modified Bitumen Plants, Fuel Blending Systems and Bio Diesel Equipment. We are open to any country; now we are focus on African’s regions.
“GlobeCore’s representatives often travel to clients” – said mr.Sukhar, GlobeCore Export Manager – “we provide operators training and startup; separately we organize seminars to share our experience in oil purification and assets management”.
One such seminar was held in Kampala, the capital of Uganda last April. The focus of the seminar was the advantages of transformer oil regeneration by Fuller’s earth, and also on operational and environmental benefits of regenerating oil instead of replacing it.
Uganda and its neighboring countries are interested in electrical power development: within the next five years they will receive substantial investements from the World Bank to improve their national grids and make electricity accessible to population. At this time only 3 – 5% of Uganda’s population have access to electricity and there are many cities in the north of Uganda without electric power at all. Less than 2% of rural population has access to electricity, with less than half of that being provided by the national grid, other sources being household generators and solar panels.
As says Eugen Svirid, GlobeCore lead engineer, despite the growing importance of alternative energy, traditional power plants are the main providers of electricity around the world. These powers still need equipment replacements and modernizations.
Until Uganda receives the aid of almost 3.5 billion dollars over the next several years, which it needs for construction of Kawanda-Masaka transmission line and the related substation and 600MW power plant in Karuma, a lot can be done to preserve current assets – especially the most expensive of them, the power and distribution transformers.
Uganda Electricity Transmission Company Limited (UETCL) has teamed up with GlobeCore to upgrade their transformer oil purification plants. The company made its choice after a recommendation from Nigerian Power Holding Company, a partner of UETCL, which now operates eighteen GlobeCore mobile oil purification plants. UETCL fully understands the importance of transformer maintenance, says Christopher Mutyaba, the Head of Maintenance Department at UETCL. Accroding to him, transformer failures are, unfortunately, quite common, and cause frequent power outages. The population has to do without electrical power for six months, until a failed transformer can be repared or replaced. Mr. Mutyaba noted that transformer down time causes a significant loss revenue and growing customer dissatisfaction.
Latest GlobeCore technological developments will allow addressing the issue of excessive foam forming in the vacuum chamber which is often the case with old and contaminated oils. And as UETCL has many remote substation, oil purification plant will have fully automated control system with PLC and GSM module to minimize supervision.
German equipment is well known in Africa, especially in Uganda. Country operate transformer oil filtration machine purchased in 1991. While this equipment is still in fair condition, GlobeCore can replace most major components is required to satisfy higher demands for the quality of transformer oil, put on users by modern transformer manufacturers.

Fuller’s earth for industrial oil regeneration

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The one of the most used petrochemical products on production facilities is industrial oil and different types of this oil. Industrial oil is the most available and reliable for liquid insulation, for cooling and electrical protection for power transformers, turbines, hydraulic equipments etc.

fuller earthIndustrial oil has a lot of advantages which include long lifetime (without adding of antioxidizing additives – from 3 to 10 years); continuous working and protection of industrial systems. So the question concerning using other type of oil arises not frequently. Other advantage of industrial oil is reasonable price; also this oil is not so aggressive for environmental, industrial oil not produce the burned gas or other wastes which pollute the atmosphere.

Industrial oil has only one problem – utilization after usage. It is the problem which is the most discussed in our days. The main questions are decline of pollution charges, complete refill of used oil inside of engines and systems, reduction of the expenses for buying, shipping, preparation and maintenance of new oil etc.

The modern solution for all these problems concerning refilling of used industrial oil is usage of complex systems for oil filtration, degassing, re-refining and regeneration which are use different adsorbtion components.

industrial oil before and after regeneration

Industrial oil before and after regeneration.

It was investigated that the most effective result can be obtained when during one purification cycle the unit restores all characteristics of the oil and also exists the possibility of recirculation of all components of purification system, including adsorbing agents.

Fuller’s earth is very popular and most used component for industrial oil regeneration (oil recycling) all over the world.

Fuller’s earth is highly active bleaching clay with pronouncedsorption properties. This earth is famous also by its mineral composition. Fuller’s earth consists of hydrated aluminium silicates which contain metal ions (magnesium, natrium and calcium).

Montmorillonite is the principal clay mineral from which is composed Fuller’s earth. The presence and ratio of other minerals such as kaolinite, attapulgite and palygorskite depends from the changes in chemical composition. This component looks like clay but it has fine structure, higher water content and has no natural clayey plastic property. By means of it adsorbing agent Fuller’s earth retains the moisture.

The deposits of this type of clay were found all over the world. The main Fuller’s earth deposits are located in United Kingdom, Japan and USA.

Fuller’s earth is wide used in industrial branches and in medicine and cosmetology.

For oil regeneration this component is irreplaceable. Fuller’s Earth is used for purification of mineral and vegetable oils and greases.

The latest technologies in oil regeneration allow using all properties of Fuller’s earth in complex systems.

On our new units for transformer oil regeneration we use the system which allows restore all oil characteristics (by using Fuller’s earth) and at the same time exhausted clay can be also regenerated in the same unit.

Designed equipment for oil regeneration with the Fuller’s earth as an adsorbing agent corresponds to all ecological and technological trends and standards. This type of units for oil restoration filled another gap in the market of direct and alternative usage of mineral products.

Engineers from GlobeCore company have designed different equipment for mineral oils regeneration (transformer oil, industrial oil, turbine oil, diesel oil, heating oil, diesel fuel, gas condensate, kerosene etc).  On this website you can find a lot of interesting information concerning oil recycling and oil regeneration

Turn the waste into profits. Waste oil recycling machine.

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Waste oil recycling machine

One of the aspects of successful development of each business is implementation of innovations. We all are searching every day new resources to obtain more profits. There exist the materials which can be used again and again but because of shortage of equipment or knowledge we cannot use it on 100%.

recycleHow many tons of used oil recycling machine are disposed every year? How many damages we bring to our environmental? Stop throw out your profit into wastes, start recycling and you will obtain the benefits.

So, how can we obtain the benefit from this type of wastes? Today’s technologies of oil recycling allow restore almost all used oil recycling machine. We offer you to familiarize with mineral oil regeneration technology.

Regeneration does more than restore the oil to its original, new condition. The cost for regeneration of 1 ton of oil is less than the cost for new oil. Besides, regenerated or recycled oil can be more effective to compare with new oil.

For restoration of used oils can be applied various technological operations which are based on physical, physicochemical and chemical processes. All these methods were created for cleaning oil from different contaminants and aging products.

As usual, the sequence of oil cleaning methods is following:

  • mechanical (for removal of free-water and solid particles);
  • thermophysical (vaporization and vacuum distillation);
  • physicochemical (coagulation, adsorption).

If these methods are not enough to remove all contaminants the chemical methods need to be used. But you need to know that chemical methods are accompanied by using of sophisticated equipment and heavy expenses.

There exist a lot of different technologies for oil recycling such as electrostatic purification, single-pass filtration, constant regeneration of oil by absorbents or thermal siphon filters, application of special oil anti-oxidation and contamination protection, constant concentration of anti-oxidation additive (ionol) etc.

We will speak today about complete oil regeneration by means of special type of sorbing agent combining with degassing and desludging processes.

These devices for complete oil regeneration were designed by engineers from company GlobeCore. Over ten years this technology is used with success in 80 countries around the globe.

By using machines of UVR type (Unit for Vacuum Regeneration of Oil) you can recycle following types of oil and fuel:

Waste oil recycling machine

  • transformer oil;
  • industrial oil;
  • turbine oil;
  • diesel oil;
  • diesel fuel;
  • gas condensate;
  • kerosene;
  • other type of mineral oils.

But UVR unit cannot restore motor oils or oils which contain some synthetic additives. On our website you can familiarize with the video materials concerning oil regeneration and oil recycling.

Characteristics which can be improved during oil regeneration:

– dielectric strength; – tan delta; – octane number; cetane number; – oil color etc.

There is other positive side of oil restoration; it is stability of regenerated oil for oxidizing.

Another but very effective criterion is water content. During oil replacement from the unit the water from the air can get to the new oil. As result, the water in the oil can lead to damage of the unit or to other problems.

Waste oil recycling machine

Diesel fuel before and after regeneration

Our engineers had designed devices which can resolve the problem described above. This is on-side oil regeneration. You don’t need to deenergize your machine (transformer or other devices) to provide oil cleaning.

UVR unit can be applied for regeneration of old used oils from storing. All these wastes which were a big problem for many companies can be turn into profit. We were tested different types of contaminated mineral oil. Even when we pass the oil through the unit only one time the result is perfect. Imagine only, old burned oil can be regenerated to the “like new” condition. On the pictures you can see the result of oil testing. Oil with the black color and bad smell after treating by means of UVR unit became light with the good aromatic and completely restored characteristics.

We also can offer you to make a reclaiming test of yours example of fuel (oil) to check the possibility of cleaning it.

Waste oil recycling can be a good business considering the growing oil usage and implementation of new environmental legislation. You will kill two birds with one stone: prevent the damage of the earth and save your money.

So, if you are interested in environment protection and would like the develop your business, you can contact us any time and we will send you all required information concerning the Oil Regeneration Technology and waste oil recycling machine.

Difference between Oil Purification and Oil Regeneration

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Oil regenerationGlobeCore’s Oil Regeneration (Reclamation) Units are “Two-in-One” industrial systems that not only Purify used and/or contaminated oil, but completely Regenerate/Reclaim the used oil and restore used oil to its original new condition.

This new, industry leading technology was designed by GlobeCore’s engineers and the UVR units can perform oil and fuel regeneration/reclamation at a fraction of the cost of replacing used oil with new oil.

Today we are going to learn the difference between “Oil Purification” and “Oil Regeneration/Reclamation” and why purification alone is no longer cost effective.

Fuelcleaning.GlobeCore.com

Oil Purification

Oil Purification is a process that eliminates and/or reduces contamination in the oil through a means of filtration, dehydration, degasification, or some other processes that essentially cleans the oil of water, gases, and particulate matter. The typical process involves mechanical filtration and vacuum degassing. It can be performed with the transformer online or offline.

Current purification methods are normally effective in the removal of gases, particulate matter (down to 0.2 microns) and some, but not all, of the water/moisture found in the used oil.  Typical oil purification methods are usually sufficient to correct “electrical voltage breakdown” (EVB) caused by a combination of particulate matter and water in the oil which is a very common condition found in transformers in service for more than a couple of years.

In order to maintain the dielectric and insulating properties of the oil, it is necessary to perform the purification process on a routine or scheduled maintenance basis.  The “Purification Process” however, is not a long term solution for a wet transformer.  Oil Purification removes only a small fraction of the water suspended or dissolved in the oil and does not remove water and acids from the Kraft Insulating Paper.  To obtain nearly all water removal from the transformer oil and paper, a more powerful and complete process called “Regeneration” must be applied.  This process is also known as Reclamation.

Oil Regeneration

Oil Regeneration: The GlobeCore “Two for One” Engineering Miracle.  Oil Regeneration is a process that not only completely purifies used transformer oil; it improves the oil color and removes substances such as acids, aldehides, ketones, etc. that the standard purification processes cannot remove.  Oil Regeneration therefore, performs all the purification processes and goes beyond the purification process by removing the water and other acids, contaminates and particulate matter from the oil and the rest of the transformer including the paper.

When the “regenerated oil” is placed back in the transformer, it is in the same condition as it was when new and unused.  Additionally, the Kraft Insulating Paper has been dried and the acids, particulate matter, watrer and other contaminants are effectively removed thereby extending the service life of the paper.

The GlobeCore Oil RegenerationProcess also known as the GlobeCore Process, does not replace the purification process, but incorporates purification into the complete regeneration process as the two processes are combined into one service process thereby saving time and money.  The GlobeCore Process services the entire transformer and not just the oil!

The GlobeCore UVR units provide onsite and online servicing through regeneration and sludge removal. The following is a list of benefits to using GlobeCore regeneration units:

  • Reduces moisture in the oil to below 10 ppm
  • Reduces acidity to less than 0.01mg KOH/g in the oil
  • Dielectric strength of the oil is improved to 70 kV or higher
  • Interfacial tension is improved up to 40 Dynes
  • The Tan Delta of the oil is improved to equal less than 0.001
  • Sludge suspended or dissolved in the oil is removed
  • Sludge deposits found elsewhere in the transformer are also removed
  • Particulate matter is removed down to 0.2 microns
  • The oxidation stability of the oil is restored to the original new oil condition
  • The color of the oil is restored to new condition
  • The dielectric strength of the solid insulation is improved
  • Degradation of the solid insulation is halted thereby extending the service life of the transformer

Oil purification alone is no longer an efficient and cost effective way of servicing and maintaining your transformers.  GlobeCore’s Oil Regeneration equipment will completely purify and place the used oil into the same new original condition it was in when first installed in the transformer. GlobeCore Oil Regeneration Equipment equals big savings and reduced electric service interruptions.

GlobeCore Oil Regeneration Advantages:

  • No oil transportation costs because the oil is saved
  • No large quantities of new oil is required
  • No used oil storage and disposal costs
  • No negative environmental impact from used oil disposal
  • No additional transformer maintenance costs because all sludge is dissolved and removed from the core, coils, windings, cooling fins, and ducts.
  • No contaminants remain in the transformer because the GlobeCore Process regenerates and purifies in one process
  • No vacuum drawing costs
  • No oil spillage danger because the automated process is completed while the transformer remains online with minimal human operation. No used oil is handled by the one man service crew.
  • No service disruption to down line customers because the transformer can remain energized and online during the process

GlobeCore’s Industry Leading “GlobeCore Process” provides many financial and environmental benefits as compared to simple oil replacement.  To start, the transformer can remain energized and online during the regeneration process.  Although the transformer must be de-energized when the GlobeCore Regeneration unit is connected to and disconnected from the transformer, the remaining regeneration process can be performed while the transformer remains in service providing electricity to your customers.

The GlobeCore “Regeneration Process” is superior to changing oil for several reasons. First, merely changing the oil leaves as much as 15% of the contaminated/used oil in the transformer coils and windings. The old dirty oil will then contaminate the new oil effectively reducing the service life of the new oil. Second, the Kraft Insulating Paper will retain the acids, moisture, and particulate matter that will continue to actively degrade the insulating paper and shorten service life.

The GlobeCore“Regeneration Process” removes 99% of all contaminates from the entire transformer including the paper, coils and windings.  The regeneration process leaves no dirty oil behind because the existing oil is restored to original new clean condition.  No dirt or sludge remains in the paper halting the degradation process thereby extending the service life of the insulating paper and the transformer.

Changing the oil is a process that can take three weeks or longer to perform and requires that the transformer be de-energized and taken offline. The GlobeCore Process can be performed in as little as one to five days by a one man crew and the transformer can remain in service during the process.

The GlobeCore Process eliminates the expense and environmental hazards in removing oil, refilling oil, transporting new and used oil, and disposing of used oil.

The GlobeCore Process also eliminates the possibility of mixing different brands of oils with different specifications to replace the original factory fill oil since the used oil is not replaced, but restored to original condition.

The GlobeCore Transformer Regeneration System can be used with new transformers to start a lifetime preventive maintenance program that will extend the service life of transformers between 5 and 10 years and possibly longer.

GlobeCore offers the new UVR units for both oil and fuel regeneration and are currently in use in more than 70 countries worldwide.

Advantages of GlobeCore Oil Regeneration Plants UVR units:

  • Regenerate nearly any type of mineral oils (e. g. transformer oil, insulating oil, industrial oil, turbine oil, dark heating or crude oil, dark gasoline, dark diesel oil, kerosene, gas condensates, etc.)
  • Removal of aromatics, unsaturated hydrocarbons, hydrogen sulfide and other additives
  • Removal of mechanical impurities, water, particulate matter, etc.
  • Restore and improve oils/fuels to like new condition
  • Protects the environment by eliminating oil waste
  • Low price to high benefit ratio with low operating costs

(It is not cost effective to regenerate used engine oil and used Diesel oil at this time)

The GlobeCore UVR plants/units are produced in the following configurations:

  • Framed
  • Containerized
  • Explosion proof (for regeneration of gas condensate, kerosene and other inflammable petroleum products).

To get more technical information about the GlobeCore reclamation plants/equipment, please call us or arrange a visit to our production facilities and we will demonstrate how the UVR systems work.

Its time to get with the Process;  The GlobeCore Process!

Latex and rubber production: application of AVS

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The bottlenecks in production of rubber and latex articles are long desintegration and mixing time, difficulty of uniform distribution of extenders and other ingredients into the caoutchouc and latex, long vulcanization time.

ruber2To activate particle surface of extender (for example, soot) it can be exposed to the grinding by ball or vibrating mills. But this processing way is labour-intensive and gives marginal effect. Most effective way is chemical modification of the extender.

One of the ways of kaolin chemical modification is based on the common sedimentation of kaolin and calcium silicate suspension. In this case calcium silicate is generated during the blending of sodium silicate solution with calcium chloride.

It was investigated that kaolin surface activation in AVS unit leads to increasing of the durability of rubber-based vulcanizate to 84,3%.

Modification of the extender leads to increasing of durability of the vulcanizate. It can be explained by creation of adsorbed layer of modifying agent on the kaolin particle surface which helps to adsorption and chemical bond formation between the particles of extender and caoutchouc’s molecules.

We have investigated that by using AVS unit (table 1) kaolin surface activation leads to increasing of the durability of rubber-based vulcanizate to 84,3%. At the same time other characteristics are not changed. The best results were obtained when we treated the kaolin by vortex layer from 1 to 5 minutes.

Table 1

Rubber tensile strength, obtained on the base of rubber SKS-30 AKRP-N filled by activated kaolin (σр·10-5 Pа*)

Cure time under 143ºС, min

 Kaolin activation time by AVS-100, min

Kaolin activation time by ball mill, min

0

 1 2 3 4 30 60

120

20

 2,9 39,3 3,9 — — — —

—

30

 9,81 22,6 24,5 73,6 6,57 9,8 45,1 43,2
40 21,6 32,4 41,2 92,2 86,3 21,6 65,7

64,7

60

 62,8 58,9 57,9 116,0 105,0 63,8 47,1 51,0
80 55,0 50,0 76,6 92,2 55,0 29,4 29,4

55,0

* Specific elongation and residual elongation, vulcanization rigidity were not changed

 Chalk processing for 10 minutes by means of vortex later leads to increasing of structural behaviours to 51,5% (table 2). At the same time chalk processing by ball mill has no effects on the durability of the vulcanizate. Increasing of rubber`s durability filled by extenders activated in AVS is reached by means of growing of adsorptive capacity of these extenders.

It was established that by using AVS unit for kaolin processing its adsorptive capacity can be increased in 2-3 times.

 Table 2

Rubber tensile strength, obtained on the base of rubber

SKS-30 AKRP-N filled by activated chalk (σр·10-5 Pа*)

Cure time under 143ºС, min

 Chalk activation time by AVS-100, min

Chalk activation time by ball mill, min

0

 1 2 3 5 10 20 3 60 120
30 — 34,3 26,5 29,4 30,4 25,5 25,5 — —

—

40

 32,4 33,3 30,4 32,4 43,2 49,0 36,6 33,3 33,3 40,2
60 35,3 22,6 29,4 29,4 29,4 44,1 29,4 25,3 32,4

38,3

80

 27,5 27,5 22,6 30,4 34,3 36,3 35,3 21,5 28,5

30,4

From 1 to 10 minutes of treatment has continued directly-proportional dependence: adsorption capacity of kaolin increases proportional to the time of processing by AVS. Adsorption amount depends from the balance between solid and liquid phases, value of magnetic induction in the working chamber of AVS unit, form and size of ferromagnetic particles, density of vortex layer.

Adsorption capacity of kaolin increases proportional to the time of processing by AVS

Extremely strong change of extender’s adsorption capacity permits to apply AVS unit for chemical modification of kaolin and chalk.

 Filling of caoutchouc by kaolin modified at the vortex layer by means of one of universal inhibitor (DMBA) leads to cure rate increasing in 5-8 times and vulcanizate durability increasing in 2 times.

 Possibility of dry powders chemical modification is the one of the particularities of AVS unit application. Effect of rubber reinforcement and applying such extenders depends from the processing time and operational conditions of the vortex layer.

 In the rubber production process by using latex the most volume of expenditures are paid for preparation of ingredient`s dispersion, curing agent dispersion, kaolin and soot, etc. On our and foreign plants these dispersions are prepared by using ball and vibration mills. In this case grinding duration can reached 70 hours or even more.

 Application of AVS unit intensifies the process of suspension production and allows increasing the quality of products.

Table 3

Comparative data of sodium fluate stability

obtained by using AVS and ball mill

Suspension preparation time

 Maximum particles size, mcm Daily settle, %

by AVS, seconds

by Ball mill, hours

10

 — 3 35
20 — 2

34

30

 — 1 27
60 — 1

26
— 48 5

100

This table shows that by using AVS can be obtained fine and stable suspension of sodium fluate. In this case time of preparation can be reduced in 1700 times.

Our technology is implemented by different factories to produce suspension of latex technology. Productivity of this unit is 1 m3/h (fig. 1). Application of AVS units give a possibility to replace 8 vibration mills (each of these mill has a volume 400 liters), and in addition implement to the uninterrupted process which allow increasing the quality of manufactured product.

Figure 1. Application of AVS unit. Suspension production technological diagram 1 – vessels for pre-mixing of components; 2 – pump; 3 – AVS; 4 - valve for sampling; 5- tank for prepared suspension

Figure 1. Application of AVS unit. Suspension production technological diagram
1 – vessels for pre-mixing of components; 2 – pump; 3 – AVS; 4 – valve for sampling; 5- tank for prepared suspension

Table 4

Comparative data of latex sponge physical and mechanical properties

The mode of vulcanizator’s general dispersion preparation

 Physical and mechanical properties of the latex foam

volume weight,

gr/cm3

Hardness

НВ·10-5,

Pа

 Breaking strengthσр·10-5 Pа Stretch ratio, % Elastic recovery, %

Residual deformation after repeated compression, %
Ball mill

0,102

 0,198 0,338 137 88 19
0,119 0,173 0,322 133 89

28

0,106

 0,154 0,326 108 91 25
0,126 0,204 0,334 126 91

15
AVS

0,099

 0,097 0,400 176 90 1,2
0,101 0,091 0,401 180 90

0,9

0,101

 0,098 0,407 180 98 1,2
0,101 0,098 0,407 180 98

1,2

By using AVS we can obtain such mixtures of kaolin and natural latex (parotex) which is antifloating during 2 weeks.

 All prepared in AVS suspensions are very stable and antifloating. After 5 min mixing in AVS unit we obtain suspension which separate during the day only in 5 %. The same suspension but obtained by using ball mill (processing time – 4 hours), is separating during the day in 100%.

The carbon black suspension prepared by AVS is antifloating. At the same time, the same suspension prepared in ball mill is unstable and after one day is completely separated.

 The efficiency of AVS unit on latex production is obvious.

If you don’t found on this website the information you need concerning application of AVS unit, you can contact directly with the manager in charge of AVS unit by using only following email: [email protected] or skype: mg5globecore_de and we will prepare for you all required information as soon as possible

Wastewater treatment from fluorine and nitrocompound

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Fluorine-containing wastewater

 The wastewater from chemical and metallurgical enterprises which contain fluorine compounds is classified as harmful wastewater. Treatment of these wastewater from fluorine involves some problems and requires of considerable expenses and expensive reagents.

filtrovanie_vodi Water treatment from slight fluorine concentration is extremely important. These difficulties are concerned with chemical particularities of fluorine compounds. As is well-known, the substantial dissolubility has only alkali metal salts of fluoride, potassium, and ammonium.

 Regardless of the fact that all metal  fluorides (except for alkali metal fluoride) named as “marginally soluble” or “insoluble”, their solubility exceed the acceptable sanitary regulation for fluorine content in water in tens of times.

 Enterprises encounter with formidable difficulties during the treatment of wastewater from fluorine. For example, acidic water from superphosphate production plants contains up to 2,5 g/l of fluorine. The chalk or lime milk is usually used for wastewater neutralization and fluorine elimination. The water is treats by the chalk (lime milk) in the 40 m3 reactor-neutralizers which are equip by arm mixers. Hardly soluble substances such as CaF2, CaSO4, CaHPO4, Ca3(PO4)2 are precipitated in the result of chemical transformation.

Methods of wastewater treatment from fluorine

Usually enterprises are used two methods of fluorine-containing wastewater treatment:

  • Chemical method by using different reagents;
  • Sorption method

 As reagents in the chemical method of wastewater treatment can be used lime, calcium salt, magnesium salt, lead salt, basic ammonia chloride and others.

 It was observed that application of AVS unit for fluorine-containing wastewater treatment is more effective than current used equipment

Compared to other salts which can be used as a reagent, the calcium salt has more advantages. Application of calcium salt allows creating of highly coagulable sediments.

Neutralizing product (calcium fluoride) can be used as commercial product. This product is comparative marginally soluble (dissolubility is 15,6 mg/dm3)

The most effective fluorine ions precipitating agent is technological lime. Active calcium oxide containing in the lime has a significant importance. Other chemical precipitating agents leave a great quantity of its in treated wastewater.

It is established that the presence of HCO–3 and SO2-4 ions in wastewater is the cause of increasing of CaF2 sedimentation speed. To the contrary, the presence of fluorine ions in the water is the cause of decreasing of CaF2 sedimentation. Therefore it should be noted that it is impossible to well purify the wastewater from fluorine by use only reagents whose action is focused only on chemical reaction of sedimentation.

The sorption method of wastewater treatment is based on utilization of different sorbents which are acting under the chemisorption principle.

Let us look at the following wastewater characteristic and description of the technological schema of wastewater treatment of superphosphate production (chemical method of treatment is used). The wastewater contain not less than 1500 mg/dm3 of fluorine, not less than 6500 mg/dm3 of phosphates, pH is on level 2,5-3,5.

Chalk and lime is wide used by enterprises as a reagent for neutralization and treatment of fluorine-containing wastewater. Hardly soluble and insoluble compounds such as CaF2, CaHPO4, Ca3(PO4)2, SiO2 are precipitate in the result of chemical transformations

Traditional used method of treatment from fluorine

 Neutralization and treatment of fluorine-containing wastewater is made in the following way.

Pre-treatment of fluorine-containing wastewater begin in the lime-slaking apparatus in which prepare the lime milk with 1-3% active CaO content.

Installation of the AVS-100 unit enables one to provide a treatment quality below the maximum permissible concentration, reduces the consumption of reagent by 1.5-2 times, the consumption of energy by 2 times, reduces the working area by 10-15%, which results in high economic benefits

Partially defluorinated wastes with pH level 10-13 are entered in the intermediate container and then by natural flow are entered to reactors. Further treatment is carried out in the chain of reactors

Neutralized and defluorinated wastewater are entered in clarifier. The wastewater settles out in that clarifier basin. Residual fluorine content in sterilized wastewater is 50-60 mg/dm3, pH 8-12, calcium content is 2500-6000 mg/dm3. Sterilization time in reactors is 30 min.

It was investigated that if we use the chalk as a reagent for fluorine-containing wastewater treatment, we obtain the residual fluorine content in the water in 1,5-3 times and phosphate ions in 10-20 times more than if we use the lime milk. In this level of treatment we cannot discharge the defluorinated wastewater into water supply sources. Fluorine content cannot exceed 1,5-60 mg/dm3.

Application of AVS unit for fluorine-containing wastewater treatment

In this investigation we have used

  • wastewater with fluorines content 1375 mg/dm3,
  • phosphates – 4500 mg/dm3,
  • water pH – 3.3,
  • 10% concentration lime milk,
  • processing time in the AVS unit – 1-30 seconds,
  • reagent consumption – 70-120% from stoichiometric,
  • pH of defluorinatation process – 4-12.

Results of investigations are on the table 1

Table 1

 Fluorine content in wastewater after treatment by AVS unit, mg/dm3 

Lime milk consumption (active CaO), %

 Processing time, s
1 3 5 10 20

30

70 % fromstoichiometric calculation

 90,00 88,0 86,0 84,0 82,0 80,0

90 % fromstoichiometric calculation

 42,0 40,0 38,5 36,5 34,6 33,0
stoichiometric calculation 30,0 29,0 25,0 23,5 19,0

17,0

110 % fromstoichiometric calculation

 20 15 12 9 6,0

2,0

 As is known, pH of the medium has a considerable influence on the wastewater treatment process. Optimum pH of the medium leads to the optimal treatment results.

For this investigation we have used the wastewater with following content: fluorine – 1375 mg/dm3; phosphates – 4500 mg/dm3. During the treatment process we changed the wastewater pH from 4 to 12.25 by using 10% lime milk. Processing time is 1-3 seconds.

Results of investigations are on the table 2

 Table 2

The pH influence on the effectiveness of wastewater treatment after processing by AVS unit 

Residual content, mg/dm3

pH ofwastewater
4 5 5,7 6,35 7,0 8,1 9,2 10,1 11,0 11,9

12,25

F

 180,0 92,0 65,0 55,0 45,0 25,0 15,0 11,0 7,0 3,9

1,35
P2O5 1920,0 720,0 450,0 83,5 27,0 0,2 0 0 0 0

0

We have made our investigations in industrial conditions by using industrial installation of AVS unit. According to our technological schema, untreated waste from industrial shopfloor enters to the equalizing tank; lime milk (prepared in the lime carbonater extinguisher) enters into consumption tank.

Equalized waste and lime milk uninterruptedly enter the AVS unit by means of dosing pump. All these components are mixed (also take place dispergation and electromagnetic processing) and are entered to the settling tank for further defecation. Flow meters are controlling the consumption of wastewater and lime milk, pH of wastewater are controlling by pH meter.

Results of investigation are on the table 3

Table 3

The influence of lime milk consumption on the effectiveness of wastewater treatment after processing by AVS
(ferromagnetic particles: steel, d=1,6 мм, l=16 мм, m=175 g, τ=3 с)

Residual content of harmful agent, mg/dm3

 Lime milk consumption (CaO) from theoretical calculation, %
70 80 90 100 110

120

Fluorine content (F)

 98,0 60,0 35,0 20,0 10,0 0,75
Phosphates content (P2O5) 1290,0 750,0 8,4 0 0

0

Table 4

The influence of the processing by AVS on the effectiveness of wastewater treatment

Base values

 Wastewater’s values after processing on AVS unit
Wastewater

Lime milk

pH

 F, mg/dm3 P2O5, mg/dm3 CaO,% pH F, mg/dm3 P2O5, mg/dm3
3,65 350 2100 105 7,6 10

32

3,65

 700 2250 105 8,2 7,5 8
5,9 1100 3200 105 9,2 5

0

3,0

 1500 6500 105 11,5 1,2 0
3,0 1500 5100 110 11,6 1,15

0

3,95

 750 5000 110 9,3 4,5 0
3,95 750 5050 110 8,6 7,1

0

3,95

 750 5050 110 10,0 1,4

0

 It was observed that application of AVS unit for fluorine-containing wastewater treatment is more effective than current used equipment.

The productivity of AVS-100 unit is 15 m3/h, AVS-150 – up to 40 m3/h.

For reference, by using traditional methods of treatment from fluorine, neutralization process lasts 1-1.5 hours. Residual fluorine content in the water is 50-60 mg/l. Even if we will be using the chain of reactors, relative productivity cannot exceed 0.25 m3/h. As you can see – the effectiveness of AVS unit is obvious.

Besides, defluorination and insolubilizing of fluorine passes in one stage. Treated water contains 1.5 mg/dm3 of fluorine and there are no phosphates. Processing time of wastewater treatment in AVS unit is 1-3 seconds. It is rational to use the lime as a reagent.

Installation of the AVS-100 unit enables one to provide a treatment quality below the maximum permissible concentration, reduces the consumption of reagent by 1.5-2 times, the consumption of energy by 2 times, reduces the working area by 10-15%, which results in high economic benefits.

Nitrocompounds in wastewater

 AVS unit can be also implemented for water treatment from aromatic nitrocompounds. Usage of AVS allows restore nitrocompounds to amines. For this process we can recommend ferromagnetic particles made from soft carbon steel and diameter 1-1.4 mm, l/d from 12 to 16 mm.

Cyano-containing wastewater treatment machine

Articles

 Application of cyanides

Cyanides are employed in a number of chemical processes, including fumigation, case hardening of iron and steel, electroplating, and the concentration of ores.

Electrolytic metallurgy is one of the productions which have the serious influence on contamination of the environment, particularly by heavy metal ions. The main supplier of toxicants in electroplating is cleaning-purposes water. At the same time this water is the main source of wastewater.

By the reason of imperfect washing method is released the large volume of wastewater. (The known washing method requires up to 2 m3 of cleaning-purposes water for washing 1 m3 of details).

The wastewater from electroplating shops contains toxic pollutants such as cyanogen, chromium, copper, lead, acid, alkali and others.

Compared to other sewages from electroplating shops cyano-containing wastewaters are of high toxicity. The median lethal human dose of hydrocyanic acid is 1 mcg/kg (for sodium cyanide this dose is 1,8 mcg/kg, for potassium cyanide is 2,4 mcg/kg). That why all cyano-containing wastewater sterilization jobs shall be carried out with compliance of all safety requirements

 

Cyano-Containing Wastewater

The most toxic industrial wastewater is that which contain simple cyano-compound (with ions CN—), combined compounds [Cu(CN2)—], [Cu(CN3)-2], [Zn(CN4)-2]. General concentration of simple and combined cyanides is ranging from 10-15 to 150-300 mg/l.

To neutralize the high-toxic cyanides (simple cyanides, ammonocarbonous acid, compound zinc cyanide, copper, nickel, cadmium) need to apply oxidizing by reagents which contain available chlorine.

Reagent method is wide used for cyanides neutralization. For example, cyanides can be neutralized by oxidization using calcium hypochlorite Ca(OCl)2 or chloride lime CaOCl2,or gaseous chlorine.

On the enterprises the most of cyano-containing wastewater is neutralized by means of intermittently operating plants. In these plants reagentizing is made in tanks which are filling one-by-one.

Large amounts of wastewater are treated by using continuously operating plants.

The reaction proceeds in 2 stages. Stage 1 changes cyanides to cyanates (pH level is equal to 10÷11,5). In stage 2 cyanates hydrolyzed to nitrogen and carbon dioxide (pH level is equal to 7÷7,5).

State-of-the-art technology: vortex layer

Utilization of AVS unit (Intensifier of Technological Process or Magnetic Vortex Activator) gives a possibility to combine oxidization of cyanides and its decomposition to carbonate and ammonia in one stage on following conditions: reaction proceeds in alkaline medium, pH level 9÷10.

To find out more about vortex layer of ferromagnetic particles which rotated in electromagnetic fields you need only clicked this link

In the industrial implementation of the proposed method cyano-containing wastewater is fed to an equalizing reservoir from the source of their creation. Passing the reservoir these wastewater are pumping into the AVS unit. At the same time alkaline agent and oxidizer are fed to the working chamber of the unit.

The signalling indicator of cyanogen and pH-meter are controlling pH level in the AVS unit and cyanides residue level. From the AVS unit the wastewater fed to collector where they mix with neutralized wastewater obtained from other electroplating shops.

As alkaline reagent can be used lime and soda in the form of 5-10% solution. As oxidizer can be used calcium hypochlorite or sodium hypochlorite, chlorine or chloride lime. The oxidizer consumption is on level 110% from stoichiometric prediction.

In the table 1 you can see the result of investigations obtained during the testing of AVS unit on cyano-contained wastewater treatment. The productivity of this unit is 12-15 m3/h.

 Table 1

The results of cyano-containing wastewater treatment by using AVS-100

Cyan-ions: initial content, mg/l

Cyan-ion content after treatment, mg/l

8000

 0,12

2300

 0,09
4320

0,02

50

 0,02
62,4

0,0011
34,3

0,0014

It was observed that the quality of treatment is not depending from the concentration of cyan-ion in the initial wastewater.

 

Case study: successful implementation of AVS unit

 Engineers from PC GlobeCore have investigated and implemented in real electroplating shop the process flowsheet of uninterrupted and simultaneously wastewater treatment from cyanides, cyanates and hexavalent chromium compounds.

 According to this process flowsheet (figure 1) the wastewater is treated in three separate flow lines:

I – restoration hexavalent chromium Cr+6 to trivalent chromium Cr+3 in chromium-containing wastewater;

II – oxidization of cyanides to cyanates in cyano-containing wastewater;

III – simultaneous wastewater treatment after mixing neutralized chromium-containing wastewater and cyano-containing wastewater with acid-base wastewater.

To wastewater demineralization is used the gravel and sandy filter, cation and anion filters. Passing all these filters the water is fed to the filtered-water reservoir and into production.

See the figure 1.

 

Schematical diagram of cyano-containing wastewater treatmnent

Schematical diagram of cyano-containing wastewater treatmnent

Advantages of AVS unit application

Offered by us wastewater treatment methods are very effective and some of them allow reduce reagent consumption in 1.5-2 times, reduce energy consumption in 2 times and decrease working area of treatment facilities in 10-15%.

PC GlobeCore is combined of scientific research, engineering design, technical service, product development and manufacturing. You can be sure – all our products are based on breakthrough technologies and are environmentally friendly, tested by qualified engineers, fit for use and are so simple to operate that you will need only one operator.

Coal-Water Fuel production: application of AVS-100

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What is “coal-water fuel”?

 Coal-water fuel (CWSF or CWS or CWF) is a fuel which consists of fine dispersed coal particles, water and plasticizing agent. This type of fuel is widely used as an alternative to gas and black oil on different heat generating facilities. Operational economy is the main of advantages of the coal-water fuel. CW fuel has almost the same heat transfer level that the most expensive gas and black oil. Coal is cheaper in many times by comparison with gas and black oil.

Coal water fuel CWF globecore

 Characteristics of coal-water fuel are follows:

  •  rheological (viscosity, bias potential);
  • sedimentation (static and dynamic conditions homogeneity saving);
  • combustible (energy potential, combustion efficiency).

 

If you don’t found on this website the information you need concerning application of AVS unit, you can contact directly with the manager in charge of AVS unit by using only following email: [email protected] or skype: bichurina_globecore and we will prepare for you all required information as soon as possible

Properties of coal-water fuel:

  • flammability point – 800-850°С;
  • burning temperature – 950-1150°С;
  • calorific capacity – 3700-4700 kcal;
  • carbon burning degree is up to 99%.

 Coal-water fuel production technology

 CWF consists from 55-70% of fine dispersed coal particles, 30-45% of water and plasticizing agent. Water content provides the reduction of hazardous emission to the atmosphere and transforms coal to explosion- and fireproof material.

The cost of coal is in 3 times lower than the cost of heating oil. In spite of all market’s fluctuations of coal prices, the balance between prices on fuel from heating oil and coal-water fuel is on the same level.

 Coal-water fuel production process consists of three main phases:

 First phase – preliminary disintegration to the fraction size 3-12 mm. If the slurry coal of fine fraction is used as raw material you can exclude this phase.

 Second phase – wet milling in the ball mills to the fraction size

 Third phase – homogenization. On this phase is eliminated all irregularities of coal particles distribution inside of suspension, are supplemented plasticizing agents and stabilizers. On third phase CWF acquires the necessary homogeneous properties.

Phases of the coal-water fuel production process

Phases of the coal-water fuel production process

 Coal disintegration is the main goal that should be resolved during the CWF production process. Rheological properties and burning process stability are in the directly-proportional dependence from the stability of coal desintegration process with preset parameters and clear abidance of additive concentrations.

 Hammer grinders and ball mills of different types can be used for desintegration of coal, combustible schist or carbon residues.

 Among various existing methods of coal grinding, uninterrupted wet milling ball mills are the most widespread today.

 Pre-grinded to the fraction 3-6 mm coal particles are transferred to ball mills for further grinding. At the same time, water and additive are going to the ball mill. The coal is grinding in the mill to the size of fractions 0-3 mcm. After addition of all components, material is going back to the mill for further intensive grinding.

 Implementation of the Intensifier of Technological Process AVS-100 to CWF production process

 As we already noticed in our preceding articles, Intensifiers of Technological Process have a number of advantages to compare with other types of grinding equipments. These advantages are:

  • extremely, in tens and hundreds times acceleration of chemical and physical processes;
  • increasing of product yield quality;
  • decreasing of raw materials consumption;
  • decreasing of energy consumption;
  • decreasing of working space and others.

 Refer to following results of powder desintegration by AVS and different mills.

 Table 1

Type of equipment

 Power consumption, kW

Productivity,

kg/h

Fraction yield – 3 mcm, %
AVS

1,5

 > 2

50
Ball mill (wet milling)

0,5

 > 1

7-15
Ball mill (dry milling)

0,5

 > 2

1-3
Centrifugal mill

0,6

 to 10

5
Hammer mill

2,0

 > 80

5

As you can see from the table, application of AVS unit leads to considerable economy of duration of the process of material production (in 3 times), and at the same time we obtain in 5-6 times more product than if we would use ball mill with wet milling.

 It should also be noted that application of the AVS unit is the most effective for material regrinding process. Besides, vortex layer machines allow obtaining the product with the higher degree of particle fineness. Development by engineers from PC GlobeCore equipments allow intensify most of technological processes and raise production standards and exclude ball mills and vibration mills which are the sources of raised noise and dusting.

Mayonnaises and sauces production: AVS-100 application

Articles

Our scientists have designed technologies which use electromagnetic units with ferromagnetic particles for production of low-, middle- and high-calorie sauces based on the emulsion with fat content mass from 20 to 74%.

AVS-100 mayonnaise production

 Suggested technology allows obtaining the mayonnaise with the high degree of microbiological safety and high organoleptic indicators. Obtained mayonnaises are stable and not separate over the long period of time (3-12 month) depending from the concentration.

 During processing time takes place the continuous material dispersion and homogenization. Homogenization of poor-dispersion emulsion in the working chamber leads to increasing of emulsifying capacity of emulsifiers caused by optimum molecules polarization.

 Besides, application of AVS unit allows intensifying technological process thanks to exception some technological operations. As the result we can decrease the price of finished products.

Follow the link to find out more about application of AVS unit in the food industry

Coming soon: the real case study about mayonnaises production technology 

Case study: How to purify Hexavalent Chrome Wastewater

Articles

We all talk about priority pollutants, about hazardous substances and discharge to the atmosphere etc. which are dangerous for our environmental. Day by day we adopt new laws and regulations to protect our green future. So, what is that “priority pollutants”? Priority pollutants are highly toxic chemicals. The list of these chemicals is quite large and includes thousands of items but today we will speak about hexavalent chromium and methods of chromium-containing wastewater treatment.

Wastewater which contains chromium and other heavy metals is classified as high toxic wastewater. For this type of wastewater is required qualitative and effective treatment.

 Hexavalent Chrome is priority pollutant and exists in several forms. Industrial use of chromium includes in metal alloys such as stainless steel; protective coatings on metal; magnetic tapes; and pigments for paints, cement, paper, rubber, composition floor covering and other materials. Hexavalent chromium can be formed when performing “hot work” such as welding on stainless steel or melting chromium metal.

Hexavalent Chromium Compound

Hexavalent Chromium Compound

Exposure to this chemical is prevalent in different industrial applications. For this reason there exist a lot of international Standards, Directives and Acts which regulate utilization of chromium compounds and obligate to recycle chromium-containing waste. Besides, removal of chrome from wastewater is also needed to achieve the water quality level needed for reuse and recycling.

There are different chromium removal methods such as chemical precipitation, adsorption and biosorption, reverse osmosis, ion exchange, electrodialysis, photo-catalysis. We offer to use breakthrough technology – electromagnetic vortex layer with rotating ferromagnetic particles (AVS-100 or Intensifier of Technological Process).

As we already noted in our previous articles, offered method is very effective and allows reduce reagent consumption in 1.5-2 times, reduce energy consumption is 2 times and decrease working area of treatment facilities in 10-15%.

Let us remember the result of sterilization of chromium-containing wastewater.

The results of sterilization of chromium-containing wastewater by using AVS

Basic concentration value Cr6+, mg/dm3

pH process

Consumption of iron sulfate, % from stoichiometric consumption

Ferromagnetic element mass, g

Residual Cr6+ content after purification, mg/dm3

100

2

100

150

0

90

0

80

0,56

100

4

90

150

0

80

0,9

590

2

100

200

0

90

0

80

0,8

1000

2,5

100

200

0

90

0,11

80

1,1

200

7,5

100

150

0,012

200

9,0

100

150

0

90

0,05

80

0,98

750

7,5-8,5

90

200

0,1-0,01

 

As you can see from the table, the content of chromium compounds in water tends to zero after treatment by using AVS unit.

The goal of this article is to show how it works. How can we reach the complete purification of wastewater from chromium? So, let`s begin.

Typically wastewater which contains chromium compounds treated in 2 stages. First we need change hexavalent chromium Cr6+ to trivalent chromium Cr3+. As result we need obtain non-toxic materials.

Engineers from PC GlobeCore have investigated the effectiveness of AVS usage in following versions: I – sterilization of chromium-containing wastewater by reduction hexavalent chromium to trivalent chromium, II – combined neutralization of chromium-containing and acid-base wastewater with simultaneous purification from heavy metals ions.

The results of neutralization and purification from heavy metal ions are follows:

Basic metal concentration, mg/dm3

pH process

Consumption of Ca(OH)2, % from stoichiometric consumption

Ferromagnetic element mass, g

Residual metal content, mg/dm3

Fe2+;3+= 130,0

7,5

90,0

200,

Fe2+;3+ –  0

Cu2+= 50,0

Cu2+ –  0,12

Zn2+= 45,0

Zn2+ –  0,063

Cd2+= 10,0

Cd2+ –  0,07

Cr3+= 120,0

Cr3+ –  0

Fe2+;3+= 170,0

8,5

100,0

150

Fe2+;3+ –  0

Cu2+= 40,0

Cu2+ –  0,018

Zn2+= 28,0

Zn2+ –  0

Cd2+= 5,5

Cd2+ –  0,011

Cr3+= 100,0

Cr3+ –  0

Fe2+;3+= 250,0

8,7

100,0

200

Fe2+;3+ –  0

Cu2+= 65,0

Cu2+ –  trace

Zn2+= 35,0

Zn2+ –  trace

Cd2+= 2505

Cd2+ –  0

Cr3+= 350,0

Cr3+ –  0

 

On the basis of performed investigations and production experiments of AVS application for wastewater treatment, we offered and implemented manufacturing schemes of wastewater treatment on different treatment facilities.

On the figure 1 is shown the diagram of simultaneous treatment of chromium-containing and acid-base wastewater.

Figure 1. The diagram of simultaneous treatment of chromium-containing and acid-base wastewater: 1 - mixing cylinder; 2 – tank for reducing agent (solution FeSO4); 3 – tank for Na2CO3 solution preparation; 4, 7, 11 – pumps; 5 - tank for reducing agent; 6 – tank for sulphuric acid; 8 – AVS unit, 9, 10 – settling tank; 12 - vacuum filter; 13 - dosing unit; 14 - flow rate meter; 15 – reagent consumption control valve; 16 - sampling unit; 17 – pH-meter

Figure 1. The diagram of simultaneous treatment of chromium-containing and acid-base wastewater:
1 – mixing cylinder; 2 – tank for reducing agent (solution FeSO4); 3 – tank for Na2CO3 solution preparation; 4, 7, 11 – pumps; 5 – tank for reducing agent; 6 – tank for sulphuric acid; 8 – AVS unit, 9, 10 – settling tank; 12 – vacuum filter; 13 – dosing unit; 14 – flow rate meter; 15 – reagent consumption control valve; 16 – sampling unit; 17 – pH-meter

According to this diagram, sewage from shopfloors is alternately entering into two mixing cylinders. When the first of these cylinders is filled by sewage and this sewage is neutralized, to cylinder is fed the acid (in order to acidize the sewage to 2-3 pH level) and is fed reducing agent (sodium bisulfite). After 5-10 minutes mixing this sewage is fed into AVS unit. (Before adding the sewage into AVS, this sewage was filled by Na2CO3 to obtain the value of pH level at elevation 7,5-9). During couple seconds of processing in AVS unit can be achieved complete and effective wastewater treatment by reagents. During this time is completed restoration of Cr6+ to Cr3+ and formation of Cr3+ hydroxide and other heavy metals. As reducing agent can be used FeSO4 (ferrous sulfate).

In this case chromium restoration can be provided in each of acid and base medium. The wastewater with metal hydroxides (after processing in AVS unit) enters the settling tank for defecation and then – the sewerage or the water recycling (to the shopfloors for engineering purpose). The sludge from settling tank is dewatered by vacuum filters.

In conclusion it should be noted that application of AVS unit allows obtaining the quality of treatment lower than maximum permissible concentration, reduce reagent consumption in 1,5-2 times, reduce energy consumption in 2 times and decrease working area of treatment facilities in 10-15%.

We all talk about priority pollutants, about hazardous substances and discharge to the atmosphere etc. which are dangerous for our environmental. Day by day we adopt new laws and regulations to protect our green future. So, what is that “priority pollutants”? Priority pollutants are highly toxic chemicals. The list of these chemicals is quite large and includes thousands of items but today we will speak about hexavalent chromium and methods of chromium-containing wastewater treatment.

 Hexavalent Chrome is priority pollutant and exists in several forms. Industrial use of chromium includes in metal alloys such as stainless steel; protective coatings on metal; magnetic tapes; and pigments for paints, cement, paper, rubber, composition floor covering and other materials. Hexavalent chromium can be formed when performing “hot work” such as welding on stainless steel or melting chromium metal.

Hexavalent Chromium Compound

Hexavalent Chromium Compound

Exposure to this chemical is prevalent in different industrial applications. For this reason there exist a lot of international Standards, Directives and Acts which regulate utilization of chromium compounds and obligate to recycle chromium-containing waste. Besides, removal of chrome from wastewater is also needed to achieve the water quality level needed for reuse and recycling.

 Wastewater which contains chromium and other heavy metals is classified as high toxic wastewater. For this type of wastewater is required qualitative and effective treatment.

There are different chromium removal methods such as chemical precipitation, adsorption and biosorption, reverse osmosis, ion exchange, electrodialysis, photo-catalysis. We offer to use breakthrough technology – electromagnetic vortex layer with rotating ferromagnetic particles (AVS-100 or Intensifier of Technological Process).

As we already noted in our previous articles, offered method is very effective and allows reduce reagent consumption in 1.5-2 times, reduce energy consumption is 2 times and decrease working area of treatment facilities in 10-15%.

Let us remember the result of sterilization of chromium-containing wastewater.

The results of sterilization of chromium-containing wastewater by using AVS

Basic concentration value Cr6+, mg/dm3

pH process

Consumption of iron sulfate, % from stoichiometric consumption

Ferromagnetic element mass, g

Residual Cr6+ content after purification, mg/dm3

100

2

100

150

0

90

0

80

0,56

100

4

90

150

0

80

0,9

590

2

100

200

0

90

0

80

0,8

1000

2,5

100

200

0

90

0,11

80

1,1

200

7,5

100

150

0,012

200

9,0

100

150

0

90

0,05

80

0,98

750

7,5-8,5

90

200

0,1-0,01

 

As you can see from the table, the content of chromium compounds in water tends to zero after treatment by using AVS unit.

The goal of this article is to show how it works. How can we reach the complete purification of wastewater from chromium? So, let`s begin.

Typically wastewater which contains chromium compounds treated in 2 stages. First we need change hexavalent chromium Cr6+ to trivalent chromium Cr3+. As result we need obtain non-toxic materials.

Engineers from PC GlobeCore have investigated the effectiveness of AVS usage in following versions: I – sterilization of chromium-containing wastewater by reduction hexavalent chromium to trivalent chromium, II – combined neutralization of chromium-containing and acid-base wastewater with simultaneous purification from heavy metals ions.

The results of neutralization and purification from heavy metal ions are follows:

Basic metal concentration, mg/dm3

pH process

Consumption of Ca(OH)2, % from stoichiometric consumption

Ferromagnetic element mass, g

Residual metal content, mg/dm3

Fe2+;3+= 130,0

7,5

90,0

200,

Fe2+;3+ –  0

Cu2+= 50,0

Cu2+ –  0,12

Zn2+= 45,0

Zn2+ –  0,063

Cd2+= 10,0

Cd2+ –  0,07

Cr3+= 120,0

Cr3+ –  0

Fe2+;3+= 170,0

8,5

100,0

150

Fe2+;3+ –  0

Cu2+= 40,0

Cu2+ –  0,018

Zn2+= 28,0

Zn2+ –  0

Cd2+= 5,5

Cd2+ –  0,011

Cr3+= 100,0

Cr3+ –  0

Fe2+;3+= 250,0

8,7

100,0

200

Fe2+;3+ –  0

Cu2+= 65,0

Cu2+ –  trace

Zn2+= 35,0

Zn2+ –  trace

Cd2+= 2505

Cd2+ –  0

Cr3+= 350,0

Cr3+ –  0

 

On the basis of performed investigations and production experiments of AVS application for wastewater treatment, we offered and implemented manufacturing schemes of wastewater treatment on different treatment facilities.

On the figure 1 is shown the diagram of simultaneous treatment of chromium-containing and acid-base wastewater.

Figure 1. The diagram of simultaneous treatment of chromium-containing and acid-base wastewater: 1 - mixing cylinder; 2 – tank for reducing agent (solution FeSO4); 3 – tank for Na2CO3 solution preparation; 4, 7, 11 – pumps; 5 - tank for reducing agent; 6 – tank for sulphuric acid; 8 – AVS unit, 9, 10 – settling tank; 12 - vacuum filter; 13 - dosing unit; 14 - flow rate meter; 15 – reagent consumption control valve; 16 - sampling unit; 17 – pH-meter

Figure 1. The diagram of simultaneous treatment of chromium-containing and acid-base wastewater:
1 – mixing cylinder; 2 – tank for reducing agent (solution FeSO4); 3 – tank for Na2CO3 solution preparation; 4, 7, 11 – pumps; 5 – tank for reducing agent; 6 – tank for sulphuric acid; 8 – AVS unit, 9, 10 – settling tank; 12 – vacuum filter; 13 – dosing unit; 14 – flow rate meter; 15 – reagent consumption control valve; 16 – sampling unit; 17 – pH-meter

According to this diagram, sewage from shopfloors is alternately entering into two mixing cylinders. When the first of these cylinders is filled by sewage and this sewage is neutralized, to cylinder is fed the acid (in order to acidize the sewage to 2-3 pH level) and is fed reducing agent (sodium bisulfite). After 5-10 minutes mixing this sewage is fed into AVS unit. (Before adding the sewage into AVS, this sewage was filled by Na2CO3 to obtain the value of pH level at elevation 7,5-9). During couple seconds of processing in AVS unit can be achieved complete and effective wastewater treatment by reagents. During this time is completed restoration of Cr6+ to Cr3+ and formation of Cr3+ hydroxide and other heavy metals. As reducing agent can be used FeSO4 (ferrous sulfate).

In this case chromium restoration can be provided in each of acid and base medium. The wastewater with metal hydroxides (after processing in AVS unit) enters the settling tank for defecation and then – the sewerage or the water recycling (to the shopfloors for engineering purpose). The sludge from settling tank is dewatered by vacuum filters.

In conclusion it should be noted that application of AVS unit allows obtaining the quality of treatment lower than maximum permissible concentration, reduce reagent consumption in 1,5-2 times, reduce energy consumption in 2 times and decrease working area of treatment facilities in 10-15%.