Innovative Investment Project
We have developed a unique techniques that enables organic retention and removal of toxic metal ions from the water. Our research facility has already achieved great success in this field and has filed the first patents.
In addition, we are currently researching and developing a novel technology for extracting fresh water from seawater (salt water) in order to prevent the water shortage that threatens in the future.
If the wastewater contains water-insoluble substances or colloids, effective wastewater treatment can be achieved by sedimentation, filtration or centrifugal separation, for example. Flotation, in which particles adhere to fine air bubbles through adhesive forces, is also used as part of the physical treatment process, depending on the composition of the wastewater. Reliable mechanical pre-treatment is particularly important in the treatment of sanitary wastewater in order to protect the wastewater technology of the subsequent treatment stages from damage.
In chemical wastewater treatment, the targeted addition of certain substances causes the pollutants dissolved in the wastewater to be more easily separated. During precipitation, for example, a previously dissolved substance is converted into a less soluble substance that can be filtered out of the liquid. Other possibilities for removing pollutants are ion exchange, flocculation or UV ozone treatment.
Wastewater treatment with membrane technology
- Microfiltration
- Ultrafiltration
- Nanofiltration
- Reverse Osmosis
Rakes and sieves are used to remove disturbing solids from the water. This mechanical process is used, for example, to separate diapers and hair as well as wet wipes and hygiene tissues from the wastewater stream. Before the industrial waste water is cleaned, screening systems also collect textile fibers, paper labels, plastic residues as well as production residues such as potato peelings and other peeling residues.
Coarse or fine screens are used depending on the application. They clean the water with the help of parallel bars. Screens, on the other hand, have grids, holes and meshes. With different opening sizes from coarse (> 20 mm) to micro sieve (< 0.05 mm) they separate solids from coarse civilization waste to sand and sludge particles from the wastewater stream.
The mechanical pre-treatment is of great importance in the treatment of sanitary wastewater. Fibers contained in the wastewater, especially the extremely tear-resistant textile fibers from wet wipes and fleeces, are a particular challenge here. They tend to clog and can therefore cause blockages and enormous damage to pumps and agitators.
The specialists select together with you suitable drum screens or self-cleaning rakes to avoid damages of your sewage treatment technology and thus unnecessary maintenance work from the beginning and to save costs.
Filtration is used to separate solids from liquids. For this purpose, the mixture to be separated passes through a filter; in the simplest case, this can consist of paper. For technical applications, filters made of textile fabric or metal are usually used. Sand filters, drum screens and cloth filters are also frequently used.
With the help of the filter systems, inorganic and organic suspended matter, sand and dust can be removed from the water. In waste water technology, this mechanical separation process is used, among other things, to dewater sludge in filter presses. Filtration is also used in the treatment of industrial and drinking water from surface water, usually in multi-stage processes.
Membrane filtration is also a mechanical separation process. In this case a membrane serves as filter medium. This method is usually used to separate very small components.
With membrane filtration, dissolved and undissolved substances can be separated and concentrated from the wastewater. The separation takes place under pressure; the membrane retains particles or molecules with a certain pore size from a certain size onwards. The different processes are used for water treatment, wastewater purification, process water recycling and for the concentration of valuable substances for recovery.
Microfiltration is used to separate particles as well as bacteria and yeasts. It is therefore used for cold sterilization and for the separation of oil-water emulsions, among other things.
Ultrafiltration is an important process for drinking water and waste water treatment. It is used to separate particles, microorganisms, proteins and turbidity substances from the water, among other things in the membrane bioreactor (MBR). Ultrafiltration is used, for example, to clean the circulating water in swimming pools. Since the formation of clogging deposits on the membrane can now be avoided, ultrafiltration is increasingly being added to existing wastewater treatment plants as a so-called polishing step. When retrofitting older, classic wastewater treatment plants, ultrafiltration can be used directly in or after the aeration tank to replace downstream treatment steps or to increase the purification performance of the biological wastewater treatment.
Nanofiltration is capable of retaining viruses, heavy metal ions, large molecules and very small particles. This process is used for water softening and in drinking water treatment.
Reverse osmosis is an important process step, for example, in the concentration of landfill waste water, in drinking water treatment in rural areas that are not connected to the mains, in seawater desalination or in the decalcification of boiler water in power plants. The concentration of substances dissolved in liquids is increased through a semi-permeable membrane by using pressure to reverse the process of osmosis: If the pressure is higher than the respective osmotic pressure, the molecules of the solvent diffuse to the side of the membrane where dissolved substances are already less concentrated. This process is also used to obtain ultrapure water.
In flotation, dispersed or suspended substances from liquids are transported to the surface with the aid of small gas bubbles and removed there with a scraper device. Flotation processes are used in wastewater treatment to separate oils, fats and finely suspended solids such as suspended solids.
The smaller the microbubbles, the better the particles or droplets are deposited. For this reason, Dissolved Air Flotation (DAF) is often used in wastewater technology. It has proven itself due to its economy and efficiency. Flotation processes can also be supported by the use of auxiliary materials such as collectors, foamers, regulators or pushers.
In sedimentation, gravity is used to separate solid particles in sedimentation tanks. A sedimentation tank is a flat and almost flow-free tank especially for sedimentation processes. The solid particles settle to the bottom.
Sedimentation processes are widely used in wastewater treatment: Already in the primary sedimentation tank undissolved substances settle. They form the primary sludge, which is then thickened and anaerobically converted in the so-called digestion tower. This produces digested sludge and digester gas, which can be used in purified form like biogas to cover the energy demand. Aerobically produced sewage sludge is also introduced into the digestion tower after it has been separated from the waste water by sedimentation in the secondary clarifier. Particles heavier than water can also be separated from the liquid with the help of grit chambers or sludge collectors.
Neutralization is used in waste water technology to adjust the pH value. Especially after processes like precipitation and flocculation as well as for the neutralization of industrial waste water, acids or bases are added as required.
Redox reactions are widely used in chemical waste water treatment and drinking water purification. For example, radical oxidation with ozone and hydrogen peroxide is used to efficiently remove chlorinated hydrocarbons and pesticides from drinking water.
Oxidation processes are also used in wastewater treatment to remove compounds that are difficult to biodegrade. Photochemical purification is particularly effective, in which hydroxyl radicals are generated from hydrogen peroxide or from ozone in the presence of water using UV light. These so-called Advanced Oxidation Processes (AOP) are also used to destroy active pharmaceutical ingredients such as antibiotics, cytostatics or hormones and other anthropogenic trace substances.
Ozone is also used to oxidize iron and manganese in well water. Reduction processes, on the other hand, are necessary for the conversion of heavy metal ions, for example, into poorly soluble sulfides.
Adsorption is the accumulation of substances on the surface of a solid. This is typically a physical process in which molecules adhere to the interface by van der Waals forces. If substances are bound to the surface of a solid by chemical bonds, this is called chemisorption. In contrast to adsorption, chemisorption is often not reversible.
In wastewater treatment, activated carbons are used to capture dissolved water constituents that could not be sufficiently removed by cheaper processes such as the methods of biological wastewater treatment, precipitation and flocculation. Thus, dyes from textile dyeing plants can often only be completely removed from the waste water by adsorption on activated carbon. Anthropogenic trace substances, such as drug residues, and polar organic substances, such as adsorbable organically bound halogens AOX, also bind to the activated carbon.
Doped activated carbon can also be used to remove arsenic and heavy metals. Iron hydroxide granules are also ideally suited for removing the toxic semi-metal arsenic from drinking water, contaminated ground water and polluted industrial waste water. The iron hydroxide ultimately reacts with the arsenate ions to form iron arsenate. This process is both very efficient and cost-effective.
Precipitation is a chemical process by which a previously dissolved substance is separated from a solution. A common method is the precipitation reaction by adding suitable substances. In this way, heavy metals can be precipitated by conversion into poorly soluble metal hydroxides. Sometimes precipitation as carbonate or sulfide may also be necessary.
Anions can often be precipitated as calcium, iron or aluminum salts. Thus, the separation of fluoride ions is carried out by a precipitation reaction with milk of lime. In the course of wastewater treatment in the sewage plant, the phosphate concentration is lowered by adding salts such as iron(II) sulfate, iron chloride or aluminum chloride. This so-called phosphate precipitation can either be integrated as simultaneous precipitation in the biological clarification stage or can be connected downstream as a separate process stage.
Flocculation creates the conditions for removing even the finest particles from the water, which are present in suspension or in the form of colloidal solutions. With the same surface charges, for example, these smallest solid particles cannot combine to form larger agglomerates due to mutual electrical repulsion.
With the help of suitable chemicals, the so-called flocculants and flocculation aids, the agglomeration of such particles can be achieved. This results in macro-flocs which sediment. Flocculation is used to improve the sedimentation properties and dewatering of sewage sludge. If iron and aluminium salts are used as flocculants, phosphate precipitation can take place simultaneously.
Ion exchangers are materials with which ions in a solution can be replaced by other ions. For example, a cation exchanger is used to exchange calcium ions for sodium ions. When this ion exchanger is exhausted, i.e. completely saturated with calcium ions, it must be regenerated.
This process works because the higher the charge of an ion exchanger, the more ions are bound to it. The stronger binding ion displaces the weaker binding one.
Ion exchangers are suitable for the targeted removal of heavy metals and anions. They are therefore often used as "police filters" after precipitation/flocculation. They are also used for softening, salination and desalination of water. This is particularly important in the semiconductor industry, where they are used to produce extremely clean demineralized water, the so-called ultrapure water.
Ion exchangers are also used for the treatment of waste water from galvanic coating plants containing metal ions or for the purification of waste water containing phenols from the chemical industry. Both the metal ions and the phenols can be recovered.
Our researchers have created a chemical derivative by oxidation that can be applied to a substrate like an ink, creating a thin membrane. The holes in the membrane are no larger than one nanometer - in other words, they are a million times smaller than one millimeter.
The result: water penetrates through the membrane. Salt does not. The development is almost completely finished. In the next stage, machines must be developed that can desalinate entire masses of water and thus supply entire countries with drinking water.
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Our developments will change the world. With your investment you can improve and accelerate the development.
Stone Golden Ltd. - an innovative company