Sorption method for cleaning wastewater. Modern high-tech technologies

ESSAY

Sorption and ion exchange methods of wastewater purification, the range of concentrations of pollutants for the adsorption method are discussed. A number of sorbents are discussed. Regeneration processes.

Keywords:

Application

It is known that adsorption Methods are used in water treatment, in water treatment for deep wastewater purification from dissolved organic substances after biological purification, in local installations purification of stockIf the concentration of these substances in water is small and they do not bologically decompose or are strongly oxic and in hydrometallurgy. Upper Application Limit sorption Methods 1000 mg / l. Lower limit of use of 5 mg / l. The use of local installations is considered advisable if the substance is good adsorbedwith a small specific consumption adsorbent.And the concentration of the pollutant is approaching the upper limit. Sorption treatment systems operate at low concentrations of the pollutant (up to 100 mg / l), high linear flow rate and high distribution coefficients sorbat in sorbent Compared to mortar. Apply sorbiationfor neutralization wastewater from phenols, herbicides, pesticides, aromatic nitro compounds, surfactants, dyes, heavy metals, etc. The advantage of the method is high efficiency, opportunity wastewater purification containing a number of toxic substances, as well as to extract and recovery these substances. There are a wide variety on the market sorbents. Adsorption sewage treatment may be regenerative, with a removal of a substance from adsorbent. and its disposal. It can be destructive at which extracted from waste water Substances are destroyed along with the adsorbent. Efficiency adsorption cleaning of stock reaches 80-95% and depends on chemical nature adsorbent., the values \u200b\u200bof the adsorption surface and its availability, from chemical structure The pollutant substance and the chemical form of its location in the environment. We apply mainly regenerative sorption purification of stock, with original regeneration methods and eluting media.

Adsorbents

As sorbents Use the very following different substances: Active coals, synthetic sorbents And some waste production (ash, slags, layers, sawdust, etc.). Mineral sorbents - clay, silica gel, alumino and metal hydroxides are used for adsorption of various substances from wastewater relatively rare, since the energy of interaction with water molecules is large and sometimes exceeds energy adsorption. Most versatile out adsorbents Active coals are, however, they must have a certain complex of properties. Active coals should weakly interact with water molecules and good - with organic substances, be relatively large (with an effective radius of adsorption pores in the range of 0.8-5.0 them, or 8-50 a) so that their surface is available for organic molecules . With a small contact time with sew water they should have a high adsorption Capacity high Selectivity and low restraint with regeneration. Subject to observance last conditions The cost of reagents for coal regeneration will be small. Coals must be mechanically durable, quickly wedged with a drain, have a monodissens of the granulometric composition. In the process Purification of stock A fine-grained adsorbents with particles of 0.25-0.5 mm particles and highly dispersed coals with particles of less than 40 microns are used. Coals must have low catalytic activity in relation to oxidation reactions, condensation, etc., as some organic substanceslocated in wastewaterare able to oxidize and dumping when passing stream. These processes are accelerated by catalysts. Daily substances are clogged adsorbentwhat makes it difficult for its low-temperature regeneration. Finally, they must have a low cost, not to reduce the adsorption capacity after regeneration and provide a large number of cycles of work. Virtually any carbon-containing material can be raw materials for active coal: coal, wood, polymers, nutritional, pulp and paper and other industries. The adsorption capacity of active coal is a consequence of a highly developed surface and porosity. Carbochrome and carboopags are granular carbon sorbents. They relate to broader materials, their specific surface area from 10 to 100 m 2 / g (A.V.Kislev, DPPoshkus, Ya.I.Yashin Molecular bases of adsorption chromatography.-M.: Chemistry, 1980). They have a high sorption capacity, mechanically durable, but so expensive that they are used only in chromatography. IN wastewater treatment Coals are still used, although much more efficient materials are created.

Basics of the adsorption process

Substances well adsorbed from wastewater active coals, have a convex isotherm adsorption, and poorly adsorbing - concave. Isotherm of adsorption of a substance located in waste waterDetermine the experimental way. If in waste water There are several components, to determine the possibility of their joint adsorption for each substance, the value of standard differential free energy is found and determine the difference between the maximum and minimum value. If the difference is more than some critical value, the joint adsorption of all components is possible. If this condition is not respected, then cleaning is carried out sequentially into several steps. Process rate adsorption depends on the concentration, nature and structure dissolved in stock substances, water temperature, type and properties a adsorbent.. In the general case process adsorption consists of three stages: transfer of substance from wastewater To the surface of grains adsorbent. (external diffusion region), actually adsorption process, Movement of the substance inside grains adsorbent. (intradiffusion region). It is believed that the speed itself adsorption Great and does not limit the overall speed of the process. Consequently, the limiting stage may be an external or internal diffusion. In some cases, the process is limited by both these stages. In the outer diffusion region, the mass transfer rate is mainly determined by the intensity of the flow turbulence, which primarily depends on the fluid rate. In the intradiffusion region, the intensity of mass transfer depends on the type and size of the pores of the adsorbent, from the forms and size of its grains, on the size of the molecules of adsorbing substances, from the mass conductor coefficient. Given all these circumstances, determine the conditions under which adsorption cleaning waste Waters comes with optimal speed. The process is advisable to conduct with such hydrodynamic modes so that it is limited in the intradiffusion region, the resistance of which can be reduced by changing the structure of the adsorbent and reducing the size of the grain. For indicative calculations, it is recommended to take the following values \u200b\u200bof the speed and diameter of the grain. adsorbent.: speed of 1.8 m / h and particle size is 2.5 mm. At values \u200b\u200bless than the specified, the process is limited by the outer diffusion region, at large values \u200b\u200b- in intradiffusion.

Adsorption Installations

The process of adsorption sea water purification lead with intensive stirring adsorbent. With water, when filtering water through a layer adsorbent. or in a fluidized bed at the installations of periodic and continuous action. With mixing adsorbent. SO sew water Active coal in the form of particles is 0.1 mm and less. The process is carried out in one or more steps. 15-20% coal suspension are supplied from above, and below sew water. Excess coal is removed into the collection.

We produce and supply alpha-7xc-7xc sorption modules, as well as various pressure filters. Non-perm adsorber Have a comfortable upper load, which is an advantage with a strong pollution of the drain, when it is necessary to carry out deep regeneration of the sorbent.

Adsorbent Regeneration

The most important stage of the process hell sorption cleaning is the regeneration of active coal. The adsorbed substances from coal are removed by desorption with a saturated or superheated water vapor or heated inert gas. The temperature of the superheated steam at the same time (with an overpressure of 0.3-0.6 MPa) is 200-300 ° C, and inert: gases 120-140 ° C. Steam consumption during distillation of volatile substances is 2.5-3 kg per 1 kg of distilled substance, for high-boiling 12.5-30 kg. After desorption, the pair condenses and the substance is removed from condensate. For regeneration of coal, extraction (liquid phase desorption) with organic low-boiling and easily distilling with water ferry solvents can be used. With regeneration with organic solvents (methanol, benzene, toluene, dichloroethane, etc.), the process is carried out during or without heating. At the end of the desorption, the residue solvents from coal are removed with a sharp ferry or inert gas. For desorption Adsorbed weak organic electrolytes are translated into a dissociated form. At the same time, the ions go into the solution enclosed in the pores of coal, from where they wash them hot water, acid solution (for removing organic bases) or alkalis solution (for acid removal). At the same time, due to ionization, the sorbate molecule is charged and due to this are desorbed. In some cases, the adsorbed substance is regenerated by chemical transformation to another substance that is easier extracted from the adsorbent. In the case when adsorbed substances do not represent values, conduct destructive regeneration by chemical reagents (chlorine oxidation, ozone or thermally). Thermal regeneration is carried out in the furnaces of various structures at a temperature of 700-800 ° C in an oxygen-free medium. Regeneration leads a mixture of gas combustion products or liquid fuel and water vapor. It is associated with loss of carbon part sorbent (15-20%). Designed biological methods Regeneration of coal at which adsorbed substances are biochemically oxidized. This method of regeneration significantly extends the use of the sorbent, but lengthy and time consuming.

Examples adsorption Cleaning

Adsorption sewage treatment From nitroproducts, the content of which in water is in the range of 1400 mg / l, produce coals of the CAD to the residual content of their no more than -20 mg / l. Coal is regenerated by solvents (benzene, methanol, ethanol, methylene chloride). The solvent and nitroducts are separated by distillation. The residues of the solvent from coal remove with a sharp steam. For the extraction of phenols from wastewater, active coals of various brands are used. High absorption capacity has selective high-barreled minorial coals with a high porous structure, as well as the corners of IGM-90 brands, CAD (iodine), Bau, OU (dry), AG-3, AP-3. The degree of extraction of phenols by these coal varies from 50 to 99%. The sorption container decreases with an increase in the middle of the medium and at pH \u003d 9 is 10-15%. At a concentration of phenols up to 0.5 g / l, the adsorption value corresponds to the exponential addiction. The regeneration of coals is carried out in a thermal method in multi-end furnaces or furnaces with a boiling layer at a temperature of 870-930 ° C. At the same time, 10-15% of the adsorbent is lost. In the regeneration of coal with solvents (ethyl ether, benzene, alkali), regeneration reaches 85, 70 and 37%, respectively. It is possible to remove phenols from coal and ammonia water.

In some cases wastewater cleaning From phenols it is possible to carry out with the use of such sorbents as diatomites, tremble, slags, coke, peat, silica gel, quartz sand, ceramzite, ceramiculitis, etc. However adsorption The container of them is small. For silica gel, it is 30%, and for half a bed just 6%. Practically complete wastewater disfenalization is achieved using iron sulfate, modified by polyacrylamide and carboxymethyl cellulose as a sorbent. Lignin, impregnated with chlorine gland, is able to sorbitize up to 92% -fenol at the concentration of the last 3-9 mg / l. Active coals in the form of powders are applicable to remove chlororganic pesticides from water to their residual concentration of 10 -B. mg / l. The greatest containers have coals of OU-A, KAD, BAU, CT. The adsorption treatment of wastewater production of insecticidal preparations "Prima-7" and "dichlofos" from toxic components to extremely permissible concentrations is achieved at a specific consumption of coal AG-3 -0.06 g / l and filtering speed 2 m / h. To remove small amounts of surfactants from wastewater (no more than 100-200 mg / l), the adsorption purification of the AG-5 and Bau is used, the adsorption capacity of which is at the OD-10 15%. In addition, an active anthracite can be used (capacity - 2%) and natural sorbents (peat, clay, brown coals, etc.), as well as slag and ash, the sorption capacity of which depends on the pH of the medium. For example, anionic surfactants are sorbed by slag best in a neutral environment. The most efficient process proceeds in case the surfactant is in the solution in the form of a micelle. Process cleaningthey are carried out in filtration columns with a fixed layer of coal, passing water from the bottom up at a speed of 2-6 m / s. Previously, suspended substances should be removed from the water. Coal regeneration is carried out by hot water, aqueous solutions of acids (to remove cation-exchange surfactants) or alkalis (to remove anionactive surfactants), as well as organic liquids dissolving surfactants. For adsorption of surfactants, precipitation of aluminum and iron hydroxides can be used, copper sulfides and phosphates of calcium, which are formed when coagulant to wastewater is added. Freckled hydroxides have a large-pore structure. The specific surface of their pores is 100-400 m 2 / g. When studying the adsorption process of OP-7, aluminum hydroxide is found that isotherms have a complex curve consisting of three sections. With an increase in the pH of the wastewater sorption op-7 adsorbent decreases. The adsorption also affects the content of electrolyte wastewater and the mass of the sorbent. The introduction of polyacrylalamum into the waste water intensifies the process of falling out of hydroxide flakes and increases their adsorbionic container. The advantage of carbon sorbents is a relatively low cost. The lack of them consists in a tendency to mechanical destruction, oxidation. Coals are poorly sorbed by polar substances. Granulated carbon sorbents have a high cost. Low density and hydrophobicity greatly complicates the sorbent laying in the layer, as a result of which the columns with them have a low number of theoretical plates. IN last years Sorbents appeared, in which high sorption properties are combined, low cost, high density and ability to sorbit polar substances. In particular, they belong to the ODM sorbent.Sorbent ODM - Granulated filter material of terracotta color (light orange) made of natural raw materials, with the content of the main components: SiO2 to 84%; FE. 2 O 3 no more than 3.2%; Al 2 O 3 , MGO, CAO - 8%. The toxicity of the aqueous exhaust is satisfying sanitary requirements.

The average bulk mass, kg / m 3: 680-720.

Specific surface, m 2 / g: 120-180.

Full sorption tank, g / g: 1.3.

Moisture capacity,%: 80-95.

Conditional mechanical strength,%: 0.85.

Grinding,%: 0.22.

Abrasability,%: 0.09.

Total porosity,%: 80.

Internal pore volume, cm 3 / g: up to 0.6.

Refractory, OS: 1400.

Oilheads for petroleum products, mg / g: 900.

Ion exchange capacity, milking / g: to 1.2 for dissolved salts Cr, Ni, and other heavy metals.

Ion exchange capacity for Cao, MgO, mg / g: up to 950.

The distribution coefficient of radionuclides is 103-104.

The toxicity of the aqueous exhaust is satisfying hygienic requirements.

The specific effectiveness of natural radionuclides is no more, BC / kg: 80.

Scope: PH 5-10.

Porosity intercontrolle,%: 42-52.

Sorption capacity in static conditions, mg / g (dynamic activity, mg / g):

Aluminum - one 1.5 (700);

Iron - up to 9.0 (850);

Petroleum products - up to 9.0 (170);

Phenol - up to 16.0.

The material is chemically racks, mechanically stable, wetted with water and can be regenerated by calcining to a temperature of 600 0 C.

Many years of experience sorbent ODM in the complexes of wastewater treatment of Alfa confirmed consistently high sorption qualities of the sorbent. The sorbent was successfully delivered from the Urals to Chukotka, it withstands the impact of low temperatures. Increased sorption properties are manifested when applied to electrochemical degradation in electrochemical destruction in electrochemical modules.

Besides purification of stock, sorbent.successfully operated on water treatment, in particular on the Irkutsk brewery, and in harsh conditions, on hot water.

Given the difficult situation with drinking water For most of Russia, such material is relevant for water treatment. Preferred scope - water treatment of natural waters containing iron impurities, moderate concentrations of stiffeners and suspension salts.

For proper use sorbentsyou need to know their properties, own know-how on applying them for a specific type of wastewater. We studied sorbents in our laboratory, gained experience in applying them during commissioning and experienced exploitation. Therefore, we are able to exercise sorting wastewater in a short time and high quality.

On issues of equipment of treatment facilities with sorbents, the conditions of their operation can be consulted with the author of this publication by e-mail [Email Protected]

To implement the process of sorption cleaning, we apply both pressure and free-free adsorbers filters, performed in plastic, stainlessly. With the skillful overseas of those and others, their advantages are fully manifested. In particular, the non-pressure alpha-8xca adsorbers with a transparent top cover make it possible to observe the sorption process, select the adsorbent samples, to quickly extract and rinse the sorbent and they are preferable at high specific loads on the filter material. Whereas the pressure adsorbers operate at low concentrations automatically and provide greater sorption efficiency.

In addition to standard sorbents, we have the opportunity to produce special sorbents, highly selective, configured to a certain sorbate

Materials published on the site are protected according to the Copyright Act. The Law of the Russian Federation of July 9, 1993 N 5351-I "On Copyright and Related Rights" (as amended July 19, 1995, July 20, 2004) and cannot be used without permission of the author.

Keywords: Recruitment System, Claiming, Sorbent, Sorption, Purification, Ionitals, Cathionics, Anionite, Ampholit, Sorbate, Regeneration

Introduction ........................................................................ .... 3

Methods of solid waters ............................................. ... 4

Sorption methods of cleaning ............................................. 6

CONCLUSION .......................................................................1/1/1/1

List of references ............................................................ 13

Introduction

Waste water is a favorable medium for the development of various microorganisms, including pathogenic, which are pathogens and distributors of infectious diseases. Polluting the environment, wastewater simultaneously create conditions for the occurrence of various human diseases and epidemics. In addition, sewers may contain toxic substances (acids, alkalis, salts, etc.), which can cause poisoning of living organisms and the death of plants. Wastewater should be removed from settlements, cities and industrial enterprises. Before discharged to the reservoirs, they should be purified, otherwise surface reservoirs and underground water sources will be contaminated and the use of them for water supply and household purposes will be impossible.

In rivers and other reservoirs there is a natural process of self-cleaning of water. However, it proceeds slowly. While industrial domestic discharges were small, the river themselves coped with him. Due to the sharp increase in reservoir waste, it is no longer coped with such significant pollution. There was a need to neutralize, clean the wastewater and dispose of them.

Wastewater treatment - wastewater treatment in order to destroy or remove harmful substances from them. The release of wastewater from pollution is complex production. In it, as in any other production there is raw materials (wastewater) and finished products (purified water).

Wastewater solid methods

Cleaning wastewater is the destruction or removal of pollutants, disinfection and removal of pathogenic organisms.

There is a large variety of cleaning methods that can be divided into the following main groups for the main principles used:

- Mechanical They are based on the procedures for filtering, filtering, settling, inertial separation. Allow separating insoluble impurities. According to the cost, mechanical cleaning methods refer to one of the cheapest methods.

- Chemical Used to release soluble inorganic impurities from wastewater. When processing wastewater with reagents, they are neutralized, discoloration and disinfection. In the process of chemical cleaning, a sufficiently large amount of precipitate can accumulate.

- physico-chemical At the same time, coagulation, oxidation, sorption, extraction, electrolysis, ultrafiltration, ion exchange cleaning, reverse osmosis are used. This is a high-performance cleaning method, characterized by high cost. Allows cleaning wastewater from finely and coarse particles, as well as dissolved compounds (with the exception of true-dissolved compounds - for example, salts).

- biologicalThese methods are based on the use of microorganisms absorbing wastewater pollutants. Bio filters with a thin bacterial filmmaker are used, biological ponds with inhabiting them with microorganisms, aerotanks with active il from bacteria and microorganisms.

Combined methods are often used using various cleaning methods at several stages. The use of one or another method depends on the concentration and harmfulness of impurities.

Sorption methods of cleaning

Sorption is one of the universal deep cleaning methods from dissolved organic substances of wastewater such industries, such as coke-chemical, sulfate cellulose, chlororganic, semi-product synthesis, dyes, etc. To remove organic substances determined by the MIC, biological purification is suitable. To remove persistent organic substances determined by the CCD, biological cleaning is not effective. Even well-purified wastewater after biological purification has contamination with organic substances, the value of which by the COD is 20-120 mg / l. These substances include tannins, lignins, ethers, protein substances and other organic pollution, having chromaticity and odors, pesticides, such as DDT, and others. Sorption wastewater treatment is used both before biological treatment and after it. IN lately The possibility of replacing the biological purification of production and household wastewater sorption is investigated.

Unlike the biochemical process fluctuating the temperature and the effect of toxicity for sorption do not have such a large value, it is also easier to resolve the removal of precipitation and automation, complex for biological cleaning stations. The three types of sorption are used.

Adsorption - absorption of the substance by the surface most often of the solid absorber. The devices in which adsorption occurs is called adsorbers.

Absorption- Absorption, accompanied by diffusion of the absorbed substance in the depth of the sorbent with the formation of solutions. In most cases, absorption absorbers are liquid. The devices in which this process occurs is called absorbers, or scrubber.

Hemosorption - adsorption, accompanied by the chemical effect of the absorbed substance with the sorbent. Chemisorption is used in the technique when absorbed carbon dioxide, nitrogen oxide, ammonia, etc. The process is usually carried out in towers filled with a porous nozzle through which the waste water purified is filtered.

A variety of artificial and natural porous materials are used as sorbents: activated carges, ashes, coke trim, silica gels, alumino, active clay and land. The latter make up a large class of natural sorbents that have a significant absorption capacity without any additional processing, which is their advantage over artificial sorbents.

The most important indicators of sorbents are porosity, pore structure, chemical composition.

According to the structure of the porous surface, sorbents are divided into fine-sized, coarse and mixed. The magnitude of the sorption potential is higher in fine-sized sorbents, however, they are not always available to absorb wastewater pollution. Activated coals are usually available for absorption of molecular solids. Natural sorbents (tuffs, diatomites) are capable of absorbing groups of molecules.

Thanks to the chemical affinity of sorbents to recoverable pollution, the most common carbon sorbents is advisable to apply to removal from water are not involved or weakly dissociated substances of organic origin.

The activity of the sorbent is characterized by the amount of absorbed substance in kg per 1 m 3 or 1 kg of sorbent; Activity can be expressed in fractions or percentage of the mass of the sorbent.

The static activity of the sorbent is the maximum amount of substance absorbed by the time the equilibrium is the unit or mass of the sorbent at a constant water temperature and the initial concentration of the substance.

The dynamic activity of the sorbent is the maximum amount of substance absorbed by the unit of mass or the volume of the sorbent until the sorbed substance appears in the filtrate when the wastewater is passed through the sorbent layer. Dynamic activity is always below static. For example, in industrial adsorbers, the dynamic activity of activated coal is 45 - 60% static.

The adsorption of granular activated carbon is carried out in bulk filters or in the apparatus of coal fluidization.

Filtering through a fixed layer of activated carbon in bulk filters is made from top to bottom or bottom up (Fig. 1.).

Fig. 1. Diagram of adsorption doctors using activated anthracite

Streams: I - waste water for cleaning; II - regenerated anthracite; III - activated anthracite; IV-waste water on ion exchange filters; V - fresh anthracite for activation; VI - water vapor; VII - natural gas; VIIII-DEVICE GASES; 1 - adsorber; 2.3-oven, respectively, regeneration and activation of anthracite

In this case, it is planned to pre-clean wastewater from suspended substances on sand filters, since their presence in the amount of more than 10 g / m 3 causes a rapid rise in pressure losses in sorption filters. The most commonly practiced sequential operation of sorption filters with water filtration rates from 1-2 to 5-6 m / h through loading with grain size from 1.5-2 to 5-6 mm. Filters with a fixed layer of coal are most rationally used in regenerative cleaning of workshop sewage. When desorption, carried out by chemical solvents or steam, not only the restoration of the sorption capacity of coal, but also the extraction of the product having technical value is achieved.

In the apparatus with fluidization of activated carbon, the wastewater is reduced from the bottom up with the speeds of 7-10 m / h. At the same time, coal with a particle size of 0.5-1 mm is stirred by the ascending flow of water and as it is saturated from the upper plates to the lower. Small weighted particles of wastewater pollution are taken out of the adsorber and can be removed together with the drains of other workshops on common sewage treatment facilities. Such wastewater treatment places increased requirements for activated corner, since it is subjected to significant abrasion when fluidizing and hydrotransporting.

Adsorption of powdered activated carbon. The decrease in the size of the activated carbon particles is little affected on the limit capacity of the sorbent, but very strongly affects the rate of adsorption. The powdered activated carbon with a particle size of about 10 microns reaches 90% of the equilibrium state in less than 19 minutes, while for granular coal will be required for several days.

The cleaning process using powdered coal flows into several steps. At each stage, stirring of activated carbon with waste water and reagent (polyelectrolytom), flocculation and upholding are carried out. Sewing water from the latter stage is filtered through a sand filter for detention of activated carbon, which cannot be separated by defending.

An even greater use of sorption capacity can be achieved in a multistage countercurrent process. The coal pulp is pumped towards sewage from subsequent steps in the previous ones. The disadvantage of such an installation is its bulkiness.

In Misi named V. V. Kuibyshev, a method for sorption sewage treatment with filtration through fine activated carbon was developed. The method is based on the use of wicked filters as adsorbers. The technological scheme is represented by several wicked filters. The first of them with the loading of the auxiliary filtering powder (diatomite, perlite, etc.) is set to detention of suspended pollution. Subsequent filters are adsorbers with a developed surface of the phase contact due to the fact that the finely dispersed activated carbon is located on a significant surface of the naming filters. The countertocks in the scheme are organized by switching devices with inaccurated coal towards wastewater. The filter layer on the inner surface of the filter is mounted from the tank-suspension using the pump. Removal (washing) of the spent material is carried out by reverse current of water. The flirt washed after the pressure loss in it 0.36 MPa, washed off coal - only from the first but the course of the water of the adsorber during the depletion of its sorption capacity.

This scheme was tested for cleaning wastewater from trinitrotoluole with the initial concentration of 50 g / m 3 and the final not more than 0.5 g / m 3. When water intakes 2 m 3 / h per 1 m 2 of the filtering surface, the best options are the three-stage adsorption at the carbon consumption of the OMA brand at each stage of 2.5 kg / m 2 (0.13 kg of coal / m 3 of water) and the frequency of adsorber recharge frequency / \u003d 2.5 times a day or four-stage adsorption at the consumption of coal of the brand of CAD 5 kg / m 2 (0.193 kg of coal / m 3 of water) and / \u003d 1.85 times a day

Such a scheme provides high quality purified water, both by the content of suspended substances and in the content of dissolved organic contaminants. In the cleaning system, small amounts of water and coal are involved, which predetermines the compactness of the equipment.

Adsorption and separation operations of water and coal are combined. The coal at the same time is significantly less susceptible.

To restore the sorption capacity, the activated carbon spent during the adsorption process is usually subjected to regeneration by chemical solvents, ferry or heat treatment.

Thermal regeneration of activated carbon is carried out in multi-winding furnaces. The total residence time of coal in the furnaces ranges from 30 to 60 minutes at a temperature of from 600 to 900 ° C. The loss of coal is from 5 to 10%.

After adsorption purification, it becomes possible to reuse wastewater in a circulating water supply system. The use of technological wastewater in a circulating water supply system solves not only the task of saving fresh water, but also radical rehabilitation of water bodies.

The disadvantage of sorption treatment of wastewater is its relatively high cost.

Conclusion

Among the physicochemical methods for cleaning wastewater from petroleum products, the best effect gives sorption on coals.

Sorption is the process of absorption of a substance from ambient solid body or liquid. The absorbing body is called the sorbent absorbed by the sorbate. The absorption of the substance is distinguished by the entire mass of the liquid sorbent (absorption) and the surface layer of solid or liquid sorbent (adsorption). Sorption, accompanied by chemical interaction of the sorbent with an absorbable substance, is called chemisorption.

Sorption is one of the most effective methods Deep purification from dissolved organic matter wastewater enterprises of the petrochemical industry.

Different porous materials are used as sorbents: ash, coke, peat, silica gels, alumino, active clays, etc. The effective sorbents are activated carbons of various brands. Depending on the scope of the method of sorption cleaning, the location of the adsorbers in the total complex of sewage treatment facilities, the composition of wastewater, the form and size of the sorbent, etc. Assign one or another scheme of sorption cleaning and type of adsorber. The simplest filter is the simplest filter, which is a column with a fixed layer of a sorbent, through which the wastewater is filtered. The most rational directional direction of fluid filtration is from the bottom up, since in this case there is a uniform filling of the entire cross section of the column and the bubbles of air or gases falling into the sorbent layer along with waste water are relatively easily supplanted.

Bibliography

F.V. Stolberg ecology of the city. K.: Libra, 2000.

L.S. Alekseev quality control of water. M.: Infra - M, 2004.

S.I. Rozanov overall ecology. St. Petersburg: ed. "Lan", 2003.

L.L. Palia, Ya.y. Karu, H.A. Melder, B.N. Repin Handbook of the purification of natural and wastewater. M.: Horsis. Sk., 1994.

Yu.V. Voronov, E.V. Alekseev, V.P. Salomeev, E.A. Pugachev drainage. M.: Infra - M, 2007.

IN AND. Korobkin, L.V. Ecology. Rostov N / D: ed. "Phoenix", 2000.

Sorption methods

Sorption methods are based on the absorption of solid phase radionuclides in the mechanisms of ion exchange, adsorption, crystallization and others.

Sorption is carried out in dynamic and statistical conditions. With dynamic sorption, the filtration of the initial liquid waste is carried out continuously through the sorbent, and with static sorption, the time contact of the two phases is carried out when stirring with further division.

Dynamic sorption is carried out in wet or bulk filters. The difference lies in the fact that sorbents are used in bulk filters in the form of grainy durable material; In the wash filters, inorganic and organic materials Artificial and organic origin.

For the purification of liquid radioactive waste from radionuclides, sorbents (ionites) of such types such as KB-51-7, KU-2-8 (sylnic acid cation), AB-17-8 (highly binding anion), An-31 and An-2FN ( Low-home anions), vermiculitis. Sorbents are produced in the form of granules that are soaked in a special solution to activate. All listed sorbents have high purification coefficients and good filtering properties.

Ion-exchange heterogeneous reactions are reversible, which allows the regeneration of the sorbent, but determines the creation of conditions for leaching radionuclides during the storage of the spent sorbent. The exchanging capacity of the sorbent is almost all used on sorption of macrosconents - salts, due to their similarity with the properties of microcomponents. Then, in order to flow sorption of microcomponents (radionuclides), it is necessary to conduct preliminary desalting. Otherwise, it will lead to frequent regenerations of the sorbent and, consequently, an increase in the cost of cleaning.

Liquid radioactive waste with high salinity is unprofitable to clean with organic sorbents due to the fact that the regeneration of the sorbent requires 2-2.5 multiple of the excess of the pitch and acid (the cost of purification is required).

The situation appears inverse for radionuclides, in which the properties are different from the properties of macrocomponents. Multivalent radionuclides are well sorbed on cation in the presence of sodium ions. Therefore, sodium-ions are not sorbitated in liquid radioactive waste, which leads to a noticeable decrease in the volumes of the regenerator, secondary waste and the frequency of regeneration.

The use of synthetic organic sorbents allows you to remove all radionuclides in ion form from liquid radioactive waste. But such sorbents have some restrictions on the application that will develop into serious disadvantages. When using such sorbents of radionuclides in a molecular and colloidal form from liquid radioactive waste are not deleted. Also, if there are colloids or organic substances with large molecules in liquid radioactive waste, then the sorbent loses its properties and fails due to the clogging of pores.

In practice, before carrying out ion exchange to remove colloidal particles, filtering on wam filters is used. The use of the coagulation method instead of filtering leads to the formation of large amounts of waste. Organic compounds of liquid radioactive waste are removed by ultrafiltration. One of the main disadvantages of the use of ion exchange for cleaning liquid radioactive waste is the need for preliminary preparation of such waste.

For cleaning high-active liquid waste, synthetic organic sorbents are not used in view of their instability to the effects of highly active radiation. Such an impact leads to the destruction of the sorbent.

To ensure a high degree of cleaning, the process of ion exchange cleaning is carried out in two stages. At the first stage, salts and small amounts of radionuclides are removed from liquid waste, and already at the second stage, it is possible to directly remove nuclides from desalted liquid waste. The regeneration of the sorbent is made by countercurrent. To increase the performance of filters, the speed at the beginning of the cycle is set to (90h100) m / h, and at the end of the cycle decreases to values \u200b\u200bin (10h20) m / h.

Cleaning of desalted waste makes it possible to use effective mixed action filters (their regeneration is difficult) and wicked filters in view of the fact that when cleaning such waste, the need for regeneration is minimal. Due to the ridiculous loading of the anionics and cationites in the formations of H + and it, the anti-nipional effect is eliminated, and this leads to an increase in the degree of cleaning and the possibility of increasing the filtering rate to 100 m / h.

All liquid radioactive waste contains in one or another amount of suspension, which have a tendency to molecular and ion exchange sorption. Also, corrosion products with hydrated iron, manganese, cobalt and nickel can sorbit microcomponents. In this regard, it is proposed to separate the suspension for a noticeable improvement in the degree of purification of liquid waste.

To remove such components from waste as 137 CS, 99 SR, 60 CO, use the addition of selective sorbent, in this case - Nanoglin (Montmorillonite), which provides 98% cleaning from these components. Sorption on selective components are carried out in combination with coagulation.

Chemical deposition is one of the effective options for static sorption. The advantages of chemical methods include low cost, availability of reagents, the possibility of removing radioactive microcomponents in ion and colloidal forms, as well as the processing of saline liquid waste.

The main feature of chemical precipitation is the selectivity to various microcomponents, especially to 137 Cs, 106 RU, 60 CO, 131 I, 90 SR. Coagulation and softening are methods of chemical deposition; When applying these methods, cleaning from radionuclides in colloid, ionic and molecular forms is purified.

When using Caco 3 and MgOH 2 softened softening and MgOH 2 are precipitated and serve collectors for 90 SR, which is removed by crystallization with Caco 3. Also use this method Allows you to remove 95 Zr and 95 NB.

Cesium (137 Cs) is removed by deposition of iron ferrocyanids, nickel (most effective), copper and zinc, while the cleaning coefficient is 100.

Ruthenium (106 RU) and cobalt (60 CO) are poorly concentrated in precipitation due to the large number of their chemical forms. Ruthenium removal is made by sorbents such as cadmium sulphide, iron sulphide, lead sulfide. Cobalt purification is effective on chromium and manganese oxyhydrates. Radioactive iodine 131 I is made by the coaching of copper or silver.

Chemical precipitation is completed by phase separation procedures. In the separation of the phases, the larger part of the liquid waste and the concentration of sludge is underway. The separation of the phases is made by filtration or exposure to the system by a power field, which can be gravitational (sumps and clarifiers) and inertial (centrifuges). Due to the formation of large volumes, a pulp of a very high humidity, sumps are used extremely rarely, using clarifier for this. Lightening in such devices goes with high speeds and provides a high degree of purification.

For further lightening fluid, filtering is carried out. The use of bulk filters provides more subtle filtration, such filters have greater performance, and with their regeneration a small amount of waste is formed. The bulk filters were more common due to simplicity and reliability, despite the formation of a large number of secondary waste during regeneration.

Sorption methods are the most common to release chromium from the wastewater of electroplating. They can be divided into three varieties:

1) sorption on activated carbon (adsorption exchange);
2) sorption on ionics (ion exchange);
3) Combined method.

Adsorption method.

The adsorption method is one of the effective methods for the extraction of non-ferrous metals from the wastewater of electroplating. Activated coals are used as sorbents, synthetic sorbents, production waste (ash, slags, sawdust, etc.).

Mineral sorbents - clays, silica gels, aluminohels and metal hydroxides for adsorption of chromium from wastewater are used little, since the energy of the interaction of them with water molecules is large - sometimes exceeds the adsorption energy.

The most versatile from adsorbents are activated corners, but they must have certain properties:

- weakly interact with water molecules and good
- with organic substances;
- be relatively coenproof;
- have a high adsorption container;
- have a low restraining ability during regeneration;
- have high strength;
- possess high wettability;
- have low catalytic activity;
- Have a low cost.

The process of adsorption extraction of the hexavalent chromium from wastewater is carried out with intensive mixing of the adsorbent with a solution, when filtering the solution through the adsorbent layer or in a pseudo-lived layer on the periodic and continuous installations. When mixing the adsorbent with a solution, activated carbon in the form of particles with a diameter of 0.1 mm and less is used. The process is carried out in one or more steps.

Near the researchers studied adsorption of chromium on activated carbon as a pH function.

It has been established that chromium (VI) is easily adsorbed on an activated angle in the form of anions, such as HCRO4 - and CRO4 2-. In some works, it is shown that pre-processing of adsorbents nitric acid Increases their sorption capacity by chrome (VI).

There is a method for adsorption of chromium from wastewater when using solid lignin. It was established that the sorption process depends on the pH of the solution and the dose of lignin. The optimal contact time of the solution with lignin is 1 hour. As a sorbent, activated carbon is mainly used, other sorbents are used extremely rarely. As other sorbents in various studies are offered:

a) waste of the brewing industry (cardboard with sorbed strain of yeast saccharomyces carlsbergensis;
b) wood sawdust, preferably pine treated with a copolymer of monoethanolamine vinyl ether with 4-methylazagepta-3,5-diode -1,6-diol vinyl ester (SVEMVE);
c) vegetable material (lignin sludge, cellulose, etc.);
d) iron sawdust;
e) zeolites, silica gels, bentonite;
e) clays;
g) vermiculitis.

Advantages of the method

1) Cleaning to MPC.
2) the possibility of joint removal of various impurities by nature.
3) Lack of secondary pollution of purified water.
4) the possibility of recovery of sorbed substances.
5) the ability to refund the purified water after the pH adjustment.

Disadvantages of the method

1) high cost and deficiency of sorbents.
2) Natural sorbents are applicable to a limited circle of impurities and their concentrations.
3) the bulky equipment.
4) high reagent consumption for sorbent regeneration.
5) the formation of secondary waste requiring additional cleaning.

Ionic exchange method.

The ion exchange removal of metals from wastewater allows recovery valuables with a high degree of extraction. Ion exchange is the process of interaction with a solid phase solution, which has properties to exchange the ions contained in it, on the ions present in the solution. Substances that make up this solid phase are called ionics. The method of ion exchange is based on the use of cationites and anions that are sorbed from the treated wastewater cations and anions of dissolved salts. In the process of filtration, exchange cations and anions are replaced by cations and anions extracted from wastewater. This leads to the depletion of the metabolic ability of materials and the need for their regeneration.

Most practical value For wastewater treatment, synthetic ion exchange resins have been acquired - high molecular weight compounds whose hydrocarbon radicals commise a spatial mesh with ion-exchange functional groups fixed on it. The spatial hydrocarbon mesh is called the matrix, and the exchanging ions - counterions. Each counterion is connected to the oppositely charged ions called anchor. The reaction of ion exchange proceeds as follows:

RH + NaCl \u003d RNA + HCl,

when contacting cation,

where R is a matrix with fixed ions; N - Antiode,

ROH + NaCl \u003d Rcl + NaOH,

when contacting anion.

To extract from the wastewater of electroplating production of trivalent chromium cations, n-cations, chromate ions CRO32- and bichromate ions CR2O72- are removed on anionics AB-17, AN-18P, AN-25, AM-P, AM-8. The capacitance of the anionic chromium does not depend on the size of the pH in the range from 1 to 6 and is significantly reduced with the increase in pH more than 6.

At the concentration of a hexavalent chromium in a solution from 800 to 1400 eV / l, the ANIONITE ANIONITE AV-17 is 270 - 376 mol * eq / m 3.

The regeneration of highly binding anionics is carried out with 8 - 10% solution of caustic soda. Eloats containing 40 - 50 g / l of hexavalent chromium can be directed to the production of sodium monochromate, and purified water is reused.

Based on VLGU, the technology of local cleaning of chromium-containing wastewater was developed in order to extract heavy non-ferrous metals compounds, incl. And chromium sorption on highly binding anionate. The degree of water purification on this technology is more than 90 - 95%. Purified water corresponds to GOST 9.317-90 and is quite suitable for use in systems of closed waters.

Made: ECOS-2 filters in VNIICHT, sorbents: in the NTC "Musorb" (prominent, Moscow region), MP "Search" (Ashgabat), TET TOO (Dolgoprudny, Moscow region), VNIICHT (Moscow).

INOVAN UMWELTTECHNIK GMBH & CO KG has developed a block-modular installation of the REMA system designed to purify production wastewater from heavy metals. The single block is an ion exchange column in which 4 replaceable cassettes are installed vertically under each other. In the process of cleaning, wastewater is consistently passed through these cassettes from the bottom up.

The degree of contamination of the ion exchange resin is determined using indicators.

At the factory "Soilomash" (Kirov) introduced the process of purification of galvanic industrial industries from chromium ions with fibrous materials. For sorption of chromium anions, the material of the VION AC-1 is used, which has highly binding vinylpyridinium groups with 1.1 - 1.2 mg * eq / g. Made two sorption columns from corrosion-resistant steel of 50 liters each. Chromium sorption depends on its concentration in the initial solution. So, if the concentration is up to 10 mg / l, then it is not detected in the filter. However, at the concentration of chromium anion 75 mg / l and above, its contents in the filtrate 0.04 - 0.01 mg / l, which is permissible at a closed cycle. The effect of the initial concentration of the chromium solution on its content in the filtrate is due to the high ion radius of CR2O72-, causing steric difficulties when sorption on fiber hemosorbent. With a high chromium content, reduce the rate of supply of the solution to the sorption column. In this case, the degree of purification increases. When the saturation of the sorption columns is reached, they are removed from the stand and transported to the separation of galvanochemical processing for the regeneration of the chemisorbational material and recycling eluate. Regeneration VION AS-1 is carried out with a solution of Na2CO3. In this case, 50 liters of the solution are poured into each column and leave it for 3 hours. The subsequent operation consists in washing the filter with water.

A study was conducted 8 fibrous sorbents used to clean wastewater from heavy metal ions (AG, HG, CR, CD, FE). It is installed that the fibrous sorbents of Pan-PEA, Pan-TTO-μCC and coal fiber effectively purify wastewater from Heavy Metal ions. They are easily regenerated by treating acids and can be repeatedly used for cleaning. From the solution obtained after the regeneration of fibers, it is possible to highlight metals and re-use them.

Synthesized ion exchange materials based on waste and knitted production wastes containing polyester, polyacrylonitrile fiber.

It has been established that the synthesized ion exchange fibers exhibit selective ion exchange properties.

In the laboratory conditions, the selection of chromium was studied from the washing wastewater of electroplating workshops using ion exchange resins (ion exchange resins in the type "Wolfatit" (Germany) stamps SWB, SZ, SL, SBK, AD-41 and activated carbon stamps AS) and carbonaceous sorbents.

The KREBS & CO.AG (Germany) system of the company "KREBS & CO.AG" (Germany) includes a preliminary filter, valves, pipelines, pumps, water quality control devices for its electrical resistance and two-integrated ion exchange columns with a capacity of 1.5 - 4 m 3 / h . One of the columns is used for a direct purpose, the other is regenerated by another at this time. The described system consists of individual modules and therefore easily mounted and dismantled.

Advantages of the method

1) The possibility of cleaning to the requirements of the MPC.
2) Return of purified water to 95% in turnover.
3) the possibility of disposal of heavy metals.
4) the possibility of cleaning in the presence of effective ligands.

Disadvantages of the method

1) the need to pre-purify wastewater from oils, surfactants, solvents, organics, suspended substances.
2) high consumption of reagents for the regeneration of ionics and the processing of the resin.
3) the need for a preliminary separation of washing water from concentrates.
4) bulky equipment, high cost resin
5) the formation of secondary eluate waste requiring additional processing.

February 3, 2005

Currently, various technologies are used to clean industrial sewage. The most common is the reagent, in which heavy metals ions (CR 3+, Ni 2+, Cu 2+, Zn 2+, Cd 2+, Fe 3+, etc.) are translated into almost insoluble hydroxides of these metals with an alkaline reagent. and stand out from the aquatic environment with setting and filtering. As alkaline reagents entered into the cleaned stock, sodes (calcined or caustic) or hated lime Ca (OH) 2 (lime milk) are used.

The reagent method for cleaning wastewater has a number of flaws.

First, the concentration of heavy metal ions and the hydrogen indicator (pH) in wastewater constantly change. The technology for adjusting the pH is very inertial and cannot provide a timely change in the required dose of alkaline reagent. This circumstance leads to incomplete translation of heavy metal ions in their hydroxides and such iones beyond the sewage treatment plants in the composition of purified wastewater. Moreover, the concentration of heavy metals during their slipways in the form of ions can be ten times to exceed the MPC. Secondly, when applying reagents increases the already high singeling of purified wastewater, which can serve as an additional obstacle when they are repeatedly used in technological operations.

The translation of heavy metal ions in their hydroxides by itself a good technological method, but the implementation of it by adding an alkaline reagent, followed by upholding and filtering through conventional sand filters significantly reduces efficiency and reliability as a rule, purified wastewater cannot be reused due to their low Quality.

The problem of ensuring high-quality purification of contaminated wastewater should be solved by simplifying the technological scheme, constructive design and operation of water treatment plants while simultaneously increasing the degree of purification, versatility, reliability, as well as the environmental safety of the technological process, the possibility of maximum and even fully automation of it.

In the light of the set fired requirements among well-known methods for cleaning the wastewater of electroplating shops to the specified standards (ion exchange, membrane, sorption), the most promising is the sorption, provided that the adsorbent applied in the technological process is capable of carrying out a long time (months and even years) to perform its functions of the water purifier, i.e., purify water filtered through it from the entire complex of harmful impurities in it when restoring the sorption activity of the adsorbent by means of regeneration carried out directly in the filter structure.

The sorption method for cleaning natural and wastewater using activated coal and zeolites is known for a long time. However, he did not find widespread due to the fact that these adsorbents are filtering materials of one-time use. Regeneration of activated carbon and zeolites costly and time-consuming operation and in the conditions of active water treatment facilities are practically not realized, because the unloading of the material from the filter is required, activating it outside the water treatment plant on a special installation, delivery of the degenerated material back to the water treatment plant and loading it into the filter structure . If you go along the path of one-time use of adsorbents, then besides the enhancing costs of material replacement, there is a possibility of environmental hazard, since large economic costs are required for reliable disposal of the exhaust contaminated adsorbent.

Disadvantages of the sorption method of wastewater treatment

The operational and economic disadvantages of the sorption method of purification of natural and wastewater with traditional adsorbents are eliminated when the water treatment of the adsorbent, which has a high surface activity of grains, allowing to restore the sorption capacity by technologically simple, short-term regeneration time carried out directly in the filter structure. The most effective basis for obtaining adsorbents with targeted regulated properties can serve aluminosilicate minerals, since in their structure, almost any additives of organic and mineral origin can be administered, which will give the surfaces of the grains. Required properties.

The distinctive and positive property of these minerals is the "defectivity" of their crystal lattice and the ability to cationic substitution. The layered tetraeookthedric structure of aluminosilicates allows you to take cations not only in your crystal lattice, but also into interlayer and interplanar spaces, as well as the basal plane of the mineral particles. Magnesium and calcium can serve as such metabolic cations, which have weak bonds with the surface of the mineral particles and in the aqueous medium are quite easily moving into the solution.

Magnesium and calcium cations, as shown by many years of research at the Department "Water supply and drainage" of the St. Petersburg State University of Communications, carry out a major role in the process of sorption extraction of wastewater pollution, participating at the beginning (by means of chemical impact) in the formation of new compounds, and then in the creation Colloidal structures of these compounds on the surface of the grains of the adsorbent and in the interzernal pore space. Therefore, in the manufacture of an aluminosilicate adsorbent in raw materials, magnesium and calcium compounds are introduced as an activating additive.

An important technological features of the activated aluminosilicate adsorbent are:

the ability to ion exchange alkaline earth and alkali metals (Mg 2+, Ca 2+, Na +) due to the "defectiveness" of the crystal lattice of the cationia, from which the adsorbent is manufactured;
an increase in the hydrogen indicator to 9 in the water profused through the adsorbent;
the emergence of positive ζ -potential on the border of the section "The grain of the adsorbent - liquid" when filtering the water through the adsorbent layer;
restoration of the sorption activity of an activated aluminosilicate adsorbent with respect to the ions of heavy metals by regeneration carried out directly in the filter structure.

In the manufacture of an activated aluminosilicate adsorbent, due to the natural ion exchange ability of the aluminosilicate base, a part of the trivalent aluminum by magnesium and calcium cations included in the activator, as well as filling the "vacancies" in the nodes of the crystal lattice and in the interlayer space above the cations. As a result of such targeted modification and activation of aluminosilicate raw materials, a granular material is obtained, which, when filing water through a grain layer, forms a weakly alkaline medium and a positive electrokinetic potential. The prerequisite for creating an alkaline medium is magnesium and calcium oxides formed in the structure of the adsorbent in the process of its manufacture. Magnesium and calcium oxides form hydroxides in water, thus increasing the pH due to the excess anions it is. The cations of heavy metals, falling into an alkaline medium, react and form labor-soluble hydroxides according to the scheme:

IU 2+ + 2H - ® IM (OH) 2 ¯;

Me 3+ + 3D - ® IM (OH) 3 ¯.

The product of solubility of heavy metals hydroxides is significantly less (in dozens and hundreds of times) the solubility of the hydroxides of magnesium and calcium, therefore, the equilibrium of chemical interaction is shifted towards the formation of hard-soluble hydroxides of heavy metals. In addition, metabolic cations Mg 2+ and Ca 2+ diffuse from the adsorbent into water, which also contribute to the increase in the pH of the medium due to excess anions, connected in the future in hydroxides of heavy metals. The diffusion of mg 2+ and Ca 2+ cations is possible due to the fragility of the cation of the cationia. Thus, micelles of heavy metals hydroxides are formed with further consolidation of them into the aggregates, the formation and growth of the colloidal structure due to the power of electrostatic interaction between the positively charged surface of the grains of the adsorbent and adversely charged micelles of heavy metals hydroxides.

In the process of filtering extraction from the water of heavy metals, the active part of the adsorbent, consisting of magnesium and calcium cations, producing into the aqueous medium, is gradually carried together with the filtrate. The moment occurs when the cleaning (protective) functions of the adsorbent become insufficient, and the concentration of heavy metal ions endowed with the filtrate exceeds the installed MPCs. Activation of the adsorbent is required, i.e. the replenishment of exchange cations departed along with water.

When choosing an activator to restore the sorption properties of the adsorbent, the three most important factors were taken into account:

first, the activator should be dissolved in water so that the activation is carried out directly in the filtering structure;
secondly, the ion exchange cation in a number of cations should be located higher than calcium and magnesium;
thirdly, this cation must have alkaline properties and be easily accessible to practical use. All these conditions are mostly responsible for the cation of sodium Na + as part of the calcined soda.

As the practice has shown, the processing of an activated aluminosilicate adsorbent 3-4 percent solution of calcined soda in circulation mode for 30-35 minutes restores the protective properties of the adsorbent, regardless of the number of regeneration cycles, i.e. for a long service life. The restoration of the sorption activity of the filter loading is carried out by treatment with a 3-4 percent solution of calcined soda in circulation mode with an intensity of 3 l × C / m 2. The regeneration solution is used repeatedly. Before restoring, it is necessary to wash the filtering load with water with an intensity of 14 l × C / m 2.

In 2004, research (S.-Petersburg) was conducted in the city of the city laboratory center of the State Sanitary and Epidemiological Supervision (St. Petersburg). To study the effectiveness of the adsorbent "Mlintest", distilled water was used as the initial sample, prepared with the addition of reagents containing metals: nickel sulfates, cadmium, manganese, zinc, copper and chromium, iron three chloride, lead nitric acid. As research results show, the adsorbent "Mlintest" has the ability to significantly reduce the concentration of heavy metal ions in aqueous solutions (table).

The technology of cleaning industrial wastewater using the activated aluminosilicate adsorbent is implemented:

for electroplating production at FSUE "Ryazan dashboard",
for the battery pack in CJSC "Electrotaging" (St. Petersburg),
OJSC "Plant for the production of diamond instruments" (Tomilino Moscow Region),
JSC "Murom Radiosavod" (Murom),
OJSC Stupinsky Metallurgical Combine (Stupino Moscow Region),
OJSC Memer (Smolensk)
and on a number of other enterprises.

For example, in the Stupinskaya Metallurgical Company OJSC (Stupino of the Moscow Region) since 2000, pressure filters with a capacity of 3500 m 3 / day loaded by activated aluminosilicate adsorbent (five filters of 16 m 2) are operated. The composition of contaminants entering filters, mg / l: petroleum products 20, CR 3+ to 10, Cu 2+ to 5, Fe 3+ to 10, Al 3+ to 5, Ni 2+ to 10, Zn 2+ to 5, pH 6-7.5. The filtrate composition corresponds to the values \u200b\u200bof the MPC of harmful substances for fishery water reservoirs. The adsorbent regeneration is performed in 5-7 days by a 3-percent solution of soda calcined. The remover of the adsorbent is about 5% per year. Cost of purification of 1 m 3 of sewage (according to the enterprise) - 4.5 rubles.

At this and other enterprises used activated aluminosilicate adsorbent with the following characteristics (according to GOST 51641-2000 "Materials filtering grainy. General technical instructions"): grain size 0.63-2 mm, volume weight 0.95-1 g / cm 3, Grinding to 0.5, abrasability up to 5, specific working surface9-12 m 2 / g, minimum pH value of filter water6.

conclusions

The experience of industrial exploitation of these objects shows that the technological process of sorption sewage treatment is characterized by reliability and economy when high quality. As a rule, purified wastewater is reused on technological needs. The transition of enterprises to a closed water supply cycle will improve the environmental situation in the region, ensure the rational use of water resources.

E. G. Petrov, Professor (St. Petersburg state University communication paths);
D. S. Kirichevsky, Director of CJSC Kvant Mineral (St. Petersburg)