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Purification of industrial and household sewage. The use of biological methods for the treatment of wastewater from industrial enterprises

: industrial and domestic.

Protection of reservoirs from pollution by wastewater from industrial enterprises and domestic - component protection of the environment from the harmful effects of human activity on nature. Pollution entering water bodies with wastewater from industrial enterprises and from settlements is the main violator of the ecological purity of the aquatic environment. To protect against these pollutions, preliminary wastewater treatment is used at the enterprises themselves and in settlements, before they are discharged into the system of rivers and reservoirs.

There are three types of wastewater - industrial, domestic and atmospheric. Industrial wastewater is generated when water is used in technological processes, when units are cooled (the temperature of waste water rises), in raw material and fuel storage facilities, in boiler houses, etc.

Domestic wastewater is generated in settlements and contains both solid and organic pollutants.

Atmospheric wastewater is formed from atmospheric precipitation and contains pollutants entrained by water from the air and during the melting of snow.

The amount of wastewater from industrial enterprises depends on the amount of treated effluent that is returned to the process after treatment and is regulated by recycling water supply treatment systems. Today, at metallurgical and oil refineries, 90-95% of wastewater after treatment is returned to the production cycle and only 5-10% is discharged into water bodies, taking into account the permissible MPC in them. However, these percentages must be significantly reduced as well. the volume of water consumed in modern production is growing significantly.

The content of pollutants in wastewater depends on the technological processes in which they participate, and the concentration of pollutants depends on the industry, feedstock, process mode, water consumption per unit of product. Wastewater from industrial enterprises contains mineral and organic pollutants in various combinations, and the uneven time of their entry into treatment (volley emissions) greatly complicates the work of treatment facilities.

Increasing the amount of wastewater entering for reuse (circulating water) and reducing specific consumption water per unit of production - the most significant ways to reduce wastewater discharge. Recovery of valuable wastes from wastewater for their return to the technological process also helps to reduce the concentration of pollutants in wastewater.

To reduce the cost of treatment systems, increase efficiency in operation at industrial enterprises, the combination of effluents from different technological processes of one enterprise is often used. However, this is not always possible and it is necessary to remove wastewater from different technological processes in separate effluents. Separate disposal of effluents is sometimes associated with different concentrations of substances to be disposed of at different stages of the process.

After the treated wastewater enters the reservoirs, the quality of the water in them changes little and the water remains harmless, but only up to an acceptable environmental barrier, after which its properties begin to change due to the intensification of chemical, physicochemical and biochemical processes. Sometimes these processes lead to the precipitation, transformation and decomposition of harmful substances, which improves the quality of water in reservoirs. These processes are called self-purification. If the water in reservoirs is diluted with clean water, then in combination with self-purification, the neutralizing ability of the reservoir is significantly increased.

Wastewater treatment processes are divided into:

1. Mechanical wastewater treatment.

2. Physical and chemical wastewater treatment.

3. Biological wastewater treatment.

As you can see, industrial wastewater treatment is of great importance for the environment, so treatment facilities must be constantly improved. The cleaning process ends with the processing of sediments.

Lecture plan:

Technological schemes.

Layout of treatment facilities. Blocking of treatment facilities.

Schemes of compact treatment plants.(0,08; 3 h).

The construction of treatment facilities can be solved locally, however, this leads to the construction of a large number of facilities with low capacity and, accordingly, to an increase in capital investments. The cost of building large treatment facilities that receive wastewater from several facilities, even if main collectors are built, is significantly lower than the cost of building treatment facilities for each facility separately. Improving the efficiency of capital investments is associated with the enlargement of wastewater treatment facilities through the creation of regional schemes for water disposal and treatment of industrial and domestic wastewater. The district scheme includes general treatment facilities, a drainage network with pumping stations of industrial enterprises and settlements of the district. To develop a district scheme for water disposal and wastewater treatment, the cost of the land on which the general treatment facilities and all industrial enterprises and settlements gravitating to them are located is determined. This scheme provides for the complete treatment of a mixture of industrial and domestic wastewater with their subsequent use in the recycling water supply system of industrial enterprises or for irrigation in agriculture. Treatment facilities are designed during a feasibility study. The introduction of district schemes for water disposal and treatment of industrial and domestic wastewater in river basins makes it possible to reduce capital investments and operating costs.

circuit diagram joint treatment of industrial and domestic wastewater is shown in Fig. 123

Rice. 123. Schematic diagram of the joint treatment of industrial and domestic wastewater with reuse of treated wastewater. 1 - settlement; 2 - industrial enterprise; 3 - local treatment facilities; 4 - biological treatment facilities; 5 - post-treatment facilities; 6 - drainage network; 7 - reserve release into the reservoir.

Joint treatment of domestic and industrial wastewater is carried out at large aeration stations with a high purification effect. The quality of wastewater that has passed through aeration stations is characterized by suspended solids of 5 mgO2 /l and BOD 10 mgO 2 /l, and with post-treatment up to 3 and 6 mgO2 /l, respectively.

Deep cleaning on sand filters and disinfection at aeration stations make it possible to bring the quality of treated wastewater in terms of suspended solids and BOD5 up to 2 mgO2 / l.

The efficiency of treatment at aeration stations largely depends on the scheme of preliminary wastewater treatment at industrial enterprises before they are discharged into the city sewerage network. At industrial enterprises, local treatment of industrial wastewater should be carried out before they are discharged into the city drainage network, and at city treatment facilities - complete joint biological treatment. The work of local treatment facilities should be efficient, since the entry of harmful substances that violate biochemical processes into the city drainage network is unacceptable.

Rice. 124. Technology system facilities for deep joint treatment of industrial and domestic wastewater. 1 - the building of lattices; 2 - sand trap; 3 – pipeline for coagulant supply; 4 - primary sump with built-in flocculation chamber; 5 - aeration tank; 6 - secondary sump; 7 - air duct; 8 - filter with granular loading; 9 – filter with zeolite loading; 10 - chlorine pipeline; 11 - contact reservoir; 12 - pipeline for treated wastewater; 13 - pipeline for supplying excess activated sludge; 14 - aerobic mineralizer; 15 - pipeline for supplying stabilized activated sludge; 16 - pipeline for supplying raw sediment; 17 - centrifuges; 18 pipeline for centrifuge return; 19 - conveyor for supplying sludge for composting; 20 - sites for sludge composting; 21 - emergency silt pads.

Biological treatment (Fig. 124), whether it will be carried out at enterprises or at urban wastewater treatment plants, should be considered as deep, providing the possibility of reusing treated industrial wastewater. At the same time, it is more expedient to treat wastewater at large (district) treatment facilities that are designed, built and operated, as a rule, at a higher level than small treatment facilities. 2 n 3 s 9 e buildings of individual enterprises

ty. Concerning great importance has the development of requirements for the quantity and quality of industrial wastewater sent to the city drainage network. Preliminary reagent treatment of wastewater is advisable to carry out at aeration stations in cases where it is necessary to increase the degree of joint treatment of industrial and domestic wastewater or increase the throughput of the station. Such a need arises in connection with the inflow of wastewater with a high concentration of contaminants caused by their significant content in industrial wastewater. Physical and chemical treatment facilities are designed for wastewater with sharply fluctuating inflow according to the seasons of the year, for facilities with a high percentage of industrial water content in urban wastewater (more than 50%) and for facilities where it is necessary to isolate biogenic elements from wastewater. Treatment facilities are designed for throughputs of 1.4; 2.7; 4.2; 7; ten; 17 and 25 thousand m3 /day On fig. 125 shows a plan of treatment facilities throughput 17 thousand m3 /day

Rice. 125. Scheme of the general layout of facilities for physical and chemical treatment of industrial wastewater. 1 - receiving chamber; 2 – grating building; 3 - aerated sand traps; 4 water measuring tray; 5 - sand platforms; 6 – sediment thickener; 7 - pumping station for sand traps and primary horizontal settling tanks; 8 - horizontal settling tanks 6 m wide with a built-in flocculation chamber; 9 – block of filters Oksipor; 10 - block of tanks; 11 - contact tank; 12 - chlorination; 13 production and auxiliary building; 14 - administrative building; 15 - reagent facilities; 16 - facilities for sludge treatment.

In the project, the initial concentration of pollutants for suspended solids and BODtotal is 300 mg/l. The effect of coagulation cleaning is

Waste water enters the receiving chamber, passes successively grates, sand traps, a water-measuring flume and enters the mixing chamber, where a 10% coagulant solution is supplied by dosing pumps. Mixing of coagulant with waste water is carried out by compressed air. Further, the waste water passes into the flocculation chamber and enters the sump, after which further purification is carried out on Oksipor filters. Filtration takes place in a downward flow of liquid at a constant liquid level above the load, which is maintained by a siphon installed on the filtered water pipeline. The filtrate is collected by the distribution system and then removed for disinfection to contact tanks. Filter loading - expanded clay with a particle size of 5 - 10 mm and gravel. The filters provide continuous aeration of wastewater. Restoration of filtering capacity is carried out by water-air washing. BOD decreases on Oxypor filters.5 up to 80%, and the concentration of pollutants in suspended solids up to 90%.

From the filters, treated wastewater under hydrostatic pressure through the pipeline enters the contact tank for disinfection with liquid chlorine. An emergency discharge from the receiving chamber and after the settling tanks into the bypass channel is provided.

Sedimentation centrifuges can be used to process the sludge, followed by drying in vacuum dryers.

Treatment facilities for wastewater systems using physicochemical methods were developed by VNII VODGEO together with Soyuzvodokanalproekt and are intended for deep treatment of a mixture of industrial and domestic wastewater.

At the department of V&V of the Institute of Urban Planning, Management and Regional Economics of the Siberian Federal University, a technology for deep cleaning of small sewage facilities in Siberia and the North has been developed

In the process of cleaning domestic wastewater of low productivity, as a result of their uneven discharge, periods of their long stay in the receiving tank and decay are possible.

When a liquid rots, complex, poorly coagulated complexes are formed, which must first be destroyed or the charges formed on their surface neutralized.

In recent years, in the technology of wastewater treatment, the electrolysis of aqueous solutions, used for the purpose of electrical destruction of both organic and inorganic compounds, has become increasingly widespread.

The mechanism of electrochemical oxidation (or reduction) of organic and inorganic substances depends on the material of the electrodes, the nature

contaminant components, temperature, the presence of foreign substances inhibiting the process.

To develop a technological scheme for deep purification of domestic wastewater, experimental studies of the electrocoagulation process using soluble Al-anodes on natural wastewater were carried out.

The electrolysis of wastewater on insoluble electrodes makes it possible to stabilize the properties of colloidal and dissolved particles in order to prepare the liquid for electrocoagulation.

Based on the results of the experiment, a technological scheme for the treatment of domestic wastewater was developed, shown in Fig. 126.

Fig.126. Technological scheme of domestic wastewater treatment 1 equalizing tank, 2 - grate, 3 - pump, 4 - 1st stage electrocoagulator, 5 first stage electrocoagulator containing aluminum electrodes, 6 first stage electrocoagulator containing graphite electrodes, 7 second stage electrocoagulator with soluble anodes, 8,9,10,11 filters of the first, second, third and fourth stages, 12 - fan,13

- vibration filter, 14 ozonator, 15 - vibrocompactor, 16 drum dryer-crusher, 17 - packaging, 18 - electric heater

The process of domestic wastewater treatment is carried out as follows: the waste liquid enters the equalizing tank (1), after passing through the coarse grate (2), the pump (3) is fed to the electrolyzer-coagulator (4) of the first stage, containing aluminum (5) and graphite (6) electrodes, from which it enters the vibrofilter (13) for the primary separation of sediment, then after passing the electrocoagulator (7) of the second stage with soluble anodes, it is further cleaned and disinfected in filters (8,9,10,11) of the first, second, third and the fourth stage, which are loaded on the first (8) and third (10) crushed expanded clay, the second (9) and fourth (11) - activated

coal; deep purification and disinfection of wastewater is carried out by ozonation in the filter body of the second (9) and fourth (11) stages, ozone is supplied from the ozonator (14). The sediment retained by the vibrofilter (13) is compacted on the vibrocompactor (15) and fed into the drum dryer-crusher (16), dried with the help of an electric heater (18) and discharged for packaging (17).

The proposed wastewater treatment technology uses cell models in electrocoagulation and filtration, which make it possible to divide the treatment process into stages with smaller load ranges for each of them and reduce the likelihood of a longitudinal breakthrough of contaminants, while the wastewater is bubbling with an ozone-air mixture in the body of a sorption-contact filter loading - activated carbon.

The reliability of the technology is ensured by:

primary electrooxidation, which gives a change in potential and the formation of a hypochlorite ion, which is an oxidizing agent and a disinfecting agent;

two-stage electrocoagulation;

four-stage filtration;

using a contact-sorption load for accumulation and averaging of contaminant concentrations;

ozonation in the body of the filter media for its continuous regeneration;

additional mechanical filtration after ozonation in the body of the filter load for its continuous regeneration;

additional mechanical filtration after ozonation to retain suspended particles - newly formed micelles;

using the spent ozone-air mixture in the equalization tank as pre-ozonation to reduce the risk of wastewater decay.

Thus, the multi-stage wastewater treatment technology adopted as a basis, including electrical treatment, sorption, ozonation, corresponds to the state of the art, high requirements for the quality of treated wastewater and can be used to solve the issues of deep cleaning of small sewage facilities in Siberia and the North, characterized by low temperatures and remoteness of sewage facilities from centralized systems.

The authorities for the regulation of the use and protection of natural resources and the bodies of the sanitary and epidemiological service require all industrial enterprises to minimize the discharge of industrial wastewater into the city drainage network through the use of rational technological processes, partial or complete water circulation, reuse of wastewater, extraction and use of the contained they contain valuable substances, as well as the disposal of toxic waste.

An increase in the technical and economic indicators of sewage treatment plants is facilitated by the blocking of individual structures that are part of the technological scheme of treatment. Blocking structures can significantly reduce the building area, reduce the volume construction works and in some cases improve the performance of facilities.

In the practice of designing and building treatment plants, rectangular and round interlocked structures are used. Rectangular blocks make it possible to use the building area more rationally, however, in many cases, round blocks may be preferable due to the working conditions of building structures.

To expand the treatment facilities, a block is proposed that includes a radial primary settling tank, concentrically located gas tanks with a regenerator and a secondary settling tank equipped with a moving airlift for pumping return activated sludge. New in the facility is the equipment of the secondary settling zone with thin-layer blocks, which will improve its performance by increasing the dose of sludge in the aeration tank and increasing the effect of clarification of the sludge mixture.

The scheme of operation of the facilities is as follows. Wastewater that has passed grates and sand traps enters the primary radial clarifier. The clarified water is collected by a prefabricated peripheral tray and is directed through pipes to the aeration zone of the aeration tank, where the regenerated activated sludge from the regenerator also enters after mixing it with clarified water. A mixture of clarified water and regenerated activated sludge is fed into the aeration zone evenly around the entire circumference of the zone through a distribution tray. The aerated sludge mixture enters the secondary settling tank through the jet-directing partitions, then, after passing through the thin-layer blocks, it is collected by the treated water collecting tray and discharged outside the block. Activated sludge settled in the secondary clarifier is pumped through a pipe to the regenerator using two moving airlifts mounted on a truss rotating around a central axis. On the same truss, a primary settling tank sludge scraper and a defoaming pump were installed, which irrigate the surface of the aeration zone with a sludge mixture during the rotation of the truss. Excess activated sludge is discharged into a stationary tray, from which it is removed through a pipe outside the structure. Air is supplied to the aerotank through ceramic filter tubes.

The main advantages of the described structure:

maximum blockage of primary sedimentation and biological treatment facilities, which made it possible to reduce the building area, the length of communications, reduce the volume of enclosing structures and hydraulic losses; the presence of a built-in regenerator, which ensures the operation of the aerotank according to the principle of a complete reactor

mixing;

the use of only two airlifts mounted on a rotating one for pumping activated sludge; 244

the ability to provide defoaming with one pump installed on a rotating farm and irrigating the surface of the aeration and regeneration zones;

the presence of thin-layer blocks in the zone of secondary settling, which make it possible to ensure the operation of the aerotank with increased doses of sludge, with a slight removal of suspended solids;

structural diagram of the block, consisting of four cylindrical tanks, allowing the use Wall panels factory-made with coiling of prestressed reinforcement.

When designing sewage treatment plants, as a rule, it is necessary to withdraw land from the suburban area, which are of great value. Therefore it is very important design work aimed at reducing the space required for construction. For this purpose, interlocked main and auxiliary structures are used instead of numerous separate structures at treatment plants.

So, for example, it is necessary to combine: a grate building, a boiler room, an office-laboratory, amenity premises, workshops, a transformer substation; sludge digesters, primary settling tanks, aerotanks, secondary settling tanks, contact tanks. All pumping stations can also be blocked.

At the Suprunovskaya sewage treatment plant in Poltava with a capacity of 20,000 m3 /day, primary settling tanks, aerotanks and secondary settling tanks were blocked, which made it possible to reduce the length of the bearing walls of the aerotanks by 150 m and partitions by 77 m.

When blocking facilities, not only areas decrease, but other indicators also improve: the cost of building treatment facilities in the village. Krasny Donets decreased due to the blocking of facilities by 18% of the treatment facilities of the Suprunovskaya station - by 11.7%. Blocking of structures leads to a reduction in the length of communications, to a decrease in consumption building materials and operating costs.

It is obvious that the development of sewage treatment facilities will be due to the intensification of wastewater treatment processes and the blocking of facilities.

The lack of land space, combined with high rents for allotted land for construction, makes it especially economically feasible to use compact treatment plants. The effectiveness of compact solutions lies not only in the reduction of construction areas, but also brings such additional benefits as a reduction in the size of the building structures of technological communications and intra-site roads, a reduction in the volume of earthworks, and, consequently, capital costs.

A compact block of process tanks, including primary and secondary settling tanks, can have 2 4 to 5 round in plan shape with concentric

the physical arrangement of individual structures. However, such an arrangement is inconvenient for the further development of the treatment plant, therefore, GDR specialists prefer blocks of process tanks with a rectangular shape in plan. Three main types of blocks of process tanks have been developed (Fig. 127): type I - for objects with a capacity of up to 25 thousand m3 /day; type II - for objects 25–50 thousand m3 /day; type III - for objects of 50 thousand m3 / day or more.

Compact treatment facilities cause the transition to rectangular horizontal settling tanks with a number of design features. So, if in the primary clarifiers traditional scrapers are used, which are moved from one clarifier to another with the help of a trolley, in the secondary clarifiers, sludge pumps are used, moving in the longitudinal direction. The distance between the supports of the scraper devices of the sedimentation tanks, developed by the Wassertechnik plant (Galle), is unified and is 4.2; 6; 8.4; 10.4 m. The length of the sedimentation tanks is 30 - 60 m. For large treatment facilities, aeration tanks with a pneumatic aeration system are used; for medium and small treatment facilities, aeration tanks are equipped with vertical mechanical aerators with a diameter of 0.9; 1.5; 2.4 m with 2-speed electric motor.

Rice. 127. Schemes of layout of process tanks. a). type I; b). type II; in) type III; 1 - pipeline of the initial waste water; 2 – primary settler; 3 - aeration tank; 4 - secondary sump; 5 - pipeline of treated waste water.

Compact treatment facilities can be made both in monolithic and in prefabricated reinforced concrete (with hermetic sealing of joints 60–80 mm wide with plasticized concrete).

Recently, for the treatment of surface runoff from individual catchment areas, more and more wide application find compact factory-made units that can be placed on the surface or underground without pumping incoming rainwater, which in this case eliminates its additional dispersion by pumps and increases the efficiency of the mechanical treatment unit. Such installations for local treatment of surface runoff, as a rule, are designed according to one scheme (Fig. 128) and include three zones: a coarse treatment zone (O), thin-layer settling (TO) and a filtration zone using an inert or sorption load, and, if necessary, both. Factory-made block combined structures (Fig. 128 a)

Rice. 128 Schematic diagram of combined (a) and modular (b) structures: O - coarse cleaning zone; TO - zone of thin-layer settling; MF - mechanical filter; SF - sorption filter.

in .

Rice. 129. Design of installations for local treatment of surface runoff ( in): 1 - supply of contaminated water; 2 - inlet water distribution devices; 3 oil gathering pipe; 4 – block of thin-layer settling; 5 - semi-submerged partition; 6 - drainage tray; 7 – block of adsorption purification; 8 - partitions; 9 - release of purified water; 10 - container for garbage; 11 - removable grille.

For compact combined structures, structural elements (inlet, outlet, distribution system, design of thin-layer elements and blocks of mechanical filtration and sorption) are extremely important.

The coarse cleaning zone by settling (O) is located in a separate section or a volume provided specifically for this purpose, designed to separate coarse explosives and floating and coarse oil products (d > 100–200 microns).

TO zone - designed for highly efficient thin-layer cleaning and retention of particles of fine suspension and oil products with a diameter of up to 30 microns in a reagentless mode. This zone is extremely important for the efficient and long-term operation of MF and especially SF filters.

The filtration zone is the zone of final purification to the required standards on mechanical or sorption filters.

The design of a block combined unit for local treatment of surface runoff, developed by ONIL PGUPS, with replaceable sorption cassettes-containers filled with an activated aluminosilicate adsorbent (AAA), is shown in fig. 129 in. Cassettes that have exhausted the supply of sorption capacity are replaced with new ones, and spent ones are sent for regeneration.

Oil products are collected by sorbing booms or discharged into an oil gathering well and then removed. Sediment removal can be

provided by transport or with the help of hydraulic elevators, sand pumps to nearby storage sites.

Similar facilities can also be used to treat industrial wastewater. Their structures are very different.

In domestic and foreign practice, modular-type installations are beginning to be widely introduced (Fig. 129 b), allowing you to easily select the required composition of facilities for the required quality of cleaning from separate standard modules: a storage tank equipped with a pump, a coarse cleaning module, a module with thin-layer blocks, a module with a mechanical or sorption filter, etc., with their manufacture from resistant materials (Fig. 130,131,132).

Maintenance of such facilities is periodic. It should be emphasized that combined structures, unlike modular ones, are concentrated in one block, take up less space and are less material-intensive, which meets the principles of resource saving.

Firms working in the field of water supply and sewerage (WSS) recommend numerous designs of local prefabricated structures.

Rice. 130. Modular installation for the treatment of storm drains type AL: 1 - sand trap; 1.1

On fig. 133 shows the SOR.2 oil separator for surface runoff treatment, including a settling zone, a thin-layer settling module with an upward movement of liquid, a coalescent filter made of polyurethane foam and a sorption filter loaded with polymer fiber-fibroil. Contaminated liquid enters settling zone 2 , then it passes through the thin-layer settling unit 3, the coalescent filter 4 and enters the sorption unit 5.

Rice. 133. Separator of oil products SOR.2: 1 - supply of waste liquid; 2 sedimentation sump of the separator; 3 – block of thin-layer settling; 4 – coalescent separator; 5 - sorption filter.

In this design, there are no devices in front of the thin-layer settling unit for uniform distribution water. The design of the thin-layer settling unit is more suitable for the removal of settling substances, rather than oil products. The issue of removing settled contaminants from the bottom surface has not been resolved. The sorption filter has an insignificant sorption capacity.

Installation "Svir" (Fig. 134) is designed to treat rainwater contaminated with particles of clay, sand and oil products.

Rice. 134. Installation for the treatment of rainwater "Svir": 1 - supply of wastewater; 2 – sand catcher 4 3 – semi-submersible partition; 4 - settling zone; 5 thin layer block; 6 - pits for sediment; 7 – swivel pipe; 8 – container for oil products; 9 - spillway; 10 - filter with floating load; 11 - lattice; 12 - crushed stone; 13 - floating loading; 14 - drainage of high resistance; 15 - removal of treated wastewater; 16 - drainage of low resistance; 17 - removal of wash water and sediment; eighteen

– level indicator; 19 - overlap; 20 - ventilation pipe.

The liquid to be purified enters the settling zone 4, where coarse particles and floating oil products are released, which are collected by a rotary pipe 7. Then the liquid enters the thin-layer settling unit 5, passing through which it is fed through the overflow 9 to the filter 12, 13.

The absence of distribution devices in front of the thin-layer settling unit, with a significant volume of the coarse cleaning zone of the installation, does not provide effective flow distribution. The presence of a hopper for sludge compaction simplifies the process of its removal. At the same time, the thin-layer settling module is not able to effectively remove small impurities, which will undoubtedly affect the duration of the filters.

Installation for physical and chemical treatment of storm drains type UFKh (Fig. 135), includes a runoff equalizer 1, a flocculation chamber with a floating load 11, a shelf (thin-layer) sump 12 and a filter with a floating load 13. This installation does not have effective devices for uniform flow distribution, which reduces the coefficient of volumetric utilization. The use of the flocculation chamber 11 with coarse-grained loading provides good conditions for the agglomeration of contaminants, which is especially important for thin-layer settling. Upward and downward thin-layer settling units in compact installations often use tubular elements of various shapes, as well as corrugated shelves. The use of tubular elements in many cases leads to excessive consumption of material and unstable operation due to clogging.

sedimentation. To intensify the process of removing sediment from a block of thin-layer elements, vibration of the block and hydrophobization of the surface of the elements can be provided.

Rice. 135. Installation for the treatment of storm drains type UFKh: 1 - runoff supply; 2 - pump; 3

- sediment thickener; 4 - transition module; 5 - hatch; 8.8 - dosing pumps; 9 chloramine solution; 10 - filter with floating load; 14 - piezometer.

As noted earlier, surface runoff in in large numbers contains highly dispersed suspensions. With insufficient preliminary purification, the sorbent layer retains not only the molecularly dissolved substance, but also these suspensions, working as a mechanical filter. Clogging of intergranular voids of the sorbent layer causes a rapid increase in head loss. In this case, there is a danger of premature disruption of the normal operation of the installation, which is confirmed by the experience of operating local structures. In addition, when filtering the surface runoff through the sorbent layer from top to bottom, air or gas bubbles released from the waste water block individual sections of the grain layer, which disrupts the uniform distribution of the flow over the entire cross section of the layer.

In the "Svir" unit, the liquid to be cleaned enters the settling zone 4, where coarse particles and floating oil products are separated, which are collected by a rotary pipe 7. Then the liquid enters the thin-layer settling unit 5, passing through which it is fed through the overflow 9 to the mechanical filter 10, then - to the sorption filter. The design of the mechanical filter as a whole implements the principle of two-layer filtration. The crushed stone layer 12 makes it possible to equalize the load on suspended solids, providing a more uniform dispersed composition of contaminants entering the filter with a floating load 13. In the filter with a floating load, the principle of filtration in the direction of decreasing grain size is implemented, which increases the dirt capacity of the filter, increases the filter cycle.

Rice. 136. Sorption filter "Svir" 1 - housing; 2 - supply pipeline; 3 - sort-

bent; 4 - drainage; 5 - discharge pipeline of treated wastewater.

The sorption filter (Fig. 136) is made in the form of a steel rectangular container, along the bottom of which a drainage pipeline is laid, and in the upper part there is a pipe for supplying wastewater. The lower part of the filter is filled with a sorbent (activated carbon or similar material). It is known that effective work devices with a stationary adsorbent layer largely depends on the uniformity of distribution and collection of purified water over the area of the adsorber. The use of drainage in the design of the sorption filter in the form of a perforated pipe wound with galvanized wire with a pitch of 0.5 mm makes it possible to achieve a uniform collection of liquid over the area of the adsorber.

The advantage of a particular design of a compact sorption purification module is determined by a combination of many factors: the type of sorbent used, the type of sorption layer, the uniform distribution of the liquid to be purified over the module area, the geometric characteristics of the module, the direction of the liquid flow, and the operating mode of the installation.

Rice. 137. Block of two-stage filters of JSC "Sevzapnaladka": 1 - supply of contaminated liquid; 2 - cassette filters of the first stage; 3 – cassette filters of the second stage; 4 - removal of the purified liquid.

A sufficient degree of pre-treatment of surface runoff before supplying it for sorption treatment largely determines the reliability and duration of the load. The efficiency and economy of the process is largely determined by the type of

sorbent. The use of inexpensive, effective sorbents makes it possible to reduce the cost of surface runoff treatment. It seems promising to use modified ceramic-based adsorbents, including activated aluminosilicate adsorbent (AAA), which provides:

the possibility of a directed change in its surface properties in the process of synthesis and regeneration of the load directly in the filter;

low aggressiveness in relation to the material of tanks, pipelines and other equipment used;

high efficiency of sorption of non-polar and low-polarity hydrophobic impurities (petroleum products), as well as heavy metals;

environmental friendliness;

fire safety.

In general, the technological scheme and composition of facilities for the treatment of surface runoff of industrial enterprises, as well as the volume of runoff to be treated, should be assigned in accordance with local conditions and environmental standards based on a technical and economic comparison of options.

test questions

Scheme of joint treatment of industrial and domestic wastewater.

What should be provided for deep joint treatment of industrial and domestic wastewater?

Scheme of a local installation for physical and chemical treatment of domestic and industrial wastewater.

How is the process of domestic wastewater treatment carried out with a multi-stage treatment technology?

When can a multi-stage technology of physical and chemical treatment of domestic wastewater be used?

What is the advantage of interlocked wastewater treatment plants?

Schemes of layout of technological capacities.

What main and auxiliary structures can be combined?

What new technical solutions can be used to expand the treatment facilities?

How can the area required for construction be reduced?

Lecture 1 General information about the drainage systems of industrial enterprises.………………………………………………… 3

Lecture 2 Features of the device and calculation of water disposal systems at industrial enterprises.…………………… 15

Lecture 3 Types of receivers and conditions for receiving industrial wastewater.………………………………………………………… 21

Lecture 4

Lecture 5 .

Lecture 6

METHODS AND FACILITIES FOR CLEANING INDUSTRIAL-

WASTEWATER…………………………. thirty

General information on the treatment of industrial wastewater. Mechanical treatment (straining of sewage). 30

Wastewater averaging by flow rate and pollution concentration.

………………………………………………………… 35

gravitational separation. Structures and basic calculations of structures.…………………………………………41

Lecture Removal of mechanical impurities in the field of centrifugal forces.

7 . …………………………………………………………………… 59

Lecture 8

Lecture 9

Lecture 10

Lecture 11 .

Lecture 12

Lecture 13

Lecture 14

Lecture 15

Lecture 16

Lecture 17

Lecture 18

Lecture 19

Lecture 20

Lecture 21

Lecture 22

Lecture 23

Waste water filtration, filter designs……66

Chemical methods of industrial wastewater treatment. Neutralization of waste water by reagent and filtration methods.……………………………………………91

Oxidative cleaning method.………………………………98

Physical and chemical treatment of industrial wastewater. Coagulation……………………………………………………110

flocculation. Intensification of the coagulation process.118

Electrochemical coagulation…………………………125

flotation cleaning. ……………………………………….132

Sorption methods for industrial wastewater treatment

in static conditions……………………….139

Adsorption treatment of industrial wastewater under dynamic conditions………………………………………….143

Extraction methods for industrial wastewater treatment

water. …………………………………………………….148

Purification of industrial wastewater by ion exchange……………………………………………………….156

The use of electrodialysis and hyperfiltration for desalination of industrial waste

water……………………………………………………………………162

Biological treatment of industrial wastewater. Building structures……………………………………..169

Biological treatment of highly concentrated wastewater. Additional treatment of biologically treated wastewater……………………………………………………………..183

METHODS AND FACILITIES FOR THE TREATMENT AND UTILIZATION OF INDUSTRIAL WASTE SLUDGE

WOD…………………………………………… 191

Features of methods and structures of facilities for the treatment of industrial wastewater sludge……..191

The main methods of dehydration and disposal of industrial sewage sludge……………………………….202

INTEGRATED USE OF DIFFERENT METHODS IN INDUSTRIAL WASTEWATER TREATMENT AND SLUDGE TREATMENT SCHEMES 0.056 216

Lecture Features of wastewater treatment and sludge treatment

24. acceptance of metalworking. ………………………….. 216

Lecture 25

Joint treatment of industrial and domestic wastewater. Blocking of treatment facilities. Schemes of compact

treatment plants……………………….235

Rice. 120. Technological scheme of the local installation of galvanic coagulation treatment of chromium-containing wastewater

Rice. 121 - Reservoir for receiving the emulsion; 2,3,4,5 - water intake tanks 1 - oh, 2 - oh, 3 - oh, 4 - oh washing; 6 sewage pumps

for cleaning; 7 ejector to enter the regenerated coagulant solution; 8.11 - electrolyzers of the 1st and 2nd stages; 9 - tubular mixer; 10 - vertical sump; 12 – pressure flotator; 13 – acid storage tank, 14 – alkali storage tank; 15 – supply tank of acid; 16 supply tank of alkali; 17 – flocculant supply tank; 18 – acid dosing pump; 19 - alkali dispenser pump; twenty

flocculant dosing pump; 21 - flow meters-rotameters; 22 - collection pocket for floating waste; 23 - mixing chamber; 24

flotation chambers; 25 - settling chamber; 26 – scraper mechanism; 27 - recirculation pump; 28 - water-air ejector; 29 - pressure tank; 30 - distribution pipes; 31 - diaphragms; 32 - boost pump; 33 - pressure filter aftertreatment; 34 - RFV; 35 - process water pumps; 36 - tanks for collecting the foam product; 37 - tank for processing sediments from tanks 1 and 2; 38, 39 - tank for processing oily liquid wastes of the 1st and 2nd stages; 40 - reservoir for collecting oil; 41 - tank for collecting the solution of the regenerated coagulant; 42 - pump for pumping sediments from tanks 1 and 2; 43.44 - pumps for liquid oily wastes of the 1st and 2nd stages; K3 - pipeline for supplying spent emulsions and solutions; K3.0 - pipeline for supplying wastewater for treatment; K3.1, K3.2 - wastewater pipeline after the 1st and 2nd stages of treatment; K3.3 - purified water pipeline; K3.4 - recirculation pipeline; K4 - emptying pipeline; P1, P2 - acid and alkali pipelines; T1, T2 - supply heat pipe and

Rice. 122. Technological scheme for the treatment of oil-emulsion wastewater from a metallurgical plant.

The composition of the structures: 1 - reservoir - equalizer; 2 - oil trap; 3 – pressure electrolyzer; 4 – vertical sump with built-in flocculation chamber; 5 - fast filters with granular loading; 6 - sludge accumulator; 7 - oily waste tank removed from the oil trap pit; 8 - tank for collecting film oil products from the oil trap; 9 - intermediate tank; 10 - clean water tank (RCW); 11 - hot water tank (RGV); 12 – reservoir of polluted water after filter washing (RPW); 13 - blowers; 14 - pumping station of the first lift; 15 - pumping station of the second rise; 16 – sludge pump; 17 - industrial water pumps; eighteen

The historical location of industrial complexes in residential areas of populated areas is not optimal. Water supply and sanitation systems in such agglomerations are also joint for residential and industrial area. On the large enterprises, as a rule, has its own water management system with a full technological cycle from water intake to its purification, neutralization and disposal of the solid phase.
Main elements of the water management system locality and its interaction with the natural environment are shown in fig. 4.15.
Water intake facilities take natural water from a surface water source. The pumping station of the first rise through pressure pipelines delivers it to the treatment plant. Here the water is purified to drinking quality and from tanks pumping station the second rise is supplied to the settlement, as a rule, having a ring water supply network. Water is used for drinking, household needs, watering streets and plantings, at local industry enterprises.

Rice. 4.15. The main elements of the water management of the settlement and their relationship with the environment:
1 - water intake facilities; 2 - pumping station of the first lift; 3 - treatment facilities; 4 - reservoirs; 5 - pumping station of the second rise; 6 - water supply network; 7 - sewer network; 8 - sewer pumping station; 9 - mechanical cleaning; 10 - biological treatment; 11 - disinfection of waters; 12 - biological ponds; 13 - discharge of purified water; 14 - rain network, artesian wells; 15 - treatment facilities; 16 - industrial enterprise; 17 - water circulation cycles; 18 - coolers
Used water (waste water) according to closed sewer network is diverted outside the city and the main sewer pumping station is fed to the city's wastewater treatment plant.
Here, wastewater undergoes mechanical and biological treatment, disinfected and fed to biological ponds, where it is purified in natural conditions. After the ponds, the water in its qualities differs slightly from the water of a natural reservoir and can be discharged into a river, lake, etc.
Atmospheric water, which is discharged by the rain network, is cleaned from suspended solids and oil products at facilities, and is also discharged into biological ponds or directly into a water receiver (reservoir).
The city may also be supplied drinking water and from underground sources - artesian wells.
An industrial enterprise consumes drinking and process water. Industrial water is most often used in water circulation cycles. For cooling, water is reused after the temperature in the coolers decreases.
Waste water from industrial enterprises containing specific pollution, as well as rain and melt water from the territories of industrial sites, can be discharged into the water disposal system of a settlement and be subjected to biological treatment together with city waste water after passing through local treatment facilities.
Water supply systems of industrial enterprises, depending on water and technological processes, can be direct-flow, repeated (sequential) and reverse. Depending on the technological purpose, water in the circulating water supply system can be subjected to various treatments. In circulating water supply systems, irretrievable water losses (production, evaporation, weathering, splashing, sludge, purge flow) are compensated by an additional, i.e. make-up, amount of fresh water from the source.
Balance schemes for the consumption of water, raw materials, and pollution serve as one of the initial materials in the preparation of environmental passports of an enterprise in accordance with GOST 17.0.04-90 in the section on the characteristics of water consumption, water disposal and water treatment, as well as a passport for the water management of settlements.
Joint schemes for water supply and sanitation of industrial enterprises and populated areas are developed during the design on the basis of a technical and economic comparison of options in order to complete solution water management problems of the district, city or region.
Wastewater treatment is provided through the implementation of the following technical solutions and measures.
Mechanical cleaning - improvement of the hydrodynamic regimes of existing settling facilities; the use of mesh installations instead of settling tanks; pre-treatment of wastewater before clarification with coagulants; expanding the use of technological processes for water purification, using centrifugal forces to separate suspensions and emulsions, instead of gravitational ones; improvement of existing and development of new filter installations.
Chemical cleaning - the use of more active coagulants; improvement of hydrodynamic and mass-transfer characteristics, ensuring the completeness of hydrolysis, mixing, reaction; reuse of slags and sediments of chemical water treatment; isolation and utilization in the main or secondary production of reaction products; organization of a rational wastewater disposal system for industrial wastewater, which ensures their mutual purification after combining at local treatment facilities.
Physical and chemical treatment - expansion and improvement of the processes of hyper-, ultrafiltration, extraction, adsorption, ion exchange, which allow to isolate and return products to the main production, and use purified water after adjusting the composition to standard values in circulating water supply; development and creation of new selective types of sorbents from wastewater for reuse, widespread use of liquid and solid industrial waste in technological processes; the development of low-energy efficient processes, which include the use of electricity obtained from biolysis in water treatment, as well as galvanic coagulation; development of a mobile service network for servicing subscribers for the regeneration of sorbents, electrochemical separation of heavy metals on the cathodes of special installations, which will allow returning products to the technology, regenerating sorbents with the production of secondary raw materials and returning them to the water purification cycle; development of methods for preliminary physical and chemical effects on treated waters; physical treatment (magnetization, ultrasonic, high-frequency), leading to a change in the physico-chemical characteristics and, accordingly, to a deeper degree of pollution from the water.
Biological treatment - application of the method of preliminary anaerobic treatment of wastewater; use of artificial biomass carriers; widespread use of biosorption methods; regulation of the ratio of groups of microorganisms; the use of higher aquatic vegetation (eichornia water or water hyacinth, pistia, calamus, etc.) as an independent phytoreactor for the treatment of wastewater from agricultural complexes with the production of biomass and its use for livestock feed or in the production of biogas; the use of a symbiotic algobacterial community (algae + bacteria) in the treatment and post-treatment of wastewater with artificial lighting during the dark period of the day with an intensity of 120 lux / m. The carbon dioxide produced by bacteria during the oxidation of organic substances is absorbed by algae, and the oxygen released as a result of photosynthesis is used by microorganisms as an electron acceptor in metabolism. This achieves deep wastewater treatment and does not require blowers, compressors for biooxidants.
Currently, the greatest technological and environmental difficulty is not wastewater treatment, but the problem of processing and disposal of their solid phase.
The amount of the formed solid phase at the treatment plant depends on the genesis of the initial composition and consumption of wastewater, the method of their treatment and averages 0.01-3% of the volume. Humidity of the solid phase ranges from 85 (construction industry enterprises) to 99.8% (activated sludge).
The main tasks of the treatment of sludge and sewage sludge are dehydration, disinfection and disposal.
Depending on the ash content, they can be of three types:
predominantly mineral (ash content over 70%);
predominantly organic (ash content less than 30%);
mixed (ash content 30-70%).
At present, there is industrial experience in the return to the main production of wastewater treatment sludge from glass, optical-mechanical, metallurgical enterprises, factories for the production of building products, some chemical industries, and also as additives in auxiliary productions - meat-packing plants; dairies (technical fats, lanolin, fat substitutes); hydrolysis plants (protein-vitamin concentrates); Pulp-cardboard-paper mills (production of wood-fiber boards, cardboard, cellulose).
Sludge disposal is a complex multi-variant problem, the main issue of which is the prevention of secondary pollution of the environment by heavy metals. The most common way to dispose of wastewater treatment sludge is to store them in industrial waste landfills (sludge is treated with cement, bitumen, glass or polymer binders). There is experience in the disposal of heavy metal sludge in the production of building ceramics, bricks, and tiles. Modern environmental approaches to the formation of a wastewater disposal system for electroplating industries take into account the goals of recycling.
When treating wastewater, including galvanic water, it is necessary to increase the one-time costs for the complete separation of flows, which will ultimately increase the environmental friendliness of the technology. In countries with market economy similar approaches have already been implemented 12-15 years ago.
Taking into account the existing experience of a number of countries, in the future we should expect the appearance of treatment facilities with the capture and neutralization of aerosols from aeration bio-oxidants, as well as the placement of treatment facilities in underground workings.

Based on the materials of the book - "Life Safety" Edited by prof. E. A. Arustamova.

The combustible components of the exhaust gases are brought to a temperature above their self-ignition points and they burn in the presence of oxygen present in the exhaust gases.

The main advantage of thermal oxidation is relatively low temperature process, which reduces the cost of manufacturing the combustion chamber and eliminates the formation of nitrogen oxides.

The catalytic method is designed to convert harmful impurities contained in the exhaust gases of industrial emissions into substances that are harmless or less harmful to the environment using special substances - catalysts. Catalysts change the speed and direction of a chemical reaction, such as an oxidation reaction. Platinum, palladium and other noble metals or their compounds (oxides of copper, manganese, etc.) are used as catalysts. The catalyst mass is located in special reactors in the form of a packing of rings, balls, plates or wire, twisted into a spiral, made of nichrome, nickel, aluminum oxide with a micron-thick layer of precious metals deposited on the surface of these elements. Catalytic methods are widely used to remove harmful impurities contained in gas-air emissions from paint shops, as well as to neutralize vehicle exhaust gases.

The main elements of the water management system of the settlement and its interaction with the natural environment are shown in Fig. 7.13.

Water intake facilities take natural water from a surface water source. The pumping station of the first rise through pressure pipelines delivers it to the treatment plant. Here, the water is purified to drinking quality and from the reservoirs the pumping station of the second lift is supplied to the settlement, which, as a rule, has a ring water supply network. Water is used for drinking, household needs, watering streets and plantings, at local industry enterprises.

Used water (wastewater) is diverted outside the city through a closed sewer network and is supplied to the city treatment facilities by the main sewer pumping station.

Here, wastewater undergoes mechanical and biological treatment, disinfected and fed to biological ponds, where it is purified in natural conditions. After the ponds, the water in its qualities differs slightly from the water of a natural reservoir and can be discharged into a river, lake, etc.

Fig.7.13. The main elements of the water management of the settlement and their relationship

The process of urbanization and, in particular, the expansion of public utilities complicates the tasks of urban service organizations. The fight against sewage pollution is especially important in this regard, since the waste from the consumption of household fluids has a direct impact on the hydrological system of the area. As a result, more effective means minimization of negative processes of impact on environment. Today, wastewater treatment is organized taking into account several factors for the elimination of harmful microorganisms. The main method of water treatment is still the arrangement of mechanical filtering stations, but more and more complex installations are appearing that also perform high-quality biological water treatment.

Features of modern wastewater treatment

Engineering equipment is developing in general directions that focus on improving ergonomics and reliability. Therefore, modern sewage drains are multifunctional, efficient and easy to manage. Both industrial and domestic wastewater filtration systems are equipped with control panels with a wide range of settings.

In addition, the developers of sewer and septic systems projects strive to rationalize communication networks as much as possible, optimizing energy resources as well. In other words, wastewater treatment in some nodes can also be connected to complex systems home or business engineering management. And this is not to mention the increase in the basic operational capabilities of cleaning equipment, which is achieved through the use of high-tech

mechanical cleaning

The whole cleaning process is divided into several stages, which have significant technological differences. The stage of mechanical filtration is primary and at the same time multi-stage. The simplest mechanism for such cleaning can be observed on the streets in the form of metal, concrete or plastic gratings that trap debris, leaves, stones and other large elements. In the future, wastewater can be sent through the sewer channel to special centrifuges and hydrocyclones. Also, a special strainer is used to trap microscopic particles - in essence, this is a filtration cleaning station. The drain, thanks to such equipment, can be cleaned of elements up to 0.25 mm in size. Together, the cleaning steps at this point can eliminate about 80% of foreign bodies in the waste fluid.

Biological treatment

Means of this kind of cleaning are usually used as a continuation of mechanical filtration. It can be said that the basic purification by strainers prepares the liquid for deeper processing by biological stations. However, both methods work on different principles. That is, it is wrong to assume that mechanical filtration traps large particles, and biological installations - small ones. The second option focuses on the environmental neutralization of water, which does not cause chemical harm during maintenance and after its release into water bodies. To date, the biological treatment of wastewater, the main goal is the elimination of organic matter or its processing. As a result, the composition of the liquid medium retains only dissolved nitrates and oxygen. In practice, such cleaning is implemented in two ways - natural or artificial. In the first case, the wastewater is dispersed into and into the artificial purification is carried out in special aeration tanks that release environmentally friendly water into reservoirs.

Chemical and thermal cleaning methods

From the point of view of eliminating negative decomposition processes in the wastewater environment, one of the most effective ways is chemical. As a rule, this group of methods is based on redox reactions, which essentially cancel some reactions, replacing them with others that are less environmentally hazardous. But most effective method control of pollution in wastewater is the thermal effect. This method is carried out using furnace installations and burners in which the liquid is burned. Wastewater treatment by the fire method is also practiced without the use of furnace structures. Technologically, this method involves spraying a liquid in a finely dispersed state into a special torch formed during the combustion of gaseous fuel. As a result, water evaporates, which eliminates harmful compounds.

Sludge disposal

New technologies, which ensure the complete elimination of decomposition products, are not yet used at all treatment facilities. Moreover, such a principle does not always justify itself economically. Therefore, traditional cleaning channels are still common, the operation of which leaves sediments. New technologies in such recycling processes manifest themselves at the final stage of waste disposal. In particular, digesters are used. These are massive reinforced concrete tanks in which biogas is formed by fermentation. As a result, methane fuel is formed, which can later be used in boiler houses instead of traditional fuel. Also, complex wastewater treatment with sludge elimination involves the use of mechanical dehydration methods using special devices - centrifuges, belt or chamber pressing plants. In the future, the products of such processing, depending on the chemical composition, can be used in agriculture as a fertilizer.

Conclusion

At this stage in the development of sewer systems, many manufacturers are solving the problem of a complete transition to one of the cleaning methods. This is due to the fact that the technical organization of several stages of contaminated liquid processing is expensive and requires the connection of large resources in the maintenance process. As an alternative, a biological wastewater treatment plant is considered, which also provides for the functions of mechanical processing, but only as auxiliary stages. However, this option cannot be called universal, since biological aerotanks lose in terms of the efficiency of removing harmful particles to the same thermal cleaning. Therefore, it is still advisable to approach the solution of the problem of wastewater treatment through the development of projects that take into account the individual conditions and requirements of the treatment equipment.

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