Chemical method wastewater treatment is usually used for industrial production where water is polluted as a result of activities various substances. In order to remove various impurities from contaminated water, special reagents are added to it, which help to form poorly soluble substances that precipitate. The chemical cleaning method also involves disinfecting already purified water using chlorine-containing reagents that destroy pathogens.

Mechanical wastewater treatment

Mechanical wastewater treatment helps remove large debris and particles of mineral origin that are in the effluent in an undissolved suspended state. During mechanical treatment, wastewater passes through sand traps, grates and special filters, then it settles in a settling tank, where it is partially filtered and clarified. This method applied immediately before biological treatment.

Biological sewage treatment

Biological treatment is designed to free wastewater from organic compounds dissolved in it. Special groups of microorganisms take part in this process: aerobes, which develop only in the presence of oxygen in wastewater, and anaerobes, which require oxygen deficiency. Accordingly, purification can be aerobic or anaerobic. In modern wastewater treatment plants A combination of anaerobic and aerobic cleaning is used, which gives remarkable results.

Aerobic cleaning occurs in aeration tanks, in septic tanks with a biofilter, in filtration and absorption fields, in filter wells with natural and forced air supply. Forced air flow is created in treatment plants using compressors. In all other cases, oxygen comes from the surrounding air. This chemical element is the main one in the life processes of aerobic bacteria. In the presence of oxygen, aerobes begin to actively multiply and feed on organic pollutants, resulting in intensive wastewater purification. In parallel, there is formation activated sludge in purified water. Activated sludge is a very useful substance, as it mixes with sewage and causes oxidation processes of dangerous organic compounds, turning them into simple and harmless components. As a result, the water is freed from bacterial contaminants, becomes transparent, and loses the unpleasant smell of sewage.

The advantage of aerobic cleaning is practically complete cleansing organic wastewater. Anaerobic cleaning occurs without air access. For this purpose, special closed tanks are made where oxygen deficiency is created.

Such conditions are favorable for anaerobic bacteria, which are involved in the fermentation and decomposition of organic matter into water, methane, carbon dioxide and other simple compounds. Anaerobic treatment takes place in septic tanks, digesters and special two-tier settling tanks.

• Heating pipes with a heating cable and other insulation methods

Human activity, like that of any other living creature, is certainly accompanied by the release of a considerable amount of waste. IN modern conditions Almost all of them are carried away into the distance by the waters of sewer rivers. Finally, it is almost impossible to imagine our civilization without a huge number of factories and other enterprises, which also produce large amounts of wastewater.

About the wastewater treatment process

Wastewater treatment is a process after which the wastewater is suitable for use for technical purposes or for return to environment without prejudice to the latter. In short, the method depends on the further use of the liquid. For example, wastewater from sinks is not the same as the contents of the drain pits where the contents of the toilet are discharged.

Why is this so important?

In April 1993, more than 400,000 people in Milwaukee were hospitalized as a result of cryptosporidium in their drinking water. After this incident, which received a powerful response from WHO, the world community began to be much more careful about the liquid that flows from taps under the guise of “ drinking water" This opinion only became stronger after the publication of some cases of epidemics in India, as a result of which hundreds of people died. But it was a matter of ordinary E. coli that got into the water supply from poorly treated wastewater! So wastewater treatment is an extremely important process that saves people's lives and health.

Any contaminants radically change the taste, color and smell of the liquid, not to mention its suitability for food or technical purposes. The most dangerous are industrial effluents, since they often contain concentrations of heavy metals and other substances that are tens and hundreds of times higher than the most “optimistic” MPCs. Of course, in this case everything depends on the specific production that discharges wastewater. The sewer system of an average city may seem like a “spring” in comparison, since at least it does not contain radioactive isotopes or huge amounts of heavy metals.

Classification of waste

Dangerous contaminants that make water unsuitable for drinking and domestic use can be classified as physical, chemical, biological factors. The release of radioactive isotopes stands out. Accordingly, the classification of pollution will be identical to the reasons that cause it:

• Mechanical factors. They are characterized by a sharp increase in the smallest mechanical suspension in the liquid.
• Chemical. The water contains an increased content of any chemical compounds. It does not matter whether these substances can have a negative effect on the health of the human body.
• Biological and bacteriological (domestic wastewater). Very dangerous look pollution, since in this case the content of microorganisms in the water is exceeded. At the very beginning of the article, we already said what this entails.
• Thermal pollution. This is the name given to the discharge of water from cooling ponds at thermal power plants and nuclear power plants into rivers and other bodies of water. This species should not be taken lightly, since such phenomena lead to the mass death of endemic species adapted to the low water temperatures that are characteristic of our area.
• Radioactive. Radioactive isotopes are found in water and bottom sediments. This happens when the wastewater system at some industrial plants or nuclear power plants is faulty.

Characteristics of the main types of waste

In our conditions, three types of wastewater are most common:

• Impurities of inorganic origin, including even non-toxic compounds.
• Substances of organic origin.
• Mixed effluents.

Waste from metallurgical production is very dangerous, as it contains huge amounts of heavy metals and other toxic compounds. They cheat physical properties water. In those bodies of water where this poison enters, all living things die, including trees and other vegetation along the banks. Organics are dumped by oil refineries and similar industries. The wastewater contains not only relatively safe oil, but also extremely toxic phenols and similar substances. In addition, livestock-type enterprises should not be discounted.

They throw out a huge amount of organic matter. The latter causes a sharp deterioration in the organoleptic properties of water. In reservoirs where wastewater from enterprises ends up, there is a sharp development of microscopic algae, blooming, and the oxygen content in the liquid drops to a minimum. Fish and other aquatic organisms die. Electronics production, including etching of printed circuit boards and production of radio engineering products various types, produces mixed type effluents. They contain dyes, heavy metals, acetone, phenols and other compounds.

Danger of oil products getting into water

Currently, scientists around the world are sounding the alarm as gigantic amounts of oil are leaking into the World Ocean. It forms a thin film on the surface of the water, which can sometimes be seen only by rainbow stains. This not only leads to a significant deterioration in the organoleptic properties of the liquid, but also to a sharp decrease in the supply of oxygen, which enters the ocean through diffusion. Again, aquatic organisms suffer, and the lack of this substance especially affects corals, the number of which in the seas and oceans is falling catastrophically every year. Just 10 mg of oil and petroleum products make water absolutely unsuitable for drinking and living beings.

Phenols, which we have repeatedly mentioned above, are extremely dangerous. They are present in the wastewater of almost all industrial enterprises. This especially applies to those of them involved in the production of coke. In the presence of these substances, mass death of the inhabitants of ponds, rivers, seas and oceans occurs, and the water itself acquires an extremely unpleasant, putrid odor.

What substances do they contain?

The following effluents enter wastewater treatment plants:

• Proteins - 28%.
• Carbohydrates - 17.5%.
• Fatty acids - 10%.
• Oils, fats - 27%.
• Detergents - 7%.

As you can see, the main share of pollutants is organic matter. In industrial conditions, it is pointless to discuss any particular composition of wastewater, since in each case it is different. In particular, in some cases, supposedly purified “water” is dumped directly into the river (!), which in appearance and composition resembles used motor oil.

Main sources of pollution

As a rule, industrial and industrial sectors are to blame for environmental pollution. social facilities, as well as livestock and poultry farms. Solid waste that is generated during open-pit mining of mineral deposits, as well as wastewater generated during wood processing, is very dangerous. Water and rail transport generate a lot of biological waste. When released into water sources, they cause contamination with E. coli or worm eggs. It is especially dangerous when there is some kind of medical facility upstream of the river.

General information about the cleaning process

Processing includes the following methods:

• Mechanical. This includes filtration, which all wastewater treatment plants use, as well as sedimentation.
• Physical. These are electrolysis, aeration, and treatment of wastewater with ultraviolet radiation.
• Chemical methods. Special compounds are used to precipitate and disinfect substances that may be contained in wastewater.
• Biological wastewater treatment. In this case, plants that assimilate organic matter are used, as well as some types of protozoa, snails and fish.

General processing

Before processing begins, preparatory work is carried out. More precisely, wastewater analysis. Chemical laboratory specialists determine exactly what pollutants they contain. This helps you choose best strategy to neutralize them. General procedure Wastewater treatment involves screening out: solids, bacteria, algae, plants, inorganic impurities and organic matter. Removing solids is the easiest step. It involves filtration and sedimentation by settling. It is much more difficult to purify wastewater from thin suspensions that are not retained by conventional filter materials.

One of the simplest and cheapest methods, which nevertheless provides a high degree of purification, is the use of activated carbon. Filters with this material are used in almost all enterprises whose management takes environmental protection seriously.

How does activated carbon work?

The main advantage of coal is its high absorption capacity. Simply put, on the surface of the particles of this substance there are such a number of pores that they can retain such an amount of water polluting compounds, which is several times greater than the volume of the coal itself. It is the process of trapping and binding polluting reagents that is called absorption. It should be noted that coal was used to purify drinking water even before our era. Active research and production of this material began during the two world wars. Factors affecting absorption are particle size, surface area, structure of the bound substance, acidity of the medium (pH factor), temperature of the wastewater.

What substances can activated carbon bind?

Charcoal absorbs many substances, ranging from non-ferrous metals to complex organic compounds (for example, phenols). Of course, it will not protect against radioactive compounds, but the main types of inorganic and organic impurities can be removed with its help.

Coagulation of pollutants

In some cases, special liquids containing particles of colloidal substances can be used for cleaning. What are they needed for? It's simple - microscopic particles, combining with molecules of pollutants, cause them to precipitate. The phenomenon is known as coagulation. Some treatment plants also use electrolysis. The method is similar to the previous one, since the ions produced during this process also contribute to the precipitation of contaminants.

In contrast, modern researchers are increasingly proposing methods that use bulky molecules that can bind and precipitate pollutants more efficiently. This process is called flocculation.

Chemical compounds used

More about the settling method

Be that as it may, the bound organic matter falls out in the form of flakes or gel. These sewage sludges can be easily captured using a simple mechanical filter. This method works best with relatively dense particles (such as silt and other heavy organic matter), while lighter particles (such as microscopic algae) are better removed by settling. The settling tank must be large enough so that it fills as slowly as possible. This is due to the fact that the normal process requires at least four hours. Once organic and not organic impurities will settle to the bottom, the water can be considered conditionally purified and suitable for use for technical purposes. This method is more often used for pre-treatment of wastewater.

Then comes the turn of aeration. The water enters giant vats, where it enters compressed air under high pressure, released into the liquid through sprayers. Have you ever seen how a compressor works in a regular aquarium? In this case, almost the same thing happens. Aeration allows you to saturate the water with oxygen and remove remaining organic impurities into sediment. After such treatment, the liquid is most often supplied to special ponds planted with higher aquatic vegetation (biological wastewater treatment). And only then is the water considered suitable for use for technical purposes. It can be used to water plantings of vegetables and fruits, and also be thrown into natural bodies of water.

Drainage systems are a necessary component of any private household. The sewerage system is initially designed in such a way that it prevents the formation of traffic jams and blockages, which create an unpleasant odor and can disrupt the drainage system. For this purpose, the sewerage system is supplemented with special devices that provide pipes. If such infrastructure is properly designed and installed, it will last for many years without accidents.

Sewage device

Today, the main materials for the implementation of drainage systems on the site are plastic pipes(PVC) high density. They have become popular due to their lightness and resistance to corrosion processes, and their strength under these operating conditions is not inferior to their metal counterparts. In addition, sewage cleaning products are easier to implement in such systems. However, it is also advisable to use cast iron pipes, but they are more expensive.

IN ready-made system At the site, water moves through the pipes independently. To ensure gravity flow, pipes are laid at a certain slope. Typically, the sewer system acts as a connecting element between wastewater collection areas and an external reservoir or collector.

Mechanical method of removing blockages

A tool for performing cleaning operations using this method can be found in every home - this is a plunger and plumbing cable. Before using these devices, you should try removing traffic jams with boiling water. It has a good effect on those that cause pipe clogging. If this method does not help, you can use a plunger. Using simple manipulations, the sewer system is cleaned, the pipes of which must first be filled with water, otherwise the effect will be minimal.

The plumbing cable has a special handle for rotation and a spiral tip. There are also models with ends in the form of a brush and brush. But it is important to remember that cleaning sewer pipes too roughly with hard elements can damage some types of rubber and plastic products. During cleaning, you can intuitively determine the nature of the blockage - as a rule, the cable allows you to physically remove plugs of any complexity.

Chemical cleaning

Application in the maintenance of plumbing communications chemicals Not unusual. They are effective and easy to use, but you should follow the instructions for use to avoid burns.

Besides folk recipes in the form of soda and vinegar, you can try special drugs based on alkali and sodium hydroxide. The advantage of this combination is the effective cleaning of sewers by dissolving all common types of salts, acids and fats, the concentration of which provokes the formation of traffic jams. The disadvantages of such a chemical include the risk of damage to PVC pipes. But the drug is allowed for maintenance. Specialized compounds used for plastic sewers are developed on the basis of hydrochloric acid. Such products cope with limescale formations, grease, remove hair and food residues.

Hydrodynamic sewer cleaning

This modern method getting rid of blockages in sewer pipes, which is more often used in private homes. The operating principle of this technology is based on water exposure high pressure. Accordingly, hydrodynamic sewer cleaning involves the use of special equipment. Several years ago, similar operations involved complex installations on a car chassis. On this moment development plumbing equipment makes it possible to produce small-sized hydrodynamic units that can easily remove plugs in pipes with a diameter of 5 cm or more. The speed of removing blockages is determined by the power of the machine.

Absorbent wells and ground filtration

IN Lately such wells have become the most popular for ensuring the drainage of storm sewers. By design, this structure is a concrete (or plastic) ring-shaped system with a diameter of 1 m, immersed in the ground. Direct cleaning is carried out using drainage flooring, including sand, gravel or sand-gravel layers. Top part the absorbent well is covered with geotextiles. When constructing such a structure, it is important to follow the rules for the location of septic tanks - the minimum distance from the house is 2 m.

Cleaning with natural materials and the participation of the soil layer does not seem difficult to install and provides good results when filtering. To understand its operation, it should be recalled that the wastewater first enters a special settling tank, where it settles, is separated and undergoes fermentation. Next comes cleaning in the ground. At this stage, the principle of ground filtration is carried out. The system uses a layer of washed crushed stone and geotextiles. The rest of the infrastructure is also made of drainage pipes and connecting components. During the purification process, organic and mineral elements are dissolved - at this stage, bacteria are retained, and the filtered effluent passes further to groundwater.

Biological treatment of septic tank

If the conditions on the site do not allow the implementation of a purification system based on natural filtration principles, then there is only one option left - installing a biological septic tank, for example, an aerobic one. In most cases, sewage systems where wastewater is treated in this way last longer precisely due to high-quality pre-filtration.

The object is located underground and in finished form It is a closed container divided into chambers. One of them provides for the presence of a frame with useful (in terms of filtration) aerobic bacteria. Using a special compressor, air is supplied to the septic tank, which is sprayed by a diffuser. This is how biological wastewater treatment occurs through fine-bubble aeration.

In suburban households, it is advisable to use this approach if it is intended permanent residence. This is due to the fact that aerobic septic tanks use activated sludge, which, in the absence of wastewater, loses its functional qualities.

Reservoirs and ponds in the sewerage system

The collection of rain and melt water can also be organized in an artificial reservoir, after which it can be used for watering the site. In addition, some of the wastewater will naturally evaporate. The slopes and bottom of the reservoir must be provided with waterproofing.

If the soil surface is poorly permeable (there is a layer of clay with silt), then water resistance will remain without third-party intervention. If the bottom and walls of the reservoir are made of sand, you will have to create artificial layers of insulation - you can use the same clay or sealed film. It happens that a sewerage system is installed in an area with high groundwater. For this reason, during periods of intense rainfall, it is important to monitor the level of the reservoir - it should not overflow.

Where to locate the treatment plant?

The best option would be a flat and free area on which to mark low level water and permeable soil. This ideal conditions to create clearing drainage. But in most cases, you have to deal with problem areas, which, in fact, determines the variety of approaches to wastewater filtration.

When planning where to install a drainage or septic tank, it is important to consider the configuration in which the sewerage system is installed. Cleaning should eliminate the risk of contamination of drinking wells and residential facilities. To minimize this likelihood, it is advisable to leave a few meters from the structure to the toilet, garden and house. As a last resort, it is necessary to ensure the reliability of the filtration system itself.

Uncontrolled release of wastewater provokes irreparable environmental consequences.

Peculiarities

According to its structure, the wastewater drainage network industrial enterprise much more complicated than ordinary sewerage in a private or even apartment building. The components of an industrial sewer system are as follows.

Communication network for the disposal of domestic and fecal waters.

Waste water network from production.

Disposal of clean and conditionally clean wastewater (storm drainage).

Large enterprises have their own treatment complexes, taking into account the specifics of production. For example, effluent from tanneries must sit for a long time to prevent the waste from clogging the city sewer system. Wastewater from chemical plants is treated to avoid environmental pollution.

Cleaning sewers at an industrial enterprise is a difficult and lengthy process. Small enterprises do not have permanent treatment plants. Wastewater is discharged into settling tanks, then using the services of companies equipped with special equipment. This equipment is very convenient and maneuverable; it can work on sites with inconvenient access roads, as well as pump out wastewater from considerable depths. The use of a vacuum loader is an environmentally friendly process, since the loader pumps out all wastewater, including those with hazardous impurities.

Thus, some kind of standard standard scheme There is no industrial sewerage. When designing a sewer network, engineers need to consider the following factors.

Wastewater volume.

The nature of the wastewater.

Chemical composition and temperature. . Possibility of reuse in production.

Potential for extracting valuable chemicals.

Methods and degree of purification.

Most often, industrial sewerage is connected to a centralized city system. This is one of the most profitable options. By diluting industrial wastewater with domestic wastewater, subsequent treatment becomes much easier. However, the discharge of industrial wastewater into city sewers is strictly regulated. For this reason it is so important right choice and installation of treatment facilities. If in wastewater contains only inorganic impurities, it is advisable to collect them in special containers. After settling, they are suitable for reuse in production process. Some enterprises have installed installations that make it possible to extract valuable substances from wastewater (wool fat, non-ferrous metals, etc.). As a rule, membrane treatment is used, which allows solving two problems simultaneously: high-quality wastewater purification and obtaining valuable raw materials that can be put back into production.

Storm sewer

The tasks of “storm drains” at industrial enterprises boil down to the following.

• . Roof water drainage.
• . Collection of water from washing complexes.
• . Accumulation of water coming from roads.

The storm sewer system of an industrial enterprise can be connected to the citywide network if the water does not contain insoluble inorganic impurities and similar chemical compounds. If water contains insoluble impurities, it must be mechanically purified. If the throughput of the city sewer network is poor, special tanks are installed on the territory of the enterprise, from which wastewater is uniformly discharged into the general network.

Operating modes

There are 2 types of modes of industrial sewer systems.

Gravity - using the natural terrain to transport wastewater. The main advantage of this method of transportation is minimal energy consumption.

Pressure - transportation of wastewater to treatment devices and further to the discharge point is carried out using pumps.

The specifics of the work of many enterprises do not allow choosing any particular mode. Most often, there is a combination of both methods of wastewater disposal.

Care issues

Sewer cleaning - actual question for all industries, and there can be no exceptions here. Lack of careful care can lead to unpredictable consequences. The specifics of cleaning are as follows.

The effluents of most enterprises contain toxic and suspended organic matter. This means that it is impossible to do without specialized equipment that professional companies are equipped with.

The work of cleaning an industrial sewer system is an individual, non-standard process. Wastewater has different chemical composition, and under no circumstances should they be mixed. In each case, it is necessary to develop an individual cleaning algorithm. Basics of a professional approach to sewer cleaning In order for the enterprise to function stably and not be idle, preventive sewer cleaning must be carried out at least once a year. If everything is done correctly, the risk of blockages is minimal. On the contrary, if prevention is neglected, the settling of dirt and industrial waste on the pipes gradually leads to a complete loss of their permeability. One-time removal of a blockage is only a half-measure. A professional approach involves eliminating the exact cause of the blockage.

All cleaning activities are divided into 2 large groups.

Urgent (clearing an already formed blockage).

Preventive (the patency of the pipes is still only partially impaired).

The work differs from each other in speed and degree of efficiency. Prevention can take several days, while the time frame for emergency clearance of a blockage is much more compressed.

Cleaning methods

Chemical, thermochemical. Involves the use of synthetic compounds to dissolve blockages. The method is highly effective, but the wrong selection of chemicals can lead to damage to the pipes (thinning or even loss of integrity).

Mechanical. It is used when blockages are too strong or if the blockage is caused by a foreign object getting into the pipe. For mechanical cleaning, a cable with an attachment is used.

Hydrodynamic. Elimination of blockages is carried out with a water jet, which is supplied under strong pressure. The pressure value is 150-300 atmospheres.

Depending on the size of the blockage, the pressure value and the type of nozzle are selected. This is an effective and, at the same time, gentle method that gives good results even with low temperatures. The risk of damage to pipes, regardless of the material of manufacture, is almost zero. . Pneumohydropulse.

Hydrodynamics

When cleaning drainage systems, special hydrodynamic machines are used. There are 2 types of hydrodynamic machines.

Powerful units that are moved by trucks.

Small devices for internal sewerage.

Equipment configurations depend on the specific model, manufacturer and price segment. However, any model includes a water tank, a system of hoses and nozzles. The correct selection of one or another nozzle makes it possible to effectively clean the pipe from contamination.

There are different types of nozzles.

. "Chain carousel". With its help, it is possible to remove foreign objects that have fallen into the sewer. . Bottom nozzles - clean pipes from silt and sand.

Punching - used to eliminate neglected contaminants.

Rotary - for removing fat deposits.

Complex - a universal option. It is used to eliminate various types of pollution.

Chemical, thermochemical methods Thermal method(dissolving the blockage hot water) is especially effective for eliminating fat plugs. It is also used when cleaning storm drains in the cold season. Cannot be used if pipes are made of PP and PVC. Chemical method involves the use of certified chemicals, which, for greater efficiency, are pre-foamed using special equipment. In addition to cleaning agents, chemical compounds with a disinfecting effect are simultaneously used.

Pneumohydropulse method

It is efficient and environmentally friendly clean way. Carried out using special equipment. Short, numerous pulses are supplied to the pipeline. When a sound wave passes through a liquid medium, cavitation bubbles are formed. When the bubbles collapse, a shock wave is formed, the power of which is sufficient to tear off particles of contamination from the pipe. The power of the device is enough to remove any blockages and dirt. The machines are also equipped with special sludge pumps and tanks with a capacity of about 14 thousand liters, which makes it possible to clean pipes on a very large scale. Comprehensive work to eliminate blockages involves the use of at least two types of cleaning. One is to directly remove the blockage, the other is to eliminate the root cause.

When choosing a particular technique, such factors are taken into account.

Dimensions of the blockage. . The material from which the pipes are made.

Degree of wear and tear of communications.

Cleaning the sewer is a task that requires special knowledge and skills. Therefore, maintenance of industrial drainage systems should be entrusted to professionals.

Updated: June 29, 2017