Wastewater is one of the troubles of the modern world. We produce such a quantity of effluents that in the absence of their treatment half of the whole world would have every chance to turn into a real sewer. How is this problem solved? The answer is simple - sewage treatment plants. They allow you to turn liquid waste into a relatively safe technical fluid, which can already be returned to natural ecosystems.
If effluents enter water bodies without treatment, the ecosystem is very seriously damaged. To avoid this, several methods for their qualitative neutralization have been developed at once. Of course, the reserves of
fresh water in our country are huge, but nevertheless they are not endless, and therefore we should constantly think about the renewal of this resource.
Why is sewage treatment important?
In recent years, there has been a slight increase in industry and the general standard of living of the population, and all these processes are directly related to the sharply increased amount of wastewater produced by industry and the national economy. That is why sewage treatment plants are becoming extremely important, since the environmental situation not only in our country, but throughout the world depends on them.
What is the reason for the negative impact of effluents on the environment?
The enormous damage caused by liquid household waste is largely due to the fact that they often enter natural reservoirs and other objects of drains in completely uncleaned, original form. They infect wells, other sources of fresh water for the population. Damage from drains can only be minimized if they are settled at special facilities. If the treatment is carried out with an insufficient degree of efficiency, then the bacteria and chemical compounds contained in the effluents can cause irreparable harm to the environment and the health of animals, plants and humans.
Recycling of concrete products and legal regulations
Recycling of concrete products is widely practiced in many European countries. There they began to be interested in this problem for a long time for one simple reason: in these states, the natural reserves of fresh water are significantly limited. However, in our country in recent years, a complete re-use of water has become more widespread, due to which it is possible to significantly reduce the consumption of fresh liquid.
Many communal networks of large cities (especially those where industry is seriously developed) have long been fully converted to this technology. The treatment plant operator is obliged to constantly monitor the quality of treatment by monitoring the degree of contamination of the process fluid with residual contaminants.
Legally, all business entities are required to decontaminate the effluents produced by them, using all possible mechanical and / or other methods. In addition, the law establishes rather stringent measures and norms, which must be followed. Note that ordinary citizens are also responsible for this. It should be noted that the reconstruction of treatment facilities should be carried out in a timely manner, without any delay.
Domestic wastewater treatment
In recent years, many tools have been developed that allow for the full treatment of domestic wastewater, which are formed during the life of an average country house. Note that waters of various origins are “sorted”, since the methodology for their cleaning and decontamination is significantly different.
What are the techniques for cleaning waste water and industrial effluents?
This includes a whole range of measures that allow you to effectively remove a wide variety of substances and compounds from contaminated liquids. There are separate technologies for disinfecting effluent from petroleum products, sewage treatment plants from livestock facilities, etc. Whatever technique is used, it refers to one of the main types:
- Biological scheme.
- Mechanical cleaning (grates with which storm water treatment plants are equipped).
- Physico-chemical technique.
- The method of disinfection of effluents.
Let's look at each of these methods in more detail.
Mechanical way
All wastewater treatment plants use this method, since the fluid must be spared of large mechanical particles that pollute it before entering the departments of finer treatment. In addition, this method is used to remove water from the sediment obtained as a result of other stages of wastewater treatment. For this purpose, the following elements may be used:
- Devices like grids or combs, which are most often equipped with mechanisms for self-cleaning. These are often equipped with sewer collectors.
- Sand trapping elements.
- Membrane Filters
- Sumps of the first order.
- Septic tanks.
The distance between the rods of the primary gratings should be no more than 16 millimeters, since they are used to screen out the coarsest and largest elements (they often fall into sewer collectors). Wastes received at this stage are either crushed, or transported to places where they are buried. Next comes the period of sand traps, which allow you to purify water not only from it, but also from fine glass and other similar impurities.
They are no longer crushed or buried, but taken to long-term storage warehouses. The raw materials that accumulate there are subsequently used in various road works. It is important to note that cleaning of treatment facilities with a mechanical method of deactivation should be carried out as regularly as possible, since otherwise their effectiveness drops sharply, trapping devices begin to let in too many contaminants.
The most promising technique is the
treatment of effluents using
membrane filters. This allows you to deactivate the waste to such an extent that in some cases it can be returned back to the production cycle. It should be remembered that the mechanical method allows sifting no more than 70% of all types of contaminants, so that the treatment plants are not limited to it.
Biological technique
Almost any wastewater is seeded by various types of microscopic organisms. In biological methods, nitrogen and phosphorus, as well as anaerobic and aerobic bacteria, can be removed from drains. Very often, this technique uses biological fermentation technology, activated sludge, as well as fine biological filters. How do biological treatment plants work?
First, the water goes to the first order sumps. There, organic suspension is precipitated, and the smallest particles are absorbed. In the secondary sedimentation tanks, the accumulated sludge is removed using special pumps. In principle, such a system can be equipped with almost every household suburban area.
So, today there are ready-made complex facilities for sale that allow biological and mechanical cleaning of concrete products. Their main value is ease of use and the absence of the need for frequent maintenance. Water after passing through the system of such purification does not have a smell or taste; it can be safely used for various household needs, including drinking domestic animals.
The most expensive and effective models include an ultraviolet disinfection unit. After this treatment, water can be completely discharged even into natural bodies of water. The efficiency of deactivation of reinforced concrete in such systems is at the level of industrial solutions.
Physicochemical method
In this case, a combined technology is used, which includes the following methods:
- Evaporation
- Wastewater treatment using ozonation.
- The introduction of chlorine compounds.
- Electroflotation.
Such techniques are very much in demand at the enterprises for the production of oil refining products, since extremely strict methods have been developed for them that control the effectiveness of the refining performed. In recent years, similar drainage systems are becoming more widespread in a private environment, for ordinary country houses. It is important to remember that uncontrolled application of such techniques in your area is strongly discouraged. The fact is that with this technique a lot of chemicals are used that can cause significant harm to both your health and the health of pets and plants.
The most promising and effective in these conditions have proved themselves to be the cleaning of concrete products using electric pulses, as well as ultrasound and ultraviolet radiation. In this case, there is only one drawback - the very high cost of such equipment, which makes it inaccessible to many owners of suburban areas.
Wastewater disinfection
Before sending purified liquid to natural reservoirs, it is necessary to carry out its complete disinfection and decontamination. For these purposes, in recent years, ultraviolet has been most often used, but the use of “classical” chlorine is not excluded. It must be remembered that the operation of treatment facilities involves their location on the leeward side of any housing or community. In addition, the site for their placement must necessarily have a slope, due to which the drains will be removed naturally, without the need for special pumps. This is especially important when urban wastewater systems are being designed.
Important! When designing such structures, it is worth considering the slightest possibility of flooding the site with ground and / or sewage. Wastewater treatment plants include the following equipment:
- Devices for the uniform distribution of wastewater (in particular, storm water treatment plants work this way).
- Devices that allow automatic self-removal of excess contaminants from trapping devices.
- Equipment that allows emergency discharge of excess effluent.
- Devices that measure the physical and chemical characteristics of effluents and their precipitation.
- If necessary, installations that carry out automatic sampling can be used.
Disinfection of domestic wastewater
To perform effective treatment of domestic wastewater, the following conditions must be fully met:
- The right choice of technology to be used for this purpose.
- Selection of the most effective equipment for the highest quality liquid purification from the widest range of contaminants.
- Absolute adherence to the technology recommended by the manufacturer.
Only with a responsible and economically viable approach to the selection of cleaning systems will they be practical. The higher the degree of decontamination of effluents, the more fully they can be reused in production, significantly saving company funds. Flotation and membrane filters have proved to be most attractive in this respect, since they fully meet several important conditions at once:
- High versatility, thanks to which these water treatment plants are able to delay almost all types of pollution.
- Their effectiveness reaches 99.5%.
- Small footprint required for installation and low maintenance cost.
- Easy installation and the ability to install additional modules that can significantly expand the functionality of the installation.
About collectors
Any project of sewage treatment plants of an external type must comply with SNiP 2.04.03-85. The basic principle of their laying is hierarchical: all small networks are connected to larger collectors. If possible, the pipe laying is carried out so that the liquid can drain by gravity along them. For urban sewer networks, the hierarchy is as follows:
- Yard and quarter plots, the diameter of which is 150-200 mm. Their peculiarity is that when laying these structures they are never taken outside the streets.
- Street type collectors, their diameter is 250-400 mm. On the contrary, they are just being built in the streets, and in some cases they can be equipped with compact pumping stations.
- District collectors. Their diameter can be about 500-1000 mm. They are built for entire urban areas and without fail equipped with pumping stations.
- Collectors of urban importance. Diameter - 1000-5000 mm. They are built around the perimeter of the city in the most lowered areas.
Throughout the sewer network, inspection wells from reinforced concrete rings with a diameter of 1 meter are necessarily built (their depth is up to six meters). In some cases, one and a half meter rings are used, the depth of the well under this condition is up to six meters. Their step is calculated according to SNiP 2.04.03-85. For example, during the construction of a domestic sewer network with a diameter of collectors of 150-200 mm, the step between them should not be more:
- At 150 mm - 35 meters.
- More than 150 mm - 50 meters.
We hope that the information obtained from this article was useful to you.