The higher the level of development of civilization, the greater the amount of waste it produces. Today, the most pressing issues of our time are: "Where to put sewer drains? How to clean them? What is the treatment of sewer and waste drains?"
Purification of water flowing into the sewer is a process whose purpose is the destruction or destruction of harmful substances and impurities in these waters. Some experts believe that this process is unified, but consists of several stages. Others distinguish each stage of cleaning as an independent method. In any case, a variety of wastewater treatment methods are used for sewage rectification. They are rectified with:
- reagents, chemicals;
- filtration and sedimentation;
- electrolysis;
- oxidation and other physicochemical transformations;
- bacteria, microbes, other microorganisms;
- all methods simultaneously (in stages).
The choice of a specific method depends on the final goal.
Mechanical wastewater treatment methods
The main techniques are filtration and sedimentation. The largest mechanical impurities are removed with the help of grids, the sieve copes with smaller ones.
Then filtered water passes through sand traps, special membranes and septic tanks.
Pollution from the surface is removed with the help of oil, oil or gas traps. Settling together with the use of filters allows 75-95% purification of water from impurities, some of which are suitable for processing.
Chemical wastewater treatment methods
This is the name of the purification method, in which reagents that decompose impurities are introduced into the waste water. From 25% soluble and up to 75% insoluble contaminants are eliminated by this method.
Physico-chemical methods of wastewater treatment
With this cleaning, the most commonly used are:
- Coagulation - "bonding" of fine particles into large formations.
- Oxidation is a reaction in which contaminants “burn out” under the influence of reagents.
- Sorption - reagent absorption of pollutants from wastewater.
- Extraction - extraction of dry substances from water .
The use of sorption, coagulation, extraction and other techniques helps to remove finely dispersed impurities, inorganic impurities, and destroy organics or impurities that are poorly oxidized.
Biological wastewater treatment methods
The essence of this technique is that natural processes are used, as a result of which self-cleaning of water bodies occurs. For the rectification of waste water is often used:
- Biofilters are devices through which water is filtered. Biofilters differ from ordinary ones in that anaerobic microorganisms that oxidize impurities are cultivated on their surface.
- Aerotanks - tanks for water purification, built from reinforced concrete. Here, microorganisms, amoeba and ciliates create sludge during their life, with the help of which they are cleaned. Amoeba, rotifers and other creatures that grow in the silt contribute to the constant rejuvenation of the silty substrate. Biological processes are developing rapidly, as organisms are provided with a constant supply of food - wastewater.
- Biological ponds - artificial structures for water sedimentation, working on the principle of natural self-cleaning. The process involves all organisms living in the pond.
Electrolytic wastewater treatment methods
They are most profitable where waste water is contaminated with a large amount of metal impurities: in the paint and varnish, copper industries, etc. The cleaning process is carried out in special containers.