Masteco Grup

Housing Sewage Water Treatment Technologies

Water used by humans changes its natural characteristics and quite often such use results in contaminations unsafe in sanitary terms. That is why at all times the issue of sewage water disposal was of great significance for all human settlements; this issue is crucial nowadays as well.

At present the technical progress has made possible high-level solutions of the issue of household waste water disposal and treatment. Modern sewage water treatment plants ensure high degrees of the environment protection. However, there are still such human settlements where unfortunately the centralized sewage water collection and disposal system is totally lacking (similar to the situation in the Medieval Europe). Thus, the issue of waste water disposal and treatment becomes a private problem and the use of autonomous sewage and waste water disposal systems to dispose of waste water in country houses has become quite customary; it should be noted that such autonomous systems provide for the possibility of waste water treatment rather than plain accumulation (which fact makes them different from ordinary catch-pits.

All waste water treatment methodologies used in the autonomous sewage water disposal systems can be subdivided into three main categories: mechanical, chemical and biological. Let us examine each of the above in more detail.

Mechanical water treatment provides for the removal of insoluble slurry and dredges from waste water. A major weakness of this method is that it does not ensure the removal of the dissolved organic contaminations from the water. That is why mechanical water treatment plants or facilities (such as precipitation tanks, sand traps, gratings and sieves) are used in most cases as pre-treatment units prior to the biological treatment plants.

Chemical water treatment provides for the use of diverse reagents, which react with dissolved contaminants and facilitate their solidification and subsequent sedimentation. However, we should point out that such reagents are rather expensive; furthermore, they should be dosed very carefully. This method is used mainly to treat industrial sewage water.

In addition it should be remembered that neither mechanical nor chemical water treatment methods provide a final solution for the principal issue – i.e. disposal of sewage water and waste.

That is why biological waste water treatment is currently believed to be the most efficient water treatment method.

The large amounts of organic matter contained in sewage water is a beneficial nutrient medium for the development of microorganisms (bacteria) which feed on diverse organic substances to support their vital functions. This very specific feature of microorganisms underlies the biological treatment method of household sewage water. Microorganisms breathe, oxidizing the harmful organic substances in the process, which are therefore disintegrated to harmless components. As result, water does not tend to rot any longer; it becomes transparent, with considerably reduced bacterial contamination levels.

Mineralization of organic compounds in waste water is caused by bacteria, which can be subdivided into 2 major groups depending on their attitude to oxygen: the aerobes (i.e. the bacteria consuming the oxygen dissolved in water for their breath) and the anaerobes (the bacteria growing in the absence of free oxygen).

Anaerobic mineralization process (without access of air) takes place in ferroconcrete reservoirs (methane-tanks/digesters, septic tanks, two-level sedimentation tanks), in which organic contaminants are fermented with methane-producing bacteria. A key weakness of the anaerobic water treatment method is the production of bio-gas (methane) and thus the unpleasant smell, which is unsafe (unpleasant) in sanitary terms.

The majority of modern sewage water treatment plants are using aerobic methods. Aerobic mineralization process takes place in sewage farms, percolation beds and biological ponds, channels, on bio-filters and in specialized tanks which are called aeration tanks.

Bio-filters and aeration tanks are particularly convenient for the construction of autonomous (local) sewage water treatment systems. Conditions particularly beneficial for the intensive growth and development of microorganisms are created in such systems artificially.

Let us dwell in more detail on the principles underlying their operation and differences between them.

A bio-filter is a reservoir with a double bottom filled with large-grained filter medium (haydite, slag, gravel, etc.). The waste water goes through the filter medium, leaving on its surface a biological film of microorganism conglomerations disintegrating the organic contaminants contained in waste water.

Aeration tank is a reservoir to which an intensive flow of air is fed (the scientific term to describe this process is ‘aeration’). During the biological treatment, active silt is created in the aeration tank from the slurry of particles with microorganisms growing on them, which are contained in the sewage water. Active silt accelerates and improves considerably the oxidation and thus sewage water treatment, consuming organic matter and bacteria. The microbes contained in water, including the pathogens, are absorbed by the active silt and either die or become to active agents thereof. The aeration tank differs from the bio-filter with a much larger filter surface. And a feed air pump ensures high oxidation capacity. The aeration tank is generally accepted as the most efficient biological treatment method for treatment of farm and household sewage water; such tanks have been used for many years at all major water treatment plants.

Unfortunately, the attempts to manufacture small-sized aeration tanks (to be used as small-sized water treatment plants for country houses or small cottage villages) resulted in too high equipment costs or decreased treatment quality – however, it was true only until recently.

Sewage water treatment plants (SWTP) in TOPAS range were developed using the experience and know-how of large-sized water treatment plants with continuous or interrupted small-bubble aeration technologies. The above processes are combined in such plants. This technical solution is protected with multiple patents.

TOPAS plants are available in a range of standard sizes depending on water consumption and the serviced population size. Here you will find more details on TOPAS water treatment plants, water treatment processes, plant commissioning, etc.

Masteco Grup

Close