A serious problem for sewage plant operations is the generation of foul smelling odors, especially when they are located within an enclosed area. Studies have shown that air pollution from odors is the greatest problem that these installations must deal with and for which they receive the most complaints from the local population.
Ozone treatment for deodorization of odiferous gases has been acknowledged as a technically effective method for many years. During the past twenty-five years, hundreds of ozone installations for the treatment of sewage plant odors have been erected. Ozone is one of the strongest oxidants known and quickly breaks down odors compounds.
In the elimination of obnoxious odors', Ozone reacts with malodorous substances to produce oxidized products having better olfactory characteristics. Ozone has been found to be very effective on many contaminants including sulphides, mercaptans, amines, phenols, and similar chemical compounds. In addition, ozone is a very powerful germicide and destroys most airborne bacteria.
Sewage treatment whether it is municipal or from a small colony, poses a great health hazard and cannot be disposed of in any other water body like river, lake or sea nor can it dumped in the land. It can lead to sever health problem to the community and also contaminate the water or the land where it is emptied. This sewage contains harmful chemicals some of which are non-biodegradable and will cause severe environmental degradation. This water has to be treated to the safe level before disposing of. The treatment generally consists of solid particle removal, followed by oxidation in a bio- reactor. The water has to be further treated for disinfection.
In recent years, sophisticated needs for advanced sewage treatment have been increasing for recycling sewage treatment water. Ozonation as part of advanced sewage treatment is assumed to be extremely effective for decolourization, disinfection, deodorization, and reduction of COD because of its strong oxidizing capability.
Eltech, offers an originally developed ozonation system that achieves low running cost and space saving using a highly efficient ozoniser of completely new concept to meet these needs.
Wastes are treated by a variety of sewage treatment processes that are aimed at reducing the biological oxygen demand and removing nutrients that could cause eutrophication of receiving waters.
Sewage treatment can involve physical removal of solids (primary treatment); biological decomposition of organic compounds (secondary treatment); chemical, physical or biological removal of other constituents such as heavy metals, nitrogen, and phosphates (tertiary treatment); and disinfection to remove potentially pathogenic microorganisms.
The purpose of tertiary treatment is to provide a final treatment stage to raise the effluent quality before it is discharged to the receiving environment (sea, river, lake, ground, etc.). More than one tertiary treatment process may be used at any treatment plant. If disinfection is practiced, it is always the final process. It is a so called "effluent polishing."
Ozone is very helpful in the tertiary treatment of the sewage. After the primary treatment which mainly consists of formation of colloidal particles and removal of these along with suspended solids. The secondary treatment is normally a bio–reactor where oxidation takes place with the help of aerobic bacteria. The water still has to be disinfected and chlorine which has been used hitherto is the least desirable chemical today. This is replaced by ozone with added advantage of giving further reduction of colour, odour while disinfecting at the same time. Ozone is also used for the reduction of BOD (biological oxygen demand) and COD (chemical oxygen demand). However, the primary function of using ozone in the tertiary treatment is to disinfect. A minimal dose of ozone does this job better than high dosage of chlorine. The ozone treated water is considered safe to dispose of. In fact, in most of the cases, the ozone treated sewage water is recycled for various uses like gardening, cooling tower water requirement and also for toilet flushing in many housing colonies.
Removes Bad Odour
Improves water quality
Benefits of Ozone in STP
You may consider the following advantages of Ozone over earlier methods of chlorine disinfection to save our Mother nature.
Ozone kills the bacteria and viruses safely and effectively.
Ozone in sufficient concentration will eliminate or greatly reduce the odour and colour in the treated waste water.
Ozone is generated on premises. (No storage, procurement and transport required).
Chlorine, when mixed with organic residues will form– Chloramines/ Chloroform/Trihalomethanes, etc that are toxic to the ecosystem. Ozone when reacts with the organic residues will oxidize the organic molecule in to Co2 and H2O and there is no toxic byproducts produced.
Ozone treatment increases the dissolved oxygen in the water which is very good to the ecological system.
Ozone is the most active oxidizing agent that can be used safely. It is sometimes called "activated oxygen", or enriched oxygen.
Tests have proven that Ozone is 3000 times more active in the destruction of bacteria and viruses than chlorine in the same concentration. Escherichia (E-coli) is destroyed within 15 seconds by ozone at a concentration of 1mg/liter (1 ppm).
The waste water treated by ozone can be used for gardening or toilet flushing since ozone removes the bad odour from the waste water.