TARHOKAR Engineering CO 
Contact: (+98 21) 44010038 - 44042776  - 44079459

Sanitary Wastewater Treatment

A sanitary wastewater treatment had design and make to eliminate microbial contamination and treat all contaminating agents. Most of the water which is used in urban and rural communities has been converted into sewage. This wastewater has organic substance, fat, carbohydrate and solid particles that must be treated before it returns to the natural cycle.

The prominent treatment methods in the sanitary wastewater treatment are the use of biological methods, containing aerobic and anaerobic. Removing the suspended solids in sanitary wastewater by physical methods and separation of fat, and after that use of aeration and sedimentation unit are the most type of treatment. By using this package, wastewater can be used to irrigate or discharge into rivers and seas.

In TARHOKAR Engineering company, the wastewater treatment of urban and rural communities is designed, constructed, installed and implemented through structures and packages of metal and concrete and polyethylene.
This company is the executer of various sanitary wastewater packages in different dimensions and could be experience the best use of purging the water by renewable sources of water.
Sanitary Wastewater Treatment by active sludge method

 sanitary wastewater treatment process

 Consumed water in urban life is return to the primary sources in some way, but most of the water which are returned to primary sources aren't like the original quality and substances such as proteins, fats, carbohydrates, detergents soaps or detergents has been added to the water. Therefore, there is a requirement for the use of a sanitary clean-up package to return water to the cycle. Daily consumed water by humans has returned to the natural cycle. Daily consumed water which is return to the natural cycle by humans is called human or sanitary wastewater.

Wastewater is a diluted material which contain 99% of water and 0% of solids, which contain biological compounds and pathogenic bacteria. we can classify the sanitary or municipal wastewater in terms of physical, chemical and biological composition in three groups: strong, moderate and poor.
The color of the urban sanitary or wastewater is gray if it is fresh and it will be dark and black if it is old and dirty. In essence, the smell of wastewater is the same as the gas due to the blasting of organic matter in wastewater compounds under the influence of anaerobic bacteria.

If the sewage (wastewater) is fresh, the smell of it, is similar to lather and, if it is not fresh, it will smell like a rotten egg. Some sanitary treatment process are used to treat an anaerobic unit that has a strong odor.

Table of observed analyzes about the strong sanitary or municipal sewage
Wastewater composition poor moderate strong
Fresh sewage color gray gray gray
Old sewage color blackish blackish blackish
BOD5 200 250 600
COD 400 700 1000
TSS 100 200 300
TKN 15 40 60

Biological process of sanitary wastewater treatment

 A sanitary wastewater treatment in Iran is usually designed and developed based on activated sludge method including EAAS, MBBR, IFAS and A2O. Below is a brief explanation of these methods.

Sanitary wastewater treatment design with EAAS or aeration process is a conventional activated sludge method that does not require initial deposition in this process and will require larger volumes and sizes compared to other methods. Aeration is in the form of a deep sanitary wastewater treatment package.

The design of a sanitary wastewater treatment package with the IFAS process, or the process of mixing the active sludge with a fixed carrier growth, is intended to increase the concentration of the biomass as well as the use of smaller cavity during construction and operation. In this method, heterotrophic bacteria in wastewater, organic matter will be removed, and at the end of the process, the process will increase. The required air for heterotrophic bacteria is supplied by aeration or blower, and is provided by diffusers installed in the hygienic treatment package.


Another method in the design of the sanitary wastewater treatment is to use the MBBR process based on the moving process of adhesive growth, and with the growth of microorganisms on the moving carrier, the occupied space by this package will be less than the aeration process, and also The existence of a uniform load distribution and the lack of need for returning sludge from the sedimentation unit will experience less pressure drop. In this method, the dimensions of the deposition unit of the sanitary wastewater treatment will be smaller than the other processes, which includes the benefits of design.

The design of a sanitary waste water treatment plant A2O process, which is a combination of anaerobic, anoxic or nitrate and aeration methods used to remove nitrogen and nitrate in sanitary or domestic wastewater. This method is more common in sanitary wastewater treatment than other treatment methods.

After selecting each of these treatment processes, wastewater enters the final settling unit (clarifier) and then the chlorination duct to disinfect the fecal coliforms and bacteria. It is necessary to note that one of the disinfection methods which is used in these packages is chlorination, that is cheaper than other methods of disinfection, but is less efficient than removal of microbes and degradation factors.
Surface aeration in sanitary wastewater treatment

Different types of structures in the sanitary wastewater treatment

The wastewater treatment  are designed, constructed, installed and implemented in the TARHOKAR company  in various dimensions such as metal, concrete and polyethylene drainage. Dimensions of the sanitary wastewater treatment package can determine by considering the volume of produced wastewater, hours of operation, urban, industrial, factories, hospitals, hotels, etc., and the use of treated waste water in agriculture, reuse of wastewater and... The ability to discharged into surface waters and other factors.
Sanitary wastewater treatment package by Steel construction

 Effluent of sanitary wastewater treatment

The treated domestic wastewater which are removed from the sanitary treatment package must be capable of being disposed to surface water or used for irrigation in green areas and crops. Iran has issued the following guidelines in this regard.
Wastewater composition Discharge into  absorbing well  Discharge into  surface waters  Agricultural and Irrigation consumptions
 BOD5  30 30 100
COD 60 60 200
TSS  - 40 100
nitrate  10 50 -

In some projects, employers are seeking to use treated sanitary wastewater in their cycles of production, that supplemental systems being added to the sanitation process by considering the water quality. The most common of these systems is the use of ultrafiltration in treated sewage output.

Applications of sanitary wastewater treatment

The sanitary wastewater considered as a renewable resource across the world. By using a sanitary treatment package, fertilizers and highly nutritious compost has been Produced in addition to using treated wastewater in irrigation and agriculture. With little investment in great urban wastewater treatment projects, in addition to supplying electricity to the treatment, it can be connected to the electricity grid of the country.

 With the continuing drought in our beloved country, the use of renewable resources of Urban wastewater is one of the most effective and serious ways to deal with this phenomenon.