Considering the huge volume of human sanitary sewage in the world today, wastewater treatment has become very important; Because its discharge can cause irreparable damage to the environment, and on the other hand, if human sanitary wastewater treatment is carried out, it can contribute greatly to the water shortage crisis and agricultural and economic prosperity in every Please be a country. Human sanitary sewage is produced by humans as a result of daily water consumption to perform daily sanitary tasks such as bathing, washing clothes, washing dishes and cleaning, etc.

Human sanitary wastewater treatment methods

Three general methods can be used for wastewater treatment. These three methods are:

Physical method

This method is one of the first methods in the treatment of sanitary waste water, and due to the simplicity of the process, it is used in the separation of materials. The physical method is less expensive than other methods, that’s why this purification method is used most of the time. This method includes: garbage removal, granulation, sedimentation, filtration, degreasing and flotation.

Chemical method

This method is more complicated than the physical method. In the chemical method, the process of separation or conversion of materials takes place using substances and chemical reactions. The complexity of this method has made it more difficult to use the chemical method and as a result less of this process is used in the purification system. Another problem of this method is the high cost of purchasing and maintaining chemicals, which prevents the use of this method in the purification system. This method includes: ozonation, chlorination, pH adjustment, coagulation and flocculation, and disinfection with chlorine.

Biological method

In this method, micro-organisms, especially bacteria, are used in the treatment of human sanitary wastewater; Because the organic materials in it absorb the waste water and use it for cell proliferation and energy. As you know, organic materials make up the majority of pollutants and make the use of biological methods common. This method with a very low cost can purify a major share of pollutants, which includes: aerobic and anaerobic.

Considering that it is not possible to purify wastewater using one of the mentioned methods alone, a combination of all the above methods is used in the purification of human wastewater.

Human wastewater treatment system processes

As we said, the biological method by combining two other methods is one of the common methods in purification, which takes place in the initial stages of purification, disinfection and pre-purification; That is why the biological method is mostly used. Garbage of coarse particles in sewage is usually done by the garbage collection unit. This is done to prevent clogging of pipes.

Garbage collectors are made in different sizes and capacities according to the droplets of passing particles, wastewater flow rate, wastewater pH, whether it is manual or mechanical, and site conditions. EAAS select activated sludge system that has extensive aeration as one of the best methods for system aeration. Sludge disposal is one of the problems of wastewater treatment plants, and this has caused the activated sludge system to be paid more attention; Because it produces less sludge than other systems.

Disinfection must be done after using this system. The disinfection process is done to prevent germs and diseases from entering water sources.

Quality of sanitary sewage:

Due to the origin of wastewater production (human activity), it has almost the same quality all over the world, human sanitary wastewater is the result of the combination of black water (toilet) and gray water (bathing, washing dishes, washing clothes, etc.) in the country. The developed facilities of these two parts are separated from each other so that the purification steps can be done more easily; But in Iran, both of them enter a common sewage network and must be treated as sewage under the human sewage treatment system.

The quality of wastewater depends on factors such as the level of health, culture, welfare and many other factors that make them slightly different from each other; But all of them are within a limited range of pollutants and can be referred to for the construction of a wastewater treatment unit.

The qualitative analysis of human wastewater in Iran, if no test is performed on it, is considered for the design of a sanitary wastewater treatment system unit according to the table below.

Sanitary wastewater production per capita:

To build a treatment unit, we need wastewater production per capita. The volume of wastewater produced per person during the day is called per capita wastewater production. The production per capita is not the same everywhere and depends on many factors such as the level of health, culture, weather conditions, consumption pattern, land use, etc. The amount of wastewater produced by a complex can also be estimated from the water consumption bill. If the bill is not available, this per capita can be estimated in different uses in Iran according to the table below.

Features of human sewage treatment system

Today, human sewage treatment systems are used in all developed and developing countries and even in war-torn countries such as Afghanistan and Iraq. These countries are customers of these production systems of Iranian companies. The advantages of human sanitary sewage treatment devices are:

• Suitable efficiency and obtaining the standard approval of the Environmental Protection Organization