Investigating the types of important pollutants in industrial and sanitary wastewater

 In this article, the types of important pollutants in industrial and sanitary wastewater are investigated. Due to the increase in the population growth rate in the world, the attention to energy consumption control has increased. The increase in production capacity occurs in order to respond to the growing consumer demand, and this has caused humans to inevitably have significant effects on the environment. One of the negative effects of human activities on our planet is the discharge of wastewater from manufacturing industries and urban sources. All these factors have caused the need to develop new technologies and improve existing technologies in industrial and sanitary wastewater treatment. To achieve the best results in this process, theoretical studies and experience are recommended. For this reason, as one of the theoretical materials available in this field, we examine the types of important pollutants in industrial and sanitary wastewater.

Important pollutants in industrial and sanitary wastewater

• Suspended solids
• Biodegradable organic matter
• Pathogenic agents
• Nutrients
• Primary pollutants
• Resistant organic materials
• Heavy metals
• Soluble inorganic substances

The reasons for the importance of removing all types of pollutants separately

Suspended solids

If the untreated wastewater is discharged into the aquatic environment, the suspended solids in it can cause sludge deposits and anemic conditions, so the dissolved oxygen in the water decreases and the water becomes polluted. The volume of sludge produced in treatment plants is directly related to the total suspended solids in the wastewater. Industrial wastewater may contain higher concentrations of suspended solids than sanitary wastewater. Increasing the removal of suspended solids in wastewater as well as reducing BOD of wastewater are the main factors in determining the appropriate method for wastewater treatment.

Biodegradable organic matter

Biodegradable substances, which mainly include proteins, carbohydrates and fats, are always measured in terms of BOD and COD. The higher the amount of biodegradable organic matter in the wastewater, the higher the BOD of the wastewater. This means that microorganisms need more dissolved oxygen for the biochemical oxidation of organic substances, so if substances enter the environment in an untreated form, their biological stabilization can lead to a decrease in natural oxygen sources and create infectious conditions.

Pathogenic organisms

Infectious diseases may be transmitted through pathogenic organisms in sewage. Coliform organism is used as an indicator organism of sewage pollution, therefore, the presence of coliform organism indicates that pathogenic agents can exist.

Plant nutrients

Industrial and sanitary wastewater contains nitrogen and phosphorus compounds which are essential nutrients for the growth of plants with carbon, so when these materials are discharged into the aquatic environment, they may cause the growth of unwanted aquatic life. This phenomenon is called enrichment or eutrification. Also, if this type of sewage is discharged in large quantities on the ground, it may cause groundwater pollution.

Primary pollutants

They are organic and inorganic compounds that are identified based on known or suspected effects of carcinogenicity, chromosomal mutation, disability, or extreme toxicity. Many of these compounds are found in wastewater, which must be removed by wastewater treatment.

Resistant organic materials

These organic substances often resist conventional wastewater treatment methods so their treatment is complicated. The most common of them are cleaners, petroleum and petrochemicals, phenols and pesticides.

Resistant organic materials

These organic substances often resist conventional wastewater treatment methods so their treatment is complicated. The most common of them are cleaners, petroleum and petrochemicals, phenols and pesticides.

Heavy metals

Heavy metals include mercury, lead, arsenic, silver, copper, iron, cadmium, chromium, nickel, etc., the presence of each of which causes toxicity in water. Heavy metals are often introduced into wastewater as a result of commercial and industrial activities, and their separation is necessary if the wastewater is to be reused.

Dissolved inorganic substances

Inorganic components such as calcium, sodium, and sulfate are added to urban water resources as a result of water consumption, and if we want to reuse the wastewater, these materials must be separated. For example, sodium increases the corrosiveness of water and is toxic to plants in high concentrations.

Conclusion

In this article, the types of important pollutants in industrial and sanitary wastewater treatment were investigated and the reasons for the importance of removing each of them were explained. According to the goals of wastewater treatment, the removal of each of these pollutants requires the correct selection of the treatment method so that the wastewater treatment plant system has the highest efficiency in removing pollutants.

Sources

• https://www.britannica.com/technology/wastewater-treatment/Sources-of-water-pollution
• MAJOR CONTAMINANTS IN INDUSTRIAL AND DOMESTIC WASTEWATER , Olga V. Vysokomornayaa, E. Yu. Kurilenko, Anastasia A. Shcherbinina , National Research Tomsk Polytechnic University, 634050 Tomsk, Russia
• ابریشم چی، احمد، افشار. عباس و جمشید، بهشید: مهندسی فاضلاب، جلد اول، مرکز نشر دانشگاهی( با همکاری شرکت مهندسان مشاور طرح و تحقیقات آب و فاضلاب) اصفهان، چاپ اول، 1374.