Due to the increasing use of drugs in communities, one of the most important problems in the world is the presence of these substances, especially antibiotics, in the environment. The presence of these substances can have devastating effects on the environment and human health. In recent years, these drugs have been continuously discharged into the environment without any restrictions; Although their entry into aquatic environments may be low, their continuous navigation due to their cumulative effect can be considered a major threat to aquatic ecosystems and their microorganisms. The presence of these antibiotics in the environment, including the aqueous environment, can cause various reactions from simple allergies to in some cases direct toxicity; In addition, the presence of these drugs in the environment leads to the resistance of organisms to antibiotics, which seriously threaten the functioning of the ecosystem and human health.
In general, the effects of the presence of antibiotics can be divided into 4 categories, which are:
Aquatic environments, including sewage, as the main recipient of intestinal bacteria, are a favorite place for many bacteria to become resistant to various types of antibiotics. Due to the fact that a few antibiotics are biodegradable, most of them go through biological wastewater treatment processes and enter the environment without decomposition and metabolism.
2. Surface water
Substances that have not been removed in the wastewater treatment plant or have been removed in small amounts will eventually reach surface waters, which may affect various organisms. Among the organisms that are sensitive to antibiotics in surface water, we can mention green-blue algae.
3. Sediments and soil
Soil is one of the ecosystems that have large amounts of antibiotics due to receiving animal fertilizers. Antibiotics affect soil-dwelling microorganisms. Antibiotics may affect the quantity and quality of microorganisms and reduce the number of soil microorganisms.
4. Impact on humans
Antibiotics and antibiotic-resistant genes have been observed in purified water and the distribution system. The presence of antibiotic-resistant genes poses health risks to humans through the transfer of bacteria-resistant genes. Studies have shown that some antibiotic-resistant microorganisms can survive chlorination operations and eventually enter the drinking water system. Although the concentration of antibiotics in the surface water is very low, many people are concerned about the presence of drugs in drinking water because the drugs are designed to act on certain proteins. Among the effects of antibiotics can be allergic reactions. One of the effects of using tetracycline on children is damage to the teeth. Humans are also exposed to these substances by consuming plants and vegetables such as carrot root, lettuce leaves, and corn, which have absorbed antibiotics from water or sediments.
In engineering, there are several ways to remove these materials. Given the destructive effects of the presence of these substances in the environment, the importance of maximum elimination of drugs, especially antibiotics, is obvious.
Some methods of removing antibiotics are:
- Advanced oxidation
- Use of biosorbents
- Biological degradation
- Electric coagulation
- Pre-treatment with a continuous batch reactor
- Secondary sludge treatment
Author: Maryam Pasandidehnia, Study of Separation of Antibiotics from Wastewater by Adsorption Method, 2021