Sewage-contaminated water contains many microorganisms, from Bacteria to viruses, fungi, and Protozoa. These microorganisms can cause a broad variety of diseases such as cholera, typhoid fever, and dysentery.

The role of microorganisms in water pollution is that they decompose organic matter in the sewage and consume oxygen from the water. This process depletes the dissolved oxygen content of the water, which can lower the quality of lakes and water streams where high levels of oxygen are required for the aquatic life.

Escherichia coli /coliforms are coomonly used as an indicator of fecal contamination. Too the extent that "sewage" includes fecal waste, these are useful. Some applications/proposals offer Candida albicans, phages, staph aureus fecal streptococci

Dr Phil Geis thank you for your contribution to the discussion

Pathogens typically found in sewage include Salmonella, Shigella, E. coli, Streptococcus, Pseudomonas aeroginosa, mycobacterium and Giardia Lamblia. Bacteria may cause diarrhea, fever, cramps, and sometimes vomiting, headache, weakness, or loss of appetite. Some bacteria and diseases carried by sewage and wastewater are E. coli, shigellosis, typhoid fever, salmonella, and cholera. Fungi such as Aspergillus and other fungi often grow in compost. Most common anaerobic forms belong to Actinomyces, Bifidobacterium, Clostridium, Propionibacterium and Peptostreptococcus genera. Facultative Bacteria: In sewage treatment, facultative microorganisms are bacteria that can switch between aerobic and anaerobic states depending on their surroundings. The presence of coliform bacteria, specifically E. coli in drinking water suggests the water may contain pathogens that can cause diarrhea, vomiting, cramps, nausea, headaches, fever, fatigue, and even death sometimes. These microbes consume the organic mass of the waste water and utilize the nutrients from sewage for their growth, ultimately enhancing the cleaning action of waste water. The treatment can restore water quality and increases the self-cleansing capacity of the water body. Microbes digest organic waste by stealing its oxygen, altering the chemical makeup of the material into a less environmentally damaging matter. EM bacteria has been widely applied in wastewater treatment decomposing pollutants in the environment by facilitating nitrification, denitrification, ammonification, and other processes, then improving water and soil quality without damages to the environment.

Tho' some variants in foods are, E. coli is not a pathogen - it is normal flora. In water context, it is an indicator orgnanism.

Pseudomonas aerugnisa is also an environmental organism - common in all waters, polluted or not.

Dr Phil Geis thank you for your contribution to the discussion

Sewage-contaminated water contains many microorganisms originating from human waste and the environment. These microorganisms can range from harmless, naturally occurring species to harmful pathogens. Here are some of the microorganisms commonly found in sewage-contaminated water:

Role of Microorganisms in Water Pollution:

Dr Tanzir Islam Britto thank you for your contribution to the discussion

The common sewage bacteria include species of coliforms, streptococci, clostridia, lactobacilli, micrococci, Proteus and Pseudomonas. Most of these bacteria re causative agents of fatal diseases like gastro, typhoid, cholera and food poisoning in humans.Bacteria, specifically, E. coli or fecal Streptococci are well-known indicators of sewage pollution in drinking and bathing water. Of the many infectious microorganisms found in the environment, bacteria (such as Shigella, Escherichia coli, Vibrio, and Salmonella), viruses (such as Norwalk virus and rotaviruses), and protozoans (such as Entamoeba, Giardia, and Cryptosporidium) may be found in water. The two categories of naturally occurring microbes present in sewage are bacteria and fungi. The bacteria along with the fungal filaments form flocs which are utilized during the secondary treatment of sewage. The primary effluent after separation of the grit and debris is taken to the secondary treatment. Bacteria may cause diarrhea, fever, cramps, and sometimes vomiting, headache, weakness, or loss of appetite. Some bacteria and diseases carried by sewage and wastewater are E. coli, shigellosis, typhoid fever, salmonella, and cholera.Wastewater contains nitrogen and phosphorus from human waste, food and certain soaps and detergents. Once the water is cleaned to standards set and monitored by state and federal officials, it is typically released into a local water body, where it can become a source of nitrogen and phosphorus pollution. The microbes simply eat up contaminants such as oil and organic matter, convert them and then let off carbon dioxide and water. The process uses naturally occurring bacteria, fungi or plants to degrade substances that are hazardous to human health or the environment. Bacteria, specifically, E. coli or fecal Streptococci are well-known indicators of sewage pollution in drinking and bathing water. In sanitary microbiology, some bacterial groups of organisms have been widely used as an indicator of water pollution. Biological wastewater treatments employ microorganisms to remove organic matter from water. Organic matter or pollutants stem from number of sources, such as drainage systems or acid rain. The use of microorganisms in wastewater treatment results in the following: FOG (Fats, Oil and Grease) removal. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci.

Please see: https://www.nature.com/articles/s41598-019-46015-z

As 16S, this only reports bacteria signal.

Dr Phil Geis thank you for your contribution to the discussion

The common sewage bacteria include species of coliforms, streptococci, clostridia, lactobacilli, micrococci, Proteus and Pseudomonas. Most of these bacteria re causative agents of fatal diseases like gastro, typhoid, cholera and food poisoning in humans.These microbes consume the organic mass of the waste water and utilize the nutrients from sewage for their growth, ultimately enhancing the cleaning action of waste water. The treatment can restore water quality and increases the self-cleansing capacity of the water body. The liquid sewage is then transferred to secondary treatment which focuses on removing the dissolved biological compound by the use of micro-organisms. The micro-organisms usually use aerobic metabolism to degrade the biological matter in the liquid sludge. These anaerobic bacteria digest the bacteria and fungi in sludge. Thus, use of microbes in sewage treatment helps to remove organic matter from waste water before it is discharged in water bodies like rivers. Coliform bacteria, Escherichia coli and coliphages are normally used as indicators of water quality. Inside the septic tank itself, where less air is available, anaerobic bacteria are the main type of bacteria that break down the effluent. These bacteria can decompose solid waste by eating it. Single-celled creatures known as protozoa play a role in your wastewater treatment as well.