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Coliform Bacteria in Water and Sewage. How to Remove It?

Safe drinking water is essential for maintaining good health. Coliform bacteria serve as indicators of water quality, helping to identify potential risks associated with fecal contamination. Understanding the significance of coliform bacteria and their role in sewage treatment is crucial in ensuring the safety of water resources.

How to remove coliform bacteria from my water? Read more in this article written by our experts.

How to remove coliform bacteria in water?
How to remove coliform bacteria in water?



Importance of Coliform Bacteria Testing in Water

It is not practical to test water for every disease-causing microorganism, but it is easy to test for a group of indicator bacteria called total coliform bacteria. These bacteria are good indicators of sanitary protection of the well and water system because they are everywhere on the surface of the ground, but do not usually occur past a few feet into the soil. If they show up in a water test, they can indicate that surface contamination has gotten into the water and that disease-causing microorganisms may be present. Just as disinfection kills most disease-causing microorganisms, it also kills coliform bacteria.

Testing for coliform bacteria in water is vital for assessing its safety. By monitoring the levels of coliform bacteria, water quality experts can identify potential sources of contamination and take appropriate measures to safeguard public health. The presence of coliform bacteria is an indicator that harmful pathogens might be present, requiring further investigation and treatment.

Sources of Coliform Bacteria in Water

Coliform bacteria can enter water sources through various means. Some common sources include untreated sewage, animal waste, agricultural runoff, and faulty septic systems. Contaminated water bodies, such as rivers or lakes, can also introduce coliform bacteria into drinking water supplies if not properly treated.

Health Risks Associated with Coliform Bacteria

While most coliform bacteria do not cause disease, their presence suggests there may be disease-causing microorganisms in your water.

Ingesting water contaminated with these microorganisms can cause diarrheas, dysenteries, salmonellosis, hepatitis, and giardiasis. Symptoms include diarrhea, vomiting, cramps, nausea, headaches, fever, fatigue, and even death sometimes. Infants, children, elderly people, and people with weakened immune systems are more likely to get sick or die from disease-causing microorganisms in drinking water.

Coliform Bacteria in Sewage Treatment

Sewage treatment plays a crucial role in removing pollutants and harmful microorganisms from wastewater. Coliform bacteria are commonly found in sewage due to their prevalence in the human gut. Understanding the behavior of coliform bacteria in the sewage treatment process is essential for effective treatment and the production of clean water.

Role of Coliform Bacteria in Sewage Treatment Processes

Coliform bacteria serve as indicators of the efficiency of sewage treatment processes. Monitoring the levels of coliform bacteria at different stages allows operators to assess the effectiveness of treatment methods. By measuring the reduction in coliform bacteria, treatment plants can ensure that wastewater is adequately treated before being discharged into the environment.

Monitoring and Control of Coliform Bacteria in Sewage Treatment Plants

Sewage treatment plants implement rigorous monitoring and control measures to manage coliform bacteria levels. Regular sampling and testing are conducted to assess the treatment plant's performance and compliance with regulatory standards. If elevated levels of coliform bacteria are detected, adjustments to the treatment process can be made to improve efficiency and protect public health.

Ensuring Safe Drinking Water

To ensure safe drinking water, it is crucial to implement multiple barriers against coliform bacteria contamination. This includes source water protection, effective treatment processes, and routine testing. Public water systems should adhere to strict guidelines and regulations to provide consumers with clean and safe drinking water.

Regulatory Standards for Coliform Bacteria in Water

Regulatory bodies, such as the Environmental Protection Agency (EPA), have established standards for coliform bacteria in water. These standards dictate the maximum allowable levels of coliform bacteria in drinking water supplies. Public water systems must comply with these standards to protect public health.

Water Treatment Technologies for Coliform Bacteria Removal

Water treatment technologies play a crucial role in removing coliform bacteria from drinking water supplies. Processes such as disinfection, filtration, and chlorination are commonly used to eliminate or reduce the presence of coliform bacteria.

Advanced technologies, including ultraviolet (UV) disinfection and membrane filtration, are also employed for enhanced treatment efficacy.

You can get in touch with our team for a free consultation about these technologies.

UV Light Treatment Equipment for Coliform Bacterial Removal from Water
UV Light Treatment Equipment for Coliform Bacterial Removal from Water

Preventive Measures to Reduce Coliform Bacteria Contamination

Preventing coliform bacteria contamination requires a multi-faceted approach. Implementing proper sanitation practices, maintaining septic systems, and practicing responsible agriculture are essential. Additionally, public education campaigns can raise awareness about the importance of water hygiene and encourage responsible water usage.

Well Water Contamination

Typically, most of groundwater is free of disease-causing microorganisms. The upper layers of soil and rock filter the water as it soaks into the ground. You can do the following to help maintain this natural protection:

  • Make sure your well is located and constructed properly. Work with a licensed well contractor to do this.

  • Inspect your well regularly and repair any damage. Things to look for are:

    • Damage: Any cracks or holes in well casing, corrosion, loose wires, or soil settling?

    • Well cap: Is it securely attached to the well casing? Is it broken or missing?

    • Connections: Are the electrical conduit and other connections watertight?

    • Mark your well with flags or posts to avoid hitting it with vehicles.

    • Keep the well area clear of debris.

    • Maintain minimum isolation distances from contamination sources, such as fertilizers, pesticides, septic systems, and feedlots

    • Do not tie animals to your well.

Test for Coliform Bacteria every year

Water quality can change. Minnesota Department of Health (MDH) recommends you test every year for coliform bacteria, even if you have not noticed any changes in your water quality. MDH also recommends you test for coliform bacteria any time your well or water system is worked on or the water changes in taste, smell, or look.

MDH recommends you use an accredited laboratory to test your water. Contact an accredited laboratory to get sample containers and instructions, or ask your county environmental or public health services if they provide well testing services.

What to do if your water tests positive for Coliform Bacteria

If your water or sewage test positive for coliform bacteria:

1. Use boiled or bottled water or water from a safe alternative source for cooking and drinking until you address the issue. Distillation with vacuum evaporators for industrial applications.

If nitrate or arsenic were also detected in your well water, boiling your water may not be the safest option. Boiling water that has these contaminants can increase their concentration and cause health problems.

2. Disinfect your well with a chlorine solution. Contact a licensed well contractor to disinfect your well, or use the instructions on the Well Disinfection webpage.

3. Test your well water again after disinfection to confirm there are no coliform bacteria.

4. You can use the water again, without boiling, once the well has been disinfected and the water no longer tests positive for coliform bacteria.

What to Do if All Disinfection Attempts Fail

Sometimes disinfection alone will not take care of the issue. In these cases, work with a licensed well contractor to figure out what to do. You may have to take special measures, such as bailing out debris from the well or constructing a new well. Possible causes are:

  • Small animals or debris got into the well.

  • Openings or cracks developed in the upper part of the well casing.

  • Soil and rock may not be adequately filtering the water, and surface bacteria may be traveling deeper than usual.



1. Are all coliform bacteria harmful?

Not all coliform bacteria are harmful. However, their presence in water suggests a potential risk of contamination by other harmful microorganisms.

2. How do coliform bacteria enter water sources?

Coliform bacteria can enter water sources through various means, including untreated sewage, animal waste, agricultural runoff, and faulty septic systems.

3. What are the health risks associated with coliform bacteria?

Ingesting water contaminated with coliform bacteria can lead to gastrointestinal illnesses, such as diarrhea, cramps, and nausea, as it may indicate the presence of other pathogenic microorganisms.

4. How are coliform bacteria monitored in sewage treatment plants?

Coliform bacteria levels in sewage treatment plants are regularly monitored through sampling andtesting. This helps assess the efficiency of the treatment processes and ensures compliance with regulatory standards.

5. What can individuals do to prevent coliform bacteria contamination?

Individuals can take preventive measures such as practicing good hygiene, maintaining septic systems, and adopting responsible agricultural practices. These actions contribute to reducing the risk of coliform bacteria contamination in water sources.

6. How can I remove coliform bacteria from water?

UV light filters are effective in remove such coliform bacteria from water. Get in touch with our team to find the best equipment configuration for your water.


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