How Many Pathogens Are Removed By Septic Tank?

Is your septic system properly treating your wastewater?

  • Many homeowners rely on septic systems for safe and effective treatment of their wastewater. Household wastewater is treated by a septic system before it filters into the soil. Recycled water from a septic system can help replenish groundwater supplies; however, if the system is not working properly, it can contaminate nearby waterbodies.

What is the percentage of purification of septic tank effluent?

A septic tank will remove 30 to 50% of BOD (Biological Oxygen Demand), 40 to 60% of TSS (Total Suspended Solids) (UNEP 2004) and result in an abatement of 1 log units E.

How are pathogens removed from sewage?

In most western wastewater treatment plants, raw sewage is treated with combined mechanical, biological, and chemical processes such as screening, flocculation, sedimentation, and filtration. Gross pollutants and most organic and inorganic solids are removed during these steps.

What do septic tanks remove?

The septic tank digests organic matter and separates floatable matter (e.g., oils and grease) and solids from the wastewater. Some alternative systems are designed to evaporate wastewater or disinfect it before it is discharged to the soil.

What percentage of the solids are removed in a septic tank?

Up to 50 percent of solids retained in the tank decompose while the remainder accumulate as sludge at the tank bottom and must be removed periodically by pumping the tank. Three main types of septic tanks are used for wastewater treatment: Concrete. Fiberglass.

What are the three 3 bacteria that separates by septic tank?

Septic tanks work by allowing waste to separate into three layers: solids, effluent and scum (see illustration above). The solids settle to the bottom, where microorganisms decompose them. The scum, composed of waste that’s lighter than water, floats on top.

What is the pH of a septic tank?

But for bacteria to thrive in the septic tank, a pH of 6.5-7.5 is needed. It is therefore vital to maintain the wastewater in the septic tank within this range of pH in order to keep the microorganisms alive and well. When the septic tank pH gets higher than the recommended range, microbial activity will be inhibited.

What is the removal of pathogens?

Principal removal processes are those most frequently used to remove the majority of the microbes in the water being treated. These processes are sedimentation, flotation, and high-rate granular media filtration. They are often used in conjunction with coagulation and flocculation.

How are pathogens removed from water?

Boiling can be used as a pathogen reduction method that should kill all pathogens. Water should be brought to a rolling boil for 1 minute. At altitudes greater than 6,562 feet (greater than 2000 meters), you should boil water for 3 minutes.

What is the best way to remove or destroy the pathogen?

” Dilution of room air with clean disinfected air is one of the easiest and best-known methods to remove pathogens and to decrease the risk of infections in rooms,” wrote Bolashikov and Melikov in 2008, and it’s still true today.

What happens to poop in a septic tank?

The inlet pipe collects the water waste in the septic tank, long enough that the solid and liquid waste is separated from each other. Inside the tank bacteria from the wastewater breaks down the solid waste. These bacteria decompose the solid waste rapidly allowing the liquids to separate and drain away more easily.

How long do septic tanks last?

A septic system’s lifespan should be anywhere from 15 to 40 years. How long the system lasts depends on a number of factors, including construction material, soil acidity, water table, maintenance practices, and several others.

What are the 3 types of septic systems?

Types of Septic Systems

  • Septic Tank.
  • Conventional System.
  • Chamber System.
  • Drip Distribution System.
  • Aerobic Treatment Unit.
  • Mound Systems.
  • Recirculating Sand Filter System.
  • Evapotranspiration System.

How do you remove solids from a septic tank?

One is to inject air into the tank to try and mix the contents and break down the solids. The more common method is to use a mechanical mixer that acts somewhat like a baking mixer where the contents are mixed until they form a slurry that can be withdrawn by the vacuum pump.

How much solids should be in a septic tank?

Both the regulatory and pumping industry recommend that the sludge and scum layer in a septic tank should never be permitted to fill more than about 30% of the septic tank’s volume.

How do you get solids out of a septic tank?

Here are a few things you can do to help you break down the solid waste in your septic tank:

  1. Active Yeast. Add ¼ to ½ cup of active dry yeast to your toilet bowl and flush it down your toilet.
  2. Rotten Tomatoes.
  3. Hydrogen Peroxide.
  4. Inorganic Acids.
  5. Chemicals.
  6. Pumping.

Septic Systems and Surface Water

1. Bathrooms and Kitchens Wastewater from toilets, sinks, showers, and other appliances contains harmful bacteria, viruses, and nutrients that could contaminate nearby surface water sources. You can help reduce the amount of nutrients in your wastewater by limiting use of the garbage disposal and using phosphate-free detergents. Avoid flushing other chemicals or medications down the drain or toilet since they could also contaminate surface water sources.
2. Septic Tank Wastewater generated in your home exits through a drainage pipe and into a septic tank. The septic tank is a buried, water-tight container that holds wastewater for separation and treatment. The solids settle to the bottom (sludge) and fats, oil and grease float to the top (scum). Microorganisms act to break down the sludge and destroy some of the contaminants in the wastewater. Your septic tank should be serviced and pumped on a regular basis to make sure it’s working properly. Learn more about how your septic system works.
3. Drainfield The drainfield is a shallow, covered trench made in the soil in your yard. Partially treated wastewater from the septic tank flows out through the drainfield, filters down through the soil and enters the groundwater. If the drainfield is overloaded with too much liquid or clogged with solids, it will flood and cause sewage to surface in your yard or back up into your home. Learn more about maintaining your drainfield.
4. Wastewater Treatment in Soil Filtering wastewater through the soil removes most bacteria and viruses (also known as pathogens) and some nutrients. While soil can treat many contaminants, it cannot remove all of them (e.g., medicines, cleaning products, other potentially harmful chemicals). If untreated wastewater surfaces in the yard, wastewater may contaminate the streams, lakes, or coastal waters near your home. Avoid putting chemicals or medications down the drain or toilet since they could end up in surface waters too. Learn more about sources of and solutions to nutrient pollution.Learn more about preventing eutrophication.
5. Water Table The water table is where you first hit water if you dig a hole into the ground.
6. Groundwater The water below the water table is called groundwater. Groundwater flowing underneath a drainfield captures any remaining contaminants released from the septic system. A stream, lake, or coastal water is at greater risk of becoming contaminated if it is in the path of groundwater flow beneath the septic system. Learn more about getting up to speed with protecting groundwater.
7. Nutrients in Surface Water (Nitrogen, Phosphorus) When there are too many nutrients in surface water, they act as a fertilizer for fast-growing bacteria and algae. This rapid growth can cause algal blooms that can reduce water quality, kill aquatic animals and plants, and form toxins in the water. This process is called eutrophication. Harmful algal blooms (HABs) in lakes and streams can be toxic to humans and animals.Phosphorus: Depending on your soil type, phosphorus from wastewater can be absorbed and retained in the soil. Unabsorbed phosphorus can travel in groundwater toward a waterbody and become a source of contamination. Freshwater is more vulnerable to phosphorus pollution.Nitrogen: Some nitrogen may be removed as wastewater flows through the septic system and soil. But the remaining nitrogen can enter the underlying groundwater and flow towards a surface water body. If there are many septic systems in a small area, the nitrogen flowing through groundwater could overload a waterbody, causing eutrophication. Saltwater is more vulnerable to nitrogen pollution. Learn more about harmful algal blooms and cyanobacteria.
8. Setback Distance Most states or local governments require a specific horizontal distance (or setback) between a septic system and surface water bodies. If the soil where you live is sandy, or porous, you may want to place your septic system farther away than the minimum required distance. Contamination is less likely the farther away your septic system is from a body of water. Consult your local health department about required setback distances in your area.
9. Streams, Lakes and Coastal Waters Groundwater and surface water runoff flows into streams, lakes, and coastal waters. If this water contains contaminants, they can make their way into surface waters, causing eutrophication (see7). It’s important to keep surface waters healthy to use for recreation, fishing, and as a drinking water source. Learn more about the environmental problem of nutrient pollution.Learn more about the effects of nutrient pollution.

Pathogens & Your Septic System: Is Your Groundwater Safe?

It is estimated that more than a million Ohio households rely on septic systems to handle their waste water, according to the Ohio Department of Health. According to the Office of Disease Control and Prevention, 31 percent of them were failing in some way in 2015. Many homeowners are still unsure about whether bacteria are present in their septic system and how they may determine whether or not their groundwater is safe to drink, despite the fact that new regulations to further protect Ohioans from septic failure have been in existence since 2015.

Identify the pathogens that might be present in your septic system.

  • If the residents of the residence are suffering from illnesses that are transmitted by human waste, it is possible that germs will be present in the septic system.
  • Bacterial Pathogens That Could Be Found in Septic Systems In a septic tank, there are three types of bacteria that are always present in some form or another: aerobic bacteria, anaerobic bacteria, and fecal coliforms.
  • Anaerobic bacteria are smaller and less effective in breaking down solids than their aerobic counterparts, but they do not require oxygen to thrive and are more resistant to environmental changes.
  • They are beneficial to digestion and are not known to be disease vectors.
  • It is possible that pathogenic bacteria, such as those that cause typhoid fever, salmonella, and cholera, are present in a test sample of water if these bacteria are discovered.
  • The only viruses present in a septic tank are those that were flushed into it and survived.
  • However, because to the acidic pH of wastewater, it is extremely difficult for most viruses to survive for an extended period of time in a septic tank.

A number of researchers have looked at whether COVID-19 may be transferred through human feces because of how extremely contagious it is.

As with other viruses found in wastewater, the Environmental Protection Agency thinks that properly maintained septic systems will destroy COVID-19 as effectively as they do other viruses found in wastewater.

Upon leaving your house, wastewater travels to the septic tank, where it is deposited at the bottom and forms sludge, while grease and oil float to the top and form a layer of scum.

The greywater that collects between these two levels is referred to as effluent, and it flows out of the tank and onto a secondary treatment system, which is often a drainage field.

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Eventually, after passing through the drainfield, effluent reaches the soil, where it is cleaned naturally of any pathogens that may have survived the drainfield’s filtering process.

Pathogens and Groundwater Contamination: What You Should Know In the event that the septic system fails, or if the system is improperly installed, pathogens from the septic system may pollute groundwater.

This occurs as a result of excessive usage or the flushing of “no flush” objects into the system.

It is possible for a drainage field to get fully blocked when particles flow into it, preventing wastewater from flowing down through the secondary treatment system and being cleaned of toxins and pathogens.

In the event of a catastrophic failure, possibly polluted wastewater is permitted to pool on the surface of the ground above the drainage field.

When your septic system is properly maintained, you may avoid this sort of groundwater pollution from occurring.

It is also important to conserve water whenever possible and to be extremely cautious to prevent flushing the incorrect things into your septic system as part of proper maintenance.

Septic tank and drainfield installation requirements specify the location of the septic tank and drainfield in respect to any source of drinking water or neighboring streams.

Additionally, if the drainfield is built too close to a nearby stream, the effluent may be able to reach the stream before all toxins and pathogens have been eliminated from the system.

This will guarantee that the water in your house is safe to drink.

Our company has been delivering outstanding service to our community for the past 52 years, and we are delighted to be recognized as the biggest septic service provider in Northeast Ohio.

Articles that are related Environmental Issues Associated with a Failing Septic System Preparing for the Pumping of Your Septic Tank Taking Good Care of and Feeding Your Septic System Symptoms of a Failing Septic System

Out of sight, still a blight

Marcelo Fernandes, who grew up around Miami’s Biscayne Bay, has always had a favorite snorkeling spot: a 50-by-100-foot region where he could swim over coral reefs as recently as 2015, where he could swim above coral reefs However, he was unable to locate it a few years ago. He reasoned that he must have misplaced the coordinates. Then it dawned on him: he had really discovered his location, but the corals had perished. Fernandes lives in a verdant community named Bay Homes Park in south Coconut Grove, where tropical plants and flowers bloom in abundance along the area’s winding lanes.

  • In the last four years, at least six of his neighbors have had to repair or replace septic tanks that were damaged in some way.
  • That equates to approximately 13 percent of all septic tanks in the United States, which are below-ground receptacles for disposing of a home’s sewage.
  • Leaking tanks, on the other hand, spread pollutants in a state whose rivers are bursting with water.
  • The threats to individuals posed by old, leaky septic systems are less well-known, yet still exist.
  • According to Mary Lusk, a University of Florida professor of soil and water sciences, Florida’s weak soils have a lower capability for treating pathogens than soils in other regions of the country.
  • “If (a virus) can survive in the circumstances of a septic tank and make its way into water, it is possible that it may be a vehicle for the transmission of a disease,” Lusk said.
  • However, it is still uncertain whether a virus such as COVID-19 — which scientists have discovered has the ability to render itself dormant — might survive such circumstances and make its way into groundwater.

According to the Centers for Disease Control and Prevention, COVID-19 has been discovered in untreated wastewater, and the danger of transmission through adequately maintained sewage systems is considered to be minimal.

Septic tank numbers rising

The unknown is how well septic tanks are maintained — and this is why septic tanks have caused such widespread ecological devastation. “From the standpoint of the property owners, ‘working’ means that the toilet flushes,” explained Thomas Ruppert, a coastal planning specialist with the Florida Sea Grant. According to him, this is frequently not the case. A septic tank that is underwater, or one that is less than two feet above the water table, is considered to be broken. Whenever gravity is unable to transport the separated liquid, known as effluent, to the drain field below, nutrients and pathogens can enter streams and groundwater.

“It’s a difficult sale to make to homeowners, and that’s understandable,” Lusk said.

In addition, people are obliged to pay a firm to “pump” their system every three to five years in order to clear out the sediments that have accumulated.

According to William Lester, a UF/IFAS horticulture agent in Hernando County who is a member of the state’s “After the Flush” instructional program for homeowners and professionals, “I know folks who proudly claim, ‘I haven’t had my system pumped out in 20 years.'” “Yeah, that’s not a really good idea, is it?” The presence of disease-causing microbes in outdated or poorly maintained tanks might constitute a threat to human health.

  • Florida’s environmental authorities, on the other hand, have no way of knowing where every septic tank in the state is located, let alone how many are contaminated.
  • On the map of known and probable septic tanks, it can be seen that central sewer – which is sewage that is piped from a residence to a local treatment facility – is concentrated in urban areas.
  • Septic tank installations have been down in Florida for several years, but according to a recent research by WUFT News, their numbers are on the rise once more.
  • In the years before to 2008, the numbers were far higher, ranging from 21,000 to as high as 72,000 in certain years.
  • A grant program to encourage more households in nine springs-centered counties to upgrade to nitrogen-reducing systems was started by the Florida Department of Environmental Protection (DEP) following the passage of the Florida Springs and Aquifer Protection Act in 2016.

DEP subsidies provide up to $10,000 in compensation to licensed installers who assist homeowners in upgrading to safer tanks. According to the DEP, the agency has financed slightly more than 1,000 renovations since 2018, at a cost of $10 million total.

History of neglect

When septic tanks were still in use, blue-green algal blooms were widespread in the canals of the Florida Keys. Brian LaPointe, a resident and algal bloom researcher, said that the canals were considerably healthier within months following the city’s transition to centralized sewage. Throughout the twentieth century, septic tanks were mostly absent from Florida’s policymaking and legislative discussions. However, that has changed recently. Environments in the fragile Florida Keys were among the first to suffer as a result of the neglect.

  • Coral reefs have suffered a decrease.
  • Owners of homes on Big Pine Key, according to LaPointe, who resides on the island, were responsible for $4,500 of the costs associated with abandoning their tanks for the nearly $1 billion project.
  • A conventional septic system eliminates around 30% of the waste.
  • According to Department of Health and Human Services data, 107,000 and 50,000 tanks are in use in Miami-Dade and Broward counties, respectively.
  • Flooding, which is exacerbated by sea level rise and increased severe rains as a result of climate change, is also a significant cause of tank breaches and pollution.
  • This type of nutrient contamination, according to Silverstein, is a key cause to toxic algal blooms and seagrass reductions that have reached 90 percent in Biscayne Bay.

In locations with more permeable soil, the Environmental Protection Agency suggests, but does not compel, the use of “alternative solutions.” According to Silverstein, the cost of moving to sewer systems, such as in Monroe County, or depending on homeowners to update their own septic systems, is the primary impediment to progress.

According to her, “the projects frustrate locals because they have to rip up roads and then they have to put it back together, and people are like, what was the point of six months of traffic for?” Due to the fact that everything is underground, they don’t notice a difference.

Slow-moving solutions

During the 2010 legislative session, Florida lawmakers approved a septic tank bill with actual fangs, mandating that tanks be inspected every five years to verify that they are operating correctly. However, the statute was overturned two years later by then-Governor Rick Scott as a result of widespread public opposition. As part of the 2016 springs bill, objectives known as Basin Management Action Plans (BMAPs) were established to reduce nitrogen levels in areas that were most vulnerable to groundwater pollution, all of which were located in North Florida.

  1. Regardless, 58 counties were left out of the law, including large expanses of coastal areas where septic tanks have been shown to be harmful to the environment and dangerous to human health.
  2. The University of Florida soil science expert, Lusk, says that even if septic systems properly remove 99 percent of bacteria and protozoa, there is still the possibility that the remaining 1 percent will make its way into drinking-water wells.
  3. She anticipates that in the next years, there will be a greater emphasis on replacing aging and faulty tanks.
  4. Both have a price tag attached to them: up to $2,000 for installation and up to $280 per year in operation.
  5. In 2017, the tanks were eventually decommissioned.
  6. Long-term plans include the installation of porous pavement to reduce floods and the establishment of oyster beds in the Bay to filter pollutants.
  7. Bioreactor systems are an advanced step of tank treatment that complements ordinary tank treatment.
  8. According to Fernandes, the coronavirus epidemic has forced the postponement of community gatherings and development.
  9. This spring, the Legislature approved the Clean Waterways Act, which, among other things, would move septic tank regulation from the Department of Health and Human Services to the Department of Environmental Protection.
  10. In his statement, Groover of the sewage association stated that the move will allow the state to better focus on septic problems and assist more homes with upgrade expenditures.

They pointed out that, among other shortcomings, the Act does not go far enough in adopting recommendations from the state’s Blue Green Algae Task Force, such as “a septic system inspection and monitoring program” to identify and remove malfunctioning systems in order to “reduce nutrient pollution.and preserve human health,” among other recommendations.

Residents of Bay Homes Park are looking forward to the impending summer showers. According to Fernandes, “it’s not a rosy picture.” “Even if we start now, we’ll still lose a significant amount of money.”

Next:Part 4: People Power

Norweco provided the image used here.

Interested in Safety?

Receive safety articles, news, and videos delivered directly to your email! Now is the time to sign up. Safety+ Receive Notifications It is inevitable that wastewater will include fecal coliforms. These bacteria may be found in the intestines of all warm-blooded animals, including humans, and they are a source of infection. Despite the fact that they are necessary for digestion, they are also markers of the presence of infections. Pathogens such as Giardia, Cryptosporidia, Salmonella, Shigella, Vibrio cholerae, and other pathogens will only be present if persons who use the wastewater treatment system are infected with the pathogen.

Viruses and pathogens are abundant in wastewater, and they may be found almost anyplace and on anything that comes into touch with the wastewater.

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The highest concentrations of bacteria are found in the septic tank, and their numbers decrease as wastewater is treated as it travels down the drainage system.

  • The bacteria E. coli and other bacteria, protozoans such as Giardia and Cryptosporidia, and certain viruses are responsible for gastroenteritis (cramping stomach cramps, diarrhea, and vomiting). It is caused by the bacterium Vibrio cholerae and results in acute diarrhea and dehydration. Infection with the bacterium Leptospira causes leptospirosis (flu-like symptoms that are accompanied by a persistent and severe headache). Hepatosplenomegaly, renal failure, and blood poisoning are all possible consequences of leptospirosis. Hepatitis A is an infectious hepatitis characterized by jaundice and fever caused by the virus hepatitis A. It is known to cause liver inflammation. The hepatitis A virus (HAV) is characterized by jaundice, which is characterized by yellowing of the skin or whites of the eyes. Tiredness, stomach discomfort, nausea, and diarrhea are some of the other symptoms. Approximately 15% of those infected with HAV will experience protracted or recurrent symptoms over a period of six to nine months. A bacterial infection that causes Legionellosis (lung inflammation accompanied by fever, dry cough, and sore muscles and joints)
  • Infections of the skin and eyes

Pathogens may enter the body through four basic methods, which are described here. These are some examples:

  1. Ingestion via the mouth is caused by direct contact with the mouth when eating, drinking, and smoking as well as cleaning your face with infected hands or gloves. The most common route of infection is by ingestion. Skin – Contact with the skin caused by wastewater splashes. The presence of cuts, scrapes, and wounds increases the likelihood of infection. Disease-causing pathogens can enter your body through your eyes. Airborne germs delivered by dust, mist, or fumes enter the lungs and cause infection. Aerosols, including viruses (polioviruses, coxsackieviruses, echoviruses, rotaviruses, adenoviruses, Norwalk virus), bacteria, and other microorganisms have been shown to impair the immune system and have the potential to cause allergies in susceptible individuals (Leptospira, Salmonella spp., Shigella spp.,Campylobacter jejuni, Yersinia enterocolitica, Legionella pneumophila, Helicobacter pylori, Listeria monocytogenes, Mycobacterium xenopi). Another potential danger identified by the study was the presence of microbial allergens and endotoxins. According to the findings of the study, endotoxins, which are created by bacteria, can induce respiratory and intestinal inflammation, diarrhea, weariness, and nasal irritation among sewer workers.

There are several places that are polluted with microorganisms that are associated with septic systems. Inhalation of contaminated air in the proximity of wastewater might cause respiratory exposure. Dermal exposure is caused by objects such as tools, automobile door handles, radio knobs, and gear shifters. Oral pathogen intake can occur as a result of eating lunch on the job site, smoking cigarettes, chewing gum, and other activities.

How to protect yourself and your employees

Pathogens cannot be eradicated from wastewater since they are naturally occurring in the environment. When you practice proper personal hygiene and use personal protection equipment while on the job, your chances of catching an illness are reduced. The following are some recommended practices and other considerations to bear in mind:

  • Make sure you understand the dangers these microorganisms represent to your health, as well as the methods in which you might become infected. Keep a first-aid kit on hand at all times. All exposed wounds should be cleaned and disinfected before being covered with a sterile, waterproof dressing. Any injuries sustained on the job site should be reported to your supervisor as soon as possible. On the workplace, use waterless hand cleansers, antibacterial soaps, and antibacterial hand wipes to keep your hands healthy. It is not permissible to eat or drink at a wastewater treatment facility. Touching your nose, mouth, eyes, or ears with your hands is not recommended unless your hands have recently been cleaned. Hands should be thoroughly washed with soap and hot water before eating or smoking, as well as at regular intervals during the day and at the conclusion of your job. Assume that anything that comes into contact with wastewater is polluted. It is recommended that you wear a respirator if you are likely to be exposed to airborne infections, such as spray from a treatment device or a humid environment. It is suggested by the National Institute for Occupational Safety and Health that you use a N95 respirator. It is always crucial to ensure that your respirator is properly fitted. Check to see that the seal between the face and the mask is as tight as possible. The intake of tainted air would ensue if there was a leak. The growth of facial hair is avoided because it can interfere with the appropriate fit of a respirator. To ensure that respirators are correctly fitted, worn, and used, it is strongly recommended that a respiratory protection program be implemented.

Norweco provided the image used here.

  • Clean every portion of your body that has been exposed to wastewater or sludge as soon as possible
  • Maintain the length of your fingernails and clean them on a regular basis. While cleaning pumps or screens, or when handling wastewater, sludge, or grit, it’s a good idea to use waterproof gloves. Wearing heavy-duty gloves (preferably a double glove) and boots that are waterproof and puncture-resistant is recommended whenever feasible. If there is a danger that you will be splattered with wastewater, put on a surgical-type mask, goggles, face shield, or visor to protect your face. Whenever possible, use rubber boots or footwear that can be sanitized in the event that you come into contact with wastewater. Any broken equipment should be reported immediately for replacement or repair. Handle sharp objects with particular caution in order to avoid inadvertent accidents. Bleach solution should be used to clean any contaminated equipment and tools on the job site (1 tablespoon of bleach to 1 gallon of water). After being exposed to sunshine or dirt, bleach loses its potency
  • Thus, always have a new supply on hand. Before you leave work for the day, shower and change out of your working attire. Do not bring infected garments into your house for washing or dry cleaning. Separate your business clothing from your everyday clothes by storing them in two distinct lockers. If you have to wash your clothes at home, make sure to separate your work clothes from your family clothes. Work clothes should be washed in hot water with chlorine bleach. Discuss your profession with your health-care providers so that they are aware of any possible exposures you may be experiencing as a result of your job. Make sure your vaccinations are up to date, especially those for tetanus and diphtheria, before going out. It is extremely suggested that you get vaccinated against hepatitis A. If you have any flu-like symptoms, such as a fever or severe headache, or if you have any skin infections, you should see your doctor right once. If you experience chest symptoms that are consistent with asthma, get medical attention.

a little about the author: Sara Heger, Ph.D., is an engineer, researcher, and lecturer in the Onsite Sewage Treatment Program at the University of Minnesota’s Water Resources Center. She holds a bachelor’s degree in civil engineering and a master’s degree in environmental science. She has given presentations at several local and national training events on topics such as the design, installation, and administration of septic systems, as well as research in the related field. Her responsibilities include serving as the education chair for the Minnesota Onsite Wastewater Association and the National Onsite Wastewater Recycling Association, as well as serving on the National Science Foundation’s International Committee on Wastewater Treatment Systems.

Send an email to [email protected] if you have any concerns concerning septic system care and operation. Heger will respond as soon as possible.

The Role of Microbes in Your Septic System

Generally speaking, your septic system works in three steps to treat wastewater:

  1. The wastewater in your septic tank divides into three layers: scum, wastewater, and sludge
  2. The scum layer is the most visible. After that, the partially cleansed wastewater passes via a distribution box, which divides the water across drain field lines. Eventually, water will filter out through the perforated pipes and into the surrounding soil when it reaches the drain field lines.

Microbes, and specifically bacteria, play a significant role in the treatment of sewage, both in the septic tank and after the water reaches the land.

Microbes in the Septic Tank

During the separation process in the septic tank, wastewater is separated into three layers. Aerobic bacteria, which use oxygen in order to digest waste, are responsible for breaking down the top layer of scum. Bacteria in the sludge at the bottom of the septic tank use anaerobic digestion to break down the sludge, which does not require the presence of oxygen to occur. Solid trash can decompose into gases such as methane, hydrogen sulfide, and sulfur dioxide, accounting for up to half of all garbage generated.

Microbes in the Drain Field

After passing through the septic tank’s middle layer, the partially cleansed wastewater runs out into the drain field, where it seeps into the surrounding soil through perforated drain pipes. Drain field pipes are surrounded by a biomat, which is formed by anaerobic bacteria and other microorganisms in the soil around them. Biomat is a thick, tar-like bacterial slime coating that grows around the pipes. Biomat self-cleans and controls itself, accumulating or degrading in response to the amount of biomass carried by the wastewater and the number of bacteria required to metabolize one another when the available biomass levels fall below a certain threshold.

  • As the water passes through the biomat, it slows it down and begins to feed on the nutrients that are still present in the water.
  • Filtration Filtration occurs when wastewater passes via cracks, fissures, and pores in the soil around the drain field, allowing it to pass through the soil and biomat.
  • They gradually accumulate to the point where the system becomes clogged, lowering the flow rate of the water and restricting the mobility of the pathogens.
  • The majority of viruses that are trapped are collected by adsorption because their tiny size makes them less likely than other pathogens to be prevented by filtration.
  • During this period, the cleansed water dissipates through the surrounding soil, eventually returning to the water table of the area.

If you want to be sure that your septic tank has the correct concentration and type of bacteria, we recommend that you check out our BioMax septic tank treatment solutions, which are available online.

Determining the Effectiveness of On-site Septic Systems foe the Removal of Viruses

Return to the list of all publications George R. Heufelder and others are the authors. M.S. R.S. (Master of Science in Research and Statistics) Published: 2000


When the Commonwealth of Massachusetts revised its onsite wastewater treatment laws in 1995, it was in response to breakthroughs in the field of onsite wastewater treatment that the standards were significantly revised. While these modifications reflect many of the advancements in our understanding of the treatment of specific components, there was still much to be learned about the function of typical septic tank-leach fields in the treatment of pathogens, particularly viruses, at the time of their implementation.

  • less distance to groundwater or less available soil absorption system area).
  • Specifically, the goal of this study was to establish the efficacy of typical septic systems for the elimination of viruses and to compare this performance with that of chosen I/A systems.
  • The findings of our study have been presented in a variety of venues, including two journals, four national meetings, two regional meetings, and two annual meetings of the Massachusetts Environmental Health Association, among others.
  • Despite the fact that there is still much more study to be done, this grant has enabled us to serve as a significant resource to the DEP and health boards on matters relating to pathogens because of the funding.
  • Certain recommendations were prompted by a study of the literature, as well as concurrent research conducted as part of this project, which are presented in this report.
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  5. Collapse J.S.
  6. Sobsey are professors in the Department of Environmental Science and Engineering at the University of North Carolina School of Public Health.
  7. These systems are generally consisting of an influent pipe from the home into a septic tank, which serves as a settling chamber and anaerobic digester in addition to the other functions it performs.

When operating under ideal circumstances, the septic tank provides very minimal protection against microbial infections.

Absorption fields that are properly operating are efficient in eliminating microorganisms while posing minimal damage to human health.

It is estimated that almost half of the drinking water utilized in the United States comes from underground sources, and that polluted groundwater is responsible for roughly half of all water-borne epidemics (Craun, 1985).

This paper outlines the elements and situations that influence pathogen incidence and persistence in septic tank effluent, as well as pathogen eradication from it (STE).

EDWARD Viruses, bacteria, protozoa, and helminth eggs are the four types of pathogens that might possibly be found in human excreta.

Viruses have a high degree of host specificity.

Viruses behave like abiotic colloidal particles when they are not in contact with a host.

Bacteria are cellular entities that are prokaryotic in nature (1-6 mm in size).

The majority of these are the typical flora that lives in the stomach.

Protozoans are eukaryotic creatures that are unicellular in nature (1-15 mm in size).

Gastroenteritis and dysentery are two diseases that are caused by enteric protozoan infection.

They are multicellular eukaryotic parasites that infect other organisms.

Table 1 contains important representations of each of the four enteric pathogen categories, as well as other important representatives.

A greater percentage of protozoan cysts and helminth ova may be eliminated during this procedure than bacteria or viruses, owing to the bigger size of the cysts and helminth eggs.

In the septic tank, removal efficiency for all four pathogen groups range from 0-2 log 10(0-99 percent) for all four pathogen groups (Feachem, 1983).

As a total, the efficiency of removal for an ideally operating OSDS can approach 9 log 10 (or 99.9999999 percent) (Scandura, 1997). Table 1: Pathogens that are important in the human enteric system. Viruses/Groups Enteroviruses: Polios, echoes, etc.

  • Hepatitis A virus, Hepatitis E virus, Reoviruses, Rotaviruses, and Adenoviruses are all examples of viruses that can cause disease.

Norwalk, Snow Bacterium/Group, and other caliciviruses

  • Infections caused by Salmonella species
  • Campvlobacter species
  • Escherichia coli
  • Helicobacter pvlori
  • Aeromonas hydrophila and Yersinia enterocolitica
  • Yersinia enterocolitica Vibrio cholerae and other pathogens Bacteria such as Vibrio spp., Brucella, Leptospira, Mycobacteria spp. (non-tubercular), Shigellosis spp., and others
  • The cryptosporidium parvum, the Cyclospora caventensis, the Giardia lamblia, the Entamoeba histolvtica, the Balatidium coli, the Microsporidia, and the Toxoplasma gondii are all parasites.
  • In addition to the following species: Ancylostoma duodenale, Ascaris lumbridoides, Enterbius vermicularis, Necator americanus, Strongvloides stercoralis, Trichuris trichiura, and Necator americanus

FACTORS INTERFERING WITH THE REMOVEMENT OF PATHOGENS IN SAF The biological mat or clogging zone, which is located at the interface of the trench was and the soil, is where the most pathogens are removed from the STE system. The zone, which is just a few millimeters thick in a perfectly functioning OSDS, works as a filter, drawing in the vast majority of the bigger pathogens. Pathogens such as viruses and bacteria, on the other hand, are tiny enough to pass through the effective pore size of the obstructing zone.

Affixing viruses and bacteria to the skin Adsorption or adhesion of soil microorganisms may occur as a result of sticky coats or cellular appendages on soil microorganisms (Gerba, 1984).

Chemistry-induced changes in the viral capsid may result in the virus becoming dormant or opening the capsid and releasing the more readily degradable nucleic acid, depending on the situation (Yeager, 1979).

MoistureAs a general rule, infections are more likely to thrive in wet environments (Hurst, 1980; Gerba, 1984).

With a drop in soil moisture levels, pathogenic microorganisms may be inactivated by desiccation or predation may be increased as a result of a thinner moisture barrier around individual soil particles.

Freezing temperatures, on the other hand, may induce cellular damage and so reduce survival rates (Hurst, 1980; Gerba 1984).

Organic substances, on the other hand, may compete with viruses for adsorption sites (Gerba, 1984).

Thus, organic materials may promote viral transit and, as a result, negatively impact virus survival by blocking or reverseing adsorption, among other things.

Because of this, the facultative anaerobic bacteria of the gut are at a competitive disadvantage in an ecological niche that they have created.

Ciliated grazers, amoebae, rotifers, fungi, and aerobic bacteria are all examples of established microflora that may be found in the environment.

These pathogens include pH Salt ContentEnteric bacteria have been demonstrated to survive better in alkaline soils than in acidic soils, according to research.

Viruses and bacteria have surface charges that are depending on the pH of the environment.

The adsorption of cations, particularly multivalent cations, increases as the concentration of cations increases (Gerba, 1984).

The location of OSDSs is critical for their good operation and efficient microbial reduction.

For their part, clayey soils may not allow for adequate drainage, resulting in saturated and potentially anaerobic conditions.

A steep slope may enhance the flow rate via SAF, and the presence of surrounding bodies of water may result in seasonal saturated conditions in the SAF area.

Pathogen transfer is facilitated by saturated environments (Gerba, 1984).

SAMPLE CASE STUDIES FOR OSDS Polluted GROUNDWATEREpidemics associated with groundwater contaminated by OSDSs have been widely described in the literature for agents such as bacteria, viruses, and protozoa.

A total of 47 cases of cryptosporidiosis were documented as a result of the epidemic.

Two well shafts in a single aquifer were found to be responsible.

It was discovered that the second well had a cross connection with a SAF in the area.

The aquifer’s geology is composed primarily of sandstone, which appears to be slightly karstic in nature.

A total of around 1200 cases of shigellosis were documented from a local population of 6500 people throughout the outbreak.

It was discovered by a fluorescein dye test that an OSDS from a church was regularly polluting the source wells.

A Norwalk-related epidemic at a grade school impacted almost 72 percent of the children and instructors in the school.

The most likely source of water pollution was determined to be a back siphonage of sewage into the well through a cross connection with the OSDS, which was discovered (Taylor, 1981).

The following sections provide an overview of two example investigations.

The researchers used a network of observation wells to track the migration of naturally existing human enteroviruses from an OSDS through a shallow aquifer as part of their research.

Scandura and Sobsey conducted another investigation in which they assessed the performance of four different techniques for the elimination of bacterial and viral contamination.

The model enteric virus was injected into the septic tanks numerous times over the course of a year, and samples were taken from the septic tank, the distribution box, and the observation wells to be examined.

With the discovery of viral positives in a well 35 meters away from the distribution lines after just two days, further research indicated the possibility for quick and broad migration of viruses in the subsurface (Scandura, 1997).

To guarantee acceptable long-term performance in treating microbiological pathogens and other pollutants in sewage, on-site wastewater treatment systems must be sited, constructed, installed, operated, and maintained in accordance with the applicable codes and standards.

Robertson, Q Syed, N Speed, N Andrews, and P.R Hunter).

555-566 in Epidemiology and Infection, volume 115, number 5.

Groundwater Contamination from On-Site Septic Systems is a real possibility.

51, No.

12-16 in the Journal of Environmental Health.

Cliver published a paper in 1992 titled Biological inactivation of Poliovius Type 1 in a mixture of human and swine wastes as well as by bacteria isolated from swine manure In Applied and Environmental Microbiology, Vol.

6, pp.

Cliver published a paper in 1992 titled A study on the degradation of Giardia iamblia cysts in a mixture of human and pig wastes Pp.

58, No.

Deng, M.Y., and D.O.

Reachem, R.G., D.J.

Garelick, and D.D.

Excreta and Wastewater Management: Health Implications of Excreta and Wastewater Management.

The authors, C.P.

Bitton, wrote: Microbial Pollutants: Their Survival and Transport Patterns into Groundwater was published in 1984.

New York, New York: John Wiley & Sons, Inc.

Hagedorn, E.L.

Rahe published a paper titled Groundwater contamination from septic effluents was first identified in 1981, and it is still a concern today.

Hurst, C.J., Gerba, C.P., and Cech, I.


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1067-1079, the authors state that G.

Steinberg, and G.

Microbiology and Ecology, Vol.

251-260, FEMS Microbiology Ecology Reneau, R.B., C.

Degen published a paper in 1989 titled The fate and transport of biological and inorganic contaminants resulting from the on-site disposal of domestic wastewater are being investigated.

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Scandura, J.E., and M.D.

Volume 35, Number 11-12, pages 141-146.

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Greenberg published a paper in 1981 titled Gastroenteritis caused by Norwalk-associated virus as a result of contaminated drinking water Journal of Epidemiology and Community Health, Vol.

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Landry, and M.Z.

Transmission of viruses from Septic Tank Leach Fields through a Shallow Sandy Soil Aquifer is investigated.

Ward, R.L., et al.

Inactivation of viruses in Activated Sludege is caused by microorganisms, according to evidence.

Weissman, J.B., G.F.

Lawrence, R.A.

Saslaw, and E.J.

It has been determined that a contaminated public water supply is the source of an outbreak of Gastorentertisis.

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Yeager, J.G., and R.T.

Applied and Environmental Microbiology, Volume 38, Number 4, pages 694-701.

J.G. Yeager and R.T O’Brien, Structural Changes Associated with Poliovirus Inactivation in Soil, Applied and Environmental Microbiology, Vol. 38, No. 4, p. 702-709, 1979. Structural Changes Associated with Poliovirus Inactivation in Soil

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