Usually the disposal of effluent may be either underground or over ground. Normally underground disposal either in the form of soak pit or dispersion trenches is practised. Both the methods are designed to achieve subsurface percolation characteristics of the soil.
- Effluent flows out of the septic tank and is distributed into the soil through the leaching chamber system. The soil below the drainfield provides final treatment and disposal of the septic tank effluent. After the effluent has passed into the soil, most of it percolates downward and outward, eventually entering the shallow groundwater.
How is septic tank effluent is disposed?
Septic tank systems The liquid portion of the waste is disposed of through a drain field where natural filtering takes place in the soil. In areas where there is a high concentration of septic tanks, it is possible for pathogenic organisms to enter shallow ground waters or nearby surface waters.
How do you dispose of septic tank sludge?
Since all of the waste collected from a septic tank is organic, sending it away in a landfill is completely prohibited. However, the heavy sludge can be sent to a landfill by removing the liquid waste (this can be done only when the company has the permit to do so).
Which of the following methods are disposal of septic tank effluent *?
Explanation: By using a soak pit, Evapo-transpiration mound or leach field, the effluent of the septic tank must be dispersed or transported to another treatment technology via a solids-free sewer, simplified sewer or solids-free sewer.
Where does human waste go from septic tank?
In reality, most of the faecal sludge collected from septic tanks is dumped into rivers, drains and sewers or emptied untreated into agricultural fields and low-lying areas.
What is the type of effluent system?
Conventional effluent treatment systems are typically based on a series of water treatment facilities in which all the wastewater collected from water-using operations are combined and treated as a single effluent stream. This centralised approach treats wastewater collectively in sequence.
What is a common effluent system?
Common Effluent Disposal. Common Effluent Disposal (CED) is a sewage collection system that consists of septic tanks on each property. Each tank may be connected to the reticulation sewerage system, which conveys the sewage to either a centralised wastewater treatment plant or to a lagoon sewage treatment facility.
How do you tell if your septic tank is full?
Here are some of the most common warning signs that you have a full septic tank:
- Your Drains Are Taking Forever.
- Standing Water Over Your Septic Tank.
- Bad Smells Coming From Your Yard.
- You Hear Gurgling Water.
- You Have A Sewage Backup.
- How often should you empty your septic tank?
Can farmers empty septic tanks?
It isn’t possible to empty your sewage treatment plant or septic tank yourself, this should be done by a licenced carrier. However, it is possible to spread treated waste (sewage sludge) on your land. This can be from your own sewage treatment plant or (more likely) imported from elsewhere.
Which of the following is not the method of disposal of sewage from septic tank *?
5. Which of the following is not the method of disposal of sewage from septic tank? Explanation: Vacuum filter is used in the sludge dewatering process and upflow anaerobic filter, soil absorption system and biological filter are the method of disposal of sewage from the septic tank.
What is digestive chamber in septic tank?
In the specifications cited in the ordinance, septic tanks should have a 50 millimeter-diameter inlet where wastes from the toilets pass through that then leads to the first chamber called the digestive chamber.
Is codes for septic tank?
Indian standard code of practice for installation of septic tanks ( IS: 2470 ) – Bureau of Indian Standards (1986) This Code is dictated by the Bureau of Indian Standards, and ensures that the sewage is treated in a way that maintains health and hygiene of the community.
What happens to pumped septic waste?
In some cases, the septic contents are taken to waste treatment plants and added to the stew piped in from a municipal sewer system or delivered to independent, for-profit companies specializing in the treatment of septage.
Can I take a shower if my septic tank is full?
Only the water would get out into the leach field in a proper system unless you run too much water too fast. The thing to do is to run your shower water outside into it’s own drain area, but it may not be allowed where you are. Used to be called gray water system.
Where does waste drain to?
When the wastewater flushed from your toilet or drained from your household sinks, washing machine, or dishwasher leaves your home, it flows through your community’s sanitary sewer system to a wastewater treatment facility.
How Your Septic System Works
Underground wastewater treatment facilities, known as septic systems, are often employed in rural regions where there are no centralized sewage lines. They clean wastewater from residential plumbing, such as that produced by bathrooms, kitchen drains, and laundry, by combining natural processes with well-established technology. A conventional septic system is comprised of two components: a septic tank and a drainfield, often known as a soil absorption field. It is the septic tank’s job to decompose organic matter and to remove floatable stuff (such as oils and grease) and solids from wastewater.
Alternate treatment systems rely on pumps or gravity to assist septic tank effluent in trickling through a variety of media such as sand, organic matter (e.g., peat and sawdust), constructed wetlands, or other media to remove or neutralize pollutants such as pathogens that cause disease, nitrogen, phosphorus, and other contaminants.
Specifically, this is how a typical conventional septic system works:
- All of the water that leaves your home drains down a single main drainage pipe and into a septic tank. An underground, water-tight container, often composed of concrete, fiberglass, or polyethylene, serves as a septic system’s holding tank. Its function is to retain wastewater for a long enough period of time to allow particles to sink to the bottom and form sludge, while oil and grease float to the surface and produce scum. Sludge and scum are prevented from exiting the tank and moving into the drainfield region by compartments and a T-shaped outlet. After that, the liquid wastewater (effluent) exits the tank and flows into the drainfield. The drainfield is a shallow, covered hole dug in unsaturated soil that serves as a drainage system. Porous surfaces are used to release pretreated wastewater because they allow the wastewater to pass through the soil and into the groundwater. In the process of percolating through the soil, wastewater is accepted, treated, and dispersed by the soil, finally discharging into groundwater. Finally, if the drainfield becomes overburdened with too much liquid, it can flood, causing sewage to flow to the ground surface or resulting in toilet backups and sink backups. Finally, wastewater percolates into the soil, where it is naturally removed of harmful coliform bacteria, viruses, and nutrients. Coliform bacteria are a kind of bacteria that may be found in the intestines of humans and other warm-blooded animals, with humans being the most common host. As a result of human fecal contamination, it is a sign of this.
The Guadalupe-Blanco River Authority has built an animated, interactive model of how a residential septic system works, which you can view here.
Do you have a septic system?
It’s possible that you’re already aware that you have a septic system. If you are not sure, here are some tell-tale symptoms that you most likely are:
- You make use of well water. In your home, the water pipe that brings water into the house does not have a meter. In the case of a water bill or a property tax bill, you will see “$0.00 Sewer Amount Charged.” It is possible that your neighbors have a septic system
How to find your septic system
You can locate your septic system once you have confirmed that you have one by following these steps:
- Taking a look at the “as constructed” drawing of your house
- Making a visual inspection of your yard for lids and manhole covers
- Getting in touch with a septic system service provider for assistance in locating it
Failure symptoms: Mind the signs!
A bad odor is not necessarily the first indicator of a septic system that is failing to work properly. Any of the following signs should prompt you to seek expert assistance:
- Water backing up into the drains of homes and businesses
- It is especially noticeable in dry weather that the drainfield grass is bright green and spongy. The presence of standing water or muddy soil near your septic system or in your basement
- A strong stench emanating from the area surrounding the septic tank and drainfield
Septic Systems Overview
Over one-fifth of all American houses rely on individual sites or small community cluster systems (septic systems) to treat their wastewater, according to the Environmental Protection Agency. Modest-scale wastewater treatment and disposal systems are used to treat and dispose of relatively small quantities of wastewater, which are often generated by households and businesses in suburban and rural areas that are not served by a major public sewage system. Wastewater from residential plumbing fixtures (toilet, shower, and laundry) is treated using both natural and technical processes in septic systems, with the process often starting with sediments settling in the tank and concluding with wastewater treatment in the soil via a drainfield.
Septic systems are also referred to as:
- On-site wastewater treatment systems, decentralized wastewater treatment systems, cluster systems, package plants, on-lot wastewater treatment systems, individual sewage disposal systems, and private sewage systems are all options.
The many methods of decentralized wastewater treatment, when correctly implemented, may safeguard public health, preserve important water resources, and help a community retain its economic vibrancy while also reducing costs.
The use of these technologies for wastewater treatment, particularly in less densely inhabited areas, is both cost-effective and long-term.
- Highlights from the Decentralized Wastewater Management Program’s Annual Report for 2013
What are the benefits of using septic systems to manage wastewater from small communities?
- Benefits to the general public’s health Decentralized systems, when used properly, limit the danger of disease transmission and human exposure to pathogens, which can occur as a result of contaminated drinking water, surface water, or shellfish beds. -Wastewater treatment reduces contaminants from surface water, recharges groundwater, and refills aquifers, among other advantages. Advantages in terms of economics – Decentralized wastewater systems assist communities in reducing substantial infrastructure and energy expenses associated with collecting and treating wastewater.
Are septic systems more prevalent in some areas of the country?
According to the United States Census Bureau, the distribution and density of septic systems varies greatly by area and state, with a high of around 55 percent in Vermont and a low of approximately 10 percent in California, respectively.
- The New England states have the greatest proportion of households served by septic systems in the country, according to the EPA. Individual systems serve around one-half of all residences in New Hampshire and Maine, according to state statistics. Homes in the southeastern states rely on these systems in greater numbers than one-third of the time. This includes roughly 48 percent of homes in North Carolina and over 40 percent in both Kentucky and South Carolina. Septic systems provide service to more than 60 million people in the United States. The treatment of approximately one-third of all new development is provided by septic or other decentralized treatment systems.
Do septic systems cause health or water quality problems?
In the right circumstances, septic systems may provide excellent wastewater treatment when they are planned, developed, installed, managed, and maintained appropriately. Systems that are sited at densities that exceed the treatment capability of area soils, as well as systems that are poorly planned, installed, operated, or maintained, can, on the other hand, cause issues. The pollution of surface waterways and ground water with disease-causing microorganisms and nitrates is one of the most significant known concerns in recent history.
Disease infections are contaminating critical shellfish beds and swimming beaches in several coastal locations, which is a source of concern.
How are septic systems regulated?
Construction and operation licenses for septic systems are issued by municipal health departments in most states, in accordance with state laws governing public health protection and the abatement of public nuisances, respectively. Because of the potential consequences of nitrogen and phosphorus runoff, several states have included measures for water resource preservation in their septic system rules. In most regulatory programs, the local permitting agency conducts a site evaluation to establish if the soils can offer enough treatment for the pollutants being treated.
When conventional soil-based systems are not feasible, several governments allow for the use of alternate methods.
On-site wastewater treatment systems are subject to regulation.
- Individual on-site systems are governed by state, tribal, and municipal laws
- However, there is no federal regulation. Large capacity septic systems are controlled by the Environmental Protection Agency’s Safe Drinking Water Act Underground Injection Well program, which sets forth the standards for large capacity septic systems. Systems that discharge pollutants into surface waterways are controlled by the Environmental Protection Agency’s National Pollutant Discharge Elimination System program, which is part of the Clean Water Act. Sludge disposal (also known as biosolids) and household septage disposal are governed by the Environmental Protection Agency’s sewage sludge rule (PDF)(1 page, 107 K,About PDF)(40 CFR Part 503).
- EPA Part 503 Regulation: A Guide to Biosolids Risk Assessment covers the risk assessment approach that served as the foundation for the biosolids rule.
What terms are commonly used when talking about Septic Systems?
The Environmental Protection Agency’s Glossary of Septic System Terminology comprises words typically used in the wastewater treatment sector, as well as meanings for each phrase.
31st of May, 2019 Eawag is the author and compiler of this work (Swiss Federal Institute of Aquatic Science and Technology) Dorothee Spuhler is a well-known author (seecon international gmbh)
An underground chamber built of brick, concrete, fiberglass, PVC, or plastic, into which blackwater from cistern or pour-flush toilets and greywater from a conduit running from within a structure or an outdoor toilet is sent for initial treatment, is known as a septic tank. Solids and organics are reduced through settling and anaerobic processes, although the treatment is only modest in effectiveness. Effluent is either absorbed into the ground or carried to a (semi-)centralised treatment facility through a sewer system.
- Advantages Can be constructed and restored using materials that are readily available in the area.
- Technology that is simple and reliable There is no requirement for electrical energy.
- Operational costs are low.
- Low decrease in pathogens, solids, and organics is necessary to transport the waste to the treatment unit.
- This material is only appropriate for low-density dwellings in places with a low water table that are not prone to floods.
Manual cleaning of the tank is a dangerous and cruel work, whereas mechanical cleaning (vacuum trucks) necessitates the use of advanced tools and equipment. Effluent and sludge require additional treatment and/or disposal in a suitable manner.
|Blackwater,Brownwater,Greywater||Blackwater (settled, Effluent), Faecal Sludge, (Biogas)|
The Body of the Factsheet Among small-scale decentralised treatment units for grey water and blackwater from cistern or pour-flush toilets, the most commonly seen is the septic tank. It functions primarily as a sedimentation tank. It can be either rectangular or cylindrical in form. Septic tanks are often used for wastewater with a high concentration of settleable particles, such as effluent from home sources, but they can also be used for other types of wastewater with comparable characteristics (SASSE 1998).
- Anaerobic degradation occurs as a result of the accumulation of sediments at the bottom of the tank over time.
- The effluent from the septic tank must be distributed by means of aSoak Pit, an evapo-transpiration mound, or a Leach Field, or it must be conveyed to another treatment technology by means of aSolids-Free Sewer, a simplified sewer, or a solids-free sewer system.
- In order to dispose of or reuse sludge safely, it must be emptied on a regular basis (see also human-poweredemptying and motorizedemptying).
- It is possible to use sewage sludge in agriculture as a good nutrient-rich soil additive if it has been dried or composted (see alsopplication of pit humus and compostorapplication of sludge).
- Generally, when septic tanks are utilized as the primary settling treatment in DEWATS systems, they are followed by anaerobic filters, anaerobic baffled reactors (ABRs), horizontal, surface flow, or vertical flow built wetlands (planted gravel filters), and maturation ponds (if applicable).
- An illustration of a septic tank’s general layout.
- The biogas produced during anaerobic digestion can be expelled through a venting pipe.
- coli removal rates of one log can all be expected in a properly designed and maintained septic tank, though actual removal rates can vary greatly depending on operating and maintenance practices as well as environmental conditions.
The Body of the Factsheet Concrete or brick work should be used to construct at least two chambers in a sewage treatment system. PVC or fibreglass septic tanks, as well as pre-fabricated concrete rings are also available and may be more cost-effective in some situations (WSP 2008). The first chamber should account for at least half of the overall length (SASSE 1998), and if there are only two chambers, the first chamber should account for two-thirds of the total length (SASSE 1998) The majority of the solids are concentrated in the first chamber.
- The use of a T-shaped outlet pipe, with the bottom arm of the pipe diving 30 cm below the water surface (SASSE 1998), helps to further minimize the amount of scum and particles released.
- When the flow is smooth and undisturbed, sedimentation can provide the most effective physical therapy possible.
- Different treatment effects prevail depending on how the incoming influent flows through the tank during the initial treatment.
- As active materials that have not been entirely fermented exit the tank, foul odors are produced as a result (SASSE 1998).
- It is necessary to allow for the escape of the gases created during anaerobic digestion.
- If the drainage system is not vented, a screened vent pipe should be installed from the septic tank to the outside environment (WHO 1992).
- Source: Environmental Protection Agency of the United States (n.y.) It is important to have access to all chambers (through access ports) in order to do maintenance.
- The design of a septic tank is influenced by the number of users, the amount of water used per capita, the average yearly temperature, the frequency of desludging, and the properties of the effluent being treated (SASSE 1998).
- According to SASSE (1998), a tank volume of around 80 to 100 L should be given per residential user, however most nations have a national requirement for tank volume per domestic user.
- If you want to attain modest results, you need keep the patient for 48 hours.
- Sources: U.S.
coli (a fecal indicator bacteria) (TILLEY et al. 2008), although efficacy varies greatly depending on influent concentrations and climatic conditions (UNEP 2004). If you want to attain modest results, you need keep the patient for 48 hours.
An Aquaprivy is a type of septic tank that is a variant on the standard design. This is a basic storage and settling tank that is situated just below the toilet, allowing the excreta to fall into it through a line that leads to the toilet. When the bottom of the pipe is submerged in a liquid in the tank, it forms a water seal, which keeps flies, mosquitoes, and odors from escaping (WHO 1992). The tank performs the same duties as a septic tank. The wastewater is normally infiltrated into the ground through a soak pit, and the solids (sludge) that build must be cleaned on a regular basis (WHO 1992).
The Aquaprivy has a low efficiency in terms of therapy.
WAaF is the source (2002)
The Body of the Factsheet The influent and effluent are kept separate under normal operating circumstances so that consumers are not exposed to them. Several difficulties associated with septic tank systems develop as a result of a failure to pay proper thought to the disposal of the tank effluent. Because septic tank effluent is anaerobic, it is likely to contain a significant number of germs, which can be a source of infection for those who come into contact with it (WHO 1992). Because they contain high amounts of harmful organisms, effluent, scum, and sludge must be treated with caution when they are generated.
When opening the tank, users should exercise caution since toxic and combustible gases may be emitted into the environment.
Factsheet Block BodySeptic tank construction costs are quite modest when compared to the costs of other water-based systems. However, they are significantly more expensive than dry toilets or composting toilets, making them unaffordable for the majority of individuals in our society. There must also be enough piped water to flush all of the wastes through the drains, and human or mechanical de-sludging (using a vacuum or a gulper) de-sludging must be performed on a regular basis. Engineers are required to develop the design and plan, while untrained laborers can carry out the building work provided a mason oversees the project.
The Body of the Factsheet Septic tanks should be “seeded” with sludge from another tank that has been in operation for some time in order to ensure that the required bacteria responsible for anaerobic digestion are present when the tank is first started (WHO 1992). Because of the fragile ecosystem, it is important to avoid discharging harsh chemicals into the septic system. The levels of scum and sludge in the tank must be checked to verify that the tank is operating properly. De-sludging is required when sludge and scum occupy half to two-thirds of the entire depth between the water level and the bottom of the tank, as measured above the water level (WHO 1992).
- Septic tanks should be drained on a regular basis, usually every 2 to 5 years.
- This is an unpleasant job, and care must be taken to ensure that sludge does not spill around the tank during the emptying process.
- faecal sludge must be dehydrated (see also planted or unplanted drying beds, settling or thickening ponds) and further processed before it can be used (e.g.smallorlarge scalecomposting,anaerobic digestion).
- It is recommended that the separated effluents from these systems be treated in waste stabilisation ponds (WSP) or built wetlands (CW) (surface flow,horizontalorvertical flow).
- The integrity of septic tanks should be tested on a regular basis to ensure that they are not leaking.
It is also important to conduct routine inspections in order to remove floating debris such as coarse materials and grease, to verify that there are no obstructions at the inlet or exit, and to determine whether de-sludging is required.
At a Glance
The Body of the Factsheet
|Working Principle||Basically a sedimentation tank (physical treatment) in which settled sludge is stabilised by anaerobic digestion (biological treatment). Dissolved and suspended matter leaves the tank more or less untreated.|
|Capacity/Adequacy||Household and community level; Primary treatment for domestic grey- and blackwater. Depending on the following treatment, septic tanks can also be used for industrial wastewater. Not adapted for areas with high groundwater table or prone to flooding.|
|Performance||BOD: 30 to 50%; TSS: 40 to 60 %; E. coli: 1 log unitsHRT: about 1 day|
|Costs||Low-cost, depending on availability of materials and frequency of de-sludging.|
|Self-help Compatibility||Requires expert design, but can be constructed with locally available material.|
|O M||Should be checked for water tightness, scum and sludge levels regularly.Sludgeneeds to be dug out every 1 to 5 years and discharged properly (e.g. in composting or drying bed). Needs to be vented.|
|Reliability||When not regularly emptied, wastewater flows through without being treated. Generally good resistance to shock loading.|
|Main strength||Simple to construct and to operate.|
|Main weakness||Effluentand sludge require further treatment. Long start-up phase.|
Applicability The majority of the time, this technology is utilized at the home level. The design of larger, multi-chamber septic tanks for groups of residences or public buildings can be accomplished by combining many chambers (e.g., schools). A septic tank is ideal in situations when there is a means of dispersing or transferring the sewage away from the property. Septic tank effluents can be penetrated into the soil and stored in soak pits, aleach fields, or mounds. Due to the presence of pathogens in the effluent, it should not be utilized for agricultural irrigation and should not be released into canals or surface water drains (WHO 1992).
Septic tanks should be connected to some form of conveyance technology (such as a simplified sewer or a solids-free sewer), via which the effluent is transferred to a later Treatment or Disposal site, rather than being used alone (e.g.surface flow,horizontalorvertical flowconstructed wetlands).
- Because the septic tank must be desludged on a regular basis, it is necessary for a vacuum truck to be able to reach the site.
- Every sort of environment may accommodate septic tanks, albeit the efficiency of these tanks will be reduced in colder climes.
- However, they must be emptied on a regular basis and require ongoing upkeep (TILLEY et al.
- Material for Raising Awareness
Alternative Versions to
When a household isn’t connected to a public sewage system, it normally relies on septic systems to treat and dispose of wastewater. Sewage treatment systems require a substantial financial commitment. The correct maintenance and upkeep of a well-designed, installed, and maintained system will provide years of dependable and low-cost service. The failure of a system can become a source of pollution and public health concern, resulting in property damage, ground and surfacewater pollution (such as contamination of well water used by you and your neighbors), and the spread of disease.
Aside from that, if you are planning to sell your property, your septic system has to be in good functioning order.
Septic systems are available in a variety of configurations to accommodate a wide range of soil and site conditions.
Understanding the major components of a typical (gravity-fed) septic system, as well as how to maintain it working properly and at the lowest possible cost, can help you make the best decision possible. A conventional septic tank system is composed of three major components:
- This is known as the Septic Tank. In order to remove particles from wastewater, store and partially decompose as much solid material as possible, while allowing the liquid (or effluent) to flow to the drainfield, a septic tank must be installed. more
- The Drainage System After the particles have settled in the septic tank, the liquid wastewater (also known as effluent) is released to the drainfield, which is also known as an absorption or leach field, or both. more
- The Soil is a very important factor. The soil under the drainfield is responsible for the ultimate treatment and disposal of the septic tank effluent once it has been treated. Following the passage of wastewater into the soil, organisms in the soil remediate the effluent before it percolates downward and outward, eventually entering ground or surface water sources. A drainfield’s efficacy is also affected by the kind of soil
- For example, clay soils may be too tight to allow much wastewater to run through, while gravelly soil may be too coarse to give much treatment.
- Septic System Inspection Done at Home In order to aid you in examining your system, a VideoField Guide and Checklist may be available at the bottom of the homepage.
Homeowners and residents have a significant impact on the functioning of their septic systems. Overloading the system with more water than it is capable of handling might result in system failure. A septic system can also be damaged by the improper disposal of chemicals or excess organic waste, such as that produced by a trash disposal. The following maintenance suggestions might assist you in ensuring that your system provides long-term, effective treatment of domestic waste.
Inspect and Pump Frequently
The most critical step in keeping your septic tank in good working order is to eliminate sludge and scum build-up before it may flow into the drainfield. The frequency with which your tank has to be pumped is determined by the size of the tank, the number of people in your family, the quantity of water utilized, and the amount of solids (from humans, garbage disposal, and any other waste) that enter the tank’s drainage system. Tanks should be pumped out on average every 3 to 5 years, depending on usage.
- Septic Inspection and Pumping Guide
- Inspecting Your Septic Tank
- Septic Inspection and Pumping Guide
Use Water Efficiently
System failure is frequently caused by an excessive amount of water. The soil beneath the septic system must be able to absorb all of the water that is used in the residence. Too much water from the washing machine, dishwasher, toilets, bathtubs, and showers may not provide enough time for sludge and scum to separate properly in the drain. The less water that is consumed, the less water that enters the septic system, reducing the likelihood of system failure. For further information on water conservation, visit:
- Indoor Water Conservation
- Every gallon of water conserved equates to a savings of $1.00.
Minimize Solid Waste Disposal
What you flush down the toilet can have a significant influence on the performance of your septic system. Many things do not breakdown properly, and as a result, they accumulate in your septic tank. If you have the option of disposing of it in another manner, do so rather than introducing it into your system.
Keep Chemicals Out of Your System
Protect your septic system against home chemicals such as caustic drain openers, paint and pesticides. Also avoid flushing down the toilet with chemicals such as brake fluid, gasoline, and motor oil. The improper dumping of dangerous substances down the drain is damaging to the environment, as well as the bacteria that are necessary for the breakdown of wastes in a septic system, and should be avoided.
Septic System Additives
It is not essential to add a stimulant or an enhancer to a septic tank in order to assist it in functioning or “to restore bacterial equilibrium.” The naturally occurring bacteria required for the proper operation of the septic system are already present in human excrement. Septic systems, like automobiles, are designed to offer long-term, effective treatment of residential waste if they are properly run and maintained on a regular basis. The majority of systems that fail prematurely, on the other hand, are the result of poor maintenance.
If you see any of the indicators listed below, or if you have reason to believe your septic system is experiencing issues, call a trained septic technician immediately. In the event that your septic system fails, call Thurston County Environmental Health at 360-867-2673 for assistance.
- Odors, surface sewage, moist areas, or a dense growth of plants in the drainfield region are all possible problems. Backups from the plumbing or septic tank (which are often a dark liquid with a foul odor)
- Fixtures that take a long time to drain
- The plumbing system is making gurgling sounds. Your drainfield may be failing if you have a well and tests reveal the presence of coliform (bacteria) or nitrates in the water from it. Even in the midst of a drought, the drainfield is covered with lush green grass.
How Often Are Septic Tanks Emptied, and Where Do the Contents Go?
It’s safe to assume that wherever there are many individuals who run their houses’ waste systems through septic tanks, there will be a slew of local firms that specialize in eliminating the scum and sludge that collect in the tank over a long period of time. This is a crucial service because, if too much sludge accumulates over time, it can cause overflow, which is harmful to everyone involved. Septic pumping for commercial purposes typically consists of a pump truck emptying the sludge, effluent, and scum from the tank and leaving the tank empty and ready to be refilled with fresh sludge and water.
- Prior to the passage of federal legislation prohibiting the disposal of sewage sludge, waste management businesses could simply bury it in landfills.
- These locations still exist, however many of them are in the process of being cleaned up (clean-up).
- In certain situations, the septic contents are transported to waste treatment plants where they are combined with the stew that has been pumped in from a municipal sewer system, or they are supplied to for-profit organizations that specialize in the treatment of septage.
- Septage may also be placed at landfills that have been allowed.
- Because of the difficulties associated with properly disposing of your septic tank’s contents, septage is sometimes employed in a different way: to grow food.
- This application of septage has the potential to be contentious.
- It is expected that, when properly applied to farmland with good soil and a low water table, the soil will work as a filter in the same way as a drain field in the rear of a home with a septic tank will act as a filter.
- Historically, it has been recognized that methane, which is created as a waste product during the breakdown of sewage, may be utilized to generate energy.
- In addition, because the power produced does not burn, there is little or no pollutants emitted.
- One system, constructed south of Seattle, Washington, in 2004, has the capacity to generate enough electricity to power 1,000 houses.
Who would have thought that your feces could be so beneficial? More information about waste treatment may be found on the next page. The original publication date was July 29, 2008.
Septic System Information and Care
When municipal sewer service is not available, a septic system that has been properly constructed and maintained is an excellent option for treating wastewater and protecting groundwater quality. A typical septic system is comprised of two key components: the septic tank and the drainfield (or leach field). Waste from toilets, sinks, washing machines, and showers is channeled into a septic tank, which is a holding tank that is typically constructed of pre-cast concrete or fiberglass and is proportioned according to the projected wastewater flow from a given-sized house or commercial establishment.
- In the first stage of wastewater treatment, anaerobic bacteria (bacteria that can survive in an oxygen-free environment) break down solids into liquids and generate gas that is vented through the building’s plumbing vent stack.
- The lack of oxygen inside the septic tank also has the added benefit of deactivating some of the disease bacteria that are prevalent in sewage.
- Because it allows aerobic (oxygen-using) bacteria to continue deactivating the disease germs that remain in the wastewater, the drainfield serves as a secondary treatment facility for sewage.
- Evaporation of water also occurs through the layer of soil that surrounds the drainfield.
- That way, enough permeable or unsaturated soil is available to filter the wastewater before the remainder of it gets into the groundwater table and underlying aquifer.
- In certain instances, modern wastewater treatment systems that “aerate,” or add oxygen to the wastewater, may be necessary to treat the effluent.
Septic System Care
Don’t flush cigarette butts, tampons, condoms, or any other indigestible things down the toilet or down the sink drain. Consequently, the exit filter or drainfield will become clogged. Never throw grease down the drain since grease cannot be digested by the septic system and will cause it to become clogged! rather than dumping it in the garbage, pour it into an empty container or bottle and throw it away. Make sure you don’t use excessive amounts of bleach or other cleaning agents in your septic tank since doing so will interfere with the bacterial operation inside the tank.
- Instead of doing numerous loads of laundry back-to-back, stretch your wash loads out over the course of the week to reduce the amount of water that the septic system has to treat (a normal wash load consumes between 60 and 90 gallons each load!).
- Roots from trees and plants will grow into the drainlines and cause them to get obstructed.
- Driving over your drainfield can cause the pipes to become crushed or the dirt surrounding them to become compacted, and driving over your septic tank can cause the lid to fracture or even fall apart!
- Consider the installation of water-saving showerheads, toilets, and other water-saving appliances in your home.
- Septic tanks should be pumped out every four to five years, according to the Florida Department of Health, in order to prevent the buildup of sludge in the tank over time.
- Stoppages and overcrowded drainfields are caused by leaking toilet flapper valves, which can allow hundreds of thousands of gallons of waste water to enter your septic system each day.
- In addition to providing you with many useful suggestions and information, our Environmental Health Professionals can also assist you extend the life of your existing septic system.
If you would like more information on the operation of traditional or sophisticated wastewater treatment systems, or if you have any questions about maintaining your septic system, please call us at (386) 758-1058.
Septic Tank Everything that goes down any of the drains in the house
|Septic TankEverything that goes down any of the drains in the house (toilets, showers, sinks, laundry machines) travels first to the septic tank. The septic tank is a large-volume, watertight tank which provides initial treatment of the household wastewater by intercepting solids and settleable organic matterbefore disposal of the wastewater (effluent) to the drainfield.Function of the Septic TankHow Long Liquids Must Remain In TankSolids StorageAnaerobic DecompositionFlow Into And Out Of The TankEffluent FilterFlow BufferingMicrobes in Septic Tanks Digest, Dissolve, and Gasify Complex Organic Wastes.FUNCTION OF THE SEPTIC TANK While relatively simple in construction and operation, the septic tank provides a number of important functions through a complex interaction of physical and biological processes. The essential functions of the septic tank are to: receive all wastewater from the house separate solids from the wastewater flow cause reduction and decomposition of accumulated solids provide storage for the separated solids (sludge and scum) pass the clarified wastewater (effluent) out to the drain field for final treatment and disposal.Primary TreatmentAs stated, the main function of the septic tank is to remove solids from thewastewater and provide a clarified effluent for disposal to the drain field.The septic tank provides a relatively quiescent body of water where thewastewater is retained long enough to let the solids separate by bothsettling and flotation. This process is often called primary treatment andresults in three products: scum, sludge, and effluent.Scum: Substances lighter than water (oil, grease, fats) float to the top,where they form a scum layer. This scum layer floats on top of the watersurface in the tank. Aerobic bacteria work at digesting floating solids.Sludge: The “sinkable” solids (soil, grit, bones, unconsumed food particles)settle to the bottom of the tank and form a sludge layer. The sludge isdenser than water and fluid in nature, so it forms a flat layer along thetank bottom. Underwater anaerobic bacteria consume organic materials in thesludge, giving off gases in the process and then, as they die off, becomepart of the sludge.Effluent: Effluent is the clarified wastewater left over after the scum hasfloated to the top and the sludge has settled to the bottom. It is theclarified liquid between scum and sludge. It flows through the septic tankoutlet into the drain field.Back to listingsHOW LONG LIQUIDS MUST REMAIN IN TANK Effective volume: The floating scum layer on top and the sludge layer on thebottom take up a certain amount of the total volume in the tank. Theeffective volume is the liquid volume in the clear space between the scumand sludge layers. This is where the active solids separation occurs as thewastewater sits in the tank.Retention time: In order for adequate separation of solids to occur, thewastewater needs to sit long enough in the quiescent conditions of the tank.The time the water spends in the tank, on its way from inlet to outlet, isknown as the retention time. The retention time is a function of theeffective volume and the daily household wastewater flow rate:Retention Time (days) = Effective Volume (gallons)/Flow Rate (gallons per day)A common design rule is for a tank to provide a minimum retention time ofat least 24 hours, during which one-half to two-thirds of the tank volume istaken up by sludge and scum storage. Note that this is a minimum retentiontime, under conditions with a lot of accumulated solids in the tank. Underordinary conditions (i.e., with routine maintenance pumping) a tank shouldbe able to provide two to three days of retention time.As sludge and scum accumulate and take up more volume in the tank, theeffective volume is gradually reduced, which results in a reduced retentiontime. If this process continues unchecked-if the accumulated solids are notcleaned out (pumped) often enough-wastewater will not spend enough time inthe tank for adequate separation of solids, and solids may flow out of thetank with the effluent into the drain field. This can result in clogged pipesand gravel in the drain field, one of the most common causes of septic systemfailure.Back to listingsSOLIDS STORAGE In order to avoid frequent removal of accumulated solids, the septic tank is(hopefully) designed with ample volume so that sludge and scum can be storedin the tank for an extended period of time. A general design rule is thatone-half to two-thirds of the tank volume is reserved for sludge and scumaccumulation. A properly designed and used septic system should have thecapacity to store solids for about five years or more. However, the rate ofsolids accumulation varies greatly from one household to another, and actualstorage time can only be determined by routine septic tank inspections.Back to listingsANAEROBIC DECOMPOSITION While fresh solids are continually added to the scum and sludge layers,anaerobic bacteria (bacteria that live without oxygen) consume the organicmaterial in the solids. The by-products of this decomposition are solublecompounds, which are carried away in the liquid effluent, and various gases,which are vented out of the tank via the inlet pipe that ties into the houseplumbing air vent system.Anaerobic decomposition results in a slow reduction of the volume ofaccumulated solids in the septic tank. This occurs primarily in the sludgelayer but also, to a lesser degree, in the scum layer. The volume of thesludge layer is also reduced by compaction of the older, underlyingsludge. While a certain amount of volume reduction occurs over time, sludgeand scum layers gradually build up in the tank and eventually must be pumpedout.Back to listingsFLOW INTO AND OUT OF THE TANK The inlet and outlet ports of the tank are generally equipped with devicessuch as baffles, concrete tees, or in more recent years, sanitary tees(T-shaped pipes with one short and one long leg).InletsThe inlet device dissipates the energy of the incoming flow and deflects itdownwards. The vertical leg of the tee extends below the liquid surface wellinto the clear space below the scum layer. This prevents disturbance of thefloating scum layer and reduces disruptive turbulence caused by incomingflows. The inlet device also is supposed to prevent short-circuiting offlows across the water surface directly to the outlet.The upper leg of the inlet should extend well above the liquid surface inorder to prevent floating scum from backing up into, and possibly plugging,the main inlet pipe. The open top of the inlet tee allows venting of gasesout of the tank through the inlet pipe and fresh air vents of the householdplumbing.OutletsThe outlet device is designed to retain the scum layer within the tank. Asanitary tee can be used with the lower leg extending below the scum layer.The elevation of the outlet port should be 2 to 3 inches below the elevationof the inlet port. This prevents backwater and stranding of solids in themain inlet pipe during momentary rises in the tank liquid level caused bysurges of incoming wastewater.Typical inlet/outlet teesGas Deflection BaffleGases are produced by the natural digestion of sludge at the bottom of thetank, and particles of sludge can be carried upward by these rising gases.Some tanks have a gas deflection baffle, which prevents gas bubbles (towhich solid particles often adhere) from leaving the tank by deflecting themaway from the outlet and preventing them from entering the drain field.Back to listingsTHE EFFLUENT FILTER In newer systems, there is often an effluent filter: one of the significantimprovements in septic tank design in decades. They range from 4 to 18inches in diameter. As we have described, the most serious problem withseptic systems is the migration of solids, grease, or oil into thedrain field, and the filter is effective in preventing this.A filter restricts and limits passage of suspended solids into the effluent.Solids in a filtered system’s effluent discharge are significantly less thanthose produced in a non-screened system.Back to listingsFLOW BUFFERING The septic tank also provides a buffering of flows between the house and thedrain field. Large surges from the household, such as toilet flushing orwashing machine drainage, are dampened by the septic tank so that the flowsleaving the tank and entering the drain field are at substantially lower flowrates and extend over a longer period of time than the incoming surges.Back to listingsMICROBES IN SEPTIC TANKS DIGEST, DISSOLVE, AND GASIFY COMPLEX ORGANIC WASTES In 1907, W. P. Dunbar conducted tests on the decomposition of vegetable andanimal matter in septic tanks. He stated, “The author has investigated thesubject by suspending in septic tanks a large number of solid organicsubstances, such as cooked vegetables, cabbages, turnips, potatoes, peas,beans, bread, various forms of cellulose, flesh in the form of dead bodiesof animals, skinned and unskinned, various kinds of fat, bones, cartilage,etc., and has shown that many of these substances are almost completelydissolved in from three to four weeks. They first presented a swollenappearance, and increased in weight. The turnips had holes on the surface,which gradually became deeper. The edges of the cabbage leaves looked asthough they had been bitten, and similar signs of decomposition were visiblein the case of other substances. Of the skinned animals, the skeleton aloneremained after a short time; with the unskinned animals the process lastedrather longer. At this stage I will only point out that the experiments wereso arranged that no portion of the substances could be washed away; theirdisappearance was therefore due to solution and gasification.”Back to listings|
Understanding Septic Systems
On-site (unsewered) systems are used to dispose of domestic wastewater in more than 25 million houses, accounting for about a quarter of the population of the United States. According to the American Housing Survey for the United States, in 1993, 1.5 (million) out of every 4 (million) new owner-occupied home starts relied on some sort of onsite sewage disposal, according to the American Housing Survey. When comparing the ownership of an unsewered vs a sewered house, one of the most significant distinctions is that unsewered wastewater treatment and disposal systems must be maintained by the homeowner.
Using an onsite disposal system is the most prevalent method of treating and disposing of wastewater in rural residences.
Septic systems account for the vast majority of onsite waste disposal systems in the United States.
Typical Septic System
- Access ports, distribution box, 4″ perforated pipe, absorption field, crushed rock or gravel lined trench, septic tank
How It Works
A typical septic system is comprised of two key components: a septic tank and an absorption field, both of which are shown in the diagram. Distribution boxes are frequently incorporated as part of the system to distribute septic tank effluent uniformly into the absorption field, which is comprised of a network of distribution lines that connect to the absorption field. The septic tank is normally constructed of concrete or fiberglass, is underground, and must be completely waterproof in order to function properly.
Two-compartment tanks are the most common type of septic tank, followed by two single compartment tanks in sequence.
Cross-section of a two-compartment septic tank
A sewage tank’s capacity is normally built to contain 750 to 1,800 gallons of sewage, although it may be customized based on the number of bedrooms in the house and state and local regulatory regulations. In its most basic form, the septic tank serves to filter solids from liquids while also encouraging partial breakdown of pollutants by microbes that are naturally present in the wastewater to achieve the desired results. The particles, which are referred to as sludge, settle in the bottom of the tank, while the scum floats on top of the liquid at the top of the tank.
- Solids that are permitted to flow through the septic tank and into the absorption field might block the absorption field.
- Because of this, the installation of effluent filters at the septic tank outflow provides an extra layer of protection in the effort to keep particles out of the absorption area.
- The effluent is sent to the absorption field through a connecting pipe or distribution box, depending on the configuration.
- Typically, the absorption field is composed of a network of underground perforated pipes or some other proprietary distribution system.
- The absorption field, which is located in the unsaturated zone of the soil, treats the wastewater by utilizing physical, chemical, and biological processes to treat the waste water.
As an added benefit, the soil serves as a natural buffer, removing many hazardous bacteria, viruses, and excessive nutrients from the wastewater as it flows through the unsaturated zone before it reaches the groundwater supply.
- Well for drinking water
- Septic tank
- Distribution box
- Absorption field
- Soil absorption (unsaturated zone)
- Groundwater (saturated zone)
- And other structures.
Wastewater treatment and disposal in soil
In excess, wastewater includes nutrients such as nitrates and phosphates, which can contaminate neighboring streams and groundwater sources, as well as the environment. Extra nutrients in drinking water sources may be damaging to human health and can damage lakes and streams by encouraging weed growth and algal blooms, both of which are detrimental to the environment. But many of these nutrients can be retained in the soil, where they are eventually taken up by the surrounding flora.
What to put in, what to keep out
- All wastewater from your house should be sent into the septic tank. Alternatively, graywater might be channeled to a mulch basin irrigation system or a disposal field. Maintain a safe distance between the absorption field and roof drains, basement sump pump drains, and any rainfall or surface water drainage systems. Increased flooding of the absorption field will inhibit the soil’s ability to naturally cleanse the wastewater, which will result in groundwater and/or surrounding surface water contamination. Conserve water to keep the septic system from being overloaded. Make careful to fix any dripping faucets or leaking toilets. Make use of low-flow plumbing fittings. When dealing with a clogged drain, avoid using caustic drain openers. Clogs should be unclogged instead with hot water or a drain snake. Avoid the use of septic tank additives, commercial septic tank cleaners, yeast, sugar, and other similar substances. Several of these items are not required, and some may even be damaging to your health. Commercial bathroom cleansers and laundry detergents should only be used in small amounts. Many individuals choose to clean their toilets, sinks, showers, and tubs using a gentle detergent or baking soda rather than harsh chemicals. If you have a trash disposal unit, check with the Humboldt County Division of Environmental Health (DEH) to ensure that your septic system is capable of handling the increased waste. Do not allow backwash from your water softener to enter your septic tank. Your septic system is not a garbage disposal system. Grease, disposable diapers, sanitary napkins, tampons, condoms, paper towels, plastics, cat litter, latex paint, pesticides, and other potentially dangerous substances should not be introduced into your system. Records should be kept of all system maintenance operations including repairs, pumping, inspections, permits granted, and other activities. Find out where your septic system is located in your home. Keep a sketch of it with your maintenance record in case you need to bring it in for servicing. Schedule an inspection and pumping of your septic system every three to five years by a professional inspector or contractor
- Only grass should be planted over and near your septic system. A blockage or damage to the absorption field may be caused by roots from surrounding plants or bushes. No portion of your septic system should be driven over or parked over. This might cause the dirt to contract and your system to be crushed.
In summary, understanding how your septic system works and following a few simple principles will help to ensure that your septic system is a safe and cost-effective method of treating and disposing of wastewater on your property.