A septic tank system serves as an on-site wastewater treatment system in places where public sewers are not available. One-third of all Florida homes, about 1.6 million households, use septic tanks.
Septic Tank Systems
- The septic tank system is an underground system of pipes and tanks designed to treat bathroom, kitchen and laundry wastewater through naturally occurring bacteria and microorganisms.
- In older homes, a septic system may be a pipe leading from the house to a cesspool.
- In newer homes, a septic system usually is made of a series of pipes connecting a septic tank, distribution box and a leach, or drainfield.
Septic Tank System Importance
- Processing raw sewage through a septic system is important because it protects the groundwater and the environment from contamination.
- Microorganisms and insects living within the drain field assist in decontamination of waste materials by consuming leftover waste particles containing such harmful germs and viruses as typhoid, gastroenteritis and viral hepatitis.
- To ensure the proper functioning of a septic system, homeowners must take precautions to prevent system failures.
Septic Tank Types
There are many different types of septic systems. Some of them include pressure distribution, sand filter, mound, and gravity.
Gravity Septic Tank Systems
- The majority of septic systems in the United States are of the conventional gravity type.
- Gravity septic tanks do not include a septic effluent pump. They simply rely on gravity to carry wastewater from the home’s sinks, showers and toilets into an onsite sewage treatment system.
- These type of septic system use gravity to drain wastewater from the tank into a series of trenches.
- Because this system works using gravity, the drainage field must be below the level of the septic tank.
- The bottom of the trenches must be three or four feet above the water table.
- Soil above the water table is used to treat the wastewater before it returns to the environment.
- Gravity systems typically consist of a buried tank and drainfield laid out in beds of sand and gravel.
Pressure Distribution Septic Tank System
- A septic effluent pump is added to a home sewage system when an area is not adequate to allow for the gravity flow to work properly.
- It pumps effluent, or wastewater, into the drainfield from a second underground tank.
- The pump tank holds wastewater until a certain point before it releases it into the drainage field.
- Pressure distribution systems are normally used when there is not enough soil depth to accommodate gravity-based systems.
Sand Filter Septic Tank Systems
- Sand filter systems are one of the most common types of septic systems.
- This system uses sand between the pump tank and the drainage field.
- The sand is used to treat the wastewater before it enters the field. These types of septic systems are used when there is very shallow soil.
- Treating the wastewater with sand makes up for the lack of soil that would normally be used to treat the waste.
Mound Septic Tank System
- This system is also used when the soil isn't deep enough for a traditional system.
- These types of septic systems have a sand-filled mound raised over the natural soil above a drainage field.
- The wastewater is treated as it travels through the sand and into the natural soil.
- One of the more unconventional types of septic systems is the aerobic design.
- The system is equipped with a watertight tank that has an aeration chamber. Waste is broken down by bacteria in the aeration chamber.
- These systems are capable of producing cleaner wastewater, so they are commonly used in sensitive environments.
Typical Operation of Gravity Septic Tank Systems
- When sewage exits a home and enters a septic system, it first enters a septic tank.
- The solid waste--excrement, toilet paper and food debris--settles to the bottom of the tank and becomes sludge.
- Grease, fats and oils float to the top, becoming scum.
- Effluent is the liquid waste that is situated between the sludge and the scum, and it flows from the septic tank out into the drainfield when more waste enters the tank.
Septic Tank Effluent Pump
- In some areas, there is insufficient land or the groundwater is too near the surface to accommodate a traditional gravity septic system.
- Sometimes the land where the septic system is located is higher than the land the home sits on.
- In these cases, a septic effluent pump is needed to move the wastewater into the treatment area, insuring the proper disposal and detoxification of liquid waste.
- The septic effluent pump is located in a pumping chamber connected to the septic tank.
- This chamber includes the pump; water flow controls, or floats; and an alarm.
- The pump moves wastewater from the pumping chamber into drainfield or a mound system to be treated. Pumps are electric and on a separate circuit from the alarm.
Septic Tank System High Water Alarm
- If the pump malfunctions, the alarm sounds and a light flashes.
Inspect the electrical parts of the pump and control floats annually for corrosion and proper functioning. Test the alarm system regularly.
- Repair or replace any damaged parts immediately
Septic Tank System Pump Screen
- An effluent pump screen should be Installed and monitored to filter out any solids that might flow into the pumping chamber.
Septic Tank System Precautions
- A septic effluent pump works best when the sludge and scum in the first tank is regularly extracted to allow for proper effluent flow into the pumping chamber.
- To cut down on sludge and scum, use your garbage disposal sparingly or disconnect it. Never flush trash down your toilet.
- Dispose of kitchen grease in the trash.
- Don't use bath oils and other grease-based products, which can clog the septic tank outflow pipes.
- Make sure there is plenty of room for the septic effluent pump to move wastewater through the system efficiently.
Identifying Septic Tank System Failure
- Stop, look and smell!
- Check for pooling of water or muddy soil around your septic tank, cesspool or leach field.
- Check for odors of sewage or a "rotten egg" smell around your septic system or even in your basement.
- Notice if your sink or toilet backs up when you flush or do laundry.
- Septic systems also fail when the water they contain comes in contact with groundwater. This type of failure is not so easy to detect but can still result in the pollution of nearby streams or other bodies of water.
- Consult local septic system professionals and water quality representatives if any problems and/or questions occur with the septic system.
Maintaining A Septic Tank System
- Septic systems can function very well with minimal care if the system is properly cared for and utilized.
- Most septic tanks will only require a pumping out and inspection by a professional every three years if they are utilized properly.
- Most modern septic systems have a life span of nearly 25 years if they are maintained and cared for properly.
- Pump out and have the septic tank system inspected by a professional every three years. Failure to pump out the septic tank is the most common cause of septic system failure. If the septic tank fills up with an excess of solids, the wastewater will not have enough time to settle in the tank. These excess solids will then pass on to the drain field where they will clog the drain lines and soil.
- Know the location of the septic system and keep a record of all of its inspections, pumping, repairs and contract or engineering work for future reference.
- Ensure the septic system is installed so that rainfall and surface water flow away from you entire septic system. Excess water can come into the system from storms and groundwater, causing a failure to the system.
- Grow grass or small plants above the septic system to hold the drain/leach field in place. Xeriscaping, or water conservation through creative landscaping, is a great way to control excess runoff.
- Install water conserving devices to reduce the volume of water running into the septic system.
- Do not put grease or non-biodegradable materials down your sink or toilet. Grease can thicken and clog the pipes. Store cooking oils, fats, and grease in a can for disposal in the garbage.
- Do not flush paint thinners, polyurethane, anti-freeze, pesticides, some dyes, disinfectant, water softeners and other strong chemicals, which can cause major upsets in the stomach of the septic tank by killing the biological part of your septic system and polluting the groundwater. Small amounts of standard household cleaners, drain cleansers, detergent, etc., will be diluted in the tank and will cause no damage to the system.
- Do not flush indigestible materials such as diapers, cigarette filters, feminine napkins, cat litter, plastic, rubber, nylon or even hair, into the tank from any source, including sinks, toilets or washing machines. These products do not decompose in the septic system and will cause frequent and costly repairs for the homeowner and harm to the environment. Do not use a garbage grinder or disposal which feeds into the septic tank system. If you do have one in the house, severely limit its use. Adding food wastes or other solids reduces your system's capacity and increases the need to pump the septic tank or cesspool.
- Do not plant trees within 30 feet of your system or park/drive over any part of the system. The pipes and drain/leach field will clog, rendering the system inoperable and ineffective.
- Do not perform all machine washing in one day. One laundry load can use up to 60 gallons of water and could overwhelm the whole septic system with excess wastewater. Consult your septic tank professional to determine the gallon capacity and number of loads per day that can go into the system.
- Do not use chemical solvents to clean the plumbing or septic tank system. "Miracle" chemicals will kill microorganisms that consume harmful wastes in the septic tank system. These products can also cause groundwater contamination.