SEPTIC TANK SYSTEMS

What is A Septic Tank System?

A septic tank system consists of a large, watertight tank that receives wastewater from the home plumbing system. The tank is followed by an underground drainfield consisting of a network of perforated pipe or chambers for distributing partially treated water from the septic tank to the soil for final treatment and disposal.

How Does It Work?

Septic tanks contain bacteria that grow best in oxygen-poor conditions. These bacteria carry out a portion of the treatment process by converting most solids into liquids and gases. Bacteria that require oxygen thrive in the drainfield and complete the treatment process begun in the septic tank. If the septic tank is working well, the wastewater which flows out of the tank is relatively clear, although it still has an odor and may carry disease organisms. It should flow only into the drainfield. NEVER ONTO THE GROUND SURFACE OR INTO FLORIDA WATERS!!!

Operation and Maintenance After the septic tank system is placed in service, proper operation and maintenance of the system will ensure continued efficient service and prevent sudden replacement expenses. The septic tank and drainfield are designed and installed to handle a maximum calculated daily sewage flow. Consistently exceeding the design flow will eventually overload the system and cause failure. The tank may receive new solids faster than it can treat them and the drainfield may become saturated from excessive water use. Various products are on the market which are said to start, accelerate or improve the action in the septic tank. Since all necessary bacteria are already present in the sewage entering the system, such products are not recommended.

Cross section of a Septic tank

Maintenance of a septic tank will depend largely on the daily sewage flow and individual household wastewater characteristics. With ordinary use and care, a septic tank should not require pumping out more than once every three to five years. It should, however, be inspected to determine the depth of accumulated sludge and grease. Waste from a kitchen garbage disposal units puts an extra load on a septic tank system. If a disposal is used, the capacity of the tank should be increased to handle the increased solid wastes. The tank may also require more frequent pumping to remove accumulated solid waste buildup. Failure to pump out a septic tank system when indicated will result in solids or greases overflowing into the drainfield, which in turn may become clogged and stop functioning. In this event, not only will the tank have to be pumped out, but the drainfield may also have to be replaced. Septic tanks can be cleaned by septic tank cleaning firms permitted by the county health department. This type of work should be done only by experienced professionals who will pump the entire contents of the tank into a tank truck and dispose of the contents in an approved, sanitary manner.

Location

Contaminants can travel long distances in some soils. Therefore, drinking water wells should be located at least 75 feet from any part of a septic tank system. With certain exceptions, septic tanks and drainfields must be located at least 75 feet away from the high water line of ponds, rivers and lakes. Also, the drainfield should be located so that it will not be saturated by surface water drainage or runoff from roof gutters.

Preventing Failures

Septic tank systems fail when the drainfield does not dispose of sewage as rapidly as it is being added to the system. Thus, improvements that reduce the amount of incoming water or improve the quality of wastewater passing through the system will increase the system's longevity. Other important considerations include the following:

• A drainfield can be damaged by compaction due to vehicular traffic and can be blocked by excessive shrubbery or tree root growth. The drainfield should be unobstructed and seeded with grass. Grass and sunlight aid evaporation.
• Washing machines are responsible for large volumes of water entering the septic tank. The surge of wash water can create turbulence in the tank which increases the amount of solids flushed into the drainfield. Space washings throughout the week rather than doing many loads at a time, or, install a separate system for washing machine water.
• Cooking oils and grease are trouble makers. The type of bacteria found in septic tanks and drainfields do not survive or function well in solidified grease. Grease and cooking fats should never be washed down the sink drain. Save grease in jars or cans for disposal in the garbage.

Do's

• Know the location and capacity of your septic tank system. If you have a copy of your original permit, keep it available for future reference.
• Have a licensed contractor inspect the tank at least every three years.
• Have tank pumped when the combined depth of the sludge and scum equals 1/3 of the tank liquid volume.
• Install the system so that rainfall and surface water will flow away from the drainfield. · Grow grass above the system.
• Install water conservation fixtures or devices to reduce the total volume of water entering the system.
• Keep plumbing fixtures such as toilets and faucets in good repair to prevent leakage and wasting of water
• Keep copies of maintenance receipts. Keep a sketch of the location of your tank and drainfield.

Don'ts

• Never flush paper towels, newspapers, wrapping paper, rags or sticks into the system.
• Never allow large, irregular, intermittent or constant volumes of clear water into the system, as with a leaking toilet or faucet.
• Never over-use ordinary household cleaning chemicals that will be flushed into the system.
• Never pour out or empty hobby or home industry chemicals into the system.
• Never allow grease or other bulky waste to enter the system.
• Never flush toxic materials such as pesticides into the system.
• Never plant trees or shrubbery in the drainfield.
• Never allow vehicles (cars, trucks, etc.) to drive across or park on the drainfield. (Protect it from being crushed.)
• Never waste water.
• Never use chemical solvents to clean plumbing lines or a septic tank system.