Septic Tanks – The Guide

What is a Septic Tank:

A septic tank an essential part of the septic system.  A septic tank is for small scale sewage treatment; they are common in areas that are not connected to the main sewage line.  They are mainly controlled and operated by local governments, though they are sometimes privately owned and maintained as well.  Close to 25 percent of the North American population relies on septic tanks.  In North America septic tanks can be used in cities, small towns, and rural areas.  However in other areas of the world, such as Europe, septic tanks are not suitable in cities, so they are primarily used in rural areas.

side view of septic tank diagram

The Septic Tank is Step 1 of the process. After liquid leaves the septic tank it goes to the Drain Field.

Septic Tank Emptying:
Solid waste from the septic tank must eventually be liquified by the bacteria in the tank, otherwise the system will discharge these solid materials into the drainage system.  This would have negative effects on the environment, and may clog piping systems, which may result in expensive repairs.  When a septic tank is emptied the solid waste is removed by a vacuum truck. The size and amount of waste in a septic system are the determining factors in how often the tank must be emptied.  A properly maintained septic tank will not require emptying, as bacteria eats the solid waste, rendering it in liquid form, which is then safely and efficiently dispersed through the drainage area into the soil.

cross view of a drain field for a septic system

The Drain Field is how the liquid waste is dispersed safely into the soil. This is the Second and Final Step of the process.

Septic Tank Maintenance:
Like all sewage systems, septic tanks require maintenance.   The maintenance is usually the responsibility of the resident or property owner.  However certain actions may result in an increased need for maintenance.  Disposing of cooking grease or other types of oil and grease may cause blockage throughout the system and may be difficult and costly to repair.  Also the disposal of cigarette butts, cotton swabs, and sanitary napkins may also result in a clogged system.  Certain chemicals may also cause the septic system to need repairs or require more effort for septic tank maintenance.  Some chemicals or pesticides may kill important bacteria needed in order for the septic system to operate properly.  Other factors may include tree roots or branches rupturing or blocking the system, excessive water emptying the system, excessive rainfall, and the development of biofilms that form after long periods of time.

Septic tank additives:
Septic tank additives can be used in order to help reduce septic tank built up and reduce odors.   Primarily, if a septic tank is failing, it is because of a lack of bacteria in the tank.  There are, luckily, bacterial additives that can be administered to the tank, which can restore bacterial levels, and therefore, the functionality of the septic tank.  There are varying types of bacteria that can be added to your septic system.   In general, if proper bacterial levels are constant in a septic tank, the need for pumping and maintenance can be avoided.  As a result, it is common to administer a bacterial additive monthly, as a preventative maintenance procedure.

Environmental concerns:
A septic tank that is properly maintained poses no real environmental risks or concerns.  However when septic tanks are not properly maintained, the risk of groundwater pollution and surface water pollution can become an issue.

Works Cited
“Septic Systems.” National Environmental Services Center. N.p., n.d. Web. 9 March 2016. <>.
Tilley, Elizabeth. Compendium of Sanitation Systems and Technologies. Dübendorf: Swiss Federal Institute of Aquatic Science and Technology (Eawag), 2014. Print.