Wastewater leaves the house and enters the septic tank. The septic tank performs two functions. First it acts as a holding tank and allows the solids to settle out. The heavier solids sink to the bottom forming the sludge layer. The lighter solids, fats, oils, grease, etc… rise to the surface and form the scum layer. The relatively clear layer in the middle is called effluent. Second, naturally occurring anaerobic bacteria begin breaking down the solids in size and destroying the pathogens. This is a standard septic system. The treatment process starts in the septic tank and is completed in and around the drainfield.
After the treatment process is started in the septic tank, the effluent enters the soil treatment phase of the process (baffles and/or filters prevent the larger floating solids from exiting the septic tank and entering the drainfield). The soil treatment system, more commonly called the drainfield, is comprised of distribution pipes or chambers laid in a trench or bed and covered with topsoil. Some of the older systems have rock in them.
As the effluent enters the drainfield, it percolates through the drainfield bed where a large portion of the pathogens are destroyed. Pockets of oxygen in the pipes, chambers (or rock) allow the more efficient aerobic bacteria to exist. When the effluent exits the drainfield, the natural soil beneath completes the treatment process. By the time the effluent has traveled 2-3 feet through the soil, all the remaining pathogens have been destroyed and the water is drinking quality. The cleaning process continues as the water migrates through the soil. Phosphorus and nitrogen are utilized by the vegetative life covering the drainfield and chemically changed in the soil. A large portion of the moisture is returned to the atmosphere through evaporation (evapotranspiration).n and around the drainfield.
Failures can be avoided by learning how a septic system functions, how to properly use it, and what steps you can take to protect it. The basics of protecting a system are really quite simple, once you realize that they work on a bacterial process. and bacteria can’t break down plastic, polyester or nylon….too many harsh cleaning solutions will kill off the good bacteria. Regularly pumping your septic tank for maintenance is the key! Also a septic system can only handle a certain amount of water per day. If you put more water down the drain than it can handle, you will overload the system.
Install water-saving appliances, devices, and practice water-saving techniques. Repair plumbing leaks. Leaking toilet valves are a major culprit of hydraulic overload, putting hundreds of gallons of water through the system every day.
Install filters for the washing machines to remove the fine solids from the discharge, and do not use or minimize the use of garbage disposals. Installing septic tank filters also helps to prevent the solids from entering the drainfield.
Conserve chemical usage. Automatic toilet bowl cleaners can be very hard on a system because they kill the bad bacteria in the toilet, but the killing process continues throughout the system. This also holds true for laundry soaps and antibiotics!
Water use should be spread out. Do one or two loads of laundry per day rather than making 1 day laundry day!
Exit baffles should be replaced with effluent filters. These cleanable filters prevent the larger solids from reaching the drainfield.
Have the tank pumped and inspected every one to three years. Tanks should be pumped and inspected through the manhole cover, not the main line clean out pipe. This is proper maintenance, and is the same principle as giving your car an oil change every so many miles….to prevent the engine from going bad too soon. Pumping your tank regularly will help to extend the life of your drainfield.
These devices can put several hundred gallons of water down the drain every week that is not contaminated and does not need to go through the treatment process. Also if you have the salt type water softener, the sodium can harm your drainfield by causing the soils to seal rather than stay porous and breathable. Up-grade your softener with a newer efficient model that uses less water and regenerates on demand (when you use X number of gallons of water) instead of a timer system that regenerates whether you use water or not. You can also install a mini septic system for your softener.