Septic Systems: aerobic, above ground, alternative, and pumps

Septic system components can vary based on local conditions and age. Some older systems are as simple as one or more block cesspools and seepage pits.

Aerobic septic systems

Aerobic septic systems are used in situations where standard septic systems are not a viable option. In many cases, they are used to replace failing septic systems. Aerobic systems are similar to septic systems in that they both use natural processes to treat wastewater. But unlike septic (anaerobic) treatment, the aerobic treatment process requires oxygen. There are two types of bacteria, anaerobic and aerobic. Aerobic bacteria work much faster than anaerobic bacteria, which means they process septic tank waste more quickly. Aerobic treatment units use a mechanism to inject and circulate air inside the treatment tank, which accelerates or speeds up the treatment process. This mechanism requires electricity to operate. For this reason, aerobic systems cost more to operate and need more routine maintenance than most septic systems. However, when properly operated and maintained, aerobic systems can provide a high quality wastewater treatment alternative to septic systems. They can also be used in some cases by owners of wooded lots, who don't want to clear enough land to install a traditional septic tank and drainfield.

1. Pretreatment tank where influent enters.
2. Aeration chamber where oxygen is pumped into the waste water.
3. Clarifier chamber where the clear, odorless effluent rises.
4. Chlorinator where the clear effluent passes through for disinfection.
5. Holding tank for disinfected effluent ready for discharge.
6. Quiet, efficient aerator and pump.
7. Solid-state monitors and controls the system.
8. Discharge Pump

Above Ground Septic Tanks

In general, above-ground septic tanks (also called "holding tanks") are wastewater storage tanks which sit above the ground. Small, portable polyethylene tanks are made in 250 and 350 gallon sizes, and these are appropriate in some situations for temporary storage of sewage. Above-ground tanks may also be appropriate in water-front areas where below-ground storage and leaching is prohibited.

While holding tanks are occasionally used in seasonal cottages that don't have up-to-date plumbing options, permanent above-ground tanks are rarely used (at least in the United States). They suffer from a number of drawbacks:

• If they are not paired with a leaching field, they need to be emptied regularly: an often unpleasant and possibly expensive task.
• If the above-ground tank does work in conjunction with a leaching field, the sewage is typically transported into the tank via a pump (rather than gravity). This can cause the solids in the sewage to be chopped into smaller pieces, and to escape the tank along with the effluent. As the solids settle out of the effluent, they can block the pipes that lead to the leaching fields.
  Since above-ground tanks are exposed to the elements, they have a tendency to wear out more quickly than their cousins buried under several feet of earth.