SECRETS OF THE SEPTIC SYSTEM

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The success of the system should be no mystery.

By Richard Freudenberser

THE HOME SEPTIC SYSTEM

The septic tank is an essential part of the system. The two-chamber design shown here is popular because it’s uncomplicated and reasonably effective—but flooding or overloading the tank can still send undigested material into the drain lines, clogging the absorption field. To eliminate that problem, the latest tank designs take advantage of deep holding chambers and internal convolutions to encourage solids to settle out from the flow.

ALMOST 60 MILLION PEOPLE IN America practice inexpensive and effective home-scale recycling every time they run water. Individual, on-site sewage disposal systems—"the septic" to some country folks—do a commendable job of treating domestic waste through a natural biological process that eventually returns most spent water safely to its source. However, septic systems aren't perfect. Because of them, we tend to use too much water—perhaps 40% too much. Moreover, as long as the liquid is flowing in the right direction—out—we assume the plan is working, when in fact it may be broadcasting bacteria and discarded household chemicals.

The Dirty Truth

The boast of a homeowner who claims 20 years of trouble-free septic service is, sad to say, a shallow one. A properly designed septic system is supposed to receive occasional maintenance—usually nothing more than a cleaning every few years to remove accumulated insolubles. An untended unit can easily be overtaxed without a sign, quietly suffocating itself until it reaches a point at which it becomes less expensive to replace the system than to try to save it.

Then again, some systems are improperly designed or installed and cause their owners to face upkeep and expense beyond the norm. Frequent pumping, costly chemical treatments and mechanical handling systems shouldn't be necessary with a good installation.

Abuse of a system, however, will quickly lead to problems. No matter how conveniently paint thinners, cigarettes, hair and harsh household cleaners go down the drain, they have no place there. Foreign—and especially nonorganic—material may never break down and can contaminate both the system and the local water supply.

Think of the septic system as a continuation of your household drain plumbing. Every water-bearing fixture in your home is connected by drainpipe to one main line that carries the highly diluted waste material to an air-and watertight septic tank buried a foot or so beneath the soil and at least 10 feet from the house.

The tank can be constructed of precast concrete, fiberglass, steel and even stone or sealed brick. Average capacity is 750 gallons, though smaller tanks do exist. For large homes or households with more than five people or two baths, 1,000-and 1,500-gallon tanks are available.

By design, the tank has two functions. One is to serve as a settling chamber for heavy solids and as a trap for the floating grease film that rises to the liquid's surface. The other is to provide ideal conditions for the digestion and ultimate breakdown of organic waste material.
Not surprisingly, the two are dependent upon one another. In most modern tanks, internal baffles slow the flow of incoming material, allowing solids to settle. The anaerobic (meaning there's no available oxygen) environment within the chamber encourages specialized bacteria which feed upon the cellulose, starches and so forth contained in waste matter. These living organisms are so small that perhaps 25 million might fit in a square inch of area.

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