Alternatives appearing in septic systems

In the past 15 years or so, sand filters, sand mounds, timers, pressure pumps, and other comparatively complex systems have made their presence felt in the previously mechanically simple on-site sewage-disposal-system arena.

Increasing regulatory pressures have driven up the costs and complexity dramatically.

Technology has, of course, added to the older construction techniques as new systems have arrived and been approved by many county and state health departments.

An example of one of the newer technologies is a "Glendon Bio-Filter" (named after the two inventors — Glen and Don). It's a proprietary system that releases extremely clean effluent.

Although it requires scheduled professional monitoring, it can be installed on a piece of land that in the past may have been considered unbuildable due to poor quality or shallow undisturbed soils.

This system, while not cheap, and visible above the ground, can also be used on lots that were too small for conventional systems in the past.

A "Whitewater" system uses an ultraviolet light and aerobic motion to break down many of the contaminants in the effluent before it enters the pump tank or drain field.

Dean Blacketer, owner of HD Quality Septic Design in Woodinville, says a Whitewater system can serve as a replacement, or as an initial construction option, for those requiring sand filters due to soil type.

Sand filters are generally physically quite large and tend to be prone to longevity problems (particularly with the use of a garbage disposal or poor quality sand). Techniques and treatments such as air infiltration are being developed and tested to mitigate sand-filter problems.

Being a septic designer, Blacketer and soil engineers daily must decide (among other things) if a soil is a loamy sand or a sandy loam; a clay-like silt or a silty clay; a clay-like sand or a sandy clay; sandy gravel or a gravelly sand; and also a type I, II, III, on up through a type VI soil. Yikes! No, I did not make any of that up.

"Infiltrator" type systems have been used quite a bit in the drain field repair business of late.

Infiltrators are seen on new installations as well, and that percentage will probably increase because they can reduce costs; no imported gravel is needed in the ditch, and they may be shorter in total length than a conventional drain field.

Take a 36-inch diameter pipe, cut it lengthwise, place it over a ditch, backfill over the top and force the effluent spray upward into the arc of the pipe.

What you just did, in essence, is build yourself an infiltrator. The effluent spraying upward, then dropping downward, over the entire width of the pipe helps distribute it evenly throughout the ditch.

This distribution pattern aerates the effluent and is more efficient than those cases where the effluent is forced downward directly into the center of the ditch, and laterally only at perforations — which is what happens in a conventional pressure-system drain field.

Darrell Hay answers readers' questions. Call 206-464-8514 to record your question. Or e-mail dhay@seattletimes.com. Sorry, no personal replies.