E-Week Spotlight: Leach Field Innovation


Anchorage’s National Engineer’s Week (E-Week) is an annual event to raise awareness of the work and contribution of our nation’s engineers. Events take place February 20-27, and include activities for adults and kids, as well as honors and awards recognizing local engineers. CRW wholeheartedly supports E-week, and loves that it gives us a venue to explain the cool things our engineers are doing! Read on to learn how CRW is helping bring new technology to Alaska.

CRW is assisting Geomatrix LLC, a Connecticut based residential and commercial wastewater treatment system manufacturer, with obtaining approvals to install their patented SoilAir Systems (SoilAir) in the Municipality of Anchorage. An innovative method to enhance and rejuvenate leach fields, SoilAir provides a new alternative to current methods of leach field treatment in Alaska.  Although approval is pending for use in Anchorage, SoilAir may be allowed for use in other areas of the State with an engineer’s approval.

Leach fields, the final step in typical onsite wastewater treatment, provide a media for microorganisms to process the organic matter left in wastewater after it leaves the septic tank, but before it flows into the surrounding groundwater.  Two broad categories of microorganisms exist in the leach field: aerobic and anaerobic.  Aerobic microorganisms process the organic matter in wastewater very well, but require an oxygen rich environment to flourish.  When oxygen is not readily available, anaerobic microorganisms, which are less effective at processing the organic matter in the wastewater and produce slimy byproducts, become dominant.  Over time, the undigested organic matter and slimy byproducts build up, allowing less and less wastewater to flow through, leading to the leach field’s eventual failure.  Until now, failure of an Alaskan leach field meant that a new one would need to be constructed, which can be costly and can negatively affect landscaping and other property improvements.

The SoilAir System in action  

Geomatrix LLC’s SoilAir solution may be just the ticket for sites where the soils are marginal or where there is not room to build a new drainfield, such as on the Anchorage Hillside. Geomatrix developed and patented SoilAir to dose leach fields with wastewater followed by a charge of air.  This introduces a process of nutrient inflow followed by oxygen transfer, optimizing the environment for aerobic microorganisms to flourish and maximizing the level of treatment in the leach field. SoilAir can be used to extend the life of new leach fields and rejuvenate existing failed or failing leach fields.  This translates into significant cost savings for homeowners who are able to avoid constructing present or future replacement leach fields.

The simple installation uses an air blower connected to a float and check valve in the septic tank.  The air blower and associated controls are installed in a small, unobtrusive box next to the building being served.  When wastewater in the septic tank reaches a certain level, the controls trigger the system to dose wastewater followed by air to the leach field.  Sensors can be installed to monitor septic system operation to determine aeration frequency.  The system can also be set-up to be monitored via remote telemetry through a non-dedicated telephone line. 

More than 2,000 SoilAir Systems are currently in operation, enhancing leach field performance in the Lower 48 and Canada in a variety of climates.  CRW is excited to assist Geomatrix LLC in bringing this technology to Alaska and looks forward to the first installations in Alaska in 2016.  For more information on SoilAir Systems, please visit www.soilair.com.  If you are interested in having a SoilAir System installed at your residential or commercial property, please contact Matt Edge, PE at medge@crweng.com.