Septic Fields

[Anonymous]

I am planning to build a cabin over the next year or so. I would like information on how to build a septic field, or if there are any other options? Greg

[John Aldrich1Participant]

Greg, I recommend that you check with the local regulatory agency responsible for issuing permits for on-site sewage treatment systems in your area. There are, no doubt, minimum design standards with which you must comply. There are options available for the treatment of domestic sewage other than the conventional septic tank/soil absorption systems in common use.

The design of the system that you finally select will depend upon the site constraints on your property, the volume of sewage to be treated, the climate in your area, the approval status of alternative sewage treatment technologies in your jurisdiction, the presence or lack thereof of suitable soil, and many other factors that you have not revealed.

If the use of the cabin is very limited, it may be that a holding tank would be the most economic approach in handling the sewage disposal requirements of your cabin. If the cost of a soil absorption system is very high, and the sewage volume to be treated is low, then hauling the sewage to a central sewage treatment facility may be the most economical approach. Do an economic analysis of the front end capital investment for both systems, and the long term cost of hauling the sewage. This typically cost from $150 to $200 for 1000 gallons of sewage.

If a septic tank/soil absorption system is selected, then I recommend that risers to the ground surface be installed on both the inlet, and the outlet ends of the tank. Install a septic tank effluent filter in the outlet tee of the tank. There are many quality filters on the market, and the maintenance of the filter is an easy task.

It is my belief that leach fields should be designed so that half of the leach field is receiving “filtered” septic tank effluent while the other half is in the resting mode. The Advanced Drainage Systems, SB*2 gravelless leach fields that I design and install consist of a 4 inch plug valve, 2 separate leach fields (each containing 50% of the required leach field capacity), and monitoring/ventilation ports on each end of each field. The in-use field ports are fitted with threaded 4 inch plugs so that sewer gas odors are confined, and the resting field ports are fitted with 4 inch drain grates so that atmospheric oxygen has a pathway down to the clogging mat. The leach field ports are covered with 6 inch irrigation valve boxes which are set at the final grade elevation. The plugs and the drain grates are exchanged when the diversion valve is turned. The soil around the leach field never “dries out”, but rather becomes “unsaturated.” Atmospheric air replaces the effluent as it slowly percolates through the clogging mat. The oxygen in that air oxidizes the Ferrous sulfide, that black slimy crap in the clogging mat, and tranforms the environment into an aerobic condition. Aerobic microbes then move in, and consume the dead bodies of their anaerobic cousins, and rapidly consume any organic matter that has escaped the septic tank. I recommend to my clients that the effluent flow be alternated annually.

I have chosen the 4th of July, “SEWAGE INDEPENDENCE DAY”, as the day to perform the annual maintenance duties required for the septic system. This is a date that most people easily remember, and they can “celebrate their independence of the sewer grid.” I prepare an operation manual titled “SEWERS CAN BE BEAUTIFUL”, which contains photographs of the installation, a description of the system design, instructions for maintenance, an as-built plan, the ISDS PERMIT, and a maintenance log which is a record of the maintenance performed on the system. This document becomes a valuable sales tool when the property is offered for sale. If you have other questions regarding these issues, send me an e-mail message with more details of your specific situation. JWA

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