Our 24’x36′ greenhouse is set up with locations for up to nine separate small-scale soil column experiments. At present we are utilizing six locations, with plans to expand to the full nine. There is also space available for a number of other small-scale experiments in the greenhouse.
The barrels are fed septic tank effluent (STE) from above via the white dosing barrels. A solenoid valve opens, releasing the STE into the distribution media in the column. Each column is underdrained, with the effluent running through a small sampling sump before collection and final disposal.
Full-Profile Columns (Three)
Three columns are set up to test the variation in nitrification (conversion of ammonia to nitrate) across different soil loading rates:
- .74 gallons/square foot/day (Title 5 loading rate for sandy soils)
- 1.11 gallons/square foot/day
- 1.48 gallons/square foot/day
Each column contains 24″ of “Title 5” (ASTM C-33) sand. Geomatrix, LLC’s Geomat is used as the distribution system with about 6 inches of covering soil over top.
Three additional columns are set up with 16″ of “Title 5” (ASTM C-33) sand. Geomatrix, LLC’s Geomat is used as the distribution system with two inches of sand as cover. These columns are currently being re-configured to look at the effect of cleaning and personal hygiene products on nitrification.