Technical Report No. 102
NITROGEN REMOVAL FROM SECONDARY EFFLUENT BY A LABORATORY SOIL COLUMN
Gordon L. Dugan, Paul C. Ekern, and Roy T. Tsutsui
August 1976
ABSTRACT
The objective of the project was the investigation of the percolate rate and the disposition of nitrogen from a laboratory soil column when chlorinated secondary sewage effluent was applied under both continuous and intermittent loading. A 1.7-m (5.5-in.) diameter column was packed to a depth of 1.5 m (5 ft) with a well-aggregated Oxisol soil (Lahaina series). A constant head was maintained by a modified Mariotte bottle during the application of effluent. Percolate was sampled through ports at 7 depths as well as from a bottom drain.
When effluent was continuously ponded on the surface: (1) percolate rate decreased with time, (2) ammonium ions were adsorbed, (3) nitrification was suppressed, (4) denitrification occurred, and (5) the denitrification biological community required more than 2 days to develop.
When effluent application was stopped after 2 days and aerobic conditions developed, nitrification was very active within 5 days.
The solute breakthrough curve appeared well in advance of 1 pore volume and was highly skewed with an extended tail.