The role of plants in ecologically engineered wastewater treatment systems

A Solar Aquatic System(TM) (SAS) septage treatment facility with aquaculture and constructed marsh components operated as a pilot facility from 1989 through 1992. The nitrogen loadings to the aquaculture subsystem were 15.6 gN m(-2) day(-1). Sixty-eight percent of the nitrogen was removed, with 4% of the removal by vegetative uptake. The nitrogen loading to the marsh subsystem was 5.23 gN m(-2) day(-1). Thirty-eight percent of the nitrogen was removed, with 1% of the removal by vegetative uptake. Although responsible for only a fraction of the nitrogen removal, the productivity of the plants in the SAS was comparable to that of plants in less heavily loaded wetland systems reported in the literature. The nitrogen content of plants in the SAS was higher than of plants in a heavily loaded system. Comparisons are made among three wetland systems with loadings ranging from 0.44 to 1.83 gN m(-2) day(-1) where up to 30% of the nitrogen was removed by the plants.