Study on removal efficiency of nitrogen and phosphorus by freshwater benthic algae

This paper is aimed to discuss the removal ability on nitrogen and phosphorus from synthetic wastewater by freshwater benthic algae. A simulated test was conducted using the tested benthic algae collected from a discharge way of a paper mill wastewater in Wuhan. The results showed that the community structure of the benthic algae was mainly composed of filamentous green algal species with the most abundant alga of Stigeoclonium sp., which could grow well and showed a relatively high ability to removal nitrogen (N) and phosphorus (P) from synthetic wastewater. During a 5-days treatment, the concentrations of total nitrogen (TN) and total phosphorus (TP) in synthetic wastewater were changed from 36.97 +/- 0.26 mg.L-1 and 2.88 +/- 0.02 mg.L-1 to 1.44 +/- 0.09 mg.L-1 and 0.07 +/- 0.01 mg.L-1, respectively. The removal rates on TP, TN, ammonia-nitrogen (NH4-N) and nitric-nitrogen (NO3-N) were up to 96%, 98%, 98% and 97%, respectively. Simultaneity, algal biomass could be harvested to 14.36 +/- 0.72 g. The contents of total Kelvin-nitrogen (TKN) and TP of harvested algal biomass were 5.75 +/- 0.20% and 1.56 +/- 0.22%. It is implicated that freshwater benthic algal treatment system may have potential use in controlling lake eutrophication and be served as a means to restore lake ecosystem.