The role of algal components in phosphorus-removal from sewage effluent in an experimental aquatic vegetation site at Arborg, Manitoba

Abstract

The effectiveness of two algal components, the epiphyton and phytoplankton, in removing phosphorus from sewage effluent passing sequentially through a series of artificial ponds, was studied. Artificial substrates of clear cellulose acetate were provided for colonization by epiphytes, and weekly samples of scraped algal material, as well as suspended algal material were analyzed for particulate phosphorus, particulate organic carbon, and species composition and number. Two of the artificial ponds were planted with aquatic macrophytes, and one of these was found to be more effective than a control in stripping phosphorus from the effluent, while the other was not. The epiphytic component was judged to be not very significant in the amount of phosphorus removed, averaging approximately 1%, while the suspended algae removed mean amounts varying from 0.64-33.81% in different ponds over the season. However, the total epiphyton in these ponds was small, owing to the limited number of planted macrophytes. The amount of epiphytic carbon produced in a weekly interval varied from 0-620 grams. The greatest number of epiphytic and suspended algae belonged to the Cyanophyta, with fewer Chrysophta and Chlorophyta.