Bacteria reduction and nutrient removal in small wastewater treatment plants by an algal biofilm

Abstract

Attached algae settlement is frequently observed in effluents of wastewater treatment plants at locations with sufficient sunlight. For their growth they incorporate nutrients and the surface of the algal biofilm accumulates suspended solids from the clarified wastewater. During the photosynthesis process of algal biofilms oxygen is produced while dissolved carbon dioxide is consumed. This led to an increasing pH due to the change of the carbon dioxide equilibrium in water. The high pH causes precipitation of dissolved phosphates. Furthermore an extensive removal of faecal bacteria was observed in the presence of algae, which may be caused by the activity of algae. The experimental results indicate the high potential of these attached algae for polishing secondary effluent of wastewater treatment plants. Especially for small wastewater treatment plants a post connected stage for nutrient removal and bacteria reduction can be developed with the aid of an algal biofilm.

Enhancement of Penaeus monodon shrimp postlarvae growth and survival without water exchange using marine Bacillus pumilus and periphytic microalgae

“…Microalgae have also been reported to exhibit antibacterial activity [33]. The combination of microalgae and bacteria has been shown to overcome the virulence of V. campbellii and V. proteolyticus in gnotobiotic Artemia [34], and Schumacher et al [35] have shown that it is possible to reduce the level of nutrients and bacteria through the addition of an algal biofilm to a wastewater treatment system. Therefore, we suggest that the low counts of Vibrio in our experiment can be attributed to the B. pumilus and periphytic microalgae introduced into the tanks.…”

Scenario Analysis of Nutrient Removal from Municipal Wastewater by Microalgal Biofilms

“…A microalgal biofilm system can operate at short hydraulic retention times due to the ability of the biofilm to retain the biomass. It is also expected that, in contrast to suspended microalgal systems, little or no separation of microalgae and water is required before discharging the effluent [9,10]. Furthermore, no mixing is needed in the system, resulting in a lower energy requirement than for suspended systems.…”

Effect of light and temperature on biomass, photosynthesis and capsular polysaccharides in cultured phototrophic biofilms

“…Most of this research has focussed on freshwater biofilms because of their ecological importance and of the high potential biotechnological applications of these complex microbial associations, e.g. biomass production as energy source, wastewater treatment (Schumacher et al 2003) and bioremediation (Cohen 2002;Chaillan et al 2006). Phototrophic biofilms seem to be suitable candidates for tertiary wastewater treatment due to their high efficiency in removing inorganic nutrients, pollutants and xenobiotics (Hoffmann 1998;Guzzon et al 2008).…”