Nitrogen and phosphorus removal by high latitude mat-forming cyanobacteria for potential use in tertiary wastewater treatment

摘要: As part of a program to develop biological wastewatertreatment systems for cold climate areas four strainsof filamentous, mat-forming cyanobacteria isolatedfrom Arctic and Antarctic environments were evaluatedfor their nutrient stripping growth capabilities. A tropical strain, Phormidium bohneri, known forits excellent performance in wastewater treatment, wasused as comparison. Experiments done inartificial media under controlled batch cultureconditions avoid interactions with indigenousmicroorganisms such bacteria protozoa. Theculture medium simulated real effluents containinghigh concentrations nitrate phosphate.Temperatures (5, 15 25°C) irradiances(80, 210, 350, 640 1470 µmol photon m-2s-1) wereselected according situations encountered avariety field conditions. For all irradiancelevels, was satisfactory at 25 °C,but limited 5 °C. At °C nitrogen removal rate (3.5and 4.0 mg N L-1d-1) obtained forone polar strain (Phormidium tenue) thecontrol P. bohneri. °C, the bestnitrogen (3.5 L-1d-1)was measured bohneri while best ratefor strains around 2.3 NL-1d-1. phosphorusremoval 0.6 P L-1d-1 wasobtained tenue Oscillatoria O-210. Nitrogen(NO3 -) phosphorus (PO4 3-)uptake rates increased function irradianceover range 80 350 μmolphoton m-2s-1. Our results indicate thattertiary treatment lowtemperatures (5 °C) cannot be anticipated withthe tested, because they arepsychrotrophic rather than psychrophilic thus growtoo slowly conditions extreme cold. However, it appears that these would beuseful moderately cooltemperatures (c. °C), which are commonduring spring fall northern climates.