Biomass production and nutrients removal by a new microalgae strain Desmodesmus sp. in anaerobic digestion wastewater

Anaerobic digestion wastewater (ADW), which contains large amount of nitrogen and phosphorus, particularly high concentration of ammonium, might lead to severely environmental pollution. A new unicellular green microalgae species from a wetland at the Olympic Forest Park, Beijing, China was screened based on its growth rates and nutrients removal capability under ADW. Results of 18s rDNA and ITS1 analysis indicated that this strain have a close relationship with Desmodesmus sp., named as EJ9-6. Desmodesmus sp. EJ9-6 could remove 100% NH4–N (68.691 mg/L), TP (4.565 mg/L) and PO4–P (4.053 mg/L), and 75.50% TN (84.236 mg/L) at 10.0% ADW, which the highest biomass production was 0.412 g/L after 14 d cultivation. Maximum nutrients removal was observed at 10.0% ADW with daily removal rates of TN, NH4–N, TP and PO4–P at 4.542, 5.284, 0.326 and 0.290 mg/L/d, respectively.