The effects of refractory pollutants in swine wastewater on the growth of <i>Scenedesmus</i> sp. with biofilm attached culture

Abstract

Microalgae have been widely used for treatment of swine wastewater. However, the research on combined treatment of refractory pollutants ammonia nitrogen, Cu (II) and antibiotics from swine wastewater was still scattered. This study, the growth and removal efficiency of NH₄Cl, CuSO₄, tetracycline, norfloxacin and sulfadimidine with selected <i>Scenedsmus</i> sp. was investigated by biofilm attached culture. The results showed that low concentration of ammonia nitrogen had little effect on algae growth. The highest biomass productivity was 6.2 g/(m²d) at the concentration of NH₄Cl of 50.0 mg/L, which was similar to that of a standard growth medium BG 11. Cu (II) concentration of 1.0 mg/L could accelerate the growth of <i>Scenedsmus</i> sp., and the highest biomass was 57.2 g/m² in 8 days. Moreover, the highest biomass mean values was 59.5 g/m², 57.1 g/m^2, and 58.1 g/m², respectively, when tetracycline concentration was 20.0 mg/L, norfloxacin concentration was 100.0 mg/L and sulfadimidine concentration was 10.0 mg/L. The removal efficiency of ammonia nitrogen, copper, tetracycline, norfloxacin and sulfadimidine with <i>Scenedsmus</i> sp. at their optimal initial concentration by biofilm attached culture was 85.2%, 64.6%, 74.6%,71.2%, and 62.3%, respectively. This study provides a theoretical basis for the purification of refractory substances from swine wastewater.