Removal of Ammonia and Production of Biodiesel by Chlorella sp. USTB-01

Abstract

The release of ammonia from the industry of rare earth leads to harmful cyan bacterial bloom and consumption of non-renewable oil resources cause the energy crisis. Using an isolated strain of Chlorella sp. USTB-01, which can grow both autotrophically and heterotrophically, to remove ammonia nitrogen from the rare-earth wastewater and to produce biodiesel were investigated. The results showed that in heterotrophic batch culture, 3.3 g /L of dry cell concentration(DWC) of Chlorella sp. USTB-01 and 92.2% removal ratio of ammonia nitrogen were obtained when glucose was used as sole carbon source. A novel ferment or-helical combined photo bio reactor was designed and used to cultivate Chlorellasp. USTB-01 for removal of ammonia nitrogen from rare-earth wastewater, which indicated that the maximum DWC of 4.9g/L was obtained at 72 h and the highest ammonia nitrogen removal ratio of 99.2% was achieved when 2% CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> was injected and the mixture of glucose and NaOH (10:1) was automatically fed to control pH of 6.5. In the harvested microalgal cells, the biodiesel synthesis by Chlorella sp. USTB-01 mainly contains C16 and C18 fat acids methyl ester, which were very suitable for the conversion of high quality of biofuel. This study is very important in both the treatment of rare earth waste water and production of biodiesel using Chlorellasp. USTB-01.