title: Removal of UV 254 nm matter and nutrients from a photobioreactor-wetland system.
abstract: The output of organic pollutants and excessive nutrients in intensive agricultural areas has frequently occurred, which easily lead to pollution events such as harmful algal blooms in downstream aquatic ecosystems. A photobioreactor-wetland system was applied to remove UV(254 nm) matter and dissolved nutrients discharged from an intensive agricultural area in the Kunming region of western China. The photobioreactor-wetland system was composed of two main components: an autotrophic photobioreactor with replanted macrophytes and a constructed wetland. The results showed that there was a significant correlation between UV(245)(nm) absorbance and chemical oxygen demand (COD) concentration in the effluent of the agricultural ecosystem. When the hydraulic load of the photobioreactor-wetland system was 500 m(3)day(-1), the UV(254 nm) absorbance was dramatically reduced, and dissolved nutrients such as TDP, NO(3)-N and NH(4)-N were effectively removed. The overall average removal efficiencies were as follows in relatively steady-state conditions: UV(254 nm) matter (66%), TDP (71%), NO(3)-N (75%) and NH(4)-N (65%). Simpson's diversity index of zoobenthos indicated that the system could increase the zoobenthic diversity and improve the growth conditions of the zoobenthos habitat. The results also showed that the photobioreactor-wetland system could remove the UV(254 nm) matter and dissolved nutrients, providing a promising bio-measure for reducing the risk of pollution event occurrences in downstream surface waters.
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Sciences, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Wu
authors.forename: Jiangzhou
authors.initials: J
authors.lastname: He
authors.forename: Zhengyi
authors.initials: Z
authors.lastname: Hu
authors.forename: Linzhang
authors.initials: L
authors.lastname: Yang
authors.forename: Naiming
authors.initials: N
authors.lastname: Zhang
mesh_terms: D019149:Bioreactors; D010777:Photochemistry; D014466:Ultraviolet Rays; D053833:Wetlands