PREFACE

The constructed wetland (CW) serves to for water purification in the sparsely populated areas.However, the use of CW for organic matter, nitrogen removal, and heavy metal removal is limited to the low temperature, denitrification carbon source, electron donors and so on. Therefore, the enhancement of performance efficiency of CW was got focus in recent years. The aim of this book was to briefly reviews and introduces the history and development of CW, and the mechanism and problems of CW for contaminant removal. In addition, we introduced the coupled methods of bio-electrode methods (bio-electrode film, micro-electric filed and microbial fuel cell) with CW to improve the treatment performance of CW for low C/N ratios wastewater, heavy metal, nitrate removal and so on.

Firstly, we demonstrated that the use of CW combined with biofilm-electrode reactor and integrating biofilm-electrode with CW was benefit for the removal nitrogen from wastewater based on the enhancement of relative abundance of autotrophic bacteria. Secondly, the micro-electric filed coupled with CW system was performed to strengthen the removal of heavy metals during the wastewater treatment. Thirdly, the effects of operational conditions (pH, COD concentrations, anode and cathode electrode materials, substrate material sizes, and plant types) on the bioelectricity generation and wastewater treatment performance was investigated in a hybrid system of integrating microbial fuel cell into CW. Notably, the high-throughput sequencing analysis was employed to study the diversification and richness of microbial community, which indicated that the evenness, richness and distribution of the microorganisms were apparently changed with the application of these methods into CW. Through the development of these methods, the contaminant removal performance of CW was significantly enhanced for the treatment of wastewater. Thus, this book can serve as an implication and reference for researchers to study the mechanisms of water purification in the coupled systems of CW.

This book is finished under the support of the National Key Technology Support (Grant Nos. 2015BAB07B09), National Nature Science Foundation of China (Grant Nos. 51679041，91547209 and 41571037).

Wang Junfeng

Guangzhou, 2018