REDUCTION OF NON-POINT SOURCE POLLUTION IN THE YONG’AN RIVER BY CONSTRUCTED WETLAND BASED ON 9 YEARS OF MONITORING

Highlights

● The primary pollutants of Yong’an River are total nitrogen and nitrate

● Constructed wetland can effectively remove nitrate and phosphorus

● Plant decay reduces removal efficiency for ammonium and organic matter

Abstract

The agricultural and livestock activities surrounding the rivers flowing into the lakes have caused non-point source pollution, leading to excessive amounts of nutrient salts in downstream rivers. Introducing river water into constructed wetlands along river course has proven to be an effective solution for decreasing nitrogen (N) and phosphorus (P) loads. This paper reports 9 years of monitoring the Yong’an River and its surrounding constructed wetlands in the upper reaches of Erhai Lake, located in Yunnan Province, China. This study analyzed the main types of pollutants in the river, and evaluated the removal efficiency of pollutants by the constructed wetlands. The findings indicate that total nitrogen (TN) and nitrate nitrogen (NO₃^–-N) are the primary pollutants in the Yong’an River, which exhibit variation throughout the year corresponding to the alternating wet and dry seasons. Although constructed wetlands are effective in removing NO₃^–-N and P, their efficacy in removing ammonium nitrogen (NH₄⁺-N) and organic pollutants is limited. This limitation can be attributed to the lack of timely disposal of aquatic plant residues. This research contributes to the understanding of the potential issues that may arise during the extended use of constructed wetlands and provides solutions to address them.

Graphical abstract

Keywords

inflowing rivers / surface-flow constructed wetland / nutrients / long-term monitoring

References

[1] Conley D J, Paerl H W, Howarth R W, Boesch D F, Seitzinger S P, Havens K E, Lancelot C, Likens G E. Ecology controlling eutrophication: nitrogen and phosphorus. Science, 2009, 323(5917): 1014–1015

[2] Paerl H W, Gardner W S, McCarthy M J, Peierls B L, Wilhelm S W. Algal blooms: noteworthy nitrogen. Science, 2014, 346(6206): 175

[3] Peng J Y, Jin C L, Wu Y, Hou Z Y, Gao S J, Chu Z S, Zheng B H. Modeling non-point source nutrient loads with different cropping systems in an agricultural lake watershed in southwestern China: from field to watershed scale. Mathematics, 2022, 10(21): 4047

[4] Yang S B, Chen X L, Lu J Z, Hou X J, Li W K, Xu Q Q. Impacts of agricultural topdressing practices on cyanobacterial bloom phenology in an early eutrophic plateau lake, China. Journal of Hydrology, 2021, 594: 125952

[5] Walters D, Shrubsole D. Agricultural drainage and wetland management in Ontario. Journal of Environmental Management, 2003, 69(4): 369–379

[6] Shukla A, Parde D, Gupta V, Vijay R, Kumar R. A review on effective design processes of constructed wetlands. International Journal of Environmental Science and Technology, 2022, 19(12): 12749–12774

[7] Parde D, Patwa A, Shukla A, Vijay R, Killedar D J, Kumar R. A review of constructed wetland on type, treatment and technology of wastewater. Environmental Technology & Innovation, 2021, 21: 101261

[8] de-Bashan L E, Bashan Y. Recent advances in removing phosphorus from wastewater and its future use as fertilizer (1997–2003). Water Research, 2004, 38(19): 4222–4246

[9] Yang Y, Zhao Y Q, Liu R B, Morgan D. Global development of various emerged substrates utilized in constructed wetlands. Bioresource Technology, 2018, 261: 441–452

[10] Wu S B, Kuschk P, Brix H, Vymazal J, Dong R J. Development of constructed wetlands in performance intensifications for wastewater treatment: a nitrogen and organic matter targeted review. Water Research, 2014, 57: 40–55

[11] Li J H, Yang X Y, Wang Z F, Shan Y, Zheng Z. Comparison of four aquatic plant treatment systems for nutrient removal from eutrophied water. Bioresource Technology, 2015, 179: 1–7

[12] Jesus J M, Danko A S, Fiuza A, Borges M T. Effect of plants in constructed wetlands for organic carbon and nutrient removal: a review of experimental factors contributing to higher impact and suggestions for future guidelines. Environmental Science and Pollution Research International, 2018, 25(5): 4149–4164

[13] Zhou Y C, Luo S, Yu B H, Zhang T Q, Li J, Zhang Y P. A comparative analysis for the development and recovery processes of different types of clogging in lab-scale vertical flow constructed wetlands. Environmental Science and Pollution Research International, 2018, 25(24): 24073–24083

[14] Liu X, Zhao Y F, Zhang X L, Kong H N, Lin Y. Plant community diversity in Dengbeiqiao constructed wetland and ecological revetment of Yong’an River in Erhai region in 2012. Wetland Science, 2018, 16(1): 45−50 (in Chinese)

[15] Yan C L, Zhao M, Li Z K, Li J, Duan Y S. Water characteristics of inflow rivers in northern Erhai Lake and their impact on the northern lake area. Environmental Engineering, 2020, 38(12): 59–63, 5 (in Chinese)

[16] Li Y, Liu H B, Lei Q L, Hu W L, Wang H Y, Zhai L M, Ren T Z, Lian H Z. Impact of human activities on net anthropogenic nitrogen inputs (NANI) at township scale in Erhai Lake basin. Environmental Sciences, 2018, 39(9): 4189−4198 (in Chinese)

[17] Wu W H, He X J, Wu H L, Wang X Z, Shen J. Identification of sources of nitrate in the Yong’an River with isotopic technology. Journal of Ecology and Rural Environment, 2016, 32(5): 802−807 (in Chinese)

[18] Gachango F G, Pedersen S M, Kjaergaard C. Cost-effectiveness analysis of surface flow constructed wetlands (SFCW) for nutrient reduction in drainage discharge from agricultural fields in denmark. Environmental Management, 2015, 56(6): 1478–1486

[19] Wu H L. Plant root exudates and their function on the nitrogen removal in constructed wetlands. Dissertation for the Doctoral Degree. Shanghai: Shanghai Jiao Tong University, 2018 (in Chinese)

[20] Rehman F, Pervez A, Khattak B N, Ahmad R. Constructed wetlands: perspectives of the oxygen released in the rhizosphere of macrophytes. Clean, 2017, 45(1): 1600054

[21] Liang Q B, Hou L, Li N F, Chen X, Wang K Q. Long-term effects and influencing factors of nitrogen retention in a surface flow constructed wetland in the northern part of Erhai Lake. Journal of Agro-Environmental Sciences, 2020, 39(7): 1585−1593 (in Chinese)

[22] Wang Z Y, Wang X Z, Lin Y, Tong X N, Kong H N. Simulation of nitrogen transfer processes in a constructed wetland for a lightly contaminated river. Research of Environmental Sciences, 2014, 27(6): 602−607 (in Chinese)

[23] Tong X N. Relationships between plantting reed and nitrogen removal effectiveness in subsurface constructed wetlands. Thesis for the Master’s Degree. Shanghai: Shanghai Jiao Tong University, 2014 (in Chinese)

[24] Ling Z W. Study on treatment of low-contaminated water with aerating constructed wetland. Thesis for the Master’s Degree. Shanghai: Shanghai Jiao Tong University, 2013 (in Chinese)

[25] Wu H L, Wang X Z, He X J, Zhang S B, Liang R B, Shen J. Effects of root exudates on denitrifier gene abundance, community structure and activity in a micro-polluted constructed wetland. Science of the Total Environment, 2017, 598: 697–703

[26] Al-Saedi R, Smettem K, Siddique K H M. The impact of biodegradable carbon sources on microbial clogging of vertical up-flow sand filters treating inorganic nitrogen wastewater. Science of the Total Environment, 2019, 691: 360–366

[27] Cui L H, Zhu X Z, Luo S M. The relationship between constructed wetland substrate phosphorous adsorption character and its physico-chemical properties. China Environmental Science, 2007, 27(2): 250−254 (in Chinese)

[28] Wan M H. Study on nitrogen and phosphorus removal by nutrient enrichment contructed wetland. Thesis for the Master’s Degree. Shanghai: Shanghai Jiao Tong University, 2011 (in Chinese)

[29] Beukes P C, Weeber M, Neal M, Thiange C, Burger D F. Evaluating nutrient abatement policies for a pastorally farmed catchment-lagoon ecosystem: a New Zealand case study. Agriculture, Ecosystems & Environment, 2023, 342: 108227

[30] Salimi S, Almuktar S A A A N, Scholz M. Impact of climate change on wetland ecosystems: a critical review of experimental wetlands. Journal of Environmental Management, 2021, 286: 112160

[31] Zhang S B. Effects of environmental factors on the community structure of denitrification in sediment of constructed wetland. Thesis for the Master’s Degree. Shanghai: Shanghai Jiao Tong University, 2017 (in Chinese)

[32] Li D, Ye B B, Hou Z Y, Chu Z S, Zheng B H. Long-term performance and microbial distribution of a filed-scale storing multi-pond constructed wetland with Ottelia acuminata for the treatment of non-point source pollution. Journal of Cleaner Production, 2020, 262: 121367

[33] Pavlineri N, Skoulikidis N T, Tsihrintzis V A. Constructed floating wetlands: a review of research, design, operation and management aspects, and data meta-analysis. Chemical Engineering Journal, 2017, 308: 1120–1132

Supplementary materials

The online version of this article at https://doi.org/10.15302/J-FASE-2023516 contains supplementary materials (Figs. S1–S8; Tables S1–S2).

Acknowledgements

This research was supported by National Key Research and Development Program of China (2021YFD1700400), Yunnan Fundamental Research Projects (202201AU070001) and Startup Fund for Young Faculty at SJTU (22X010500256).

Compliance with ethics guidelines

Huaji Liu, Jian Shen, Jimeng Feng, and Xinze Wang declare that they have no conflicts of interest or financial conflicts to disclose. This article does not contain any studies with human or animal subjects performed by any of the authors.

RIGHTS & PERMISSIONS

The Author(s) 2023. Published by Higher Education Press. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0)