Understanding nutrient dynamics for effective stormwater treatment design

Buddhi Wijesiri; An Liu; Nandika Miguntanna; Beibei He; Ashantha Goonetilleke

doi:10.1016/j.scitotenv.2022.157962

Understanding nutrient dynamics for effective stormwater treatment design

Sci Total Environ. 2022 Dec 1:850:157962. doi: 10.1016/j.scitotenv.2022.157962. Epub 2022 Aug 11.

Authors

Buddhi Wijesiri¹, An Liu², Nandika Miguntanna³, Beibei He⁴, Ashantha Goonetilleke³

Affiliations

¹ College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, PR China; School of Civil and Environmental Engineering, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Qld 4001, Australia.
² College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, PR China; Water Science and Environmental Engineering Research Center, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, PR China. Electronic address: liuan@szu.edu.cn.
³ School of Civil and Environmental Engineering, Queensland University of Technology (QUT), GPO Box 2434, Brisbane, Qld 4001, Australia.
⁴ College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, PR China.

PMID: 35964744
DOI: 10.1016/j.scitotenv.2022.157962

Abstract

Current stormwater quality modelling tools lack robust mathematical replication of nutrient entrainment in runoff. This makes it challenging to design effective stormwater treatment systems such as nature based solutions with adequate resilience to future changes in nutrient inputs in urban environments. Consequently, poorly treated stormwater can be discharged into receiving waters, leading to nutrient enrichment and in turn, environmental and human health impacts. This study integrated empirically based with statistical modelling techniques to incorporate nutrient dynamics into commonly used Intensity-Frequency-Duration (IFD) distributions of design rainfall. Field based nutrient wash-off experiments were conducted to understand nutrient behaviour during a runoff event. New mathematical formulations were derived to describe the decay (wash-off) of nutrients. Rainfall intensity, duration and initially accumulated pollutant load exert positive influence on the decay of nitrogen and phosphorous, while organic carbon has a negative impact on phosphorus decay. It was also evident that nitrogen species would decay at a similar rate, while phosphorus species may decay at different rates. Compared to nitrogen species, phosphorous species were found more likely to be washed-off during a rainfall event. Using the mathematical formulations developed, wash-off of nitrogen and phosphorous was simulated for 435 very frequent and frequent/infrequent design rainfall events leading to the creation of Intensity-Frequency-Duration-Wash-off (IFDW) curves. Analysis of uncertainty associated with IFDW indicated that total phosphorous could be completely washed-off during most of the design rainfall events, while total nitrogen would only be completely washed-off by very few events that are rarer than 10 % AEP (annual exceedance probability). IFDW can act as a tool for supporting effective stormwater treatment design in order to promote sustainable stormwater management and reuse.

Keywords: Design rainfall; Stormwater management; Stormwater pollutant processes; Stormwater pollutants; Stormwater quality.

MeSH terms

Carbon
Environmental Monitoring
Environmental Pollutants*
Humans
Nitrogen / analysis
Nutrients
Phosphorus / analysis
Rain
Water Movements
Water Pollutants, Chemical* / analysis
Water Purification*
Water Supply

Substances

Environmental Pollutants
Water Pollutants, Chemical
Phosphorus
Carbon
Nitrogen