Impact of changing environmental factors and species competition on iron filings‐based green environmental media for nutrient removal in stormwater treatment

Abstract

Iron filings‐based green environmental media (IFGEM) is a new type of green sorption media that may be applied to heterogeneous environments for removing nutrients. To confirm the reliability and efficacy of this new green sorption media, multiple factors must be considered for a holistic assessment, primarily temperature effect, varying influent concentration, changing pH value, varying iron filing content, presence of iron filings, and interaction (competition) between nutrient species such as nitrogen and phosphorus. In this study, two IFGEM recipes were selected to compare against one control (natural soil). Whereas IFGEM‐1 is made of 96.2% fine sand and 3.8% iron filings (by volume), IFGEM‐2 contains 80% sand, 10% tire crumb, 5% pure clay, and 5% iron filings (by volume). IFGEM‐1 can function well from 12 to 35°C, while IFGEM‐2 can work well only at the optimal temperature of 12°C. IFGEM‐2 may adapt to a wider pH range from acidic to neutral, while IFGEM‐1 performs well only at the neutral pH condition. When varying influent concentrations to test the sensitivity of both IFGEM recipes, our findings indicated that higher influent concentration results in higher removal efficiency. Higher iron filing content exhibits better nutrient recovery potential, and nitrogen and phosphorus compete for more shares of adsorption/adsorption capacity. © 2018 American Institute of Chemical Engineers Environ Prog, 38:e13087, 2019

A comprehensive review on the long-term performance of stormwater biofiltration systems (SBS): Operational challenges and future directions

“…Phosphorus is removed by plants and microbial uptake or absorbed by the filter media (Marvin et al, 2020). Many studies focused on the efficacy and the mechanism involved in nitrogen (Jiang et al, 2017;Tian et al, 2019;Wu et al, 2017) and phosphorus (Chang et al, 2019;Zhang et al, 2018a) removal, but few studies have examined the long-term performance in SBS (Table 2). Previous research suggested that SBS could reduce nutrients after a long-term operation.…”

Urban stormwater characterization, control, and treatment

“…Iron filings as an additive to bioretention media were shown to improve the removal of N and P in a bioretention column study (Chang, Wen, & Wanielista, 2019). Combinations of sand with a 3.8% and a 5% content iron filing mix (v/v) were compared with a natural soil control.…”

Runoff regulation and nitrogen and phosphorus removal performance of a bioretention substrate with HDTMA-modified zeolite

“…In addition to regulating K s , different amendments were used in bioretention media to improve its water purification ability. Studies showed that amendments such as blast furnace slag, biochar, water treatment residuals (WTRs), and iron filings could improve the total phosphorus (TP) and total nitrogen (TN) removal ability of the bioretention media (Li et al, 2016;Chang et al, 2019;Poor et al, 2019;Zhou et al, 2022).…”