Nutrient Removal during Stormwater Aquifer Storage and Recovery in an Anoxic Carbonate Aquifer. Issue 2 (1st March 2018)

• Record Type: Journal Article
• Authors: Vanderzalm, Joanne L.; Page, Declan W.; Dillon, Peter J.; Barry, Karen E.; Gonzalez, Dennis
• Is Part Of: Journal of Environmental Quality. Volume 47:Issue 2(2018)
• Page Start: 276
• Page End: 286
• Publication Date: 2018-03-01
• Subjects: Agricultural ecology -- Periodicals; Environmental engineering -- Periodicals; Pollution -- Periodicals; 630
• DOI: 10.2134/jeq2016.12.0486
• Languages: English
• ISSNs: 0047-2425

Abstract

Abstract : Stormwater harvesting coupled to managed aquifer recharge (MAR) provides a means to use the often wasted stormwater resource while also providing protection of the natural and built environment. Aquifers can act as a treatment barrier within a multiple‐barrier approach to harvest and use urban stormwater. However, it remains challenging to assess the treatment performance of a MAR scheme due to the heterogeneity of aquifers and MAR operations, which in turn influences water treatment processes. This study uses a probabilistic method to evaluate aquifer treatment performance based on the removal of total organic C (TOC), N, and P during MAR with urban stormwater in an anoxic carbonate aquifer. Total organic C, N, and P are represented as stochastic variables and described by probability density functions (PDFs) for the "injectant" and "recovery"; these injectant and recovery PDFs are used to derive a theoretical MAR removal efficiency PDF. Four long‐term MAR sites targeting one of two tertiary carbonate aquifers (T1 and T2) were used to describe the nutrient removal efficiencies. Removal of TOC and total N (TN) was dominated by redox processes, with median removal of TOC between 50 and 60% at all sites and TN from 40 to 50% at three sites with no change at the fourth. Total P removal due to filtration and sorption accounted for median removal of 29 to 53%. Thus, the statistical method was able to characterize the capacity of the anoxic carbonate aquifer treatment barrier for nutrient removal, which highlights that aquifers can be an effective long‐term natural treatment option for management of water quality, as well as storage of urban stormwater. Core Ideas: Aquifer treatment capacity for C, N, and P was quantified in four long‐term ASR sites. Robust median TOC removal was 50 to 60% in an anoxic carbonate aquifer. Median TN removal was at least 40% at three sites and inhibited by pH >8 at a fourth. TP removal was 29 to 53%; however, sorption capacity may be limited.