Development of a Regeneration Technique for Aluminum-Rich and Iron-Rich Phosphorus Sorption Materials

Isis S P C Scott,Chi-Hua Huang,Chad J Penn

doi:10.3390/w12061784

Isis S P C Scott, Chi-Hua Huang + Show 1 more

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https://doi.org/10.3390/w12061784

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Abstract

The reduction of dissolved phosphorus (P) transport to water systems is of critical importance for water quality. Phosphorus sorption materials (PSMs) are media with high affinity for dissolved P, and therefore serve as the core components of P removal structures. These structures can intercept dissolved P in surface and subsurface flows, before discharge into water bodies. While the P removal ability of PSMs has been extensively studied, lesser is known about the capacity to regenerate and recover P from P-saturated PSMs. This article evaluates a methodology to recover the P removal ability of aluminum- and iron-rich P-saturated PSMs. A series of flow-through experiments were conducted, alternating between P sorption (0.5 and 50 mg L − 1 P) and desorption with potassium hydroxide (KOH; 5 or 20 pore volumes [PV]), varying residence times (0.5 min and 10 min), and number of recirculations (0, 6 and 24). Across two cycles of sorption-desorption, Alcan, Biomax and PhosRedeem showed an average P recovery of 81%, 79%, and 7%, with standard deviation of 10%, 21% and 6%, respectively. The most effective regeneration treatment was characterized by the largest KOH volume (20 PV) and no recirculation, with up to 100% reported P recovery. Although KOH at 5 PV was less effective, the use of recirculation did increase P recovery. The lifetime of Al/Fe-dominated PSMs in P removal structures can be extended through feasible regeneration techniques demonstrated in this study, for both high and low P concentration scenarios.

Highlights

Phosphorus Sorption Materials (PSMs) are media with a high affinity for phosphorus (P) and the core of P removal structures, i.e., landscape-scale filters able to intercept surface and subsurfaceP-rich water
We evaluated the degree of reversibility of P adsorption by Al/Fe compounds and, based on that, we aimed to develop a regeneration strategy for Al/Fe-rich PSMs, in order to improve cost and longevity of P removal structures
We first discussed the P removal ability of the tested PSMs as measured in the flow-through experiments we evaluated proposed treatments

Summary

Introduction

Phosphorus Sorption Materials (PSMs) are media with a high affinity for phosphorus (P) and the core of P removal structures, i.e., landscape-scale filters able to intercept surface and subsurfaceP-rich water. Phosphorus Sorption Materials (PSMs) are media with a high affinity for phosphorus (P) and the core of P removal structures, i.e., landscape-scale filters able to intercept surface and subsurface. (2) manufactured materials; or (3) industrial residuals Their ability to bind with dissolved P has been amply studied and several media have been tested to that end, including steel slag, acid mine drainage residuals, limestone, and gypsum [1,2]. A common characteristic among PSMs is their high affinity for dissolved P due to their calcium (Ca), magnesium (Mg), iron (Fe), or aluminum (Al) contents. These elements are responsible for actively retaining P from flowing waters through different mechanisms. Calcium- or Mg-rich media remove dissolved P primarily by precipitation, forming solid

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