Conversion of Soluble Recalcitrant Phosphorus to Recoverable Orthophosphate Form Using UV/H₂O₂

Authors

Kaushik Venkiteshwaran, Marquette UniversityFollow
Eileen Kennedy, Marquette University
Caitlin Graeber, Marquette University
Synthia P. Mallick, Marquette UniversityFollow
Patrick J. McNamara, Marquette UniversityFollow
Brooke K. Mayer, Marquette UniversityFollow

Document Type

Article

Publication Date

9-2021

Publisher

Elsevier

Source Publication

Chemosphere

Source ISSN

0045-6535

Original Item ID

10.1016/j.chemosphere.2021.130391

Abstract

Soluble non-reactive phosphorus (sNRP), such as inorganic polyphosphates and organic P, is not effectively removed by conventional physicochemical processes. This can impede water resource reclamation facilities’ ability to meet stringent total P regulations. This study investigated a UV/H₂O₂ advanced oxidation process (AOP) for converting sNRP to the more readily removable/recoverable soluble reactive P (sRP), or orthophosphate, form. Synthetic water spiked with four sNRP compounds (beta-glycerol phosphate, phytic acid, triphosphate, and hexa-meta phosphate) at varying H₂O₂ concentration, UV fluence, pH, and temperature was initially tested. These compounds represent simple, complex, organic, and inorganic forms of sNRP potentially found in wastewater. The efficiency of sNRP to sRP conversion depended on whether the sNRP compound was organic or inorganic and the complexity of its chemical structure. Using 1 mM H₂O₂ and 0.43 J/cm² (pH 7.5, 22 °C), conversion of the simple organic beta-glycerol phosphate to sRP was 38.1 ± 2.9%, which significantly exceeded the conversion of the other sNRP compounds. Although conversion was achieved, the electrical energy per order (E_EO) was very high at 5.2 × 10³ ± 5.2 × 10² kWh/m³. Actual municipal wastewater secondary effluent, with sNRP accounting for 15% of total P, was also treated using UV/H₂O₂. No wastewater sNRP to sRP conversion was observed, ostensibly due to interference from wastewater constituents. Wastewater utilities that have difficulty meeting stringent P levels might be able to target simple organic sNRP compounds, though alternative processes beyond UV/H₂O₂ need to be explored to overcome interference from wastewater constituents and target more complex organic and inorganic sNRP compounds.

Comments

Accepted version. Chemosphere, Vol. 278 (September 2021). DOI. © 2021 Elsevier. Used with permission.

Recommended Citation

Venkiteshwaran, Kaushik; Kennedy, Eileen; Graeber, Caitlin; Mallick, Synthia P.; McNamara, Patrick J.; and Mayer, Brooke K., "Conversion of Soluble Recalcitrant Phosphorus to Recoverable Orthophosphate Form Using UV/H₂O₂" (2021). Civil and Environmental Engineering Faculty Research and Publications. 264.
https://epublications.marquette.edu/civengin_fac/264