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  • Phosphorus recovery by ion exchange in a solid carbonate: modeling of the process.

Phosphorus recovery by ion exchange in a solid carbonate: modeling of the process.

Environmental science and pollution research international (2019-05-06)
Luis A Cueto, Anne M Hansen
ABSTRACT

Phosphorus (P) is a nutrient for plant growth but also a pollutant in water bodies causing eutrophication. The source of P is mainly human and animal wastewater and runoffs from different land uses. The objective of the present study is to evaluate P removal and recovery processes by ion exchange (IE) with solid carbonate (SC) in biodigestor-treated swine effluent (BTSE) using hydrogeochemical modeling. For this, BTSE compositions were obtained by literature review. A synthetized and characterized SC was used and the ion exchange site concentration ([SC-IE]) and the IE constants (Kie) were obtained experimentally and applied to model P and major anion removal and recovery processes. P recovery was evaluated for different BTSE compositions and several concentrations of SC, dissolved P (HPO42-), competing anions such as SO42-, and CO32-. The simulations suggest that a [SC-IE]:[HPO4] of 1.4 molar ratio would allow the recovery of 90% of HPO4 in BTSE, and at average alkalinity concentrations in BTSE, CO32- would compete with HPO4 for the SC-IE. The P recovery by the SC-IE process was compared with two other methods commonly used in P removal from BTSE: removal with aluminum sulfate and precipitation of struvite as a function of pH. The results suggest that SC-IE is the most efficient method in the pH range of BTSE. Besides, HPO42- was readily recovered as inorganic P that may be reused in agriculture and industrial processes.

MATERIALS
Product Number
Brand
Product Description

Supelco
Chloride Test, photometric, 2.5-250 mg/L (Cl-), Spectroquant®
Supelco
TOC Cell Test, photometric, 5.0-80.0 mg/L (TOC), Spectroquant®
Supelco
Phosphate Cell Test, photometric, 0.05-5.00 mg/L (PO4-P), 0.2-15.3 mg/L (PO43-), 0.11-11.46 mg/L (P2O5), Spectroquant®
Supelco
Sulfate Cell Test, photometric, 50-500 mg/L (SO42-), Spectroquant®