Innovative Phosphorus Removal and Recovery Strategies

A comparison of advanced oxidation and traditional chemical treatment: (A) anthropogenic inputs such as agricultural runoff,

(B) traditional chemical treatment, (C) removal of PO4 and NOM with the persistence of DOP in the water body, (D) oxidation of

DOP to PO4 followed by traditional chemical treatment, and (E) removal of PO4, DOP, and NOM from the water body.

This research was funded in part by a USP

undergraduate research award to JC. We

would like to thank Hugo Sindelar for his

assistance with experiments.

Jacquline Cooke (B.S., 2012) Dr. Treavor H. Boyer

Overview and Objectives

Excess phosphorus (P) can pose significant challenges to the quality of water bodies. Present chemical technologies are able to

remove inorganic P while organic P remains a challenge. Oxidative degradation procedures for dissolved organic compounds

provide a means of chemical treatment. Specifically, oxidation of organic pollutants by UV/H2O2 generates hydroxyl radicals that

react with organic compounds. Hence, the goal of this research is to provide an evaluation of the effectiveness of oxidizing

dissolved organic P (DOP) to the more readily treatable orthophosphate (PO4) using UV/H2O2 treatment as a model advanced

oxidation process (AOP). The specific objectives of this work are: (1) to evaluate the effect of UV/H2O2 treatment on changes in

DOP and PO4 in model waters with varying compositions, (2) to investigate the most effective combination of UV exposure time

and H2O2 concentration to oxidize DOP to PO4, and (3) to compare the decrease in DOP to that of bulk NOM.

Conclusions

Treatment with UV/H2O2 (50 mg/L H2O2 and 60 min UV) yielded oxidation (80-100%) of DOP to PO4. Test waters

were prepared with target concentrations for PO4 and DOP of 200 and 100 µg/L P, respectively, and a target

concentration for NOM of 10 mg/L C. An approximate model for Everglades NOM was achieved by combining TEP

and SR NOM. TEP was used as a surrogate for DOP.

Model waters with varying compositions of alkalinity, chloride, bromide, iodide, and nitrate were used to test the effect

of water chemistry on DOP oxidation. Because of the powerful oxidation conditions used (50 mg/L H2O2 and 60 min

UV), the effect of the test water chemistry on DOP oxidation was not observed.

Treatment combinations with varying doses of H2O2 and UV were tested to determine an effective combination to

oxidize DOP to PO4. Treatment combinations of 50 mg/L H2O2 and 6 min UV and 25 mg/L H2O2 and 12 min UV were

ineffective at oxidizing (30-40%) DOP. Oxidation (50-90%) of DOP to PO4 was achieved with a treatment

combination of 50 mg/L H2O2 and 12 min UV. Treatment with 50 mg/L H2O2 and 12 min UV was determined effective

at oxidizing DOP.

Analysis of the percent removal of DOP versus that of NOM concluded that UV/H2O2 treatment as a model AOP is

preferential toward the oxidation of NOM before that of DOP.

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Treavor H. Boyer, Ph.D. ~ Assistant Professor ~ Department of Environmental Engineering Sciences ~ University of Florida

thboyer@ufl.edu ~ 352.846.3351 ~ www.ees.ufl.edu/homepp/boyer ~ www.twitter.com/WaterWeUpTo