Elsevier

Water Research

Volume 169, 1 February 2020, 115228
Water Research

Stress-induced assays for polyphosphate quantification by uncoupling acetic acid uptake and anaerobic phosphorus release

https://doi.org/10.1016/j.watres.2019.115228Get rights and content
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Highlights

  • Two proposed methods to uncouple P-release and HAc uptake for poly-P quantification.

  • EDTA is a simple, user-friendly and cost-effective way to quantify poly-P content.

  • Exposure time for 9 h, pH and EDTA concentration are important for batch tests.

  • Grind and sonication do not substantially boost anaerobic P-release.

Abstract

Phosphorus has been successfully eliminated from wastewater by biological techniques of enhanced biological phosphorus removal (EBPR) process, which relies on a specific microbiota of polyphosphate accumulating organisms (PAOs) that accumulate phosphate as polyphosphates (poly-P). Most methods for quantification of poly-P pools suffer from low accuracy and specificity. More powerful and implementable P-analysis tools are required for poly-P quantification, which will help in improved evaluation of processes in laboratory and full-scale EBPR systems. This study developed two methods to quantify poly-P pools by releasing the poly-P from the cell. During experimental optimization, it was observed that two different methods resulted in the highest phosphate release: acetate addition at a pH of 4.8 and exposure to EDTA solution with a concentration of 1% (w/v). Treatment with EDTA resulted in a higher amount of phosphate release from all sludge samples. This was characterized by P-release of 1.5–2.5 times higher than the control tests. In contrast, treatments with acetate addition at a low pH exhibited that P-release depended upon the types of the sludge samples. The highest P-release amount and rate were found in highly-enriched PAO sludge samples, but with fewer influences on the sludge collected from WWTP, which may be attributed to the lower fraction of PAOs in the sludge. Overall, the proposed approaches to quantify the poly-P concentration can be applied in simple, user-friendly, and cost-effective ways.

Keywords

Polyphosphate (poly-P)
Enhanced biological phosphorus removal (EBPR)
Polyphosphate-accumulating organisms (PAOs)
Quantification

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