The metabolic activity of denitrifying microorganisms accumulating polyphosphate in response to addition of fusel oil

Agnieszka Tuszynska,Magdalena Kaszubowska,Przemyslaw Kowal,Slawomir Ciesielski,Jacek Makinia

doi:10.1007/s00449-018-2022-0

Abstract

The effect of distillery waste product (fusel oil) as an alternative external organic carbon source (EOCS) was investigated in terms of the metabolic properties of denitrifying polyphosphate accumulating organisms (DPAOs). Samples of the non-acclimated biomass were collected from a local full-scale wastewater treatment plant employing A2/O type bioreactors. The acclimated biomass was obtained after cultivation (with fusel oil added) in a bench-scale reactor with a process configuration similar to the full-scale bioreactor. Changes in the functional properties of the biomass were investigated by measuring the phosphate release/uptake rates (PRRs and PURs), and nitrate utilization rates (NURs) with fusel oil in anaerobic-anoxic batch tests. Furthermore, a validated extended Activated Sludge Model no 2d (ASM2d) was used as a supporting tool to analyze the experimental results and estimate the contribution of DPAOs to the overall denitrification. In the non-acclimated biomass with fusel oil, the PRRs, PURs and NURs were low and close to the rates obtained in a reference test without adding EOCS. With the acclimated biomass, the PUR and NUR increased significantly, i.e., 3.5 and 2.7 times, respectively. In the non-acclimated biomass, approximately 60.0 ± 3.6% and 20.0 ± 2.2% of the total NUR was attributed to the utilization of endogenous carbon and examined EOCS, respectively. The remaining portion (20% of the total NUR) was attributed to PHA utilization (linked to PO4-P uptake) by DPAOs. With the acclimated biomass, the contribution of the EOCS to the NUR increased to approximately 60%, while the contribution of the endogenous carbon source decreased accordingly. Very accurate predictions of PURs and NURs (R2 = 0.97–1.00) were obtained with the extended ASM2d. Based on model simulations, it was estimated that the activity of DPAOs and denitrifying ordinary heterotrophic organisms corresponded to approximately 20% and 80% of the total NUR, respectively.

Highlights

The successful operation of existing biological nutrient removal (BNR) wastewater treatment plants (WWTPs) depends to a great extent on the availability of sufficient amounts of appropriate organic compounds
In the combined N and P systems, these compounds should satisfy the needs of three microbial groups, including denitrifying “ordinary” heterotrophs, “ordinary” polyphosphate accumulating organisms (PAOs)—performing enhanced biological P removal (EBPR) in the traditional anaerobic/aerobic cycle—and denitrifying PAOs (DPAOs)—performing EBPR and denitrification in the provision of the anaerobically stored polyhydroxy-alkanoates (PHA)
The combination of the two processes by DPAOs is a sustainable solution as it can save aeration and carbon source required for denitrification, 3 Vol.:(0123456789)

Summary

Introduction

The successful operation of existing biological nutrient removal (BNR) wastewater treatment plants (WWTPs) depends to a great extent on the availability of sufficient amounts of appropriate (biodegradable) organic compounds (carbon sources). The first group includes commercial products, such as methanol, ethanol, acetic acid, sodium acetate or glucose Despite their proved efficiency, several recent studies emphasized economical barriers for the practical use in WWTPs [5–8]. Due to high costs of the commercial compounds, various industrial byproducts or waste materials have received more attention as the “alternative” EOCS. Such an approach is in accordance with the principle of “zero waste” strategy implemented in the European Union to stimulate the development of new waste reuse technologies [9]

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