On the effect of xenobiotics on bacterial nitrite oxidation | Health & Environmental Research Online (HERO)

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Citation
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HERO ID

1339304

Reference Type

Book/Book Chapter

Title

On the effect of xenobiotics on bacterial nitrite oxidation

Author(s)

Dokianakis, SN; Kornaros, M; Lyberatos, G

Year

2005

Book Title

Proceedings of the International Conference on Environmental Science and Technology

Page Numbers

A311-A316

Web of Science Id

WOS:000237753600047

Abstract

Among organic chemicals, wastewater entering treatment plants contains many xenobiotic compounds such as NonylPhenols (NPs), NonylPhenolEthoxylates (NPEOs), Linear Alkylbenzene Sulfonates (LAS) and Polycyclic Aromatic Hydrocarbons (PAHs). Although they are either physicochemically or biologically removed in well-operating wastewater treatment plants they have been repeatedly detected in the effluents of many municipal sewage treatment plants. Because of their properties, these compounds may cause adverse effects to many living organisms even in minute concentrations. Their presence in the influents of municipal wastewater treatment plants may inhibit irreversibly sensitive biological processes such as nitrification. The second step of nitrification i.e. oxidation of nitrite to nitrate (nitritification) is particularly sensitive. Inhibition of this step under uncontrolled conditions may lead to accumulation of nitrite nitrogen, a form of nitrogen which is particularly toxic, in the plant effluents. The aim of this work was to study the effect of the presence of five different xenobiotics to a mixed culture of nitrite-oxidizing bacteria isolated from activated sludge. The xenobiotics; which were tested include NP, NPEO, LAS, di(2-ethylhexyl) phthalate (DEHP) and phenanthrene. Batch experiments were conducted in parallel for each compound to assess the inhibitory impact on the nitritification process at different concentrations. The nitrite oxidizing bacteria used in these experiments were fed with a synthetic medium containing the xenobiotic compound and NaNO2 as substrate. Different effects were observed for each of the compounds tested in this study. NP and NPEO presented a remarkable inhibitory effect on nitrite oxidation rate whereas DEHP, phenanthrene and LAS caused a moderate inhibition in the performance of nitrite oxidizing bacteria.

Keywords

nitrite oxidizers; nitrification; xenobiotics; surfactants; inhibition; activated sludge

Editor(s)

Lekkas, TD