Dynamics of nitrate and nitrite in saturated sand filters with enhanced substrate conditions for denitrifying bacteria

Substrate conditions for denitrifying bacteria were enhanced by adding carbon sources to a laboratory-scale sand filter system. Temperature, oxidation–reduction potential, and hydrogen ion concentration were measured through the recirculation of nitrogen-dosed wastewater and carbon sources that w...

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Main Authors: Al-Saedi, Rasha, Smettem, Keith, Stefanova, Katia, Siddique, Kadambot HM
Format: Journal Article
Published: Desalination Publications 2021
Online Access:http://hdl.handle.net/20.500.11937/82629
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author Al-Saedi, Rasha
Smettem, Keith
Stefanova, Katia
Siddique, Kadambot HM
author_facet Al-Saedi, Rasha
Smettem, Keith
Stefanova, Katia
Siddique, Kadambot HM
author_sort Al-Saedi, Rasha
building Curtin Institutional Repository
collection Online Access
description Substrate conditions for denitrifying bacteria were enhanced by adding carbon sources to a laboratory-scale sand filter system. Temperature, oxidation–reduction potential, and hydrogen ion concentration were measured through the recirculation of nitrogen-dosed wastewater and carbon sources that were mixed to encourage microbial growth, with denitrifying bacteria identified by standard plate counts. Two different external carbon sources (sucrose and ethanol) were added, with and without activated sludge amendments. Nitrate, nitrite, and chemical oxygen demand (COD) concentrations were monitored relative to an untreated control and a treatment with activated sludge under an initial hydraulic loading rate of 0.508 m3 /m2 d and a hydraulic retention time of 2.5 h. Nitrate decay rates were only significantly enhanced for the ethanol treatment without addition of activated sludge. Nitrite initially accumulated when carbon sources were added, but no accumulation was evident by the end of the experiment after 150 min. COD declined when carbon sources were added, but activated sludge had no effect on the rate at which the COD declined. The increased rate of nitrate removal with the addition of ethanol is of technical interest, as the volume of wastewater treated in a unit volume of filter medium for denitrification doubled with ethanol compared with sucrose at the same concentration.
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publishDate 2021
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spelling curtin-20.500.11937-826292021-03-19T03:15:01Z Dynamics of nitrate and nitrite in saturated sand filters with enhanced substrate conditions for denitrifying bacteria Al-Saedi, Rasha Smettem, Keith Stefanova, Katia Siddique, Kadambot HM Substrate conditions for denitrifying bacteria were enhanced by adding carbon sources to a laboratory-scale sand filter system. Temperature, oxidation–reduction potential, and hydrogen ion concentration were measured through the recirculation of nitrogen-dosed wastewater and carbon sources that were mixed to encourage microbial growth, with denitrifying bacteria identified by standard plate counts. Two different external carbon sources (sucrose and ethanol) were added, with and without activated sludge amendments. Nitrate, nitrite, and chemical oxygen demand (COD) concentrations were monitored relative to an untreated control and a treatment with activated sludge under an initial hydraulic loading rate of 0.508 m3 /m2 d and a hydraulic retention time of 2.5 h. Nitrate decay rates were only significantly enhanced for the ethanol treatment without addition of activated sludge. Nitrite initially accumulated when carbon sources were added, but no accumulation was evident by the end of the experiment after 150 min. COD declined when carbon sources were added, but activated sludge had no effect on the rate at which the COD declined. The increased rate of nitrate removal with the addition of ethanol is of technical interest, as the volume of wastewater treated in a unit volume of filter medium for denitrification doubled with ethanol compared with sucrose at the same concentration. 2021 Journal Article http://hdl.handle.net/20.500.11937/82629 10.5004/dwt.2021.26623 Desalination Publications fulltext
spellingShingle Al-Saedi, Rasha
Smettem, Keith
Stefanova, Katia
Siddique, Kadambot HM
Dynamics of nitrate and nitrite in saturated sand filters with enhanced substrate conditions for denitrifying bacteria
title Dynamics of nitrate and nitrite in saturated sand filters with enhanced substrate conditions for denitrifying bacteria
title_full Dynamics of nitrate and nitrite in saturated sand filters with enhanced substrate conditions for denitrifying bacteria
title_fullStr Dynamics of nitrate and nitrite in saturated sand filters with enhanced substrate conditions for denitrifying bacteria
title_full_unstemmed Dynamics of nitrate and nitrite in saturated sand filters with enhanced substrate conditions for denitrifying bacteria
title_short Dynamics of nitrate and nitrite in saturated sand filters with enhanced substrate conditions for denitrifying bacteria
title_sort dynamics of nitrate and nitrite in saturated sand filters with enhanced substrate conditions for denitrifying bacteria
url http://hdl.handle.net/20.500.11937/82629