Diversity of ammonia oxidising microorganisms in constructed wetlands fed with landfill leachate

Nice, Kirsty (2019) Diversity of ammonia oxidising microorganisms in constructed wetlands fed with landfill leachate. Masters thesis, University of East Anglia.

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Every year five million tonnes of ammonia-containing landfill leachate is generated from closed landfills in England. Ammonia is toxic to the environment and requires costly and environmentally unsustainable treatment at municipal wastewater treatment plants. Norfolk County Council are pursuing an alternative, more cost effective and environmentally friendly leachate treatment using the microbially driven anammox (anaerobic ammonia oxidation) reaction in vertical flow constructed wetlands trials. Conversion rates of 70-100% NH3 has typically been observed but the underpinning microbiology remains unknown, severely restricting process optimisation. The aim of this MSc thesis was to develop the molecular tools to determine if anammox microorganisms and other essential nitrogen-cycling microorganisms were present and to investigate their diversity. It was hypothesised that such major players in NH3 transformation would be detected within the constructed wetland trials. It was further hypothesised that differences would be observed in the nitrogen-cycling community between unsaturated and saturated layers of the wetlands due to moisture content disparity and between unvegetated and vegetated wetlands. The trials tested were an unvegetated wetland and a vegetated wetland planted with the common reed (Phragmites australis), often found in the salt marsh environment which these trials replicate. Primers were optimised for the annamox functional marker genes hydrazine synthase (hzsA) and hydrazine oxidoreductase (hzo). Additionally, aerobic ammonia oxidising bacteria

(AOB) and archaea (AOA), which are important in supplying anammox with nitrite, were studied by targeting the ammonia monooxygenase (amoA). Anammox bacteria, AOB and AOA were detected in both constructed wetland trials tested. The diversity of anammox bacteria, AOB and AOA was surprisingly consistent across the unsaturated and saturated regions of the wetlands and the presence of Phragmites reeds had little effect on anammox diversity. Detection of anammox microorganisms by PCR in these trials supports future use of this approach which has great scope for optimisation and scale-up.

Item Type: Thesis (Masters)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Chris White
Date Deposited: 15 Apr 2021 09:51
Last Modified: 15 Apr 2021 09:51
URI: https://ueaeprints.uea.ac.uk/id/eprint/79781

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