Doctoral defence: Oleg Artemchuk “Autotrophic nitrogen removal processes for nutrient removal from sidestream and mainstream wastewater”

On 20 January at 14:15 Oleg Artemchuk will defend his doctoral thesis “Autotrophic nitrogen removal processes for nutrient removal from sidestream and mainstream wastewater” for obtaining the degree of Doctor of Philosophy (in Chemistry).

Supervisors:      
Research Fellow Ivar Zekker, University of Tartu
Professor Toomas Tenno, University of Tartu

Opponent:
Professor Marina Valentukeviciene, Vilnius Gediminas Technical University (Lithuania)

Summary
In the recent decades, the production of waste has increased, which today threatens the quality of environment and poses risks to human health. One of the main problems for today’s society is limited access to high-quality drinking and household water.
The introduction of several biogas plants involves the conversion of organic carbon to biogas and the presence of elevated nitrogen compounds in wastewater. Treatment of such wastewater streams by traditional methods (nitrification-denitrification) is costly and requires addition of organic carbon back into the treatment process (often in the form of methanol).
Among the wastewater treatment technologies, the anaerobic ammonium oxidation (anammox) process has mostly been incorporated into the autotrophic nitrogen removal for low organic carbon wastewater.
The mainstream wastewater can be called domestic wastewater, and the side stream – reject water. The latter is formed after residual sludge fermentation and centrifugation and separation of excess sludge from wastewater. We attempted to include the anammox process in both: side- and mainstream treatment using moving bed biofilm reactor (MBBR) and sequence batch reactor (SBR) technologies. The wastewater flow was switched between side stream (reject water at >22°C) and mainstream (municipal wastewater at 16.5°C) after every 8 weeks, so that the anammox biomass activity and biomass growth could benefit from sidestream conditions. Nitrogen removal efficiencies of over 80% and 40% and were achieved during sidestream and mainstream operation, respectively.
The process of anammox was studied by controlling the rate of reduction of redox potential (ORP) in the anammox SBR. SBR was inoculated and fed with highly concentrated, nitrogen-rich effluent from a biogas plant. Nitrogen removal efficiency of 95% was achieved.
Launching of the anammox process was tested from scratch in a 20-liter SBR inoculated with a mixture of aerobic and anaerobic sludge at 30 ± 0.5 °C. Sustaining the optimal salinity level increased the activity of the anammox process and the rate of nitrogen removal.
Biological removal of nutrients from wastewater was achieved to an acceptable level, which is necessary for protection of water resources and avoid eutrophication.

Defence can be also followed in MS Teams.