Doctoral dissertation

Biological energy recovery from dairy wastewaters during low temperature anaerobic treatment

Rising fuel costs along with incentives favoring renewable energy market are pushing the global market towards green energy and circularity of water resources. In 2018, the global milk production reached approximately 8.4 trillion litres, wherein each 1 litre of the milk processed may result in 0.5 to 10 litres of wastewater. Anaerobic digestion offers a valuable resource recovery option for the treatment of dairy wastewaters due to the production of biogas from the treatment process.

However, an efficient growth of anaerobic consortium is crucial for the successful anaerobic treatment, for which mesophilic (30-35°C) or thermophilic (48-55°C) conditions are optimal. Heating the dairy wastewater to typical mesophilic conditions increases the operational costs of the treatment process, especially in temperate regions; and treatment closer to discharge temperatures is sought.

At low temperatures, there is a lack of knowledge on continuous anaerobic treatment of dairy wastewaters containing of the fats, oil, grease and long chain fatty acids (LCFA). In her doctoral dissertation, MSc Suniti Singh focused on the anaerobic treatment of LCFA-rich wastewater at discharge temperatures for biomethane production. Singh demonstrated successfully continuous anaerobic treatment in different anaerobic reactor types and revealed the microbial communities using high-throughput amplicon sequencing.   The results contribute towards developing low-temperature anaerobic treatment applications for dairy wastewaters.

“It was very exciting to design reactors for the treatment of LCFA-rich wastewaters, and to achieve excellent results in terms of methane production from wastewaters even at high hydraulic flows at 20ºC, something that was deemed inconceivable when I started this doctoral thesis work three years ago. It was a steep learning curve working on this topic but was undeniably fascinating.” Singh mentions.

Public defense of a doctoral dissertation on Wednesday, 11th of December
MSc Suniti Singh’s dissertation in the field of environmental engineering titled High rate anaerobic treatment of LCFA-containing wastewater at low temperature will be publicly examined in Université Paris Est (address: Marne-la-Vallée, Paris, France) on Wednesday, 11th of December 2019 at 11h00. The opponents will be Prof. Alla Nozhevnikova from the Russian Academy of Sciences (Russia), Prof. Charles Banks from the University of Southampton (United Kingdom), and Assoc. Prof. Marta Carballa from the Universidade de Santiago de Compostela (Spain). Prof. Giovanni Esposito from the Department of Civil and Mechanical Engineering at the University of Cassino and Southern Lazio (Italy) will act as Custos.

Suniti Singh’s doctoral research has been conducted in the framework of the Advanced Biological Waste to Energy Technologies (ABWET) Innovative Training Network (ITN) European Joint Degree Programme. ABWET has four partner organizations: the University of Cassino and Southern Lazio (Italy, coordinator), Université Paris-Est (France), IHE Delft (the Netherlands) and Tampere University (Finland). The Examination Committee of Suniti Singh’s doctoral dissertation includes one representative from each partner organization.

Suniti Singh hails from India and performed her thesis work in the Faculty of Engineering and Natural Sciences at Tampere University (Finland), National University of Ireland Galway (Ireland) and IHE Delft Institute for Water Education Delft (the Netherlands).

The dissertation is available in the faculty of Engineering and Natural Sciences (Konetalo building K2222A) at Tampere University and by request from the address: suvi.ikonen@tuni.fi