Innovative vouchers 2024-2025
III. Biotechnologies and Environmental Protection
Institute of Chemistry of MSU
The project results will focus on the first-ever experimentation in the Republic of Moldova of the activity of a Specialized Department in assessing the impact of wastewater from the sewage system of human settlements and estimating the possibilities of functioning of a specific technological wastewater treatment system. A significant competitive advantage will be formed through collaboration between specialists from the research environment in wastewater treatment technologies and those in the field of design and commissioning of Biological Treatment Plants - BTP.
A modern laboratory will be organized and operated within the framework of LTD "Metiolis" for testing the main indices of wastewater and treated water. Thus, cases for human settlements with specific pollution problems will be investigated and the most optimal technological solutions for improvement will be proposed. The project will introduce state-of-the-art components involving moments of technological novelty. Thus, recommendations will be proposed for the technological lines of four BTP. For these Biological Wastewater Treatment Plants, optimization procedures in the operation of the BTP will be carried out to achieve an efficient separation of biogenic elements.
The results will be further designated by organizing seminars, workshops and other professional training activities for the BTP service staff, ensuring a continuous increase in the skills and abilities of the personnel involved in the management and operation of the treatment plants. These project results will contribute to the consolidation and expansion of the positive impact of the project in the community and to ensuring an efficient and sustainable management of the wastewater treatment infrastructure, both in the short and long term.
Summary of the activity and results obtained in 2024
In the Republic of Moldova, approximately 30 biological wastewater treatment plants (WWTP) are operational, of which only a few fully meet all quality standards. To address the critical issue of river pollution, a team of researchers from the Laboratory of Physico-Chemical Research and Analysis Methods at the Institute of Chemistry of the Moldova State University, in collaboration with the design and implementation team from S.R.L. ”METIOLIS”, a partner and co-funder, developed and implemented innovative solutions, including the establishment of a specialized department and the adoption of modern wastewater treatment technology.
The acquisition and equipping of a modern laboratory with HANNA equipment enabled the evaluation of the load of household wastewater in the localities of Cricova and Causeni. At the Cricova WWTP, the nitrification process achieves high efficiencies of 98.4–99.2%, while denitrification shows lower rates, below 50%, influenced by the organic carbon/total nitrogen ratio and the treated water temperature, optimal between 21.0 and 23.0°C. The high nitrate concentration generated during the nitrification stage accelerates denitrification in the secondary clarifier. To comply with environmental regulations requiring nitrogen removal levels of 70–80%, process optimization is recommended through the implementation of a biofilter with a developed specific surface area (150 m²/m³), a stripping system using intermittent intensive aeration, and a fine-turbulence post-aeration zone.
At WWTP Causeni, managed by I.M. “Apa-Canal” Causeni, an innovative biological treatment technology based on biofilm blocks was developed and introduced for the first time on an industrial scale. Microorganisms formed in these blocks range in size from 2 mm to 16 mm, with a density of up to 58 g/L, 20 times higher than that of activated sludge flocs in bioreactors. Nitrification at this plant achieves an efficiency of up to 99.3%, while denitrification varies between 19.9% and 91.1%, depending on the treated water temperature. Biofilm blocks enhance the denitrification process under continuous aeration conditions due to the active biological film.
To prevent and address accidental situations arising in the operation of WWTPs, physico-chemical parameters were analyzed, and specific intervention measures were developed. Additionally, a kinetic model based on ASM3 (Activated Sludge Model 3) was developed to estimate the pollutant removal potential. The obtained data form the basis of an operational guide designed for personnel without specific technical training, simplifying operations, optimizing plant activity, reducing energy consumption, and ensuring compliance with the quality standards of treated water.
- VISNEVSCHI, A., SPATARU, P., SPINU, O., POVAR, I. Original procedures of concentration of organic sediments with reduction of total nitrogen in WWTP. In: Book of Abstracts of the International Symposium “The Environment and the Industry”, SIMI 2024, September 19-20, Constanta, Romania, pp. 29-30. http://doi.org/10.21698/simi.2024.ab09. https://www.simiecoind.ro/wp-content/uploads/2024/09/9.pdf
- VIȘNEVSCHI, A. The anthropogenic impact on wastewater characteristics in the Republic of Moldova. In: The National Conference with International Participation «Natural sciences in the dialogue of generations», edition VII, September 12-13, 2024, Chisinau, Republic of Moldova, p. 119. ISBN 978-9975-62-756-6. http://agarm.md/wp-content/uploads/2024/09/Dialogul-generatiilor-ABSTRACT-BOOK_2024_F.pdf (comunicare orală)