TREATMENT OF LIQUID WASTES BY UASB TECHNOLOGY: PROCESSES, SUBSTRATES AND ENERGY RECOVERY
The PhD main activity will be the study and development of a UASB (Upflow Anaerobic Sludge Blanket) treatment for various liquid wastes amenable to be transformed in and biological anaerobic environment. The work will be performed by a collaboration between the Department of Chemistry, Physics and Environment of the University of Udine and the Carniacque Spa company.
A series of experimental and “on the field” applications are forecasted to seek new solutions to optimize UASB process, both by waste matrixes pretreatment and upgrading process.
The aim of the work is to deep topics bound to the UASB use on liquid wastes treatment with energy recovery potential.
The PhD work will lead to the design of a new section in the Tolmezzo Wastewater treatment plant, starting from the characterization of the matrices, the simulation and the pilot testing of the UASB process in an actual case study.
Progetto Regionale LR 47/78 / PAR-FSC 2007-2013 - Linea Azione 3.1.1 (scorrimento graduatoria 2014-17) con Carniacque SPA
The research activity set up with BMP trials on various matrices and the construction of the plant was continued through UASB pilot tests, which were carried out on various matrices (cheese dairy, paper mill condensate, percolated by FORSU), with monitoring continuous implantation and chemical-physical laboratory analysis. In particular, the pH of the food reflux, the redox potential, the flow rate, the inlet and output COD, and the process temperature were monitored. Evaluations were made of process efficiency and biogas production. Several operating conditions have been tested, in terms of HRT, range and OLR. Odor-sampling was carried out to assess the presence of odors in both biogas and in the effluent from the pilot plant. In order to complete the matrix characterization, precise analyzes were made on volatile fatty acids, TKN and fats / oils.
As far as the paper-based condensate test is concerned, the UASB operating conditions of the UASB system have been replicated on a real scale, both in terms of hydraulic retention time and recirculation ratio, to have reliable indications for the scale-up of the process; a sulfur monitoring (both inorganic and organic) was carried out in such a way as to understand the distribution of this compound between gaseous phase and liquid phase.
Additional laboratory-scale tests were carried out with the AMPTS instrument to have a greater spectrum of data, in particular on dairy whey, even with sonic pre-treatment using different inoculum / substrate ratios.
The process modeling of a wastewater treatment plant, in particular with regard to anaerobic processes (ADM1 model), has been studied in order to carry out some simulations on the tests carried out using the GPS-X software.
A further step in the work was the study of the correlation between redox potential (ORP) and dissolved oxygen (DO) in the oxidation tank to find a correlation between these parameters useful to reduce the process set-point and thus energy consumption ; it is expected that some tests will be carried out through an aerobic pilot plant at Tolmezzo's WWTP.
Pilota UASB realizzato per la sperimentazione (Grazie, Marco e Luca et al. !)
Matia con il suo UASB (work in progress by CAFC Spa)
Matia al "European Biogas Association", Anversa 2018.
M. Mainardis, G. Rossi, V. Cabbai, D. Goi, “Characterization of high-loaded organic substrates and suitability as a potential feed for high-velocity anaerobic UASB reactors”. In: M.R. Boni, P. Sirini, A. Chiavola, A. Polettini, R. Pomi, P. Viotti, A. Rossi. Book of Abstracts, (2016), X International Symposium on Sanitary and Environmental Engineering, SIDISA 2016. Rome, 19-23/06/2016, P/20, ISBN: 978-88-496-391-1.
M. Mainardis, G. Zannier, M. Mion, D. Goi, “Energetic Valorization of Cheese Whey using UASB Technology: a casestudy”. Communications in Agricultural and Applied Biological Sciences, Ghent University, (2017), 82 (4).
M. Mainardis, G. Zannier, M. Mion, D. Goi, “UASB anaerobic treatment of liquid substrates: A case study in FriuliVenezia Giulia region”, 9th Eastern European Young Water Professionals Conference, Book of Abstracts, ISBN 978- 963-313-256-2, 24-27 May 2017.
M. Mainardis, V. Cabbai, G. Zannier, D. Visintini, D. Goi, “Characterization and BMP tests of liquid substrates for highrate anaerobic digestion”. Chem. Biochem. Eng. Q., (2017), 31(4).