The research program aims to experiment a new plant technology to value organic materials from urban wastewater depuration and from co-digestion of sewage sludge and organic fraction of municipal solid waste. Disposal of these materials represents a cost for the community, instead this treatment could produce a good quality compost that could be used as an organic free fertilizer of green public areas. This technology is applicable to small scale area adjusting small wastewater treatment plants to recycle and value sewage sludge and digestate. The research program aims to adjust two sewage sludge drying beds inside the plant to realize an aerated static pile composting. This project choice is justified by the simple technology in comparison with other market solutions. An investigation was set up to control the starting materials (sewage sludge or digestate, pruning residues from gardens and green public areas, organic fraction of municipal solid waste) and final product quality to monitor the process and to increase its performance. The project aims to obtain a good quality compost complying with Italian regulation about composting (D.lgs. 99/92 e D.Lgs. 75/2010).
The research project aims also to develop and test an innovative and efficient technology to reduce the soil nitrogen flux from the application of slurry and waste from anaerobic digestion plants. The plan includes a nitrogen removal from slurry by ammonia stripping and produces a waste or a digestate depleted in nitrogen (NH3-free); in particular, several bench top tests with monitoring and mass balances are planned, with sizing of collection systems, control of the final product (slurry and ammonia sulfate) and evaluation of odour emissions. Results of this part of the project could help farmers, with or without an anaerobic digestion plant, reduce nitrogen content in slurries; in fact, these livestock farms are located in nitrate vulnerable zones and are expansion limited by restricted available land for spreading slurry. A waste NH3-free could be used entirely on total farm area reducing costs and environmental impact of transport. Moreover the conversion of stripped ammonia in ammonium sulfate could allow market placement as mineral fertilizer: its high nitrogen content makes also long distance transport more convenient. In this way the research project could solve the problem of slurry employ in close production proximity.
- C.B. Rizzardini, L. Catalano,M. Contin, D. Goi, M. De Nobili, “Effetti del Mercurio sulla metanogenesi in sedimenti, suoli e fanghi di depurazione”, Atti del XI Congresso Nazionale di Chimica dell’Ambiente e dei Beni Culturali, Muggia (TS) 16- 20 Giugno 2008, ISBN 978-88-8303-230-1.
- C.B. Rizzardini, D. Goi, “European Directives and Italian Regulation on Sludge from Municipal Wastewater Treatment Plants: Current Status and Future Prospective”. The Open Waste Management Journal, 2009, 2, 17-26.
- C.B. Rizzardini, M. Contin, M. De Nobili, A. Patriarca, D. Goi, “Small scale co-composting plants to recycle sewage sludge and green waste”, Proceedings of Waste-to-Resources 2009, III International Symposium MBT amd MRF, Mechanical biological waste treatment and material recovery facilities, Matthias Kuehle-Weidemeier Ed., 12-15 Mai 2009, Hanover, Germany, pp 560-564, (2009), ISBN: 978-3-86727-956-7.
- C.B. Rizzardini, D. Goi, “ Recuperabilità dei fanghi di depurazione”, IA-Ingegneria Ambientale, (2010), XXXIX (7-8):380- 383.
- C. B. Rizzardini, M. Contin, M. De Nobili, D. Goi, “Il recupero dei fanghi di depurazione prodotti da impianti di trattamento delle acque reflue”, Rassegna Tecnica del FVG, (2010), 5/2010: 36-39.
- C.B. Rizzardini, M. Contin, M. De Nobili, D. Goi, “Sewage sludge quality from small wastewater treatment plants”. Proceedings of the ICE - Waste and Resource Management (2012), 165: 67-78, ISSN: 1747-6526, DOI: 10.1680/warm.2012.165.2.67.
- C.B. Rizzardini, D. Goi “Pollution concerns on land use of sewage sludge from municipal wastewater treatment plants”. In: L. Bonomo, R. Canziani, F. Malpei, M. Grosso, S. Saponaro. Book of Abstracts, (2012) SIDISA 2012. Milano, 26- 29/06/2012, vol. ID: 876, Milano:L. Bonomo, ISBN: 978-88-903557-2-1.
- L. Piani, C. B. Rizzardini, A. Papo, Goi D. “Rheology Measurements for Online Monitoring of Solids in Activated Sludge Reactors of Municipal Wastewater Treatment Plant”. The Scientific World Journal, Volume 2014, Article ID 590961, 6 pages, Hindawi Publishing Corporation, http://dx.doi.org/10.1155/2014/590961.
- C. B. Rizzardini, D. Goi, “Sustainability of Domestic Sewage Sludge Disposal” Sustainability (2014), 6(5): 2424-2434, http://dx.doi.org/10.3390/su6052424.