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A plant will be designed to treat up to 4000 tons of sewage sludge to be connected to Cassano d’Adda municipal plant, managed by the CAP Holding Group of Milan, how is better specified in B5.

For this installation we will contact the Public Administration to discuss the administrative aspects. However, the installation of the demonstration system is not subject to the granting of a waste treatment authorization, since the sludge that will be treated is not considered waste because the treatment is performed within the purification cycle, as required by Article 127 of the Legislative Decree 152/2006. This aspect will be clarified later in Form B5 – constrains and risks.

Project and realization of the demonstration plant will be carried out by SYNGEN s.r.l., while its placement and connection with the existing purifier will be carried out by CAP Holding S.p.A.

A continuous working plant able to treat the sludge according the following sequence of phases will be designed and built:

• PHASE A – Conditioning of the biological starting material with addition of calcium ions donor reactives.
• PHASE B – Insertion of biomass into the high-pressure pump (working pressure 200 bar).
• PHASE C – Decomposition of the organic substances at the working conditions of 200 bar and 360 °C with a reaction time of 15 minutes. The organic substance is decomposed into four products: water, gas, oil, tar.
• PHASE D – Extraction of treated material while maintaining the working pressure inside the reactor using a lamination valve.

Once the system is activated, the operation will be continuous (apart from the stops for maintenance) and the products will be characterized in order to check the compliance of the chemical and physical characteristics for the purpose for which they are intended. The functional check will be carried out by AGROI s.r.l. and CAP Holding S.p.A., while control analyzes by UNIPV.

Commercial valorisation of the products obtained from the sludge by HTL process will include analyses and tests related to the specific fields of use.

Bio-Oil: verification of the percentage to be mixed with bitumen to create road surfaces; determination of the lower calorific value for use as fuel.

Mineral residue: application of the “Alkaline Activation” technology for the production of some different building materials (binders).

Phosphorus: check the Cadmium concentration and the solubility of phosphorus salts, important for agricultural use.

This step will be developed by UNIPV and IETcc-CSIC. Implementation of bio – oil in asphalts will be carried out by Impresa Caffù.

The environmental and social impacts generated by the installation of the plant, as well as the economic one, will be monitored by CAP Holding, as technical manager of the integrated water cycle and owner of the purifier where the HTL system will be installed.

A communication action will be carried out to make stakeholders aware of the existence of the initiative and its results in the environmental and economic field. The plant itself will represent a commercial showcase for institutions interested in replicating the plant on its own purifiers. Meetings and workshops will be organized by UNIPV under the patronage of Province of Pavia, Lombardy Region and Environmental Ministry, as to date, the regulation of the recovery or disposal of sludge is responsibility of these local authorities.