The IDRO.SMART project proposes circular economy and environmental sustainability virtuous model in the urban wastewater purification sector, based on ndustry 4.0 concept. The specific objective of the proposal is the innovative management of the treatment chain by integrating advanced purification solutions with the resource recovery from produced sludge.
The project will be partially developed through UNALAB, a joint University-Company laboratory, founded by Publiacqua S.p.A., leader of the proposal, together with the University of Florence. The project will set the basis for overcoming the well-known issues connected to the disposal of sludge, such as the increasing transport/disposal costs and the environmental impact associated with the sludge exploitation in agriculture, transforming the traditional treatment chain into an integrated and sustainable cycle. In fact, the solution integrates an advanced water purification technology, which involves the use of aerobic granular biomass (AGS) to replace conventional activated sludge treatments, with a slow pyrolysis process of the dried sludge. AGS are characterized by an excellent sedimentation speed, higher conversion rates of pollutants (C, N, P) per volume unit and the possibility of operating at high concentrations with a resulting reduction of sludge production (-60%), reduction of land occupation (-40%), of energy costs (-25%) and the possibility of recovering phosphorus and biopolymers, which can be reused in numerous production sectors.
The use of Internet of Things communication technologies will allow to implement remote monitoring and control solutions, essential for the management of the proposed technological solutions.
The process waste, together with the sludge produced by purification plants currently managed by Publiacqua S.p.A., will be dried and then processed through an innovative thermo-chemical treatment system aimed at the combined recovery of phosphorus, nutrients and carbon. The process, developed by RE-CORD, consists of a first phase of slow pyrolysis, where the sludge is converted into gas that can be used directly as fuel, acetic acid deriving from the condensation of organic compounds, and biochar, a hydrophobic material with a high concentration of carbon and inorganic compounds such as phosphorus, calcium, potassium.
After that the second phase of the process involves the extraction of the inorganic compounds from the biochar through a chemical processing that allows to obtain two different products: a fertilizing compound rich in macro and micro nutrients (P, N, Mg, Ca, K , Fe) that can be used in agriculture and a high carbon content bichar that can be used as a substitute for fossil coal in the production of activated carbon and in the steel industry.
The technologies proposed, managed and integrated with industrial internet solutions, will transform the current destination of sludge as a waste, into "end of waste" products, with a reduction in the overall costs and the environmental impact. The integrated management system will make use of advanced tools such as LCA to assess the environmental sustainability and the replicability of the treatment processes developed and of the resource recovery/enhancement flows.
This project has received funding from POR FESR TOSCANA 2014 – 2020, AZIONE 1.1.5 sub A1) – FSC 2014-2020 (ex Del.CIPE 40/2020) Project “Aiuti agli investimenti R&S delle imprese” CUP: 3647.04032020.157000040