Water treatment and re-use within

peroxide production units



Background and state of the art

The Rosignano Solvay industrial site is one of the oldest and largest in Italy. It produces sodium carbonate, sodium bicarbonate (also for pharmaceutical use), calcium chloride, chlorine, hydrochloric acid, chloromethane, plastic materials, peracetic acid and hydrogen peroxide. In order to deliver more sustainable water management, Consorzio ARETUSA was established in 2001 as PPP among water utility (ASA Livorno), industry (Solvay Chimica Italia) and tech provider (Termomeccanica). Thanks to ARETUSA, since more than 15 years the Solvay chemical plant is implementing a utility-industry (public-private) symbiosis system for optimising the regional water cycle, by reusing about 3 million cubic meters per year of urban wastewater treated in the ARETUSA reclamation plant. The existing Waste Water Reuse Plant (WWRP) contains flocculation, sedimentation, filtration, activated carbon filter (GAC), and UV disinfection.

Actions and expected results

The pilot plant will be integrating (1) chemical pre-treatment for pH control, (2) filtration in an Iron Oxide-Coated Gravel/Sand Fixed Bed Column or Iron oxide (geothide) filled bed to remove H2O2 and metals, (3) high-loaded biological denitrification in a membrane bioreactor. The effluent from the pilot plant will be tested for impact and tertiary treatment within processes operated in ARETUSA reclamation plant to increase the water to be re-used in Solvay industrial site.

Digital solutions will be applied for:

  • Process control in the WAPERUSE processes

  • the internal re-use of cooling tower blowdown streams and;
  • the treatment and direct reuse of slightly polluted process water and dilution steam blowdown streams.

Digitalization of the water reuse scheme will include the design for full digital smart control and integration in the existing water grid for current operations.

Partners involved