• Obtain a versatile water recycling scheme to treat different wastewater streams generated in petrochemical processes
  • Demonstrate the feasibility and promote the implementation of an innovative water reuse scheme in petrochemical industries
  • Disseminate the obtained results and transfer the knowledge acquired regarding the innovative water recycling scheme
  • Quantify and disseminate the environmental benefits and the economic impact of the innovative water recycling scheme compared to the currently applied water management strategies.
  • Develop a decision support tool to predict the environmental and economic benefits of the new technology.

Technical Solution

REWATCH proposes an on-site reuse scheme including five different technologies to constitute a completely new treatment scheme in the petrochemical industry: physicochemical pretreatment, moving bed biofilm reactor (MBBR), ultrafiltration (UF), reverse osmosis (RO) and water deionization using ion exchange resins (IER). This treatment scheme is highly versatile because it is designed in such a way that the wastewater may enter at any point of the treatment train depending on its initial composition and reclaimed water may also exit after each treatment step depending on the obtained water quality.

Treatment step

Treatment principle

Target water constituents removal


It is a high rate compact water clarification process in which water is flocculated with microsand, which enhances the formation of robust flocks and acts as ballast, significantly increasing their settling velocity.

Total organic carbon (using PAC, Actiflo® Carb version), chemical oxygen demand, turbidity and suspended solids

AnoxKaldnes® MBBR

This biological process combines the best features of the activated sludge process with the features of biofilters. Bacteria responsible for the biological degradation are attached to specially designed plastic carriers which remain suspended in the reactor. The carriers are designed to provide a large protected surface area for the biofilm to grow and optimal conditions for the bacteria culture.

Total organic carbon, chemical oxygen demand, biological oxygen demand, nitrogen


Membrane filtration process with pore sizes of the membrane in the range of 2-100 nm. Rejection is determined mainly by the size and shape of the solutes relative to the pore size in the membrane and where permeability is directly proportional to the applied pressure. REWATCH optimizes the membrane filtration cycles with the implementation of new fouling control strategies.

Turbidity, suspended solids, colloids, microbiological load


Membrane filtration process with pores smaller than 0.5 nm. REWATCH is using last-generation RO membranes manufactured by Dow Chemical Ibérica.

Dissolved organic matter, dissolved multivalent and monovalent anions and cations, silica, iron, copper.


Ion exchange resins are polymers that are capable of exchanging (harmless) ions with ions in a solution that are passing through them. REWATCH is using resins developed by Dow Chemical Ibérica.

Total dissolved solids, multivalent and monovalent anions and cations, silica, iron, copper.

Demonstration site

The demonstration site of REWATCH is located in DOW Chemical Ibérica – North Petrochemical ChemMed Cluster located in Tarragona, Catalonia region, Spain.

ChemMed Tarragona is an industrial, logistical, academic and scientific chemical cluster located in the greater Tarragona area in northeast Spain, by the Mediterranean Sea.

ChemMed Tarragona encompasses:


  • More than a hundred chemical companies of all sizes. Production companies and service companies. Production includes petrochemicals, polyolefins, plastics, organic chemical products and industrial products as well as specialty chemicals and fine chemicals, thus representing the classic value-creation chain.
  • First-rate cargo port. Leading port for chemical industry, ensuring the import of raw materials and competitive feedstock and is a means to exporting products manufactured. Efficient logistics facilities.
  • Pooled infrastructure and services
  • Two combined cycle plants totaling 820MW power for electricity, steam, nitrogen, hydrogen, compressed air and demineralized water supply to companies within the cluster.
  • Reclaimed water supply. A source of supply reaching up to 20 hm3/year.
  • Pooled underwater sewage outlet pipe.
  • Pipeline infrastructure for transportation and exchange of materials connecting all sites and companies among them and with the Tarragona harbor.
  • Three pooled fire stations

Work plan

Expected outcomes

Reduction in water abstraction of European petrochemical plants (i.e. steam crackers, etc.)

Decrease in wastewater discharge

Reduction in total energy consumption related to the water cycle

Climate change reduction