Closed-loop wAter Systems in textile industrial distriCts: multimodal orchestrAteD rEmoval of emerging pollutants from textile wastewater

Emerging contaminants is a very broad category of chemical substances , including medicines, personal care, household cleaning products, and agricultural products. They are widely present in aquatic environments and include both new chemicals, and substances and materials that have long been present in the environment, but whose risk is currently under discussion. The release of these substances into the environment occurs mainly through municipal and industrial wastewater discharge.  

The LIFE CASCADE project addresses the two most critical categories of emerging pollutants for the textile sector: poly- and per-fluorinated compounds (PFAS) and microplastics.  

PFAS have been used for a wide range of functional applications in the textiles, upholstery, leather, apparel and carpet industries. PFAS used in apparel products are estimated at between 45,000-80,000 tonnes / year in the EU, and textile applications can account for an estimated 35% of demand for fluorotelomers. It is also estimated that, among 15 PFAS researched, some 27-56% of the PFAS from the fashion industry is released to the environment. 

The EU Biodiversity Strategy for 2030 identifies microplastics pollution as one of the five main direct causes of biodiversity loss. According to the European Chemicals Agency (ECHA), in Europe, every year, products containing 145,000 tonnes of microplastic fibres are dispersed in the marine environment. Fibrous microplastics can be generated at any point during the lifetime of synthetic textiles i.e., during production, use (wearing, washing, maintenance etc.) and disposal. 

Despite the presence of seven large wastewater treatment plants (WWTPs), both substances have been detected in the industrial wastewater discharged in Como.  This is one of the most important textile districts in Europe, where mainly small- and medium-sized textile companies are involved in finishing processes (printing, dyeing and finishing), and process various kinds of fibres.  

The LIFE CASCADE project aims to develop, test and demonstrate analytical procedures and wastewater treatment technologies to detect and remove the two most critical categories of emerging micropollutants for the textile sector: PFAS and microplastics.  

The project objectives are to develop: 

Procedures and protocols for contaminant analysis (detect); and  

Technologies for the removal of pollutants from wastewater for both factory and centralised wastewater plant levels (remove).  

The project will implement demonstration pilots of the innovative technologies for the removal of the two contaminants.  

For both detection and removal, a distinction will be made between those relating to PFAS and those relating to microplastics, namely: 

Detect: Analytical protocols for wastewater test – Focus on PFAS 

Detect: Analytical protocols for wastewater test – Focus on Total Organic Fluorine (TOF) 

Detect: Analytical protocols for wastewater test – Focus on microplastics 

Remove: technologies to eliminate contaminants – Factory level, Focus on PFAS 

Remove: technologies to eliminate contaminants – WWTP level, Focus on PFAS 

Remove: technologies to eliminate contaminants – Factory and WWTP levels, Focus on microplastics. 

The expected results of the project are: 

Removal of PFAS and microplastics: 

85% PFAS removed from treated wastewater flows at the factory level 

80% PFAS removed from treated wastewater flows at the WWTP level 

80% microplastics removed from treated wastewater flows 

65% microplastics removed from treated wastewater flows separately from other pollutants 

Environmental impacts:  

Overall removal of PFAS from discharged wastewater into the surface water network: 0.15% at the project’s end (corresponding to a reduction of 69 g/y) and 20% 3 years after the project’s end (corresponding to a reduction of 9,281 g/y). 

Overall removal of microplastics from discharged wastewater into the surface water network: 0.65% at the project’s end (corresponding to a reduction of 330 kg/y) and 11% 3 years after the project (corresponding to a reduction of 5,640 kg/y). 

Water quality: reduction in length of surface water bodies whose ecological status is affected: 1 km at the end and 102 km 3 years after the project. 

Water efficiency: the textile companies in the Como district are 50% supplied by an industrial aqueduct (8.5 million m3/year). The volume treated at the end of the project is 10,000 m3/year, but 3 years after the end of the project it is assumed that the industrial aqueduct will be supplied with 25% of the wastewater treated by two WWTPs. 

Soil local contamination: 60% of the sludge produced (6,500 tonnes per year of dry matter) by the seven centralised WWTPs in the Como textile district is disposed of in agriculture, over an area of ca. 16.25 km2. At the end of the project the estimated reduction of the area affected by local contamination is 0.046 km2, while after 3 years after the end of the project, the land area with soil quality issues could be reduced by 2.62 km2.