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ECOLORO: Reuse of Waste Water from the Textile Industry

Periodic Reporting for period 2 - ECWRTI (ECOLORO: Reuse of Waste Water from the Textile Industry)

Reporting period: 2016-12-01 to 2019-05-31

Global freshwater availability is under stress and there is a need for future-proofing the industry with respect to water usage. ECWRTI Report on wastewater handling in the textile industry in EU shows that dyeing and printing processes at textile industry require considerable amounts of fresh water and produce large and often polluted wastewater streams. This wastewater, usually contains a mix of colorants, chemicals, salts, metals and other organic and inorganic compounds. The wastewater is treated on-site by the textile company and then discharged to the environment, or it is supplied to the municipal wastewater treatment plant (with or without a pre-treatment by the company).
EColoRO concept offers a solution to treat the wastewater of textile industry with a minimal use of chemicals and energy. Nearly 70% of the wastewater can be reused in the textile manufacturing process, what reduces the water need by nearly 60%. The core of the concept, Electro Coagulation, is based upon the release of Fe3+ ions from an iron source by means of a low voltage electrolytic action. The ions coagulate and flocculate with impurities present in the water so that these can be removed by means of sedimentation or flotation. Subsequently, the water is passed through ultrafiltration and reverse osmosis membranes, after which it can be re-used. Pollutants end up in the sludge (from flocculation) and the concentrated brine (from membrane filtration), which are the waste streams of the ECOLORO concept. As a result, EColoRO creates new approaches for water treatment and management within a factory, allowing on re-use wastewater and avoiding discharging pollutants with the wastewater. Valorisation of sludge and recycling of brine could contribute to further pollution reduction, these studies were part of the ECWRTI project.
The EColoRO concept was tested at pilot scale (up to 2m3/hr) at four sites:
•Utexbel Snoecklaan (BE)-Advanced textiles for special applications
•Utexbel Ninovestraat (BE)-Yarn dying mill
•Tintoria Pavese (IT)-Cellulosic linings and cotton linings
•Setex (DE)-Fashion fabrics and home textiles

Scale-up towards demonstration plant scale, foreseen at the Utexbel site, was not further pursued due to unforeseen delays in granting of permits and additional costs related to the complexity of the wastewater. In addition, during the project the business case diluted because of tax reduction on discharge. Scale-up foreseen at Tintoria Pavese was not further pursued as the concentration of brine components exceeded the local discharge limits.
Additional studies were performed on valorisation of the sludge and concentration of the brine produced as a result of the EColoRO treatment. ECWRTI entailed a cross-market analysis, a techno-economic feasibility study, an analysis of wastewater handling, an LCA analysis and an EU wide legal scan. The project has identified the relevant factors determining the technological feasibility at individual sites, also used to create the courseware material for industry and students.

The EColoRO-technology performed well at four pilot sites, achieving water 70% recovery rates. As a result of the pilot experiments, modifications were proposed to optimize the EColoRO process. Energy consumption strongly depended on the amount of oxidizable pollutants (COD) in the wastewater and the conductivity of the water, and at higher temperatures the floc formation can became more difficult.
The further treatment of brine was evaluated for three technologies (Galicos, DC-MD and air-gap MD), the Galicos system tests led to a bench scale process in a stable operation up to high concentration factors. Adsorbent in biogas installations or in filters for metals or phosphorous were identified as main possible valorization options for sudge.

Understanding the business case
The costs of application of total water re-use have to be evaluated case by case. The operating expenditures (OPEX) are determined by the type of the freshwater source, the processed volume of water, the pollution load of the wastewater and the required amount of energy for the EColoRO process and the discharge taxes. The combination of these factors does not always turn out positive; in many situations the cost of water, energy and/or discharge of waste weakens the business case. These costs are mainly dependent on local governmental policy, while on the other hand costs-cutting pressure on textile manufactures depends by buyers demands, external factors and international competitiveness.

Regulatory aspects
Obtaining permits for the discharge of sludge and brine is a difficult process and requires discussions with the local authorities. In one case, brine discharge with increased concentrations of certain pollutants can be accepted when applying extended water reuse, in another, increased concentrations of certain pollutants can result in adverse ecotoxic effects and hence brine cannot be discharged. The chemical sludge resulting from the electrocoagulation process poses another obstacle since it is considered hazardous waste and has to be transported and disposed of accordingly. To these regards, ECWRTI has been connected to the BREF revision process to stimulate enabling factors, in terms of emission requirements.
EColoRO concept for re-use of water is proved to be broadly applicable in the textile industry. EColoRO concept is linked to the EU policies which can encourage its implementation. On the individual site level the factors determining the technological feasibility were defined. Implementation, however, is impeded by tailored-made costs-benefit analysis, operational expenses, as well as costs pressure and regulatory requirements that both heavily depend on governmental policies . There is a clear interest of textile companies in adopting water re-use technologies. In particular, experienced or forecasted water shortages are a 'natural' driver for change. A mind-set of appreciation of water as a scarce good in general would be a further motivation for implementing water conservation strategies. The latter can be encouraged by providing financial instruments. In addition, it is advised to organise new national or regional workshops in combination with SDG 12 events.
Whether a business case can be found for the application of the EColoRO water re-use concept depends on water and energy pricing and discharge policies (regarding cost as well as permits). A legislative obstacle for water re-use is when brine cannot always be discharged due to elevated concentrations of certain pollutants and needs to be treated further. This hampers the business case.
Finally, in the perspective of a circular economy, the brine and sludge could be further valorised. In some cases, REACH legislation applies on the recovered substances and thus products would need to be registered. This complex procedure may hamper recovery and recycling from wastewater and as such hamper the total circular use of water.
Policy measures able to balance the additional costs for evaluating and testing innovative water-treatment technologies such as the EColoRo concept would significantly remove barriers. Measures supporting investment may complement and support broad adoption in the sector.
Crucial obstacles and possible solutions for feasible recycling and recovery need to be taken into account if policy is to create a level playing field and enable circular use of water.