When I asked this question to a friend who works in the CSR department of a global brand, he tapped his cigarette slowly in the ash tray and said "Mon cheri, we all know cigarettes are injurious to health. But have they been eliminated from this world?"
While this comment should be taken with a pinch of salt (since banning cigarettes is very different from banning APEOs), it is definitely indicative of the huge challenge to eliminate APEOs 'across all pathways within the supply chains of all products' by 2020 – the target date set by several global apparel and footwear brands committed to Detox.
This is because, unlike most other Restricted Substances Groups, APEOs cannot be pinned down to one particular source and are ubiquitous across all stages of the textile production chain.
Restrictions on the use of Nonylphenol Ethoxylates (NPE) for use in textile production was implemented in the EU in 2005 (Directive 2003/53/EC; REACH Regulation, Annex XVII (46)). This requires that "NP/NPE shall not be placed on the market or used as a substance or constituent of mixtures in concentrations equal or higher than 0.1% by mass for the purpose of textiles and leather processing, except processing with no release into waste water or in systems with special treatment where the process water is pre-treated to remove the organic fraction
Has this seen a reduction in the use of NPEs in the textile industry in the EU? Well, studies estimate that in 1999, the usage of NPEs in textile production in the EU was an estimated 8,000 tons/year. The German Association TEGEWA estimates that the consumption has reduced to about 5,000 tons/year. A majority of this consumption is in polymeric dispersions for coating technical textiles (e.g. tents), since the NPE acts as a glue to bind the coating. However, these technical textiles are not intended to be washed in a washing machine, thereby reducing the risk of NPEs washed out into rivers. Some studies on APEO production and consumption in the EU show that there are now less than 4 producers of Nonylphenol (NP) in the EU with an overall production level of 10- 50,000 tons/annum (exact figures are confidential), while Nonylphenol Ethoxylates (NPE) production in the EU is estimated at 32,000 tons/year in 2010 (CEPAD Report). This was estimated to 118,000 tons in 1997.
Though these are positive signs, we have to also consider the fact that traditional textile manufacturing has decreased substantially in the EU and shifted to countries such as China, Bangladesh, India, Vietnam, Brazil, Turkey and Mexico, where NPEs in textile processing are not regulated and extensively used due to cost- effectiveness and performance. These residues will remain on the final article, although NPEs with a chain length of more than 6 are easily soluble and get washed out in the effluent. These NPE residues on fabrics and garments imported into the EU will leach out into landfills or through simple home laundering. Although many studies in the EU have shown varying levels of detection of NPEs in imported articles, an average of 125 ppm (Eurofins data) can be derived from these test reports. This is not at all indicative of the actual use of NPEs in production. OECD(2004)emission scenario document estimates that, in general, 20 kgs of surfactants are used to treat 1 tonne of textile material. Using these figures for back-of-thumb calculations, it can be estimated that around 0.6% of NPEs used in production of an article can remain on the article. So, the solution to eliminate APEOs by 2020 rests greatly on the abatement of APEO usage in the textile producing countries.
An important step taken for such an abatement is the recent amendment in REACH Annexure XVII, Entry 46. As per this amendment "NPEs shall not be placed on the market in textile articles which can reasonably be expected to be washed in water during their normal lifecycle, in concentrations greater than or equal to 0.01% (100 ppm) by weight of that textile article or of each part of the textile article." This amendment will come into effect from 2020. This translates into a virtual USAGE BAN on NPEs in those countries where textile articles are being produced and exported to the EU.
But what can be done in the textile producing countries to eliminate NPEs from their production and discharge? Two things:
1. Replacement of NPE- based chemical formulations with substitutes
2. Implementation of end-of-pipe treatments in the form of Wastewater Treatment Plants (WWTPs)
Replacements of NPEs:
A number of alternatives to APEOs exist, of which the following 2 are most popular:
1. Alcohol Ethoxylates (AE): AEs (particularly, C12-C15 with ethoxylation between 3-7 EO units) are the most likely alternatives to replace NPEs as surfactants in textile processing. There has been a rapid growth in the use of AEs in laundry products and in surfactants worldwide, particularly in the US, India and Japan. AEs have low foaming characteristics, resistance to water hardness, good cleaning action and rapidly biodegrade. The possible prohibitive factor could be increase in formulation costs. In general, cost of NPEs is $ 1.7, while AEs could cost between $ 1.9- $ 2.1 per kg. Also, the availability of detergent -grade alcohols (alcohols with C12 or more atoms with a high degree of linearity), which are the raw materials for AEs, could be a constraint to the increased use of AEs to replace NPEs in textile formulations.
2.Glucose-based surfactants: These are based on alkylpolyglucosides, glucamides, glucamine oxides and alkylglucosamides. These surfactants are readily biodegradable & have much less toxicity than NPEs.
End-of-pipe measures: Environmental releases due to washing-off of NPEs from garments/fabrics can also be abated by effective Wastewater treatment measures. A normal Wastewater Treatment Plant (WWTP) in a textile processing unit consists of mechanical, chemical and biological treatments, often called Primary and Secondary treatments. In some cases, Tertiary treatment methods, such as ultrafiltration, RO membranes, electrochemical oxidation, activated carbon or ozonation are installed.
The EU Risk Assessment Report of 2002 suggests a worst- case scenario for NPEs entering an anaerobic WWTP: 19.5% is removed as Nonylphenol (NP) in the sludge, 45% is removed as degradation products comprising Nonylphenol (NP), nonylphenol-monoethoxylate (NPME), nonylphenoldiethoxylate (NPDE) and nonylphenoxy carboxylic acids (NPEC), while 35.5% is released as NPE in the effluent.
Advanced tertiary treatment measures can greatly eliminate the discharge of NPEs in the effluent. Some of these include:
1. Membrane filtration: Installation of Nanofiltration and Reverse Osmosis (RO) can effectively remove NPEs in the range of 70- 98% (Feenstra et al 2009), depending on the organic load. Disadvantages of Membrane filtration technology is high investment and maintenance costs and production of brine as waste. The advantage is that the permeate can be recycled and reused.
2. Oxidation treatment: Oxidation techniques can be used to 'crack' organic compounds with the use of strong oxidants like Ozone and Hydrogen Peroxide. A combination of Ozone +UV treatment called 'Advanced Oxidation Process (AOP)' can also be applied to accelerate the oxidation process. Studies indicate that AOPs can remove > 95% of NP from the effluent. One advantage of this technique is that no waste streams are produced.
3. Activated carbon filter: Here, the effluent is led over a fixed bed of granular activated carbon, where all non-polar organic contaminants are removed from the wastewater. A pre-treatment column to remove suspended solids is necessary to prevent clogging of the granular activated carbon filter. Removal efficiencies for NP of 90-99% have been reported. Granular activated carbon is the Best Available Technique (BAT) for removal of NP and other Endocrine Disrupting Chemicals from drinking water.
4. Electrochemical oxidation: In this technique, dimensionally stable anodes (DSA), which are typically prepared by thermal deposition of a thin layer of metal oxide (e.g., SnO, PbO2 or IrO2) on a base metal, are used for the mineralization of organic pollutants by taking advantage of the reactivity of hydroxyl radicals, which are generated by the electrochemical oxidation of water on the electrode surface. Electrochemical treatment leads to a rapid breakdown of the aromatic ring of NP.
The advantages of these end-of-pipe treatments for NPEs is that they also help to remove other pollutants present in the effluent, other than only NP/NPEs.
Alkylphenol Ethoxylates (APEOs) are one of the main priority chemical groups targeted for elimination across all pathways- that is products, wastewater and sludge- in the supply chains of ZDHC Signatory Brands. This commitment has to be met before 2020. The REACH Annexure XVI amendment that restricts NPEs to 100 ppm in textile articles intended to be washed, will also come into effect in 2020.
It is seen from reports that the production and consumption of NP and NPEs in the EU has reduced drastically, but the same cannot be said about the countries where processing of textiles is happening. The challenge of eliminating APEOs is two -fold: (i) how to prevent usage in textile production so as to eliminate residues in articles imported into the EU and (ii) how to prevent the discharge of NP/NPEs from production facilities or Municipal wastewater treatment plants into river bodies.
For this, NPE- based textile chemical formulations should be replaced with alternatives such as alcohol ethoxylates, even though it may increase costs to the producer. Also, wastewater treatment techniques should be implemented and monitored to ensure that NPEs are broken down into harmless molecules before discharge of the effluent to the environment. In most of the benchmark studies published by Brands committed to Detox, APEOs have been detected in the wastewater streams of almost all supplier facilities in almost all producing countries.
Thus, an important aspect in this challenge is to create awareness about APEOs and train all stakeholders in the textile and footwear supply chain-including chemical manufacturers-about APEOs and methods to eliminate the same from production processes.
(Prasad Pant is CEO, NimkarTek Technical Services Pvt Ltd)