Options and Solutions for Textile Effluent Decolorization Using Some Specific Physico-Chemical Treatment Steps

Abstract

The environmental issues associated with residual colour in treated textile effluents are always a concern for each textile operator that directly discharges, both sewage treatment works and commercial textile operations, in terms of respecting the colour requirements. This paper aims to help a textile operator to decide on options available to plan forward strategy that will ensure compliance with the environmental regulators' requirements on a progressive basis. To achieve this objective the paper is structured in order to present various options and solutions that are explained and developed mainly based on different physico-chemical treatment steps (i.e. adsorption using different unconventional adsorptive materials as 'low cost' adsorbents of coal ashes, sawdust wastes, peat and comparisons with a classic commercial 'activated carbon'; catalysed chemical oxidation with hydrogen peroxide; coagulation-flocculation with iron salts and organic polyelectrolyte) integrated into a specific order in the wastewater technological treatment process for decolorization or large-scale colour removal processes of textile effluents produced into a private Northern Romanian textile plant. The influence of different operating parameters (i.e. pH, material or chemical reagent concentration, temperature, operational time, agitation and operational working regime) is discussed together with the textile effluent treatment efficiency obtained for each studied influencing parameters (the best solutions for each parameters are in view and discussed). These technical and operational treatment solutions are both threats and opportunities for the textile operator, and the best colour removal option is obtained from combination of technologies or proposed treatment steps rather than from one single-stage process.

Textile Organic Dyes – Characteristics, Polluting Effects and Separation/Elimination Procedures from Industrial Effluents – A Critical Overview

“…The environmental issues associated with residual dye content or residual colour in treated textile effluents are always a concern for each textile operator that directly discharges, both sewage treatment works and commercial textile operations, in terms of respecting the colour and residual dye requirements placed on treated effluent discharge (Zaharia et al, 2011). Dye concentrations in watercourses higher of 1 mg/L caused by the direct discharges of textile effluents, treated or not, can give rise to public compliant.…”

“…Additionally, physico-chemical processes (i.e. adsorption, chemical precipitation, coagulation-flocculation, and ionic exchange) can be used to separate dissolved, emulsified and solid-separating compounds from water environment (Anjaneyulu et al, 2005;Babu et al, 2007;Robinson et al, 2001;Suteu et al, 2009a;Suteu et al, 2011a;Zaharia, 2006;Zaharia et al, 2009;Zaharia et al, 2011). The partial and complete mineralization or decomposition of pollutants can be achieved by biological and chemical processes (biological processes in connection with the activated sludge processes and membrane bioreactors, advanced oxidation with ozone, H 2 O 2 , UV) (Dos Santos et al, 2004 ;Oztekin et al, 2010 ;Wiesmann et al, 2007 ;Zaharia et al, 2009).…”

“…specific mechano-physical, chemical, electrochemical processes, etc.) and also biological processes (Suteu et al, 2009;Zaharia, 2006;Zaharia et al, 2011). Table 6.…”

Comparative overview of primary sedimentation-based mechanical stage in some Romanian wastewater treatment systems

“…of basic aromatic products for alimentary industry, food, flavours as C14-C16 aldehydes, γ and ω lactones, cyclic cetones, esters, glycolates, ntermediate fractions from petroleum products) [20,22], [23] (with WWTP No. 2) aeration/oxidation basin, 2 secondary radial settlers of 35 m in diameter, chemicals used as nutrients (10% industrial lime for pH correction, 10% tri-sodium phosphate, 10% urea); it exists also 1 biofilter (h=4 m, chemically inert granite support, 4-8 cm-material size); for sludge line -(3) sludge evacuation (pumping, recycling) and in-excess sludge treatment (mechanical and gravitational concentration to 6-10% solids, and dewatering); A required standard quality must be related to the treated wastewater when it is used as processing water, or for recycling/reusing goal, and also if is discharged in local receiving watercourse [1,5]. The specific site standards, or permitted maximal limits are considering: (i) requirements of permit conditions (compliance with permit requirements), i.e.…”

“…As society structure becomes more complex, water quality requirements, produced wastes, management systems and tools, and environmental impact due to wastes (gaseous, liquid-asWW, solid) become greater in complexity, subtlety, and magnitude [1], [2]. Modern society is centred closed to an industrial city, where wastewaters (WWs) flow is generally large and discharged in a complex sewer system, and/or emisar after its corresponding required treatment.…”