Use of Wetland for Dye-house Waste Waters Purifying Purposes

Abstract

Textile finishing processes produce waste waters burdened by high amounts of dyestuff, which has not been chemically bonded to the fiber in the process of fixation. Also, a great threat to the inlet water ways and the environment itself are high quantities of salt (e.g. NaCl or Na $_2$ SO $_4$ ), used in the processes of cotton dyeing. Although, recently more and more new physical and chemical purifying methods are being developed, with the emphasis on membrane processes, this paper revises an alternative solution to the problem, which is adapting and constructing a purifying system similar to the processes which have been occurring in the nature forever.

Efficiency of such constructed wetland will depend on selection and mass relation of natural adsorbents, which should correlate to the natural geological profiles. In this paper wetland was optimized within laboratory investigations and then used as an only method employed in order to purify dye-house wastewater. Optimized combination of purifying media along with Phragmites Australis achieved reduction of measured biological parameters (COD, BOD $_5$ , TOC, AOX, el. conductivity, pH, NH $_4^+$ , NO $_3^-$ , NO $_2^-$ , total P and the amount of Cl $^-$ ions). In order to significantly reduce SAC values, another purifying method (e.g. chemical) should be employed.