Evaluation of corrosion and scaling tendency of polyester textile dyeing effluent, Haridwar, Uttarakhand, India.

Textile dyeing industries are regarded as one of the most polluting by virtue of the chemicals used and wastewater released. A great deal of chemicals, fasteners, dispersing agents is employed in the stages of dyeing and finishing. The aim of the study was to evaluate scaling and corrosion tendency of polyester textile dyeing effluent using Langelier saturation index (LSI), Ryznar stability index (RSI), and aggressiveness index (AI). The estimation of water stability indices helps in assessing the scaling and corrosive nature of wastewater which in turn facilitates evaluating the condition of the pipelines and valves. Wastewater released from textile dyeing units contains high levels of color (892 ± 20Pt-Co), chemical oxygen demand (2461 ± 48.45 mg/L), electrical conductivity (2906 ± 5.77 μS/cm), and sulfate (6620 ± 7.22 mg/L). The LSI ranged from 2.12 to 3.45, RSI varied from 2.84 to 5.62, and AI varied from 13.67 to 14.99. It was found from the results that the polyester textile dyeing effluent was scaling and non-aggressive. Also, the pipes containing this effluent have to undergo regular maintenance so that they are not blocked by scales which can render financial losses to the industry.