Integration of physio-biological methods for remediation of dyes and toxic metals from textile wastewater

Abstract

Textile wastewater, a heterogeneous mixture of contaminants, major source of dyes and heavy metals in aquatic ecosystems. This study integrated physical adsorbents, biological species, and electro-kinesis as post-treatment for textile effluents. Pond experiments were conducted to determine the removal efficiency of dyes and toxic metals (Cadmium and Chromium) in a batch system. The setup consists of four treatment lines: AD-P (Adsorption Pond), DW-P (Duckweed Pond), MA-P (Algae Pond), and FG-P (Fungus Pond), each with three transparent plastic aquaria in line. Two runs were conducted: the first using a mixture with 250 mg/L of dyes and 15 mg/L each of cadmium and chromium, and the second with an additional 500 mg/L of dyes and 25 mg/L of cadmium and chromium. Samples were collected on every fourth day for 12 days. The highest dye decolorization (74.3 %) was observed with fungi, followed by duckweed (65 %), algae (57.5 %), and dolomite (39 %). Maximum chromium removal (78.3 %) occurred in the algal pond, and the highest cadmium removal was achieved by fungi (73.8 %). Electro-kinesis further enhanced the extraction of chromium and cadmium, with algae showing the highest extraction rates. The integrated system proved effective for removing dyes, chromium, and cadmium from textile wastewater and supported the broader application of physio-biological methods, recommending the use of biological species and electro-kinetic remediation.