Evaluation of Integrated Anaerobic/Aerobic Conditions for Treating Dye-Rich Synthetic and Real Textile Wastewater Using a Soda Lake Derived Alkaliphilic Microbial Consortia

Abstract

Textile industry wastewater (WW) has intense color, high chemical oxygen demand (COD), pH, and salinity, making it challenging for conventional treatment. Soda lakes, with high alkalinity and salinity, host diverse microbes capable of textile dye degradation. This study evaluated anaerobic/aerobic reactors using alkaliphilic microbial consortia from Lake Chitu, an Ethiopian soda lake, for treating synthetic and real textile WW. The experimental setup consisted of a first-stage anaerobic reactor followed by a second-stage aerobic reactor, operating continuously with a predetermined flow rate and hydraulic residence time. After evaluating synthetic WW, real textile WW was collected in two batches (rounds I and II). The treatment setup removed 99% of the dye color for synthetic WW, 98% for round I, and 96% for round II. COD removal was 87% for synthetic WW, 86% for round I, and 93.37% for round II. TKN removal reached 90% for synthetic WW, 91% for round I, and 96% for round II at a steady state. Residual COD and TKN values met the final effluent discharge standards. GC–MS and IR analyses revealed that dyes were broken down into intermediate organic compounds under anaerobic conditions and further degraded into smaller molecules under aerobic conditions. This integrated reactor approach effectively removes dyes and enhances COD and TKN removal. The study’s novelty lies in evaluating both synthetic and real textile WW using integrated reactors under alkaline conditions in a continuous process, inoculating alkaliphilic consortia, without pre-enrichment or external nutrient addition to real WW. The study provides insights into the effectiveness of alkaliphilic microbial consortia derived from soda lakes for treating textile WW using integrated reactor conditions. Reactor microbiome characterization is needed to further explore microbial diversity and community structure.