Defining the kinetics of the novel application of anaerobic acetogenics for treating textile dyeing wastewater

A bench-scale completely mixed reactor was operated under anaerobic acetogenic conditions to treat real life wastewater from a textile processing and dyeing facilities. The reactor performance data was modeled with respect to removal of soluble chemical oxygen demand (SCOD) and color to critical elements that needs to be neutralized before discharge to the environment. The reactor performance is defined by a first order model for both SCOD and color transformation. Transformation of SCOD increase with length of reactor operation indicating that culture acclimation plays a significant role in the performance of the reactor (day 2: k = 0.16 day− 1, day 7 k = 2.17 day− 1; an increase of roughly 13 folds). Upon optimum operation first order rate constant “k” for the degradation of the textile dyeing wastewater was 0.047 h− 1 (95% confidence bound; 0.030, 0.064, r2 = 0.84, RMSE = 10.5). Culture acclimation facilitates extent of SCOD removal (day 2: 39.7%, day 7: 89.7%). Food to microorganism ratio affects both the kinetic parameter “k” and extent of SCOD transformation with an optimum F/M ratio of 0.1. The importance of culture acclimation was evident in color removal as well, between day 5 to day 9 of operation. The kinetic constant “k” increased by 10.2 folds (k = 0.094 day− 1 to k = 0.96 day− 1). The extent of color removal also increased by a factor of 2.9 (day 5: 27.4%, day 9: 79.2%) with acclimation. The experimental and modeling program validates that anaerobic acetogenic process can be successfully applied to treat textile processing dyeing wastewater.