Selection of Optimized Coagulator for Pre-treatment of Mazandran Textile Wastewater Using Jar Test and Analytic Hierarchy Process (AHP)

Textile industry is of those industries whose wastewater includes different pollutants. Therefore, conventional treatments are not able to treat all of the textile wastewater pollutants. Chemical coagulation may be suitable for the removal of Total Suspended Solids (TSS) as a pre- treatment.
Material and

In this study, after monitoring the wastewater from Mazandaran textile factory, which is currently discharged into the river without treatment, Jar test, alum, calcium oxide, ferrous sulfate, ferrous chloride and barium chloride were applied to investigate the maximum amount of TSS removal with the change of pH.

In addition to the type of coagulator, other parameters such as coagulation cost, sensitivity to pH change, the amount of sludge generation and side effects are effective on selection of coagulation. Hence, to select optimally, AHP was applied using Expert choice software considering the important effective parameters in decision making. Moreover, the score of each parameter was used considering the related experts’ opinion included in the questionnaires.

The results of Jar test and AHP indicated that calcium oxide was the best choice for reduction TSS in thye wastewater from Mazandaran textile factory. Also the Jar test results indicated 70% dye removal and 30% COD removal using calcium oxide as a coagulant.