Abstract

Treatment of effluents from batik producing enterprises to removal dyes and other impurities is inevitable as these enterprises are becoming ubiquitous in many cities in Tanzania. Wastewater from batik production processes are discharged haphazardly without treatment. In this study, preliminary results on adsorption potential of defatted Moringa oleifera crude seed extract (DMOCSE) and fuel wood ash (FWA) for dye and chemical oxygen demand (COD) in batik processing wastewater (BPW) are presented. Batch and column adsorption studies were conducted using varied dye concentrations, adsorbents dosage, contact time and pH. 7% (w/v) DMOCSE at the dosage of 15 to 25 ml/L produced minimum residual dye in BPW with initial color ranging from 480 to 675 mgpt-Co/L. Optimum contact time for DMOCSE ranged from 1.5 to 2.5 h and pH 7.5 to 9.5 with 75.5 to 93% dye removal efficiency. FWA at optimum dosage of 25 g/l, contact time of 1.5 to 3 h and pH 8.5 to 11.5 removed 78.8 to 84% of dye. FWA and DMOCSE reduced 98 and 64% of COD. The FWA packed column with depth of 20 and 25 cm achieved 99% dye removal after 4 to 6 h of retention time. The findings reveal that DMOCSE and FWA have potential to treat BPW in both batch and column mode.

Key words: Dye-rich wastewater, impurities removal, natural adsorbent.