In this study, batik effluent treatment was carried using immobilised Chlorella sp. in batch culture mode. This two-part study firstly determined the most suitable immobilised carrier matrix for Chlorella sp. immobilization process. In this study, three immobilised carrier namely, starch, carboxylmethylcellulose and alginate were evaluated. Higher decolourization of batik effluent of 77.9% was obtained from the treatment using alginate as a immobilised matrix. Further optimization on the effect of pH, light intensity and microalgae bead concentration on decolourization and total nitrogen (TN) removal by alginate-immobilised Chlorella sp. were determined using Box-Behnken Design (BBD) approach. The highest decolourization of batik effluent of 80% was achieved when the treatment was perfomed using 150 microalgal bead concentration, at pH 12, and 1000 lux. Whereas, the maximum TN removal of 71% with uptake rates of 4.9 mgL-1d-1 was observed for the cultivation at pH 7 with 150 microalgae bead concentration, and 1000 lux. The increase of pH value and microalgal bead concentration had a strong effect on decolourization and TN removal of batik eflluent. These results demonstrate that the alginate immobilised Chlorella sp. has a great potential to be used as an alternative approach to treat batik effluent before discharge.
Key words: Immobilised microalgae, decolourization, optimization, batik effluent, removal
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