experimental design for removal of fe(ii) and zn(ii) ions by different lactic acid bacteria biomasses

this paper investigates the removal of iron and zinc from aqueous solution with dairy wastewaterin three different biomasses such as lactobacillus delbrueckii ssp bulgaricus (lb-12), streptococcus thermophillus(stm-7) and a combination of both this bacteria culture (yc-380) and the optimization of removal efficiencyusing minitab program. a full 23 factorial design of experiments was applied to determine the optimumconditions of removal of fe(ii) and zn(ii) from aqueous solution. the three tested factors were biomassconcentration (5-15 g/l), ph (3-9), and temperature (20-40 °c). the optimum biomass concentration, ph andtemperature were found to be 15 g/l, 9 and 20 °c, respectively. under optimal value of process parameters, 90-100% fe(ii) and 70-90% zn(ii) removal were obtained with all tested biomasses. removal results indicated thata combination of both this bacteria might be a promising biomass alternative to st-m7 and lb.12 in removingzn(ii) and fe(ii) ions from waters.