Effect of supplement and dilution on microalgae biomass growth in pome from effluent of biogas plant of Felda Sg Tengi palm oil mill

The purpose of this research is to investigate the effect of supplement and dilution of POME from biogas plant of Felda Sg Tengi Palm Oil Mill on the growth of microalgae species, Chlorella sorokiniana. The research is done by studying the main effect and interactive effect of four variables controlling the process on the maximum biomass concentration and maximum specific growth rate of microalgae in a batch fermentation. Linear regression was then used to determine the relationship between the variables and the objective function of maximum biomass concentration, and the objective function maximum specific growth rate. Four variables were introduced for 2⁴ factorial experiment, namely carbon dioxide (CO₂) concentration, gas mixture sparging rate, supplement concentration and dilution level. The data obtained from the experiment were fitted into logistic equation by using MATLAB R2013a software to get the value of both maximum specific growth rate and maximum biomass concentration. Then the main effect of each variable and the Interactive Effects between variables on the objective function maximum biomass concentration and maximum specific growth rate were evaluated by using Yate‟s Method. The results showed that the main effect of each variable is positive on both maximum biomass concentration and maximum specific growth rate. By increasing each of the variables from low level to high level will increase the biomass concentration. From regression evaluation, it showed that CO₂ concentration has a very critical effect on biomass growth and on maximum specific growth rate, followed by gas mixture sparging rate, supplement concentration and dilution level. In conclusion, the study of CO₂ sequestration by microalgae and the effect of supplement and dilution in POME on both maximum biomass concentration and maximum specific growth rate can be determined by this method.