A feasibility study of piggery wastewater as a cost-effective media using sodium alginate immobilized microalgae

In recent years, microalgal biotechnology has experienced significant growth across multiple industry sectors due to the versatility of various microalgae species. Manny applications for both microalgae themselves and microalgae products derived from algal biomass are mentioned in this thesis. However, the economic inefficiency and difficulties in commercial scale-up production arise from the high costs of chemical nutrient media used for algal cultivation. Piggery wastewater offers an alternative to commonly used chemicals, like Bolds basal media, and contain much of the nutrients needed for algal growth. This thesis explores the possibility of using PWW as a nutrient media when cultivating Chlorella sp. microalgae immobilized in sodium alginate. Different concentrations diluted with distilled water were tested in order to find the optimal concentration yielding the most growth. Growth patterns were measured by optical density and nutrient depletion were measured by analyzing the total nitrogen and total phosphorous in the samples. A 70% depletion of total nitrogen was observed from all variants of immobilized microalgae beads, while a 90% depletion of total phosphorus was observed from all variants of immobilized microalgae. The thesis also explores microalgae immobilization optimization using sodium alginate. Different sized beads were tested to find the bead yielding the best growth conditions for the immobilized algae inside. The results from these experiments offer information useful for future applications of microalgae cultivation and sodium alginate immobilization.