Immobilized Microalgae using Alginate for Wastewater Treatment

Abstract

Organic and inorganic substances are released into the environment because of domestic, agricultural, and industrial activities which contribute to the pollution of water bodies. Removal of these substances from wastewater using conventional treatment involves high energy cost for mechanical aeration to provide oxygen for aerobic digestion system. During this process, the aerobic bacteria rapidly consume the organic matter and convert it into single cell proteins, water, and carbon dioxide. Alternatively, this biological treatment step can be accomplished by growing microalgae in the wastewater. Chlorella vulgaris immobilized in calcium alginate was used to study the removal efficiency of main nutrients in wastewater such as ammonium and phosphate that act as an important factor in microalgae growth. The immobilized cells demonstrated higher percentage of ammonium and phosphate removal of 83% and 79% respectively, compared to free-suspended cells (76% and 56%). COD removal recorded was 89% and 83% for immobilized cells and free-suspended cells, respectively. The kinetics parameters of nutrients removal for immobilized C. vulgaris in synthetic wastewater were also determined. The specific ammonium removal rates (RA) and phosphate removal rates (RP) for Chlorella vulgaris in synthetic wastewater were 8.3 mg.L-1day-1 and 7.9 mg.L-1day-1, respectively. On the other hand, the kinetic coefficient for each nutrient removal determined were kA = 0.0462 L.mg-1 day-1 NH4 and kP = 0.0352 L.mg-1 day-1 PO43-. This study proves the application of immobilized microalgae cells is advantageous to the wastewater treatment efficiency. Furthermore, optimization on the immobilization process can be conducted to further improve the nutrients removal rates which potentially can be applied in the large-scale wastewater treatment process.

Building Information Modeling (BIM) application towards environmental sustainability

“…BIM is categorized as a revolutionary technology, transforming the entire process of designing, planning, constructing, and managing buildings. Previous studies have identified barriers to BIM implementation, including a lack of awareness [6], insufficient knowledge about BIM [7] and resistance to change [8]. These findings suggest that improving awareness and knowledge about BIM can improve the industry's perception of BIM implementation.…”

Alginate: Wastewater Treatment

“…Microalgae have shown great potential to treat industrial wastes such as petroleum, heavy metals, dyes, and toxic gases [16].…”

“…Halim and Haron [16] used C. vulgaris immobilized in calcium alginate to study the removal efficiency of main nutrients in wastewater such as ammonium and phosphate. [23].…”

“…Even though the contribution of alginate in removing nutrients is evident, the primary mechanism of nutrient removal through microalgae uptake is more significant compared to the chemical and physical processes. Moreover, the utilization of immobilized cells using alginate matrix provides a protective environment against mechanical shear stress and external microorganisms contamination which enhanced the overall nutrients removal performance [16].…”