Green technology in treating aquaculture wastewater

Aquaculture contributes a large number of world food supplies which increases rapidly over these few years. Similarly, there is a huge development of aquaculture in Malaysia over the years. However, aquaculture activities generate wastewater with high in nutrients where developing a proper treatment system is crucial. An appropriate wastewater treatment is needed to reduce uncontrolled pollution and environmental impacts while sustaining the development of aquaculture industry. Hence, this study focuses on the implementation of green technology method namely physical and biological in treating aquaculture wastewater. Major effect of releasing wastewater that is rich in nutrients is mainly eutrophication. This problem could be mitigated utilizing microalgae whereby the nutrients used as feed for microalgae growth. However, excess nutrients will cause undesirable consequences such as algal blooms due to the rapid growth of microalgae. Therefore, harvesting microalgae after treating the wastewater helps in the prevention of this problem. Current microalgae harvesting technology depends on sophisticated and complex approaches such as hollow fiber filtration, chemical flocculants and centrifugation, which are deemed feasible if high value products were obtained. The potentiality of Moringa oleifera, filamentous fungus (Aspergillus niger), microalgae (Ankistrodesmus sp.), Biofloc Technology (BFT) and chitosan as bio-flocculant were investigated in harvesting microalgae, Chlorella sp.. This type of development in phytoremediation and phycoremediation with continuous bio-harvesting could promote the use of sustainable green technology for effective aquaculture wastewater treatment.