Removal of heavy metals in metal industrial wastewater by using algae

Abstract

With the accelerated progress of industrialization in the world, a large number of environmental issues have arisen one after another, among which the pollution of water resources is essential to solve. There are a lot of heavy metals in industrial wastewater produced by human activities, which are difficult to be degraded without treatment and they can carry a lot of toxicity to harm water sources and land. Therefore, it is of great importance to research the technology of removing heavy metals from industrial wastewater. After technological advances in the removal of heavy metals by several conventional methods, the use of natural plants for removal is receiving increasing attention. As plants commonly found in nature, algae have become a hot spot for environmental improvement and resource recovery in recent years. Microalgae, due to their own structural characteristics, can be transformed to reduce the harmful effects of metals through extracellular defence mechanisms, intracellular bioaccumulation, biotransformation and metal rejection, biotransformation or metal detoxification and metal rejection. The application of algae plants in industrial production and recycling processes is not only easy to operate, economical and it does not produce secondary toxic substances. This thesis introduces several existing mature technologies and explain the principle of microorganism about removing heavy metals from wastewater. The mechanism of removing heavy metals by micro-algae is described in detail and lots of related experiments are cited to prove the availability, explore their efficiency. The effectiveness of microalgae in removing heavy metals from metal industries is strongly proved. Then current situation and future prospects are discussed. Finally, the summary about the whole thesis is made.