This book covers various aspects of heavy metal contamination in wastewater and its removal by microbial-based approaches. The heavy metal contamination in water is generally caused due to natural and anthropogenic activities. There are many industrial processes responsible for such a contamination, for example, leather tanning, coal washeries, agriculture activities, chrome plating and paint industries. The industrial effluent directly or indirectly discharges into water sources, and heavy metal containing wastewater decreases the quality of surface water and groundwater. The heavy metal contamination causes various types of health issues in human and other living organisms, including kidney and liver damage, heart failure, mental retardation, cancers, and skin and gastric problems. The high level of heavy metal concentration in the cell generates reactive oxygen species (ROS) which may cause damage to cell organelles.

Due to their high toxicity, there is an urgent need to develop effective heavy metal removal method for wastewater treatment. There are several conventional methods available for the removal of heavy metal ions from contaminated sites. These methods have some disadvantages such as the generation of secondary toxic sludge and high operation cost. Hence, it is required to develop cost-effective and eco-friendly methods for decontamination. Microorganisms have tendency to accumulate heavy metal ions into their intracellular space and can grow in various high-stress environments, and microbial-based methods are considered as eco-friendly and cost-effective. Moreover, the integrated approach of wastewater treatment and utilization of microbial biomass for bioenergy production can be beneficial in terms of heavy metal bioremediation and zero waste generation. This book focuses on the heavy metal contamination, their toxicity and microbial methods for the removal of heavy metal ions from contaminated sites.