The ever-increasing number of pollutants released into the environment drives the search for new treatment technologies or the modification of existing ones. In this sense, innovation in biofiltration systems seems promising, and therefore, a book on the current developments and innovations on its subject is very appropriate. Biofiltration is a relatively emerging new technology applied to the treatment of wastewater and other toxic substances. Over the past two decades, this technology has become an economically viable process for treating the wide variety of unruly pollutants released into the environment. For example, it is speculated that the US biofiltration market will reach more than $100 million by 2020. This book aims to show how innovation in biofiltration can provide effective solutions to overcome the serious problem of water pollution worldwide. The removal of contaminants will result from the combined effects of biological oxidation, adsorption, and filtration processes. Many physicochemical and operational factors influence the performance, treatment costs, and long-term stability of biofilters for wastewater treatment. This book focuses on identifying factors that affect biofiltration, explains their influence, and provides guidelines on how to control these factors to optimize better control over the control of pollutants present in wastewater treatment plants. The fundamental basis of treatment in biofilters is the action of microorganisms that degrade pollutants, and consequently, the book also discusses in depth the microbial ecology of biofiltration.