Bioremediation of Nitrate-Contaminated Wastewater and Soil

Water utilization is in a steep hike due to urbanization and population increase. On the other hand, pollution of fresh water due to human activities is increasingly a major concern as it affects economy and growth of a nation. Among various water pollutants, nitrogen compounds form a significant role in wastewater contamination due to increase in anthropogenic sources like agriculture. Release of nitrate into fresh water poses severe problems including eutrophication, methemoglobinemia, and other health issues. Thus, nitrate contamination in water and soil has become a growing environmental concern. According to USEPA standards, the maximum contamination level for nitrate is 45 mg L−1, and the same standard is adopted by the Bureau of Indian Standards (BIS). Among various technologies employed for treating nitrate-contaminated water, biological denitrification is one of the more versatile and promising methods widely being employed. The treatment of NO3− using bacteria referred as denitrification or bioremediation of nitrate has high separation efficiency. This chapter focuses on various biodenitrification processes, immobilization of microorganism, and different reactors employed for removing the nitrate from water. Different reactor designs ranging from fixed-bed reactors to biological aerated filters have been demonstrated for effective denitrification.