Chapter 6 - Biological Solutions

Abstract

Biological solutions to problems in environmental engineering often involve engineers integrating apparently disjointed biological knowledge, and tailoring this knowledge to address specific engineering challenges. This chapter describes how the emerging discipline of environmental biotechnology contributes to the field of environmental engineering. Biological solutions help in assessing the risk to human health and determining the effectiveness of environmental engineering design decisions to reduce this risk to an acceptable level for the least possible cost. Molecular biology-based forensic tools are increasingly used by researchers in environmental engineering to address the problem of identifying the source of microbiological pollution for Section 303d waters. This emerging field of microbial or bacterial source tracking (MST or BST) often relies upon molecular biology-based assays to identify specific microorganisms and to link environmental microbiological pollution to its source. Wastewater treatment plants are also a biological solution to the problem of highly concentrated organic pollution. In such wastewater treatment plants, the processes of microbial degradation of organic waste with biomass production followed by sedimentation are encouraged to occur in a highly controlled environment. In the past 10 years, environmental engineers have collaborated with microbiologists to develop alternative technologies for total nitrogen removal that avoid some of the inefficiency of nitrification followed by denitrification. The alternative biological solution to total nitrogen removal is known as anaerobic ammonia oxidization (ANAMMOX). In the ANAMMOX process, specific populations of microorganisms couple the reduction of nitrite to the simultaneous oxidization of ammonia to produce dinitrogen gas.