Biogenic nitric oxide from wastewater land application

The importance of municipal wastewater land application to nitric oxide production and transport in soil was studied through the formulation and conduct of a comprehensive laboratory testing protocol. Nitric oxide (NO) is a precursor in the formation of tropospheric ozone which can directly impact public health and the environment. It is the uncertainty in the NO budget, and its relation to O3, that motivates the need for measurements and modeling of NO flux from soils. Wastewater-amended soil is potentially one important component of that budget. NO emissions reported here were measured from: a well-characterized unamended soil, water-amended soil, and wastewater-amended soil in the laboratory in a dynamic test chamber. Laboratory results indicate that NO emissions from the selected sandy loam soil ranged from 0.3 to 0.4 ng N m-2 s-1 per cm2 of unamended soil, while water-amended soil emissions ranged from 0.4 to 0.7 ng N m-2 s-1 per cm2. NO flux from wastewater-amended soil ranged from 1.0 to 1.2 ng N m-2 s-1 per cm2 of applied soil.