Short-Term Effects of Wastewater Land Application on Soil Chemical Properties

Land application of wastewater has been accepted as an effective wastewater treatment method and disposal option in semiarid and arid areas in the world. Although it has economical, environmental, and social benefits, it is sometimes questioned as an environmentally sound method. Water mass balance method has proved to be an effective approach to designing a wastewater land application system to remove nitrogen at the municipal wastewater treatment plant at the City of Littlefield, Texas, USA. The study in this paper was to evaluate the short-term effects of wastewater land application on soil chemical properties at the same site from 16 June 2006 to 28 June 2007 with the system designed by the water mass balance method. Soil samples were taken at the start and at the end of this study at different depths from soil surface down to 91 cm at the research site (54x18 m), and analyzed for pH, total Kjeldahl nitrogen, nitrate-nitrogen, ammonia-nitrogen, electrical conductivity, calcium, magnesium, sodium, and sodium adsorption ratio. The results showed that there was no negative change of those soil chemical properties during the research period in this wastewater land application system designed by water mass balance method.