Evaluation of Emission of Greenhouse Gases from Soils Amended with Sewage Sludge

Authors: PARAMASIVAM, S - SAVANNAH ST UNIVERSITY; FORTENBERRY, GAMOLA - FL AG & MECHANICAL UNIVER; JULIUS, AFOLABI - SAVANNAH ST UNIVERSITY; SAJWAN, KENNETH - SAVANNAH ST UNIVERSITY; Alva, Ashok

Submitted to: Journal of Environmental Science and Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2007
Publication Date: 2/1/2008
Citation: Paramasivam, S., Fortenberry, G.Z., Julius, A., Sajwan, K.S., Alva, A.K. 2008. Evaluation of Emission of Greenhouse Gases from Soils Amended with Sewage Sludge. Journal of Environmental Science and Health. Vol 43:178-185.

Interpretive Summary: Emission of trace gases, including those which are originated by the agricultural activities, has been linked to climate change. In this study emissions of methane (CH4), nitrous oxide (N2O) and CO2 were investigated from two soils (a sandy soil from Florida and a loamy sand from Georgia) which received different rates (0, 24.7, 49.4, 98.8, and 148.3 metric tons per hectare) of either domestic or industrial origin sewage sludge. Increasing rates of sewage sludge amendment increased the rate of trace gas emissions. Cumulative emission of trace gases over a period of 25 days decreased in the order: CO2 > N2O > CH4. The emission of trace gases was greater when the soils were amended with sewage sludge that was of domestic origin as compared to that of industrial origin. The emission of trace gases was positively correlated with an increase in microbial activity. This study demonstrated a potential for increased emission of trace gases when the soils are amended with high rates of organic amendments.

Technical Abstract: Increase in concentrations of various greenhouse gases originated by various human activities, including agricultural origin, could contribute to climate change. Anthropogenic activities such as cultivation of flooded rice and application of waste materials, such as sewage sludge which are rich in C and N, as soil amendments could contribute to the increase in emission of greenhouse gases such as methane (CH4) and nitrous oxide (N2O) into the atmosphere. Therefore, evaluation of flux of various greenhouse gases from soils amended with sewage sludge is essential to quantify their release into atmosphere. Two soils with contrasting properties (Candler fine sand [CFS] from Florida, and Ogeechee loamy sand [OLS] from Savannah, GA) were amended with varying rates (0, 24.7, 49.4, 98.8, and 148.3 Mg ha-1) of two types of sewage sludge (industrial [ISS] and domestic [DSS] origin. The amended soil samples were incubated in anaerobic condition at field capacity soil water content in static chamber (Qopak bottles). Gas samples were extracted immediately after amending soils and subsequently on a daily basis to evaluate the emission of CH4, CO2 and N2O. The results showed that emission rates and cumulative emission of all three gases increased with increasing rates of amendments. Cumulative emission of gases during 25-d incubation of soils amended with different types of sewage sludge decreased in the order: CO2 > N2O > CH4. The emission of gases was greater from the soils amended with DSS as compared to that with ISS. This may indicate the presence of either low C and N content or possible harmful chemicals in the ISS. The emission of gases was greater from the CFS as compared to that from the OLS. Furthermore, the results clearly depicted the inhibitory effect of acetylene in both soils by producing more N2O and CH4 emission compared to the soils that did not receive acetylene at the rate of 1mL g-1 soil. Enumeration of microbial population by fluorescein diacetate (FDA) and most probable number (MPN) procedure at the end of 25-d incubation demonstrated a clear relationship between microbial activity and the emission of gases. The results of this study emphasize the need to consider the emission of greenhouse gases from soils amended with organic soil amendments such as sewage sludge, especially at high rates.