Nitrogen compound pollution associated with the use of sewage sludge compost and limestone outcrop residue under saline irrigation

Abstract

The use of composted sewage sludge and limestone outcrop residue in land rehabilitation, soil improvement, and technosol making can influence the mobility of nitrogen compounds in groundwater. This experiment analyzed this source of possible pollution under an experimental design based on the use of columns (0–30 cm) formed by both wastes and a heavy irrigation regime. Two waters of different quality (saline and non-saline) were used for irrigation. The presence of nitrate, nitrite, and ammonium in the leachates was checked. The environmental risk due to the presence of nitrogen species associated with the use of these materials was very low in general, although nitrate was the most important compound affected by the use of sewage sludge compost and saline water. The combination of saline water for irrigation with the compost has to be seriously considered as a source of pollution for surface and ground waters, and the use of both resources may be a key factor to be studied (low-quality water and sewage sludge compost).