Reuse of treated wastewater for turf irrigation is often viewed as one way to maximize existing urban water resources. The aim of this study is to evaluate the applicability of treated wastewater for turfgrass and assess the effects of continuous use of treated water on the soil and crop. Two turfgrass plots irrigated with drinking water and treated wastewater were monitored over a two-year period. Physical and chemical parameters in the soil and foliar tissue were analyzed. Plants irrigated with treated wastewater had highest sodium content. There were no negative effects with respect to changes in soil pH but a significant increase in electrical conductivity and sodium content was observed in wastewater-irrigated soil. Treated wastewater could be used as a resource for agricultural irrigation since it contributes phosphorus and organic matter. However, it is necessary to consider that several crops could be negatively affected by wastewater irrigation because of the sodium content and this should be taken into account when water-sprinklers are in use, since this is the case in the present study. The benefits of irrigation with treated urban wastewater include contributing plant nutrients to turfgrass while conserving freshwater.

A romaine-type lettuce (Lactuca sativa L.) was cultivated over three crop seasons (spring 2005, spring 2006 and autumn-winter 2006) in six 36 m(2) plots in Alcázar de San Juan, Spain. A drip irrigation system was used to water all plots: five plots with drinking water and one plot with wastewater from the activated sludge system of a wastewater treatment plant (WWTP). One drinking water-irrigated plot was not fertilized (control). Five different treatments were applied to the soil: three organic mixtures (sewage sludge, sewage sludge mixed with pine bark and municipal solid waste with composted sludge) and a conventional fertilizer were applied to the four plots irrigated with drinking water. The last plot was irrigated with treated wastewater. The treatments were tested for their effect on plant growth and nitrate concentration in vegetable tissue. An increase in fresh weight in the lettuce was linked to the dosage of sewage sludge. The highest nitrate level was observed in the sewage sludge treatment in all crops and seasons, although, in general, all values were below the maximum limits established by the European Commission for nitrate content in fresh romaine lettuce. In the third crop season, a significant increase in nitrate content was observed in lettuce from organic treatments. Nitrate concentration in lettuce from irrigated treated wastewater was higher than control, although significant differences were not found.