Recycling : Reduce, Reuse and Recycle

The STO3RE project Objective was to demonstrate a new concept of Waste Water Treatment Plants, promoting highadded value uses for sewage sludge and agroindustrial co-substrates, through an innovative Join Management technique, protecting waters against pollution (caused by nitrates), avoiding eutrophication episodes due to diffuse sources and producing energy to be self-sustained. In this work the applicability as soil organic amendment of the digested sludge obtained from the application of this innovative and cost effective technology (anaerobic digestion two phase temperature coupled to ozone oxidation) was evaluated. Two different plant types were selected for testing: i) young and 10 years old almond trees (GF677 almond rootstock, a peach x almond hybrid with good behavior in dry conditions) and ii) Cynara cardunculus, which can be grown in hot, dry Mediterranean climates and it is of use in ecosystem restoration and biomass. Treatments were applied in triplicate to 100 m2 plots at rates of 170 kg N/ha/year (dose 1) and 100 kg N/ha/year (dose 2). Non-amended plots and plots amended with conventional sewage sludge were used as controls. Plant yield and different soil physical, chemical, biochemical and microbiological parameters were determined