WASTEWATER ANALYSIS FOR THE REUSE IN THE AGRICULTURAL PRACTICE

Aim: Treated wastewaters are a new resource as a low-cost alternative to conventional supplies for agricultural irrigation; this reuse improves the urban and periurban agriculture despite the health and environmental risks associated with this practice. In fact, the wastewater reuse if not correctly managed carries a potential public health risk when directly reused to irrigate crops that are commonly eaten without cooking (e.g., vegetable crops as tomatoes and most fruit crops) (WHO, 2006). In this work, the urban wastewater quality coming out from the treatment plant of the Syracuse city (Sicily- Italy) for its reuse in agriculture was assessed. Methods: Samples were collected from outlet collector of this treatment plant and subjected to chemical and microbiological analysis according to the Italian wastewater regulation for agriculture reuse (DM 185/2003). All analysis were conducted through appropriate analytical techniques by official Italian analysis methods APAT/CNR/IRSA. Results: Results obtained revealed wastewaters does not conform to reuse because the values of COD, BOD, ammonia nitrogen, chlorides, mineral oils, surfactants and Escherichia coli, exceeded the limits required by DM 185/2003. These results give us an indication for better dimension wastewater volumes to plants reception capacity by a prevision of m3/h of wastewater in input on plant and empowerment of plant receptivity. Conclusion: Our results revealed the importance of a better use of techniques for reducing organic charge as sedimentation, oil removal and oxidative interventions. Despite some results exceeded required limits, if good conducted, these improvements will permit easily to overcome these problems. A better management wastewater volume input to the treatment plant and the improvement of techniques for organic substances reduction will allow an increased availability of freshwater for agricultural irrigation with a positive economic impact for Sicilian region. Moreover, a tertiary treatment unit, made of a microfiltration system followed by an UV device, is under construction in the studied. This system will allow the improvement of the E. coli reduction, reaching the requested law limits for a secure and hygienic wastewater reuse. In sum, the wastewater represent today a resource of growing global importance. Tthe extended reuse of this reclaimed water for irrigation use could contribute considerably to the reduction of water stress in Sicily, but its use in agriculture must be carefully managed in order to preserve the economic and social benefits while minimizing the possible risks for humans and environmental health.