Workshop Wastewater REUSE From the research to the technological transfer within the Mediterranean Potenza, April 29-30 2013 Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems Donatella Caniani, Salvatore Masi, Ignazio M. Mancini, Carmen Lavinia Aridity affects large areas of the globe, i.e. 41% of the planet's land surface. Currently, dry regions are home to about 2.1 billion people. Recent studies show that by 2050, 2.3 billion more people than today are projected to live in river basins experiencing severe water stress (European Innovation Partnership Water, Strategic Implementation Plan). World map of aridity zones © CRU / UEA, UNEP / DEWA • Moreover, the Mediterranean Region, which comprises a transition between dry-sub-humid regions of northern croplands to hyper-arid southern desert (Saharan-Arabian deserts), is recognised among those most affected by drought that can speed up land degradation. Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 • The consequences are rapid reduction of usable arable lands, quick decrease of the land productivity, widespread ecosystem degradation and, in turn, higher risk of desertification. • Desertification is a common threat to the Mediterranean basin. It is estimated that at least 11% of the EU population and 17% of its territory have been affected by water scarcity to date. • Moreover, as reflected by the Blueprint to safeguard Europe's water resources, almost half of Europe’s freshwaters are at risk of not achieving good ecological status, the main objective of the EU Water Framework Directive by 2015, with adverse effects on biodiversity and public health. Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 • The use of non-conventional water resources, through recycling and reuse of water, helps to provide water in a safe, available and affordable way, reducing energy consumption, costs of treatment, and environmental impacts. The reuse of water, therefore, is an essential component in the sustainable management of water. • Water recycling and reuse should be considered as the core of an integrated water management approach to save costs, recover materials and demonstrate environmental stewardship. Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 The main objective of the present work aims at demonstrate how the reuse of wastewater may have, among other positive effects, also the improvement of the quality of surface waters, by the subtraction of the polluting loads that do not reach surface water. In order to achieve this objective, a scenario analysis was carried out to evaluate the water quality at the river basin scale of the main rivers of the Region of Basilicata (Southern Italy). We developed a new methodology, valid for every kind of basin and based on three hydrological regimes, to estimate the response of the rivers, under each management scenario and so obtain the environmental water quality status for the actual river conditions and after the measures of mitigation. Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 At national and international level, there are interesting applications of scenario analysis by modelling. The QUAL2E model is the most widely applied by environmental agencies around the Azzellino et al. (2006) and Salvetti et world for studying water quality and is used in different settings for different parameters al. (2006) apply the QUAL2E and the (Marsili-Libelli et al., 2004; Muhammetoglu et al., 2005; Azzellino et al., 2006; Salvetti et al., SWAT models to evaluate the source 2006; Paliwal et al., 2007). apportionment of river pollution as required from the WFD. Dry and wet Marsili-Libelli et al. (2004) adopt the scenarios are considered to evaluate Drivers-Pressures-States-Impacts- river flow conditions without the Responses (DPSIR) model introduced by analysis of the average flow period. the WFD. The study proposes the construction of an integrated software In the work of Azzellino et al. (2006), tool whereby current quality data can be a sort of calibration is obtained by used to produce quality scenarios and feeding the model with indirect apply the DPSIR model. The study is estimates of input loads and by conducted at a river basin scale (seasonal comparing simulated data of flow scenarios are considered) and the MPL and water quality parameters with parameter is evaluated. median trend of the measures. The calculation of median is chosen for the distribution skewness of the water quality measurements. The simulation corresponds roughly to consider the dry weather conditions and allows grossly the validation. Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 The QUAL2E model was calibrated for the dry season to simulate BOD and DO profiles for a stretch of the river Yamuna.Two sets of data are used for calibration and validation for the low flow period (Paliwal et al., 2007). In the scenario analysis the identified interventions can cover point sources and diffuse sources of water pollution (Kronvang et al., 1999; Muhammetoglu et al., 2005; Kneis et al., 2006; Marsili-Libelli and Giusti, 2008) or only point sources (Marsili-Libelli et al., 2004; Xenarios and Bithas, 2007; Paliwal et al., 2007) or only diffuse sources, as in many studies that are focused on scenario analysis to evaluate different land use management alternatives (Coiner et al., 2001; Vaché et al., 2002; Kersebaum et al., 2003; Nassauer and Corry, 2004; Santelmann et al., 2004; Jessel and Jacobs, 2005; Kersebaum et al., 2006; Bongartz et al., 2007; Volk et al., 2007). Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 suitable to the study Analysis conducted of stream water at a river basin scale quality that not correspond Evaluation for each studied necessary to seasons and river of three hydrological cover different periods of conditions the ye a r, in dependence (low, medium and high flows) on climatic conditions This allowed a Analysis applied validation of the to five river basins environmental models Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 Bradano Basento Cavone Agri The hydrology of Basilicata river basins ensures a good availability of water Sinni resources, which are accumulated in Theseveral Region reservoirs of Basilicata. The supplyis characterised sources are by aable complex to ensure hydrographic an annual network availability focused of onabout five 1 billionmain ofrivers m3. The called water: Bradanoresource, isBasento shared, Cavone by ,several Agri and uses Sinni: ,drinking, flowing Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impactintoirrigation, the on Ionicwater hydroelectric Sea and whose and in basins small cover part quality in river systems, Potenza 29-30 April 2013 industryabout 70. % of the regional territory. ü High ecological status Bradano üGood ecological status üModerate ecological status üPoor ecological status üBad ecological status Basento Cavone Agri It is interesting to observe the measured and actual ecological status of the rivers, Sinni as indicated by the biological indicators and macrodescriptors. The north-eastern rivers Bradano, Basento and Cavone are Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impactin onthe water worst conditions with bad and quality in river systems, Potenza 29-30 April 2013 poor ecological status Soil and Water Assessment Tool (SWAT) model (Di Luzio et al., 2002), which simulates the water, pollutants and sediment contributions at the basin scale and is used to estimate agricultural, livestock and tributaries loads. The SWAT model outputs were used as inputs to QUAL2K model. River water quality model QUAL2K (Chapra et al., 2006) Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 The SWAT model (Neitsch et al., 2001) is a semi-distributed and continuous time model that operates on a daily time SWAT SWATstep to estimateallows modellingthe effects ofthe entirewater managementprocess andof the pollutanthydrological releases cycle, in streamincluding systems.rainfall,The model allowsevapo -thetranspiration, watersubdivision withdrawls, of watersheds intoand groundwatersmaller subwatersheds recharge., which are then subdivided into multiple Hydrologic Response Units (HRUs) that create separate and unique combinations of soil and land cover properties in subbasins. Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 The Cavone basin has the modest extension of 675 km2 and is 49 km long . The morphology is hilly with the exception of the mountainous upper part and the eastern portion. Summer outflows are close to zero, due to the scarce rainfalls and the lack of wellsprings. Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water