Environmental Aspects of the Reuse of Treated Wastewater: Impact on Water Quality in River Systems

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: impactirrigation,into 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 quality in river systems, Potenza 29-30 April 2013 Input data

Hydrografic basin DEM

SWAT Database River network

Land cover Parametrization

Pedology HRUs definition RUN Calibration

Output Maps Climatic time series SWAT Model

ArcGIS Donatella Caniani, Environmental aspects of the reuse of treated wastewater:Output impact on tables water quality in river systems, Potenza 29-30 April 2013 and graphs Rainfall Temperatures (max and min) Evapotranspiration Wind velocity Torre Accio Relative humidity Stigliano Craco Solar radiation Peschiera

Terra Mont.

Tursi Cavone SWAT is provided with a weather generator thatSS106 allows to simulate long periods even if not covered by observations

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 The outputs provided by the SWAT model were used as diffuse source of pollution inputs to the QUAL2K model

MODEL SEGMENTATION. UsedThe major to evaluate hypotesis the ofconcentrations the QUAL2K ofmodel are: QUAL2K segments the system into river reaches, which, in turn, are macrodescriptors• monodimensional along hydraulic the river network; through subdivided into discrete elements, considered as completely mixed reactors, •equationssteady state;that describe the development with uniform hydraulic, geometrical and biochemical characteristics •of chemical,daily heat biologicalbudget; and physical processes • daily kinetics of the water quality descriptors; • subdivision of the contaminant loads in point sources (wastewater treatment plants) • and diffuse sources (agricultural and livestock loads).

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 MassGraphical balance representation of the equations used in the model QUAL2K

Aeration Norg s4 b SOD 3 K4 The balance is valid for everyK 2river element with the hypothesis of

(F s 1 3 NH CBOD a steady) state4 (∂C/∂t = 0). K3 K1

b1 a b¶C ( DLAx 5××¶ 1 ) 1 ¶x Dissolved1 oxygenAx ××¶ Cu )( dC s × - × =++ P-disc Ax ¶x ¶x 0 s NO Ax dt V5 2 b4 a b where: 6 2 b2 a3m a4r 2 Ax is the cross-sectional area (m ) 2 s2 P-org DL is the diffusion coefficient (m /s) NO 3 C a1(1-F) is the concentration3 of the considered parameter (kg/m ) u is the mean flowa speed1m (m/s) s are the sources and/or lossesAlgae of the parameter due to reactionsa m anda transportr a r 2 2 mechanisms (kg/s) 1 3 V is the volume (m ). s1

Kinetic processes are dissolution (ds), hydrolysis (h), oxidation (ox), nitrification (n), denitrification (dn), photosynthesis (p), Donatellarespiration Caniani (r), excretion, Environmental (e), death aspects(d), respiration/excretion of the reuse of treated (rx). Mass wastewater: transfer impactprocesses on arewater reaeration (re), settling (s), qualitysediment in oxygenriver systems demand, Potenza (SOD), 29sediment-30 April exchange 2013 (se), and sediment inorganic carbon flux (cf). Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 Outflow

Input data to 250 QUAL2K Calculated with Low flow regime 200 SWAT

150 Medium flow regime Diffuse pollutant loads Portate (m3/s) 100 High flow regime

=44.9 m3/s

0 =3.3 m 0 50 100 150 200 250 300 350 Wastewater treatment plantsTempo (giorni) =0.3 m

DonatellaFlow Duration Caniani Curves, Environmental or flow monthly aspects data of in the the reuse sampling of treated stations wastewater: provided byimpact the Basin on water Authority of the Basilicata region quality(AdB, 2006) in river were systems analysed, Potenza to calculate 29-30 April the duration2013 of the hydrological regime in the year and the headwater characteristic flow CBOD Organic Ammon Nitrate Organic Inorganic Diffuse Sub fast N N N P P Inflow Detritus

3 mgO2/L mgN/L mgN/L mgN/L mgP/L mgP/L m /s mgD/L Diffuse pollutant loads

1 0.0000 0.0000 19.9801 0.0000 0.0000 2.8797 0.0051 0.0138 2 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0023 0.0216 3 0.0000 0.0000 19.9866 0.0000 0.0000 2.8162 0.0214 0.0125 4 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0038 0.0115 5 0.0000 0.0000 8.4742 0.0000 0.0000 1.1651 0.0269 0.0127 6 0.0000This loads0.0000 were 0.0000calculated 0.0000 with SWAT0.0000 for each0.0000 of the0.0051 three 0.0095 7 0.0000hydrological 0.0000 regimes:11.8426 0.0000 0.0000 3.1884 0.0341 0.0135 8 0.0000- Low flow0.0000 0.0000 0.0000 0.0000 0.0000 0.0067 0.0091 9 0.0000- Medium 0.0000 flow 10.4477 0.0000 0.0000 1.2079 0.0440 0.0133 10 0.0000- High flow0.0000 0.0000 0.0000 0.0000 0.0000 0.0014 0.0271 11 0.0000 0.0000 0.0000 13.5184 0.0000 0.6533 0.0537 0.0186 12 0.0000 0.0000 17.9362 0.0000 0.0000 2.2984 0.0578 0.0137 13 0.0000 0.5272 40.3959 393.7232 0.6463 688.010 0.0317 0.0071 14 0.0000 0.0000 16.0839 0.0000 0.0000 1.6084 0.0910 0.0116 15 0.0000 0.5703 39.9414 399.3196 0.8544 6.3503 0.0123 0.0044 16 0.0000 0.0000 0.0000 14.1280 0.0000 1.0542 0.1065 0.0110 17 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 18 0.0000 0.0000 9.6869 0.0000 0.0000 0.9163 0.1061 0.0115 Donatella Caniani, Environmental19 0.0000 aspects0.0000 of the0.0000 reuse of treated0.0000 wastewater:0.0000 impact0.0000 on0.0037 water 0.0117 quality in river systems, Potenza 29-30 April 2013 SENSITIVE AREAS

Sesitive areas cover about 50% of the territory. 92 WWTPs are located and dischardge in sensitive areas · There are 252 · WWTPs.

The inputs loads for a wastewater treatment plant are evaluated considering a per capita contribution equal to: •150 gr/Ehs d for chemical oxygen demand (COD); •13 gr/Ehs d for total nitrogen; •2 gr/Ehs d for total phosphorus.

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 WWTPs

The following reduction percentages for pollutants Actual were considered: : situation 90% BOD 95% COD 50% TN 25% TP

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 Simulation from the 1st of January 1996 to the 31st of December 2006

300

250 Calibration period From the 1st of January 2001 st 200 To the 31 of December 2004

150

Deflussiobserved osservati Deflussisimulated simulati

Portata (mc/s) 100

50 Validation period From the 1st of January 2005 0 st 10/1/2000To the 4/19/2001 31 11/5/2001 of December 5/24/2002 12/10/2002 2006 6/28/2003 1/14/2004 8/1/2004 2/17/2005 9/5/2005

-50 Tempo (giorni)

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 DO DO_magra BOD 12 14 curva_taratura 12 10 misura+intervallo_confidenza_CVRR01

10 misura+intervallo_confidenza_CVRR02 8 8

DO_mg/l 6 6 BOD_mg/l 4 curva_taratura 4 2 misura+intervallo_confidenza_CVRR01 misura+intervallo_confidenza_CVRR02 2 0 80 60 40 20 0 0 Km 90 80 70 60 50 km 40 30 20 10 0

NH4 NO3 TP 3000 12000 1400 curva_taratura curva_taratura curva_taratura 1200 2500 10000 misura+intervallo_confidenza_CVRR01 misura+intervallo_confidenza_CVRR01 misura+intervallo_confidenza_CVRR01 misura+intervallo_confidenza_CVRR02 1000 misura+intervallo_confidenza_CVRR02 2000 8000 misura+intervallo_confidenza_CVRR02 800 1500 6000 600 Ptot_microg/l NH4_microg/l 1000 NO3_microg/l 4000 400

500 2000 200

0 0 0 90 80 70 60 50 km 40 30 20 10 0 90 7080 60 km 4050 30 1020 0 90 80 70 60 50 km 40 30 20 10 0

The QUAL2K model was calibrated for the actual scenario and the low flow regime varying the coefficients that regulate chemical variables so that the daily mean trend of the macro-descriptors interpolates the mean value of monthly samplings regarding the low flow, in the quality monitoring stations of ARPAB. In addition to the mean sampling value, the confidence interval expressed as standard deviation from the mean value is reported Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 BOD_piena 7 DO_piena curva_taratura 14 6 misura+intervallo_confidenza_CVRR01 12 5 misura+intervallo_confidenza_CVRR02

10 4 8 DO_mg/l

BOD_mg/l 3 6 curva_taratura

2 4 misura+intervallo_confidenza_CVRR01

2 1 misura+intervallo_confidenza_CVRR02 0 0 80 60 40 20 0 Km 90 80 70 60 50 40 30 20 10 0km

NH4_piena Ptot_piena 1400 700 curva_taratura curva_taratura 1200 600 misura+intervallo_confidenza_CVRR01 misura+intervallo_confidenza_CVRR01 500 1000 misura+intervallo_confidenza_CVRR02 misura+intervallo_confidenza_CVRR02 400 800

300 600 Ptot_microg/l

NH4_microg/l 200 400 100 200 0 0 80 60 40 20 0 km 90 80 70 60 50 40 30 20 10 0km

The validation procedure of the model was made considering the actual scenario and the average and high flow conditions.

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 Cavone basin

Flow regime low, medium all wastewater treatment plants work and imposition of concentration limit for BOD, Scenario 1 (plants with EHs >2000) validity of scenario 1 and addition of a consortium plant that includes the wastewater Scenario 2 treatment plants of Accettura, San Mauro Forte, Stigliano and Oliveto Lucano and imposition of concentration limit for BOD of the consortium plant validity of scenarios 1 and 2 and TWW reuse for the plants with EHs>2000 (included Scenario 3 consortium plant) validity of scenarios 1 and 2 and 3 and addition of a consortium plant for Garaguso and Scenario 4 reuse of its TWW

Flow regime high all wastewater treatment plants work and imposition of concentration limit for BOD, Scenario 1 (plants with EHs >2000) validity of scenario 1 and addition of a consortium plant that includes the wastewater Scenario 2 treatment plants of Accettura, San Mauro Forte, Stigliano and Oliveto Lucano and imposition of concentration limit for BOD of consortium plant and addition of a consortium plant for Garaguso

A set of management scenarios was defined for each river basin. The “zero option” represents the actual situation. The SWAT and the QUAL2K models were used to simulate the system’s response for each scenario, during the low flow, medium flow and high flow regimes.

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 NO3BODNO3_MAGRA (low (lowBOD_MAGRA flow) flow) limite_stato_buono BOD (mg/l) NH4NH4_MAGRA (low flow) scenario_attualelimite_stato_buono NO3 (mg/l) scenario_1 NH4 (mg/l) scenario_attualelimite_stato_buono 600012 scenario_2 scenario_1scenario_attuale 3000 scenario_3 scenario_2scenario_1 scenario_4 scenario_3scenario_2 500010 scenario_3 2500 scenario_4 scenario_4

400020008

300015006

1000 2000 4

500 1000 2 0 x 0 80 60 40 20 0 (Km) 0 x x 102030405060708090 0 (Km) 80 60 40 20 0 (Km)

The graphs show an example of the outputs obtained along the river from the QUAL2K model for 5 different scenarios, during low flow regime, and for BOD5, NO3, Ammonium. The fourth scenario involves the reuse of all wastewater during periods of low flow. The same procedure was repeated for all watersheds and all flow regimes.

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 The fundamental elements of the proposed method are: • the decision matrix, • the entropy based method used to weight criteria • the technique used to select the best scenario

In order to select the best scenario, the following model of multi-criteria analysis has been developed. The main challenge in ranking management scenarios is the bias preservation. In order to achieve this, it is necessary to obtain the criteria weighs in an unbiased way, before multi-criteria analysis is performed.

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 21 www m )..(

21 .. CCC m .. rrrS M = 12111 1m 22212 .. rrrS 2m ......

nnn 21 .. rrrS nm S = scenarios C = criteria (environmental impact indices of the river water quality) w = weighs of criteria

rij = scores obtained by the scenarios with respect to the different criteria n is the number of criteria and m is the number of scenarios

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 In literature, there are several useful criteria, such as “law criteria”, that enable to evaluate the concentration shift of the river water quality parameters from the threshold values, criteria that concern the shift of the maximum or the mean value, criteria based on the law threshold level shift, etc. Weaknesses: These indexes do not take into account the cases in which all or some of the simulations produce output values always lower than the values of legislation. They also do not take into account the duration and, therefore, the extent of the episode.

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 700 In order to take into account curva_taratura the entity and the duration 600 of the possible water quality misura+intervallo_confidenza_CVRR01 alteration, integral indexes have been developed. 500 misura+intervallo_confidenza_CVRR02 The integral indexes can be obtained by calculating the 400 area under the curve that represents the evolution of 300 the water quality parameters Ptot_microg/l concentration along the 200 river. Therefore, this environmental impact 100 indicators have a double role: measuring the effects 0 of scenarios and serving as 80 60 40 20 0 km criteria for ranking scenarios in the multi-criteria analysis.

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 Entropy is generally considered as an uncertainty measure. Considering the scores of the scenarios as emitters of information about the relative importance of each criterion, the entropic method allows the evaluation of each information source and the assessment of criteria weighs 1211 .. xxx 1m (w1, w2, …, wm). -1 .. xxx é n ù 2221 2m = = ijij êå kj ú ,...2,1, nirrx X = ..... ë k =1 û ..... additive normalization nn 21 .. xxx nm

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 Information contained in the matrix X is considered to be the emission power of each criterion and it can be used to

estimate the entropy value ej:

Entropy

n ij -= å ln ijij jxxke = ,...2,1, m i=1

where the constant, k = 1/ln(m), guarantees that:

e j ££ 10

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 The divergence of information of each criterion can be calculated using the following equation:

Degree of divergence

j j =-= mjef .,...,2,1,1

It implies that the higher is the divergence, fj the more important is the relative criterion for the analyzed problem. Therefore, if all alternatives will obtain similar scores for a given criterion, this criterion will have less weight.

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 An additive normalization will give the final weights of all criteria

Weights of criteria

-1 é m ù = êå kjj ú = mjffw .,...,2,1, ë k =1 û

The entropy method can be defined as an objective method, since the weighs of criteria are obtained from the decision matrix. The procedure used for retrieving the best scenario is as ‘ideal-point’ method that consists in defining it as the one that shows the shortest distance from the “ideal” solution and the longest distance from the “negative ideal” solution. Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 Cavone basin Best scenario

Flow regime low, medium imposition of concentration limit for BOD, addition of a consortium plant that Scenario 4 includes the wastewater treatment plants of Accettura, San Mauro Forte, Stigliano and Oliveto Lucano, TWW reuse for the plants with EHs>2000 (included consortium plant) and addition of a consortium plant for Garaguso and reuse of its TWW

Flow regime high imposition of concentration limit for BOD and addition of a consortium plant Scenario 2 that includes the wastewater treatment plants of Accettura, San Mauro Forte, Stigliano and Oliveto Lucano and imposition of concentration limit for BOD of consortium plant and addition of a consortium plant for Garaguso

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 •The worst qualitative conditions emerge for Bradano basin, Cavone and Basento river basins, Agri is in an intermediate condition, Sinni basin has the best situation. •Concerning the actual condition, on all basins, the macro-descriptor which has the worst environmental status is ammonia-N then total phosphorus and dissolved oxygen, BOD has the best condition. •Bradano is far from natural conditions especially with regard to ammonia-N, total phosphorus and BOD, although BOD reaches the good status for medium and high flow. Dissolved oxygen has, in general, the better condition with the prevalence of the moderate status. •Cavone river shows the greater problems related to ammonia-N and total phosphorus, BOD follows. Dissolved oxygen shows the favourite conditions with the attainment of the good environmental status for medium and high flow. •The Sinni river presents a satisfactory condition with the achievement of environmental quality objective for BOD along all the river, dissolved oxygen, ammonia-N and total phosphorus.

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 •The multi-criteria analysis allowed us to highlight which integral index is the most important criterion • NH4 integral index appears to be moderately important in all the river flow regimes and for all the rivers. •In the case of low flow regimes, for Bradano river, DO is the most important parameter, with the highest weight. While, for the Sinni river, the most important criteria are BOD and DO respectively. •In the case of medium flow regimes, the Cavone river has the same behavior, while for Bradano the most important criterion is BOD. •For the Basento river, for medium and high flow regimes, the NH4 integral index appears to be the most important criterion. For the low flow regime, the weights of all the criteria are similar.

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 •The suggested interventions for Agri basin are: the operation of all wastewater treatment plants, the enforcement of discharge limits in sensitive areas, the application of the code of good agricultural practice, the wastewater reuse and the release of a greater flow downstream of the dams. •To improve the qualitative and quantitative conditions of Bradano it is necessary that all the wastewater treatment plants work correctly, the TWW reuse, the respect of agricultural good practice and the release of greater flow by dams. •In the Cavone basin it is necessary that all wastewater treatment plants work in order to obtain concentrations of BOD below the threshold values for WWTPs, the wastewater reuse, the construction of consortium plants that achieve the reduction of management costs and depurative efficiencies unreachable with small plants. •For Sinni it is necessary that all wastewater treatment plants work and upstream the TWW reuse. •By establishing a scale of priorities, rivers that require protection interventions more urgent are in order: Bradano, Basento, Cavone, Agri and Sinni.

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 •For each river the different behaviour of water quality parameters in dependence on hydrological regime emerged. Therefore, the regime distinction was crucial for understanding the preliminary river environmental quality status. •In general for Basilicata basins the greater pollution is produced from ammonia-N. BOD meets the environmental quality objective several times, changing hydrological regimes. •The results demonstrate how the reuse of wastewater helps the improvement of the quality of surface waters, by the subtraction of the polluting loads that do not reach surface water.

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 t t 0 å( day surf a seep ----+= QwEQRSWSW gw ) i=1

[mm SWt : contenuto finale di acqua nel suolo H2O] [mm SWo :contenuto iniziale di acqua nel suolo giornaliero H2O]

T : tempo [giorni] [mm Rday : ammontare della precipitazione nel giorno i-esimo H2O] [mm Qsurf : ammontare del deflusso superficiale nel giorno i-esimo H2O] [mm Ea : ammontare dell'evapotraspirazione nel giorno i-esimo H2O]

: ammontare di acqua entrata nella zona vadosa dal profilo [mm Wseep del suolo nel giorno i-esimo H2O] [mm Qgw :ammontare del flusso di ritorno nel giorno i-esimo H2O]

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 2 procedimento del Curve ()- IR aday Qsurf = Number dell’SCS ()aday +- SIR (Soil Conservation Service)

æ1000 ö TERMIN S 4,25 ç DESCRIZIONE-×= 10÷ DIMENSIONE E è CN ø Ammontare del deflusso o Q mm H O surf eccesso di pioggia 2

Rday Altezza di pioggia giornaliera mm H2O sottrazione iniziale che include: immagazzinamento superf., I mm H O a intercezione, e infiltrazione 2 prima del deflusso SS parametro di ritenzione

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 • Introduction • Objective • Materials and Methods: Scenario analysis at river basin scale • Entropic method of multicriteria analysis • Results • Conslusion

Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, Potenza 29-30 April 2013 Bradano basin Best scenario

Upstream

Flow regime low

Scenario 3 TWW reuse for all wastewater treatment plants

Flow regime medium

Scenario 3 TWW reuse for all wastewater treatment plants

Flow regime high

Scenario 1 all wastewater treatment plants working

Downstream

Flow regime low

Scenario 2 TWW reusefor all wastewater treatment plants

Flow regime average

Scenario 2 for all wastewater treatment plants

Flow regime high Donatella Caniani, Environmental aspects of the reuse of treated wastewater: impact on water quality in river systems, PotenzaScenario 29-30 1 April 2013all wastewater treatment plants working