Treated wastewater reuse in Puglia (Southern Italy):Demo and full scale activities

Alfieri POLLICE

alfieri.pollice@cnr.it

BackgroundFactors affecting water stress in Med countries:

1.Increasing coastal urbanization.2.Seasonal water stress (warmer season) due to simultaneous increase of:

• Tourism fluxes,• Agricultural requirements,• Uneven precipitations and higher temperatures (climate change),• Over-exploitation of natural resources.

% of available water yearly abstracted

Possible tools to tackle water stress include:• Water demand management

(water loss contrast, irrigation techniques, economic measures, training, etc.)• Water supply increase

(seawater desalination, wastewater reuse, rainwater harvesting etc.)

Yearly rainfall in the Med Basin 2

Reuse of treated wastewater in agriculture

Opportunities Continuous water supply; Safeguard of primary sources; Nutrients supply.

Risks Microbiological safety; Chronic effects on soils; Eutrophication of storage basins.

Are costs sustainable ? Are technologies adequate ? Are limits and regulations representative of local situations ? How stakeholders and final users can be involved ?

Questions

Background

3

Perceived complexity of TWWR (cross-sector issues concerning water, food, health and the environment) and need for some technical knowledge

Regulations not always suited to local contexts

Inadequate tariff policy (heavily subsidized conventional water resources) and limited financial capacity

Competition for conventional water resources and need to define priorities (need for planning supply and demand)

Risks of soil salinization, crops contamination, and pollution of water resources (need of monitoring proceduresand some analytical skills)

Public perceptioncould be highly negative, causing rejection of projects

Obstacles to TWWR in Med countriesBackground

4

Strongly ruralRuralModerately ruralUrbanStrongly urban

Rainfall (1960-2010)

Puglia: 600-650 mm/year136 m3/capita per yearabsence of permanent rivers/natural lakes

Cultivated 79%

Irrigated 19%

Other 21%

Land use

Puglia – Available water and land use

Wastewater treatment and effluent reuse

0

200

400

600

800

1000

1200

Agricultural Civil IndustrialDestination

Con

sum

ptio

n (M

m3 /y

)

External Resources (border regions) Regional Resources (groundwater)

Total Regional Water demand

1500 Mm3/y

Municipal wastewater potentially available for reuse in irrigation: • Total estimate 150 Mm3/year• Tertiary wastewater treatment plants currently available 90 Mm3/year

Further advantages:• Nutrient recovery• Continuous supply

Water demand in PugliaSavings on primary resources = 10%

Regional Water Plan of Puglia (2007)

Opportunities of reuse for irrigation in Puglia

Conventional wastewater treatment (activated sludge)

Primarysettling

Pre-treatment Activatedsludge

Secondarysettling

Rawwaste

Tertiarytreatments

Standards for discharge

Standards for reuseB) polishing

Water body(river/lake/sea)

A) upgrade or

Treated wastewater reuse in irrigation

Primarysettling

Pre-treatment

Activatedsludge

Rawwastewater

A) Upgrade of activated sludge process (Membrane Bioreactors – MBR)ultra FILTR

DISINF Effluent to irrigation

IRSA demo-scale activities: Surface filtration combined to biological processes

From treatment for effluent disposalto water production for irrigation

B) Polishing: Tertiary surface filtration processesDISINF

micro FILTR

ultra FILTRDISINFSe

cond

ary

efflu

ent

Efflu

ent

to ir

rigat

ion

• Study of processes based on low pressure surface filtration for the production of water suitable for irrigation, study of microbiological quality and nutrientconservation.

• IRSA’s main research projects on treated effluent reuse:2000-2002: POM - national,2002-2006: PON – Aquatec - national,2005-2008: FP6 – Reclaim Water – EU,2006-2009: FP6 – Aquastress – EU,2010-2012: PRIN - national,2011-2015: PON – Interra (also agro-industrial ww) - national,2012-2016: FP7 KBBE – Water4Crops - EU-India,2013-2016: FP7 Inno-Demo – Demoware - EU,2016-2018: Water JPI/ERANET Waterworks 2014 – MeProWaRe – EU.

IRSA activities on surface filtration for wastewater treatment and reuse

Case study 1 (Aquatec 2000/2006):Tertiary membrane filtration

Cerignola WWTP

50,000 P.E.

Test field2000 m2

Tertiary treatment (membrane) and

storage tanks

Pilot plant of 700 L/h

Membrane flux: 30 L/m2/hMembrane surface: 23,5 m2

Cerignola

Case study 1 (Aquatec 2000/2006):The pilot plant and the test field

2000 m2=16 parcels 5x24 mdrip irrigation (Soil Water Deficit 35%)

Storage tanks 30 m3

MBR

TEST FIELD irrigated with treated wastewater (MBR effluent) + E. coli

Persistence of E. coliin surface soil and on grass ?

E. coli (and NO3) transfer through soil layers… possibly to groundwater ?

SOIL COLUMNS irrigated with partially treated real wastewater

Case study 2 (PRIN 2010-2012):Fate of E. Coli in irrigation with treated wastewater

Pilot scale MBRQ=15 L/hSRT=25 days; HRT=6 hProd./Relax=3h/6min

Vergine et al. (2015) - Fate of the fecalindicator Escherichia coli in irrigationwith partially treated wastewater. WaterResearch, 85, 66-73.

WWTPoutlet

WWTPinfluent

2) GDF + UVSecondary effluent

1) IFAS-MBR + UVPre-screened wastewater

SETTLERS

ACTIVATED SLUDGE

SETTLERS

FILTR.CHLOR.COAG.-

FLOC.-SED.

Case study 3 (Water4Crops 2011/2016):IFAS-MBR and GDF for direct irrigation

Test field (3000 m2)Horticulture irrigated with treated effluents (including the WWTP outlet) and control (well water)

15mm

15mm

UV disinfection

0.5-1.0 m3/h Storage tanks (30m3)

UV on demand

(*) Integrated Fixed film-Activated Sludge Membrane BioReactor

Test field

Case study 3 (Water4Crops 2011/2016):IFAS-MBR(*) with on-demand UV disinfection

Open channel UV-C disinfection

n. 6 lamps(Hg vapor)

25m3/h UV on demand

Test fieldIN = secondary

effluent

Case study 3 (Water4Crops 2011/2016):GDF(*) with on-demand UV disinfection

(*) Gravity Disk Filter

GDF – Cloth filtration(polyester), pores of 20µm

Case study 4 (Demoware 2011/2016):Treated agro-industrial wastewater for irrigation

discharge

+ tertiarytreatment

irrigation

WWTPWW

Agro-ind. WW:• 12-15 mc/h• Quality + flowrate

fluctuations

Tertiary treatment:• Sand filtration• Membrane filtration• UV on-demand

Case study 5 (Fasano full scale plant):Tertiary treatment for water distribution to farmers

Initial configuration•Pre-chlorination (NaClO)•Clariflocculation (AlCl3)•Post-disinfection (O3/UV)

New configuration1. Simultaneous dosage of:•AlCl3 (clariflocculation)•NaClO or PAA (disinfection)•PAC (adsorption)2. Lamellar packs settlers

Irrigation network:•1500 hectares•30 km piping•48 farms

WWTP: 25.000 PE

Storage lake: 40.000 m3

Cost of tertiary treated water: 0,16-0,25 €/m3 (on the water bill)Cost of distribution: depends on volume, distance, irrigationtype (contracts with farmers).

Acquavivadelle Fonti

150-200 m3/h800 m3

900

m3well

Water types:•Well water;•Treated wastewater;•Blend of the two.

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Stakeholders: Farmers association, water utility, municipality.

Case study 6 (Meproware 2016/2018):Blending ww effluents with well water for irrigation

Next steps forward

• Demo/full-scale technology testing aimed at stakeholdersinvolvement and communication (also to the general public).

• Specific work on the INTERFACE between water production (WWTP) and water utilization (farmers).

• Developement of decision support systems (DSS) and mangement tools, identification of best management modelsfor local needs (private vs participated vs public, etc.).

• Dissemination of results towards policy makers.

THANKS FOR YOUR ATTENTION

alfieri.pollice@cnr.it