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1
REUSE OF TREATED MUNICIPAL
WASTEWATER AS A SUSTAINABLE
APPROACH TO IRRIGATION AND
FERTIRRIGATION IN MEDITERRANEAN
COUNTRIES: A CASE STUDY
Alfieri POLLICE,
Pompilio Vergine,
Antonio Lonigro,
Carlo Salerno,
Giovanni Berardi
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
2
1. Water needs in Apulia region
2. Treatment schemes for wastewater reuse
3. Case study description
4. Performance of the pilot scale IFAS MBR
5. Agronomic results
Presentation outlines
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
3
Apulia - Available water and
land use
Strongly rural
Rural
Moderately rural
Urban
Strongly urban
Rainfall (1998)
Apulia: 600-650 mm/year
136 m3/capita per year
absence of permanent rivers/natural lakes Cultivated
79%Irrigated
19%
Other
21%Land use
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
4
Apulia - Potential treated
wastewater reuse in irrigation
0
200
400
600
800
1000
1200
Agricultural Civil Industrial
Destination
Co
ns
um
pti
on
(M
m3/y
)
External Resources (border regions)
Regional Resources (groundwater)
Total Regional
Water demand
1500 Mm3/y
Municipal wastewater potentially available for reuse in agriculture:
• Total estimate 150 Mm3/year
• Already or almost available (tertiary treatment plants) 90 Mm3/year
Other advantages:
• Nutrients
• Continous availability
Water demand in Puglia
10% savings of
primary water source
Piano di Tutela delle Acque della Regione Puglia (2007) [transl.: Regional Water Protection Plan]
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
5
Treated wastewater reuse
for irrigation
Opportunities
• Continuous water supply;
• Savings on primary
sources;
• Nutrients.
Risks
• Microbiological safety;
• Chronic effects on soils;
• Eutrophication of storage
basins.
Is the cost sustainable ?
Are technologies adequate ?
Are limits and regulations representative of local situations ?
How stakeholders and final users can be involved ?
Questions
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
6
How to choose the treatment
scheme for agricultural reuse 1/2
Conventional wastewater treatment plant
Primary settling
Pre-treatments
Activated sludge
Clarifier
Raw sewage
Tertiary treatment
Discharge
standards
Agricultural reuse
standards
Tertiary
treatments
Waterbody
upgrade
or
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
7
How to choose the treatment
scheme for agricultural reuse 2/2
Suspended solids
Microrganisms
Toxic compounds (metals/organics)
Nutrients (N, P)
Clariflocculation, Filtration (GMF), Membrane filtration
Disinfection, Membrane filtration
Act. carbon adsorption, Clariflocculation
Biological treatments, Ammonia stripping, Chemical precipitation
Pipe clogging, Accumul. on soil
Hygienic safety
Accumulation in soil and crops
Eutrophication of storage basins
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
Parameters Concerns Technologies
8
Possible wastewater treatment
schemes
POND STABILIZ. POND
d) DISINF
micro FILTR
Tertiary treatments
Application field of IRSA’s pilot tests:
surface filtration combined with
biological treatment (MBR)
c) WETLAND POND
DISINF
e)
ultra FILTR
DISINF
b) DISINF
a) COAG FLOC SED FILTR DISINF
f)
Primary settling
Pre-treatments
Activated sludge
Raw sewage
WWTP upgrade: ultra FILTR
DISINF
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
9
The experimental installations
WWTP influent
WWTP outlet
PP) IFAS/MBR + UV
Treatment of pre-
screened municipal WW
Test field (3000 m2)
Horticulture irrigated
with treated effluents
(including the WWTP
outlet) and control
(well water)
SETTLERS
ACTIVATED
SLUDGE
SETTLERS
FILTR. CHLOR.
COAG.-
FLOC.-SED.
WWTP
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
10
Pilot plant description
irrigation 15mm
15mm
Integrated Fixed film-Activated Sludge Membrane BioReactor (IFAS-MBR)
UV disinfection
0.3-0.8 m3/h reservoir (30m3)
UV on
demand
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
11
IFAS-MBR performances
Interruptions (carriers clogging) did not affect COD removal, but affected
nitrification. However, nitrification was always recovered in less than
one week after each stop.
0
20
40
60
80
100
29/08/12 26/01/13 25/06/13 22/11/13 21/04/14 18/09/14
Re
mo
va
l (%
)
COD
TKN
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
12
IFAS-MBR + UV: pathogen
indicators removal
UV
disinfection 0÷101 0÷103
permeate storage tank
E.Coli (CFU/100mL)
IFAS-MBR 0÷101
out IFAS-MBR
E. Coli (CFU/100mL)
out UV
E. Coli (CFU/100mL)
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
13
Water sources adopted for
irrigation (2-years averages)
Parameter Control WWTP
effluent PP
effluent Local limits
for reuse
EC (µS/cm) 888±420 989±170 764±88 3000
pH (-) 7.5±0.3 7.7±0.2 7.1±0.5 6.0-9.5
COD (mgO2/L) <15 67.1±55.4 19.5±5.4 100
NH4+ (mgN/L) <2 <2 2.6±7.0 2
NO3- (mgN/L) 1.5±1.5 6.4±5.6 29.2±17.1 35(*)
Total Phosphorus (mgP/L) 0.4±0.7 4.2±5.5 8.1±4.3 10
TSS (mg/L) <2 4.8±1.0 <2 10
Free Chlorine (mg/L) <0.2 <0.2 <0.2 0.2
SAR (-) 0.9±0.8 1.1±0.1 0.8±0.1 10
E. coli (CFU/100mL) 0±0 872±1292 0±1 10(**)
Salmonella spp Absent Absent Absent Absent (*) Limit related to Total Nitrogen. (**) Limit that has to be respected by 80% of the samples (maximum value=100 CFU /100mL).
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
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Test field
Apr-Jun 2013 Lettuce Cv. Canasta - Single rows, 6.7 plants/m2 Drip irigation - Irrigation threshold: 10 mm ETc
Sept 2013-Jan 2014 Fennel Cv. Archimede - Single rows, 10 plants/m2
Drip irrigation - Irrigation threshold: 16 mm ETc
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
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Agronomic results - productivity
0
50
100
150
200
250
300
350
0
10
20
30
40
50
60
lettuce control
lettuce WWTP
lettuce PP1
fennel control
fennel WWTP
fennel PP1
N a
nd P
sup
ply
(k
g/h
a)
Cro
p y
ield
(t/h
a)
crop yield N from fertilization N from irrigation P from fertilization P from irrigation
0
700
1400
2100
2800
3500
0
30
60
90
120
150
Irrig
ation,
Rain
fall
(m3/h
a)
Gro
win
g
season (
d)
Growing season Rainfall Irrigation
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
16
Agronomic results – Faecal
indicators at harvesting time
Escherichia coli
Water
(CFU/100mL)
Soil
(CFU/1g)
Edible parts
(CFU/1g)
Fennel
Control 0 0 0
WWTP 102-103 0 0
PP 0-10 0 0
Lettuce
Control 0 0 0
WWTP 102-103 <1 4
PP 0-2 0 0
Salmonella: always absent in water, soil and edible parts
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
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Conclusions
Operating the WW treatment (biological process) for partial nitrogen
removal (nitrification) allowed the supply of a consistent fertilization
contribution with the irrigation water.
This had positive effects on yield and growth rate of both lettuce and
fennel, without affecting the quality of crops.
Two treatment schemes applied to the same municipal WW
Significant differences in terms of suspended solids and faecal
indicator removals. The pilot plant, based on ultrafiltration and UV
radiation, had better performance for producing water suitable for
agricultural reuse (e.g. complying with local laws).
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
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Thanks for your attention
Acknowledgements:
European Commission FP7 KBBE
MIUR (Ministero dell’Istruzione dell’Università e della Ricerca)
www.pon-interra.it Italian National project
www.water4crops.org Euro-India collaborative project
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
20
IFAS-MBR operation
Problems related to the presence of the carriers
Clogging in several points of the plant required changes in piping
and pumping in the first months after start-up.
Steady state conditions for biological processes were reached only
some months after start-up.
Interruptions of the pilot plant operation caused membrane fouling
and a loss of membrane productivity (from 800 L/h to 300 L/h).
The biofilm attached to the carriers decreased consistently with the
flow rate, indicating that the biofilm growth is significantly limited
under very low organic loading rates (0.15 gCOD/gVSS/d).
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015
21
Agronomic results
Nitrate in crops
standard limit (*)
0
1000
2000
3000
lettuce control
lettuce WWTP
lettuce PP1
fennel control
fennel WWTP
fennel PP1
NO
3 in c
rops (
mg/k
g)
(*) EU Commission Regulation No 1258/2011 of 2 December 2011
26th Euro-Mediterranean Conference on Irrigation – Montpellier 12-15 October 2015