Dr. Francisco Pedrero Salcedo

Department of Agricultural and Environmental Science

University of Bari “Aldo Moro“

Irrigation DepartmentCEBAS-CSIC

Wastewater reuse for irrigation – summary of current

and future research activities

Workshop

RECLAIMED WATER USE IN MEDITERRANEAN AGRICULTURE

Reclaimedwater use in agriculture

Pilot plants at PLOT LEVEL

Pilot plants at DISTRICT

LEVEL

New technologies

Disseminationand publicperception

Miscellaneousproblems

Irrigation Department water reuse projects

-A network of experimental plots in different locations and different

types of reclaimed water and crops.

-The effect of using reclaimed water on tree physiology, performance,

quality and safety of crops

- Effects on the long and medium term effect on soil salt accumulation,

unsaturated area and groundwater pollution.

Pilot plants at plot level

Use of reclaimed water and Regulated Deficit Irrigation (RDI) on mandarin and grapefruit

2008-2010Evaluate the agricultural impact of using

reclaimed water for irrigation of citrus trees under

optimum and deficit irrigation conditions and to

assess the use of GIS tools for planning and

management of water reuse projects.

A tendency to reduce the number of fruits on was detected under RW treatments.This reduction was more pronounced under regulated deficit irrigation (RW-RDItreatment).

Combined effects of RDI strategies and reclaimed water increased some fruitquality parameters on mandarin trees. [Vit.C] RDI-RW > RDI > Control treatments.

[Na], [B] and [Cl] exceeded the phyto-toxic levels in reclaimed irrigation-water.Although no toxic problems have been detected during the experiment, some mildtoxicity symptoms started appearing during the last year and therefore long termeffects could be more pronounced.

Irrigation with reclaimed water tends to accumulate salts within the plant rootzone. Therefore, careful monitoring is needed to avoid possible reduction in the soilagronomic properties.

Conclusions

Long term effects

Ayers and Westcot (1985) for citrus (ECe= 1.7 dS m−1)

Yield on mandarins

• After evaluating the validity of three indicators (gas exchange parameters,stem water potential and leaf chlorophyll content) our results showed theneed of seasonal measurements of leaf chlorophyll content as an importantdiagnostic indicator of salt stress on field crops of grapefruit.

• Phytotoxicity thresholds for Na, Cl and B that cause a decrease in citrusyields were established.

• Additionally, we observed salt accumulation at leaf level that could eventually lead to possible risks in crop sustainability in the medium to long term.

Conclusions

CtrJ OJ F M A M J A NS D

RDI

100 % ETc

50 % ETc

Dual-WaterJ OJ F M A M J A NS D

Regulated SalineIrrigation “RSI”

100 % ETc

ECw > 4ECw ≈ 1 ECw ≈ 1

ECw > 4 ECw > 4ECw ≈ 1

NEW treatments

Best Managements Strategies

ON THE OTHER HAND…

2007 2015

Water and Agriculture Research Platform CEBAS-CSIC

Grenhouses 860m2

a

f

e

b

c

d

Soil surface

• Research projects

- Agricultural reclaimed water use effects on horticultural crops

growing on soil and hidroponics.

- Water treatment prototypes testing

- Food safety risk and security studies.

- Emerging contaminants

- Sludge

• Enterprise collaborations

- Precision irrigation with soil and environmental sensor integration

• Visits, trainning days, international courses ,

dissemination, MsC, phD.

TOMATO

ZUCHINNI 3 LETTUCE, PARSLEY, CABAGGE,

BROCCOLI AND COURGETTE

PEPPER

IRIS complementary studies

Safety assessment of greenhouse hydroponic tomatoes and peppers irrigated with reclaimed and surface water

IRIS complementary studies

Fecal indicator microorganisms such as E. coli were found in relatively low levels in surfaceand reclaimed water. However, presumptive positive Salmonella spp. samples (prevalence7.7%) were found in both water sources.

• Fertilizer solutions (FS) were used:

FS1 MKP 0-52-34, 75 g/L KH2PO4, FS2 KNO3, FS3 Ca(NO3)2, FS4 micronutrients solution, Fe FS5 HNO3

• Three E. coli strains (CECT 471, 515, and 516)

Conclusions

• Although the biggest problem in Murcia reclaimed water is salinity and boron concentration, in this

experience, reclaimed water doesn´t represent a danger for short-term agricultural use

• The use of reclaimed water for irrigation was a significant saving of mineral fertilizers (N - P2O5 - K2O -

CaO) for both substrates

• Among the fruit quality parameters , there were no differences between the different types of water (IC

and TT ) although there was some difference between substrates (CF and RW ) .

• After the analysis performed in plant and fruit , it can be concluded that the use of reclaimed water for

hydroponic tomato and pepper crop irrigation, is suitable under conventional agricultural practices (

hydroponics , drip irrigation , polyethylene greenhouse, etc ....) and offers a microbiological food safety .

- Associated with irrigation districts, often organized around

irrigators associations with concessions for use reclaimed

water.

- Continuously assess the quality of irrigation water used.

- Assessing the effects of reclaimed water on plant and

soil, but also estimating how the reservoirs, water pipes

systems and all the associated infrastructures with the

distribution could affect.

Pilot plants at district level

Feasibility study of using reclaimed water from the WWTP of Jumilla in the Miraflores Irrigators Community

MirafloresIrrigators

Community

Conceptual

planning

Facility

planning

Feasibility

study

GIS

Potential use of reclaimed water with GIS-based multicriteria analysis

New Technologies

Constraints Transport < 8 KmR to streams > 100 mR to wells > 100 mR to reservoirs > 500 m

Constraints R to population agglomerates > 200 m

Constraints0 < Slope < 12%.

Constraints 10% < Clay

1m < Depth

New Technologies

Parameters Area (ha)

Studied area 13,944

Area without population agglomerates 12,445

Economic restriction area 7,805

Area with slopes < 12% 10,852

Area occupied by antrosol soils 8 ,862

Area without water sources 5,345

Potential reuse area 1,607

New Technologies

New Technologies

132 m

59 m

82 m

45 m

105 m

48 m

106 m

30 m

135 m

43 m

Aquifer depth

Optimal groundwater recharge

5Km

Wastewater treatment plant

1

3

5

4

2

After analyzing all the criteria established, of the total area studied (237,960 ha),

only 2.7% (6,442 ha) is considered optimal for aquifer recharge

Nutrients

High temperatures

Light

Macro and micro algae growth and

development on the store ponds.

Filters and drippers

irrigation obturated

Miscellaneous problems

Location:

Reservoirs:

Miscellaneous problems

AC1

• 58.900 mᶾ• Reclaimed water• Ultrasound 300 W

AC2

• 5.200 mᶾ• Reclaimed water• Ultrasound 150 W

SJ

• 33.600 mᶾ• Reclaimed water• Without ultrasound

-Conferences at all levels, both users and generators of such

waters, to raise awareness of the importance of it.

-Economic analysis. Within this economic assessment all

environmental benefits– including non-market benefits – should

be included. To estimate the non-market benefits that society

attaches to the use of reclaimed water for agricultural purposes

Dissemination and public perception

• Safety and toxicity risks

• Economic concerns (energy-water)

• Social acceptance

Future studies on water reuse based on the main

barriers

New microbiological indicators

Plant uptake models for emerging contaminants

RISK EVALUATION

Determining acceptable pollutants

concentrations for human health

Thanks for your attention