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Irrigation Department (CEBAS-CSIC) MURCIA

EFFECTS OF TREATED EFFECTS OF TREATED WASTEWATER IRRIGATION ON WASTEWATER IRRIGATION ON

LEMON TREESLEMON TREES

Francisco Pedrero SalcedoFrancisco Pedrero Salcedo

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1. INTRODUCTION

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- At present, approximately 2% of all the wastewater is reused in the world, representing a volume of approximately 7.1 billion m³, or 0.18%of the world demand for water.

- In Spain, 2.500 Hm³/year are purified and 230 Hm³/year are wastewater reuse. Nowdays there are identified 100 direct wastewater reuse actions.

- In Murcia, 106 Hm³ of the treated wastewater in the 80 treatment plants, were reuse it. This number is the 17% of the renewable resources of the Segura basin.

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FteFte. . P.CatalinaP.Catalina, , E.OrtegaE.Ortega. CEDEX, 2002. CEDEX, 2002

SITUATION IN SPAINSITUATION IN SPAIN

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ASWater quality criteria Total dissolved solids (TDS)for agricultural reuse Salinity aspects

Microbiological aspects

The most important problem in Murcia´s treated wastewateris SALINITY.

There is a considerable interest in the long-term effects of reclaimedwastewater on crops intended for human consumption.

FteFte. ESAMUR, 2005. ESAMUR, 2005

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ASThe objetive was to compare two sources of

treated wastewater, one obtained with a secondary treatment and the other with a

tertiary treatment mixed with well water, in two different locations in Murcia, and to

study their effects on soil chemicalproperties and in the leaf mineral status.

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2. MATERIALS AND METHODS

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- Semi-arid climate.

Region of Murcia - Warm dry summers and mild rainy winters.

Cartagena and - Average annual precipitation between 200-300 mm

Campotejar - Average temperatures in Campotejar is 19,7 ºC andCartagena 18,7 ºC.

- The main daily ETo in Cartagena was 3,87 mm andin Campotejar 3,41 mm.

- The sites soil are silty-loam in Cartagena and clay-loam in Campotejar.

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CAMPOTEJAR

7 km North of Molina de Segura, province of Murcia.Coordinates (38º07´N, 1º13´W).

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•Orchard size: 10 ha.•Number of trees: 211.•Type and variety of crop or crops researched: “Fino” lemon tree grafted on “Macrophyla” rootstock.•Trees age: 7 years.•Plant spacing (meters): 8*6•Irrigation techniques: drip irrigation by four compensated pressure drips per tree, each with a flow rate of 4 L.h-1.

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CARTAGENA

The lemon tree orchard is located in San Felix, 4 km North of Cartagena, province of Murcia.

Coordinates (37º3´N, 0º58´W).

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•Orchard size: 12 ha•Number of trees: 3150 and 238 controlled•Type and variety of crop or crops researched: “Fino” lemon tree grafted on “Macrophyla” rootstock.•Trees age: 7 years•Plant spacing (meters) : 7*5•Irrigation techniques : drip irrigation by eight compensated pressure drips per tree, each with a flow rate of 4 L.h-1.

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CartagenaCartagena

CampotejarCampotejar

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Analysis during 2006

- Water analysis: monthly

- Leaf analysis: each three months, 24 trees by location in a randomized block design.

- Soil analysis: each six months in the humid bulb of the 48 trees.

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3. RESULTS AND DISCUSSION

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Water analysis

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Table 1: Physical-chemical and microbiological analysis of irrigation water used in both locations. The data contain average values derived from all the samples collected and analyzed during the 2006 year.

<400529354Sulphates

<150.303.10Phosfates

<505.913.86Nitrates

<100170221Chlorides

<10.500.56Fluorures

Optimum rangeCampotejarCartagenaAnions (mg l-1)

<1000.11Zn

<1000Pb

<500Cu

<100Cr

<0.0500Cd

<20.110.12Ni

Optimum rangeCampotejarCartagenaHeavy metals (mg l-1)

<1.500Mn

<10.841.39B

<900311334Na

<1.500Fe

Optimum rangeCampotejarCartagenaMicroelements (mg l-1)

<15065102S

<604170Mg

<20069107Ca

<1002542K

<50.272.06P

Optimum rangeCampotejarCartagenaMacroelements (mg l-1 )

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<100Helmints eggs (eggs/l)

100000E.Coli (UFC/100ml)

20004,3 x 102Faecal Coliforms (UFC/100ml)

Optimum rangeCampotejarCartagenaMicrobiological parámeters

<996SAR

>30 hard3456Hardness (ºF)

<352217SS (mg l-1)

<526Turbidity (NTU)

>345DO (mg l-1)

<1203039OQD (mg l-1)

<3044OBD (mg l-1)

450-20004871589TDS (mg l-1)

<1,52,122,82EC (dS m-1)

6,5-8,57,948,25pH

Optimum rangeCampotejarCartagenaParámeters

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- Both irrigation water are hard with a slightly high pH level..

- In Cartagena and Campotejar the EC is higher than 1,5 dS/m, and was primarily due to the high concentration of chlorides.

- Campotejar´s irrigation water has a high sulphatesconcentration.

- Cartagena´s irrigation water show higher values in chlorides, magnesium, boron, pH, total dissolved solids (TDS), turbidity and hardness.

- Cartagena´s reclaimed wastewater has a high levels of faecalcoliforms.

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Soil analysis

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ASTabla 2: Physical-chemical and microbiological analysis of soils in both locations. The data contain average values derived from all the samples collected and analyzed during the 2006 year.

Silty - claySilty - loamtexture

6069Zn

2987Pb

7295Cu

1124Cr

00Cd

916Ni

CampotejarCartagenaHeavy metals (µg g-1)

264342Mn

234260B

9001183Na

0,701,16Fe (%)

CampotejarCartagenaMicroelements (µg g-1)

533402S (µg g-1)

1,261,18Mg (%)

22,5211,42Ca (%)

0,571,03K (%)

426929P (µg g-1)

0.100.08N (%)

CampotejarCartagenaMacroelements

1,591,38Organic matter (%)

CampotejarCartagena

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AS 00Helmints eggs (eggs/l)

05E.Coli (UFC/100 ml)

07,3 x 103Total Coliforms

(UFC/100ml)

CampotejarCartagenaMicrobiological Parameters

0,1070,178EC (dS m-1)

7,937,84pH

CampotejarCartagenaParameters

887839Sulphates

899838Phosfates

346402Nitrates

13812063Chlorides

167244Fluorures

CampotejarCartagenaAnions (µg g-1)

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- The soil was clasified as silty-loam in Cartagena and silty-clay in Campotejar.

- The pH of the soil samples was found to be within the range of 6.6 to8.4.

- Both soils were clasified as normal soils with respect to salinity andsodicity hazards.

- Reclaimed wastewater use does not generate an important increase in soil organic matter and macronutrients level.

- High soil boron concentration founded in both locations.

- The higher microbiology load in Cartagena´s reclaimed wastewater, generates an increase in total coliform soil values in this location.

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Leaf analysis

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Tabla 3: Leaf analysis. The data contain average values derived from all the samples collected and analyzed during the 2006 year.

916864Sulphates

12431540Phosfates

205455Nitrates

870659Chlorides

323407Fluorures

CampotejarCartagenaAnions (µg g-1)

6053Zn

016Pb

1413Cu

5112Cr

322Cd

04Ni

CampotejarCartagenaHeavy metals (µg g-1)

3027Mn

2742B

106148Na

111195Fe

CampotejarCartagenaMicroelements (µg g-1)

0,240,28S (%)

0,250,31Mg (%)

4,524,52Ca (%)

0,851,56K (%)

0,100,12P (%)

2,752,71N (%)

41,7740,66C (%)

CampotejarCartagenaMacroelements

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- Foliar nitrogen levels are in the optimum range considered for citruscitrus trees development (2,5 – 2,8 %).

- Leaf boron content is between 100-130 µg g-1, wich is the limit forprimary toxicity simptoms.

- Leaf salt toxicity symptoms were not observed.

- The leaf macro-nutrients, micro-nutrients and heavy metalsconcentrations were always in the normal range.

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4. CONCLUSIONS

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• Microbiology quality indicators in Cartagena´s reclaimed wastewater exceed the recommended limits by the World Health Organization (WHO,1989) and the Environmental Protection Agency (EPA, 2004). The possibility of using reclaimed wastewater mixed with well water (Campotejar) is a good solution for improving the agronomic quality of TWW.

• The high salinity and boron concentrations are the main problems associated with TWW use in the Region of Murcia. Although leaf toxicity levels were not observed, salts accumulation can be a decisive parameter for the lemon crop.

• In both locations, a contribution of macronutrients and organic matter was not observed within a short time by the TWW application in the soils. An increase of pH was generated in both soils.

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