GREENHOUSE BASED DESALINATION FOR
SUSTAINABLE AGRICULTURE IN DESERT CLIMATE
MOHAMED NOUR1, ASHRAF GHANEM1, MARTIN
BUCHHOLZ2, AND AHMED NASSAR1
1
Cairo University, Faculty of Engineering
2 Technical University of Berlin
OUTLINE
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Background and motivation
Methodology
Greenhouse construction and operation
Results and discussions
Conclusions and final remarks
BACKGROUND
• Water scarcity in Arab world
• Fading of fresh groundwater resources
(fossil)
• Over mining of ground water increasing
salinity
• Sea water intrusion in coastal zones (Nile
delta)
• Climate change – sea level rise – sea water
intrusion – increasing groundwater salinity
BACKGROUND
• Direct irrigation with brackish water poses
limitations on the kind of crops to be cultivated
and reduces crop yield
• All this water quantity/quality problems results in
significant shortages in food supply and food
security issues
• This provokes a fundamental change of water
management including a more efficient use of
limited freshwater resources and the use of
unconventional water resources like sea- and
brackish water
MOTIVATION
Brackish groundwater resources of salinities in the range of 2000 to
10,000 ppm are widely available in the western desert areas and Sinai.
OPPORTUNITIES
TDS ~ 0
Mix and use for
irrigation
Brackish
• Horticultural production in closed environments: more
and better food by the practice of CO2 accumulation ,
pesticide free plant
• The concept, known in the literature as the Watergy
(Buchholz et al., 2005; Buchholz, 2000)
CHALLENGES
• Temperature and Humidity control in a
closed greenhouse
• Promoting evaporative cooling
• Water harvesting
• Co2 assimilation for boosting crop yield
• Cost reduction – local material and waste
recycle
OBJECTIVES
• Advancing Watergy by:
– using brackish water in the greenhouse
irrigation system
– utilizing very high salinity desiccant in the
greenhouse heating/cooling system
– developing of cooling methods for closed
greenhouses, that will allow the use under
climatic conditions of Egypt and the Middle
East
– enhancing the economic feasibility of the
system by researching the use of local
materials
METHODOLOGY
100 m2 closed greenhouse
INITIAL RESULTS
• Focus on desalination capacity of the
proposed greenhouse. Other aspects
including greenhouse cooling, horticulture
diversity and material selection are
described elsewhere.
• Initial results: condensed water within the
greenhouse amounts to 2.5-3.8 L/m2/d.
• Design allows harvesting nearly 80% of this
condensed water. Thus, collected fresh
water amounted to 2-3 L/m2/d.
STUDIED SCENARIOS
• Scenario 1: Cultivating cherry tomatoes in
a 20 greenhouse setup
• Scenario 2: Cultivating cucumbers in a 20
greenhouse setup
• Scenario 3: Cultivating bell peppers in a 20
greenhouse setup
Cropping Pattern (20 ha)
Cherry tomatoes
Bell peppers
Cucumbers
Water consumption per
cropping season (m3)
180,000
168,000
90,000
Condensed water recovery
per cropping season (m3)
72,000
84,000
36,000
*Target irrigation water
salinity for optimum yield
(mg/L)
<1000
<960
<1600
Maximum salinity for
brackish water supply –
Proposed greenhouse
system (mg/L)
1700
2000
2700
Productivity – Proposed
greenhouse system (% of
maximum yield)
100%
100%
100%
*Productivity – other
typical greenhouses (% of
maximum yield)
90%
77%
77%
10%
40%
23%
50%
23%
40%
% Increase in productivity
% Water saving
Source water TDS = 3000 mg/L
Cropping Pattern (20 ha)
Cherry tomatoes
Bell peppers
Cucumbers
Water consumption per
cropping season (m3)
180,000
168,000
90,000
Condensed water recovery
per cropping season (m3)
72,000
84,000
36,000
*Target irrigation water
salinity for optimum yield
(mg/L)
<1000
<960
<1600
Irrigation water salinity
(mg/L)
3000
3000
3000
Proposed greenhouse
modified salinity (mg/L)
1800
1500
1800
*Productivity – Proposed
greenhouse system (% of
maximum yield)
92%
88%
96%
*Productivity – other
typical greenhouses (% of
maximum yield)
72%
55%
71%
20%
40%
33%
50%
25%
40%
% Increase in productivity
% Water saving
CONCLUSIONS AND FINAL REMARKS
• Joint effort between CU and TU-Berlin to develop
technologies for sustainable pesticide free
agriculture using brackish water in an integrated
desalination horticulture solar greenhouse.
• Watergy can save in irrigation water 40% for
tomatoes and cucumbers and 50% for bell
peppers.
• Maximum crop yield can be achieved at extended
upper salinity levels: from 1000 to 1700 mg/L for
cherry tomatoes; from 960 to 2000 mg/L for Bell
Peppers; and from 1600 to 2700 mg/L for
cucumbers.
CONCLUSIONS AND FINAL REMARKS
• Under a possible scenario of increasing
groundwater salinity to 3000 mg/L from
excessive mining and possible sea level rise, the
proposed greenhouse can serve in increasing
crop yield by: 20%, 33%, and 25% for cherry
tomatoes, Bell Peppers, and Cucumbers,
respectively. Coupled with irrigation water saving
of 40% for tomatoes and cucumbers and 50% for
bell peppers.
• The proposed technology not only provides water
saving and increase in crop yield under brackish
water conditions but also provide organic
pesticide free produce.
ACKNOWLEDGMENT
• ICDEMOS 2014
Thank You!!!!!!!!!!!!!!!
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