Wastewater Treatment and Reuse in Lebanon: Key policies and Future Scenarios

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Wastewater Treatment and Reuse in Lebanon Key
policies and Future Scenarios

• K. Karaa, F. Karam, N. Tarabey

3rd WASAMED Workshop on Non-Conventional Water
UseCairo, 6-11 December 2004
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WW Reuse Standards

• California Standards
• WHO Standards
• EU Standards
• FAO Standards
• National Standards
• Case of Lebanon Based on WHO Standards

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WW Reuse Standards

• Water quality guidelines for irrigation
• BOD5
• COD
• Suspended Solids
• Dissolved Solids
• Microorganisms
• Salinity
• Sodicity
• Toxicity
• Nutrients

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Standards for WW Reuse in Lebanon

• Standards for restricted irrigation (second class
  water)
• Can be achieved by crop restriction, appropriate
  irrigation methods, and appropriate on-farm
  management.
• BOD 25 mg/l, COD 90 mg/l, TDS 30 mg/l
• TSS 30 mg/l, B 1.0 mg/l, .
• FC 1000 count/100ml, Helminthes eggs lt1 per
  liter
• Standards for unrestricted irrigation Need
  higher level of treatment such as tertiary
  treatment.
• BOD 10 mg/l, COD 60 mg/l, TDS 10 mg/l
• TSS 10 mg/l, B 0.5 mg/l, .
• FC 2.2 count/100 ml, Helminthes eggs lt 1 per
  liter.

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Maximum contaminant level Maximum contaminant level Parameter a
Restricted Unrestricted Parameter a
25.0 90.0 30.0 2000 2700 10 6-9 1000 lt1 5.00 5.00 0.10 0.30 1.00 0.01 650 0.50 0.05 0.80 0.05 0.40 5.0 0.10 0.07 0.50 0.001 0.05 0.10 20.0 0.02 5.0 nil 0.002 10.0 10.0 60.0 10.0 1500 2000 10 6-8.4 2.2 lt 1 1.0 5.0 0.1 0.1 0.5 0.01 280 0.5 0.05 0.4 0.05 0.2 5.0 0.1 0.07 0.2 0.001 0.01 0.02 10.0 0.02 4.0 nil 0.002 5.0 Biochemical Oxygen Demand (BOD) Chemical Oxygen Demand (COD) Total Suspended Solids (TSS) Total Dissolved Solids (TDS) Electrical Conductivity (ECw) (micro S./cm) Sodium Absorption Ratio (SAR) pH Coliform (count/100 ml)b Helminthes eggs (per liter) Turbidity (NTU) Aluminum Arsenic Beryllium Boron Cadmium Chloride Chlorine, free residual after 60 min contact time Cobalt Copper Cyanide Fluoride Iron Lead Lithium Manganese Mercury Molybdenum Nickel Nitrate Selenium Zinc Oil Grease Phenol Ammonia
7 days average (a) In mg/l unless
otherwise specified (b) No value above 23/100
ml in any sample.
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Restricted irrigation (second class water)

• Selected crops
• Category A Protection is needed only for field
  workers
• Crops not for human consumption (cotton, sisal)
• Crops normally processed by heat or drying before
  human consumption (cereals, oilseeds like
  sunflower, sugar beet)
• Vegetables and fruits grown exclusively for
  canning or other processing that effectively
  destroys pathogens
• Fodder crops sun-died and harvested before
  consumption by animals
• Landscape irrigation in fenced area without
  public access (nurseries, forests and greenbelt).

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Case Study The BWWTP

• General Features
• Population
• Year 2004 92 000 inhabitants
• Year 2020 126 000 inhabitants
• Rural Communities
• Climatic variability in space and time
• Environmental degradation
• Rainfed agriculture
• Traditional agricultural practices
• Low farming revenues
• Rural exode

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Cropping pattern
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• Designed treatment capacity
• Year 2005 10 000 m3/day
• Year 2020 12 500 m3/day
• Potential irrigation volume for 7 month
  (April-October) 2.13 MCM
• Corresponding cultivated 355 hectares
  (irrigation duty 6000 m3/ha)
• Recommended irrigated crops winter wheat and
  cotton.

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Treatment Process

• Treatment process includes
• Preliminary
• Primary and secondary (sludge activated)
• Secondary sedimentation basins
• Chlorinating basins
• Solid treatment

BOD 25 mg/l TDS 30 mg/l
Second Class Irrigation Water
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Engineering Design

• 160 km of sewage networks
• 15 km of HDPE wastewater distribution lines
• 49 km of transmission pipelines with diameters
  varying between 80 mm and 350 mm
• reservoirs with capacities varying between 150
  and 600 m3
• 15 pumping stations
• Outfall from the treatment plant effluent
  discharges by gravity in a pipeline 800 mm in
  diameter, 1.2 km in length
• Main open channel to agricultural lands, long 7.4
  km
• Open ditches along the main open channel where
  treated effluent is pumped to the farms
• On-farm irrigation systems.

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Monitoring Program in the BWWTP
__________________________________________________
______________________ Parameters to be monitored
Frequency Standard ____________________________
__________________________________ BOD every
week 25 mg/l COD every week 125
mg/l PH every week 6- 9 Oil and
grease every week 10 mg/l TSS Every
day every week 50 mg/l Nematode eggs
every week lt 1 egg/liter Fecal
coliform every week 200
MPN/I00 ml Heavy metals every week 10
mg/l Phosphate every week 5
mg/l Ammonia every week 10
mg/l Nitrate every week 90
mg/l Fluoride every week 20
mg/l Sulfate every week 500 mg/l Sulfide
every week 1
mg/l Chlorine, total residual every week 0.2
mg/l Phenols every week 0.5
mg/l Arsenic every week 0.0
mg/l Cadmium every week 0.1
mg/l Chromium every week 0.1
mg/l Copper every week 0.5 mg/l Iron
every month 3.5 mg/l Lead every
month 0.1 mg/l Selenium every month 0.1
mg/l Silver every month 0.5
mg/l Zinc every month 2.0 mg/l Chlorine
every week 0.2 mg/l _____________________________
___________________________________________
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Irrigation Methods

• Conventional versus improved surface methods
• Surface irrigation includes furrow irrigation
• Modern Irrigation Techniques
• Sprinkler or spray irrigation methods
• Drip Irrigation systems

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• Difficulties and Constraints
• Small farms size and difficulties of
  establishing buffer area between farmers
• Intensive and diversified cropping pattern, lack
  of large mono-crop cultivated areas
• Difficulties related to farmers
• -         Variation among farmers for conviction
  with the use of TWW in irrigation
• -         No commitment to technical
  instructions properly, namely
• Irrigation date
• Water amounts applied
• Regular maintenance of the irrigation
  equipments (pumps, filters, pipes, etc)

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Recommendations Application of restricted
irrigation for the selected crops, with a severe
monitoring and control at farm level Shifting in
the near future to tertiary treatment to provide
WW quality suitable for unrestricted irrigation,
and to enable farmers to diversify their cropping
pattern.