Waste Stabilisation Ponds

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Waste Stabilisation Ponds

• Mara, D. (2003) Domestic Wastewater Treatment in
  Developing Countries, Cromwell Press, Trowbridge,
  UK

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Three principal types of WSP

• Anaerobic Ponds
• Facultative Ponds
• Maturation Ponds

BOD removal
Faecal bacterial removal
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Arrangement of WSP
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Function of Anaerobic Ponds
Depth 2-5m (typical 3m) 100g/m3.d Organic
Loading400g/m3.d
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Function of Facultative and Maturation Ponds
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Advantages of WSP

• Simplicity
• Low cost
• High efficiency
• Robustness

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(Perceived)Disadvantages of WSP

• Odour release
• Land
• Effluent quality The European Union requires
  25mg filtered BOD/l and 150mg SS (i.e. mainly
  algal SS)/l

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BOD Removal Kinetics
Completely mixed reactor used in the design of
WSP
Plug flow reactor used in the design of
constructed wetland
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Design of anaerobic ponds
Temperature (C) Volumetric loading (g/m3.d) BOD removal ()
lt10 100 40
10-20 20T-100 2T20
20-25 10T100 2T20
gt25 350 70
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Design of facultative ponds

• Design is based on the surface BOD loading
  (kg/ha.d)

Mara (1987)
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Design of maturation ponds
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Design of maturation ponds (continued)

• ?mgt ?f
• ?mlt ?mmin and
• ?S(m1)gt 0.75?S(f)

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Physical design of WSP
Va (L W) (L - 2sD) (W - 2sD) 4(L - sD) (W
- sD) D / 6
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Further study for self-improvement

• Constructed Wetlands
• Anaerobic Processes for Wastewater Treatment,
  e.g. UASB
• Aerated Lagoons
• Sequencing Batch Reactors (SBR)
• ???????, Text books, ????????????????, Journals
• www.sciencedirect.com, www.scopus.com, etc.