1. IMPROVED AND INOVATIVE RURAL WATER SUPPLY DESIGN CONCEPTS DULEEPGO@GMAIL.COM

2. The purpose of water treatment is to provide a continuous supply of safe, palatable/potable drinking waterpotable RRPN Ratnayake  Free of unpleasant characteristics  Free of Disease-causing (biological) contaminants  Free of chemical contaminants Colour Turbidity Taste and odour  Free of plants like algae

3. All the above physical and chemical characteristics are mainly due to suspended matter or dissolved chemical constituents in the water RRPN Ratnayake In simple terms Water treatment is the removal of Unwanted suspended /dissolved matter (solids, liquids or gases) from water SLS 614USEPA drinking Water Regulationsdrinking

4. Type of Particle Particle Size (mm) Settling Time through 1 m of Water Gravel101 second Sand110 second Fine Sand0.12 minutes Clay & Silt0.012 hours Bacteria0.0018 days Colloid0.00012 years Colloid0.0000120 years Colloid0.000001200 years RRPN Ratnayake

5. TRAY AERATOR 4Fe 2+ + O 2 +10H 2 O 4Fe(OH) 3 +8H + When PH above 7.5 2Mn 2+ + O 2 +2H 2 O 2MnO 2 +4H + (Better if PH >9.0 for Mn oxidation) Trays filled with coke, crushed stone, lime stone or plastic media up to a depth of 300- 450mm.

6. RRPN Ratnayake

7. INDUSTRIAL POLLUTANTS

8. Slow sand filtration Plain sedimentation for >8 days Slow sand filtration Roughing filtration Aeration Turbidity, Algae,Colour, Taste, Odour, Iron, Manganese, Algal toxins, Fluoride Turbidity< average of 5 NTU, Algae (Chlorophil <.05µ)g/l,Colour, Taste, Odour, Iron<.3mg/l, Manganese<0.05mg/l, Algal toxins (to be tested) Slow sand filtration Turbidity< average of 20 NTU and maximum up to 50 NTU, Algae (Chlorophil <.05µ)g/l,Colour, Taste, Odour, Iron<.3mg/l, Manganese<0.05mg/l, Algal toxins Slow sand filtration Aeration Turbidity< average of 20 NTU and maximum up to 200 NTU, Algae (Chlorophil <.05µ)g/l,Colour, Taste, Odour, Iron<.2mg/l, Manganese<2mg/l, Algal toxins, fluoride<0.8mg/l Roughing filtration Turbidity< average of 60 NTU and maximum up to 500 NTU, Algae (Chlorophil <.05µ)g/l,Colour, Taste, Odour, Iron<.2mg/l, Manganese<2mg/l, Algal toxins, fluoride<0.8mg/l TREATMENT PROCESS SELECTION

9. Plain sedimentation for 8 days Slow sand filtration Roughing filtration Aeration/Ozonation Granular Activated carbon Turbidity< average of 60 NTU and maximum up to 500 NTU, Algae (Chlorophil <.05µ)g/l,Colour, Taste, Odour, Iron<.2mg/l, Manganese<2mg/l, Algal toxins(high), fluoride<0.8mg/l

10. To Storage Filter Bed No. 1 Influent Structure Filter Bed No. 2 Collection Pipes A Section A Water Collection Manifold SandPerforated Pipe SLOW SAND FILTER Scrape off the top 2-5cm sand layer for cleaning after clogging Timber planks should be used to move on sand bed

24. RRPN Ratnayake

27. Floating intake

28. One square kilo meter of 1 meter thick humus layer can store about 400,000 cubic meters of rainwater