Point of Use Coagulation and Flocculation

1. Point of Use Coagulation and Flocculation Turbidity Terminators: Morgan Rog Shubha Bhar Melanie Tan Lindsay Ellis

2. Comparing Chemical Coagulants

3. Alternative Coagulants: Plants Study done by Kenneth Yongabi, Tafawa Balewa University, Bauchi Nigeria Medicinal plants could have coagulative properties • Experiment: • Samples from each plant were dried, ground and stored • Alum was added to each sample • Coagulation mixtures added to turbid water samples • Alum was used as a control • The samples sat for 24 hours • Coagulative effect and bacterial counts were recorded • Extracts were tested for E. coli as a fecal contamination indicator

4. Jatropha Curcas • Common plant found in western and southern Africa • Roots and leaves highly medicinal • Seeds dried and ground up to determine coagulative properties • Results: • Coagulated 60-80% of particles • Decrease bacterial counts • Less effective than Moringa, but still more effective than Alum

5. Hibiscus subdariffa • Plant cultivated in Northern Nigeria • Contains red calyx extract dried and tested for coagulation • Results: • Effective coagulation • Effective disinfectant • Reduced E. coli and coliform bacterial counts better than Alum • Leaves water tinted red

6. Pleurotus tuberregium • Grown in Cameroon and parts of Nigeria • Mushrooms have medicinal value • Results: • Least effective coagulant • No antimicrobial properties • Still just as effective as Alum

7. Moringa oleifera • Originally from India, found in tropics in Asia, S. America, and Africa • Tough plant, easy to grow and cultivate • Drumstick, use dried seeds from pods • One tree cleans enough water for 5-6 people • Also contains pterygospermin, antibacterial • Results: • Coagulated 90% of particles • Much better than treatment with just alum • Antimicrobial properties • Bacterial counts reduced from “Too Numerous to count” to 2700 CFU

8. Preparation of Moringa Oleifera • Process: • dry and crush seeds • make into a paste • filter • add paste to turbid water • stir fast for ½ minute • stir slowly 5 minutes • settle 1 hour Dosage Demand: < 50 NTU 10-50 mg/L 50-150 NTU 30-100 mg/L >150 NTU 50-200 mg/L

9. Pros and Cons of Moringa Oleifera • Advantages: • Cheap, readily available • doesn’t alter pH, pH independent • doesn’t change taste • biodegradable sludge • Disadvantages • still needs to be disinfected • possibility of recontamination, no residual • needs to be fresh

10. POU Coagulation & Flocculation in Guatemala The Experiment, by Proctor and Gamble • Households assigned home flocculation-disinfection system • 4 controls using flocculation disinfectant and bleach • Stir water 30 seconds quickly, stir 5 minutes slow, let sit ½ hour, filter • diarrhea 2nd highest cause of death • water generally kept in open containers • use bleach to treat water

11. Effectiveness of Proctor and Gamble Experiment • How it Works: • Cheap flocculation disinfectant contained: ferricsulfate, bentonite, sodium carbonate, chitosan, polyacrylamide,potassium permanganate, and calcium hypochlorite • causes clumps to form and settle with stirring • chlorine residual 3.5 mg/L • Results: • Flocculation-disinfection (top) reduced diarrhea by 24% • Flocculation-disinfection with special container reduced diarrhea by 30%

12. Helpful Websites http://www.blackwell-synergy.com/links/doi/10.1111/j.1365-2672.2004.02309.x/pdf http://murungaexports.ebigchina.com/sdp/181012/4/cp-1011556.html http://www.treesforlife.org/project/moringa/uses/uses_water_lgscale_article.en.asp http://www.biotech.kth.se/iobb/news/kenneth04.doc http://www.ajtmh.org/cgi/content/abstract/69/4/411