Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Ferrate - Solution to the Issue of Emergency Water Supply to the People in Flooding Areas, Tran Tien Khoi

239 views

Published on

This presentation is part of the ProSPER.Net Young Researchers' School 2017 ‘Water Security for Sustainable Development in a Changing Climate’.

Published in: Education
  • Be the first to comment

  • Be the first to like this

Ferrate - Solution to the Issue of Emergency Water Supply to the People in Flooding Areas, Tran Tien Khoi

  1. 1. FERRATE - SOLUTION TO THE ISSUE OF EMERGENCY WATER SUPPLY TO THE PEOPLE IN FLOODING AREAS Tran Tien Khoi Regional Center of Expertise on Education for Sustainable Development in Southern Vietnam International University Vietnam National University – Hochiminh City ttkhoi@hcmiu.edu.vn
  2. 2. CONTENT  Identifying problems  Current solutions  Gap - Objectives  Ferrate  Characteristics  Synthesis  Application  Method  Results and discussion  Perspective
  3. 3. MEKONG DELTA AREA Total area : 40,000 km2 Population: 17 million
  4. 4. MEKONG DELTA AREA Mekong river systems: • Main water supply source • Seasonal flooding (August to November)
  5. 5. IDENTIFYING PROBLEMS  Centralized water supply systems can serve only a minority of the population because of the scattering population of this region.  Water Treatment Plants: use surface water (rivers)  People have to use:  River water with simple treatment  Bottled water from private section (from river water)  Household harvested rainwater
  6. 6. IDENTIFYING PROBLEMS  River water is polluted with:  Increasing organic content,  Residual pesticides from agriculture activities  suspended solid (very high during flooding season)  domestic waste water  and bacteria (eg. E.coli, coliform)  More severe in flooding season
  7. 7. IDENTIFYING PROBLEMS – PESTICIDE POLLUTION  Pollution of drinking water sources with agrochemicals is often a major threat to human and ecosystem health in some river deltas, where agricultural production must meet the requirements of national food security or export aspirations.  Chau et.al. (2015) performed a survey on the use of different drinking water sources and their pollution with pesticides in rural areas of the Mekong River delta, Vietnam. 
  8. 8. IDENTIFYING PROBLEMS – PESTICIDE POLLUTION  The field work comprised both household surveys and monitoring of 15 frequently used pesticide active ingredients in different water sources used for drinking:  Surface water,  Groundwater,  Water at public pumping stations, water chemically treated at household level, harvested rainwater, and bottled water).
  9. 9.  The results show that despite the local differences in the amount and frequency of pesticides applied, pesticide pollution was ubiquitous.  Isoprothiolane: 8.49 μg/L (max. concentration)  Fenobucarb: 2.32 μg/L (max. concentration)  Fipronil : 0.41 μg/L (max. concentration)  They were detected in almost all analyzed water samples (98 % of all surface samples contained isoprothiolane, for instance). IDENTIFYING PROBLEMS – PESTICIDE POLLUTION
  10. 10.  Other pesticides quantified comprised butachlor, pretilachlor, propiconazole, hexaconazole, difenoconazole, cypermethrin, fenoxapro-p-ethyl, tebuconazole, trifloxystrobin, azoxystrobin, quinalphos, and thiamethoxam.  Among the studied water sources, concentrations were highest in canal waters.  Pesticide concentrations varied with cropping season but did not diminish through the year. IDENTIFYING PROBLEMS – PESTICIDE POLLUTION
  11. 11.  Even in harvested rainwater or purchased bottled water, up to 12 different pesticides were detected at concentrations exceeding the European Commission’s parametric guideline values for individual or total pesticides in drinking water (0.1 and 0.5 μg/L; respectively).  The highest total pesticide concentration quantified in bottled water samples was 1.38 μg/L. IDENTIFYING PROBLEMS – PESTICIDE POLLUTION
  12. 12.  Overall, they failed to identify a clean water source in the Mekong Delta with respect to pesticide pollution.  It is therefore urgent to understand further and address drinking water-related health risk issues in the region IDENTIFYING PROBLEMS – PESTICIDE POLLUTION
  13. 13. TRADITIONAL WATER TREATMENT TECHNOLOGY Coagulation (alum) Sedimentation Filtration (sand filter) Disinfection (chlorine, chloramine B, Aquatab) Preliminary treatment: • Remove particles (SS), colloids, color, turbidity • Partially remove organic content (30-50% TOC) • Kill bacteria, pathogens • Combine with residual TOC to produce DBPs (eg. THM) • Can not remove TOC, pesticides, herbicides, EDCs…
  14. 14. HOUSEHOLD WATER TREATMENT Coagulation (alum) Sedimentation Direct use Boiled before drinking Preliminary treatment: • Remove particles (SS), colloids, color, turbidity • Partially remove organic content (30-50% TOC) • Kill bacteria, pathogens • Can not remove TOC, pesticides, herbicides, EDCs…
  15. 15. HOUSEHOLD WATER TREATMENT
  16. 16. IDENTIFYING PROBLEMS Figure 1. There needs to be an effective solution to emergent water supply to them (using helicopter, high speed boat?)
  17. 17. IDENTIFYING PROBLEMS Figure 2. They need clean water (Is centralized system suitable for this case?)
  18. 18. IDENTIFYING PROBLEMS Figure 3. They need clean water (Is household treatment system suitable for this case?)
  19. 19. CURRENT EMERGENT SOLUTION Figure 4. Carrying the water to the site by highspeed boat: can you imagine their cost ? • Costly • Delayed • Almost impossible with strong water flowing • Cannot reach all household within a wide area • Small capacity
  20. 20. Figure 5. Carrying the water to the site by helicopter: can you imagine their cost ? CURRENT EMERGENT SOLUTION • Very costly • Cannot reach all household with a wide area • Cannot reach all household in wide area • Risk of houses blown up
  21. 21. Figure 6. VN Army mobile filtration unit CURRENT EMERGENT SOLUTION • Mobile • Effective only after flooding • Can be used on boat but less mobile
  22. 22. Figure 7. Carry the water to the site by simple transportation means: can you imagine their timing ? CURRENT EMERGENT SOLUTION • Need lots of labours • Very slow • Effective only after flooding
  23. 23. Figure 8. Chloramine B is the main chemical used for cleaning and water treatment after flooding in Vietnam POST-FLOODING SOLUTIONS
  24. 24. POST-FLOODING SOLUTIONS  Contaminated water is traditionally treated with alum and chlormine B (10g Cloramin B 25%/m3)  Simple, cheap, easy to use rồi mới cho chloramine B  Mainly remove turbidity and disinfect the water  Cannot remove pesticides, organic carbon and other organic pollutants.  Risk of forming toxic disinfection byproducts e.g THMs (trihalomethane)
  25. 25. CHLORINE TABLETS  Brand names you may recognize for this type of tablet are Aquatabs and Rothco’s Military “Chlor-Floc“.  NaDCC, also known as sodium dichloroisocyanurate or sodium troclosene, is a form of chlorine used for disinfection.  They are available with different chlorine content (e.g. 3.5 mg to 10 g) to treat from 1 to 3000 liters at a time. They are usually effervescent (meaning that escaping carbon dioxide gas causes the tablets to dissolve quickly, with a ‘fizz’), allowing the tablet to dissolve in less than 1 minute.  When added to water, NaDCC releases hydrochloric acid which reacts through oxidization with microorganisms and kills them.
  26. 26. IODINE TABLETS  Brand names you may recognize for this type of tablet are Potable Aqua, Coleman, and Coghlans.  Iodine Tablets use iodine to purify contaminated water.  Most iodine purification tablets tend to leave a funny taste to the water and some discoloration, however vitamin C or ascorbic acid can be added after the treatment time to improve the taste and remove the color.  This often comes in the form of two bottles with two separate tablets. Iodine water treatment has been proven to be somewhat effective against Giardia and not effective against Crytosporidium. (Source)
  27. 27.  Brand names you may recognize for this type of tablet are Katadyn, Potable Aqua, and Aquamira.  Even though the word “chlorine” is in the name, chlorine dioxide is neither iodine nor chlorine.  It uses a highly active form of oxygen to purify water so it leaves absolutely zero taste.  As a nice bonus the action of chlorine dioxide causes a lot of sediment to drop out of suspension (fall to the bottom) leaving the container of water more clear and further improving flavor.  While the general printed expiration date of chlorine dioxide is four years out, if it is kept in temperature controlled environment it can last indefinitely.  Chlorine dioxide tablets are a good choice for those allergic to iodine, with thyroid problems, or on lithium. (click here to learn more about chlorine dioxide) CHLORINE DIOXIDE TABLETS
  28. 28. OBJECTIVES We need to find out an solution of emergent water supply under harsh conditions which is:  Simple to use  Need no power source  Effectively remove suspended solid  Effectively remove organic pollutants, pesticides  Effectively remove bacteria and pathogen  Leave no strong odor, strange taste (And what else?)
  29. 29. RESEARCH QUESTIONS  Is ferrate applicable for emergent water supply in this area?  At what dose and condition?  In what form of production?
  30. 30. FERRATE  An Fe(VI) compound  A dual-function chemical reagent (oxidation and coagulation).  Reaction in aqueous systems with reducing matter: Acid FeO4 2- + 8H+ + 3e  Fe3+ + 4H2O E=2.20 V Neutral and weak basic FeO4 2- + 4H2O + 3e  Fe(OH)3 + 5OH- E=0.72 V
  31. 31. POTASSIUM FERRATE  A strong oxidant (Fe6+)  A coagulant : Fe3+ is hydrolysed to form insoluble Fe(OH)3, which will act as a coagulant.  A disinfectant due to strong oxidising nature  A promising multi-purpose water and waste water treatment chemical  Benefits from the combined effect :  Higher water quality  Lower operational and capital cost
  32. 32. FERRATE STABILITY IN AQUEOUS CONDITIONS Decomposition rate constant, k 7 8 9 10 11 12 0.0000 0.0005 0.0010 0.0015 0.0020 0.0025 0.0030 0.0035 0.0040 k(s -1 ) pH 0.25 mM ][ ][ 2 4 2 4    FeOk dt FeOd
  33. 33.  A large number of investigations on the oxidation of ferrate have been reported : strong, selective oxidant  Ammonia, cyanide, anilines, hydrogen sulphide  Alcohols, amino-acids, carboxylic, phenol  8 mg/L dose of ferrate could remove 99.9% total coliform and 97% total bacteria (Waite, 1979)  remove more turbidity from model colloidal systems Fe(III) and Fe(II) salts (Waite and Gray, 1984)  Enhance the removal of algae by alum coagulation; reduce alum dosage (Ma and Liu, 2002) APPLICATION OF FERRATE IN WATER AND WASTE WATER TREATMENT
  34. 34. FERRATE SYNTHESIS Basically, there are 3 methods for the synthesis of ferrate :  The dry oxidation method : iron oxide containing minerals are heated under strongly alkaline conditions with oxygen supplement The electro-chemical method : iron or alloy is oxidized. in the electrolyte solution of NaOH/ KOH  The wet oxidation method : an iron(III) salt is oxidised under strongly alkaline conditions using either hypochlorite or chlorine as an oxdising agent
  35. 35. LABSCALE FERRATE PREPARATION Wet oxidation method: oxidation ferric nitrate with hypochlorite Generating chlorine : KMnO4 + 8 HCl  MnCl2 + 5/2 Cl2 + 4H2O + KCl Bubbling the chlorine gas through a potassium hydroxide solution to form hypochlorite solution: Cl2 + 2KOH  KClO + KCl + H2O Oxidising ferric nitrate with hypochlorite : 2Fe3+ + 3OCl- + 10OH- 2FeO4 2- + 3Cl- + 5H2O  Ferrate purity : 90 – 95% (solid phase)
  36. 36. FERRATE PREPARATION RIG
  37. 37. FERRATE PRODUCT
  38. 38. EXPERIMENTAL METHODS AND MATERIALS • Surface water taken from Hau river – Mekong river branch •Buffer solutions: pH adjustment with HCl and NaOH Parameter Unit Value pH - 7.0 – 7.4 TSS mg/L 164 Turbidity NTU 109 Color Pt-Co 0.34 UV254 - abs cm-1 0.0436 CODMn mg/L 19.7 TOC mg/L 7.59 Fe mg/L 0.77 Coliforms MPN/100ml 29.104
  39. 39. RESULTS: TURBIDITY REMOVAL 0 10 20 30 40 50 60 70 80 90 100 0.25 0.5 0.75 2.5 5 7.5 10 Turbidityremoval(%) Ferrate dose (mgFe/L) pH 5 pH 6 pH 7 pH 8 pH 9 Low coagulation performance due to restabilization
  40. 40. RESULTS: ORGANIC REMOVAL 0 10 20 30 40 50 60 70 80 90 100 0.25 0.5 0.75 2.5 5 7.5 10 TOCremoval% Ferrate dosage as mgFe/L pH 5 pH 6 pH 7 pH 8 pH 9
  41. 41. RESULTS: EFFECTS OF PH 3.58 5.41 7.84 51.96 82.43 85.74 86.89 0 10 20 30 40 50 60 70 80 90 100 0.25 0.5 0.75 2.5 5 7.5 10 RemovalEfficiency(%) Ferrate dose as mgFe/L pH = 5 Turbidity 1.76 3.72 2.43 17.84 31.42 31.62 42.64 0 10 20 30 40 50 60 70 80 90 100 0.25 0.5 0.75 2.5 5 7.5 10 Removalefficiency(%) Ferrate dose as mgFe/LpH =7 • Oxidation effect : higher • Coagulation effect: lower • Oxidation effect : lower • Coagulation effect: higher TOC
  42. 42. RESULTS: DISINFECTION 0 20 40 60 80 100 120 0.25 0.5 0.75 2.5 5 7.5 10 Coliformsdeactivation(%) Ferrate dose as mgFe/L pH 5 pH 6 pH 7 pH 8 pH 9
  43. 43. CONCLUSION  Ferrate is a promising water treatment agent for emergent water supply to people in flooding region, due to:  Its simple use :all in one stage  Kill all coliform (bacteria) up to 4 log  Remove 80% turbidity and 42% TOC at pH 7  Coupled with a simple sand-filter, treated water meets VN standard for drinking water.  Effectively degrade pesticides, herbicides… (anticipated)
  44. 44. ACKNOWDGMENT This research is funded by Vietnam National University HoChiMinh City (VNU-HCM) under grant number C2015-20-32
  45. 45.  Thank you very much for your listening!

×