Technological Field Performance of a New Point-of-Use Water Treatment Technology in a Randomized Control Trial in Limpopo, South Africa

Transcription

1 Technological Field Performance of a New Point-of-Use Water Treatment Technology in a Randomized Control Trial in Limpopo, South Africa Courtney Hill UNC Water and Health Conference October 218 1

2 Background Treating water at the source gives risk for recontamination during transport or during storage Point-of-use (POU) water treatment technologies: Purify water in the household minimize recontamination 2

3 Ceramic Water Filter Filter mechanically removes pathogens Silver nanoparticles reduce live pathogens and provide residual disinfectant to reduce risk of recontamination Widely used and well developed Easily fractured, difficult transport, high initial cost 3

4 The MadiDrop Prototype initially developed at the University of Virginia Commercial product sold by Silivhere Technologies, Inc. Low capital cost, durable, easy to transport No turbidity removal Product Overview Small Porous Ceramic Tablet Embedded with Silver Utilizes Silver Ion Disinfection Designed to Treats 1 Liters of Water Daily Works for Six Months

5 Objective Prototype MadiDrops and filters effective in disinfecting water in the lab and in samples from early field studies (up to 4.2 log TCB reduction observed) Study aim: 1. Examine the technological performance of the commercial MadiDrop product in the field 2. Compare the performance of the MadiDrop commercial product to that of ceramic water filters and safe water storage containers in the field 5

6 Maditrial: Community Introduction Insufficient access to clean water was documented in the Dzimauli community Less than 2% of households reported treating their drinking water in Dzimauli in 29. Of these 1/4 used bleach or chlorine and 5% boiled their water, while the remainder let their water stand and settle 6

7 Maditrial: Village Stunting Prevalence (MAL-ED) Documented nutrition, pathogens, diarrhea, illnesses in Dzimauli every 2 days for 2 years 21% stunted at 6 months 35% stunted at 2 years Observed little diarrhea but high stunting/stool pathogen prevalence Likely due to environmental enteropathy from subclinical exposure to pathogens Villi get flattened, less ability for absorption of nutrients 7

8 Study Design Randomized Control Trial 4 Trial groups families enrolled 1.Filter in safe water storage container 2.MadiDrop in safe water storage container 3.Safe water storage container only 4.No intervention 8

9 Water Quality Sampling Water quality analyzed upon enrollment (June 216) and every six months Samples taken from untreated water in household and water from spigot of intervention Examined total coliform bacteria and E. coli prevalence in water via membrane filtration 9

10 Maditrial: Baseline Disinfection Source Filter: 3.17 log TCB reduction Madidrop: 3.47 log TCB reduction Safe water storage:.3 log increase TCB Total Coliform Bacteria per 1 ml of Water (cfu) Filter MadiDrop SWS Control Treated Total Coliform Bacteria per 1 ml of Water (cfu) Filter MadiDrop SWS Figure 1: box-and-whisker plots with the mean of the household water testing taken within four days of the intervention installation. 1

11 Maditrial: 6 month Disinfection 3 Filter: 1.56 log TCB reduction Madidrop: 2.5 log TCB reduction Safe water storage:.1 log increase TCB Total Coliform Bacteria per 1 ml of Water 3 1 Filter MadiDrop SWS Control Total Coliform Bacteria per 1 ml of Water Filter MadiDrop SWS Figure 2: box-and-whisker plots with the mean (diamond) of the household water testing taken within four days of the intervention installation. 11

12 Maditrial: 12 month Disinfection 3 Filter: 1.79 log TCB reduction Madidrop :2.47 log TCB reduction Safe water storage:.36 log decrease TCB Total Coliform Bacteria per 1 ml of Water Filter MadiDrop SWS Control Total Coliform Bacteria per 1 ml of Water 3 1 Filter MadiDrop SWS Figure 3: box-and-whisker plots with the mean (diamond) of the household water testing taken within four days of the intervention installation. None 12

13 Intervention Adjustments Filter and MadiDrop groups adjusted over first 12 months At baseline: MadiDrop group = 2 MadiDrops, filter group = filter + 2 MadiDrops Adjusted so that before six month sampling groups had a filter or a MadiDrop only SWS and control group remained the same throughout study After adjustments, comprehensive sampling showed 3% silver levels above 1 ug/l (average 37 ug/l concentration) in both groups In accordance with UVA IRB, both groups replaced with ceramic water filters without silver Study aim: 1. Examine the technological performance of the commercial MadiDrop product in the field. 2. Compare the performance of the MadiDrop commercial product to that of ceramic water filters and safe water storage containers in the field 3. Assess the importance of silver in ceramic water filters 13

14 Maditrial: 18 month Disinfection Filter without silver: 1.18 log TCB reduction Safe water storage:.3 log increase TCB Total Coliform Bacteria per 1 ml of Water Total Coliform Bacteria per 1 ml of Water No Silver Filter SWS Control No silver filter SWS Figure 4: box-and-whisker plots with the mean (diamond) of the household water testing taken within four days of the intervention installation. 14

15 Maditrial: 24 month Disinfection 3 Filter without silver:.12 log TCB reduction Safe water storage:.64 log increase TCB Total Coliform Bacteria per 1 ml of Water 1 3 No Silver Filter SWS Control Total Coliform Bacteria per 1 ml of Water 1 No Silver Filter SWS Figure 5: box-and-whisker plots with the mean (diamond) of the household water testing taken within four days of the intervention installation. 15

16 Maditrial: Conclusions Both MadiDrop and silver impregnated filters significantly reduced TCB Mechanical filtration alone is not sufficient for water treatment The use of a safe water storage container alone has little to no effect on quality of drinking water 16

17 Acknowledgements University of Virgina Jim Smith Becca Dillingham Liz Rogawski David Kahler University of Venda Pascal Bessong Emmanuel Nyathi Joshua Edokpai 17

18 Questions? 18