Purifier Performance

What cleans water best?
Biological
1) Bacteria...............................................Chlorine
2) Viruses................................................Chlorine
3) Parasites
Single Cell:
I Ameba...........................................Heavy chlorine & sediment filtration
II Giardia...........................................Heavy chlorine & sediment filtration
III Cryptosprodium...............................Heavy chlorine & sediment filtration
Multi-cell:
I Worms...........................................Heavy chlorine & sediment filtration
Chemical
1) Naturally Occurring Chemicals
I Arsenic..........................................Activated carbon, pH adjustment
II Uranium.........................................Activated carbon, pH adjustment
III Nitrates (Waste induced)
2) Human-made/ used Chemicals
I Heavy Metals...................................Activated carbon, pH adjustment
II Volatile Organics
Benzene (Fuel breakdown)...............Activated carbon, pH adjustment
Dioxin (Bleaching agents)................Activated carbon, pH adjustment
III Disinfectant By-products
Tri-halomethanes............................Activated carbon, pH adjustment

Performance (when used correctly)

Parameter: ..........................Expected Performance:

- Biological:
- Total Coliform:.......................0 per 100 ml
- Fecal Coliform.......................0 per 100ml
- HPC Agar Plate Growth..........<30 colonies per 1ml, (TFTC) bottom bucket
(TFTC = “Too few to count”)
- Parasitic Cysts......................98% Mechanical Removal to 5 um

- Nitrates:...................................<44 mg/liter

- Water Quality:
- pH.........................................>7.5 and <9.5
- Turbidity.................................< 10 NTU
- Free and Residual Chlorine.......>.2 mg/l and <1mg/l

- VOC Removal..............................To USEPA MCL
Tested via “spikes” of three classes or organic chemicals.

- Total Trihalomethanes:.................<100ug/liter

- Longevity:
- Top Bucket Filter:....................Until Plugged (~2 years except for river water)
- Bottom Bucket Filter:...............Material change every 6-9 months

- Disinfectant levels:
- Top Bucket:..............................67 mg Aquatab per 5 gallons (3.35 mg/l, initial)
- Bottom Bucket:........................17 mg Aquatab per 5 gallons (.875 mg/l)

- Arsenic Removal:........................NOT TESTED, NOT RECOMMENDED
There is no technical reason to believe that the purifier can reduce heavy concentrations of arsenic to the USEPA MCL.

- Salt Removal:............................NONE

- Heavy Metal Precipitation:...........NOT TESTED
Testing on similar filters shows that heavy metal removal is likely, provided the pH remains above 7.
Environmental Engineering School of Massachusetts Institute of Technology

A number of graduate theses projects have been associated with the Gift of Water. These are copyrighted publications and available via consent of the author and university.

MIT Theses of interest include:

* Trihalomethane Formation in Rural Household Water Filtration Systems in Haiti
by Daniele S. Lantagne

* Filtration of Giardia cysts from Haitian Drinking Water
by Michael Joseph Borucke

* Household-Level Point-or-Use Water Filtration in Haiti: Strategies for Program Management and Sustainability by Farzana S. Mohamed

* Sodium Hypochlorite generation for household water disinfection in Haiti
by Nadine van Zyl