After spending some time on the internet looking at what has been done with respect to arsenic remediation in drinking water, I can safely say that a lot of time and money has been spent to solve a purvasive problem that afflicts a great many people with only some success. Countries afflicted by this problem include Bangladesh, India, Mexico, Chile, and Mongolia. Currently, Bangladesh and India have recieved the lion's share of attention due to the severity of the problem in those areas.
Remediation systems have ranged from simple iron/sand filtration units at the household level to larger RO systems for villages. The only phytoremediation system that I read about utilized brake fern to uptake arsenic through its root system. It appeared useful for removing arsenic from soil (which would reduce the amount of arsenic in groundwater due to leaching). I haven't run across any reports that water hyacinth is being used in a real world application to remove arsenic. Some of the pitfalls that have plagued current remediation systems revolve around a good understanding of the groundwater chemistry before bring the system on-line. High concentrations of ferrous iron and mangenese will clog up systems when aerated. It has been noted that high phosphate concentrations also shorten the lifespan of some systems. I think it would be very prudent to have a good understanding of the groundwater chemistry before we tried to install a real-world system. Hach methods (using a spectrophotometer) can provide results in the field at a reasonable cost for iron, mangenese, and phosphates. The Hach method for arsenic would not be very useful in the field due to the complexity of the analysis and the hazardous waste disposal of reagents.
I have emailed Dr. Haris, whose paper has prompted all this activity at CWB, to gather additional information about his research that was not presented in the paper. He has not responded yet, but I think his answers will be very helpful to constructing a viable remediation system. I would propose that we think small (we would need to define that in terms of gallons of water treated or people served) at first to work out the kinks before trying our hand at a larger
system. I would also propose that the system be operated via renewable energy sources. I have some thoughts on what a "first draft" system could look like, but I have to go now. I appreciate any feedback. Thanks