The moment I read Solar PV I knew these guys had lost the plot. Why on
earth do we need it to even have a pump, let alone moving parts and a costly Solar PV array to power it? If it's a big enough emergency, dump thousands of
"Life Straws" into the field and let the wonder of the human mouth suck the water through the straw directly from the river, which filters it by the time it hits the lips. Solar PV? Are they
trying to kill people by making this more expensive than it has to be? The Life Straw is also more flexible. People sometimes need to be on the move in emergencies. They can take their own Life Straw with them, and drink water from whatever river they find on the way.
There are also various bottle-filter versions that also use
no power. They don't need it, as the hand cranks the water through the cleaning membranes.
There is also the Watercone, which again is portable, and can desalinate seawater with solar heat (but no Solar PV needed!)
http://www.watercone.com/product.html But I guess when you work for MIT's space division and you have to reinvent something as basic as the wheel, one has to spend a million dollars to make a high tech space pen that will work in zero g rather than just use a pencil! The problem here, is we are talking about saving thousands of the world's
poor. They can't afford the 'space-pen' version. (Or, more accurately, they can't afford the emergency relief agencies to have cost limit supply). Instead, lets dump thousands of Life Straws and Watercones, and let *people power* and sunlight provide the energy to save their own lives.