Work In Progress (updated 02-18-13)
This page briefly discusses some of my water projects that are in development.
When I have proven these ideas, I will publish them on my main page and notify
interested parties. I include this page with the hope of receiving additional feedback
on the scope and direction of my water projects from the community. Projects
are arranged chronologically, so that my most recent developments appear at the
top of the page. Click here to see the hazardous water treatment model that I am
Compact Desalination Machine
In February (2013), I began formulating plans for a compact, human powered
desalination machine. Figures 1 and 2 show, in principle, how I plan to do this.
Basically, I want to combine the mechanical leverage of a double-ratchet fruit
press with a watertight silicone bladder, bagpipes (vents), steel vessel, and
seawater reverse osmotic filter to press freshwater from seawater, brackish
water and salty ground water. The press would squeeze the saltwater stored
in the bladder and force it through the filter. DOW Filmtec seawater reverse
osmotic filters are made to operate at 800 psi, However, DOW Filmtec
brackish water filters can operate as low as 100 psi - very doable. The
challenge will be with seawater. However, I believe we can gradually and
safely crank down on the bladder to start the flow of saltwater through the
filter. This would produce fresh drinking water on demand from saltwater.
This could be made compact and portable so that all people can have an ample
supply of drinking water in cases of emergency. Because it is human powered,
this desalinator would be available to the 1.5 billion people that are off the grid
too. The compact desalinator could produce at least 100 gallons of drinking
water per day.
In December (2010), I was inspired by the work of Excellent Development
using sand dams in Kenya to conserve and harvest rainwater. This prompted
me to think of similar ways to harvest stored rainwater - when sand dams
are not practical or applicable.
One suggestion is manmade 'sand ponds' - large, deep pits in the ground that
are lined with water-proof plastic and filled back with sand. Figure 3 shows a
drawing of what a typical sand pond may look like. The sand pond is like a
poor man's below ground cistern. Like a cistern, water does not evaporate
from the sand pond as it would in a normal pond. The sand traps water
between its particles and works as a natural filter making the below ground
water safe to drink.
The water-proof lining would be made from food-safe, polyethylene. I think
large tank liners and swimming pool liners could be adapted for sand ponds.
The ponds (cisterns) would be dug before the rainy season, lined with plastic,
filled with sand and vertical PVC (4" diameter) pipes. The vertical pipes will
serve as wells to collect water when needed and capped when not in use.
Buried with sand, plastic liners and PVC could last for hundreds of years.
Sand ponds would take advantage of natural and manmade topographic
gradients where rainwater flows and accumulates. These locations include
dry river beds, roadsides, borrow pits, hill bottoms and valleys near the
community. These locations may only be limited by the availability of
sand and suitable liners.
These sand ponds could be an affordable alternative for people living in
semi-arid places when sand dams are not an option. The sand ponds are
a scalable solution that could be built and sustained by local people using
supplied liners and tools. Finally, sand ponds may be easier and less
expensive to build than sand dams because no cement is needed.
SunFlower - Water Pasteurization Tool
The SunFlower is a large capacity solar cooker made from a large bowl
(~20 quarts) and a 3-ft square sheet of aluminum canvas. The bowl may be
made of any durable material including metal, plastic or wicker. Figure 4 shows
a SunFower heating water in a 5-gallon plastic vessel that is wrapped in a black
thermal blanket and covered with a large oven bag to conserve heat. In its
current configuration, the SunFlower is designed to work with any vessel up to
~5-gallons in volume. A 21-quart black enamel metal stockpot is ideal, but
vessels made from fired clay, glass or plastic will work too. The SunFower
can be assembled in about 2 minutes and is easy to maintain and store.
When handmade wicker bowls are used, the material costs are very low.
Field Testing - H2S Water Testing
Lead acetate test paper in 100-ml bottles will be used to field test water
sources for bacteria. Bacteria produce hydrogen sulfide (H2S) that turns
the water and test strips black within 24-30 hours. I will use a color chart to
estimate the bacteria count (ppm).
Figure 1. Compact Desalinator, Concept - Click to Enlarge.
Figure 2. Compact Desalinator, Model - Click to Enlarge.
Figure 3. Sand Pond (Drawing) - Click to Enlarge.
Figure 4. Large capacity solar water pasteurization using the 'SunFlower'
solar cooker. The SunFlower is designed to heat water vessels up to
five (5) gallons (~20 liters).