Instructions
In many areas around the world, there is a shortage of clean drinking water. In poorer communities, the drinking water has a high chemical and bacterial content. Many of these small communities have a lack of technology with poor access to electricity. Therefore, solar distillation stills are a great solution to purifying water sources in order to provide clean drinking water to these communities.
Problem Statement
The purpose of this project is to develop new versions of solar distillation stills and document their performances based on the efficiency of purifying brackish groundwater without the addition of electricity. Through the use of solar distillation, we can use heat from the sun to evaporate potable water from the brackish water. The goal of this project is to design a still with the highest possible water production per unit cost of the process equipment.
Background
Solar water stills have been used for thousands of years. The original use was to get salt from salt water, over time, it was used to purify contaminated water and make it potable. The first documented solar stills were in the sixteenth century. The first large-scale solar still was built by a mining community in Chile in 1872. Solar stills became popular in the US Navy in World War II by making inflatable plastic stills for drinking water. Developing countries are interested in solar distillation treatment process because of their need for clean water. The water being analyzed in this competition is brackish water with a variety of dissolved chemicals and minerals. The objective for the final design is to reduce the amount of contaminants in the water with the most efficient and cost effective design. The brackish water contains a multitude of contaminants, which are outlined in the following table:
Table–Brackish Water Condition
Component |
Value |
Conductivity |
6100 µS/cm |
Sulfate |
3300 mg/L |
Chloride |
550 mg/L |
Hardness(as CaCO3) |
3000 mg/L |
Sodium |
700 mg/L |
Calcium |
600 mg/L |
Magnesium |
375 mg/L |
Silica |
25 mg/L |
Strontium |
10 mg/L |
The still is going to be designed to scale, and will be implemented in Flagstaff, AZ. Flagstaff’s soil conditions will be a factor in the overall design. The materials being used will depend upon what is available in the City of Flagstaff. Overall, the unit producing the largest amount of distilled water for the lowest price possible will be the final design.