Fog collection refers to the collection of water from fog using large pieces of vertical canvas to make the fog-droplets flow down towards a trough below the canvas, known as a fog fence.
Through a process known as condensation, atmospheric water vapor from the air naturally condenses on cold surfaces into droplets of liquid water known as dew. The phenomenon is most observable on thin, flat, exposed objects including plant leaves and blades of grass. As the exposed surface cools by radiating its heat to the sky, atmospheric moisture condenses at a rate greater than that of which it can evaporate, resulting in the formation of water droplets.
Fog harvesting provides a cheap complementary water source for arid and semiarid, rural regions. As the wind blows the fog through specially designed nets (fog collectors), tiny droplets of condensed water form on the mesh. They are collected in a gutter and transported to a storage site. The collected water can be used for domestic purposes or agricultural purposes.
The key objective of this idea is to provide affordable, reliable and easy to install source of water to the communities that face shortage of water in Tanzania and Africa at large. This will help to minimize problems related to water shortage such as drought and diseases
Vision: Is to commercialize and spread the technology making it available from family level, community level, institutional level and national level.
Water is simply harvested by using a fog collector raised high from the ground. A fog collector is simply a frame that supports a section of mesh in a vertical plane. The large, operational fog collectors are typically made of two supporting posts, and cables on which the mesh is suspended. In addition, there is a network of guy wires to support the posts, a plastic trough to collect the water, and pipes to move water from the troughs to a reservoir or cistern. The large collectors are usually 12 m long and 6 m high. The mesh covers the upper 4 m of the collector. This gives a collecting surface of 48 m2 and typical water production rates of 150 to 750 liters per day depending on the site. Alternatively, the collectors may be more complex structures, made up of a series of such collection panels joined together. The number and size of the modules chosen will depend on local topography and the quality of the materials used in the panels. Multiple-unit systems have the advantage of a lower cost per unit of water produced, and the number of panels in use can be changed as climatic conditions and demand for water vary.
The surface of fog collectors is usually made of fine-mesh nylon or polypropylene netting. Studies of various mesh densities in El Tofo (Chile) showed high efficiency at 35% coverage, mounted in double layers (UNEP 1997). This proportion of polypropylene-surface-to-opening extracts about 30% of the water from the fog passing through the nets (UNEP 1997). As water collects on the net, the droplets join to form larger drops that fall under the influence of gravity into a trough or gutter at the bottom of the panel, from which it is conveyed to a storage tank or cistern.
Costs are variable depending on location, access and whether all labour costs are donated. The experience of FogQuest (www.fogquest.org) shows that small fog collectors for an evaluation cost 100 usd to 200 usd each to build. The large 40 m2 fog collectors cost about 1500 usd
The products are planned to be priced at (cost price plus 25% mark-up).
Fog water chemistry has been studied and found to meet the WHO drinking water standards. Because it is produced in remote areas few sources of potential contamination are present. Normally bacterial contamination would also not be an issue since it is very unlikely that there would be harmful bacteria in the fog. The mesh itself rapidly cleans itself from any dust that may have settled on it during a dry period. Once the water is produced by the fog collector the same precautions and considerations apply as for any other water source (From FogQUEST n,y)
- Low capital investment and other costs compared to other ways of water supply such as well drilling
- It doesn’t depend on the rain
- Easy to install, operate and maintain
Yield varies from day to day as well as seasonal depending on the location
This project requires the following personnel
- Managing director
- Technical Officer
- Sales and marketing office
- 3 skilled laborers
I plan to use the following methods to market and promote the products
- Local radios marketing
- Public speaking
- Tradeshows marketing
- Community events sponsorship
- Target market
This projects targets the following
- People living in arid and semi-arid areas
- Communities with no access to water
- Institutions like schools, hospitals
- Farmers (For irrigation)
For this project to come to its operations will require the following