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Fog water

Fog water

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1. Introduction

Freshwater scarcity has increased over time and is expected to further intensify. This is due to

the uneven distribution of water resources and population densities, increasing demand for

water due to population growth, and changing climate and rainfall patterns. As the world’s

population and demand for fresh water increases, new water resources are needed. Different

options are available to improve water use efficiencies and productivity, but these may not be

sufficient to make the conventional water resources to meet the human needs in many water

scarce areas. Thus, water scarce countries, regions, and communities should increasingly

consider alternate, unconventional water resources in order to narrow the water demand-supply

gap. Among the various unconventional water resources, the potential to recover water from

air is by far the most under explored. One commonly overlooked aspect of the water cycle is

fog, which is an important part of the hydrology of coastal, high-altitude, and forested regions.

Fog water harvesting is being investigated as a sustainable alternative water resource for

drinking water and reforestation. Fog water harvesting involves using mesh nets to collect

water as fog passes through them. The materials of these nets, along with environmental factors

such as wind speed, influence the volume of water collected. In this article, a review of current

models for fog collection, designs, and applications of fog water harvesting is provided.

Aspects of fog water harvesting requiring further research and development are identified. In

regions with frequent fog events, fog water harvesting is a sustainable drinking water resource

for rural communities with low per capita water usage.

However, an analysis of fog water harvesting potential for the coastal areas of northern

California showed that fog yields are too small for use as domestic water in areas with higher

household water demands. Fog water shows particular promise for application in reforestation.

Fog water irrigation can increase growth rates and survivability of saplings in reforestation

efforts in regions with frequent fog events. Using fog collectors, denuded areas once dependent

on natural fog drip can be restored, benefit local hydrology and ecosystem recovery.

Improvement in fog collector designs, materials, and models to increase collection efficiency,

perhaps by inclusion of ideas from natural systems, will expand the regions where fog

harvesting can be applied.

Renewable energy could replace the conventional sources of energy such as fossil fuel and oil,

serving as an alternative source of energy. Non-renewable energy sources have been found to

reduce various environmental problems such as greenhouse gas emissions as they tend to

deplete at faster rates. Biological processes such as fermentation and anaerobic digestion for

the past decades have given rise to the production of biofuels such as biogas and bioethanol.

Biogas production is environment friendly and it is easy to produce.

Biogas is produced from biodegradable organic material under anaerobic conditions by micro-

organisms. The plants use materials such as bio-waste, sludge, manures, agro residues and

energy crops. Other materials are used to produces are described in detail in the next chapter.

A biogas plant is an anaerobic digester of organic material and it is treating waste for generating

biogas fuel. The treated waste can be uses as fertilizer while the biogas is the gas formed under

the anaerobic conditions. It contains mostly methane gas with inert gases including carbon

dioxide and nitrogen. Biogas plants can solve the environmental problems due to burning of

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animal dung as a fuel and can be used for the treatment of many forms of waste. Feedstock

which can be used for the biogas production includes plant material, non-meat or grease food-

wastes, and most types of animal dung.

Moreover, bioenergy and biogas are a renewable ,reliable and local source of energy. The

biogas industry comes as an alternative way for waste management with contribution to the

development of local economies. This emerging initiative provides an opportunity to deal and

manage the waste in a sustainable and economical manner hence ,highly influencing the

sanitation status of the society.

it is still necessary to put into consideration sanitation measures and or water treatment

strategies to ensure that the water produced every day is well conserved and chlorinated for

human consumptions and general use. Most of the fog water is safe due to factors such as most

of these sites are far off the access of human population. Most of these places have no and or

are sparsely populated thus minimal air and water pollutions [8]. Having said this, sanitation is

key in every aspect of survival and the rate of human wastes and or pollution in densely

populated areas are alarming hence measures should be put in place to ensure some of these

human wastes are actually converted into consumable energy and or biogas. This is to ensure

a productive ecosystem that reduces waste to the minimum.

Background

Fog harvesting purpose is to produce clean fresh water from vaporized water in fog. Over the

few past decades, the attention towards fog collection has increased. It is simple, sustainable

technology and low-cost system to produce clean water in dry regions around the world. Fog

collector systems work best in locations with repeated fog terms, such as places where fog is

driven by wind, usually coastal areas. However, this technology could also be used in

mountainous areas where water is presented in stratocumulus clouds, at altitudes of

approximately 2,000-6,500 ft. These fogs have the potential to provide an alternative source of

freshwater. Plant feed depends entirely on water droplets from fog or clouds, which is

considered as water vapor or water in gaseous form. After entering the system, the feed will be

condensed and produce a final product of a liquid drinking water.

As part of the natural global water cycle, at any given time, the amount of water in the

atmosphere is 12,900 km3, which represents 0.001% of total water and 0.04% of freshwater

existing in the planet (The Water Cycle, 2018). Under specific conditions, the air at ground

level may contain fog, which refers to the presence of suspended liquid water droplets with

diameters typically from 1 to 50 µm (Ritter A, 2015). Fog originates from the accumulation

and suspension of these tiny droplets of water in the air, creating masses of humid air over land

or sea. As an important source of water in desert environments, fog collection is achieved by

the collision of suspended droplets on a vertical mesh, where they coalesce, after which the

water runs down into a collecting drain and a tank or distribution system (Abdul-Wahab S.A,

2008).

Modern fog interception technology was first introduced in the mid-20th century, and there

have been major developments in fog collection systems in recent decades. Recent studies

focused on the material composition of fog collection nets and their sizes, direction, and

angle of installation of fog collectors, wind intensity, and climate and topography of the area.

A timeline on the history of several fog and dew water collection methods that were practiced

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geo 1. Introduction Freshwater scarcity has increased over time and is expected to further intensify. This is due to the uneven distribution of water resources and population densities, increasing demand for water due to population growth, and changing climate and rainfall patterns. As the world’s population and demand for fresh water increases, new water resources are needed. Different options are available to improve water use efficiencies and productivity, but these may not be sufficient to make the conventional water resources to meet the human needs in many water scarce areas. Thus, water scarce countries, regions, and communities should increasingly consider alternate, unconventional water resources in order to narrow the water demand-supply gap. Among the various unconventional water resources, the potential to recover water from air is by far the most under explored. One commonly overlooked aspect of the water cycle is fog, which is an important part of the hydrology of coastal, high-altitude, and forested regions. Fog water harvesting is being investigated as a sustainable alternative water resource for drinking water and reforestation. Fog water harvesting involves using mesh nets to collect water as fog passes through them. The materials of these nets, along with environmental factors such as wind speed, influence the volume of water collected. In this article, a review of current models for fog collection, designs, and applications of fog water harvesting is pr ...
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