Five Water Purification Designs

According to the World Health Organization (WHO), 748 million people lack access to uncontaminated drinking water sources. Moreover, WHO estimates that 1.8 billion people use a fecally contaminated drinking water source, 2.5 billion lack access to improved sanitation facilities and more than 840,000 people die from water related diseases annually. Contaminated water is the number one cause of death in developing countries, causing diseases such as cholera, hepatitis, typhoid fever, malaria, ascariasis, dengue fever and many other deadly illnesses. In fact, contaminated water is the number one public health concern globally based on its impact to society, according to the WHO. Fortunately, the WHO estimates that 10% of the global disease burden could be prevented with improved water supply and sanitation. In light of this, a number of innovations and technologies are providing growing solutions to this problem.

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Related program: B.S. in Environmental Management

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Ultra Violet Filtration

Ultraviolet water filtration systems such as the Camelbak 25 Ounce All Clear Bottle and the UV Waterworks systems use ultraviolet (UV) rays to destroy harmful pathogens in drinking water. UV light filtration is highly effective, eliminating up to 99.9% of harmful microorganisms in water. The Camelbak Bottle has several advantages including quick filtration, (it takes just one minute to produce clean water), easy portability, and simplicity of use. Further, the UV bulb inside the Camelbak lasts for 10,000 cycles and produces enough energy to clean three liters of water for seven years. Some of the disadvantages of the Camelbak bottle include its high cost; at $99, it may be beyond the reach of many users, especially in developing countries. Further, the Camelbak only purifies drinking water and is not suitable for cleaning other water such as water for cooking. It also has limited sanitation applications. The UV waterworks has the advantage of being able to purify up to four gallons of water in a minute, which is enough drinking water for almost 2000 people. Its main disadvantage lies in the fact that that it requires electricity or another power source such as a car battery or solar cell to function.

Solar Purification

Solar water purifiers typically use sunlight to disinfect contaminated water and make it safe for drinking. Purification systems such as the SODIS (Solar Disinfection) uses clear water bottles filled with drinking water and set out in sunlight for up to six hours. The UV lights from sunlight destroy germs such as viruses and bacteria as well as parasites such as giardia and cryptosporidia. The SODIS has several advantages: It is cheap and easy especially since it uses PET bottles, which cost little and can be recycled easily. Disadvantages include: limited volume of water purified, a large number of bottles required in order to purify sufficient quantities of water, and long purification time.

Another system is (Solar Power) from MIT. The system is consists of photovoltaic panels, a large tank to store water, and a small shed to store the pumps, filter water, and auto-compute tasks.

The main advantage of this system is the fact that a large volume of water can be produced at a cheap cost. The disadvantages arise from the fact that the solar system must be built and community members trained to maintain the system, change out filters and replace additives in the water.

Ceramic Filtration

Ceramic filters work by extracting dirt, bacteria, protozoa and debris from water as it passes through small pores of the ceramic material. It is usually used in conjunction with other filtration methods such as carbon and colloidal silver. Filtration systems are available as buckets from organizations such as Waterislife and local manufacturers. There are several advantages to using the ceramic filtration system: One, it has been proven effective in the removal of bacteria and protozoa from water. Second, the system is easy to use and is widely acceptable as a purification system. Finally, it involves a onetime-only cost to make. Disadvantages include: Slow filtration time, producing only 1-3 liters per hour for turbid water, no residual chlorine protection which can lead to recontamination and filters which break down easily and must be cleaned regularly.

The Water Purifying Bicycle

The water purifying bicycle system filters water through the pedaling of a bicycle. Bicycle systems such as the Nikkon Cycloclean consist of a purifying case attached to the rear of the bicycle. The pedaling action forces water through a filtration system before being stored in a vessel of your choice. The main advantages of this system include quick purification (up to five liters in one minute), portable and easily accessible in areas where other vehicles cannot reach, and water which can be used for multiple purposes such as cooking, cleaning and drinking. One of the main disadvantages of this system is its relatively high cost.

Personal Filter Straws

These are small flute-shaped portable water filter with internal filtration components such as membranes, iodized crystals and carbon. Filter straws such as the LifeStraw and WaterisLifeStraw filter pathogens from water to make it safe for cleaning. Its advantages include ease of use, ideal for emergencies since it does not require electrical power and it is highly portable. Its disadvantages are low durability (lasting only a year) and the fact that it only purifies drinking water and not water for cooking or cleaning.

Conclusion

The water purification solutions discussed in this article have been highly effective in combating the water crisis in developing countries and in ensuring the delivery of clean, safe and affordable drinking water to communities in affected areas.