We lived on a small Caribbean island for 6 months. Our house was propped on stilts above the water, next to a white sand beach and about 100 meters from a lush jungle. Waves sloshed rhythmically under our house. We listened to howler monkeys and a myriad of birds screaming at all hours. There were no roads or cars on the island, only a small footpath running along the coast.
Yes, at first glance it all seems idyllic, a paradise, but f you look a bit closer though the cracks start to show.
An island out of balance
Tourism had become the main source of revenue and almost overnight this former pineapple and banana plantation had garnered millions in investment. Condos and resorts sprouted up everywhere, and there was even talk of clearing out some of the jungle in order to create a world class golf course. The fisherman stopped fishing once they realized that boat tours and water taxi services are more lucrative and usually less smelly and strenuous. The result? Too many motor boats speeded back and forth, leaving gas and oil in their wakes. This pollution in turn had a deleterious affect on the fragile reef systems as well as the local animal fauna.
This ecosystem was not meant to support so many thousands of people.
No sewage treatment facilities meant entire areas off the shore were no go zones and on very hot days the smell in some neighborhoods was almost unbearable. No proper water treatment plants meant that the municipal water supply was unfit for drinking. Those who could afford it bought bottled water for drinking, creating a glut of plastic bottle waste as well. Even so, there was not always enough fresh water to support so many people. In fact, one year the US Army Corps of Engineers had to bring a tanker ship full of fresh water to meet the water needs of the community.
This island is a microcosm of how we mismanage our global water resources on a regular basis. We build and build until we reach unsustainable levels. In most of the world, potable water sources will become a major resource issue in the next 20 years if they are not already. The National Academy of Engineers predicts that by the year 2025 almost 45% of the world’s population will live in water stress zones.
How can we alleviate this level of stress on our water resources?
DESALINATING SEA WATER
Almost 99% of the water on Earth is located in the oceans and intertidal zones. Pure water can be extracted but at a very high cost and with yields too low to make a large dent in quenching the demand for clean water. Reverse Osmosis Water Filtration is one of the most effective ways of separating particulates and larger molecules like salt from sea water. High pressure is used to force the water through a semi permeable membrane. This can be made of all sorts of materials like sand, charcoal or more exotic stuff.
The problem is that it takes a lot of energy to make potable water and thus lots of money. Researchers at MIT have invented a membrane made out of graphene that is only 1 atom thick, about 1000 times stronger than steel and possesses pores that only pure molecular water can pass through. Since it is so thin, water can pass through the membrane with very little pressure and much less energy. The graphene membranes can be incorporated into existing industrial facilities and are relatively inexpensive to produce.
I can imagine nano cloth being made out of this material and used in less developed or isolated environments to scoop the water up and use gravity to filter the water.
RECYCLING GREY WATER
Water can be used more than one time before being discarded or sent to waste water treatment plants. The water that you use to take a shower, wash your hands or dishes can be collected and used for other purposes. For example, you can use it to water your garden, wash your car or flush your toilet. Or what do you think of using laundry water to grow tomatoes?
Already water prices have become sky high in some cities. You can expect to pay more than $250 a month for water if you live in house in a city like Atlanta, Georgia. Major population increases along with changes in weather patterns have strained the regions ability to provide enough water for this city. As people become more interested in conservation and water starts to become much more expensive retrofitting houses to incorporate grey water will become more of an option.
INVESTING IN NEW SEWAGE TREATMENT TECHNOLOGIES
The dangers of releasing raw or partially treated effluent into the environment are many fold. Eutrophication can be one result. It occurs when the microbes living in the runoff use up the oxygen in the surrounding water and literally choke all other animal and plant species in the area. Another result can be the contamination of underground aquifers with bacteria and other agents that are dangerous for consumption.
The key here is to not only be able to filter out clean water but also to be able to collect and reuse the nutrients found in waste. Phosphorus and nitrates found in water water can be reused as fertilizer for agricultural endeavors. Microbes are also an extremely important part of the process as they naturally break down the solid waste. They can also be incorporated to make bioreactors that can create energy to help fuel the whole treatment process and even produce surplus energy.