Carbon Neutral Water

By Josef Newman

Every day billions of people wake up, walk to the sink and open the taps. Most of them never think of the carbon footprint that water has.

Carbon footprint? It sounds strange to think of water as having a carbon footprint. However, all drinking water is pumped and treated before it reaches its user. In many places where freshwater is limited, water is taken from the ocean and desalinated for drinking and irrigation uses. Desalination is the process of removing salt from water, so that it is drinkable. Desalination is also a major consumer of electricity, and as such, contributes to the emission of greenhouse gases.

There are two major desalination technologies currently in use; Multi-stage Flash Distillation (MSF) and Reverse Osmosis (R.O.). MSF mimics the natural hydrological cycle, evaporating the water and leaving the salts behind, to later condense the freshwater. It was, until recently, the most widely used technology in the field.  Reverse Osmosis technology works by pumping water at high pressure through a membrane, leaving the salts behind and allowing the water to pass through. Due to recent advances in membrane technology, R.O. has become the most prominent form of desalination worldwide. R.O. has one major drawback, in that it requires a large amount of electricity to operate the pumps at the force needed. On a grid powered by fossil fuels, that amounts to a high carbon footprint.

The good news is that new technologies are currently under development that can drastically reduce the carbon footprint of desalinated water.  One new development, stemming from the nanotech industry, is called nanofiltration. Essentially, nanosized molecules act as a filter, allowing water to pass through but trapping salts and other matter behind. This acts much in the same way as current R.O., but with lower electricity needs. The best part is that it’s a complementary process, and so older desalination facilities can make additions so that they don’t become obsolete.

Another technology under research is called Forward Osmosis. It works by adding the water to a unique solution that lets it pass through a membrane naturally, using only 10% of the electricity that Reverse Osmosis uses. The salts are left behind, and the water is easily separated from the solution. Forward osmosis is less commercialized than nanofiltration, but promises to revolutionize the industry.

With all these new technologies available, we still should not forget the technologies we have. Desalination’s carbon footprint is as high as it is because our grid is powered by fossil fuels. Alternative energy can be used to power these plants with no carbon emissions. That’s exactly what was done in Perth, Australia, when the operators of a new desalination plant contracted with a large wind farm to supply 24 megawatts of clean energy, enough to power their plant full time. The result is carbon neutral water using existing technologies.

Similarly, a plant in Carlsbad, California, is currently planning carbon neutral desalination as well. This will be achieved through a variety of mechanisms, from alternative energy projects to carbon offsets and sequestration projects.

The United Nations has said that drinking water scarcity is quickly becoming the world’s biggest problem. While industry works to solve this problem, they must also remember not to create other problems, and follow the examples of the current industry leaders in ensuring our water is carbon neutral.

Water Drought and Gray Water Recycling

Water drought is a weather-related natural disaster; it is caused by a decreased precipitation over an extended period and results in shortage of water reserves and supplies. It has its effect on every aspect of our daily life; there is less water available for growing crops, farming animals, industry in droughts. Droughts also affect our overall environment by destroying animals homes and habitat, causing erosions and increasing the price of food as agriculture is affected by the diminished water supplies.

The households in the US use an average­ of 400 gallons of water per day [source: EPA]. So conserving water by cutting down on the water usage sounds like a great idea.

Here below are some examples of the amount of water we use everyday. So how much can we actually save?

Used	Liters
Taking a Bath	80 Liters
Five Minute Shower (not power shower)	35 Liters
Brushing Teeth with the Tap On	6 Liters
Brushing Teeth with the Tap Off	1 Liters
Flushing The Toilet	6 Liters
Washing Machine	60 Liters
Dishwasher	40 Liters
Car Washing Using a Bucket	10 Liters
Hosepipe/ Sprinkler	540 Liters

IN CA, bans have issued on outdoors watering to cut it by as much as 20 percent.

Solutions for cutting the usage of water can be:

• Running the washing machines only with full loads
• Take shorter showers
• Sweeping the driveways instead of watering

If applied this will conserve an average of1000 gallons consumption/ month.

One of the solutions proposed is “Grey water Recycling” (Grey water is non-industrial wastewater generated from domestic practices like dishwashing, showering, laundry any water usage in the houses except the toilet water and comprises 50-80% of residential wastewater)  to be used for functions as flushing toilets, watering plants.  The good news is that Grey water is easy to treat, it’s becoming increasingly popular for people to collect and reuse in their own homes.

It is mostly used to water plants, 2007, EPA announced that irrigation water is 15% of total water consumption in the United States [source: EPA], the same kind of water we consume for human drinking, places like Golf courses consume way more water

But it is important to note that Grey water is not benign as it contains certain degree of contamination that might/will cause sickness or malaise of used by humans.

• Dishwasher water can contain some rotten food particles,
• Washing machines Grey water can contain:
  1. Useful components like phosphorus and nitrogen used in fertilizers
  2. Harmful components as Bleach which is a hazardous chemical
  3. Sodium salts used as softening agents in some products.  These salts are toxic to the plants as they poison the soil (this can be avoided by alternating watering Grey water and fresh water or spreading gypsum (calcium sulfate) over the soil at a rate of two pounds per 100 square feet about once a month)

• Bath water contains:

1.    Soap that is less harmful since you use it on your own skin which makes bathwater the better water for Grey water plant watering

2.    Fecal matter and dead skin cells

3.    Grey water is alkaline-rich, it’s not suitable for use in watering acid-loving plants

In some states it’s not legal to collect and use Grey water, and in others it’s necessary to obtain permits and observe restrictions first.  In some states it is required that the Grey water systems remain entirely underground and irrigate plants directly at the roots, using the flood method or drip irrigation systems. So it is advisable to use Grey water only for the ornamental plants and lawn and not even spraying or misting it on fruit trees, vegetables or root plants consumed by humans as the roots absorb the harmful components of the Grey water. Grey water should be irrigated only on flat ground and avoid steep slopes where runoff into other yards could be a problem

In my next blog (part 2) I will explore how to collect and recycle Grey water

Cheers,

Sahar Andrade

Sahar Consulting

www.saharconsulting.com

www.linkedin.com/in/saharandrade

www.saharconsulting.wordpress.com

Columnist at EcoChamber

www.ecochamber.com

Energy Effecient Waters in South America

SAN LEANDRO, Calif., Mar 31, 2009 (BUSINESS WIRE) —-Energy Recovery, Inc. (”ERI”) (NASDAQ:ERII), a global leader of ultra-high-efficiency energy recovery products and technology for desalination, was awarded the 75,000 m(3)/day (20 million US Gallons (MGD: undefined, undefined, undefined%)) energy recovery technology contract from Acciona Agua for the Paraguana seawater reverse osmosis (SWRO: undefined, undefined, undefined%) desalination plant in Venezuela. The project is currently under construction and is scheduled for completion in early 2010.

The plant is located in the Paraguana peninsula in the Falcon region in northwest Venezuela, an area considered to be one of the driest places in the country. The project at Petroleos de Venezuela SA’s (PDVSA: undefined, undefined, undefined%) Paraguana Refinery Complex is being designed and built jointly by Spanish water company Acciona Agua and PDVSA. The Paraguana Refinery Complex will utilize approximately 30% of the production capacity, with the remainder supplying a population of 350,000. This will be the largest RO desalination plant in South America and one of the largest plants in the Caribbean region.

For full article, click here.

Half World Faces Water Shortage by 2080

Wong Poh Poh, a professor at the National University of Singapore, told a regional conference that global warming was disrupting water flow patterns and increasing the severity of floods, droughts and storms _ all of which reduce the availability of drinking water. Read more

One of the Largest Public Health Issues of Our Time

As the planet’s once plentiful blue resource gets used up, companies are acting to secure their supply and become more efficient users of water. A business publication from the UK called Ethical Corporation has published an interesting report on this trend, which we’ve pulled excerpts from here: Read more