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Benefits Of Grey Water Recycling
Written by Geoff Jones   
Sunday, 17 February 2008 19:00

Introduction

First, let's take a quick look at why it's important to even care about the benefits of something like greywater recycling.  With water being so easily accessible in our homes today it's easy to forget about conservation and why we should care about something like reusing greywater within our homes.  However, although water is very easily accessible for many people around the world, it's not so easily accessible for a very large number of people.  According to WHO/UNICEF 2005, over 1.1 billion people (yes that's BILLION) do not have access to safe drinking water.  Hard to believe isn't it?  Something that we sometimes take for granted and is one of the most precious resources for sustaining life is clearly not taken for granted all over the world.  And to think, we use drinking water to flush our toilets. 

Closer to home (for those of us in N.A.) we should also consider a few more facts about water.  Even though approximately 70% of the world is covered with water only 2.5% of that water is actually fresh water.  Fresh water is the water that is suitable for drinking and bathing etc.  Of that 2.5% of fresh water more than 1.5% of it is locked in glaciers which leaves less than 1% of the water in the world accessible through lakes, streams, rivers and ground water sources.

Freshwater Statistics.jpg

In N.A. the Great Lakes supply water to more than 33 million people (approx. 9 million Canadians and 24 million Americans) yet only 1% of the waters of the great lakes are replenished each year by rain and snow melt.  Consider also the fact that without water there is no life, human or otherwise, and it should be quite clear that water, and the responsible use of water, should be on everyone's mind. 

Think about this.  An average family of 4 uses between 45000 and 62000 liters of water a year to flush toilets.  According to the UN Water for Life initiative, in a developing country 20-30 liters of water per day is sufficient to address basic human needs.  So, the water used by a family of 4 to flush toilets over the course of 1 year would be enough water to address the needs of about 8 people for 1 year in a developing country.  Think about that for minute.....

Saving Water Through Grey Water Recycling

One of the biggest benefits of using greywater is the reduction in water demand from your municipality, well, or whatever water supply you draw water from.  The whole concept behind grey water use is to reuse water that was already used once for bathing or washing your clothes and to use it again for applications that don't require potable (suitable for drinking) water.  There are other applications for greywater that go even further by using more advanced treatment technologies that can essentially return your greywater to potable water quality but we'll focus here on the simplest approaches for now.  By using your greywater for applications that don't require potable quality water you essentially get twice the value out of the water you bring into your home/business.  This means, for example, that instead of using 50 liters a day to shower and 40 liters a day to flush your toilets, you can use 50 liters a day to shower, and then use that water again to flush your toilets.  Grey water can also be used, providing local by-laws and regulations permit (and please always check this first and follow the building codes in your area), for irrigation of non-edible plants and vegetation.  Why not?  There  is only a little bit of soap residue in typical bathing water and if you use environmentally friendly products the contaminants are even less.  Why not use that water for shrubs, trees or plants instead of using drinking water. 

Reducing Sewage / Septic Flows Through Grey Water Recycling

One of the other benefits of a greywater recycling system is that not only can it reduce your water supply demand but since you are reusing the water for more than one application you will also recognize a reduction in sewage/septic wastewater.  This might not seem important to you but if you have a septic system and you can reduce the load on that system it may mean added years of service and ultimately savings in your pocket.  If you don't have a septic system you may think that there really isn't any benefit to you.  We'll, most areas not only charge you for the water you use, but they also charge you for the sewage you generate.  So, by reducing your water usage, and subsequently reducing your sewage you are saving money too.  In addition, although this may not be a direct benefit that you can see on your monthly bill today, the more people who reduce their water usage, the less water that needs to be treated by the municipal water treatment facilities. This in turn may help to control or minimize future expansion, which keeps municipal costs down.  Ultimately, keeping these costs down benefits everyone as they are either realized through increases in water rates, or property taxes.

Reducing Power Consumption Through Grey Water Recycling

What are you talking about? I'm using less water, not using less electricity.  Is that what you're thinking?  We'll, sometimes we need to look beyond the surface benefits to realize and see the underlying benefits of water conservation.  Let's look at it from the perspective of water treatment.  By now I think we would all agree that a greywater recycling system can save water, and also reduce sewage, correct?  OK, let's now consider that treating water involves many electrical pieces of equipment and treatment technologies.  So, by reducing the water we use and sewage outflows we are in essence saving energy by reducing the water that needs to be treated and pumped to our homes. 

A recent publication by the Environmental Protection Agency (EPA) indicated that letting a 1.8 gal/m tap run for 5 minutes has equivalent energy consumption usage to running a 60W light bulb for 14 hours.  Now, I don't know all the details behind how they made this correlation, and what assumptions they made in there analysis, but I can see that the basic idea of reducing the water that needs to be treated and pumped saves electricity to be a sound perspective.  If we take this example the EPA provided (and let's not fight over how  they arrived at the numbers right now) and do a little quick math it means that for every liter of water we save, we save approximately 25 watts of electricity ((14hours*60watts) / (1.8gal/min*5minutes*3.78) = 24.7Watts/L).  Doesn't seem like much does it.  But, if you consider the water we use over the course of a year it might seem like more.  Let's take a look:

Consider toilet flushing.  If we flush 5 times per day (statistics typically say 5-7 times per day) and have a 6 liter per flush toilet, we could save 30 liters of water per day by using greywater to flush instead of potable water.  We would also save 750W (30*25W) per person by saving that 30 liters.  If there are 4 people in your home, saving the same amount of water you could save 3kW per day.  Consider this on an annual basis and buy using a greywater system you would save approximately 1.095MW (3kW * 365), or 1,095,000 kW per year.  Now, you won't see this as savings on your electrical bill today, but maybe, sometime in the future, there will be a link between water usage and electrical costs.  It won't necessarily be seen as a direct energy savings but I'm sure that the cost of electricity goes into the budget for municipal water treatment facilities and is a factor in determining water costs at some level.

Saving Money Through Grey Water Recycling

Sure, at today's rates it may take up to 10 years to recoup the costs of installing a greywater system, but don't forget that in many areas we are seeing increases in both water and sewage rates year over year.  I'm not big on seeing my utility bills go up either, but the reality is that they are, and if history has shown us anything with electricity and heating, water rates are comparatively low and studies have already shown that when we pay for what we use in general we are more conscious of conserving than when the costs are low.  Couple this with the aging infrastructure and repairs needed over the next 10 years in many areas in Southern Ontario and thepayback will get smaller and smaller each year.  It won't be long before your system has paid for itself, and your putting money in your pocket every year.  The biggest benefit of all is knowing that the choices you've made are having a positive impact on the environment and our children and grandchildren will thank us for that.

Protect Our Resources Through Grey Water Recycling

Significant population growth continues throughout the world, and the growth in Southern Ontario continues at significant rates as well.  With population on the rise and industrial growth steady, the strain on our water resources is becoming more and more visible.  It's everyone's responsibility to make decisions today that consider the relationship we have with our environment, and the importance of ensuring that generations to come can enjoy the beauty of this planet. 

Over the past 100 years the global population has increased from approximately 1.5 billion people to over 6 billion.  If we remember the initial paragraphs of this article anything that we can do today to reduce our impact on the environment is helping to secure a bright future.  Helping protect our precious water resources will also ensure that future generations don't look back and wonder why we didn't do anything when we could see the impact our actions were having on the environment.  It feels good when you start to make decisions and try to consider the longer term impacts of how we live knowing that this simple changes could make a very big difference for our children and grandchildren.

Comments (6)add
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Certification
written by Cathy , August 11, 2010
Who would be qualified to install a grey water system? What certification do they require, and where can you find training information for installation?
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Geoff Jones
RE: Reused water and cleaning
written by Geoff Jones , April 26, 2010
Hey Tammy,

Most systems existing in the world today perform some form of treatment to prevent odors in the toilet. For example; some systems use filtration and chlorine disinfection, some biological treatment and UV and many other combinations. All these are done to ensure the greywater in your toilet is clean and odor free. Just make sure you get a properly designed system that takes these needs into account.

FYI - try using the discussion forums as they provide a better interface for ongoing discussions like this one.

Have a great day.
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Reused water & cleaning
written by Tammy , April 23, 2010
Does using recycled grey water make the toilets dirty faster? I don't want to be cleaning the toilet twice a day!!! And does the water have any smell?
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Water Recycling
written by Rhys , August 11, 2009
I need to know what the prosess is for a raw sewage recycling plant.
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Geoff Jones
Please Clarify what you need help with
written by Geoff Jones , May 11, 2009
Hello Jenny,

Commenting on articles is intended to allow for sharing of views and opinions relative to the article content.

Is there something specific you need help with? If you have a question please post it in the forums and we would be more than happy to try and help. Just saying the site doesn't help doesn't tell us what you need help with or allow anyone else to benefit from your question (which other people may also have).

thanks,
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DOESNT HELP
written by jenny , May 11, 2009
kaay this site doesnt help at all !!!!!!smilies/cry.gif
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Last Updated on Friday, 01 May 2009 15:41