Dual Flush Toilets

1 What?

This action is a knowledge campaign to make IES Barcelona students aware of how to properly use dual-flush toilets.

2 Why?

IES already has the infrastructure to save a great deal of water through proper usage of the dual flush toilets but as indicated by responses in our sustainability class, most students are unaware of how the toilets work.
These toilets have two buttons: one is for flushing liquids and the other for solids. Respectively, the buttons use 0.8 and 1.6 gallons/flush. By making students aware of the differences between the buttons and encouraging proper use of the toilets, we can have a huge impact on water consumption. This will improve the environment, relieve stress on the sewage systems, and save IES money on the water bills. These savings could then be used to promote other sustainable actions.

3 How?

This action is fairly simple to implement. We could put signs in each of the bathroom stalls informing users which button is which and the amount of water that is saved by using the low-flush option. The signs can have information on them about how much water one person can save in a day and then how much the entire school can conserve.

This is a very sustainable action because the signs can be held over between semesters. The data will not change. If the signs become damaged, it would be easy to have a PDF accessible by IES staff to simply replace the signs.

4 References and Links


5 Students Involved in this Action

Sarah Gold (leader)
Grace Pomeroy
Christina Vilmar

The tasks to fulfill this action:

1) Present idea to student council - Sarah Gold
2) Research the impact of this action (liters of water saved per day/semester and the cost savings for IES)- Christina Vilmar
3) Design different signs with facts on them (make PDFs available to IES) - Grace Pomeroy
4) Hang signs - Margarita volunteered to do this
5) Finalize report - Sarah Gold


Sign has been emailed to Margarita (April 16th) who is going to laminate and post the signs in the bathrooms by Monday (April 19th).

Research and Calculations

General Information:
-rising cost of water and governmental regulations are incentives
-two button system selects the water volume of each flush: half flush for liquid and full flush for solid waste
-widely used in Europe, Australia, and Asia
-standard toilets use a siphon method where a high volume of water enters and pulls the waste and water down the drain
-dual flush toilets use a larger hole at the bottom of the bowl and a wash-down design to push waste down the drain. Because this doesn’t use a siphoning action, it uses less water per flush
-the dual flush toilet can save up to 68% more water than a conventional low flow toilet

-does not clog as often
-most modern dual flush toilets use ~3 L for liquid waste and ~6 L for solid waste
-old toilet styles used 19 L for every flush

-the toilet unit is more expensive to buy
-the toilet bowl is harder to clean(occasional streaking)

Impact of Dual Flush Toilets
Monetary Savings Calculations:
-On average, people excrement solid waste once a day, and liquid waste 6-8 times per day
-On average, Spain charge €1.81/m3

Assuming 450 people use IES restrooms, on an average of 4 times a day for the 72 days of the spring semester, IES would save €527.79 if everyone used the toilets correctly instead of incorrectly.

This calculation is made on several assumptions. It is based on an average of 450 people using the bathrooms, assuming an average of 1 solid and 3 liquid excrements per day at IES for the 72 days there are class in the spring. This is also assuming the toilets operate with 3L/ liquid flush and 6L/ solid flush. The amount saved is assuming everyone uses the full flush for all 4 flushes before, and then everyone uses the half flushes for 3 of 4 flushes after the information is distributed.

Based on these calculations, IES will use 486,000 liters of water for its toilets instead of 777,600 liters if the toilets are always flushed using the large flush (as is likely right now). This is a savings of 291,600 liters of water each semester! (That is 77,033 gallons.)

-- >Go to Dual Flush Toilet file under File Gallery for a copy of the Flyer that will be distributed throughout IES: DUAL FLUSH TOILETS.docx:

 Assignment 8: Peer review form

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Items found: 1
How important?How urgent?How feasible?How far?How well justified?How well presented?Overall gradeReviewerNotes from the reviewer
4455555mtrejoVery nice thing to make the students at IES aware of, especially with Barcelona's water problems

Page last modified on Wednesday 04 of April, 2012 17:13:35