How to Save Water When Using Dish Washer?

Water saving system for dish washer

We choose to develop a unit that is able to recycle the waste water coming out from a dishwasher so that it would be possible to reuse this waste water on the next washing cycle of the dishwasher and hopefully we could save by this 70% of the water consumed by the dishwasher. 


The reasons we choose this idea:


1) Water is one of the most important and in absence resource in the world. Dishwasher is one of the instruments that consume large amount of water, and it is very important to find way to save the fresh water it used.

2) To reduce the cost of uses of the dishwasher

3) To reduce the amount of dirt that arrive to the POTW municipal systems and create big pollution in the municipal POTW

4) This innovation is a green ecological invention and belong to the clean-tech segment that is needed in order to save and protect our plant   



As students, you are asked to make a device which can be added to a dish washer and it should meet the requirements as follows:

1.Water can be purified and recycled through this device.

2.The filtered dirt is supposed to be processed in an easy way.

3.The whole device should take up as little room as possible.

4.This device is supposed to be both energy-saving and cost-saving.


By planning and implementing this product, students can develop their communication skills through teamwork, innovative ideas through brainstorming and they can also gain hands-on experience through practice and problem-solving abilities through various unexpected circumstances.

Provide an answer by clicking on "Map" and then on "Add an Answer".

Results, Analysis and Discussion

1.  Yin Taoye (16.08.2018 pm 02.00.51)
The cost is the biggest problem

I think that you guys did a great job about explaining your product. We all know that water resource is very precious. However, I don't think your plan can figure out this issue because wastewater contains lots of elements which cannot be filtered easily.  If you really want to recycle the water, its cost is bigger than buying fresh water directly so that the cost is the biggest problem.

2.  Zhang Zhenghong (16.08.2018 pm 02.20.54)
comments from Zhenghong Zhang

As water it's truly a kind of scarce resource in Israel. And as we can see, group 1 provided a fantastic solution to this problem. Moreover, through working out the project by our own group, we also improved practical and innovation ability. Now after careful consideration, I would like to offer some personal advice for reference.
When we were doing the PBL, we had a problem about what on earth we should do. In detail, we didn't really know if we should save water in different ways or just to recycle water. Because in the document, the question is about how to save water. Then there can be many ways to save water. However in the assignment, we were asked to recycle water. Then the method would be limited.To think of another effective way to recycle water in several days can be a little difficult. So at first we were confused about this problem.
Luckily, after asking our teaching assistant and members of group 1, we knew that we can use other ways to save water except for recycling water. We finally made a model that can turn water into mist drops with high-speed air flow. In this way, we can use less water to clean dish.
In all, my suggestion is that it's better for you to make your PBL assignment more clear and exact so that others won't be misunderstanding. 

3.  Ryndin Alina (16.08.2018 pm 03.03.31)
Peer assessment (for group 1)

Dear  Eran Shaleiv, Zixuan Li, Yuxuan Feng and Hui Li,

I enjoyed accepting the PBL mission you designed. I find the water status in Israel and around the world an important issue.

While dealing with the mission I had some comments/ideas you might want to consider:

1. The title of the PBL is:  How to Save Water When Using Dish Washer?

this is a wide issue that can be addressed in many ways. However the assigment is specifically directed to recycle solution. I think the issue presented at the headline evokes much more innovative work and can be more fruitful. 

2. The project has a strong technical orientation. In that case you might want to add a diagram that helps to understand the solution space. For example:

Good luck,


4.  Chen Suya (16.08.2018 pm 04.13.30)
This comment is from ZHANG CHAOAYI for group 1.



A brilliant idea to save the water from the dish washer. It is clever to reduce the pressure to lower the boiling point of water. But there is a problem, sometimes it may cost more energy to reduce the pressure. If we want to save water at the cost of more energy, that is not environmental-friendly.




5.  Chen Suya (16.08.2018 pm 04.56.40)
Comment from Suya Chen in Group 7

 Your video is very interesting, and the idea of filtering and purifying waste water is very good. We were inspired by the model your group made. But I have a small problem. The cost of filtration and purifying water is very high. If this device is added to the dishwasher, will it greatly increase the cost of washing dishes?
To solve the problem raised by your group, our group's solution is to make a spray dishwasher, and the high-pressure spray mist generated by human trampling can be used to wash dishes with high-speed water fog, saving water resources.

History of edits
Edited BY: Hui Li Edit Date: 2018-08-09 18:06:45
Created By: Hui Li Edit Date: 2018-08-09 11:36:19
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