System Inspiration

The following clip is what caught my attention on greywater and influenced me to design a greywater phtyoremediation system for Dickinson’s Bio-Diesel program.  I was fooling around on youtube one night and came across this very interesting clip.  It is from a guy in India who is using cat tail plants to clean up his washing machine’s greywater to water his plants on his roof.  Enjoy!

Small scale system used to treat washing machine greywater in India



Contaminant Testing

So in the previous post we established our contaminants.  The next step would be to find ways to test for the levels of each contaminant.  To address the soap problem, I am using Ph strips to see how basic the water is.  I ran a Ph strip test on the greywater this past Friday (Sep 30th) and got a Ph level of 9 which is better than I expected.

Concerning the particulate matter, I’m not too worried about that.  At this point of the process I’m sure the particulate matter will not be of too much concern that it will hurt the plants in the system.  As far as the residual potassium hydroxide is concerned, I’m not too worried about that either.  Most of it has already been reacted with the fuel and any existing small levels of it will be good for the plants.

However I do need to find ways to test for excess methanol and BOD concentrates.  A colleague of mine suggested that I do a flash point test on the greywater to test for any methanol.  The basic concept of this test is to heat the greywater up and bring an open flame to it.  Methanol is highly flammable so if there is any existing amounts of it in the water we should see a spark.  However, I’m a bit concerned with the safety-ness of this test so if there are any other suggestions I will be quite open to them.  As far as the BOD levels are concerned, I am doing research on different tests that I can conduct on the greywater.  If anyone has any suggestions on this I would greatly appreciate it.

As for now, I’ll keep working on what I have and I’ll be sure to keep you all updated.



So the first step in designing a greywater treatment system would be to find out what contaminants are actually in the water.  Based on some basic online research I did on bio-diesel greywater contaminants as well my knowledge on the chemicals/additives used specifically in our shop, I have come up with a list of possible contaminants that I hope my designed system will treat.

Greywater from our shop contains/potentially contains the following:

– Water (Of course)

– Excess Methanol (However we do conduct methanol recovery on our fuel so there should be little to none in our greywater)

-Soaps and Dissolved Glycerin (Result of Lye introduced to create methoxide)

– Residual Potassium Hydroxide (From the kind of Lye we use in our shop.  However potassium is known to be good for plants as a fertilizer)

-Particulate Matter (From food that was fried in the vegetable or cooking oil however very little if any)

-Bio-chemical Oxygen Demanding (BOD) waste (Bio-diesel is known to have high levels of BOD so I wouldn’t be surprised if that too is the case for its waste water)