Last week all of our chemicals arrived to complete our recipe for the NSF 350 – Bathing Water we will be using for testing. With the addition of the test dust and lactic acid that were missing from our first batch the water is bubbly, cloudy, turbidity, tinted brown and has a strong fragrance.
With our new solution we decided to subject it to some physical treatment that would assist us in our on-going final design development. We treated the greywater using various size filters (1.2, 0.7 and 0.2 micron) and a home spiral wound membrane (reverse osmosis). After treatment we performed visual, odor and analytical tests.
Visually – All filters and membrane produced water that was crystal clear to our eyes
Odor – We all stuck our noses in the beakers and were amazed at the variety of odors. Those treated with the various filter sizes still smelled of fragrant soap but less strong than the untreated water. The membrane treated water smelled like PEACHES! None of the soaps smelled directly like peaches… guess that molecule is different than the other fragrances.
Analytical – Our lab has the capability to measure a variety of the required analytical parameters. Those selected for this experiment were total dissolved solids which can approximately be related to the amount of salts in a water sample, turbidity which measure the degree of cloudiness associated with particles that the human eye cannot see and total organic carbon which relates to the amount of organic material remaining in the water. Our findings? The membrane performed better than any of the various filter sizes. The membrane removed more turbidity than the filters having a treated turbidity of 0.3 NTU. The membrane was the only treatment that removed any total dissolved solids with a reduction of about 66%. And the membrane was the only process that was below the Alaska Department of Environmental Conservation guideline of < 10 mg/L total organic carbon, with a treated concentration of about 3 mg/L (with nearly 90% removal).
*Total organic carbon of the NSF greywater was an estimate based on the created recipe not analytical procedure.