A non-partisan, neutral perspective supporting diversity in the color of water

Saturday, December 3, 2011

Not the Kitchensink Again, Redux

A quick examination of the Geography of Greywater map (scroll to bottom) reveals the heated controversy over the integration of the kitchensink wastewater into the greywater portfolio across the US (some "oldies but goodies" postings here and here, just to get started). Heck, even states that legally defined the kitchensink water in the greywater portfolio have subsequently removed it from the greywater portfolio in their rules and regulations to "protect the public" (Oregon). The rationale is that this is dangerous stuff we are creating in our homes (yes, we ultimately control what goes into our kitchensink, so the fear is FONEY). Much of the fear is based on a very limited dataset of what is in the kitchensink wastwater. But new research reveals that there may be other sources of greywater that were considered "safe" but now may be less safe.

Take for example, this open source article titled Characterization of greywater by appliance - Pattern of discharge along the day by Portuguese water scholars Cristina Matosa, Ana Sampaiob, António Sampaio Duartec, and Isabel Bentesa. Here are some of their "pollutographs" of greywater quality per domestic device. The first one shown here is the number of discharges per person through the day - this is the first time I have seen the water use data broken down by hour in the day. No surprises - peak discharges coincide with when we eat and it appears that I am not alone with the midnight trip to the WC.

But note importance of the kitchensink discharge and the number of discharges each day by appliance in the next diagram.

And then let's examine the coliform bacteria counts in this table since this has traditionally been the metric used to display the danger of reusing kitchensink wastewater. Hmmm, the threatening fecal coliform counts are larger in the bath and dishwasher water than the kitchensink wastewater.

The authors' conclusions? The proposed approach can be used to derive dry weather flow inputs to water quality. It also provides a mean to assess the impact of changes in household water consumption.  
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In developing the multiple hypotheses, the effort is to bring up into view every rational exploration of the phenomenon in hand and to develop every tenable hypothesis relative to its nature, cause or origin, and to give to all of these as impartially as possible a working form and a due place in the investigation. The investigator thus becomes the parent of a family of hypotheses; and by his parental relations to all is morally forbidden to fasten his affections unduly upon anyone. In the very nature of the case, the chief danger that springs from affection is counteracted.
~ Grandfather of modern hydrogeology, 
Thomas Chrowder Chamberlin

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