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Sewage cycle

  What if the road to a sewage treatment asset was partly made from sewage? As part of my work delivering capital projects for AMP8, I’m challenging every aspect of proposed process solutions — including something as seemingly mundane as concrete. Concrete matters. It has a financial cost, but also a significant carbon footprint. Having spent much of my career delivering carbon-reduction plans for manufacturers and industry, I’ve seen some fascinating innovations in lower-carbon concrete and construction materials. But this one caught my attention. In the Netherlands,  cellulose recovered from used toilet paper in sewage is being used in asphalt for cycle paths. Think about that for a moment. Wastewater treatment works recover cellulose from something we literally flush away — and that recovered material becomes part of infrastructure. Now imagine applying the same principle closer to home: using recovered sewage-derived materials in the access roads and infrastructure needed ...
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  What do squirrels have to do with removing pesticides from wastewater? You may well ask! I’ve been thinking about competitive adsorption for cypermethrin removal and find a useful analogy in red squirrel conservation. Red squirrels are smaller than grey squirrels. That difference in size can be exploited when designing feeders: by setting the mechanism around a carefully chosen weight, food can be made accessible to the smaller red squirrel while restricting access by the heavier grey squirrel.  And that is rather like what happens inside a granular activated carbon filter (GAC) filter. GAC has a distribution of pore sizes. The measures of its absorption quality are iodine number and methylene blue number. The iodine number indicates the carbon's capacity for adsorbing small molecules, i.e the amount of microporosity. Methylene blue is a considerably larger molecule, so quantifies the adsorption capacity associated with larger meso-pores. So they act rather like red and grey...
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Squirrels and methylene blue

  What do squirrels have to do with removing pesticides from wastewater? You may well ask! I’ve been thinking about  competitive adsorption  for cypermethrin removal and find that a useful analogy comes from an unlikely place:  red squirrel conservation . Red squirrels are smaller than grey squirrels. That difference in size can be exploited when designing feeders: by setting the mechanism around a carefully chosen weight, food can be made accessible to the smaller red squirrel while restricting access by the heavier grey squirrel. It is, essentially,  selective access . And that is rather like what happens inside an activated carbon filter. Granular activated carbon (GAC) isn't just a giant sponge with an infinite number of identical holes. It has a distribution of pore sizes. The traditional  iodine number  gives us an indication of the carbon's capacity for adsorbing small molecules and is strongly associated with its microporosity.  Methylene ...
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GAC cypermethrin

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  In Granular Activated Carbon (GAC) testing, iodine and methylene blue serve as  surrogate indicators  representing different classes of target molecules based on  molecular size and pore accessibility . [ 1 ,  2 ] Iodine Represents Small Molecules Molecular Trait:   Iodine (I₂)  is a very small molecule with a molecular diameter of roughly  0.56 nm .  [ 1 ] Target Pore Range:  It represents contaminants that fit into the  micropores  (pores smaller than 2 nm) of the carbon.  [ 1 ,  2 ,  3 ] Represented Molecules:  The  Iodine Number  indicates the GAC's capacity to remove  low-molecular-weight organic compounds  and raw disinfection byproduct precursors. Examples of molecules represented by iodine include: Volatile Organic Compounds (VOCs) Trihalomethanes (THMs) Taste and odor compounds (such as geosmin and 2-methylisoborneol) Chlorinated solvents Chlorine and iodine-like micropoll...
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