Wednesday, March 16, 2011

From sewage to fertiliser

As chair of Stockton Council's Environment committee I attend meetings of Environmental Protection UK, and today's meeting was held at Northumbrian Water's Bran Sands site.  A presentation on how the site operates and then a tour were both very interesting.  It's a site which takes re-use and recycle to the extreme!  Being built on top of a capped landfill site it doesn't have waste water draining away but has it all collected and reused.  Sewage sludge is brought in tankers, mixed with water to make exactly the right balance of solid and liquid, heated to kill bad bacteria, cooled to the optimum temperature for good bacteria to work on it, dried out to form a top quality soil conditioner.  Heat from the process is used to apply heat where needed.  Biogas produced by the digestion produces about half of the power needed on the site.  Water is reused and recycled almost ad infinitum.  The product is used to fertilise fields and helps to keep down the cost of producing rape seed oil and barley in particular.
The weather was cold and misty, so photos were uninspiring, but there's one here just to give a feel for the scale of the plant.

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