Ask Umbra on food disposal 3

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1. 

   WaterConsNYC Posted 6:00 am
   15 Jun 2009

   My ever-growing crush on Umbra has only been increased by the best description of a a septic system ever, including the evocative "greasy residues providing an icing atop it all."  As usual, the analysis is spot-on although in places with sewers the issue is little bit more complicated.  I work for a major eastern US city that sits at the mouth of a river and has two baseball teams.  Disposals were largely illegal there for years due to concerns about the sludge blocking sewers and increased Biological Oxygen Demand resulting in increased nitrogen inputs to receiving waters.  The sanitation folks, OTOH, were concerned about mandates to implement high-rise urban composting and their perception of the joy that would bring to our local arthropod and rodent residents. For them, disposals meant sending food waste to wastewater treatment plants where the sludge would end up as compost, fulfilling the original recycling mandate without bugs and rats.  Since even with a 25% reduction in water use since 1990 our wastewater is still relatively dilute, the BOD issue was argued to be secondary.  Our studies showed that while medium-scale use of disposals would not have significant wastewater impacts, greater implementation levels would result in unacceptable nitrogen inputs.  In any case, in dense cities with sewers the issue has another dimension or two.  

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2. 

   Zephaniah Posted 10:43 am
   15 Jun 2009

   A frugal foodie, I abandoned my worm bin a decade ago for a patch of dirt and a shovel.  Now we just bury our kitchen scraps in a 4' by 4' patch of dirt behind a bush. We save peelings, cores, grounds, stems and paper napkins in a bowl covered with a plate. Every other day we take them outside, dig down two shovelfuls, dump the peelings, chop them a bit with the shovel, replace the dirt, and whack the site with the back of the shovel so the dirt is firm. In the couple weeks it takes to complete a circle of burying sites, the scraps turn to dirt, (except avocado pits and corn husks which take a bit longer.) There is never a smell or a digging critter, unless we don't dig deep enough or  don't firm the dirt on top, or accidentally include meat, seafood or milk. Eggshells are fine, but in the summer I crush them and sprinkle under lettuce to stop slugs.In the spring, we trade a couple wheelbarrows of dirt from this site for dirt at our vegetable patch, which then does not need fertilizer. When we got new  kitchen appliances twenty years ago, I did not have a disposal installed because of information that little bits of food in  sewage eventually decomposes in the water where treated sewage is dumped, and as it decomposes it sucks oxygen that sealife needs to live, resulting in dead zones. In the last couple years scientists have reported growing dead zones in Puget Sound, where our  sewage ends up. I wonder if disposals are a factor. In Seattle now we pay a tiny fee to have kitchen scraps  picked up with garden clippings. Hopefully people will use their disposals less and let their scraps return to the land. 

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3. 

   Perry525 Posted 10:45 am
   15 Jun 2009

   Celia, the problem is probably worse than others have mentioned.The bacteria in septic tanks, the things that change our waste into carbon dioxide and methane gas, do not like being cold! They are most happy when living at a temperature of 95 ish.Dumping loads of water in the septic makes them feel ill, cold and miserable, whats more it stops them from doing their job = changing that 55 grams of solids that we deliver on average every day into gas and reducing its bulk considerably. This slow down leads to the septic filling up much quicker than normal.And you know what that means! Lots of money spent on having it emptied.Make sure that as little cold water gets into the tank as is possible.Perry

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