The case for mandatory composting - It works in San Francisco. And it could work in Boston.

[OKIsItJustMe]

http://www.boston.com/bostonglobe/magazine/articles/2010/03/21/the_case_for_mandatory_composting/

Perspective

The case for mandatory composting

It works in San Francisco. And it could work in Boston.

By Aubin Tyler
March 21, 2010

Living in the country, I have the luxury of a backyard compost pile. Right now it’s overflowing with acrid slop, but eventually it will yield dark, rich soil nutrients for the garden. If my potato peels, leftover rice, and parsley stems had been buried in a landfill, deprived of sun or air, those same scraps would have given rise to methane, a potent greenhouse gas that contributes to global warming.

Nationwide, there’s a lot of potential in all that slop. In 2008, Americans generated nearly 32 million tons of food waste, and less than 3 percent of that was composted, according to the US Environmental Protection Agency.

Scattered households with compost heaps won’t make a dent in this problem. But local governments can, and should. Last summer, San Francisco passed the first large-scale municipal composting law in the nation. (Seattle actually began mandating composting earlier, but it exempts businesses and apartment buildings.) Today, San Francisco collects 500 tons of food waste a day, picking up from 225,000 homes and apartments and 7,000 businesses. Scofflaws can be punished with fines from $100 to $1,000.

On pickup days, kitchen scraps get dumped into tightly covered green curbside bins, alongside black ones for trash and blue ones for recyclables. Squeamish customers can line their compost bins with compostable bags. The food waste goes to a processing facility, where it’s turned into high-grade compost. That, plus recycling, is expected to keep about 75 percent of San Francisco’s trash out of landfills this year. For 2020, the goal is 100 percent, or zero waste, which to many people would have been unthinkable not that many years ago.

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[Statistical]

1. Composting still produces GHG no way around that.

I see value of composting more in sustainability, reduced landfill usage, etc. Composting isn't going to solve GHG issues though.

[OKIsItJustMe]

3. Different methods of composting produce different results

http://www.epa.gov/osw/conserve/rrr/composting/pubs/

http://epa.gov/climatechange/wycd/waste/downloads/chapter4.pdf">Solid Waste Management and Greenhouse Gases: A Life-Cycle Assessment of Emissions and Sinks - Chapter 4. Composting (PDF) (15 pp, 278K)
Presents the results of an in-depth analysis to determine the net GHG impacts of composting yard trimmings and food discards.

[kestrel91316]

4. Aerobic composting produces virtually NO methane, compared to

anaerobic fermentation (swamp muck). This is why compost piles need water, but NOT TOO MUCH, which keeps air from circulating.

Furthermore, biomass from food is carbon-neutral: the food and grass and such that goes into the pile was atmospheric CO2 a short time before.

I know a bit about anaerobic vs aerobic processes - they covered a lot of that in my university Microbiology of Water and Sewage class. And I worked for 3 1/2 years in a university soil microbiology lab........

[OKIsItJustMe]

5. According to the EPA PDF (cited above)

http://epa.gov/climatechange/wycd/waste/downloads/chapter4.pdf

...

Research suggests that composting, when managed properly, does not generate CH₄ emissions, but it does result in some carbon storage (associated with application of compost to soils), as well as minimal CO₂ emissions from transportation and mechanical turning of the compost piles. In order to maintain consistency with other chapters in this report, EPA selected point estimates from the range of emission factors—covering various compost application rates and time periods—developed in the analysis. The point estimates were chosen based on a “typical” compost application rate of 20 tons of compost per acre, averaged over three soil-crop scenarios. The carbon storage values for the year 2010 were selected to be consistent with the time between onset of the program and carbon storage effect as simulated in the forest carbon storage estimates presented in Chapter 3 of this report. Overall, EPA estimates that centralized composting of organics results in net GHG storage of 0.05 MTCE/wet ton of organic inputs composted and applied to agricultural soil.

...

4.1.1 CH₄

To research the issue of CH₄ emissions, EPA first conducted a literature search for articles on CH₄ generation from composting. Because CH₄ emissions from composting are addressed only occasionally in the literature, EPA contacted several composting experts from universities and USDA to discuss the potential for CH₄ generation, based on the nature of carbon flows during composting. The CH₄ analysis presented here is based on their expert opinions.

The researchers EPA contacted stated that well-managed compost operations usually do not generate CH₄ because they typically maintain an aerobic environment with proper moisture content to encourage aerobic decomposition of the materials. The researchers also noted that even if CH₄ is generated in anaerobic pockets in the center of the compost pile, the CH₄ is most likely oxidized when it reaches the oxygen-rich surface of the pile, where it is converted to CO₂. Several of the researchers commented that anaerobic pockets are most apt to develop when too much water is added to the compost pile. They noted that this problem rarely occurs because compost piles are much more likely to be watered too little rather than too much.

EPA concluded from the available information that CH₄ generation from centralized compost piles is essentially zero.

...

[happyslug]

6. The main GHG concern is Fossil Fuels NOT recycle green house gases

Lets keep int mind the main source of Green house gas, fossil fuels. Much of the excess carbon (and to a degree Methane) have been kept deep underground and thus OUT of the atmosphere in the form of Natural Gas, Coal and Oil for millions of years. Global warming is NOT being caused by Methane from Compost piles (or even cattle) but the release of these "Captured" green house gases. The atmosphere can survive quite well with increase composting, the atmosphere having been converting Carbon and Methane to solid green vegetable matter and then back into Carbon and Methane for Millions of years. The total life cycle of such conversions are while known (But vary as to time and place) but more or less constant over the last several million years. The problem is NOT the composting, but the actual growing of the crop (which uses fossil fuel), transportation of the food to your local market, transportation to your home for consumption (most of which is done by fossil fuel) and the movement of the material to be composted to the central compost and then to be reused (Which is fossil fuel dependent UNLESS used in the home where the food is used i.e. you eat, compost the waste and then used the compost yourself).

My point is the compost itself, its release of carbon and methane, is of minor impact on the world (and so minor that the earth can handle it without any assistance). The problem with Green House Gases is the release of Carbon that has been kept within the earth and away from the atmosphere for millions of years (in the form of Coal, Natural gas and Oil) NOT Carbon and Methane that is constantly being captured by plants and then released by animals. The latter the atmosphere has been handling for millions of years, the former is what is causing the Green House Effect.

For more on Carbon fixation:
http://www.john-daly.com/co2-conc/ahl-co2.htm
http://en.wikipedia.org/wiki/Carbon_sequestration

[stray cat]

2. Oh no - Not a Mandate!