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  Sierra Magazine
  November/December 2006
Table of Contents
Cheap Food Nation
Produce to the People
From Cotton to Collards
Ten Ways to Eat Well
Secrets of the Supermarket
Truth in Labeling
Home Cooking
Ways & Means
One Small Step
Lay of the Land
Good Going
The Green Life
Hey Mr. Green
Sierra Club Bulletin
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hey mr. green
Mr. Green's November 1, 2006, Mailbag

Rants, raves, and righteous ideas from our readers

Mr. Green loves hearing from his readers, whether they think he's a green guru or an eco-idiot. Periodically, he'll post some of his favorite exchanges online. To join an ongoing debate--or start a new one--e-mail

Sewage and Civilization

Where would advice columnists be without smart, well-informed readers to dispute our ideas and temper our excesses? In the July/August issue, I got carried away while criticizing garbage disposals, saying that "pulverized crud whirled through disposals and into wastewater increases the level of pollutants, requiring extra treatment before the effluent is safe enough to be released." Well, that's not necessarily the whole story, as Rob from Denver points out:

"I believe your assessment of the garbage disposal was way off. Food scraps that run down the drain go through your municipality's waste-treatment digesters, which break them down into methane (often scrubbed and reused as a clean, climate-friendly replacement for natural gas) and an inert sludge that can be used as a soil treatment. In fact, sending your apple core through the disposal is a low-effort way to accomplish much the same thing as composting, with the additional benefit of taking much of the methane (a greenhouse gas) that would have escaped into the atmosphere during the composting process and harnessing it as an energy source.

"As for the 'extra' level of pollutants you talk about, the benign organic food waste we send down the drain hypothetically reduces the overall level of pollutants through dilution. (Cadmium, the worst pollutant in sewage, generally isn't found in table scraps.) In the end, people should feel pretty good about using their disposals. Of course, if your city has a green-bin program [to collect and process solid organic waste] like Toronto's, it's better just to use that."

Dave from Madison, Wisconsin, was equally critical, though more plainspoken:

"Lots of green people freak about digested turds in sewage residue, but it was the invention of the sewage system, more than anything else, that allowed civilization to flourish. Imagine life without sewers! The other 'solutions' are frankly horrific: burial in landfills or burning.

"My strong opinions on the subject come partly from watching the Madison sewer system handle this stuff. It's tested for 120 contaminants and, when knifed into soil, has absolutely no odor. Crops love the stuff, as numerous tests prove. Adding humus to soil reduces water erosion and promotes soil health. Degraded or eroded soil--even slag piles from coal mines--can be rejuvenated with massive doses of biosolids. It's recycling on the grand scale. There is no excuse for allowing lead, cadmium, etc. to enter sewer systems and contaminate the residue. Environmentalists ought to love sensible, responsible recycling of waste products."

I have utmost respect for sewage systems (regular readers may recall that I ripped President George W. Bush for withholding funds to construct or upgrade them), so let me clarify. When you consider that a billion people in the world do not have access to clean, safe water and that 4 million die every year from waterborne diseases, you can begin to comprehend the immense contribution of sewers to humanity.

Vastly improved sewage systems in the United States are one of the great and largely unheralded victories of the environmental movement. In the 1970s, the newly formed EPA started to require "secondary treatment" of sewage, which involves letting bacteria digest it to greatly reduce threats to health and the environment. Because the EPA funded about 70 percent of the costs of these improvements, local governments were able to carry them out relatively rapidly. The amount of hazardous materials like cadmium and other heavy metals in sewage has also been greatly reduced over the past 30 years.

Many municipal sewage-treatment plants do recover methane as an energy source while also producing sludge, known by the more user-friendly name "biosolids." As Rob points out, biosolids are a good source of organic fertilizer, and sewer systems now generate more than 7 million tons of them a year in what amounts to a colossal recycling effort.

Not all systems, however, do the full job of recycling, so if you want to be as virtuous as possible, you should find out what your city does before whirling food down the drain instead of composting it. If you don't compost, then it's better to grind up scraps in the disposal than to scrape them into the garbage. The big exceptions are fats, oil, and grease (a.k.a. FOG), which can clog up drains in the home and create various problems for sewage systems down the line.

My main point, however, remains valid, so let me harp on it again: A vast amount of food waste--more than 500 pounds per household per year--doesn't go to state-of-the-art sewage plants or get composted either.

Biodiesel and the Downfall of Civilization

Hey Mr. Green,
I read your responses to readers' comments about biodiesel but was confused about your overall opinion. Which is more environmentally friendly, a car run on home-produced biodiesel or the same model run on gasoline? --Confused in West Olive, Michigan

Hey Confused,
Thanks for the question. I seem to have confused a lot of people on this one. Home-produced biodiesel generates fewer global-warming emissions and less pollution than gasoline does. But biodiesel will quickly lose its environmental edge if it is produced using chemical-intensive, erosive, or unsustainable farming methods.

Call me a nervous Nellie (oh, how I miss those pointed insults from the inimitable Spiro Agnew), but I have this dreadful vision of an American countryside completely covered with industrial-strength corn and soybeans, where peons toil for starvation wages on big industrialized farms to grow food for cars instead of people. Out of this appears a bleak, blighted landscape of parched soil worn down to its limestone bones by biofuel production, with corporate and individual heads still buried in the sands of the road-warrior wasteland we've created.

I'll probably be dead before this happens but am troubled to imagine how it might damage my beloved cemetery plot (see the next mailbag for more on this topic). I'm not sure we're immune from the reckless, selfish, and vainglorious use of soil, water, and energy that has taken down quite a roster of civilizations, though our democracy does offer some protection. (For more on the unhappy topic of ecological collapse, reads the works of George Perkins Marsh, Clive Ponting, Jared Diamond, and Anne and Paul Ehrlich--or, for a more literary and ancient view, the stirring Epic of Gilgamesh.

Which leads--finally--to my main point: My warning not to expect a magical solution from biodiesel wasn't intended as a criticism of the fuel itself. While it's fine to use biodiesel, it's a big mistake to think it can solve our energy problems, because this country's cropland simply can't produce enough to come anywhere near replacing the 850 million gallons of oil we recklessly burn every day.

So my argument is more psychological than technical: We shouldn't pin such high, unrealistic hopes on biodiesel (or any other cure-all) that we ignore far more effective means of reducing fossil-fuel consumption, the single most important of which is to force state and federal politicians to pass laws requiring vastly improved fuel economy in vehicles and greater efficiency in all appliances.

There's also an important personal dimension to this. Many people continue to overuse cars because they have a pie-in-the-sky faith in technological fixes, a fantasy that absolves them from worrying about our fossil-fuel problems. It's troubling to hear well-meaning environmentalists say, "Well, with biodiesel and ethanol, we'll be OK." You might as well just drink all that ethanol as pretend it will save us. We have to get more realistic and make the kinds of political demands now enacted into law in California to cap greenhouse-gas emissions.

Individually, we must reduce car use and walk, take mass transit, or ride bikes; make our homes as energy efficient as we can; turn off lights and appliances when not in use; and turn the heat and air-conditioning down (especially at night). When we do drive, we need to stick to the speed limit and make sure our cars are well tuned and our tires properly inflated. These simple lifestyle changes will yield many times more energy than all the biodiesel our great land is capable of producing.
Mr. Green

P.S. Here's an edifying example of just how much gas sensible driving can save: I recently drove a 2006 Toyota Corolla on a 210-mile freeway trip. (Yes, even Mr. Green occasionally abandons his principles and crawls behind the wheel, hoping to avoid detection by an overwrought disciple.) I set the cruise control and the overdrive, kept my speed at 55, and got 42 miles per gallon--just over the car's official highway rating of 41 mpg.

If I hadn't driven at this moderate rate and used the technology at my disposal, the mileage could have dipped as much as 33 percent, to around 30 mpg. So before you complain that your car isn't living up to its official mpg rating, check your driving habits and your vehicle's condition.

Much Ado About Cannabis

Hey Mr. Green,
I enjoyed your column in the September/October issue of Sierra, but I have a question about your comments on industrial hemp. You refer to H.R. 3037, the Industrial Hemp Farming Act of 2005, but when I tried to research it, the last information I could find was that it was referred to the House Judiciary Committee. Did the bill die there? --Rebecca in Kingston, Rhode Island

Hey Rebecca,
Alas, the bill is all but dead in the Judiciary Committee, as its members haven't taken it up and are extremely unlikely to do so in the waning days of this largely disgraceful Congress. It will probably be reintroduced next year, though it's not clear who the sponsor will be. (Representative Ron Paul [R-Tex.] sponsored H.R. 3037.)

Hemp backers had pinned hopes on a legalization bill in California, which passed by a big margin in the state assembly, thanks to the type of laudable bipartisan effort made largely impossible by right-wingers in the aforementioned Congress. The California bill even garnered support from the usually conservative state Farm Bureau since hemp could generate considerable revenue. Unfortunately, the bill was terminated by Governor Arnold Schwarzenegger (R), who vetoed it in October.

California's proposal was crucially different from legalization laws passed in Hawaii, Kentucky, and North Dakota. Those laws are written in such a way that a farmer would have to obtain a permit to grow industrial hemp from the U.S. Drug Enforcement Administration, which refuses to grant such permits. The California bill, however, included a clause stating that a permit was not necessary because industrial hemp--which is not a drug--falls outside the scope of the DEA's authority.

If the law had passed and the DEA refused to permit hemp-growing in the state, California would have had grounds to challenge that ruling. If the state had won its case, the federal obstacles to the ancient agricultural practice of growing hemp would have been removed.

Given his own revelations that he darn well did inhale, and frequently, you would think that Schwarzenegger might understand the difference between industrial and psychoactive cannabis. Well, actually, it seems that he does, as evidenced by his preposterous--nay, oxymoronic--excuse for the veto: "I am very concerned that this bill would give legitimate growers a false sense of security and a belief that production of 'industrial hemp' is somehow a legal activity under federal law." Does he really think farmers are so dumb that they'd go ahead and plant the industrial hemp before the feds officially permitted it?

The distinction between the two types of hemp was perhaps best expressed by Ken Junkert, a spokesperson for the North Dakota Department of Agriculture: "You'd have to smoke a [hemp] joint the size of a telephone pole in order to get a headache," he said. You can find out more about hemp issues at
Mr. Green

P.S. In related news, California authorities conducting raids on marijuana growers in state parks have discovered that the illegal agriculture was doing considerable environmental damage. This may increase pressure for legalization of psychoactive cannabis as well, since many folks would rather see it grown legally on farmland than illegally in our parks.

Views expressed by readers may not reflect those of Mr. Green or Sierra magazine. Reader suggestions have not been researched or tested.

Read more advice from Mr. Green, including his Web-only mailbag, and submit your own environmental questions at

Mr. Green illustration by Melinda Beck; used with permission.

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