What about China?

Qu: Would it be possible to put waste, i.e. bio-degradable rubbish and sewage into an air-tight container, let it produce methane gas, siphon it off to cook with and power gas-fired central heating, filter off the water, and be left with compost to put on gardens?

Yes – very possible, in fact it’s already being done. It’s called Anaerobic Digestion and the process is widely used to treat wastewater sludges and organic wastes. Anaerobic digestion can reduce the emission of harmful landfill gases into the atmosphere and is a renewable energy source because the process produces a methane and carbon dioxide rich biogas suitable for energy production. Also, as the question suggests, the nutrient-rich solids left after digestion can be used as fertiliser.

So why isn’t this process used everywhere? Anaerobic digesters require a high level of technical expertise to maintain as careful control of the digestion temperature, pH, quality of input and loading rates is crucial. Because of these complexities, despite being recognised by United Nations Development Programme as one of the most useful decentralised sources of energy supply and being less expensive to run than large powerplants, anaerobic digesters are not widely used in industry. (source)

Anaerobic Bioreactors, a type of landfill, can also transform decomposing material into an energy source. By removing oxygen and pumping lechtate (water which has collected waste products from the decomposing matter) and other liquids around the bioreactor the waste produces methane, which can be collected and used instead of fossil fuels. (source)

Perhaps the most exciting and accessible use of the anaerobic production of methane from plant waste is the ‘pyrolysis unit’ – invented for domestic use in India by Ravi Kumar. A family collects waste plants, dries then and puts them into the unit’s circular casing. This casing is sealed to stop oxygen combining with CO2. A small fire is started in the central void; this heats up the plants and causes them to emit gases through small holes in the casing. The gases ignite and burn for long enough to cook dinner (about an hour). Then, brilliantly, the remaining charcoal can be raked out and used as fertiliser – what’s more the soil’s subsequent ability to lock in carbon dioxide also increases. (James Bruges – What About China?- p19)

Hope that helps, 

Bethan

Qu: Having read your answer on the effect of patio heaters (last bastion of the smoker) on global warming I wondered what the effect of the 6 billion cigarettes smoked annually around the world has on the global environment?

Oh dear, this answer sure ‘ain’t pretty. Now I’m really going to have to disown all my still-fag-smoking now ex-mates. 

Let the anti-ciggie tirade begin! Starting at the end and working backwards seems appropriate as cigarettes are most obviously harmful to the environment when discarded, marring the view as they lie scattered beneath the fore mentioned patio heaters. 

Sadly, cigarette butts are most often than not thrown to the floor and left as litter.  It is estimated that over 4.5 trillion cigarette butts are irresponsibly disposed of annually, making them the most littered item in the world. 

There seems to be a general consensus (ask any smoker) that cigarettes are bio-degradable over a 25 year period– however this figure is debatable and some experts doubt that the filters will ever degrade. Even as they break down cigarettes are harmful as they release the 4,000 chemicals that they contain, contaminating the soil or rivers, lakes and ocean that they are washed into. Wildlife is also affected as these toxins enter the food chain and many creatures fatally consume the indigestible fibers. Cigarette packaging is often littered as well; in the UK alone, each day, 122 tonnes of cigarette related debris is thrown out.

As they are smoked they are an environmental nuisance, as 90% of their smoke gets into the atmosphere, adding to air pollution (remember the days that you couldn’t even see to the bar when you walked into your local) and having a negative impact on the health of anyone nearby. 

If you think all that is bad then wait till you hear about the environmental impact of cigarettes. It is estimated that up to 200 000 hectares, usually in the developing world, are cleared to make room for tobacco farming every year. The sensitive tobacco plants are then treated with a nasty cocktail of fertilizers, pesticides and herbicides to protect them from insects and disease. Tobacco farms are often by villages and, when the chemicals inevitably leak into the soil, they begin to poison the waterways, ecological systems, crops, and livestock in the surrounding communities.  Tobacco uses more nutrients than several other crops, and this quickly degrades the surrounding soil.  It is also believed that the toxic chemicals may indirectly cause the development of pesticide-resistant mosquitoes and flies.      

Living by a tobacco farm is no fun then, but this gets a whole lot worse if you’re unlucky enough to be one of the workers harvesting the plants. When the wet leaves are picked nicotine can be absorbed through the skin resulting in nicotine poisoning.  This ‘green tobacco sickness’ causes dizziness, nausea, vomiting and breathing difficulties and affects 41% of workers every season. 

On top of the land clearance for tobacco planting we must also take into account the trees that are felled to process the leaves and to produce the wrapping and packaging for cigarettes. Nearly one hectare of forest is needed to dry every hectare of tobacco meaning that over 600 million trees are destroyed annually for this purpose. On top of that six kilometers of paper is used per hour by the machines that roll and package cigarettes! 

And then there is tobacco’s contribution to world hunger. According to Dr Judith MacKay, Director of the Asian Consultancy on Tobacco Control in Hong Kong, tobacco’s “minor” use of land denies 10 to 20 million people of food. 

Anyone fancy popping out for a smoke? Didn’t think so!

Bethan

Thanks to these links for the above information.

http://www.smokefreecalgary.com/bins/content_page.asp?cid=3-119&lang=1 
http://www.litterbutt.com/
http://?www.aadac.com/87_447.asp?
http://tobaccofreekids.org/campaign/global/pdf/ag2.pdf
http://?www.hpb.gov.sg/hpb/default.asp?pg_id=865&aid=105
http://?www.cigarettelitter.org
http://www.ci.berkeley.ca.us/publichealth/tobacco/environ.html?
http://www.ash.org.uk/html/international/html/environment.html?http://www.longwood.edu/cleanva/cigarettelitterhome.html

Qu: What’s your stance on energy saving light bulbs? I’ve heard several reports that they contain mercury and can be dangerous.

The media had a field day at the end of last year with some serious scaremongering regarding the dangers of energy-saving bulbs (CFL’s).

It all began when The Daily Mail picked up on a report by the Environment agency calling for a public awareness campaign to explain that the packaging of energy-efficient lighting contains small amounts of potentially toxic mercury and should therefore be disposed of with care.

The Mail ran a typically hysterical piece headlined “An energy saving bulb has gone - evacuate the room now!”

The general thrust of the article being, ‘energy-saving light bulbs are so dangerous that everyone must leave the room for at least 15 minutes if one falls to the floor and breaks.’

This is, of course, an exaggeration of the facts. Toxicologist Dr. David Ray, from the University of Nottingham, told the BBC that 6-8mg of mercury is present in a typical low-energy bulb. A pretty small amount considering thermometers, which we happily stick in our mouths, contain about 3 grams of the stuff.

Dr. Ray concludes that a smashed bulb causes little danger - but warns that this increases proportionately to consistent exposure and greater numbers of smashed bulbs. DEFRA also played down the threat to health, saying; ‘No amount of mercury is good for you, but the very small amount contained in a single modern CFL is unlikely to cause any harm, even if the lamp should be broken,’

(It’s also worth noting that strip lighting has always contained mercury - yet no-one seems to be complaining about that!)

The Mail went on to finger energy-saving bulbs as a potential source of cancer following a report by British Association of Dermatologists (BAD).

In this next distortion of the facts they claim that the ‘new’ lights (they’ve actually been around for over 30 years) “can trigger migraines, as well as dizziness, loss of focus and discomfort.” However the article goes on to say that these symptoms would only affect people already suffering from certain conditions (like epilepsy and photosensitivity). Dr Colin Holden from B.A.D. explains that people suffering from photosensitive skin conditions should be allowed to continue to use daylight (tungsten) bulbs to prevent “photosensitive eruptions ranging from disabling eczema-like reactions, to light sensitivities that can lead to skin cancer.”

Fine, those with a medical condition would obviously be prescribed the old bulbs, but that shouldn’t stop everyone else switching to CFL’s.

The real concern, the one that started this debate in the first place, is the environmental impact of disposing of the energy-saving bulbs. The Environment Agency’s call for a public information campaign acknowledges a need for greater awareness before tungsten bulbs are completely phased out. Careful disposal of the energy-saving bulbs will prevent the mercury content being released into the atmosphere. Thankfully more and more places now provide the facilities for you to drop off your used bulbs to be disposed of safely, including council refuse tips and some bulb retailers (Ikea, DIY stores etc.) and this service will become more widespread as CLF bulbs become more popular.

Besides, it’s reported that, even if everyone just threw their CFL light bulbs into the main rubbish to go to landfill, the amount of mercury entering the environment would still be less than that which currently enters the environment as a result of the production of the electricity needed to power all the traditional lightbulbs. Besides, CFL bulbs last far longer than traditional ones so there will be far less of them to throw away (source). So, no excuses, off you pop to the shops to buy your new bulbs…

Bethan