We have been gassed – by the approval of a biogas plant. The following list states several reasons why Biogas is harmful to the environment – would you want a factory producing this gas within a couple of miles of your house?? The Government are encouraging the development of this fuel in many rural areas across the country – yet another example of the Government throwing caution to the wind when it comes to protecting the countryside we have left in this country.
Extracts taken from contributors to imechanica.org
Although this seems to be a popular fuel particularly amongst the farming community, and because it is produced from waste products; I am nervous about the lack of regulation particularly when this fuel can produce high levels of Hydrogen Sulphide (sour gas) which is highly toxic. There are farmers that produce biofuels without really exploring the safety issues of the product and indeed the bi-products that they produce. I wonder if they know that most bio fuels in liquid form are methanol rich, and have a tendancy to damage nitrile seals. Also Sour Gas emissions into the atmosphere produce acid rain ( H2S +H2O = H2SO4 after balancing the equation of course). There is an official site but I’m affraid to say it paints a “rosey” picture. Its populartiy is attributable to the use of waste materials however I have less positive views until I see regulations more approprite to the refining of bio fuels. Check out the website it is endorsed by DECC.
The final composition of biogas depends on the source of origin, for example household wastes give 50-60% vol of CH4 while agricultural waste and wastewater treatment plants sludge give CH4 60-75% vol. They also give unwanted compounds like CO2 in a significant amount which ranges from 19 to 38 % and a small quantity of H2O about 6% vol. Agricultural waste give the highest H2S amount that varies from 3000 to 10000 mg/m3, while wastewater treatment sludge gives 1000 to 4000 mg/m3 and household gives the lowest among them, 100 to 900 mg/m3. Household wastes give also a 0 to 5% of N2, aromatic 0 to 200 mg/m3 and organofluorinated or organochlorinated 100-800 mg/m3. Agricultural waste also gives 50 to 100 mg/m3 NH3.
Analyzing further as for the safety concerns, we may check each compound of the final biogas product individually for their potential danger. CH4 is not a toxic gas but it is higly flammable and any leak could cause an explosion, while it is also an asphyxiant gas and inhaling it in great amounts can cause even death. CO2 is also an asphyxiant gas and it can cause from intoxication and poisoning till death according to the amount inhaled, while oxygen presence does not play a role in treatment. Converting the above H2S quantities into ppm we can see that agricultural waste as source gives from 1999 to 6664 ppm, wastewater treatment sludge gives 666.4 to 2666 ppm and household gives 66.6 to 600 ppm. The permissible exposure limit of US Occupational Safety and Health Administration per 8 hours is 10ppm, while in 500ppm and over it causes neural stimulation and rapid breathing till death. It has the characteristic odor of the rotten egg so it can be traced by humans easily, except if its concentration is higher than 100ppm when it sets out of order the olfactory tissue. H2S and H2O are the number one factors of corrosion, a serious issue that cause major problems in the industry. NH3 is toxic for the fishes, while for the humans 66.7 to 133 ppm may cause eyes or lungs irritation. N2 has no significant effects or critical hazards on humans. Toxicity of aromatics varies according to the aromatic compound from not toxic to highly toxic the same as with organofluorinated and organochlorinated compounds.
This blog is for Unicef. For every missed blog post I put £1 in the pot. I missed a blog last night so ‘clink’ goes another £1.
Thanks for reading.