More Clean Energy From Plastic Trash

This blog entry is a little technical but interesting in that it demonstrates that our waste and particularly our plastic waste have the potential to serve a useful purpose, that is if all plastic was biodegradable.
ENSO Bottles supports the development of bioreactor landfills. All landfills produce gases that can be captured; however, a bioreactor landfill is more efficient means of producing and capturing biogases produced during the biodegradation process. Here’s an interesting tidbit about how the ENSO plastic bottle can be used to produce energy. ENSO Bottles biodegrades in a microbial environment and when it does it produces biogases, water, and humus.
How much energy can the off gassed methane from an ENSO bottle generate?

To calculate how much energy can be created from ENSO bottles take the weight of the ENSO bottle multiply it by % carbon, multiply by 1.33 (molecular weight of CH4 16 / molecular weight of carbon 12 – this converts the carbon to methane), then multiply by 22.4 (L/g – ideal gas law).

(Bottle wt * bottle carbon %) * (methane mass 16 / carbon mass 12) * 22.4 L/g = vol. methane per bottle

(19.2 gram * 62.5%) * (1.33) * 22.4 = vol. of methane per bottle

(12) * (1.33) * 22.4 = 357.50 L * (1 m3/100 L) = .3575 m3

Once we know the volume of methane per bottle we need to convert that into how much energy can be created per volume of methane. The Thermal energy content of methane is approximately 26.73 – 32.7 kj/m3 therefore about (26.73 + 32.7) / 2 = 29.715 kJ/m3

.3575 m3 * 29.715 kJ/m3 = 10.623 kJ

1kJ/second = 1kW and considering a 100W light bulb:

10.623 kJ = 10.623 kW seconds * (1000 W/1 kW) * (1 hr/3600 s) = 2.95 W hr

To light a 100W light bulb for 1 hour would require 33.88 ENSO bottles:

100 W * (1/2.95 W hr) = 33.88

Let’s take a look at the real number of plastic bottles ending up in landfills. In 2006, approximately 31 billion single serve water bottles were not recycled and ended up in landfills. These bottles if they were biodegradable could result in approximately 1 million hours of light for a 100W light bulb.

31,000,000,000 bottles * (1 hr/33.88 bottles) = 914,759 hrs

ENSO Bottles supports recycling plastic bottles; however, with less then 30% being recycled a realistic approach toward solving plastic pollution is to use plastic that biodegrade. Plastics that are able to biodegrade in a landfill environment have the potential to produce clean energy.