In September I actually followed through with the idea from one of my earlier blogposts about turning off my garage freezer in order to save some money on my energy bill. Around the same time I also started rinsing my dishes with cold water before putting them in the dishwasher and the same goes with washing my hands.  The rest of our energy consumption stayed relatively the same, since this September in Florida was just as hot, if not hotter as the rest of the summer months.

One of the motivators for making this adjustment was the increase in energy bill over the prior couple of months. Usually our electric bill is under tolerable amount of $200, but in July and August of this year, it hit as high as $230. That’s when I decided to go ahead and turn off the old freezer in our hot garage. I am assuming that the freezer was on constantly, since I heard its buzzing sound every time I would pass by it, whether it was day or night. The freezer is quite old, the insulation is worn out, the poor thing had to work nonstop in order to compensate for 100 degree + temperature in our garage. And we had to pay for it!

Another thing I did, as I mentioned earlier, is I started rinsing my dishes and pots with cold water rather than warm, before putting them into the dishwasher. Same goes with washing my hands. Luckily, the “cold” water in Florida is still about 80F warm, so it was a very easy adjustment for me.

Because water has high heat capacity, meaning it takes a lot of energy to heat up, water heater is one of the largest energy consumers out of all of the household appliances. If you can reduce usage of your hot water, you can see the difference in your electric bill. If you live in colder areas, you might be able to see even greater difference in your electric bill. The downside of it is that, you’ll probably have to deal with rinsing your dishes in a 50 or 60-degree water, which may not be as easy to handle.

So when the new bill came, I was pleased. It was around $178! My husband didn’t believe me that turning off the garage freezer would make much difference, so it was nice to confirm by opinion, “See, I told you so!”

Compostable plastic that’s made from plants is not a novelty. The manufacturing process is rather involved. It requires land and fertilizer to grow the plants, mainly corn, then the necessary ingredients need to be extracted from the plant, then additional chemical/biological processes are required that involve energy input. Currently to make a pound of widely used compostable plastic, polylactic acid (PLA) requires 25.5 megajoules of energy, same as burning 118 60-watt lightbulbs for one hour. To make a pound of not yet so popular compostable plastic, polyhydroxyalkanoate (PHA) requires the amount of energy equal to burning 170 60-watt bulbs for an hour.

So the present way of making compostable plastic is still involved and costly, it requires land, fertilizer, plants, additional processing and energy.

But in 2005 researchers at Washington State University developed a method for producing compostable material containing high levels of PHA from paper mill waste products, municipal waste and biodiesel waste. In addition, the fermentation process does not require any special equipment, but the existing wastewater treatment facilities and better yet, no additional energy input.

Apparently this research poses high hopes, since this thermoplastic can be used in a number of conventional applications. Based on the latest information that I was able to find, the research is ongoing. Grants of nearly $450K were pending from National Science Foundation and Idaho State Board of Education for 2008-09.

I can’t wait to know more. Wouldn’t it be awesome to produce compostable plastic from waste without complex equipment and energy input?

Reference: “Wastewater treatment generates PHA plastic.” Industrial Bioprocessing (Nov 25, 2005)

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Biodegradable Plastic – Is It Really?

What is the definition of ‘biodegradable’? Here are some definitions that I found:

• capable of being decomposed by e.g. bacteria
• capable of being reduced to water and carbon dioxide by the action of microorganisms
• capable of being broken down by air, water and bacteria

Up until now, ‘biodegradable’ used to mean to me that if I throw such material into the trash, with time it will sort of dissolve into the environment without harming it. In other words, the nature would accept it back as its own.

Plant based plastic manufactured by NatureWorks is labeled as ‘biodegradable’ and is used mainly as packaging by major companies like Newman’s Own, Wild Oats and Wal-Mart. In simple terms, lactic acid is extracted from corn and then chemically processed to create strong bonding between the molecules, so it becomes polylactic acid or PLA. Currently around 20% of all plastic is PLA and it is used in the form of containers and bags.

Here is the reason why the word ‘biodegradable’ makes me think twice about how such material actually decomposes. In theory PLA is biodegradable, but only in certain conditions. I can’t say it better than what’s already been said by the experts:

“PLA is said to decompose into carbon dioxide and water in a “controlled composting environment” in fewer than 90 days. What’s a controlled composting environment? Not your backyard bin, pit or tumbling barrel. It’s a large facility where compost—essentially, plant scraps being digested by microbes into fertilizer—reaches 140 degrees for ten consecutive days. So, yes, as PLA advocates say, corn plastic is “biodegradable.” But in reality very few consumers have access to the sort of composting facilities that can make that happen. NatureWorks has identified 113 such facilities nationwide—some handle industrial food-processing waste or yard trimmings, others are college or prison operations—but only about a quarter of them accept residential foodscraps collected by municipalities.”              “Corn Plastic to the Rescue” By Elizabeth Royte, Smithsonian magazine, August 2006

These plant-based plastics will break down to basic elements and minerals, usually in an industrial composter through the activity of heat, micro-organisms and enzymes. This decomposition has to be measured by standardized tests and must take place within a specified period of time–which varies according to the ‘disposal’ method. Unfortunately, the industrial composting facilities required are so rare that only a sliver of the biodegradable plastic produced actually makes it to them. Ingeo–a polylactic acid (PLA) bioplastic developed by Nature Works–is one so-called ‘compostable’ plastic that will not break down in home composters. NatureWorks also admits that PLA will not break down if left as litter in the countryside, in soils, seawater or even in landfill. Over a much longer period of time of course it will break down, probably faster than petrol-based plastics. But there are likely PLA fragments happily bobbing around in the world’s oceans already. NatureWorks insists that PLA can be recycled, but no system is yet set up to capture and re-use PLA resin. In appearance PLA can be confused with PET (polyethylene terephthalate) used for plastic bottles and so can actually hamper recycling efforts by contaminating existing recycling streams. In October 2004, a group of recycling advocates called on NatureWorks to stop selling PLA for plastic bottles until key questions were addressed. In January 2005 the company did stop selling ‘additional’ PLA for bottle production but broke that moratorium this past April. NatureWorks has yet to test recyclability of any post-consumer PLA”. Jim Thomas, New Internationalist, September 2008

So basically, if we throw the ‘biodegradable’ bags into the trash, they won’t decompose in the landfill of garbage. At least the vast portion of them.

More facts about PLA

PLA plastic takes one and a half times as much energy to manufacture when compared to it’s counterpart, the polyenthylene or PET plastic. Therefore more fossil fuel is used for production of PLA versus PET with more emissions from the power plant. To make it easily understood, making one pound of PLA equals to the same amount of energy as burning 118 60-watt light bulbs for one hour, and only 78 bulbs for PE.

Huge amounts of corn are required to make PLA,  therefore a lot of land and fertilizer is needed to grow it. Manufacturing of fertilizer involves energy as well, since it is made from separate chemical substances into granules. Granulation process alone requires a lot of energy. These numbers are probably not being accounted for in the above PLA energy consumption number.

Some companies in UK refused to use PLA and went back to PET plastics since they believe that their country’s waste management infrastructure is not set up for handling PLA as it was meant to be handled, so mixing PLA and PE makes it more confusing for the waste management companies and the consumers.

My Contribution

I started to use reusable bags when I go shopping. Wal-Mart and Publix, the two markets that I shop at regularly, offer reusable bags for a buck or less per bag.

In case I don’t have my bags on hand, I request paper bags instead of plastic when available.

I try to buy food that requires plastic containers in bulk. For example, instead of individually wrapped single-serving yogurt containers, I buy one big container.  A lot less plastic is used for the same amount of yogurt. And it’s cheaper too!