I had the chance to get an inside look at the Tuas Incineration Plant last Thursday! It was fascinating! Here’s a sneak peak before I post more about it later:
Anyway! On to plastics. I’m definitely not an authority on this, but I’ve done a little secondary research around the web to find out more about plastic waste for the purpose of this project. Here’s a little of what I’ve found out.
What happens to Singapore’s plastic waste*?
*Noting that waste is not waste unless it is wasted! We can give plastic a new lease of life by recycling it :).
According to the Ministry of the Environment and Water Resources’ Key Environmental Statistics 2012, 730,000 tonnes of plastic waste was generated in 2010, with a recycling rate of just 11% (only 2% up from 2008). Plastic that is not recovered for recycling gets incinerated and landfilled.
How does plastic waste get recycled?
Paraphrasing Zero Waste SG’s great guide to recycling plastic,
Plastic waste can be divided into pre-consumer and post-consumer plastic waste.
Pre-consumer: Plastic scraps generated by companies during the manufacturing of products. These plastics are usually easier to recycle as they are clean and homogeneous.
Post-consumer: Generated by consumers after use. They are more difficult to collect, easily contaminated with food, and not homogeneous.
Whether pre- or post-consumer, once collected, plastic waste is separated into seven categories developed by the US Society of the Plastics Industry (SPI):
1. PET (Polyethylene terephthalate) – Used for water bottles, soft drink and cooking oil bottles, and meal trays.
2. HDPE (High density polyethylene) – Used for milk and detergent bottles.
3. PVC (Polyvinyl chloride) – Used for plastic pipes, food trays, shrink wrap, and bottles.
4. LDPE (Low density polyethylene) – Used for plastic bags and bin liners.
5. PP (Polypropylene) – Used for bottle caps, margarine tubs, and meal trays.
6. PS (Polystyrene) – Used for food containers, egg cartons, vending cups, plastic cutlery, and protective packaging for electronic goods.
7. OTHER – Includes any other plastic that does not fall into the above categories.
After sorting, plastic waste is baled and exported overseas for recycling. There are also plastic recycling companies in Singapore that sort and process plastic waste into small pellets to be used as feedstock for making plastic products.
Why should we reduce and recycle our plastic waste?
1. It is estimated that 4% of the world’s annual oil production is used as feedstock for plastics production.
2. It is estimated that an additional 3-4% of the world’s annual oil production is used for the manufacturing of plastics.
3. When incinerated, plastics release CO2 and potentially toxic gases such as dioxins.
4. Plastics are non-biodegradable and take hundreds of years to break down. When they are landfilled, they take up valuable landfill space that Singapore just doesn’t have.
What are bio-plastics?
Bio-plastics are an alternative to conventional plastics, derived from renewable biomass sources, such as agricultural by-products and corn starch.
It is argued that the production and use of bio-plastics are more sustainable activities than the production and use of conventional plastics because bio-plastics use less petrol-based feedstock and emit less CO2 and no/fewer toxic gases when incinerated.
It’s important to ask how much non-renewable energy and water goes into powering farm machinery, irrigating farms, producing pesticides and fertilizers, and transporting and processing crops. Only then can a more accurate comparison between conventional plastics and bio-plastics be done. (I’m personally a bigger fan of the use of agricultural by-products because it seems to avoid these issues.)
There are different types of bio-plastics, each with their own pros and cons. As I mentioned, some of them make use of agricultural by-products, whilst others use crops grown for the production of bio-plastics. Some are made purely from biomass sources (polylactic acid, PLA), whilst others are a mixture of biomass and conventional plastic (such as polypropylene, PP). Certain bio-plastics are biodegradable and compostable, others are only biodegradable, and some are neither. The recycling of bio-plastics is in its infancy – it can only really take off when the necessary recycling infrastructure is put in place. In Singapore, bio-plastics cannot yet be recycled.
A good look into all these factors is needed before we categorically declare all bio-plastics as the Next Green Thing. We need to look at life cycle assessments that take into account comprehensive cradle-to-grave energy/water/land usage, greenhouse gas emissions, and toxic waste emissions. An example is this University of California, Santa Barbara study that assesses the life cycles of plastic yogurt containers made of polystyrene (PS) versus plastic yogurt containers made of PLA. Its major finding is that the PLA containers release 48% less carbon than PS ones, providing the basis for Stonyfield Farm’s decision to switch over to PLA yogurt containers.
So what’s the deal with biodegradability and compostability?
First, a distinction should be made between the two: biodegradability simply refers to the ability to be consumed by microorganisms and decomposed back down into compounds found in nature, whilst compostability refers to the ability to biodegrade quickly in a composting pile. A composting facility optimizes surrounding conditions, i.e. humidity, temperature and lighting, so that waste can be efficiently converted into humus, which can then be used as a nutrient-rich fertilizer for farming.
Singapore incinerates all waste that is not recycled, and landfills the remaining ashes. There are no large-scale composting facilities in Singapore* (since the recent closing down of IUT Global), though some great groups have taken it upon themselves to start their own compost piles (big applause!). As such, I’ve been asked a number of times if biodegradable and compostable food packaging products are even relevant here.
I believe they are, but not because of those properties in particular. Olive Green’s cornware, for example, may be 100% biodegradable, but it is because it uses less petrol-based feedstock (it’s 90% biomass-based, and 10% plastic) and releases less CO2 and no toxic gases when incinerated, that I consider it a promising alternative to conventional pure plastic.
*At the Tuas Incineration Plant, I asked the operations engineer leading the tour whether another food waste-to-energy recycling plant might be in the works for the future. He said there might be plans for one – I certainly hope so! I’ve had the chance to eat apples grown in an orchard that uses the compost collected from my house at Vassar, and I hope to one day do something similar in Singapore :).