Unrecyclable recyclables issues
Exploratory Data analysis on the comparison of single-stream recycling and multi-stream recycling
We like recycling. We all think that the things we recycled could be reused for making something useful. However, some of the recyclables, actually, directly go to the landfill because of too contaminated. The article The Era Of Easy Recycling May Be Coming To An End discusses “more recyclables means less recycling.”
Americans love convenient recycling, but convenient recycling increasingly does not love us.
Single-stream recycling is a system of dumping all the recyclables into one bin. This system encourages more and more people participant in recycling due to its convenience. But as more and more material put forward for recycling, the cost dealing with unrecyclable recyclables increases.
On average, about 25 percent of the stuff we try to recycle is too contaminated to go anywhere but the landfill, according to the National Waste and Recycling Association, a trade group. Just a decade ago, the contamination rate was closer to 7 percent, according to the association.
Most recycling programs in the United States are now single stream. It causes a problem of high loss of recycled due to contaminated. In the article, it includes a comparison of different recycling stream types.
According to the table above, we can see multi-stream has a higher percentage of actually recycled rate than single-stream. Also, multi-stream has the lowest percentage of loss due to contamination among the four types of the recycling stream. However, the collection rate of multi-stream is the lowest. In order to encourage people to recycle, the local government chooses single-stream over multi-stream. If people’s engagement in multi-stream recycling is low, even the system could perform well on converting recyclables to other materials, the total amount is still low. Due to this reason, the government switch to using single-stream recycling for high recycling collection. But then, the new issue comes out — — more and more unrecyclable recyclables.
Anticipated data to explore this relationship would be a dataset included recycling materials recovery rate and residential recycling rate. Compared these rates between a city using single-stream recycling and the one using multi-stream recycling. Ideal analysis results will give us an answer to whether the local government cares more about actual recycling rate or people’s engagement in recycling.
I performed an EDA using Jupyter notebook. The two datasets I found are Recycling Diversion and Capture Rate in New York and Solid Waste Generation & Recycling in Washington State.
- New York — Multi-stream
- Washington — Single-stream
After the data cleaning process, these two datasets all remain data from 2005 to 2014.
As we can see the plot below, for every year, multi-stream recycling had a higher diversion rate than the single stream. While the single stream’s recovery rate was inconsistent, multi stream’s recovery rate was in an increasing trend.
However, single-stream recycling had a much higher capture rate than multi-stream recycling every year from 2005 to 2014.
This huge difference in recycling capture rate shows why most of the cities choose a single-stream program than a multi-stream program.
Although New York still uses multi-stream recycling, an article from Waste 360 saying New York will switch to single-stream recycling by 2020 to speed up the reduction of greenhouse gases. Also, the move is meant to increase participation by making the process simpler for residents.
Even though we know that multi-stream recycling could maximize the actual recycling rate, local government will still choose to use a single stream program. It’s hard to tell whether the huge loss of recycled due to contaminated because of single-stream recycling will turn all recycling stream back to multi-stream one day.
