Re: [GreenYes] Single Stream Recycling Pros and CONS

["Wayne Turner" <WAYNET@cityofws.org>]

Ann Schnieder wrote:

"Apparently my home town, the City of Mountain View is considering
converting our bi-weekly source separated curbside recycling program to a
single stream program under a 10 year "evergreen" contract.  The Mayor
has asked me for information on this system especially the Cons as the
garbage company has not been providing much info on that side.

....

So if any of you have some studies you can point me to, I would
appreciate it."

Hi Ann,

No studies Ann, but here is a brief blurb about my personal experience.

I live in a City (and used to work there as the waste reduction manager) that has a single-stream, automated recycling program.  The primary advantage of this type of program is its convenience for the residents.  The automated approach is also convenient for the solid waste department and very cost effective for the collection side.  We use large, 96 gallon recycling carts (and a companion 96 gallon cart for garbage).  Residents are allowed to completely co-mingle their recyclables in the cart.  

During collection, there is a lot of glass breakage when it falls from the cart into the truck hopper.  There is additional glass breakage when the truck is unloaded at the MRF and during sorting.  My educated guess is that we only recovered about 33%-50% of the glass we collected.  If you have a market for mixed, broken glass, this might not be a problem.  It doesn't address the problem of paper contamination by broken glass, though.  Overall, I think the quality of the commodities from our singe-stream program were significantly less than commodities from source-separate programs.  This didn't necessarily translate into lower prices for the commodities, though, since our MRF operator had floor prices negotiated for all its commodities from all its MRFs accross the country.  The abrasive broken glass did take a toll on the MRF equipment.  I never received any comments from the MRF operator about worker injuries due to the broken glass.  They wore protective gloves and didn't attempt to pick the broken glass - hence the low recovery rate.

The most troublesome part of the program was that the large, lidded cart allowed system abuses that could create health problems.  With a 96 gallon cart, you can use your imagination to think what people could put in them that shouldn't be in there.  And it happened, periodically!  Again, the automated approach is what created this dilemma.  The drivers weren't inspectors as is the case in most source-separated programs.  Although, we did have a team of 5 solid waste inspectors that performed routine, random inspections of the recycling carts, with 7,500 set-outs per day, they were hopelessly outnumbered.  So, they concentrated their efforts in areas of the city where they knew contamination would most likely be.  Once the cart was emptied into the truck, whatever was in the cart was mixed with the rest of the load.  Initially gross contaminants were not uncommon, but through education and service denial and ultimately, susepension from participation in the program, this was ameliorated.  Still, there is a high price in terms of quality that will be paid when you go with a single-stream *automated* recycling collection system.  If your MRF is highly automated (to keep processing costs low), can deal with occasional gross contaminants (e.g. yard waste, food waste, etc.), and has markets for mixed, broken glass, there may not be significant downsides to this system.  I know there are some on this list-serve who decry single-stream systems as the bane of recycling, but it appears that the approach continues to gain popularity, as evidenced by your email.  I''m sure you'll receive other viewpoints on your inquiry.

Regardless of what kind of system you end up with in Moutain View, best of luck.






B. Wayne Turner
City of Winston-Salem
Utilities Division
phone: (336) 727 8418
email: waynet@cityofws.org

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