The blog formerly known as   Fake Plastic Fish

October 8, 2007

Recycling Part 2 – Lessons from the Davis Street Transfer Center

As I mentioned in my first post on the subject of recycling, “Wait! Are you sure that’s recyclable?” I’d scheduled a trip to the Davis Street Transfer Center today, the place where all of Oakland’s garbage and compost and much of its recycling is taken before moving on to its next use or final resting place. My tour guide today was Rebecca Jewell, Davis Street’s recycling program manager. And our first stop was the brand new $9 million MRF (Materials Recovery Facility) which processes up to 400 tons of recyclables per day for 12 difference Bay Area jurisdictions.

Unfortunately, I was not aware before I came that while Davis Street accepts my household garbage and compost, a different recycling company, California Waste Solutions, picks up and processes the recycling for my area of Oakland. According to Rebecca, it’s a smaller facility and may not be able to handle as many different materials as the Davis Street MRF can. So I’ll try to schedule a tour of that one so I can compare. Nevertheless, touring the Davis Street facility was extremely educational. As you’ll see, I took a lot of photos.

First, all the single-stream recycling is dumped in the entry of the MRF, where it’s then moved onto the sorting machine. Unfortunately, the sorting machine was completely stopped when I entered the MRF and had been for about a half an hour. Why? Plastic bags and other unrecyclable materials jamming the machine!

LESSON 1: Do not put loose plastic bags or any other kind of plastic sheeting in your recycling bin! I said it in my previous post, and it’s worth repeating here. Likewise, no blankets, hoses, ropes or other strapping materials. Think of your vacuum cleaner. You know how it jams up if you suck up a piece of string or cord and then you have to spend a while unwinding it? A sorting machine gets jammed in the same way, only on a much bigger scale. See for yourself:

Here is a list of other materials that can wrap around the machine and cause it to jam: chains, Christmas lights, clothing, copper tubing, cords from electronic devices, extension cords, tarps and other plastic film, metal hangers, sheets, string, wading pools (yep, it’s on the list!), wires. Do not put these items in your recycling bin.

LESSON 2: Certain heavy items will damage the equipment and should not be placed in the recycle bin. A lot of these will be obvious, but I’m pulling them from a list that Rebecca Jewell created based on actual items that people have placed in the bin. They include: bowling balls, bricks, concrete, engine parts, rock, tires, toilet seats, and other building materials.

In addition to heavy items, one of the biggest hazards in the recycling stream, believe it or not, are mini propane tanks. Yes, people try to recycle them. And yes, they explode in the machine and are a hazard for workers. Just inside the entrance to the facility was a whole bin full of tanks that had been pulled from the stream:

Normally, the belt is moving and a team of pre-sorters grabs out anything that might jam the machine before it’s too late. But sometimes there is just too much material and they can’t remove it in time. When that happens, everyone else has to wait while a few people unjam the machine.

Besides items which might clog the machine, the pre-sorters are looking for other non-recyclable items. Anything tied up in a plastic bag will be removed.

LESSON 3: Never put your recyclable items in a plastic bag. Especially if it’s tied shut, that entire bag and it’s contents will be removed and discarded with the garbage. The workers don’t have time to open up the bag and see what’s in it. And they wouldn’t want to anyway. There could be nice cans and bottles inside, but there could just as easily be dog or cat waste.

Even with the machine stopped, I was able to get a good idea of the process. As the materials go over the sorter, blown by large fans, the lighter material, like paper (or fiber, as it’s referred to) is lifted up and goes one way while heavier materials like containers fall down and go another.

As you can imagine, with those fans blowing, shredded paper is a nightmare.

LESSON 4: Unless your recycling company instructs otherwise, do not put shredded paper in your recycling bin. First of all, according to Rebecca Jewell, the fibers of shredded paper are too short to recycle in the first place. So it just ends up blowing around and getting mixed in with the glass. Her feeling is that shredding is over-rated; the workers are way too busy to read any of the masses of paper that come through.

Nevertheless, I did see an unshredded personal check lying on the floor. In fact, I stepped on it. Maybe the workers are too busy, but what about other tourists like me? Well, the good news is that shredded paper can be composted. Here in Oakland, we can put it in our green compost bin. You could also put it in a home bin. And perhaps knowing that shredded paper isn’t recycled will make us more selective of the items we do choose to shred.

Once the materials are initially sorted, a belt passes the cans, bottles, and containers under a huge magnet which pulls out tin and steel cans. The rest of the materials travel along an assembly line of workers who are assigned to select certain types of items and toss them into separate huge bins. On the other side of the MRF, workers separate the paper into bins of newspaper, cardboard, and mixed papers.

LESSON 5: NEVER put needles in your recycling bin. This should be obvious, but apparently, it’s not. The workers wear protective clothing and gloves. Nevertheless, every few months, someone gets stuck.

Once a bin is full, the door opens and all of that one type of material falls onto the belt below, which carries it through another machine where it is compacted and extruded into large square bales. There are bales of newspaper, mixed paper, cardboard, plastic bottles, cans, and other types of plastics. I didn’t actually see what happens to the glass, but I read in my materials afterwards that it’s broken and shipped to Davis Street’s glass-processing partner.

LESSON 6: Bottle caps should be removed or at least loosened. Even with the caps on, the bottles will still be recycled. But a tight cap traps air in the bottle, which makes it harder to compress. It may also trap liquid.

While a maximum 10% contamination rate is allowed, it’s very important for the recycling facility to keep contamination at a minimum in order to receive top dollar for the materials. Here is a list of items that contaminate the waste stream at Davis Street. It’s possible that the rules where you live might be different:

GLASS: Only bottles and jars are recyclable. Other materials such as ceramic, china plates or cups, dishes, mirrors, laboratory glassware, light bulbs, pyrex, porcelain, and window glass have a different melting point and chemical composition and will create weak points in new glass containers.

PAPER: These types of paper should not be included: candy wrappers, carbon paper, charcoal bags (because the dust makes the air unhealthy for workers), food-contaminated paper, hardcover books, napkins, paper plates & cups, paper towels, pizza boxes, shredded paper, tissues, waxed cardboard.

PLASTIC: These types of plastic should not be included: disposable diapers, foam peanuts, unrinsed food-contaminated containers, grocery bags (unless your recycler specifically accepts bags within bags), plastic cups, Styrofoam.

OTHER: Here are more items which cannot be placed into the single-stream recycling bin: Animal waste, batteries of any kind, footwear of any kind, electronic appliances, electronic toys, engine oils, fluorescent tubes and bulbs (they contain mercury), golf balls, green waste, household hazardous waste, liquids, soccer balls, stuffed animals, tennis balls, & wigs. Additionally, even though the city might accept them, Davis Street is not able to recycle Tetra Paks.

Once the materials are baled, they are ready to be sold to recyclers locally and abroad. A lot of metal is sold locally. In fact, on the way in to the facility, I saw quite a few metal recycling companies right on Davis Street. Paper may be sold domestically or abroad. According to Rebecca, the market for recycled paper in this country has been shrinking. #1 and #2 plastics can often be sold domestically, but other types of plastics are generally shipped to China. Here’s a row of containers outside the MRF waiting to be loaded with materials to be sent to China:

LESSON 7: If we want to keep our materials here at home rather than shipping them overseas, we’ve got to support our markets for recycled goods. If we want recycled paper to be made in the U.S., we’ve got to buy it! If we want U.S. companies to make goods from recycled plastics rather than new, we’ve got to purchase those items. A one-way recycling system doesn’t work. If there is no market for the recycled items, no one will produce them.

Rebecca told me another interesting thing about the Chinese market. Unlike other countries, China pays top dollar for recyclable materials and also has very strict standards for what it will accept. If a bale is more than 10% contaminated, China will send the entire container back and bar that company from shipping materials to them again for 90 days. That’s a huge amount of time for a plant like Davis Street that is processing up to 400 tons of materials per day. So this is another reason it’s very, very important for us to make sure we’re recycling the correct materials and that they are clean.

And finally,

LESSON 8: It’s better to recycle grocery bags at the store where you purchased them, if possible, than in your bin even if your city accepts bundled grocery bags in the bin. Different grocery bags are made using different “recipes.” Just because they all have a #2 or #4 on them doesn’t mean they are exactly alike. The plastics will have different melting points. Mixing them together can create a mess, like this block of mixed plastic that Rebecca keeps on display in her office:

Mixed bags are not worth very much. But the bags from a grocery store like Safeway or Albertson’s, for example, are more valuable to recyclers because they tend to be nearly all the same type of bag. Yes, people do bring bags from other stores to the Safeway bin, but for the most part, the Safeway bin contains Safeway bags. And since Safeway knows the “recipe” for those bags, it can let recyclers know exactly what they are getting. If we want our bags, at the end of their useful lives, to actually be recycled, it’s best to return them to the place from which they came.

So, those are some of the things I learned at the Davis Street MRF today. But that wasn’t the end of my tour! I also got to see the garbage dump (aka transfer pit) and I learned about other services that Davis Street offers. I’ll tell you about these things tomorrow.

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Beth Terry
15 years ago

Hi Oz. The bottles arrive at Davis Street however they were dropped by consumers into their curbside bins and then they are compacted at Davis Street before being sold to plastics recyclers.

oz etzioni
15 years ago

are the plastic bottles transported full of air to the recycling facility or they are being squeezed before?

Beth Terry
15 years ago

Hi James. To arrange a tour, you would contact Rebecca Jewell. Her contact info is here:

She’s very nice and seems to love giving tours.


15 years ago

That was a nice read. If i wanted to go on a tour of the place, how do i go about setting it up? Thanks.


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15 years ago

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16 years ago

wow. this post is amazing. i’m definitely going to take your suggestions to heart. i just had a terrible experience with safeway and their plastic bags last night. i forgot my cloth ones- thats the last time!

Rebecca Jewell
16 years ago

RE: What do we do with the propane tanks: we pay the Household Hazardous Waste ( 800-606-6606) folks to come pick them up. That’s what their owners should have done in the first place. HHW staff rock.

Thank you for this post. I sure hope it helps folks decide what to put into their bins.

I can bring others on a tour too. Lemme know.

terrible person
16 years ago

With apologies to Cake:

“I read her piece on the Davis Street station
It is smart, and thorough, and loaded with facts.
She’s tracking her use
She’s cutting her consumption
She’s touring recycling facilities
And picking up trash..
I want a girl with a cool site and NOOOOOOOOOOOOOOOOOOOOOOO
plastic!!! (Da da da da da, da da da da da da…)”

16 years ago

do they send the propane tanks to or what do they do with them, they are explosive.

Gary Barker
16 years ago

This is a wonderful posting on the process of recycling. We’ve been over to the SF Recycling Center and had a tour and it’s an eye-opener as to how the process works.

We’re a sustainable product developer and manufacturing company called GreenHeart Global []. Your pictures are so great we’d love to use them in our description of why we design our products the way we do.

Is it possible to get higer resolutions of the photos and could we use them?


Gary Barker

Deb G
16 years ago

What a great post! One of the things I love about my local recycle/compost pick up is that we can put food soiled paper in our compost. I can pretty much limit my garbage to plastic lids and contributions from the critters….

I also really like your point about having to buy recycled products to close the loop.

16 years ago

Thanks for another super informative post. I never put plastic bags into the recycling since knew they weren’t recyclable here, but I really didn’t know to avoid putting longer strips of plastic into the bin. That’s a really great tip that I never would have thought of. BTW, I think it’s great that you took the initiative and got a tour of the recycling center! It must have been a great experience.

Sarah H
16 years ago

Wow, I learned a lot of things from your post. I try to recycle as much as I can, but it is good to point out that we can’t just recycle haphazardly. Thanks for the post.

Michelle Verges
16 years ago

Beth, I’m joining the chorus here-this was an excellent post! :0)

I like the vacuum-cleaner analogy you used when you talked about plastic bags clogging up the recycling equipment. That’s a great comparison.

And as you mentioned, while plastic bags are a no-no for MRF’s, places like Wal-Mart and Safeway accept plastic bags for recycling. In fact, they make money from recycling plastic bags! I recently learned that each Wal-Mart store in my area made a $10 million profit from their plastic-bag recycling program. So, there’s definitely a market for this product.

It’s “simply” a matter of having access to correct information. I can certainly emphasize with Sunny-I too have heard inconsistent claims on what’s recyclable and what’s not recyclable from folks who work in the business. But your post reminds me that we’ve got to do our homework to uncover reliable information. Thanks again for your hard work!


Radical Garbage Man
16 years ago

Wow! Fun posting and great pictures. You’re very right about tossing things tied up in plastic bags. It’s often garbage that someone carelessly put in their recycling bin. When opening such bags as part of our ongoing monitoring and research, I found a lovely collection of used Q-tips, used Kleenex and used condoms, so let’s have a drumroll:

Rule #9: Don’t gross out your garbage man, man.

16 years ago

Thank you! All those good rules for recycling will be put to use here. The MRF we use is pretty much the same as the one you visited. I have printed your rules for posting (one per week – nobody reads small type) on the 8 recycling toters that I manage here at my condo building. I don’t know if it is possible to upload pictures to your site, Beth, so I uploaded two pix of the recycling notices I placed on bins to the PUPS group on Google!forum/pup-brigade

16 years ago

Great post. I wish we all knew more about the process. In our area, the Mid Valley Recycler’s Association had a document on their website saying you could put waxed cardboard and coffee filters in the compost. When I called my garbage hauler they said that was incorrect. I pointed out the document from the association and my garbage hauler said she would show her boss because the association tells them what they can collect. How bad is it when my garbage hauler doesn’t know what they do? How can we expect people to recycle correctly? I know most people don’t research how to throw “stuff” away like I do. Oh well, you are helping and we can only do the best we can.