Plastic Micro-factories in Agbogbloshie

Posted on by ivyasuo
Pellet made by extrusion process
Plastic pellets made by extrusion process

Plastic waste in Ghana has become a major social and ecological problem, due to the adverse effects of plastic pollution on both human health and the environment. Especially during periods of flooding, plastic waste chokes the drainage systems of most Ghanaian cities.  The need for initiatives to improve sanitation in our community is of great importance. Of the many local waste management companies, only few practice segregation and recycling of waste — and not yet at scale. In the area of plastics recycling, Blowplast recycling is one of the formal organizations which recycles water sachet and black bags in large volumes. What a lot of people do not realize is that plastics recycling in Agbogbloshie is a major activity within the informal sector recycling industry.

Because we are current developing a plastics micro-factory as part of the AMP toolset (one of first prototypes is a mini-kiln for moulding plastic tiles), we continue to work with Agbogbloshie plastics recyclers in order to better understand how the process works now and how it can be improved.

One of the more advanced industrial setups we have come across is located on Abosey Okai Road. Stages in the process flow include sorting, shredding and pelletizing. This micro-factory engages more then 20 youths in Agbogbloshie in full-time employment! The sorted plastics are ground using a milling machine (see picture below) which is connected to a water bath. Shredded plastics are then collected and dried. Finally, the shredded high-density polyethylene (HDPE) are pelletized using an extrusion machine. These pellets — made out of plastic waste from all over Accra — are then sold as feedstock to formal industries both in Ghana and globally that have the capability to produce plastics films.

The existing model of plastics micro-factories in Agbogbloshie deserves support and attention. In effect they perform a massive public service: cleaning up the city of Accra, by making profits from our plastic waste.

Grinding machine in Agbogbloshie
Grinding machine in Agbogbloshie

Mini-Kiln first prototype

Posted on by Emmanuel K. Ofori-Sarpong

Making a mobile oven, or mini-kiln; for melting plastics originally but whatever you need to bake. Pick or make the right caster wheels for the sort of mobility mini-kiln usage requires.

metal casters

mini-kiln with flexible tube to LPG cylinder attached.

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Plastics constitute a significant portion of the Agbogbloshie waste stream, moving through stages of collection, sorting (by type and colour), cleaning, shredding and even in some cases molding into pellets. (See Plastics blog post). With at least 7 micro-factories by our count, Agbogbloshie is a key part of the plastic recycling industry in Ghana, and integrally interconnected with both local and global production cycles. To date, the failure of Agbogbloshie’s industrial ecosystem to add value to plastic material recycled on-site is a lost opportunity for local manufacturing.

Building on our experiments with plastic during AMPQAMP and drawing on the knowledge and expertise of oven fabricators based on the ground in Agbogbloshie, we are now co-designing and prototyping a mini-kiln. This week, William Mensah completed fabrication of the first  prototype in Accra Timber Market,adjacent to Agbogbloshie. The mini-kiln fits the standard module of the AMP spacecraft and is one of the first tools from the AMP tool-set developed to plug into the community workshop.

mini-kiln in accra timber market, fiber insulation exposed before top sheet fixed in place.

The prototype, is composed essentially of a frame of angle bars,  inner and outer layers of sheet metal with a layer of what is locally called “fibre” (PUR foam insulation sourced from air-conditioner dismantling). We didn’t finish until evening, but couldn’t wait to test. Hence using shredded plastics from Agbogbloshie, we  made new recycled plastic tiles, heating the the plastics to their melting point, and allowing them to cool. We intend to carry out carry more of such low-high tech plastic experiments soon in our spacecraft. Stay tuned for more and be sure to share with us, your innovative ideas regarding plastic recycling.

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Plastic tiles made by using the mini-kiln
Plastic tiles made by using the mini-kiln (From the left: HDPE, PP and PET recycled plastics)

Notes:
+Need to add chimney, temperature gauge, and calibrated gas control.
+Cost compare with 2-module wide unit, cylindrical drum cast concrete or clay insulated.
+Link with rotational plastics moulding machine:feedback-enabled temperature controls.

#ampqamp14 – Weeek 1

Posted on by ivyasuo

First weeek =) of#ampqamp14 started at Hub Accra by a discussion of AMP’s objectives for the three coming weeeks: to co-design and build with AMP makers (comprising of STEAM students and graduates and eventually e-waste workers) a module of the spacecraft–AMP’s  makerspace–and share its progress with the community in Agbogbloshie.

Participants started discussing the design of the spacecraft, its frame and interior frame comprising of an octet truss system, prefab panels, soft and roof systems. We then developed a critical path for each system so to know what to do at each step of the way until we build the spacecraft. The brainstorming sessions were very intensive, with some of the participants sketching/drawing the various concepts related to the spacecraft.

 

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Participants designing the critical path
Participants designing the critical path

By the second day we enthusiastically produced fully developed critical paths,  identified and quantified in terms of duration and dependency of the various tasks

Critical path for AMPQAMP
Critical path for AMPQAMP

We also prepared for the first workshop ahead, the plastic workshop to be carried out at the Rex Cinema in collaboration with Brad Marley and Efya  from the POLY Bank GH organization. In preparation for the workshop, we conducted background research on the physical properties, melting methods and stewing methods. We sourced the plastic–shredded-PET (polyethylene therephatlate) old plastic bottles and stewed shredded-PP (polypropylene)–and a number of molds from Agbogbloshie. This was also a good occasion to share our process with the Agbogbloshie community. This is a picture of the tools we brought to the Rex Cinema to conduct our experiments.

Tools bought from Agbogbloshie for the experiment
Tools bought from Agbogbloshie for the experiment

The Rex is an open-air cinema, a wonderful space to experiment within. There, young Ghana makers were busy melting, stewing and molding different types of plastics and exploring the production of architectural parts, panels, brick or tiles, made of recycled plastic. Sam and Idrissou, Agbogbloshie community agents, helped with burning the charcoal.. They were far more skilled than us!

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Below are some of the observations from the experiment:

  • We observed that the PET melting process was very slow and began really late, also at temperatures slightly higher than 260◦c, which is the theoretical melting point value. PET began to char and thus underwent incomplete carbonation and changing color from a transparent blue color a marble brown colored plastic. PP however, started melting at a lower temperature and rather melted over a larger temperature range and also produced a smooth finish.

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    Marble brown colored tile made from PET
  • We may have over heated the PET plastics, which led to the formation of a brittle-porous tile.
  • Contributing factors to such brittleness of the plastic panel are associated to the cooling rate and media and this caused cracks.

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    Cracked tile made from PET
  • Also, the temperature of the charcoal flame could not be controlled and hence over heating ensued.
  • It was also observed that stewing of PET did not work. This is probably due to the fact that it has a high melting temperature and the oil doing not facilitate that phenomenon.
  • PP plastics however work well with stewing in oil. From the experiment, we formed a very strong mold which can be used for wall panels, table tops and many others.
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Brick made by stewing PP plastics

 

Find here the Lab report.

We were honored to host Prof. Kwadjo Osseo-Asare (AMP co-PI) and Dr. Victor Oteng-Atiemo (retired from MD of DOW chemical Ghana) who gave us advices on how to proceed and continue our experiments.

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Here is the link to Flickr photo set.

The Sound of Plastic

Posted on by pervasiveyaz

There is more than e-waste processing happening in the open-air recycling factory: plastic processing represents a significant portion of Agbogbloshie’s ecosystem and economy.

Woman in the plastics business
Woman in the plastics business

The plastic processing chain involves various actors (male and female — contrary to e-waste processing which does not employ female workers) and machines:

  • Collectors get plastic waste from all around the city and temporarily store them onsite. Dismantlers scrap plastic out of e-waste or other items.
  • Men and women sort out plastics based on empirical and heuristic approaches: they separate plastics according to their thickness, malleability (thermoplastics are malleable and can be recycled, while thermoset plastics are not), and by the sound plastics make when workers bang on them with a screwdriver!
  • In our interaction, workers in Agbogbloshie did not know about the resin identification code system. However, as observed many locally-made plastics lacked labels, as well as scrap pieces of plastic detached from primary parts in which the label is inset. Thus, if the processing is carried out in a hasty and crude manner, then having resin identification codes may not be overly helpful.

As we learned by watching the documentary film The Electronic Tragedy by Dannoritzer Cosima, in other parts of the globe where informal plastic processing also occurs, heuristic approaches include burning plastics with a lighter and smelling the burnt material – each type of plastic has a different burning temperature. This strategy is more dangerous for the workers’ health than local methods of differentiating between types based on the sound of plastic.

Plastics sorted by color
Plastics sorted by color
  • In Agbogbloshie, it is common knowledge that television cases (made of non-recyclable thermoset plastics) cannot be sold for recycling. And this is also the reason why the item is often used for storage or as a stool. The local workers separate plastics into three main categories (while there are seven identified categories of plastics. PET (bottles) and PVC (pipes) are in addition): “rubber” (e.g. polypropylene, PP), “gallon” (e.g. high density polyethylene, HDPE), and “plastic” (not recyclable). In all, they process Polypropylene PP, High Density Polyethylene HDPE, Low Density Polyethylene LDPE, Polyethylene Theraphalate PET, Polyvinyl Chloride (PVC), and other types such as PP-MD20, and PP-TD30.
  • Women remove labels and caps of PET containers (water bottles for example; water bottle c­­­aps are made of another type of plastic). Workers sort recyclable plastics by colors before (loud) shredding using locally fabricated shredding machines. They then sieve the shredded plastics before washing it. The plastic is now ready to be sold to industries – local and global!

Prices vary according to the type of plastic and depends on the market. For our plastic experiments, we purchased the Kg of shredded PET for 3 Cedis and the Kg of PP for 2 Cedis. The workers specialized in plastic processing were rather excited about the business opportunity afforded by our plastic experiments (bricks and tiles made with PP and PET) and we look forward to this knowledge transfer.

Find more pictures on Flickr.