Recently a dream came true for me. I had the opportunity to participate in a guided tour through the waste incineration plant in Cologne. That may seem strange. Sometimes I catch myself when I get stuck on documentary programs about recycling methods in the (rare) zapping through the TV channels. Obviously this topic fascinates me.
The BVMW (Federal Association of Medium-Sized Enterprises) invited to a lecture on the topic of generation Y. Host and the venue was the waste recycling company in Cologne, AVG, which offered additionally a guided tour through their waste incinerator. Since I am also very interested in the topic Generation Y, I could kill two birds with one stone.
In a small group, we were led by the spokesman of the AVG through the various sections of the waste incineration plant and the procedures were explained in detail. Initially skeptical, because in previous years there was so much negative about this facility (excessive construction costs, lack of capacity), the mood among the participants changed gradually into fascination.
To clarify: It’s just about waste. Not about recycle materials such as paper, plastics, recycled glass or compostable organic waste.
Precision and cleanliness
What I noticed during the tour: In the plant, each step is carefully considered, it is worked with great precision. And even if that sounds paradoxical: it is squeaky clean! Only in the hall where different wastes are mixed on conveyor belts, there is the typical smell of rubbish, but also not as bad as originally expected.
Amazing for me: I did not know that by using residual waste a really large amount of power is generated. And reassuring for me: resources are won even from the last drop: metal, material for road construction, plaster in good quality. The proportion of what is factually left and actually not recycled, seems negligible to low.
From waste to electricity – the process in detail
The residual waste incinerator in Cologne was put into operation in 1998 and is one of the most modern and best facilities in the world. It processes what has landed in the residual waste after the separate collection of private households, as well as the remains of sorting from mixed building and industrial waste.
Much of the waste is shipped by rail. The railway containers are loaded in two waste transfer stations in the city of Cologne and together have a capacity of approximately 250,000 tons per year. The remaining waste is brought by truck.
A special feature of the Cologne residual waste incinerator is the integrated treatment of the waste in a treatment room. Residues from sorting and residues from the domestic and bulky waste are first distributed to the daily waste bunker on separate chambers. The bulky waste is pre-sorted and crushed. Only the non-recoverable components are processed in the incinerator.
The household waste is sorted in a perforated drum to size and then passes on large conveyor belts so-called magnetic seperators. They remove ferrous scrap. A second ferrous metal deposition as well as an automatic non-ferrous deposition take place after combustion.
Even commercial waste residuals are delivered to the Cologne plant. They have been processed previously in external sorting, so they can be added directly to the domestic and bulky waste. The various waste streams are mixed thoroughly, because this homogenization ensures a high quality, a uniform as possible burnout and a good quality ash.
From the huge hall of the conveyor belts the waste enters the so-called residual waste bunker. Here it is stored a while until enough moisture has dissipated, so that it can burn well. By means of permanent temperature and humidity indicators it is controlled, in what condition the waste is. With large gripping cranes the waste is rearranged and finally placed in the kiln. The garbage gripper fill four huge funnels. The waste comes from here in four independently powered boilers that operate around the clock. The waste moves on roller grates through the boiler. And there it burns. At an unimaginable heat of 1,000 to 1,500 degrees Celsius. The respective “new” waste ignites from the already burning garbage. So no additional external energy is required for the combustion process. The combustion takes place after the DC principle: The burning of waste and the waste gases move in the same direction through the “hot flame” at the end of the grate. This procedure ensures that the destruction of pollutants such as dioxins and furans are already done in the combustion chamber.
From waste is made power for 250,000 people
And here is the highlight. The heat produced during combustion is used. On the one hand, to heat the nearby Ford plant. But this is just a nice side effect. The majority of the heat is converted into electricity by generators. And even that much that the power consumption of 250,000 people can be met. The waste incineration plant Cologne is thus basically a power plant and supplies a quarter of the city of Cologne with electricity. That sounds awesome. And since you could get the idea that it is not so bad when so much garbage is produced – as it is used so well …
After combustion bottom ash, hot exhaust gas and residues remain. These substances are largely used again useful: The ash is cooled with water and stored in an ash bunker before it is processed in a bottom ash treatment plant and then utilized in road, landfill and landscaping.
The hot exhaust gas is used for power generation. It heats preheated water to steam, which meets at a temperature of 400 degrees Celsius and a pressure of 40 bar to a turbine. This drives the downstream generator with which is produced electric power. For own use only a small part of the energy is needed. The greater part is given in external power supply networks. The amount of energy generated in the incinerator is enough to power more than 100,000 households.
In the combustion and the subsequent exhaust gas purification residual substances such as dust and salts remain as well as ashes from the boiler. These materials are collected and used as backfill material for the backfilling of salt mine tunnels. Gypsum is also a waste material, which is obtained as a reaction product in the exhaust gas purification and has building material quality.
Emission control: the exhaust gases are almost completely neutralized by the method used at the Cologne incinerator. There is no waste water, as well as the legal requirements are clearly undercut. As a neutral auditor, the county government gets the actual exhaust gas readings permanently by direct line.
Rethinking at waste management companies
After the guided tour, I had the opportunity to talk to the press officer of AVG. In this conversation it became clear how much the thinking has changed in the field of waste management in recent decades and years. While during the 1960s to the 1990s garbage was piled up completely unsorted in landfills and then forgotten, in the new millennium they have recognized the value of the waste. Climate change and CO2 emissions have long pushed as important issues in focus for the residual waste processing. The heat generated during combustion is converted into electricity. Resources are regained, as far as is technically possible. Especially metal, plastics and wood. The recovered plastic from residual waste is used for example as fuel for cement plants.
Waste incineration plant are nowadays equatable to power plants, even if the fuel value is not quite equivalent to the conventional fuels such as coal, oil and gas. As more and more municipalities have come to generate their own electricity by means of residual waste incineration, the major electricity providers get in significant difficulties.
At the end of the tour I was really impressed. That what is put in the residual waste in private households plus the commercial waste is, after all, still god to supply 100,000 households with electricity in Cologne.
And at the same time it’s scary, what incredible tonnes of waste we produce. Yellow and blue ton even come on top of that.
Consumer society provides garbage
Waste incineration plants generating electricity for us and making us less dependent on fossil fuels, are the logical consequence of our consumer society. But incinerators are not built primarily to generate electricity. But to become master of the mountains of waste that we produce continuously as a consumer society. Fortunately, with modern incinerators, a way has been found to make up the stinking problem a clean thing. But the cause, our consumption, is the real problem.
For the operators of the incineration plant, it is essential that enough waste is delivered. Garbage is their product. The more they can get, the better for the system’s capacity. For then it will work cost-effectively, which in turn has a positive impact on the urban garbage fees. Not all incinerators in Germany are so well utilized as in Cologne. Since waste is added from adjacent areas.
But the consumer society provides these masses of garbage. Goods are produced in large quantities, purchased, used or consumed and eventually discarded. The 2aste incineration plant gets food – in 2013 there were 707,000 tons in Cologne. And provides us even with power (282 million kWh in 2013 in Cologne). Actually a perfect cycle, so one might think. If not for this “but” would be. Because our conventional consumption goes at the expense of other countries, to the detriment of the environment, fair working conditions; Resources are wasted, the transport around the globe has impact on the climate, production facilities in the Far East poison the local environment and so on.
Well, I live in Cologne, a big city, where certainly only a small proportion of residents think about trash, disposal or even waste reduction and also practice this. That may be a negative point of view, but I think it is realistic. The average normal citizen does not necessarily ask the question what is actually happening to what he throws away in the course of a year. All the more it is interesting to follow the different paths. My next wish is to visit a recycling plant for plastics.
Waste incineration and waste seperation versus waste prevention
Waste separation was yesterday. The latest approach is waste prevention. In its most distinct version it is called Zero Waste. No waste. So far there are only a few pioneers, whose reports and videos I read and watch with interest. And at the same time I wonder how to implement this in a normal big-city life. It starts with the fact that – even if you use a togo box, which is compostable, then you do not know where to dispose of it along the way. So take it home and put it in the compost bin? Would everybody do that?
I think it’s great if it is possible, to be master of the situation (immense amounts of waste) through a well organized disposal system and beyond even to convert this residual waste to a large extent into energy, ie electricity and heating. There is at least a huge improvement as against the stinking landfill from earlier, in which everything was thrown into a pile and then covered with the cloak of silence. The next step must be, to reduce the amount of waste in total. And this will not be possible just by the civil society. Here politics and economy are asked to create the right framework and to set the practical implementation in motion.