19.09.2019 BlogRobot against residual waste

The waste management company Carl F in Malmö receives and sorts approximately 40,000 tonnes of construction, demolition and industrial waste annually. Previously, 40% of this ended up as combustible residual waste, but after they installed Sweden’s first waste sorting robot, this percentage has been reduced to 10%.

Article by Johs Bjørndal, published in Kretsløpet magazine (Norway), 31 August 2017.

Carl F is a medium-sized waste management company in Skåne, which uses 4,500 containers and 45 of its own trucks to handle approximately 90,000 tonnes of waste per year. This includes 50,000 tonnes of source-sorted fractions, mainly metal, cardboard and plastic, while 40,000 tonnes consist of mixed waste, mainly from the construction industry. “We have treated this like all others, picked out the largest using an excavator, shredded and screened the waste and took out the metal using a magnet. But we saw that there was still a lot of recyclable material in this fraction. It also contained quite a lot of inert material, rocks and gravel, which meant that the fuel fraction had a fairly high ash percent, says Fredrik Nordh”, Marketing Manager of Carl F. He tells that the competition in the waste industry in Malmö is tough.

“Even in a good period like now, it is impossible to increase the prices. They have been the same since 2010. Therefore we must try to improve profitability by getting more out of the waste and limit the costs of further processing”, he says to explain the investment.


The unit, called Carl-Robot internally, was delivered by the Finnish company ZenRobotics, and takes automated waste management to a new level. The two arms can identify and pick out up to 4,000 objects per hour. It is truly revolutionary and equipped with Artificial Intelligence and is able to program itself. “It looks at the waste and creates its own algorithm. You should see the film Matrix to believe this”, said Rainer Rehn from ZenRobotics when he presented the concept at the Waste Conference in Kristiansand.

“Well, luckily it does nothing other than what we want it to do”, Nordh points out. And at Carl F, they have currently taught the robot to pick wood, metal and rocks out of the residual waste stream. “It is not just about removing fractions with value, but just as much about limiting the negative value”, says Nordh. He tells that they must pay around EUR 53 per tonne to deliver their combustible residual waste to Sysav, the inter-municipal waste management company in Skåne, which has two large waste incineration plants. “First and foremost, it is about extracting the heaviest material from this fraction, and after half a year of operation, we will be prepared to limit the amount of combustible residual waste by 12,000 tonnes annually”, Nordh tells. Which would imply a savings of EUR 636.000. Not insignificant for a company with a total turnover of around EUR 13.3 million.


Of the 12,000 tonnes that is picked out by the robots, approximately half of this is wood. Metals constitute approximately 2,000 tonnes, while the rest is inert material. Nordh tells that their cautious calculations do not assume any revenues from these fractions. The value of wood is approximately zero. Metals have a positive value, while the refined stone fraction must be crushed if it is to be used for something sensible. But the purity is impeccable. The wood is actually exported to Poland, where IKEA makes chipboard from it. They pay no more than a Swedish district heating plant, but it says something about the quality, Nordh says.

He also tells that in the beginning, the robots also picked out plastic, but that this resulted in a mixed plastic fraction that no one wanted and that they now allow plastic to go through the plant as combustible residual waste. “Instead, we will teach the robot to sort out PP and HDPE, i.e. bottles and cans for which there is a greater market”, he says.

However, a traditionally large recycling fraction such as cardboard and paper is not so easy to extract using the robot. “A picking robot has the restriction that it must have three-dimensional items to be able to identify and grab them. It will not grab paper or other things that are completely flat on the belt. Therefore, everything that goes to the robot is sorted in a ballistic screen first. Here, the flat objects will be separated. The next step for us is to build a separate sorting line for two-dimensional material, where there is a lot that is recyclable. But we have not decided yet whether it will be a robot solution here”, Nordh says.


The total investment for Carl F has been EUR 1.8 million, in which the pre-processing units are included. ZenRobotics has just delivered a complete plant, which also includes a feeding bunker equipped with walking floor.

“This [the bunker] is filled up with pre-treated waste before afternoon changeover takes place at 18:00. Then the robot has enough to work with until around midnight. After this, it stands waiting until people return to work again”, Nordh explains.

Here, Operations Manager Håkan Månsson adds that they reduce the speed a bit during the night, since there is not enough waste until the morning. This means that the robot will then pick out virtually all objects from the relevant faction. During the daytime, it is run somewhat faster when priority is given to the most profitable objects – picking metal – before the other factions. The two do not deny that they would like to have had more “food” for the robot. Månsson estimates capacity utilisation to between 70 and 80 percent. To the question of what can create trouble in the plant, he mentions rope and cords – probably recognizable for recycling operators, but not for robotised sorting.


So of course the question is how much waste is needed to justify such an investment. “I do not think we will see so many devices like this in Sweden. There must be at least 30,000 tonnes of suitable waste in one place”, says Nordh. What fractions are suitable for robot sorting? The plants which are in operation so far in Finland, the Netherlands, Japan, Singapore and China have implemented to sort construction waste or industrial waste. But at the Waste Conference, Rainer Rehn informed that testing on household waste in bags is in progress in both England and Germany. But it goes without saying that waste that must be picked and lifted by a metal clamp must be firmly on the hook.


Marketing manager Fredrik Nordh believes that the waste robot can provide competitive advantages, which have not been utilized up to now. “We now have the possibility of recycling material more than any others – and giving the customers completely accurate feedback on what exactly their waste contained and how much of that was recycled. We have not currently marketed this. Perhaps we are a bit apprehensive that the customers want to have their piece of the cake if they see that we are able to limit the costs, says Nordh. He has little faith in the customers wanting to pay extra for environmentally better waste management. “We may reach that point someday. We have enough customers who think it is fine to promote their environmental profile, but at the moment it is most about price. And a new solution can be as environmentally friendly as it will, but if it is not profitable at the same time, it will quickly disappear again”, he believes.


The plant in Malmö acts as a showcase for ZenRobotics, and the service level is in accordance with this. “Follow-up has been very close, and we have had almost no downtime at all at the plant,” says Nordh. He emphasises that neither the robot nor those who use it have been yet fully trained. “We have gotten it to work, but there are many more possibilities. We have two picking units that can sort four factions each, and we can easily increase to eight factions. For example, it may be relevant to remove stainless steel as a separate faction”, he says. And it is not difficult to teach the robot something new. You just send 100 objects of the desired faction through the system.

Carl Fredrik Jönsson is a fourth generation in the family business Carl F, which started transporting coal by horse 129 years ago. Today, the company has a turnover of EUR 13.3 million and has 65 employees, most of whom are drivers.

“We are competing with national corporations that have turnovers in the billions, so we must constantly think innovatively”, he says.