Andres Krumme, Professor at the Department of Materials and Environmental Technology, started by presenting a waste pyramid (Figure 1, in Estonian). Waste minimisation is at the base. Today’s economic models do not support this, but in the green century, waste must be taken into consideration when a company designs a product or a consumer buys it, not just when it becomes useless. Consumers will be able to choose products with less packaging and items with better quality that last longer or pass on used items rather than simply throwing them away. The more consumers make these decisions, the more motivated companies are to produce non-disposable goods because junk is no longer in demand.

The next step on the pyramid, or the second most important, is reuse. When a person or an organisation no longer needs something (clothes, furniture, equipment, household items, etc.), they pass it on to somebody else to use. It may need a little repair or reworking, but the product will continue serving in the same capacity.

Thirdly, recycling of materials. To do this, a product has to be dismantled and reprocessed and then used as a material for something new. Georg Logins, Head of the Facilities Management Division of the university, gave a number of examples of what can be done with the waste sorted at the university: 100 kg of glass can be used to make 200 bottles or jars; granulated white plastic from yoghurt cups can be used to make plugs and switches; waste paper can be used to make new paper and cardboard, egg cartons, notebooks, newspapers, toilet paper, etc.; biological waste can be turned into compost.

Fourthly, only when all the previous options have been exhausted, we resort to energy recovery, which means that discarded products are burned to produce energy. This will end both the product and the material cycle, but at least it will save resources in the amount of energy that we get from burning the waste. Among all else, mixed municipal waste from TalTech is used to generate electricity and heat in the Iru power plant. Krumme pointed out that many domains in Estonia face the problem of small local volumes. It is sometimes wiser to incinerate small amounts of waste because collecting them would require more resources than the energy gained from incineration.

The fifth and final option is to throw the item away without giving it a chance to be useful. This is the most problematic category – the contents of the mixed municipal waste bin. It could contain torn clothes and broken toys, used nappies and cat litter, cosmetics, office supplies, cigarette butts, used paper and broken tableware, broken plastic items, etc. The scientist confirmed that, in Estonia, mixed municipal waste is sorted to remove glass, metal, plastic, and paper packaging for recycling. The rest is incinerated for energy recovery and what remains from incineration is landfilled, as is large-scale mineral construction waste.

According to Professor Krumme, the main challenge in Estonia is to increase the amount of recovered materials from waste to more than 50%. In 2019, 31% was recycled. ‘The main concern is that mixed waste is too cheap to collect so people have no motivation to separate different types of waste and take it somewhere else,’ said Andres Krumme.

Georg Logins listed the ways TalTech as an organisation can reduce waste: our cafés have Cuploop and Ringo reusable food boxes and cups, and the campus has drinking water dispensers to reduce buying water that is bottled in plastic. Printing should only be used when strictly necessary, including minimising the production and consumption of printed materials. We need to buy only items that are high-quality and long-lasting, reuse where possible, and sort wisely when that is no longer possible.

Once he had explained the pyramid, Andres Krumme also urged everyone to do everything in their power as consumers to give products and materials the longest possible life and to sort waste. He also stressed this when listeners argued that sorted packaging is simply going to be incinerated or that there is no point in sorting the tiny bits of rubbish. Krumme explained that there are different technologies and production lines in waste management, with some using air flow for sorting and infrared for detecting plastic that is the size of a fingertip based on the density of the material, while others rely on manual labour for sorting only larger pieces. However, consumers do not know which line their sorted bottle cap will end up on and the lines are constantly being updated.

The professor admitted the absurdity of only real packaging being allowed in containers for plastic waste during the green revolution, but not, for example, broken plastic buckets or toys, even though this plastic is also recyclable. This is due to legislation that makes producers responsible for the collection of packaging, but not for other plastic products. Krumme recommends that consumers do their bit here – if possible, they should separate waste by material and occasionally take it to the waste plant themselves. ‘If we, as consumers, don’t do our part to direct waste to the right place, there is no point in expecting waste management companies to do it for us,’ the professor summed up waste sorting.