What makes our sludge treatment process so good?

It is efficient, easy to maintain and compact. Additionally, it supports circular economy principles; it is sustainable and creates new revenue streams.

More precisely, the process is a combination of found to work, efficient technology targeted to solve many of the sludge treatment problems at once. The key component of the process is a widely used vacuum assisted thermal dryer, proven to be the best on the market*. Along with the dryer, we have merged simple, efficient technology to make a full process for nutrient recovery.  The end products – recycled fertilizers – are light and easy to use, and their selling price is cheaper than that of mineral fertilizers.

It is crucial to understand, that the end-product is not anymore waste – be it human waste or any other side stream: it is a processed organic nutrient product, in other words, recycled fertilizer. Extensive studies have been and are being conducted on this topic both in Finland and around the world. The message of these studies is clear: the use of recycled fertilizers – even sewage sludge-based – is safe. In Finnish sewage sludge for instance, the heavy metal content is clearly below the limit values set by law; the amounts of medical substances on the other hand are within the measurement tolerances. On top of that, recent study shows that Paskíer®Process destroys approximately 80 per cent of the microplastics in the sludge (> 100 μm) **.

The process saves nutrients while destroying all the pathogens. The NPK-value of the side streams differs, for instance sewage sludge in Finland has it around 12 per cent. The biggest portion is phosphorus, but also nitrogen is preserved throughout the process.

All together Paskíer® ensures better profitability for the company, together with easy installation and use. It is compact, automated, remotely controllable, and it can be connected to the rest of the facility’s automation. The dry granules are easily transported even long distances and they are suitable for fertilizing/seeding machines in use.

During the winter 2022-2023, we have been part in a carbon footprint calculator project of recycled fertilizer products. The project was piloted by the Finnish Biocycle and Biogas Association. From the calculator we will get solid, comparable information about the emissions of our end-product. According to our own calculations, the process itself has 20-to-80-fold smaller carbon footprint compared to current sludge treatment processes. Compared to mineral fertilizer production, the carbon footprint of our process is in the per mil range. Verified information about the CO2-eq of the end-products will be available later this spring.

Paskíer® has history for some six years now. In 2017 our CEO Jaakko Kuntonen started to do research to find an answer to the ascendant problems of nutrient recovery and sewage sludge processing. He combined his technical know-how and long experience in thermal drying with the burning need for modernization of sludge treatment.

After the development process, Paskíer® became the first method by which fertilizing products can be processed locally and with low emissions. The end-product corresponds mineral fertilizers, the only difference being that the fertilizers produced with Paskíer®Process are organic based. Any organic biomass can be used – be it from biogas plants, wastewater treatment plants or from process industry side streams.

How does the process work?

Sludge is fed to the dryer belt with an extruder. The smallest available belt opening is 150 microns. The vacuum fan creates a slight vacuum between the infrared radiators and the belt and at the same time draws air through the material. This removes water especially from the material surface and makes the drying process faster. Power is adjusted with the speed of the belt as well as with the infrared radiation: the radiation temperature is infinitely adjusted in the range 0 to 750 C . The drying process typically take 10 to 12 minutes.

After the biomass is dried in the vacuum-assisted infrared dryer, it is crushed, and it can be used as such as soil improver. Otherwise, additional soil and plant specific nutrients will be mixed to it, it is ground and packed and will be used as recycled fertilizer.

Contact us for further information,

Jaakko Kuntonen, CEO, jaakko.kuntonen@nanopar.fi phone: +358 522 5635

Mari Bahrami, marketing manager, mari.bahrami@nanopar.fi phone: +358 46 6433726

* The water evaporation efficiency with PSS infrared dryer is 2-4 liters/kWh while that of the other thermal driers is around 1 liter/kWh.

** Paskíer® removes most of the microplastics (> 100 μm) in the sludge. LUT University’s professor Mika Mänttäri and researcher, doctor Mirka Viitala studied the number of harmful substances transported into the environment through wastewater treatment plants. As part of the project, the microplastic content of sewage sludge was investigated before and after our Paskíer®Process. The results show that the calculated microplastics removal efficiency of the process was between 72 to 86 per cent, depending on the drying method. Thus, according to the research, the Paskíer®Process removes the majority of the microplastics (> 100 μm) contained in the sludge.