Stute goes green with in-house Krones recycling system

Stute has become the first company in the beverage industry to commission a PET recycling system in-house. With its bottle-to-bottle recycling capability, the company is processing its own PET waste and in future will also use non-returnable PET containers from its customers, using the decontaminated flakes as an admixture to the preform production process on injection-moulding machines.

Founded 130 years ago and boasting an annual turnover exceeding €400 million, Stute has a long history of incorporating green concepts into its facilities, from separating recyclable waste in the 1980s to establishing an aerobic sewage treatment plant in 1997. The company worked with Krones on several projects before installing the PET recycling system.

“By installing two Krones bottling lines with Contipure modules and without a rinser in 2009, we save 240 m³ of water a day in the beverage bottling operations,” said Christoph Frankrone, head of purchasing plant engineering at Stute.

“Our paramount concern is sustainability. However, this has to be cost-efficient as well. We shall be achieving both these goals with the recycling system.”

The system is currently dimensioned for producing 3500 tons of food-grade PET flakes each year. Given a bottle weight of 20 grams, this corresponds to 175 million PET containers - roughly equal to the complete output of two bottling lines.

Supermarkets and discounters with large distribution networks are the primary customers for Stute’s beverages sold in non-returnable bottles. Stute’s own recycling system enables it to take back the non-returnable PET containers. Bottles collected in supermarkets are generally pre-sorted in central warehouses. Stute’s recycling system means that the PET material could be accepted and processed in-house at Stute without any elaborate sorting required beforehand.

The in-house recycling system consists of a washing module and a decontamination module, both of them in rack construction. All decontamination processes have to be preceded by a washing process in order to obtain clean flakes as the material. It is here that label residues, glue, sand and other soluble soiling are washed off.

In order to achieve food-grade quality, the material must be decontaminated in accordance with international standards. In Krones’ Vacuum-Supercleaning process, the entire PET input material can theoretically be recovered. Krones is reportedly the only manufacturer offering both the washing module and the decontamination module - and thus a complete-system package - with the entire peripherals included if required.

Stute’s recycling system uses a new operator interface. In contrast to earlier versions, it provides all relevant data such as fill levels and temperatures in a single display. The display also shows easy-to-understand icons that show not only the actual value but also the prespecified setpoint value and the upper/lower tolerance window. If a measured value moves outside this range, the icon will change colour. This makes operator control much easier as operators do not require any in-depth technical knowledge.

The recycling system can also be expanded as required. In fact, the capacity can potentially be doubled in the space available at Stute. “The current output is a wonderful size for beginning with this kind of process,” said Frankrone. “How things develop from here will also depend on the market prices for plastic.

“PET recycling is a win-win situation for the retail sector and for us. The retailers provide high-quality PET material for recycling as high-quality food and beverage packaging, and avoid downgrading it (eg, for textile production in China), which means our customers can point to a closed-cycle system. This is firstly, sustainable and secondly, it’s cost-efficient, because we can also pay reasonable prices. On the other hand, Stute uses the material for producing new preforms, thus practising resource-economy as well as obtaining a financial benefit.”