Sustainability on the football pitch ‒ how old synthetic turf is becoming part of the new playing surface in Rotterdam

© FieldTurf

"Sustainability" and "eco-friendliness" are key considerations nowadays in the construction of synthetic turf sports facilities. And a particularly important issue, which has not been addressed hitherto, is the sustainable disposal of old synthetic turf systems. After between 12 and 15 years of use most synthetic turf surfaces in sports facilities need to be replaced – however, most of the old systems continue to be burned or alternatively simply stored as waste often to be exported overseas, where it is then often left to rot. From an ecological perspective this is a catastrophe. If one in addition considers that over the next decade more than 20,000 synthetic turf pitches are likely to need to be replaced in the EU, the scale of the problems becomes apparent: the volume of the plastics polyethylene and polypropylene for disposal alone amounts to over 500,000 tonnes. Which by itself begs the question: how can this volume of plastic be recycled and the burning or rotting of the material be averted?

Synthetic turf recycling ‒ so how can it be done?

Back in 2016, the synthetic turf manufacturer FieldTurf, working in tandem with the Morton Extrusionstechnik GmbH company in the town of Abtsteinach, began work on a process for the recycling of synthetic turf with the aim of being able to re-use parts of the old artificial turf system in a new system. This involves using the polyethylene fibres and polypropylene pitch backing fabric from old synthetic pitches to produce infill granulate which can then be used on new pitches. To do this, the old artificial turf fabric must first have the infill and sand removed from it and be shredded on site. These pieces of artificial turf are known as End of Life (EOL) synthetic turf. In the factory the next step is to remove metal content from the material, after which the old synthetic turf is again shredded and further impurities are removed. The virtually virgin EOL synthetic turf material shredded into small fibres which is eventually produced is then mixed with a newly-produced polyethylene compound to produce an infill granulate of thermoplastic polymers. This first infill granulate made from recycled synthetic turf is called "ProMax Hydroflex" and contains up to 30 per cent of polyethylene from recycled turf fibres from end-of-life pitches. Extrapolated to the granulate requirement of a synthetic turf pitch, the old turf of a full old synthetic turf pitch will be reused for the infill granulate of a new pitch through this percentage. One hundred synthetic turf pitches are expected to be successfully recycled at the plant in Abtsteinach in 2019 using this method.

This newly-produced recycled granulate was first used in the late summer of 2018 in the construction of the SV Rippenweier sports club's new synthetic pitch. The infill satisfies all the relevant technical and testing requirements for a wide range of sports.

 The Sportcampus Rotterdam

The "Varkenoord" training and education centre was until recently located in the immediate vicinity of Feyenoord's famous "De Kuip" ("The Tub") stadium and used by two smaller clubs as well as the Dutch premier league outfit. A few years ago, however, Rotterdam city council drew up a major master plan for the transformation of the entire area around the stadium. While a completely new football stadium was to be built in another location in the city, the "De Kuip" site was to be converted into an athletics centre, apartments and a club museum. The Varkenoord training centre was demolished to make way for the "Sportcampus Rotterdam" and the site was to be used for sports fields, new-build apartments and a recreation area. While some of the newly-planned sports facilities of the Sportcampus form part of Feyenoord Rotterdam's new FASC sports complex, sports areas which can be used by the public are also being built. Work got underway in 2018 on the demolition and renovation work on the new Sportcampus.
 In addition to a training stadium, the "Sportcampus Rotterdam" project also includes several new synthetic turf pitches, with the old synthetic turf surfaces having been recycled by FieldTurf using the methods described previously. All six full-size and three small pitches have been laid with synthetic turf, certified and are in use. With the installation of around 35,000 m² of synthetic turf pitches infilled with granulate from recycled old synthetic turf pitches the city of Rotterdam is blazing a trail in sustainability. When it is complete a total of 68.4 tonnes of synthetic turf will have been successfully recycled for this project.

Sustainability

The recycling method described offers further advantages in addition to avoiding the environmentally harmful disposal of old synthetic turf. For the traditional production of elastic infill granulate from crude oil is very energy-intensive and is also associated with a high level of CO2 and methane emissions. The manufacture of elastic infill material from old synthetic turf therefore results in a significant reduction in emissions. For a playing surface area of 8000 m² the use of recycled infill granulate saves around 640,000 kWh of energy and reduces CO2 emissions by over 70 tonnes compared with new material.

Moreover, material recycling can be extended even further with new synthetic turf pitches. This is because while conventional SBR and EPDM granules must be filtered out for the recycling process, TPE polymers and therefore also the "recycled" granulate can be reused in the next surface exchange together with the artificial turf. From 2020 FieldTurf is also planning to build further recycling facilities in France and the Netherlands to enable synthetic turf recycling to be undertaken on a large scale.

The Lehmacher Schneider testing laboratory in Osnabrück evaluates this recycling of old synthetic turf as follows:

"As the leading ISO 17025-accredited testing laboratory in Germany, Labor Lehmacher Schneider provides technical testing support in the area of material utilisation and recycling of existing synthetic turf pitches. The objective is a certification of the entire process in which as many components as possible of the old synthetic turf pitch can be recycled. 

For the Rotterdam project every effort was made to ensure that all parties involved in the project met the relevant local and national recycling standards and that only companies certified for the respective area were involved.

In the area of the manufacture of PE-EOL infill granules, production is regularly inspected to verify compliance with the requirements of the DIN standard and the RAL Gütezeichen quality assurance body. The produced material satisfies all the expectations of synthetic new granulate. 

The other system components of decommissioned synthetic turf pitches are also recycled today after they have been appropriately cleaned.

This means that the sand is reused in the construction industry, while in some European regions it is used in new synthetic turf pitches.

The EOL SBR granules are used in the manufacture of fall protection mats while there are also now synthetic turf pitches being installed in which the EOL SBR granules are built into the elastic in-situ layer. However, a large proportion is reused in the manufacture of new tyres.

In the long term the aim must be to completely recycle all the components of an old synthetic turf pitch so that waste generation is prevented and to minimise resource use for a new synthetic turf pitch."

Outlook

Overall, the environmentally-responsible disposal and recycling of synthetic turf surfaces is still in its infancy, especially in light of the strong demand and the ever-increasing number of new pitches. The production of infill granules from old synthetic turf fibres is a key first step as producers address the challenge of coming up with a new, more environmentally-sustainable solution. However, such initiatives need to be widespread and adopted quickly so that the large number of synthetic turf surfaces that will have to be disposed of in the future can be sustainably recycled. The city of Rotterdam has recognised the opportunity to lead by example, investing in a sustainable concept and at the same time acquiring top-quality new sports facilities.